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Evaluation of Selected Heavy Metal Concentrations in Soils of an Urban Stormwater Retention Basin


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EVALUATION OF SELECTED HEAVY METAL CONCENTRATIONS IN SOILS OF AN URBAN STORMWATER RETENTION BASIN By MARK S. LANDER A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2003

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Copyright 2003 by Mark S. Lander

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This project is dedicated to my parents D onald W. Lander, and Betty M. Lander. Your support has given me the ability to finish what I have started.

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iv ACKNOWLEDGMENTS I would like to express my deepest appreciation to my wife, Delia, daughter Caitlin, and son Kyle. This project was made possible with their love, support, and most of all patience. A special thank you goes to Larry Rex El lis. His assistance on this project goes beyond what any normal individual would have contributed. I thank him for being a great friend. I would also like to thank my gradua te committee: Dr. Ann Wilke, Dr. Randy Brown, Dr. Richard Schneider, and especially Dr. Mary Collins, committee chair. Their patience, understanding and insight have greatly influenced the outcome of this work. As I have now found out, it is not easy rais ing a family, working 40 hours a week, and conducting research. For technical assistance I would like to thank Larry Schwandes, and Tom Lounga, for their help with laboratory proce dures; Tom Seal, from the Department of Environmental Protection, for valuable docum ents; Andy Reich and Dr. Stephen Roberts for their time concerning toxicological inte rpretations; and my employer, the Alachua County Health Department, for allowing me the time to complete this degree.

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v TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................................................................................. iv LIST OF TABLES........................................................................................................... viii LIST OF FIGURES ........................................................................................................... ix INTRODUCTION ...............................................................................................................1 Urban Stormwater Runoff............................................................................................... 1 Floridas Stormwater Management Program.................................................................. 2 Stormwater Management Systems.................................................................................. 4 Deficiencies in Stormwater Regulation .......................................................................... 4 Research Site.................................................................................................................. .5 Overall Research Objectives........................................................................................... 7 LITERATURE REVIEW ....................................................................................................8 Characteristics of Urban Stormwater Runoff ................................................................. 8 Methods of Stormwater Management Control ............................................................... 9 Evolution of the Florida Urban Non-Po int Source (NPS) Management Program........ 12 Regulation of Stormwater in Alachua County.............................................................. 15 Local Governmental Regulations ......................................................................... 15 Water Management Districts ................................................................................ 16 Pre-Stormwater Retention Basin Soil Quality.............................................................. 20 Permitting of the Retention Basin at the NATL ........................................................... 24 Review of Past Stormwater Mana gement Studies In Florida....................................... 25 Criteria Used in Metal Contamination Analysis........................................................... 27 Chapter 62.777 F.A.C. Contaminant Cleanup Target Levels................................ 27 Soil Quality Assessment Guidelines (SQAGs)......................................................... 29 Baseline Concentrations for Trace Metals in Florida Soils ...................................... 30 Metals......................................................................................................................... ... 31 Cadmium (Cd) .......................................................................................................... 32 Chromium (Cr).......................................................................................................... 33 Copper (Cu) .............................................................................................................. 34 Lead (Pb)................................................................................................................... 35 Nickel (Ni) ................................................................................................................ 36 Zinc (Zn)................................................................................................................... 37

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vi Metal Attenuation in Stormwater retention Basin Sediments....................................... 38 OBJECTIVES....................................................................................................................4 1 Objective 1 Evaluation of Current So il Conditions for Future Studies ..................... 42 Objective 2 Comparison of Current Metal Concentrations in Basin Soils to Soil Target Cleanup Levels................................................................................................42 Objective 3 Comparison of Current Metal Concentrations in Basin Soils to Soil Quality Assess ment Guidelines .................................................................................... 42 MATERIALS AND METHODS.......................................................................................44 Site Description............................................................................................................. 44 Sampling Locations ...................................................................................................... 51 Field Procedures ........................................................................................................... 57 Laboratory Procedures.................................................................................................. 57 Metal Analysis .......................................................................................................... 58 Organic Carbon Content ........................................................................................... 58 Organic Matter Content ............................................................................................ 59 Particle-Size Distribution.......................................................................................... 59 pH Analysis............................................................................................................... 59 Statistical Methods.................................................................................................... 60 Estimating Metal Loading Rates................................................................................... 60 RESULTS ........................................................................................................................ ..62 Organic Matter Content ................................................................................................ 63 Organic Carbon Content ............................................................................................... 65 Soil pH ........................................................................................................................ .. 65 Particle-Size Distribution.............................................................................................. 68 Metals: Cadmium.......................................................................................................... 69 Cd vs. Baseline Concentration Levels ...................................................................... 69 Cd Concentrations Compared With Various Screening Levels................................ 69 Metals: Chromium (Cr)................................................................................................. 74 Cr vs. Baseline Concentration Levels....................................................................... 74 Cr Concentrations Compared With Various Screening Levels ................................ 74 Metals: Copper (Cu) ..................................................................................................... 79 Cu Vs. Baseline Concentration Levels ..................................................................... 79 Cu Concentrations Compared With Various Screening Levels................................ 79 Metals: Lead (Pb).......................................................................................................... 84 Pb Vs. Baseline Concentration Levels...................................................................... 84 Pb Concentrations Compared With Various Screening Levels................................ 84 Metals: Nickel (Ni) ....................................................................................................... 88 Ni Vs. Baseline Concentration Levels...................................................................... 88

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vii Ni Concentrations Compared With Various Screening Levels ................................ 88 Metals: Zinc (Zn).......................................................................................................... 92 Zn Vs. Baseline Concentration Levels...................................................................... 92 Zn Concentrations Compared With Various Screening Levels................................ 92 Linear Regression Analysis .......................................................................................... 96 DISCUSSION....................................................................................................................9 7 Simple Linear Regression........................................................................................... 104 Metal Loading Rates................................................................................................... 106 RECOMMENDATIONS.................................................................................................113 APPENDIXES A ACRONYM LIST OF AGENCIES AND PROGRAM AREAS .............................. 116 B ADDITIONAL FIGURES..........................................................................................118 C ANALYTICAL RESULTS ........................................................................................124 D REGRESSION ANALYSIS.......................................................................................136 REFERENCES ................................................................................................................141 BIOGRAPHICAL SKETCH ...........................................................................................145

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viii LIST OF TABLES Table Page 1. Soil clean-up target levels (SCTLs) for contaminated soils .............................................28 2 Soil quality assessment guidelines for heavy metals in study. ..........................................30 3. Baseline concentration for Florida Surface Soils..............................................................31 4. Sample site status for each cell evaluated.........................................................................56 5. Sediment analysis and methods used in study..................................................................58 6. Metal concentrations in stormwater runoff.......................................................................111 7. L-THIA generated loading rates compar ed to estimated total mass in SEEP. .................111 A-1. Common acronyms used in this text.............................................................................117 C-1. Particle-size analysis for cell 1 .....................................................................................125 C-2. Particle-size analysis for cell 2 .....................................................................................126 C-3. Particle-size analysis for cell 3 and control site............................................................126 C-4. Laboratory analysis for percent orga nic carbon (%OC), percent organic matter (%OM), and pH. ...........................................................................................................127 C-5. Metal Concentrations....................................................................................................1 29 C-6. Metal concentrations comp ared to regulatory guidelines.............................................130 C-7. Regression analysis on all sites, n = 38. .......................................................................132 C-8. Regression analysis on all sites 0 5 cm, n = 19..........................................................133 C-9. Regression analysis on all samples, 5 10 cm, n = 19.................................................134 C-10. Regression analysis on cell 1, 0 5 cm, n = 12..........................................................135

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ix LIST OF FIGURES Figure Page 1. Increased stormwater runoff expectations due to the loss of permeable soil surfaces .....2 2. Current agency infrastructure with respect to stormwater regulations.............................3 3. Photograph of the stormwater management system at the Natural Area Teaching Lab...6 4. The location of the Stormwater Ec ological Enhancement Project (SEEP) ......................17 5. Photograph of four-board fence borderi ng the eastern and northern region of the stormwater retention basin at the Natural Area Teaching Lab. .......................................20 6. Diagram of stormwater basin............................................................................................21 7. Location of Retention Basin at Natural Area Teaching Lab.............................................44 8. Layout of Natural Area Teaching Lab..............................................................................45 9. Photograph of stormwater runoff co llection area covered with debris.............................46 10. Natural areas and parking surfaces draining to the retention basin.. ..............................47 11. Original design of stormwater retenti on basin before enhancement project began........49 12. Diagram of the retention basin post enhancement that occurred in 1998.......................50 13. Breakdown of the sample cells insi de the stormwater retention basin...........................51 14. Location of sample sites in the stormwater retention basin............................................54 15. Sample site locations for the stormwater management system.. ....................................55 16. Percent organic matter in soils with in the stormwater retention basin...........................64 17. Soil pH at locations within the stormwater retention basin............................................67 18. Cadmium concentrations in the stormwater basin soils..................................................71

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x 19. Location of sites where cadmium concen trations were detect ed above threshold effects levels (TELs). .....................................................................................................72 20. Comparison of cadmium concentrations to screening criteri a throughout the entire basin.......................................................................................................................... ......73 21. Chromium concentrations in the stormwater retention basin soils.................................76 22. Location of sites where chromium was det ected above contaminant screening levels..77 23. Comparison of chromium concentrations to screening criteri a throughout the entire basin.......................................................................................................................... ......78 24. Copper concentrations in the st ormwater retention basin soils. .....................................81 25. Location of sites where copper was detect ed above contaminant screening levels........82 26. Comparison of copper concentrations to screening criteri a throughout the entire basin.......................................................................................................................... ......83 27. Lead concentrations in the st ormwater retention basin soils. .........................................85 28. Location of sites where l ead concentrations were det ected above threshold effects levels (TELs)................................................................................................................. 86 29. Comparison of lead concentrations to sc reening criteria throughou t the entire basin....87 30. Nickel concentrations in the stormwater retention basin soils........................................89 31. Location of sites where nickel concentrat ions were detected a bove threshold effects levels (TELs)................................................................................................................. 90 32. Comparison of nickel concentrations to screening criteria throughout the entire basin.......................................................................................................................... ......91 33. Zinc concentrations in the st ormwater retention basin soil. ...........................................93 34. Location of sites where zinc was detect ed above contaminant screening levels.............94 35. Comparison of zinc concentrations to sc reening criteria throughou t the entire basin....95 36. Diagram of the SEEP with areas of conc ern and short-circuiting path highlighted.......100 37. GIS photograph of the area adjacent to the stormwater retention basin.........................107 38. GIS land use classification designations for the areas surr ounding the retention basin.......................................................................................................................... ......108 39. GIS designated land use classes with in the retention basin watershed...........................109

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xi 40. GIS soils layer added to land use classifications. .........................................................110 B-1. 1988 proposed retention basi n with soil boring locations. ...........................................119 B-2. Soil boring locations 1 4. Borings conducted in 1988 by Bishop Beville for the University of Florida.....................................................................................................120 B-3. Soil boring locations 5 8. Borings conducted in 1988 by Bishop Beville for the University of Florida.....................................................................................................121 B-4. Soil boring locations 9 12. Borings conducted in 1988 by Bishop Beville for the University of Florida.....................................................................................................122 B-5. Soil boring location 13. Borings c onducted in 1988 by Bishop Beville for the University of Florida.....................................................................................................123 D-1. Regression curve for Cr, Ni, P b, and Zn; all points observed. D-2. Regression curve for Cr, Ni, P b, and Zn, with outliers removed. 138 D-3. Regression analysis for Pb and Ni in the top 5 cm of soil for every site throughout the entire basin.. D-4. Regression analysis for Pb and Ni in th e top 5 cm of soil for sites located in cell 1

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xii Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EVALUATION OF SELECTED HE AVY METAL CONCENTRATIONS IN SOILS OF AN URBAN ST ORMWATER RETENTION BASIN By Mark S. Lander December 2003 Chairman: Mary E. Collins Major Department: Soil and Water Science Treatment and disposal of urban stormw ater runoff have become major concerns when attempting to protect our surface and groundwater resources. Regulatory practices of the past were developed as watershed ma nagement tools, placing minimal emphasis on stormwater pollutant loads. Today, though, a dvanced studies in stormwater collection have shifted focus from a water quantity contro l issue to that of water quality. Currently the Florida Department of Environmenta l Protection, all five Water Management Districts, and local governments are worki ng together to develop safe stormwater management regulations. With basin desi gn being orchestrated for maximum water quality treatment, the soil becomes an integral part of system construction. However, the soils efficiency for pollutant removal from surface water may decrease overall soil quality, in turn promoting an unsuitable e nvironment within the basin for the existing ecosystem. Degradation of soil quality th rough pollutant accumulation raises issues on basin remediation and soil s handling and disposal.

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xiii This study was done to evaluate the cond ition of soils inside a constructed wetland detention basin at the Natural Ar ea Teaching Laboratory (NATL) site in Gainesville, Florida. Sampling was conducted inside the retention basin with the soils being analyzed for field parameters and heavy metal contaminant concentrations. Selected contaminant concentrations for C d, Cr, Cu, Ni, Pb,and Zn were measured and their distribution within soils of the wetland basin studied. The results indicated that metal conc entrations in the upper 10 cm of the stormwater basin soil varied for Cd ( 0.0 mg/kg 2.5 mg/kg), Cr (12.0 mg/kg 262 mg/kg), Cu (3.0 mg/kg 235 mg/kg), Ni ( 4.0 mg/kg 31.5 mg/kg), Pb (0.5 mg/kg 64.5 mg/kg), and Zn (6.5 mg/kg 720 mg/kg). Several of these sites exceeded soil quality reference guidelines used for contamination assessments. The majority of the contamination lay adjacent to stormwater in let pipes in the constructed wetland. The proximity and extent of metal concentrations did not suggest their migration outside of the constructed wetland.

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1 INTRODUCTION Urban Stormwater Runoff Urban stormwater runoff has long been co nsidered a major contributing factor of non-point source pollution to both surface and groundwater resources. The loss of permeable soil surfaces through urbanization can be expected as Floridas population is calculated to reach above 20,000,000 by the year 2020 (Florida Department of Environmental Protection, 2001). As land b ecomes covered with impervious barriers such as concrete and asphalt, infiltrative soil pathways become blocked, generating an increase in stormwater runo ff during rainfall events. Estimations made by the Florida Department of Environmental Protection (FDE P), indicate that a 10% to 20% increase in impervious surface area can double the amount of stormwater runo ff generated during a rainfall event (Livingston and McCarron, 1991) Stormwater runoff can reach as high as 55% of the total rainfall event if betw een 75% and 100% of land surfaces become covered due to urbanization (Figure 1). When exposed to impermeable surfaces, stormwater runoff collects materials deposited between past rainfall events. Runoff from impermeable surfaces has been shown to contain significant amounts of hazar dous contaminants, such as heavy metals, petroleum hydrocarbons, pesticides and many other types of organic chemicals (Cox et al. 1998). Previous research has shown variabil ity in contaminant concentrations at the same site over time (Livingston and Cox, 1995). It is this unpredictability that makes

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2 urban stormwater runoff an environmental th reat. Without knowing the extent or even the kinds of contaminants in urban stor mwater runoff it is difficult to assess the environmental implications that may be occurri ng. It is this same variability that makes establishing proper regulatory guidelines for the management of urban stormwater so important. Figure 1. Increased stormwater runoff expect ations due to the loss of permeable soil surfaces (Diagram taken from The Florida Department of Environmental Regulation reference manual, Stormwater Management A Guide for Floridians, Livingston & McCarron, 1991.) Floridas Stormwater Management Program The current state infrastructure for urba n stormwater management consists of a multi-agency coalition between the Florida Department of Environmental Protection (FDEP), Floridas five regional Water Management Districts (WMDs), and local governmental agencies (Figure 2). The FDEP serves as the umbrella agency for urban stormwater regulation by implementing th e states Non-Point Source Management Program (NPSMP) (Cox et al. 1998). Regional regulation of the NPSMP has been

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3 delegated to the WMDs allowing for more flexibility to address centralized issues through regional goals & policies. Local gove rnment has the responsibility for adopting comprehensive land use plans in accordance with the states land planning agency, the Florida Department of Community Affairs (DCA). By developing and implementing stormwater master plans addressing curren t and future growth expectations local governments have the ability to establish controls for monitoring the operation and maintenance of stormwater collection systems. In addition to their regulatory capacities, local governments have been given the author ity to establish stormwater utilities fees creating funding sources for local stormwat er programs, thus making cities less dependent upon state funding for program implementation. Figure 2. Current agency infrastructure with respect to stormwater regulations. The Florida Department of Environmental Protection (Non-Point Source Management Program) Floridas Five Regional Water Management Districts (Regional Goals Addressed Through Watershed Management) Local Governmental Agencies (Regulation Through Local Comprehensive Plans)

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4 Stormwater Management Systems With the regulatory controls in place, urban stormwater runoff is addressed under the NPSMP by the use of stormwater management systems. Common types of these include retention or detention type basins. These systems are designed to collect, hold and treat stormwater before reaching its fina l destination, whether it is ground or surface water recharge. Older stormwater basins were designed for water storage with little attention being placed on treatment (Athayde et al ., 1983). New basin construction and some older retention basins are being re designed using Best Management Practices (BMPs) within the stormwater management system, such as grassed swales and constructed wetlands to treat stormwater pollutants. Vegetation and soils in combination with varied water retention periods may pl ay a major role in cleansing pollutants from stormwater entering these systems. Deficiencies in Stormwater Regulation Over the past 30 years the focus of stormwater management has shifted from a water quantity based approach to that of overall water quality. Current regulations address criteria that must be met for the st orage capacity of stormwater basins and for water quality in systems that discharge to su rface waters. Pollutant toxicity build up in stormwater basin soils is not addressed, unless the soils ar e being considered for land application or landfill disposal. Even these concerns have led to only unofficial disposal requirements. It’s the soil’s ability to partition certain pollutants that make it both desirable and hazardous to the ecosystem of the overall stor mwater management basin. Without proper controls, excessive pollu tant loading of soils in stormwat er basins may lead to elevated

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5 levels of contamination, that under certa in environmental conditions could become available for exposure to humans, aquatic or ganisms and other various wildlife species. Livingston and Cox (1995) studi ed sediment toxicity buil dup in stormwater basins to establish guidelines for sediment dis posal. This study was expanded upon in 1998 looking at comparisons of pollutant buildup ove r time in basin sediments to the specific land use category. The recommendations for remedial action as a measure of loading time were difficult to assess due to sampling inconsistencies between locations. It was determined that more data would be required before sediment disposal guidelines can be established (Cox et al. 1998). The argument opposing soil toxicity c oncerns is supported by the ideology of presumptive operation and maintenance. Th at is, stormwater retention basins are designed to collect and treat runoff before it is allowed to re-enter a clean water source. With loading of stormwater basin soils by contaminants assumed, and as long as the basin is being maintained and operating as originally permitted, the contamination becomes a function of the permit (Still, 2000) A second reinforcing factor to this argument is that, in general, stormwater basins are not created for, or intended to be part of a human/wildlife exposure scenario. As th e use of integrated wetlands in stormwater treatment basins become more prevalent, however, this interaction becomes inevitable. Research Site The stormwater retention basin at the Natural Area Teaching Laboratory (NATL), located on the campus of the University of Fl orida, is representati ve of how the second assumption in regards to stormwater contaminant issues may be flawed. The basin, which first was designed to collect and trea t stormwater for disposal through slow soil

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6 infiltration, initially had minimal emphasi s on vegetative or ecological communities. Through redesign, however, this basin has now become an integrated wetland, creating an attractive environment for wildlife such as alligators, wading birds, and other avian species (Figure 3). In addition, the University of Florida has begun to use this facility as an interactive research site. Pr evious literature suggests, th at while constructed wetlands have become effective BMPs for secondary wastewater treatment, their ability to treat urban stormwater runoff has not b een extensively studied (Carleton et al. 2000). This site offers researchers the ability to asse ss basin performance and the effectiveness of various wetland species and basin design w ith respect to stormwater treatment. By making this site available for study and cr eating a desirable environmental habitat through vegetative cover and water resources exposures to possibly harmful levels of toxic contaminants becomes an issue. Figure 3. Photograph of the stormwater management system at the Natural Area Teaching Lab, looking south.

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7 Overall Research Objectives There are currently no regulations requiri ng monitoring of stormwater retention basin soils for contaminant build-up. A practical solution, may be to increase public awareness on stormwater constituents, and thei r ability to accumulate in these basins. In addition, the owners of these systems may not realize the potential exposure hazards that exist. The objectives of this study we re developed around the lack of regulatory requirements for stormwater ba sin soils, and pub lic awareness. First, by evaluating soils throughout the ba sin for metal concentrations, organic matter content, organic carbon content, pH, and particle size, i ssues concerning health implications not currently considered in basin permitting considerations could be addressed. A second goal of this study was to gene rate background data on the stormwater retention basin for the University of Florida to use with future studies at the research site. These data could provide valuable inform ation for evaluating wetland efficiency in treating stormwater, as well as in providing in sight to the current c ondition of the basin. Soils play an integral role in determ ining how various land developments may proceed. On some occasions short-term treatme nt capabilities of soils are considered for permitting possibly overlooking long-term effects. Therefore, a third outcome of this study is to increase awareness on soil contam ination in stormwater management systems. Understanding of such systems can lead to protective measures which can create a safe working environment for all. Throughout this document, a number of acronyms are used for various agencies and technical documents. A ta ble defining all acronyms used in this thesis can be found in Appendix A.

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8 LITERATURE REVIEW Characteristics of Urban Stormwater Runoff Improper management of stormwater r unoff from urbanized areas can have a downstream affect on both ground and surface water resources. Focus of stormwater regulation in the past had been limited to issues of sediment control or flood relief. Today this regulatory trend is shifting towards a water qual ity approach, recognizing the many different pollutants carried within stormwater (Athayde et al. 1983). A study released by the Nationwide Ur ban Runoff Program (NURP) in 1983, detailed a variety of stormwater pollutants be ing identified in urban runoff. Two of the primary contaminants detected were heavy meta ls and organic priority pollutants, such as pesticides and vol atile organics. Results from the NURP study indicated that heavy metals were more frequently detected in stormwater runoff than any other priority pollutant. While all of the 13 metals on EPAs priority pollutant list were detect ed in runoff analyzed for this study, copper, lead and zinc had the highest detection percen tage, found to be presen t in at least 91% of the samples. In some instances concentra tions were detected above freshwater acute criteria and federal drinking water standards (Athayde et al 1983). Organic pollutants were not detected at the same frequencies as the metals. Volatiles, pesticides, and phenols made up th e majority of organic priority pollutants detected. Detection values ra nged from 22% of the samples to less than 10% for others.

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9 A possible limiting factor for detection may have been that the monitoring scheme used allotted only a limited number of prior ity pollutant samples taken (Athayde et al. 1983). Further contaminants noted during the st udy were coliform bacteria, nutrients, oxygen demanding substances, and total suspended solids (TSS). Additional studies have indicated that copper, zinc, cadmium, lead, and possibly nickel, are major components of pollution from urban stormwater runoff (Mikkelsen et al ., 1997). There is difficulty in predicting pollutant loads within urban stormwater runoff. Variability of pollutant concentrations have b een seen at a particular site from one storm event to the next (Athayde et al ., 1983). Another factor dete rmining variability may be seasonal influences. Higher concentrations of pesticides may be detected in stormwater runoff during warmer months, when land app lication increases. In contrast, volatile components may decrease during summer as the temperature controls volatility (Fischer et al. 2003). With stormwater runoff, the goal is to direct flows from watershed areas to a defined boundary for isolation and treatment. Retention basins may act as a pollutant trap for various contaminants through soil adsorption and volatilization, other more soluble contaminants may pass through th ese systems to groundwater (Mikkelsen et al ., 1997). Methods of Stormwater Management Control As our knowledge of identified pollutants carried within urban stormwater runoff increases, and we determine the threats that they may pose to natural resources, questions on how to control this problem must be a ddressed. The current response is to mix methodologies of the past with the concept of best management practices (BMPs). In

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10 some instances there may not be one solution to a stormwater runoff problem, but instead a variety, or train of applications may exist within a single stormwater system. Best Management Practices can be separa ted into two distinct categories; nonstructural, and structural. Non-structural BMPs rely h eavily upon public education and regulatory controls for effectiveness. Ma king consumers aware of potential impacts from everyday household chemical usage, may lead to less overuse or abuse. Additionally, regulatory constraints along with proper pl anning can control materials and in turn develop acceptable guidelines for application (Lawrence et al. 1996). Structural controls are methods used in stormwater systems to reduce the impacts of erosion, flooding, and the magnitude of po llutant loading to waters. Methods of structural controls are deve loped around the collection and c ontainment of stormwater to allow for settling and filtration, as well as chemical and biological treatment. The particular methods used in structural c ontrols should be desi gned around site specific characteristics. In Florida, particularly in the southern part, high wet season water tables create a need to protect groundwater supplies from contamination by polluted stormwater runoff. In these areas, the most common type of st ormwater management systems are retention or detention type basins (Rushton & Dye, 1993) Retention basins ar e designed to collect and retain stormwater runoff on site. The pr ocesses of treatment are infiltration through the soil and loss through evapor ation. Detention basins are similar to retention, in the aspect of stormwater collection, but in fact, their primary objective is to act as temporary storage of stormwater before releasi ng it to a downstream water body. Extended stormwater residence times between 24 and 48 have been shown to be effective in

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11 allowing for sedimentation of suspended pa rticles and microbiological treatment of stormwater contaminants. Both retention and detention basins have been shown to remove metals from stormwater with an efficiency between 60 and 80% (Lawrence et al., 1996). In some instances more than one BMP is used in a single stormwater treatment system. Examples of other methods incl ude percolation trenches, grassed swales, pervious pavement, vegetative waterways, and street sweeping. Many of these methods rely heavily upon either quick in filtration or vegetative speci es to reduce pollutant loads. One emerging BMP in stormwater treatment is the usage of wetlands in combination with retention or detention systems. Studies have indicated the ability of we tlands to act as a filter or sink for stormwater pollution either through sedime ntation or soil adsorption, while providing flood protection. The dominant process in po llutant removal from stormwater may be sedimentation, however, indications are that vegetation and sediment/organic matter relationships can be important in providi ng sites for metal precipitation (Walker and Hurl, 2002). Goulet and Pi ck (2001), studied the eff ects of cattails on metal concentrations and partitioning in surficial sediments of a wetland basin. Their study indicated that the presence of cattails did not appear to have an affect on metal concentration or partitioning of metals within the stormwater sediments. It did show that areas where cattails were pr esent tended to have higher organic content within the sediments than zones where emergent vegetation did not exist. Cheng et al. (2002) evaluated the metal uptake in the tropical-subtropical swamp species C. alternifolius and V. exaltata. Contaminated stormwater passing through a

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12 wetland planted with the species experienced heavy metal removal rates at approximately 100% from inflow effluent metal concentr ation to water exi ting the system. A comparison was made between metal accumulation in the soils and plants. C. alternifolius proved to be an efficient vegetative species for removing heavy metals. In addition to its ability to uptake pollu tants, many plants store these contaminants in underground organs, but C. alternifolius stores them in lateral ro ots forming just below the soil-water interface. This makes it necessary to remove only a few cm of contaminated soil when attempting site remediation (Cheng et al. 2002). Further studies usi ng both floating and emergent vegetation have shown similar results of heavy metal removal, reducing their concentrations to an average of 85% (Kao et al. 2001). With removal of contaminants being a primary focus on environmental protect ion, we might expect to see more systems relying on vegetative we tlands as a BMP style. Evolution of the Florida Urban NonPoint Source (NPS) Management Program In Florida, increasing concerns of surface and ground water degradation through contact with contaminated urban stormwater has led to changes in the methodology for stormwater disposal. In the past, urban stormwater runoff was addressed as a water quantity problem, controlled by collection a nd storage methods. However, by the mid1970s evidence was present indicating that over half the pollutant load entering Florida waters came from non-point source runoff (Rushton et al. 1993). To combat the concerns of pollutant loading to water res ources from urban stormwater runoff, Florida developed a comprehensive watershed mana gement program involving federal, state, regional, and local governments.

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13 Regulation of urban stormwater runo ff is vital in preserving Florida’s environmental resources. Up until 1960, wate r quality effects from stormwater pollution received little attention (Athayde et al. 1983). From 1960 until the early 1970s, studies began to address pollutant identification in stormwater, but little significance was given to developing specific discharge requiremen ts. In 1972, the Federal Clean Water Act was amended to prohibit the discharge of any pollu tant to navigable waters unless authorized by a National Pollutant Discharge Elimina tion System (NPDES) permit. Non-point source pollution was now being recognized as a major contributing factor to water quality problems. With the promulgation of EPA’s first stormwater regulations in 1973, urban runoff was exempted unless coming from an i ndustrial or commercial process containing known contamination. In addition, regulation of the smaller urban stormwater discharges was left up to state and local governments. The lack of direction in stormwater mana gement in the mid-1970s led to initiation of the Nationwide Urban Runoff Program (NURP). The goals of the NURP were to provide all levels of government with management options for handling polluted stormwater discharges. It was these nationa l investigations along with various Florida studies, which laid the foundation for Fl orida’s Urban Stormwater NPS program. In 1979, Florida’s first stormwater rule, Chapter 17-4.248, F.A.C., was implemented by the Department of Envir onmental Regulation (DER). Under this Chapter, the issuance of stormwat er permits was dependent upon the “significance” of discharge. Variability in the determination of “significant” by regulators made this an impractical approach. The state’s Envi ronmental Regulation Commission adopted a revised stormwater rule, Chapter 1725, F.A.C., in 1982. Past concerns of

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14 inconsistencies in permitting were addressed by requirements for permits on all new stormwater discharges and for modifications to existing discharges where pollutant loads increased (Florida Department of Environm ental Protection, 1993). With the adoption of the revised chapter, Florida became the firs t state in the country to require the use of BMPs as a practical method of stormwater treatment. In effect, performance based standards established in Chapter 62-40, F.A.C ., were set to control quantity and quality of stormwater discharges, with emphasis plac ed on water quality exiting the system. From 1984 to 1986 the focus of regulation shifted from state to regional. The Southwest Florida Water Management Dist rict (SWFWMD), St. Johns River Water Management District (SJRWMD), and Su wannee River Water Management District (SRWMD) adopted regulations in line with DER stormwater rules, allowing DER to delegate permitting authority to each WMD. Thus, stormwater rules were put in place to address watershed management needs on a regi onal basis instead of the state as a whole. Building upon the DER – WMD stormwater permitting relationship, the Florida Legislation modified Chapters 373 and 403, F.S. The overall effect was the combining of the WMDs Management and Storage of Surface Waters permit with the newly formed Department of Environmental Protection’s (D EP) Wetland Dredge and Fill permit. The combination of these two permits created what is now known as an Environmental Resource Permit (ERP). ERPs allow either ag ency to evaluate both stormwater quantity and quality impacts, depending upon the proposed development. State and regional regulat ion are not the only cont rols when determining stormwater project acceptability. The DC A is the agency responsible for the implementation of the state’s growth manage ment program. Several statutes establish

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15 goals and directives for growth management throughout Florida. Specifically, Chapter 163, F.S., contains language including the Local Government Comprehensive Planning Act and Land Development Act of 1985. Both address local government’s responsibilities in land management, defini ng the requirements for the preparation of local comprehensive plans and direction of la nd development. The direction of the local government must be in conformance with th e overall policies set forth by the state and regional regulators (Florida Departme nt of Environmental Protection, 2001). Regulation of Stormwater in Alachua County Local Governmental Regulations Stormwater management systems in Alachua County are subject to review at the local, regional, and state levels. The City of Gainesville and Alachua County each has its own ordinance regulating stormwater manageme nt systems. City Ordinance, Chapter 27, Article V, Section 27-238 ( 1998), established the forma tion of a water management committee. The responsibility of the comm ittee is to assess wate r quantity and quality issues, and to assist in the development and implementation of sound water management practices. Included issues are stormwater di scharge and erosion and sediment controls in stormwater management systems. Jurisdic tion of the committee extends within the City boundaries as well as adjacent lands, which may affect the City watershed areas. In addition, Chapter 30, Section 30-270 (1992), addr esses applicable standards for erosion and sedimentation control, design, and mainte nance of stormwater management systems. However, the design phase defaults to ex isting state and WMD codes, with emphasis based on storage capacity and discharge quality of stormwater.

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16 Alachua County has taken a similar appro ach to addressing stormwater issues in its unincorporated areas. Title 4, Ch apter 44 (1996), established a stormwater management utility (SMU) to oversee perm itting outside all unincorporated boundaries. The SMU, made up of the board of County Commissioners, is respons ible for regulating all stormwater discharges through a review of conceptual plans, proposed system usage, required maintenance, and continued operation of stormwater management facilities. As part of the Local Government Comprehensive Planning and Land Development Regulation Act established under Chapter 163, F.S., Alachua County adopted Title 34, Chapter 343 in 1992. Under 343, design, construction and operation components of stormwater management systems are define d. As with the city ordinances, basic regulation is adopted from state and WMD regulations. Emphasis on flood control and storage capabilities, along with ground and surface water protecti on is in large the driving force behind county regulations. Additional local governmental regulations regarding st ormwater discharges and water quality have recently been implemen ted. The Alachua County Environmental Protection Department (ACEPD) drafted a 2002 ordinance pertaining to water quality standards and management practices for both the incorporated and unincorporated areas of Alachua County. The ordinance, which became effective January 1, 2003, establishes new standards defining allowable discharges to stormwater systems. Erosion and sediment controls will be increased thr oughout the county, and powers of enforcement on non-compliance or illicit activitie s will be given to the ACEPD. Water Management Districts Regional permitting for Alachua County is handled through delegation from the FDEP to the WMDs. The majority of wate rshed issues in Alachua County are directed

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17 either through the Suwannee River Water Management District (SRWMD) or the St. John River Water Management District (S JRWMD). The stormwater basin for this research is located near th e center of Alachua County in the northwestern portion of the SJRWMD (Figure 4). Figure 4. The location of the Stormwater Ecol ogical Enhancement Project (SEEP) at the Natural Area Teaching Lab (NATL) in Alachua County. Permitting requirements for stormwater runoff in the SJRWMD are established in several regional codes, using ERPs as the mechanisms for regulation. Chapter 40C-4,

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18 Surface Water Management Systems, establishes guidelines for the management and storage of surface waters located within the District. The structure of these guidelines is in accordance with FDEP standards set fort h in Chapter 62-40, F.A.C., and Chapter 373, F.S. Under Chapter 40C-4, the SJRWMD has established conditions for stormwater permitting in addition to defining a management structure for regulatory purposes. Taking stormwater management a step fu rther, in Chapter 40C-42, Regulation of Stormwater Management Systems, the District established standards to control discharges initiated from stormwater runoff. Include d within the chapter are requirements for system design and construction, performan ce criteria, special exemptions, operation, monitoring, and maintenance. As with the local ordinances establis hed for stormwater runoff, WMD and FDEP regulations address mainly water storage and quality of discharge issues. Requirements for monitoring pollutant build-up in stormw ater sediments are not addressed to any extent. To better understand the regulat ory absence on soil contaminant build-up, phone interviews were conducted with both SJRWMD & SWRMD staff. Information from the interviews indicated that permitted stormwater management systems are inspected on a routine basis. The emphasis of the inspections is on sediment and debris accumulations, and structural integrity of the basin. Soil contaminant concentrations are not evaluated unless the permitting agency has reason to su spect the basin is not functioning as it was originally permitted. The neglect of contaminant evaluation requirements is justified by the term presumptive operation and maintenance. In simple terms, stormwater retention basins are designed and constructed to collect and treat runoff for pollutant removal before allowing infiltration to ground and surface water resources. A major

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19 component of the treatment process is the soil’s ability to filter out contaminants at its infiltrative surface. If a stormwater system is functioning properly, then the removal of pollutants from the water column and subseque nt build-up of contaminants in the soil is merely a function of the system. A second pa rt of the equation of pollutant so il build-up in stormwater management systems is the fact that these basins ar e not designed with the intent of frequent human and wildlife interac tions. The intent of stormwater management is to localize contaminants by directing stor mwater to a centralized location. Access to these areas is then commonly limited or disc ouraged through the use of fencing or other restrictive measures. This last thought process is not the case with the NATL stormwater retention system. There are no restricted barriers to limit public access, such as chain link or stockade fences. The only defining border ar ound the basin is a 4-board fence to the east and north with several access points (Figure 5). In addition to not limiting access, a boardwalk has been installed inside the stor mwater basin, which allows entry to almost the entire area (Figure 6). Additionally, basin landscaping has created an environment that attracts and sustains a variety of wild life. The research opportunities created by the stormwater basin make this area a valuable s ite for the University. A lack of current stormwater soils data at this location creates a gr eat opportunity of study. It is should be recognized though, that the absence of requ irements for contaminant regulation in stormwater basins may create a poten tially hazardous working environment.

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20 Figure 5. Photograph of four-board fence bo rdering the eastern and northern region of the stormwater retention basin at the Natural Area Teaching Lab. Pre-Stormwater Retention Basin Soil Quality Lacking actual laboratory data on the so ils in the vicinity of the stormwater retention basin, soil quality befo re the construction of the retention basin could only be estimated. The control samples located outside the retention basin ga ve insight to surface horizon conditions. Additionally, logs of soil borings completed during the initial construction phase on the stormwater basin we re located and compared to existing soil maps of the area, giving a broader view of the subsurface horizons that existed pre-basin construction (Beville, 1988).

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Figure 6. Diagram of stormwater retention basin. A) Boardwalk location in the retention basin as noted by red line. B) Photograph of students using the boardwalk to enter the retention basin. A) Boardwalk B)21

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22 Soil maps in the Soil Survey of Alachua County Florida (Thomas et al. 1985), indicate that before this ar ea was dedicated entirely to stormwater management the dominant soil series in the area were Arredondo, and Kendrick. The classifications of these soils are similar as are their parent mate rials. Both series are in the Ultisol order, but the Kendrick series is classified as a loamy, siliceous, semiactive, hyperthermic, Arenic Paleudult, indicating a shallower ar gillic horizon present than in the Arredondo, which is classified as a loamy, siliceous, semiactive, hyperthermic, Grossarenic Paleudult. Soil borings, conducted by Dr. Bishop Bevi lle in 1988, indicated the major soil materials to be fine sands overlying fi ne sandy loam and sandy clay loam horizons. These borings were taken at selected areas w ithin the then proposed retention basin being constructed around an existing natural depre ssion. Additionally, it wa s noted in several areas that the “clayey materials” were clos e to the surface, indicating possible removal of the topsoil. The sandier soils were determined to be located in th e northern end of the site, in what is now the forebay. Fine-sand textured soil material was measured to depths of between 76.2cm to as deep as 167.6cm, with the exception of one site at the northernmost point of the ba sin (Beville, 1988). The re maining fine sand horizons became thinner as the existing pond was encro ached upon. The presence of water tables at several borings was probably due to the pe rching ability of the clay in the subsurface horizons and the fact that this area, the existing pond, was the natural watershed for the surrounding lands. These documented water ta bles are not typica lly observed in the Kendrick or Arredondo soils. However, water tables can be present in the Millhopper soils, which is geographically associated a nd classified the same as Arredondo. Another

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23 indicator hinting to the clays ability to hold or retain water, was the identification of redoximorphic features within and above the ar gillic horizons. Data from the soil boring logs, matrix color or indicated “mottles, sugge sted the presence of e ither a current or wet season water table within 2 m at every locati on (Beville, 1988). A complete list of the soil borings and a map detailing their locations within the pr oposed basin are in Appendix B, Figures B-1 through B-5. Working on the assumption that the soil se ries at the location of the stormwater basin were either Kendrick, Arredondo, or Millhopper, estimates on soil quality parameters can be obtained from Tables 15 and 18 in the Soil Survey of Alachua County, Florida (Thomas et al. ., 1985). The soil survey gives estimates in the ranges in organic matter content for the surface horizons of the three soil series in question. Both the Kendrick and Arredondo soils have an estimated organic matter conten t of less than 2% in their surface horizons. The Millhopper soil has a range of 0.5-2% or ganic matter content in its surface horizon. The soil survey additionally lists laboratory data from the Environmental Pedology Lab in the Soil & Water Science Depart ment at the University of Florida. pH and organic carbon content are shown for diffe rent soil series. The pH for surface horizons in these three soil series ranges fr om 5.6 in the Kendrick series to 6.0 in the Arredondo soil. The Millhopper soil has a pH in the surface horizon listed at 5.9. The subsurface argillic horizons, which are now e xposed due to the creation of the stormwater basin, would have a pH range of 5.2–6.0 in th eir original pedogenic stages. Organic carbon content in the surface hor izons of these soils ranges from 0.15% in the Arredondo soil to 0.57% in both the Ke ndrick and Millhopper soils. With increasing soil depth,

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24 organic carbon content decreases In the Millhopper soil, the organic carbon content decreases to approximately 0.03% in the Bt g horizon, while the organic matter content of the Bt horizon in the Kendrick soil is between 0.13–0.15%. The Arredondo soil shows a range of 0.06–0.09% organic carbon co ntent in the Bt horizons. It should be noted that these numbers ar e not absolute for the soils that were present in the area of the stormwater basi n before its constructi on. However, by using these as a reference point and compari ng them to current conditions, insight on anthropogenic influence from urbanization can be observed. Permitting of the Retention Basin at the NATL The retention basin serving the NATL was first permitted by the SJRWMD in 1988 under the University of Florida Master Drainage Plan as Basin #8. The original design criterion was based on stormwater collection from a 14.45 ha watershed. Stormwater runoff from a 100-year storm ev ent based on a 24-hour period was calculated to be 18,855 m3 for this watershed. Additional r unoff from the Entomology/Nematology Building and from the Florida Department of Transportation (FDOT) Park ‘N’ Ride lot, serving the University of Florida, was dire cted to the basin in 1990, bringing the entire watershed area to approximately 16.19 ha, increasing the total runoff flows to31,075 m3. A note to the master plan indicated the proposed maintenance of the system to include monthly inspections, and inspect ions after each major storm event for debris and erosion. Additionally, silt removal from the basin bottom in the areas of the outfall locations was to be completed twice a year. There was, however, no reference to the evaluation of soil sediments for contaminant build-up. In 1996, SJRWMD permit #40-001-0029AG, was issued for the re-contouring of the SEEP due to the system being redesigned with the

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25 constructed wetland. Under this permit, c onditions of the origin al application were maintained with no requirements for sedime nt analysis. Basin function evaluation on storage capabilities and structure continued to drive the permitting side of UF Basin #8. Review of Past Stormwater Ma nagement Studies In Florida Over the past 10 years there have been a number of stormwater studies in Florida that have led to either direct or indirect regulations being applied to permitting practices. These studies have included evaluations on BMP styles, treatment capabilities of differing basin classificati ons, and land use impacts on stormwater quality. With emphasis in these studies being placed on wate r quantity and quality, soil evaluation for contaminants many times is looked at as a side note. In 1995, however, DEP completed an intensive literature review and monito ring project of stormwater systems across Florida. When DEP completed its literature review, it was noted that existing data on stormwater sediment characterization wa s sparse and not eas ily correlated due to variation in sampling methodologies (Livingston et al. 1995). From the data obtained in previous studies, and those collected duri ng the course of the 1995 investigation, DEP evaluated stormwater sediments from over 87 sites, from differing land use classifications, within Florida. Sediment screening took place for a total of 168 different pollutants, including pestic ides, organic contaminants and trace metals (Cox and Livingston., 1995). Metals in the DEP study were evaluated for their concentrations and ability to leach from soil to solution. Pollutant compar isons were made to several different state regulations regarding soil contamination and cleanup. The six most common metals found during this study were chromium (Cr), l ead (Pb), zinc (Zn), copper (Cu), cadmium

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26 (Cd), and nickel (Ni). Concentrations of Cr Pb, and Zn were detected at 100% of the sites. Cu was next with a 94% detection level, then Cd, followed by Ni, with 72% and 67% concentrations, respectively. It was not ed that as a group metals were the most frequently detected runoff related pollu tant identified during this study (Cox et al. ., 1998). When compared to Soil Cleanup Target Levels (SCTLs), of the six most commonly identified metals, only Pb exceeded these parameters at a frequency of 3.5%. For leachability, Pb exceeded criteria at 80% of the sites, followed by Cr in 9%, and Cd in 6% of the samples. In terms of the Sediment Quality Assessment Guidelines (SQAGs), Pb was the most problematic metal, exceeding standards at 39% of the sites. Pb, Cu, Zn, and Cd were also identified in 22% to 11% of all samples screened. The majority of contaminants detected a bove cleanup criteria during this study were distributed within the first 2.54 cm of soil, except for Pb, which was identified exceeding cleanup criteria at a depth of 20.32 cm. Information obtained from the 1995 study a nd 1998 final report indicated the need for future studies in soil contamination to develop adequate di sposal guidelines. Environmental protection values, such as those established in the SCTLs, and the SQAGs, are currently applied indirectly when considering stormwater soil disposal. It was also noted that past r ecommendations for soil removal based on accumulation rates did not address variable loadi ng rates due to land use category. It suggested more data be accumulated to develop guidelines for proper soil removal periods. While the main intent of this past research was to evaluate so il contamination for disposal purposes, the concentrations and frequencies of several c ontaminants warrant further investigation into the potential of acute and chronic effect s on organisms from stormwater soils.

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27 Criteria Used in Metal Contamination Analysis Due to the absence of direct regulator y requirements for metal concentration build-up in stormwater basin soils, evalua tion of contaminant levels was accomplished through applying several state regulations and guidelines that indirectly impact stormwater maintenance facilities. To eval uate sediment contamination in relation to human and wildlife concerns, SCTLs refe renced in Chapter 62-777, F.A.C. were observed. In addition, SQAGs developed for Floridas coastal wa ters were used to evaluate metal concentrations in relation to th e aquatic environment. Both sets of these comparative values have been used in ot her studies similar in nature to the NATL stormwater basin evaluation. In addition to regula tory standards, baseline concentrations for trace elements in Florida surface soils established by Chen et al. .(1999) were reviewed. Chapter 62.777 F.A.C. Contaminant Cleanup Target Levels Values obtained in this chapter apply dir ectly to sites governed by the terms of a brownfield site rehabilitati on agreement, pursuant to Chapter 62-785, F.A.C., and to contaminants of concern defined under Chapter 62-770, F.A.C., Petroleum Contamination Site Cleanup Criteria, Ch apter 62-782, F.A.C., Dry-cleaning Solvent Cleanup Criteria, in addition to the trea tment of soils permitted under Chapter 62-713, F.A.C., Soil Treatment Facilities (Florida Department of Environmental Protection, 1999). It should be noted th at these values are intended for application only to sites governed under the above referenced chapters While they do not reference stormwater soils, they are sometimes applied, however, wh en stormwater basin soil disposal options are being considered (Livingston and Cox, 1995).

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28 SCTLs for metals established in Chapte r 62.777, F.A.C., have been separated into two categories (Table 1). Each category de fines differing levels of health protection based on exposure criteria, such as dermal c ontact, ingestion, and i nhalation. In addition, variables such as body weight, exposure fre quency, and exposure duration were all used when developing the model for acceptable risk-based concentrations of contaminants in soils. The first, and more stringent of the two categories are the residential-based exposure values. The greater le vel of protection for these come s from their availability of access to the general public, such as children. The increased protection factor is based on the fact that these sites are open to the public, and can be frequented by individuals with no limited access. For this study, these values were applied when considering exposure of contaminants to both human and wildlife communities in the area. The second category, defined as commerci al/industrial-based exposure values, offers a lesser degree of protection. However, this is based on the assumption that access to commercial sites is limited to the public and exposure times could be regulated for individuals working in these areas. Table 1. Soil clean-up target levels (SCTLs) for contaminated soils Contaminant Cadmium751300 Chromium210420 Copper11076,000 Lead400920 Nickel11028,000 Zinc23,000560,000 Residential Exposure (mg/kg)Commercial Exposure (mg/kg)

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29 Soil Quality Assessment Guidelines (SQAGs) SQAGs are biological-effects based guidelin es developed for FDEP to be used as a tool when studying soil–associated contamin ants in coastal environments. Data have been collected by FDEP for over a decade and analyzed to establish these guidelines, which identify ranges in concentrations of contaminants that have low to high probabilities of causing adverse biological effects to aquatic organisms (Florida Department of Environmental Protection, 2000). An absolute determination of detrimenta l biological effects cannot be based solely on the evaluation of SQAGs. These guidelines should be used in conjunction with other available data, due to several limitations. Specifically, these guidelines represent pollution potential only. Cause and effect re lationships are not inferred when comparing these guidelines to other chemical data. A nother limitation is the i ssue of bioavailability. Factors that can control metal sorption such as total organic carbon (TOC) are not equated when deriving SQAG ranges. A third li mitation is that the data used to develop the guidelines were collected from acro ss the country. How well these guidelines represent all Florida soils is uncertain. In addition, these va lues were derived for coastal water soils, not freshwater. However, with guidelines for freshwater systems currently under development, the SQAGs for coastal envi ronments have been indirectly applied in past studies. While the use of SQAGs in contamination studies may have limitations, their value as contaminant indicators is th e first step in determining possible areas of concern relating to soil quality. To determine pollution potential from th e SQAGs, ranges have been established which divide each contaminant of interest in to three different categories (Table 2). The first, and lowest pollution potential range is considered the no effects level. At these

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30 concentrations the contaminants rarely or never are associated with adverse biological effects to aquatic organisms. The second range is classified as the threshold effects level (TEL). It is at this minimal concentration that contaminants frequently cause adverse biological effects. Last of all, we have th e range of highest pollution potential, classified as the probable effects level (PEL). When concentrations of pollutants exceed the minimum value of this range there are usually or always adverse biol ogical effects on the aquatic community exposed. Table 2 Soil quality assessment guidelines for heavy metals in study. Values established in the Florida Department of Environm ental Protection Soil Quality Assessment Guidelines for Coastal Sediments ContaminantNo Effects LevelThreshole Effect LevelProbable Effect Level (mg/kg)(mg/kg)(mg/kg) Cadmium0 0.6750.676 4.20> 4.20 Chromium0 52.252.3 159.9> 159.9 Copper0 18.618.7 107.9> 107.9 Lead0 30.130.2 111.9> 111.9 Nickel0 15.815.9 42.7> 42.7 Zinc0 123.9124 270.9> 270.9 Baseline Concentrations for Trace Metals in Florida Soils When comparing contaminant levels of trace metals to actual field values, it is important to distinguish between natural-o ccurring metal concentr ations and those that may be attributed to anthropogenic sources. Years of contaminant inputs to soil makes establishing true background c oncentrations difficult (Chen et al. 1999). Work conducted by Chen et al. (1999) evaluated the use of base line concentrations to estimate natural levels of trace metals in Florida surface soils.

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31 It was determined that the use of baselin e concentrations better represented the variation in trace metal conc entrations, than did using the observed ranges. Log transformations of the values minimized the few high concentrations, which could distort the overall range (Chen et al. 1999). These baseline concentrations were used for comparison in this study (Table 3). Table 3. Baseline concentration for Florida Surface Soils (Chen et al. 1999) MetalCalculated Baseline Concentration (mg/kg) Cd0 0.33 Cr0.89 80.7 Cu0.22 21.0 Ni1.70 48.5 Pb0.69 42.0 Zn0.89 29.6 Metals Stormwater has been shown to contai n a number of different contaminants, dependent upon the watershed collection area, that may pose health and environmental threats to exposed communities. Metal concentr ations in stormwater have been identified through studies to be the most commonly de tected contaminants at many locations. Metal concentrations at si tes may be a mix of natural occurrence and anthropogenic inputs. The process of mass loading metals on soils already containing natural trace metal concentrations could lead to the accumulation of potentially toxic levels of contamination. In addition, th e potential for human, animal, and aquatic organism uptake and storage of metals internally could crea te long-term health concerns. To assess concerns relating to heavy metal exposure, each contaminant should be evaluated on its potential to affect human and environmenta l health. The following information on metal

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32 toxicity was obtained through the Agency fo r Toxic Substances and Disease Registry (ATSDR) website, located at www.atsdr.cdc.gov (ATSDR, 2001). Cadmium (Cd) Cd is an element that can be found natura lly in the earths crust or used in a variety of applications, including manufactur ing of batteries, paint pigments, metal coatings, and plastics. Additionally, the bur ning of fossil fuels can contribute to the presence of Cd in the environment. Cd can enter natural systems through deposition from air emissions, as well as through leaching or washing of contaminated sites. Sediment contamination from Cd occurs through sorption to organic matter, a nd through co-precipitation with iron, Al, and Mn-oxides. It binds strongly to soil particles, not breaking down in the environment, but rather changing forms. Exposure to Cd occurs mainly through inha lation of contaminated air, ingestion of contaminated food sources or through contamin ated water supplies. The bio-availability of Cd in sediments is dependent upon pH redox potential, water hardness, and the presence of other complexing agents. Studie s have shown that animals exposed to high doses of Cd experienced lung disease and stomach disorders. Cd ability to remain in the body for a very long time allows for levels to build up, even if e xposure concentrations are low. Aquatic organisms exposed to Cd have shown various effects, including acute mortality, reduced growth, a nd inhibited reproduction. It is unclear whether human exposure to Cd will result in similar diseases when exposed to equal levels as in animal studies. Exposure to Cd through dermal cont act has no known effect in either humans or animals.

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33 Recommendations to protect public he alth have been made by several governmental agencies. The United States Environmental Protection Agency (USEPA) has established limits for Cd in drinking water set at 0.005 parts per million (mg/L). The United States Food and Drug Administration (USFDA) allows up to 15 parts per million (ppm) in food colorings, while the Occupatio nal Safety and Health Administration limits workplace air to 100 ug/m3 as Cd fumes, and 200 ug/L as dust particulate (ATSDR, 2001). Additional guidance concentrations have been derived for use with the SQAGs, and SCTLs. SQAGs have established a TEL of 0.68 mg/kg, and a PEL of 4.2 mg/kg. The SCTLs for exposure limits are set at 75 mg/kg for residential exposures, and 1300 mg/kg for commercial exposures. Chromium (Cr) Similar to Cd, Cr is an element that can be found occurring naturally in the environment, as Cr(III), or as a byproduct fr om various industrial processes as Cr(0), or Cr(VI). Processes involving the use of Cr include st eel production, paint and dye production, leather tanning and wood preservation. Cr enters the environment through deposi tion from air emissions and leaching at contaminated sites, mainly in the Cr(III) a nd Cr(VI) forms. Once introduced to a natural system its fate depends upon the form at whic h it enters. In aqua tic systems Cr(VI) tends to be very soluble, not readily sorbed to particulate matter. However, as anaerobic conditions prevail, Cr(VI) reduces to Cr(III), a state which can strongly sorb onto organic particulates. Exposure to Cr contamination occurs through inhalation, ingestion, or dermal contact. Inhalation of high levels of Cr(V I) has been shown to cause nasal irritations such as nosebleeds or ulcers. Ingestion of similar levels can cause stomach, liver or

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34 kidney damage, which may result in death. Unlike Cd, dermal exposure to high levels of Cr(VI) may result into skin ulcers. Indivi duals with severe a llergies may experience swelling and redness to exposed areas. Studies have shown Cr(VI) compounds can increase the risk of lung cance r, and the several health orga nizations have labeled Cr(VI) in various forms as a human carcinogen. Additional adverse e ffects to biological communities include death and decreased growth, particular by vegetative species. Fish do not tend to be as sensitive as hum ans to Cr contamination (ATSDR, 2001), Federal regulations have been establis hed by the EPA and OSHA to protect public health from exposure to high levels of Cr. EPA recommends Cr concentrations in water not to exceed 0.1 mg/L. In addition to drinking water standards, SQAGs and SCTLs have been derived for contamination and re mediation assessments. Under the SQAGs, a TEL of 52.3 mg/kg and a PEL of 160 mg/kg have been established for aquatic biota protection. The SCTLs for residential and commercial exposures are 210 mg/kg, and 420 mg/kg, respectively. Copper (Cu) Cu is a natural occurring metallic element in crustal rocks and minerals, released during weathering processes. Anthropogen ic sources of Cu include agricultural fungicides, pesticides, sewage treatment effluent, wood preserving, and fallout from industrial sources and coal burning. Cu can enter natural systems through w eathering of minerals, release in air emissions, and through direct exposure as in so il or water treatmen t devices. Inhalation, ingestion and dermal contact are the main pa thways for Cu exposures to many organisms. While Cu is considered an essential micronutri ent, exposure to elevated levels in the air can cause irritations to the nose and mouth. Ingestion of high levels of Cu can lead to

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35 kidney and liver damage as well as stomach di sorders. Dermal exposure to elevated Cu levels can result in an alle rgic reaction or rash in sens itive individuals. There is no indication that Cu exposures can lead to can cer in either humans or animals. However, Cu contamination of aquatic systems may be a ssociated with acute and chronic toxicity in biotic organisms (ASTDR, 2001). Human health concerns from Cu contamin ation have led to the establishment of federal guidelines regulating consumption and workplace exposures. Drinking water standards have been set at 1.3 mg/L. In addition to EPA and OSHA regulations, protective levels have been derived under the SQAGs and the SCTLs. The SQAGs have established a TEL of 18.7 mg/kg, and a P EL of 108 mg/kg. Residential exposure guidelines established for SCTLs has been set at 110 mg/kg, while commercial exposure limits are 76,000 mg/kg. Lead (Pb) Pb is a metallic element that is found in virtually all parts of our environment. While it can be naturally oc curring, anthropogenic sources contribute heavily to its presence. These sources include the bu rning of fossil fuels, mining, and the manufacturing of batteries, metal products and ammunition. The use of Pb in many items such as paints and gasoline has been greatly reduced due to health concerns. Pb can enter natural systems through de position with air particulates or by leaching or washing of contaminated su rfaces. Once Pb comes into contact with sediments, its movement is dependent upon the type of Pb compound and soil characteristics. Pb(II) tends to be the most stable ionic species, and can be found bound to Fe and Mn-hydroxides in addition to clay a nd organic matter. Oxidized sediments tend

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36 to bind closely with Pb, with its rele ase and mobility increasing under reducing conditions. The majority of exposures to Pb occur through ingestion or inhalation. In humans, Pb exposures to high levels ha ve been shown to affect the organs of the body and the central nervous system. Blood disorders and male reproductive problems may also occur. Aquatic organisms also exhibit toxic aff ects from Pb. Plants tend to be less sensitive to exposures than fi sh or invertebrates. While studies involving animals indicate the possibility of Pb to be a carcinogen, there is no evidence to suggest carcinogenic effects in humans. Federal agencies have set regulations to control Pb exposures through ingestion and workplace incidences. Drinking water standards for Pb are set at 0.015 mg/L. Additional recommendations have been made regarding Pb screening programs for children who live in areas determined to be high risk zones (ATSDR, 2001). The SQAGs have derived a TEL of 30.2 mg/kg, and a P EL of 112 mg/kg. SCTLs set exposure limits at 400 mg/kg for residential classificati ons, and 920 mg/kg for commercial sites. Nickel (Ni) Ni is an element found abundantly in the earths crust, prim arily combined with oxygen and sulfur. Ore deposits often contain Ni with Fe or Cu. While Ni is used in a variety of manufacturing a nd industrial industries, the major anthropogenic sources include, fossil fuel combustion, batteries, Ni ore mining, smelting and refining activities, and electroplating (FDEP, 2000). Anthropogenic sources of Ni may enter en vironmental systems as small deposits in air particles, or through the washing and leaching of surfaces containing Ni. As anthropogenic sources are introduced to se diments they become bound as Fe or Mnoxides or they sorb with organic matter. Release of Ni from sediments may decrease

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37 under anaerobic conditions as they form inso luble complexes with sulfides. Human and animal exposures to Ni can be through inhalation, ingestion or dermal contact. Ni is considered a required element fo r maintaining good health, but, exposures to high levels can cause adverse he alth effects. The most severe exposures for humans and animals in terms of health related concerns appear to be through dermal contact and inhalation. Allergic reactions from contact w ith Ni, in the form of skin rashes, are the most common types of health effect seen. Workplace exposure to air particles containing Ni compounds have been linked to lung as nasa l cancers. In terms of adverse effects on aquatic organisms, increased mortality rate s, decreased growth and avoidance reactions have been observed. With certain Ni compounds determined to be carcinogenic, federal agencies have established recommendations regarding i ngestion on water containing these compounds (ATSDR, 2001). In addition to drinking water standards of 0.04 mg/L, occupational exposure levels have also been established to reduce concerns from inhalation. For the protection of aquatic organisms the SQAGs have derived a TEL of 15.9 g/L, and a PEL of 42.8 g/L. SCTLs have been determined to be 110 ug/L for residential considerations, and 28,000 ug/L at commercial sites. Zinc (Zn) Zn is an abundant element, found in air, so il, and water. As a crustal element it is present commonly as a sulfide, carbonate, or silicate ore. Zn has a number of different production uses, including dry cell batteries, rust preventatives, and as a mixture with other metals to form alloys. Release of Zn into the environment can occur through natural processes. Anthropogenic inputs from air deposition and leaching also contribute to its presence.

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38 Much of the Zn entering the environment stay s bound to soil with Fe and Mn-oxides, clay minerals and organic matter. Adsorption rate s of Zn have been determined to be pH dependent, showing a decrease in aquatic syst ems with pHs below 6. Sorption to organic matter in fine grained sediments is c ontrolled by reducing conditions, which form insoluble sulfides (FDEP, 2000). Health concerns over exposure to Zn arise from ingesting contaminated food or water supplies, or from breathing aerosolized Zn particles near manufacturing plants. Zn is an essential element to the diet of hum ans, requiring an appropriate balance to be effective. Since our bodies require Zn, low i nputs to our systems can be just as harmful as exposures to high levels. Ingestion of high levels of Zn may lead to short-term stomach and blood disorders and possibly panc reas damage. Inhalation of Zn at high concentrations may cause lung irritations and body temperature fluctuations on a shortterm basis. Long-term effects for Zn inha lation have not been determined. Affects on aquatic organisms appear to be minor as they can experience a wide range of sensitivity to Zn exposure. Zn is currently not lis ted as a possible carcinogen (ATSDR, 2001). Federal agencies have established reco mmendations for human exposures to Zn contamination through drinking water of 0.005 mg/L, and workplace exposure guidelines. To protect aquatic organism s, the SQAGs have recommended a TEL of 124 mg/kg, and a PEL of 271 mg/kg. SCTLs have been established at 23,000 mg/kg for residential sites, and at 560,000mg/kg for commercial cleanup designations. Metal Attenuation in Stormwater retention Basin Sediments Stormwater runoff has been shown to contain various contaminants dependent upon the input source. Metals, being one va riety of stormwater contaminant, can

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39 accumulate in stormwater soils depending upon soils characteristics, such as pH, percentage of organic carbon, percentage of Fe and Mn oxides and existing metal concentrations. As vegetation within stormwater systems decays, organic matter can accumulate. Igloria, et al. (1997), studied the effects of natural organic matter (NOM) as a source for attenuation of metals in stormwater, and as a facilitator of metal transport within stormwater basins. Their conclusi ons were that the addition of NOM did not enhance metals transport, but in fact, th e high affinity of the NOM to the soil in combination with the metals attraction to the NOM decreased the metals mobility (Igloria, et al. 1997). Another study evaluated Cu a nd Cd distribution in forested soils and determined that organic matter or Fe and Mn-oxides were responsible for immobilizing Cu, and that Cd attenua tion was also dependent upon metal-oxide relationships (Keller and Vedy, 1994). Similar results for metal deposition in re lation to organic matter were reported by Walker and Hurl (2002), and Goulet and Pick (2001). Metal distri bution has been shown dependent upon not only its association with or ganic matter, but with stormwater basin design, such as depth and plan ted vegetation. Stormwater basins with shallow water column depths may allow for a larger distri bution pattern due to wa ter turbulence stirring and moving sediments (Goulet and Pick, 2001). In addition, vegetation can act as a plug, slowing the velocity of stormwater inflow and reducing the effects from wind on shallow surfaces in retention basins. Metal uptake within stormwater retention ba sin soils may play a large part in the spatial distribution at which contamination is detected. In vegetative wetlands, Cd, Cu, and Zn concentrations have been measured the highest in 0 – 5 cm samples, while Pb

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40 concentration was shown to increase to a depth of 55 cm (Cheng et al. 2002). A study conducted by Kao et al ., (2001) compared contaminant removal rates from influent for both vegetative and unplanted soils surfaces. In a wetland setting both Pb and Zn concentrations decreased by 95% and 92% respect ively, from stormwater inflow to water quality exiting the system. Although lower, the unplanted treatment basin showed an effluent contaminant removal rate of 32% for Pb, and 40% for Zn (Kao et al. 2001). Typically redox potential may play a part in the partitioning of metals with stormwater basin soils. In soils where th e redox potential is gr eater than 100 mV, most metals present within pore water will eith er precipitate as meta l-oxides or adsorp to organic matter. As redox potential decreases to between 100 mV and mV, reduction of metal-oxide can resu lt in the release of dissolved metal back to solution. If enough organic matter is present the metals may still adsorb, otherwise they may be transported with the water column thr ough sedimentation. Below mV, metal-soil relationships are developed strictly thr ough reactions with monosulfides and organic matter adsorption (Goulet and Pick, 2001). Clearly studies have been completed wh ich indicate relationships between soil characteristics and their role s in metal attenuation. Sedi ments within the stormwater retention basin at the NATL are no different that many of these study sites in terms of organic content, contaminant input sources a nd other variables. Ignoring the possibility of metal accumulation to potentially hazardous levels within sediments in the SEEP or any other stormwater retention basi n could be a dangerous oversight.

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41 OBJECTIVES In the past, urban stormwater retention ba sins served the purpose of collecting and treating stormwater runoff before it infiltrat ed or discharged into a water resource. Basins were not created nor intended to be used for recreational purposes or to be considered quality habitats for wildlife or a quatic organisms. Access to these areas may have been limited through locked gates or minimized by undesirable site conditions, such as dry retention ponds. The situation is ch anging with the integration of wetlands into stormwater basins emerging as a method of enhancing treatment to improve the quality of discharge. With the development of the stormwater basin at the NATL focused on increased opportunities of study for students and faculty at UF, in addition to creating a diverse habitat for wildlife, exposure to contaminants commonly found in urban stormwater water runoff could occur through ingestion, i nhalation, or dermal contact. Regulatory considerations focus mainly on environmental protection through water quality improvement, with little emphasis on soil quality. The lack of regulatory guidance for st ormwater soil contamination played an important role in the development of the obj ectives for this study. Both the ability to provide information that could be used in de termining the direction of future stormwater studies at the basin, and to specifically address contamina tion concerns related to the usage of the basin as a research site and as a wildlife habitat, were desired outcomes.

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42 Objective 1 – Evaluation of Current Soil Conditions for Future Studies One anticipated study for the stormwater ba sin is to determine the efficiency and effectiveness of the wetland design in pollutant removal from stormwater. Soils will play an integral part in this process. No b ackground levels of contamination or other soil quality parameters exist for so ils within the retention basin. By establishing these levels, future studies can compare parameters sim ilar to those that have been documented through this research. Objective 2 – Comparison of Current Metal Con centrations in Basin Soils to Soil Target Cleanup Levels The University of Florida will continue to use the basin as a research site. With the availability of contamin ant exposure to students worki ng in the area, current metal concentrations will be compared to esta blished SCTL concentrations. In doing so, possible problematic areas can be identifi ed and addressed accordingly. Additionally, these values may be applied to eval uate potential contamination concerns for wildlife. Objective 3 – Comparison of Current Metal Con centrations in Basin Soils to Soil Quality Assessment Guidelines As the basin ages, a diverse aquatic commun ity is expected to thrive within the wetland zones. The stability of this aquatic community relies upon its surrounding environment. The SQAG’s establish concentr ation ranges for contaminants to evaluate the possible adverse health effects th at these ranges may pose upon the aquatic community. Areas of concern can be delin eated and marked for further studies in bioavailability and accumulation.

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43 As previously stated, the objectives of this research were set to provide the University of Florida with accurate info rmation on existing soil quality in the NATL stormwater retention basin. Information obt ained through this research can be used in determining the future direction in which the management and usage of the basin may proceed.

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44 MATERIALS AND METHODS Site Description The study site was the retention basin at the Natural Area Teaching Lab (NATL), located on the campus of the University of Florida. The NATL is located at the southwestern corner of the University campus (Figure 7). This location affords individuals an excellent opport unity to conduct field studies of multiple ecosystems. The outdoor research facility consists of a total of 18.62 ha. Lying within this property are three upland communities; hammock, upland pine, and old field succession, as well as thriving wetland communities surrounding both a small sinkhole and the ecologically enhanced retention basin (Figure 8). Figure 7. Location of Retention Ba sin at Natural Area Teaching Lab

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45 Figure 8. Layout of Natural Area Teaching Lab Nine departments in four colleges have dedicated studies involving areas of the NATL (Wetlands Club, 2001). Included al so, is the Wetlands Club, which has coordinated with the NATL Advisory Committ ee and the UF Physical Plant to develop what has now come to be known as the Stormwater Ecological Enhancement Project (SEEP). The idea for the SEEP was to create a multi-stage wetlands designed not only to treat and dispose of urban stormwater runo ff, but to create desirable conditions that would attract and sustain various wildlife species. Additional benefits derived from the development of the SEEP project include: 1) An increase in the overall aesthetics of the NATL N

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46 2) Expanding research opportunities to indi viduals interested in wetlands study 3) Affording students as well as the public the chance to study wetland systems in a formal class setting or, by independent viewing. The stormwater basin is a 1.21-hectare re tention pond, which collects runoff from a number of sources existing w ithin the 40-hectare watershed that it serves. Natural runoff from the surrounding undeveloped areas becomes mixed with runoff from the watershed’s impervious surfaces that is transported through an underground network of piping (Figure 9). Figure 9. Photograph of stormwater runo ff collection area covered with debris. Of the approximately 41% impervious su rfaces existing within the basin, the most intensive and probable source for pollutant transport comes from parking surfaces,

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47 particularly an 1100-space commuter lo t to the north, and parking for the Entomology/Nematology building to the east (Figure 10) Figure 10. Natural areas and parking surf aces draining to the retention basin. A) Transition area from old field succession to up land pine. B) Southerly view of commuter parking lot and garage. C) Entrance to Entomology & Nematology building located to the east of the stormwater retention basin. The basin was originally constructe d in 1988 with permitted storage capacity designed to accept and dispose of 18,855 m3 of stormwater runoff through infiltration and evaporation. The collection period based on a 100-year flood even t based over a 24-hour A) B) C)

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48 span. Urban development within the watershe d required that the basin be redesigned in 1990 to handle an additional 12,221 m3 of runoff, bringing its total capacity to 31,076 m3. Design of the basin was traditional in it s approach. The lack of surface water discharge negated the use of a detention system to improve water quality of the disposed stormwater, allowing for stormwater retenti on to be the driving force in design. With retention basins that do not discharge to surface waters, there is greater emphasis on storage of runoff as opposed to enhanced stor mwater treatment. This particular design was typical of a standard retention basin, dependent upon evaporati on and percolation to dispose of stormwater on-site. Uniform slope s lined the basin to the north, south, and east, while the west side was contoured to a natural depressional area. Stormwater entered the system through four major collecti on sites and was guided to the flat center of the basin for disposal (Figure 11). With the concept of the SEEP, basin de sign became more ecologically enhanced by the addition of berms in the northern and southeastern portion of the retention basin and by creating deep water infi ltration ponds to the south (Fi gure 12). Functionality of the basin shifted from a pure retention type system to a system incorporating retention theory, using both vegetation and increased wa ter detention periods in conjunction with on-site disposal.

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49 Figure 11. Original design of stormwater re tention basin before enhancement project began. A) Stormwater inlet collecting di scharge from commuter lot and garage. B) Stormwater inlet collecting runoff from Entomology & Nematology building. C) Stormwater inlet collecting runoff from be hind and adjacent to Florida Museum of Natural History, and the Performing Arts Cent er. D) Stormwater inlet collecting runoff from unpaved parking lot and grass swales be hind and to the west of the Entomology and Nematology building. A)B) C) D) N

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50 Figure 12. Diagram of the retention basi n post enhancement that occurred in 1998. Berms added to the north and southeast s ections of the basin increase and direct stormwater flow. The two infiltration ponds to the south allow fo r increased settling of stormwater particulate matter and evaporation. Berm Berm Deep Water Infiltration Ponds N

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51 Sampling Locations When developing a soil sample scheme for the stormwater management system, the first step was to separate the ba sin into individual cells Each cell could be evaluated for contamination and comparativ e values would exist between each region. The existing configuration of the stormwater basin dictated a division of three cells for evaluation (Figure 13). Figure 13. Breakdown of the sample cells inside the stormwater retention basin. Cell 1 Cell 2 Cell 3 N

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52 Cell one represented the forebay, extending from the north end of the basin to the northern berm, including three of the four stormwater inflow pipes. Cell two encompassed the remaining stormwater inflow pipe located at the southeastern corner of the basin and extended to the southernmost section of the berm bordering cell one. Cell three, the final section of the stormwater ma nagement system, consisted of the two deepwater ponds. Cell one was further separated into thre e sections for evaluation. The first section, located in the north western corner of the stormwater management system, contained two of the three stormwater inflow pipes, which drained the entire impervious surface of the major parking area. Flow patterns were established through observed channeling from the inflow areas, and five locations, A1 through A5, were sampled (Figure 14). The emphasis on these sites was to determine soil quality from the stormwater inflows to the center of the forebay. All the sites chosen in this area consisted of soils that had been left undisturbed during re-contouring. The second section of cell one consisted of a single point just west of the stormwater inlet pipe located in the northeaste rn part of the basin. This point, labeled A6 (Figure 14), represented undisturbed basin so ils to the east of center in the forebay. Flows in this area were made up of sheet flow from a two-lane road and parking lot runoff from the front section of the Entomolgy/Nematology building. The third section of this cell was the cen ter of the forebay. The majority of this area, represented by sites A7 through A12 (F igure 14), was scraped during the 1998 recontouring. However, site A9, located in the no rthern part of this section appeared not to have been disturbed based on the surface textur e, and from a visual inspection of the site

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53 after the re-contouring. Sample site locations within this s ection represented contaminant and suspended particle movement from th e stormwater inflows through the forebay, exiting from the weir into cell two. In cell two, five sample locations were chosen for evaluation. Sites B1, B2, & B3 (Figure 14) were located south of the weir in an area that had been scraped in 1998. This represented water flow movement as it ente red into cell two, dispersing either south, southeast, or southwest. A major decision for choosing these points is that soil quality can be compared between their locations and si te A7 to evaluate the efficiency of the forebay in pollutant removal. Site B4 was situated in the direct flow path coming from the remaining stormwater inlet pipe to the sout heast of the basin. Water flow in this area was channeled towards the d eep-water infiltration ponds by the southern berm and several small elevated mounds. The soil surf ace in this area had again been scraped in 1998. The remaining site in cell two, B5, was located in the western portion of the basin. This area had not been re-contoured in 1998 and was the only section consisting of original undisturbed soil in cell two. In cell three, two locations were chosen for evaluation (Figure 14). Site C1 was located in the center of the first deep -water pond, while C2 was centered in the southernmost deep-water pond. Due to the n eed to restructure the infiltration ponds when creating the SEEP, the entire area within this cell had been re-contoured. An additional sample, D1, was taken from outside the stormwater management system to act as a control site. This site was located to th e west of the system, directly behind the Performing Arts Center.

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54 Figure 14. Location of sample sites in the stormwater retention basin. A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A2 A1 B1 B2 B3 B4 B5 C1 C2 D1 N 10m

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55 Secondary consideration was given to samp le site locations for the evaluation of soils left in place from the original construction of the stormwater management system, as compared to soils from the recently re-c ontoured areas (Figure 15). Eight of the 19 sites within the basin were located in area s left undisturbed, allowing for evaluation and the creation of baseline data for undi sturbed and scraped areas (Table 4). Figure 15. Sample site locations for the stor mwater management system. Areas outlined in red contain soils left undisturbed during the 1998 re-contou ring of the system. A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A2 A1 B1 B2 B3 B4 B5 C1 C2 D1 N10m

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56 Information gathered from the 20 sample sites selected has been used to set baseline data for future studies at this site. From the locations selected, a good representation of the extent of contamination within the ba sin already can be seen, and some assumptions made based on current soil quality conditions. Table 4. Sample site status for each cell evaluated. Cel lSi te Locati onScraped / Undi sturbed A1Undi sturbed A2Undi sturbed A3Undi sturbed A4Undi sturbed A5Undi sturbed A6Undi sturbed A7Scraped A8Scraped A9Undi sturbed A10Scraped A11Scraped A12Scraped B1Scraped B2Scraped B3Scraped B4Scraped B5Undi sturbed C1Scraped C2Scraped 2 3 1

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57 Field Procedures Samples were taken using the guidelines set forth in the Comprehensive Quality Assurance Plan of the Southwest Florida Wa ter Management District, (1993). All soil samples were collected with shovels and stai nless steel equipment. Soils surfaces, that came into contact with steel equipment, were removed through the use of non-metallic spatulas. All loose debris not affixed with the soil was remove before sampling. Coring devices and spatulas were cleaned with di stilled water after each core sample was completed. Once obtained, samples were stored on ice until transfer was complete to the University of Florida Environmental Pedology lab. Composite samples of 4 to 7 cores within an area of 0.25m for each site were analyzed at depths of 0-5cm and 5-10cm. In all, 20 sites were selected, bringing the total number of analyzed soil samples to 40. Of the 20 sites, 19 (A1 – A12, B1 – B5, C1 – C2) were located inside the stormwater management system, with one (D1) being taken outside the system to represent background data. Laboratory Procedures All samples were prepared by first ai r drying and then running through a 2.0 mm sieve before ball milling to achieve a homogene ous mixture. Samples were analyzed for heavy metals, organic carbon content, orga nic matter content, pH, and particle-size distribution (Table 5).

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58 Table 5. Sediment analysis and methods used in study Metal Analysis The heavy metals selected for analysis were chosen based on their rank as the most common determined in urban st ormwater runoff during a 1995 DEP study of contamination in 87 stormwater ma nagement facilities (Livingston, et al. 1995). The specific metals analyzed were Cd, Cr, Cu, Pb, Ni, and Zn. A one-gram sample digestion of dried soil was completed at the UF Soil Environmental Pedology Lab using EPA Me thod 3050, as directed under the standard operating procedure guidelines set by UF Profe ssor, Dr. Lena Ma. Sample solutions were then placed in standardized containers and sent to the Analytical Research Laboratory, located on the University of Florida campus for analysis by an Inductively Coupled Plasma (ICP) analyzer. Minimum detection limits for all metals was 0.01 mg/kg, with the exception of Cr, which was 0.04 mg/kg. Organic Carbon Content The organic carbon analysis was comp leted using the Walkley-Black method. Samples which exceeded the acceptable range for percent organic carbon using this method were run again by lowering the samples size to 0.125g or 0.025g, making the SOILANALYSIS METHOD Metals (Cd, Cr, Cu, Ni, Pb, Zn) Di g estion EPA 3050 Analysis Inductively Coupled Plasma (ICP) Organic Carbon ContentWalkey-Black Method (Soil Survey Laboratory Methods Manual, 1996) Soil Organic MatterLoss On Ignition (Broadbent, 1953) Particle Size DistributionPipette Method (Day, 1965) Soil pHSoil Survey Laborato ry Methods Manual (1996)

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59 appropriate calculations to obtained percent organic carbon. While the Walkley-Black method works well on soils with less than 6% organic matter, the loss on ignition method better suits soils with organic matter conten ts greater than 6% (Agvise Laboratories, 2002). Organic Matter Content To determine organic matter content, the loss on ignition method, as described by Broadbent (1965), was used. Three grams of soil were placed into 20 ml crucibles and brought to a temperature of 105C for 2 hours. Samples were then weighed to +0.01grams, then brought to a temperature of 500C for a period of eight hours. After being allowed to cool in a moisture-free environment using a desiccator, the samples were again weighed and recorded. To determ ine the percent organic matter the following equation was used:% Organic Matter =(Sample Weight 105C Sample Weight 500C x 100) / Sample Weight 105CParticle-Size Distribution Particle-size distribution was determined on the samples using the pipette method as described by Day (1965). Since the cl ay content of these samples was unknown, a sample weight of 25.0g (+/0.1g) was used. Values obtained were compared with a soil texture classification triangle to determine the appropriate textural class. pH Analysis Stormwater retention basin soils were analyzed for pH using the method described in the Soil Survey Laboratory Me thods Manual (1996). Twenty five grams of soils was analyzed using both water and potassium chloride.

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60 Statistical Methods Statistical analysis was done using the Number Cruncher Statistical System (NCSS) data analysis software program. Linear regression analysis was conducted to examine relationships for a ll dependent variables (metals) to the independent variables, pH, organic carbon, or ganic matter, and percent clay content. Estimating Metal Loading Rates Analytical data presented in this thesis has indicted that metal concentrations at certain locations within the stormwater rete ntion basin exceed seve ral indirect guidelines for soil clean-up and quality assessments. At what point soils within this and similar basins reach potentially toxic levels is unc lear, without regulatory requirements for periodic soil monitoring. If certain inform ation is known about a particular basin, then estimates can be made as to a particul ar concentration of contaminant loading. For this study, water quality data was no t collected, ruling ou t the option for site specific loading rates. There are, however, ways to determine rough estimates of metal loading based on computer-generated programs. One such program is the Long-Term Hydrological Impact Analysis (L-THIA) GI S based model. This analysis uses established hydrologic data, based on a long-t erm average in combination with defined land use and soil classes to establish stormwat er runoff rates. When site specific data relating to stormwater metal c oncentrations is not used with this model, non-point source pollutant averages established by the Texa s Natural Resource Conservation Commission (TNRCC) becomes the default. Arial photography was used to create a land-use layer for the SEEP watershed. The land use and the soils layer will be combin ed with 20-years of local rainfall data to

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61 generate curve numbers and runoff volumes on a one-meter cell grid. L-THIA then averages these volumes and calculates the average annual runoff volume for each of the one-meter cells in the drainage basin. Th ese volumes are summarized for each land use class and combined with runoff coefficients for each metal based on those land use classes. The total average annual loadi ng of each metal on the SEEP can then be calculated. These loading rates can be used to place in context the concentrations of metals found in SEEP soils.

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62 RESULTS The initial objective of this study was to analyze curr ent soil conditions within the SEEP located at the NATL. Since limited soil data exists for this area, evaluating parameters such as organic carbon content, organic matter content, pH, and particle-size distribution may lay the foundation for estab lishing baseline standards for future studies at this site. Urban development of adjacent land within the watershed has required improvements and upgrades to the stormwater basin, altering soils from their original pedogenic stages. Soil dating back to the init ial construction of the basin indicate soils not representative of what can be identified today. Just as important as the altering of soils within the basin for stormwater runoff collection, are the effects that outside inputs carried in stormwater can have on the environmental quality of the system. Pollutants, such as heavy metals in stormwater runoff, may interact differently in so il depending upon soil characteristics. While it is not uncommon to detect vari ous heavy metals in soils through either natural deposition or anthropoge nic processes, concentrati ons should be maintained at levels acceptable to the environment. Meta l concentrations of the soils inside the stormwater retention basin were compared to baseline concentrati ons for Florida surface soils established by Chen et al, (1999). Additionally, indirect comparisons were made with the screening levels referenced by the SQAGs, and the SCTLs.

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63 Organic Matter Content Soils within the stormwater basin were analyzed for percent organic matter at both 0-5cm and 5-10cm depths (Figure 16). The results indicated the highest organic matter values in cell 1, within the heavily vegetated northwestern corner of the wetland basin, sites A1 through A5. At these loca tions, percent organic matter ranged from 2.7% to 22% in the upper 5cm samples with an average of 11.3%. The 5-10cm samples ranged between 1.7% and 21%, averaging 7.7%. Th e remaining seven sites in cell one ranged from 2% to 7%, averaging 4.5% in the upper samples, and from 1% to 5.3%, averaging 3.9% in the 5-10cm samples. In cell 2, percent organic matter ranged from 5.1% to 7.1% in the 0-5cm samples with an average of 6.0% with in the cell. The 5-10cm samples ranged from 5.1% to 7%, averaging 5.7%. Four of the five sites evalua ted in this cell had been previously scraped during the 1998 re-contouring of the stormwater basin. Excavation at these sites had removed what little sandy deposits that may have been present, exposing the argillic horizon to the surface. Samples taken in cell 3 were limited to two locations, C1 and C2, both scraped during 1998 construction and rede sign of the basin. Percent organic carbon in the 0-5cm samples was 11% and 8% respectively, and 7% and 8.3% in the 5-10cm samples. The slightly higher averages for th is cell in relationship to cell 2 may be explained by a thin 2 cm biomat that had formed in the dry pond region. Additional analysis for organic matter content was completed on the control sample located outside the basin, site D1. At this location, the upper limit sample had a concentration of 3.6% organic matter, and th e lower sample depth was 2.6%. A complete list of organic matter contents for all of the sample locati ons are shown in appendix C-4.

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Cell 1Cell 2Cell 3 0 5 10 15 20 25 A1A2A3A4A5A6A7A8A9A1 0 A1 1 A1 2 B1B2B3B4B5 C1C2 Site Location 0-5cm 5-10cmFigure 16. Percent organic matter in soils within the stormwater retention basin.% Organic Matter 64

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65 Organic Carbon Content Quantitative limitations of the WalkleyBlack method created a data gap for several sites where organic ca rbon content was above the upper limits of detection (6%). Specifically sites A2, A3, & A5 could not be evaluated. For the remainder of the basin, percent organic carbon ranged from 0.11% to 4.19% with highest values in cell 1. There were five sites within cell 1 that had a percentage greater than 1%; site A1(0-5cm) 1.5%, site A4(0-5cm) 2.3% and (5-10cm) 1.1%, site A6(0-5cm) 4.1%, site A10(0-5cm) 3.5%, and site A11(0-5cm) 4.2%. There was only one other site where percent organic carbon exceeded 1%, which was C1 (0-5cm) at 1.7%. At the control site, percent organic carbon was calculated to be 0.78% in the in the 0-5cm sample, and 0.75% in the 5-10cm sample. The higher than expected pe rcentages of organic carbon determined to be present in these soil samples, may indicate complete oxidation of organic material was not have been achieved. Thus, values obtained for percent organic carbon may be considered marginal quantitative data at best. A comple te list of percent orga nic carbon results are in appendix C-4. Soil pH Soil pH was analyzed in both water and potassium chloride for all the sample sites. The results for water analysis and presented in this study (Figure 17). For this analysis, four locations, incl uding the northwestern corner of cell 1, the remainder of cell 1, cell 2, and cell 3, will be separated for discussion. In the northwestern corner of cell 1, the pH ranged from 7.3 to 8.3 in the 0-5cm samples. The 5-10cm samples had a pH range of 7.2 to 7.8. The pH values in this section were higher than in any other part of the basin. A possible source of this pH

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66 increase could be coming from limestone partic ulates that have been washed into the cell from road runoff. In the remainder of cell 1, the 0-5cm samples had a pH range from 5.9 to 7.2. The 5-10 cm samples had a pH range of 5.5 to 6.8. In cell 2, the 0-5cm samples had a pH from 5.1 to 7.1. The 5-10cm samples had a pH range of 5.1 to 7.0. The 2 sites in cell 3 had a pH range of 6.7 to 7.0 in the 0-5cm sample, and a range of 5.3 to 6.8 in the 5-10cm sample. The pH for the control sample was 6.1 in the 0-5cm depth, and 6.2 in the 5-10cm sample. The data for pH can be found in appendix C-4.

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0 1 2 3 4 5 6 7 8 9 A1A2A3A4A5A6A7A8A9 A1 0 A1 1 A1 2 B1B2B3B4B5 C1C2 Site Locations pH 0-5cm Sample 5-10 cm Samples Cell 1 (NW Section) Cell 1 (Center & NE Section) Cell 2Cell 3 Figure 17. Soil pH at locations with in the stormwater retention basin.67

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68 Particle-Size Distribution Percent sand, silt, and clay were determ ined and compared to the soil textural triangle to establish a major texture class for each sample. Also, field texturing was conducted at each site using the “feel” me thod described in Bra dy (1999). Values are reported at all locations with the exception of sites A4 and B4, where laboratory error gave invalid results. The following breakdow n of cells describes the soil textures as determined by the part icle-size distribution. For the purpose of study, soil analysis in the stormwater basin was separated into four areas: the northwest corn er of cell 1, the center and eastern portion of cell 1, all of cell 2, and all of cell 3. The major textural classes in the northwe stern portion of cell 1, sites A1 through A5, were determined to be sandy and loamy materials. Analysis indicated that 4 of the 5 surface samples in this location were classified as sands, with the remaining site, A3, texture a loamy sand. The subsurface samples ranged from sand to a loam texture. All of these site locations were in areas where no recent scrapping had occurred. In the remaining locations of cell 1, A6 through A12, surface textures varied from loamy sand to sandy clay loam. The sandier locations were repres ented by sites A6 and A9, which were not scraped during the re-c ontouring of the SEEP. Loamy sand extended into the 5-10cm depth at each of these locations. The rema ining sites within cell 1 had been scrapped down to the argillic horizon, leaving a sandy clay loam present at the surface, extending through the 5-10cm sample. The majority of sites sampled within cell 2 were of similar texture class as those identified in the center of cell 1. The surfaces for sites B1 through B4 had been removed

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69 during redesign of the basin, expos ing finer textured sandy clay loam material. Site B5 in the westerly region of this cell, howev er, had remained untouched, leaving sandy to loamy sand textured material. Cell 3 had been entirely reworked as part of the plan to enlarge and deepen the ponds to the south of the retention basin. Excavation in this ar ea completely removed any of the sandier textured soils down to the ar gillic horizon. Both sites evaluated in cell 3 fell within the textural tria ngle as either sandy clay loam or sandy clay. The control site soils were classified as sands in both the 0-5cm sample and the 5-10cm sample. Data for the particle-size distribution in the basin soils is listed in appendix C-1. Metals: Cadmium Cd vs. Baseline Concentration Levels Cd was detected at 5 of 19 soil sample locations within the stormwater retention basin. Concentrations in the 0-5cm samples ranged from 0-2.5 mg/kg and were identical in the 5-10cm sample depth. Detection above the upper limit of the baseline concentration range occurred in 4 of the 0-5cm samples and in 2 of the 5-10cm samples (Figure 18). Three of the sites where detecti on occurred were within the initial treatment zone, cell 1. The two remaining sites were split between cell 2 and cell 3. The sites where Cd was present were above the base line concentration range of 0-0.33 mg/kg as established for Florida surface soils (Chen et al., 1999). Cd was not detected in the control site sample located outside the retention basin. Cd Concentrations Compared With Various Screening Levels Of the 5 sites where Cd was detected, conc entrations at three locations, all in cell 1, were above the TEL of 0.676 mg/kg establis hed by the SQAGs (Figure 19). There

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70 were no exceedences for PELs of 4.20 mg/kg, or the SCTLs residential and commercial based values of 75 mg/kg and 1300 mg/kg respectively (Figure 20).

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0 0. 5 1 1. 5 2 2. 5 3A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsCadmi um Concent rat i on ( mg/ kg) 0-5cm 5-10cm 0-0.33 m g /k g Baseline Concentration Figure 18. Cadmium concentrations in the st ormwater basin soils. The baseline concentration range for cadmium in Florida surf ace soils is represented by the red shaded region..71

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72 A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A2 A1 B1 B2 B3 B4 C1 C2 D1Figure 19. Location of sites where cadmium concentrations were detected above threshold effects levels (TELs) derived by th e soil quality assessment guidelines. Sites above TELs are shaded in yellow. N 10m B5

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0 0. 5 1 1. 5 2 2. 5 3A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsCadmi um Concent rat i on ( mg/ kg) 0-5cm 5-10cm 0.676 mg/kg TEL Cell 1Cell 2Cell 3Figure 20. Comparison of cadmium concentrations to screening criteria throughout the entire basi n. These concentrations were evaluated at depths of 0-5cm and 5-10cm. Exceedences of screen ing criteria occurred for the th reshold effects level (TEL) deri ved by the soil quality assessment guidelines (SQAGs).73

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74 Metals: Chromium (Cr) Cr vs. Baseline Concentration Levels Cr was detected at all 19 sites within the stormwater retention basin with concentrations ranging from 21.0 -262.5 mg/ kg in the 0-5cm samples and from 12.0-180 mg/kg in the 5-10cm samples. When compared to baseline concentration data there were 4 sites that exceeded the established rang e of 0.89-80.7 mg/kg (Figure 21). These sites were located in cell 1, to the northwest co rner of the retention basin. The highest concentrations of Cr in these areas were de tected in the 0-5cm samples, with baseline exceedences in the 5-10cm samples occurring at only 2 of the 4 locations. When comparing elevations of Cr in the control sa mple, they fell within established baseline concentrations at both the 0-5cm sample (20.5 mg/kg), and the 5-10cm sample (23.5 mg/kg). Cr Concentrations Compared With Various Screening Levels Cr concentrations were compared to th e derived protection levels established under the SQAGs. Exceedences of TELs set at 52.3 mg/kg occurred at 4 sites within cell 1 to the northwest corner of the retention basin (Figure 22). Levels of concern extended into the 5-10cm depths at 2 of the locations Additionally, concentrations of Cr were high enough at these same 4 sites to ex ceed the PEL of 160 mg/kg, although, only one site showed a PEL exceedence at a 5-10cm depth. When comparing the data to the SCTL resi dential and commercial toxicity values, 2 sites contained Cr concentrations above the SCTL residential value of 210 mg/kg. The concentration of Cr above SCTLs did not exte nd to the 5-10 cm depth. There were no Cr concentrations above the SCTL commercial-b ased values of 420 mg/kg. Concentration

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75 of Cr in the 5-10cm samples exceeded leve ls in the 0-5cm samples at 6 of the 19 locations within th e basin (Figure 23).

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0 50 100 150 200 250 300A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsChromi um Concent rat i on ( mg/ kg) 0-5cm 5-10cm 0.89 80.7 mg/kg Baseline Concentration Range Figure 21. Chromium concentrations in the stormwater retention basin soils. The baseline conc entration range for chromium in Florida surface soils is represented by the red shaded region76

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Figure 22. Location of sites where chromium was detected above contaminant screening levels. (A) Sites exceeding threshold ef fects levels (TELs) as established by the soil quality assessment guidelines (SQAGs) are shad ed in yellow. (B) Sites exceeding pro bable effects levels (PELs) as esta blished by the SQAGs are shaded in red. (C) Si tes exceeding soil cleanup ta rget levels (SCTLs) established in Chapter 62-777, Florida Admini strative Code. Sites shaded in orange re present residential to xicity value excee dences (RTVs). A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5A A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5B A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5C N 20m 20m 20m N N77

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0 50 100 150 200 250 300A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsChromi um Concent rat i on ( mg/ kg) 0-5cm 5-10cm 52.3 mg/kg TEL 160 m g /k g PEL 210 m g /k g SCTL RTV Cell 1Cell 2Cell 3Figure 23. Comparison of chromium concentra tions to screening criteria throughout the entire basin. These concentrations were evaluated at depths of 0-5cm and 5-10cm. Exceedences of screen ing criteria occurred for the thre shold effects levels (TEL's) a nd probable effects levels (PELs) established by the soil quality assessment guidelines. Additionally, concentrations exceeded s oil cleanup target levels (SCTLs) for residentia l values (RTVs). Concentrations of ch romium in the 5-10cm depth samples exceeded the concentrations in the 0-5cm sample dept hs at 5 of the 19 sample site locations.78

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79 Metals: Copper (Cu) Cu Vs. Baseline Concentration Levels Cu concentrations were det ected at all 19 sites within the stormwater retention basin. Levels ranged from 5.5-235 mg/kg in the 0-5cm sample depths and from 3.0-102 mg/kg in the 5-10cm samples. Seven sites exceeded the upper limit of the baseline concentration range (Figure 24). Similar to both Cd and Cr, exceedences were observed in the northwest corner of cell 1. Elevated levels were also documented at three other locations within cell 1, includ ing the highest concentration at the northeastern stormwater inlet, and at one location in cell 3. In 18 of the 19 sites the 0-5cm sample depths contained a higher concentrati on of Cu, with the one exception being site A2. This was also the only location where the 5-10cm samp le depth exceeded the baseline range upper limit. Cu concentration in the control sample was at 3.0 mg/kg at both depths, which falls within the established baseline range. Cu Concentrations Compared With Various Screening Levels The SQAGs have a derived TEL for copper of 18.7 mg/kg. Cu concentrations in the soils of the retention basin exceeded TELs at 8 sites. Seven of these sites were located in cell 1, with the remaining site locat ed in cell 3. Two of the sites had levels of Cu in concentrations higher than the P EL of 108 mg/kg. Each of these two locations were in direct flow from the stormwater inle ts to the northwest a nd northeast areas of cell 1. The SCTLs have established exposure pr otection limits from Cu for residential and commercial applications of 110 mg/ kg, and 76,000 mg/kg, respectively. Residential exposure concentrations were exceeded at the tw o sites in direct flow from the inlets in

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80 cell1 (Figure 25). Cu was not detected at le vels exceeding the co mmercial based values established by the SCTLs. As indicated with the comparison to the baseline concentration range, concentrations of Cu in the 5-10cm depth samples tended to be lower than in the upper sample. Of the 7 sites where Cu was detected above screening levels exceedences in the 5-10cm sample depths occurred at only one site (Figure 26). This was consistent with the entire basin.

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0 50 100 150 200 250A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsCopper Concent rat i on ( mg/ kg) 0-5cm 5-10cm 0.22 21.9 mg/kg Baseline Concentration Range Figure 24. Copper concentrations in the stor mwater retention basin soils. The base line concentration range for copper in Flor ida surface soils is represented by the red shaded region81

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Figure 25. Location of sites where copper wa s detected above contaminant screening le vels. (A) Sites exceeding threshold effe cts levels (TELs) as established by the soil quality assessment guidelines (SQAGs) are shad ed in yellow. (B) Sites exceeding pro bable effects levels (PELs) as esta blished by the SQAGs are shaded in red. (C) Sites exceeding soil cleanup target levels (SCTLs) established in Chapter 62-777, Florida Admini strative Code. Sites shaded in orange re present residential to xicity value excee dences (RTVs). A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5A A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5B A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5C N 30m N 30m N 30m82

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0 50 100 150 200 250A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsCopper Concent rat i on ( mg/ kg) 0-5cm 5-10cm 18.7 mg/kg TEL 108 mg/kg PEL 110 mg/kg SCTL RV Cell 1Cell 2Cell 3Figure 26. Comparison of copper concentrations to screening criteria throughout the en tire basin. These concentrations were evaluated at depths of 0-5cm and 5-10cm. Exceedences of screen ing criteria occurred for the thre shold effects levels (TEL's) a nd probable effects levels (PELs) established by the soil quality assessment guidelines. Additionally, concentrations exceeded s oil cleanup target levels (SCTLs) fo r residential values (RTVs). Concentrations of c opper in the 5-10cm depth samples exceeded t he concentrations in the 0-5cm sample dept hs at only one site within the basin.83

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84 Metals: Lead (Pb) Pb Vs. Baseline Concentration Levels Concentrations of Pb were detected in soils at all 19 sites within the retention basin. Concentrations in the surface samples ranged from 7.0-61.0 mg/kg, and from 0.564.5 mg/kg in the 5-10cm depth samples. When compared the baseline concentrations, 2 sites exceeded the upper limits of the con centration range established at 0.69-42.0 mg/kg. Both locations were in cell 1 at the nor thwestern corner of the basin. Exceedences occurred in the upper samples at both locati ons and in the 5-10cm sample at one site (Figure 27). Pb concentrat ion in the control samples was at 4.5mg/kg and 5.0 mg/kg in the 0-5cm sample and the 5-10cm sample respectively. Pb Concentrations Compared With Various Screening Levels The concentrations of Pb in soils were co mpared to screening levels established in the SQAGs and the SCTLs. The SQAGs have derived a protection value of 30.2 mg/kg as a TEL for Pb in sediments. Basin soils ex ceeded this value at 4 locations, 3 of these sites being located in the northwestern corner of cell 1, and one site on the northern end of cell 3 (Figure 28). Exceedences occurred at the 0-5cm sample depth in 2 of the 3 locations in cell 1, and in the lone location in cell 3. Pb concentrations in the 5-10cm samples exceeded TELs at 2 locations in cell 1 only. When evaluating the entire basin, Pb concentrations in the 5-10cm samples exceeded the upper 0-5cm samples at 5 of 19 sites, or 26% (Figure 29). Pb did not exceed the PEL of 111.9 mg/kg or SCTLs for residential (400 mg/kg) and comm ercial (920 mg/kg) exposures.

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0 10 20 30 40 50 60 70A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsLead Concent rat i on ( mg/ kg) 0-5cm 5-10cm 0.69 42.0 mg/kg Baseline Concentration Range Figure 27. Lead concentrations in the stormw ater retention basin soils. The baseline concen tration range for lead in Florida s urface soils is represented by the red shaded region85

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86 Figure 28. Location of sites wh ere lead concentrations were detected above threshold effects levels (TEL’s) derived by the soil quality assessment guidelines. Sites above TEL’s are shaded in yellow. A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5 N 10m

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0 10 20 30 40 50 60 70A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsLead Concent rat i on ( mg/ kg) 0-5cm 5-10cm 30.2 mg/kg TEL Cell 1Cell 2Cell 3Figure 29. Comparison of lead concentrations to screening criteria thr oughout the entire basin. Thes e concentrations were eva luated at depths of 0-5cm and 5-10cm. Exceedences of screening criter ia occurred for the threshold effects level (TEL) derived by the soil quality assessment guidelines. Concentrations of lead in the 5-10cm depth samples exceed ed the concentrations in the 0-5cm sam ple depths at 5 of the 19 sites within the stormwater basin.87

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88 Metals: Nickel (Ni) Ni Vs. Baseline Concentration Levels Ni concentrations were detected at al l 19 sites located within the stormwater retention basin. Concentrati ons ranged from 5.5-29.0 mg/kg in the 0-5cm sample depths, and from 4.0-31.5 mg/kg in the 5-10cm sample s. When compared to the Ni baseline concentration range of 1.70-48.5 mg/kg there were no exceedences of the upper limits (Figure 30). In the control sample, the 05cm sample contained 2.5 mg/kg of Ni, and the 5-10cm sample contained a concentration of 3.0 mg/kg. Ni Concentrations Compared With Various Screening Levels When Ni concentrations in the retenti on basin were compared to the SQAGs, 2 sites had levels elevated above the TEL of 15.9 mg/kg. Both locations were in the northwest corner of cell 1, adjacent to the st ormwater inlets (Figur e 31). A third site in cell 1 had a Ni concentration of 15.0 mg/kg in the 0-5cm sample. Exceedences occurred in the 0-5cm samples at both locations, and in the 5-10cm sample at one site. There were no exceedences for the PEL of 15.8 mg/kg, or for the SCTL residential (110 mg/kg) and commercial (28,000 mg/kg) exposures at any of the sites. When evaluating Ni concentration throughout the en tire retention basin, levels decreased from the upper samples to the lower depths at 15 of the 19 sites (Figure 32).

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0 5 10 15 20 25 30 35A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsNi ckel Concent rat i on ( mg/ kg) 0-5cm 5-10cm 1.70 48.5 mg/kg Baseline Concentration Range Figure 30. Nickel concentrations in the st ormwater retention basin soils. The baseli ne concentration range for nickel in Flor ida surface soils is represented by the red shaded region89

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90 A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5Figure 31. Location of sites where nickel con centrations were dete cted above threshold effects levels (TEL’s) derived by the soil quality assessment guidelines. Sites above TEL’s are shaded in yellow. N 10m

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0 5 10 15 20 25 30 35A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsNi ckel Concent rat i on ( mg/ kg) 0-5cm 5-10cm 15.9 mg/kg TEL Cell 1Cell 2Cell 3Figure 32. Comparison of nickel concentrations to screening cr iteria throughout the entire basi n. These concentrations were evaluated at depths of 0-5cm and 5-10cm. Exceedences of screen ing criteria occurred for the th reshold effects level (TEL) deri ved by the soil quality assessment guidelines. Conc entrations of nickel in the 5-10cm depth samples exceeded the c oncentrations in th e 05cm sample depths at 2 of the 19 sites within the stormwater basin.91

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92 Metals: Zinc (Zn) Zn Vs. Baseline Concentration Levels Zn was detected at all 19 sites within the stormwater retention basin. Concentrations ranged from 10.5-720 mg/kg in the 0-5cm sample depths, and from 6.5558 mg/kg in the 5-10cm samples. When co mpared to the baselin e concentration range of 0.89-29.6 mg/kg, there were 10 sites that exce eded the upper limit of this range (Figure 33). The 0-5cm samples at these 10 locations were all above the baseline range, and 5 of these sites contained levels above the rang e into the 5-10cm sample depths. Seven of these locations were in cell 1, with the highest concentrations located in the northwestern corner. One site was in cell 2, and the other 2 were located in cell 3. Zn concentrations in the control sample were also above th e baseline concentration range at 32.5 mg/kg in the 0-5cm sample depth, and at 35.5 mg/kg in the 5-10cm sample. Zn Concentrations Compared With Various Screening Levels The SQAGs have established a TEL for Zn at 124 mg/kg. Concentrations within the stormwater retention basin exceeded this level at 3 locations in the northwestern corner of cell 1, adjacent to a major inflow. The levels, which were present at these locations, also exceeded the PEL for Zn of 271 mg/kg (Figure 34). Levels of Zn above SQAGs were present in the 0-5cm samples at all 3 locations, but extended into the lower samples at only one site. There were no concentrations above SCTLs for residential (23,000 mg/kg) or commercial (560,000 mg/kg) e xposures. When looking at all 19 sites within the retention basin, Zn concentrations decreased from the upper to the lower depth samples at 18 locations (Figure 35).

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Figure 33. Zinc concentrations in the stormwater retention basin soil. The base line concentration range for zinc in Florida su rface soils is represented by the red shaded region 0 100 200 300 400 500 600 700 800A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsZi nc Concent rat i on ( mg/ kg) 0-5cm 5-10cm 0.89 29.6 mg/kg Baseline Concentration Range93

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Figure 34. Location of sites where zinc was de tected above contaminant screening levels (A) Sites exceeding threshold effects levels (TELs) as established by the so il quality assessment guidelines (S QAGs) are shaded in yellow. (B) Sites exceeding probable e ffects levels (PELs) as established by the SQAGs are shaded in red. A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5A A12 A11 A10 A9 A8 A7A6 A5 A4 A3 A1 A2 B1 B2 B3 B4 C1 C2 D1 B5B N 20m N 20m94

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95 Figure 35. Comparison of zinc concentrations to screening criteria thr oughout the entire basin. These concentrations were eva luated at depths of 0-5cm and 5-10cm. Exceedences of screening criter ia occurred for the threshold effects level (TEL) derived by the soil quality assessment guidelines. Concentrations of lead in the 5-10cm depth samples exceed ed the concentrations in the 0-5cm sam ple depths at only one of the 19 sites within the stormwater basin. 0 100 200 300 400 500 600 700 800A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 C1 C2Si t e Locat i onsZi nc Concent rat i on ( mg/ kg) 0-5cm 5-10cm 124 m g /k g TEL 271 m g /k g PEL Cell 1Cell 2Cell 395

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96 Linear Regression Analysis Linear regression analyses were condu cted to determine correlations between metals and certain soil properties. All metals were regressed on pH, percent clay content, organic carbon, and organic matter. Variables with significant r2 values and corresponding p-values were identified and reported.

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97 DISCUSSION This research focused mainly on h eavy metal pollutant concentration identification and the possible threats these contaminants pose to both wildlife and human communities. The significance of contamination should be measured by its potential to impact upon an identified community. Through soil analysis, heavy metals were identified to be present within some soils in the stormwater basin at the NATL. Upon review of the results for this study, several points of discussion can be made regarding the current soil c onditions and the heavy meta l contaminant concentrations existing within the stormwater management system. With the exception of Cd, the remaining five metals analyzed were detected at all 19 sites within the stormwater management sy stem, and at the control site outside the basin. Metal concentrations within the basin exceeded typical background levels for Florida surface soils at 10 sample locations. The most common metal detected in excess of background levels was Zn, exceeding ba ckground levels at 10 sites, followed by Cu (7), Cd (5), Cr (4) and Pb (2). The only me tal not detected above what was considered to be baseline concentrations was Ni. Eight of the 10 sites where background ex ceedences occurred were at locations left undisturbed during the 1998 re-contouring of the basin. Sites A1 through A5 were the most prevelant in containing soils with background exceedences. There were two locations that had been scra ped in 1998, which did show concentrations of Zn, and Cu above background levels, sites A11 and C1. Both of these locati ons lay within eight

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98 meters of soils left in place from original basin construction. Sin ce they were not within a direct flow path adjacent to stormwater in flow pipes, contaminant concentrations may be attributed to either metal release from so ils in the older areas or from metal-organic matter complexes, allowing for smaller particulates to short circuit natural depositional pathways increasing their mobility. In addition to its prevalence within th e stormwater retention basin, Zn was detected above background levels in the contro l sample outside the stormwater collection area. The reason for this control sample exceedence may be stormwater runoff from behind the Performing Arts Center. Although runoff from this parking area is directed towards the stormwater inlet in cell 1, heavy rainfall events may allow sheet flow to discharge in the vicinity of the control sample site location. Other studies have suggested that Zn in rainfall may contribute directly to levels of Zn within stormwater basins, which may explain why no other stormwater related metals were exceeding background levels at the control site (Carr et al. 1995). Metals were detected at nine sites with in the basin at concentrations above TELs, as established by the SQAGs. The most common exceedence was Cu at 37%, followed by Pb and Cr at 21%. Cd, Ni, and Zn ranged from 16% to 11% respectively. Six of the nine locations where TEL exceedences occurred were undisturbed so ils that had been in place since original basin construction. Site s A2 through A5 in the northwestern corner on the retention basin contained the greate st number of TEL exceedences for each metal. Other locations included A6 at the northeastern inlet pipe, A12 adjacent to that point, the northern most point A9, and in two of the re-contoured areas A11 and C1. While TEL exceedences occurred mainly in the 0-5cm samp les, elevated concentration of metals in

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99 the 5-10cm samples were detected at the A2 and A5 locations. With A2 being located directly in the flow path of the main stormw ater inlet, and A5 being adjacent to this area the majority of the stormwater entering the ba sin would be directed to these locations. It was noted that the highest organic materials were present in the northwestern corner of cell 1, which correlated with soils previous ly not scraped and the greater number of TEL exceedences. PEL exceedences occurred at five sites within the stormwater retention basin. Metals detected above PELs were Cr, Cu and Zn, with four of the 5 sites being located in the northwestern corner of cell 1, and the remain ing site located at the stormwater inlet to the east of the same cell. All five locations were soils that had been previously left untouched during the 1998 construction. PEL c oncentrations extended into the 5-10cm samples for Cr and Zn at site A2, which ag ain corresponds to high organic concentrations within both sample depths, and is in dire ct flow from the major stormwater input. Cr and Cu were detected at concentr ations exceeding SCTLs for residential exposures as established in Chapter 62-777, F.A.C. Locations of exceedences were consistent with the TEL concentrations. From the data analyzed, the concentration of metals in the no rthwestern portion of cell 1 was not surprising. This area collects the greatest am ount of stormwater entering the system from the commuter lot and parki ng garage. The levels at which these metals were identified were of concern however, since this basin, at 12 years of age, is considered relatively young. In addition to the areas of concern fo r contaminant buildup, it was noted that during heavy rain events, stor mwater runoff entering the system from the southeastern

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100 portion of the SEEP was short-circuiting the treatment marsh. As sheet flows increased, runoff was able to discharge untreated di rectly to the infilt ration pond (Figure 36). Figure 36. Diagram of the SEEP with ar eas of concern and short-circuiting path highlighted. Area colored in red indicates region where contaminants were detected in soils not scraped during basin re-contou ring. Areas colored in green indicate contamination detected in soils that were scrapped during the recontouring of the basin. The blue arrow indicates stormwater inflow into the basin, short circuiting the treatment zones. N 10m

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101 The identification of elevated levels of metals in the soil, while significant, is only part of the contaminant equation. To comple te the cycle we must know the potential for a community to be negatively impacted. That potential comes from the concept of the NATL and the SEEP. As stated on its website, the NATL is a tract of land dedicated for use as a teaching facility by the University. Right now the major benefactors are the students at UF, but, the facility is open to the public. As indicated earlier, nine departments in four of the Colleges at UF either currently or pl an to use the NATL as part of their teaching curriculum. Data obtained from the NATL website estimates that approximately 2500 UF students will be receiving some type of c ourse work relating to the site. Several of the Departments have indicated the desire to use the facility for other projects outside the normal classroom studies, which will increase the number of individuals visiting the area (Natural Area Teaching Lab, http://natl.ifas.ufl.edu/natluses). In addition to the input of students fr om UF, the Florida Museum of Natural History gives guided tours of the NATL to K-12 students from Alachua and surrounding counties. The number of these types of visits is around 2400 stude nts per year, and is expected to grow as the area de velops (Natural Area Teaching Lab, http://natl.ifas.ufl.edu/natluse s). These numbers do not incl ude any visitations from the general public, not associated with the Univer sity of Florida. While estimates may reach over 5,000 people a year visiting the site, the actual number that could access the stormwater retention basin is unclear. The research and educational opportuniti es that the SEEP offers students and others are not the only planned benefits of th is area. In addition, the design of the basin is

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102 expected to be beneficial in creating plant diversity, a mo re diverse wildlife habitat, improved landscape appearance, and an overa ll increase in the overall quality of the stormwater exiting the system. Plantings were made throughout the basin intending to create species diversity, and let the natural processes of wetlands dictate the vegetative diversity (Wetlands Club, Undated) As the vegetative community has develope d, wildlife activity in the area has increased. During the course of this res earch many different species of the avian community were noticed, including several species of wading birds, which fed on organisms or other material in the soils of the basin. Anot her occupant of the stormwater basins northwestern corner was an alligator. She nested in the area where the majority of the elevated metal concen trations were detected. In an effort to create an aesthetic envi ronment (one of the desired outcomes of the SEEP) the basin was planted with a variety of species to mimic various wetland communities. The forebay, where the majority of the stormwater enters the basin, was planted with species known for their ability to take up meta ls and nutrients. Additional design considerations of the basin, includi ng the increased holding times of stormwater offered in the holding bay, were in place to improve the overall wa ter quality. Although bio-availability was not a ssessed in this study, vegeta tion selection and increased stormwater retention in combination with th e scrapping of soils during re-contouring may have been a reason that contamination wa s not seen distribute d throughout the entire basin. Another factor influencing metal distribu tion within the stormwater basin may be the leaching potential of the soils. As determined through soil analysis, the underlying

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103 horizons in the basin appear to be thick argillic horizons. These clays were additionally identified in previous soil logs throughout the basin. As organic matterstormwater contaminant complexes form, increased retention times may allow for further bonding between metals with the organic materials and clay minerals. While the concentrations of metal contam inants within the stormwater basin do warrant attention, their effects on both hum an and wildlife species may be limited. As previously detailed, there are no direct standa rds that apply to contaminant concentrations in soils of stormwater retention basins, nor an effective way to regulate any developable measures. Studies in Florida compare th eir findings to several regulatory program guidelines indirectly. Two common referen ces are the SCTLs outlined in Chapter 62777, Contaminant Cleanup Target Levels, and the threshold and probable effects levels described in SQAGs manual. The SCTL standards are developed for risk assessments based on factors such as individual body weight, exposure times, and exposure concentrations. One-time visitors or even researcher doing limited work in th e SEEP would be at low risk due to short exposure time. Another factor influencing ri sk is that the cont amination is basically limited to a small area within the basin. Identifying these areas may lead too a greater awareness, and precautionary steps can be ta ken to limit dermal and inhalation exposures. The wildcard could be the effects on the ve getative and wildlife communities of the stormwater basin. With smaller organisms th e effects may be magnified to a point where concentration, exposure time may be decr eased for adverse effects to occur. Use of the SQAGs for defining absolute contaminant issues are limited as well. These numbers were originally developed for coastal communities. The lack of good

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104 freshwater data has led researchers to appl y these standards indirectly to freshwater systems anyway. Guidelines for freshwater systems are currently being developed by the FDEP, but were not available during the course of this study. As stated in the manual, SQAGs are to be used with factors such as bio-availability studies when determining aquatic community risk evaluations. There is some evidence, though, that suggests soils with contaminant concentrations above PELs may pose a threat to the biotic communities existing within this system (FDEP, 2001). Se veral areas within the forebay, or cell 1, had exceedences of PEL’s. The vegetative cover a nd availability of wate r in these areas may make them prime locations for biological activity. The research completed detected various contaminants at varying concentrations within the stormwater basin. While the effect s of their presence within this system are not currently known, to ignore their existence could be a mistake. Indirectly applying regulatory standards for the purpose of envir onmental assessment studies may be the only tools available to profile these contaminant concentrations. Removal and remediation of soils may not always be the most effective measures when addressing this contamination. Instead, by identifying and deta iling contaminant locations, procedures can be put in place to effectively monitor and manage existing ecosystems. Simple Linear Regression Simple linear regression analyses were conducted on the six dependent metal variables to determine any significant correlation to certain soil characteristics. The independent soil characteristics used were pH, percent clay, organic carbon, and organic matter. Cd was not reported due to the limited number of detection sites available. Initial regressions were run using the entire set of 38 points. From that data set, r2values obtained were very low for metals regressed with pH, and percent clay content.

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105 Both Cr and Zn had moderately low r2 values of 0.36 and 0.24 respectively. Upon reviewing their associated regression curve it was noted that several outliers may have been influencing their relationships. Wh en these points were removed, the model lowered r2 in both cases. Organic carbon content in itially showed a moderate correlation to all metals. When analyzing the data se t, there were several points where organic carbon content was not determined, but instead assigned a limited value. The results if used may poorly reflect the relationships that exist. The strongest correlation for metal rela tionships was organic matter. Cr (r2 = 0.48), Ni (r2 = 0.27), Pb (r2 = 0.44), and Zn (r2 = 0.34), showed influence from organic matter content with n = 38. Rec ognizing that 2 separate popul ation may exist with th 0 – 5 cm samples and the 5 – 10 cm samples, regression r2 = 0.50s were run on both these data sets. In the surface samples, the r2 increased for Ni (r2 = 0.51), Pb (r2 = 0.50), and Zn (r2 = 0.47). Cr decreased slightly to a r2 of 0.46. Statistically, the 5 – 10 cm samples had r2 values below 0.5 with the exception of Cr (r2 = 0.56). Taking the regression one step further, the 0 – 5 cm samples were run for all locations within cell 1, sites A1 through A12. Reviewing the regression reports it was noticed that 2 locati ons within cell 1 may have been influenced by position within the cell. Using the linea r regression model it appeared both sites lay outside the normal proba bility plot. When these points, A2 and A5 were removed, the data set of n = 10 yielded strong r2 values of 0.91 for Ni, 0.93 for Pb, and 0.79 for Zn. These numbers by far were the strongest of any regression plot run, indicating organic matter content to be significantly correlated to the presence of Ni, Pb, and Zn. A complete table with all r2 and p-values can be found in Appendix C. Additional linear regressi on analysis curves are listed in Appendix D.

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106 Metal Loading Rates Since no regulations require frequent m onitoring of contaminant build-up over time within stormwater basin soils, it may be difficult to assess at what point these soils reach potentially toxic levels of metals. A method for estimation could be to take average concentrations of pollutants over time, comb ined with rainfall data to estimate total pollutant loads. This method would not account though for stormwater lost through infiltration, and could lead to over estima ting loading. The option chosen for this research was to use the L-THIA GIS-based model. Using the L-THIA model, estimated annual loading rates were esta blished for the SEEP basin. Before loading rates could be calculated, several steps were first taken. First, one of the prime components in generating runoff curve numbers in LTHIA is land use category. Since no land use GIS layer existed that was compatible for the L-THIA model, it had to be created. To do this, an aerial phot ograph of the area was obtained (Figure 36). By examining the phot ograph areas were designated as either open land, forested, or impervious surface for co mpatibility to L-THIA (Figure 37). Once these land use categories were in place, th e total water shed area was designated using United States Geological Survey quad maps (F igure 38). An existi ng soil type layer was added to the map (Figure 39). Using both the land use category, and soil classification layers, L-THIA generated the SCS curve number for the watershed based on one-meter cells. The next step was to apply annual rainfall data for the area based on 20-years of data. These estimates were obtained for Al achua County, and put into the model. LTHIA now generated estimated runoff from the watershed basin into the SEEP.

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Figure 37. GIS photograph of the area adjace nt to the stormwater retention basin107

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Figure 38. GIS land use classification designations for the areas surroundi ng the retention basin.108

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Figure 39. GIS designated la nd use classes within the retention basin watershed.109

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Figure 40. GIS soils layer adde d to land use classifications.110

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111 The final part of the equation was to co mpare metal concentrations in stormwater with the estimated runoff values generated by L-THIA. Since no site specific stormwater quality data was collected, the L-THIA de fault values, obtained from the TNRCC study were used (Table 6) Table 6. Metal concentrations in stor mwater runoff (Baird and Jennings, 1996) MetalCommercialTransitonMixedAgricultureRange g/L g/L g/L g/L g/L Pb1311121.55 Cu14.51113.91.510 Zn18060141166 Cd0.9611.0511 Cr1035.5107.5 Ni11.847.3N/AN/A Using metal concentrations in stormw ater runoff obtained by Baird and Jenning (1996), estimates of total annua l loading to the re tention basin were calculated. These annual rates were then compared to the calcul ated total mass of each metal existing in the upper 10 cm of soil in cell 1 of the basin, to determine the expected time frame needed to reach these specific levels (Table 7). Table 7. L-THIA generated loading rates co mpared to estimated total mass in SEEP. Estimated Age of Soil Surface (Yr) (total mass/loading rate) Cd90.0092.21.0 Cr20,628303.268.0 Cu10,482.00978.110.7 Ni2,916.00353.68.2 Pb9,177978.19.4 Zn30,096.005,364.65.6 Metal Total Mass in Upper 10 cm of Soil (kg) L-THIA Generated Loading Rates (kg/yr)

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112 When evaluating the results from L-THIA compared to actual metal concentrations, Cu, Ni and Pb, were the closes t concentrations in y ears of loading to the time frame of 11 years, which was the age of the basin when the sampling was conducted. Rates for Cd, Cr, and Zn, were le ss accurate. Factors affecting the out come of these results may come from not using site specific data, and the f act that the basin was assumed to have the same land use categories for the entire 11 year s, not reflecting any development in the area. In spite of the di fference in values obtai ned for the last three metals, the L-THIA model may be a valuable tool in determining pollutant build-up over time. Site specific data could play a major role in determining assessments for build-up, which could lead to regulations for site remediation.

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113 RECOMMENDATIONS From data collected, literature review ed, and field observations, the following recommendations are offered in regard s to continued operation of the SEEP. 1. A study to determine contaminant bio-availability should be completed at several sites within the SEEP. Meta l concentrations above TELs and PELs as established in the SQAGs were documented to exist at these locations. While SQAG values may indicate the potential for adve rse biological effects, they alone should not be used to establish sediment removal criteria. 2. Sediments should be removed from the three locations where contaminant concentrations were above residential toxi city values for the SCTLs, established in Chapter 62-777, F.A.C. These levels are based on exposure through dermal contact, ingestion or inhalation pote ntial. While the potential may be low for human safety factors, the risk to the wildlife communities in the area is unknown. 3. An assessment of the sediments for traffi c related petroleum hydrocarbons and PAH’s should be conducted. 4. Toxicity Characteristics Leaching Procedures (TCLP’s) should be performed in areas where the Soil Contaminant Cleanup Target Levels have been exceeded. This can assess the potential of the contaminants to spread throughout the basin, and will be useful in directing the method of sediment disposal upon removal.

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114 5. A study at the SEEP should be completed on the effects metal contamination may have on wildlife and vegetative communities. This study could directly impact the future direction in which the SEEP develops. 6. Monitoring should be continued for contam ination of sediments within the SEEP. Now that concentrations for metals have been established, peri odic checks, based on resource availability, should be completed by UF. This will generate data regarding the efficiency of the stormwater syst em on pollutant removal, and allow for potentially toxic or hazardous areas to be identified and addressed accordingly. 7. The SEEP area should be posted with signs indicating the pote ntial for exposure to possible contaminants contained in stormwat er, and that precautions should be taken when working within the basin. As focus on the disposal of urban stor mwater runoff continues to shift from quantity to quality based concerns, more research will be required to assess the functionality of wetland systems being used as contaminant filters. While studies have shown wetlands are capable of removing po llutants from stormwater runoff, higher quality of discharge does not always equate to increased environmental protection. We should not solely accept the benefits of ground and surface water protection through the use of stormwater management systems, w ithout recognizing the potential for localized sediment contamination. Stormwater manageme nt system evaluations similar to the one conducted on the SEEP have shown the potential for contamination in sediments to reach levels above toxicity guidelines established for soil cleanup sites, as well as exceedences of biological effects levels for aquatic organisms (FDEP, 2001).

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115 State, regional, and local governmental c odes have been established to regulate stormwater runoff relating to i ssues of flood control, on-site sediment containment, and quality of discharge to receiving waters Regulation on sediment quality within stormwater management systems is not ad equately addressed. Differing techniques of studies along with the variability of urban stormwater discha rge between sites has made it difficult to establish rules gove rning the pollutant potential of these sediments. Many times, guidelines such as the SCTLs or th e SQAG are indirectly applied to sediment studies for assessment purposes only. In the past, environmental protection from contaminated sediments was controlled through limiting access and decreasing desirability of stormwater management syst ems. However, as wetland systems become a more popular method of stormwater treatment and disposal, opportuniti es increase for the direct exposure of contamination from sedi ments to a variety of ecological communities, with the SEEP being no exception. The University of Florida has created a unique opportunity of environmental study with the development of the SEEP at the NATL. The design for this stormwater management system, with its multiple wetland communities, creates conditions conducive to attracting and sustaining a variet y of wildlife species. In addition, the University’s plan for using this site fo r continuing classroom study and research, along with the ease of accessibility by the public, bridge the barriers protecting humans and wildlife from exposure to possible contamin ated sediments. By addressing current contaminant areas, and monitoring for future concerns, the retent ion basin at the NATL may continue to be a vital research area, without the possessing th e potential to impact human and environmental health.

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APPENDIX A ACRONYM LIST OF AGENCIES AND PROGRAM AREAS

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117 Table A-1. Common acronyms used in this text. FDEPFlorida Department of Environmental Protection Texas Natural Resource Conservation Commission United States Environmental Protection A g enc y DCA EPA ERP FDOT NATL NOM NPDES Soil Quality Assessment Guideline Suwannee River Water Management District Southwest Florida Water Management District Threshold Effects Level Soil Conservation Service Soil Clean-up Target Level Stormwater Ecological Enhancement Program St. Johns River Water Management District National Pollutant Discharge Elimination System Non-Point Source Management Program Nationwide Urban Runoff Program Probable Effects Level TNRCC USEPA Department of Co mmunity Affairs Department of Environmental Regulation Environmental Protection Agency Environmental Resource Permit Florida Department of Transportation Natural Area Teaching Lab Natural Organic Matter SQAG SRWMD SWFWMD TEL SCS SCTL SEEP SJRWMD NPSMP NURP PEL DER ATSDR Acronym ACEPDAlachua County Environmental Protection Department Title Agency for Toxic Substan ces and Disease Registry

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APPENDIX B ADDITIONAL FIGURES

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119 Existing Pond Proposed Stormwater Basin 1988 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14Figure B-1. 1988 proposed retention ba sin with soil boring locations.

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Figure B-2. Soil boring locations 1 – 4. Borings conducted in 1988 by Bishop Bevi lle for the University of Florida.120

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Figure B-3. Soil boring locations 5 – 8. Borings conducted in 1988 by Bishop Bevi lle for the University of Florida.121

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Figure B-4. Soil boring locations 9 – 12. Borings conducted in 1988 by Bishop Bevi lle for the University of Florida.122

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Figure B-5. Soil boring location 13. Borings conducted in 1988 by Bishop Bevill e for the University of Florida.123

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APPENDIX C ANALYTICAL RESULTS

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125 Table C-1. Particle-size analysis for cell 1 Site Depth% Sand% Silt% ClayTextural Class A1 0-5cm89.247.403.36Sand A1 5-10cm93.564.841.60Sand A2 0-5cm96.242.641.12Sand A2 5-10cm92.362.365.28Sand A3 0-5cm82.304.5813.12Loamy Sand A3 5-10cm82.695.3112.00Loamy Sand A4 0-5cm96.581.981.44Sand A4 5-10cmLABERRORN/AN/A A5 0-5cm89.744.825.44Sand A5 5-10cm37.2347.2515.52Loam A6 0-5cm87.803.248.96Loamy Sand A6 5-10cm95.282.482.24Sand A7 0-5cm73.784.9421.28Sandy Clay Loam A7 5-10cm74.544.3421.12Sandy Clay Loam A8 0-5cm67.885.7226.40Sandy Clay Loam A8 5-10cm65.164.6030.24Sandy Clay Loam A9 0-5cm85.624.949.44Loamy Sand A9 5-10cm83.495.7910.72Loamy Sand A10 0-5cm64.298.0327.68Sandy Clay Loam A10 5-10cm64.565.2030.24Sandy Clay Loam A11 0-5cm64.908.8626.24Sandy Clay Loam A11 5-10cm65.287.6827.04Sandy Clay Loam A12 0-5cm55.4511.7532.80Sandy Clay Loam A12 5-10cm62.163.7634.08Sandy Clay Loam

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126 Table C-2. Particle-size analysis for cell 2 Site Depth% Sand% Silt% ClayTextural Class B1 0-5cm65.225.3429.44Sandy Clay Loam B1 5-10cm70.763.9625.28Sandy Clay Loam B2 0-5cm67.677.3724.96Sandy Clay Loam B2 5-10cm67.574.4328.00Sandy Clay Loam B3 0-5cm67.407.9624.64Sandy Clay Loam B3 5-10cm69.076.2924.64Sandy Clay Loam B4 0-5cm58.486.1635.36Sandy Clay Loam B4 5-10cm61.967.6430.40Sandy Clay Loam B5 0-5cm52.2214.6633.12Sandy Clay Loam B5 5-10cm71.499.9518.56Sandy Loam Table C-3. Particle-size analysis for cell 3 and control site Site Depth% Sand% Silt% ClayTextural Class C1 0-5cm39.7215.6444.64Clay C1 5-10cm41.4513.4345.12Clay Loam C2 0-5cm68.705.8625.44Sandy Clay Loam C2 5-10cm84.768.047.20Loamy Sand D1 0-5cm96.581.981.44Sand D1 5-10cm89.226.624.16Sand

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127 Table C-4. Laboratory analysis for per cent organic carbon (%OC), percent organic matter (%OM), and pH. Site LocationDepth%OC%OM pH (H20) pH (KCl) A10-5cm1.523.707.6 7. 1 5-10cm0.962.707.6 7. 5 A20-5cm7.0013.627.9 7. 8 5-10cm7.0010.008.1 7. 7 A30-5cm7.0014.627.8 7. 1 5-10cm0.993.008.1 7. 5 A40-5cm2.332.708.3 7. 8 5-10cm1.111.708.3 7. 9 A50-5cm7.0022.008.3 7. 8 5-10cm7.0021.007.6 7. 4 A60-5cm4.117.006.2 4. 7 5-10cm0.365.005.9 4. 7 A70-5cm0.644.306.8 6. 6 5-10cm0.183.706.8 5. 9 A80-5cm2.104.006.5 5. 4 5-10cm0.115.005.8 4. 2 A90-5cm0.582.005.9 4. 5 5-10cm0.232.005.5 4. 3 A100-5cm3.486.707.2 6. 6 5-10cm0.145.305.5 4. 3 A110-5cm4.195.306.4 5. 4 5-10cm0.475.305.7 4. 5 A120-5cm0.852.005.9 4. 5 5-10cm0.371.006.2 4. 9 B10-5cm0.385.305.4 4. 2 5-10cm0.114.305.1 3. 9 B20-5cm0.274.007.1 5. 8 5-10cm0.214.707.0 5. 7 B30-5cm0.234.306.7 6. 0 5-10cm0.113.705.5 4. 0 B40-5cm0.235.005.8 4. 7 5-10cm0.115.005.6 4. 4 B50-5cm0.248.605.1 4. 6 5-10cm0.184.305.1 4. 2

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128 Table C-4. Continued Site LocationDepth%OC%OM pH (H20) pH (KCl) C10-5cm1.7211.007.0 5. 8 5-10cm0.547.006.8 5. 6 C20-5cm0.638.006.7 5. 3 5-10cm0.128.305.3 4. 0 D10-5cm0.783.606.1 5. 5 5-10cm0.752.606.2 5. 6

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129 Table C-5. Metal Concentrations Site LocationDepthCdCrZnCuNiPb (mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg) A10-5cm045.54116.55.57 5-10cm020221343 A20-5cm2.5262.572099.52961 5-10cm2.518055810231.564.5 A30-5cm1.52504441481942.5 5-10cm04039911.518.5 A40-5cm016041.512.5611 5-10cm020.530.5125.513.5 A50-5cm1177.5276.5611524.5 5-10cm013994.5186.532.5 A60-5cm044.54123511.523.5 5-10cm035.513610.521.5 A70-5cm02117.515814 5-10cm0239.547.514.5 A80-5cm0291310.51016.5 5-10cm012223.543.5 A90-5cm027.518.545.578.5 5-10cm013123.54.52.5 A100-5cm039.5145.59.516 5-10cm029.512.537.516.5 A110-5cm03836.522.510.519 5-10cm03214.549.518.5 A120-5cm03810.51967 5-10cm041.56.553.50.5 B10-5cm025.515.511.5817.5 5-10cm02495.5713.5 B20-5cm024.5177.5714 5-10cm0301167.513.5 B30-5cm027165.57.514 5-10cm0271247.512.5 B40-5cm022.520.5157.514 5-10cm022.51815813 B50-5cm0.544.55715.511.526.5 5-10cm02128.59.55.511.5 C10-5cm038.540411031.5 5-10cm047.535161021.5 C20-5cm0323516.58.526 5-10cm0.538.520.56818.5 D10-5cm020.532.532.54.5 5-10cm023.535.5335

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130 Table C-6. Metal concentrations co mpared to regulatory guidelines. Metal (Cd) SiteConcentrationTELPELResidentialCommercial (mg/kg)(0.676 mg/kg)(4.21 mg/kg)(75 mg/kg)(1300 mg/kg) A2 0 5 cm2.5YesNoNoNo A2 5 10 cm2.5YesNoNoNo A3 0 5 cm1.5YesNoNoNo A5 0 5 cm1YesNoNoNo SQAGsSCTLs Metal (Cr) SiteConcentrationTELPELResidentialCommercial (mg/kg)(52.3 mg/kg)(160 mg/kg)(210 mg/kg)(420 mg/kg) A2 0 5 cm262.5YesYesYesNo A2 5 10 cm180YesYesNoNo A3 0 5 cm250YesYesYesNo A4 0 5 cm160YesYesNoNo A5 0 5 cm177.5YesYesNoNo A5 5 10 cm139YesNoNoNo S Q AGsSCTL Metal (Cu) SiteConcentrationTELPELResidentialCommercial (mg/kg)(18.7 mg/kg)(108 mg/kg)(110 mg/kg)76,000 mg/kg) A2 0 5 cm 99. 5 YesNoNoNo A2 5 10 cm 102 YesNoNoNo A3 0 5 cm 148 YesYesYesNo A5 0 5 cm 61 YesNoNoNo A6 0 5 cm 235 YesYesYesNo A9 0 5 cm45. 5 YesNoNoNo A11 0 5 cm22. 5 YesNoNoNo A12 0 5 cm19 YesNoNoNo C1 0 5 cm41 YesNoNoNo SQAGsSCTL

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131 Table C-6 (cont.) Metal (Zn) SiteConcentrationTELPELResidentialCommercial (mg/kg)(124 mg/kg)(271 mg/kg)(23,000 mg/kg)(560,000 mg/kg) A2 0 5 cm720YesYesNoNo A2 5 10 cm558YesYesNoNo A3 0 5 cm444YesYesNoNo A5 0 5 cm276.5YesYesNoNo SQAGsSCTLs Metal (Pb) SiteConcentrationTELPELResidentialCommercial (mg/kg)(30.2 mg/kg)(112 mg/kg)(400 mg/kg)(920 mg/kg) A2 0 5 cm61YesNoNoNo A2 5 10 cm64.5YesNoNoNo A3 0 5 cm42.5YesNoNoNo A5 5 10 cm32.5YesNoNoNo C1 0 5 cm31.5YesNoNoNo SQAGsSCTLs Metal (Ni) SiteConcentrationTELPELResidentialCommercial (mg/kg)(15.9 mg/kg)(42.8 mg/kg)(110 mg/kg)(28,000 mg/kg) A2 0 5 cm29YesNoNoNo A2 5 10 cm31.5YesNoNoNo A3 0 5 cm19YesNoNoNo SQAGsSCTLs

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132 Table C-7. Regression anal ysis on all sites, n = 38. All Samples 0-10cmOutliers Removed Regression r2p-value r2p-value Cd vs. OM0.28420.00060.49570 Cr vs. OM0.48400.26710.0018 Cu vs. OM0.1620.01230.21190.0062 Ni vs. OM0.27180.00080.59750 Pb vs. OM0.444100.77720 Zn vs. OM0.33770.00010.44260 Cd vs. OC0.501700.32080.0005 Cr vs. OC0.737300.51970 Cu vs. OC0.40800.47160 Ni vs. OC0.512300.43710 Pb vs. OC0.542800.28380.0012 Zn vs. OC0.608900.52250 Cd vs. % Clay0.16740.01190.02220.4078 Cr vs. % Clay0.21970.00340.06780.1432 Cu vs. % Clay0.11640.03880.04930.2143 Ni vs. % Clay0.10060.05580.00110.8539 Pb vs. % Clay0.05090.17930.02280.4014 Zn vs. % Clay0.17550.00990.02310.3982 Cd vs. [H+] (in H20)0.01370.48340.01120.5521 Cr vs. [H+] (in H20) 0.08640.07330.04270.2411 Cu vs. [H+] (in H20) 0.06620.11890.04310.2385 Ni vs. [H+] (in H20) 0.04470.20280.01770.453 Pb vs. [H+] (in H20) 0.03680.24840.0040.7216 Zn vs. [H+] (in H20) 0.04780.18720.01430.5008 Cd vs. [H+] (in KCl)0.03080.291700.9798 Cr vs. [H+] (in KCl)0.10970.04220.06020.1619 Cu vs. [H+] (in KCl)0.0920.06410.06450.1472 Ni vs. [H+] (in KCl)0.06780.11440.04580.224 Pb vs. [H+] (in KCl)0.07280.10150.03160.3147 Zn vs. [H+] (in KCl)0.06890.11140.03650.279

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133 Table C-8. Regression analysis on all sites 0 – 5 cm, n = 19All Samples 0-5cmOutliers Removed Regression r2p-value r2p-value Cd vs. OM0.49430.00080.54140.0008 Cr vs. OM0.45690.00150.26750.0335 Cu vs. OM0.1680.08140.21090.0636 Ni vs. OM0.5080.00060.8290 Pb vs. OM0.49680.00080.94090 Zn vs. OM0.47010.00120.53730.0008 Cd vs. OC0.56820.00020.37520.009 Cr vs. OC0.68580.50080.0015 Cu vs. OC0.37140.00560.40870.0057 Ni vs. OC0.635300.5830.0004 Pb vs. OC0.45160.00160.31560.0189 Zn vs. OC0.6180.00010.51890.0011 Cd vs. % Clay0.20310.0528 0.01750.6126 Cr vs. % Clay0.37520.0053 0.19670.0746 Cu vs. % Clay0.17950.0706 0.1330.1501 Ni vs. % Clay0.12860.1316 0.00160.88 Pb vs. % Clay0.0320.4637 0.04960.3903 Zn vs. % Clay0.24380.0317 0.05490.3656 Cd vs. [H+] (in H20)0.00280.82950.0230.5613 Cr vs. [H+] (in H20) 0.05380.33910.0270.5285 Cu vs. [H+] (in H20) 0.05020.35660.03770.4554 Ni vs. [H+] (in H20) 0.00270.83250.01970.591 Pb vs. [H+] (in H20) 00.98320.02610.5359 Zn vs. [H+] (in H20) 0.03030.47620.00730.7444 Cd vs. [H+] (in KCl)0.05430.33720.01280.665 Cr vs. [H+] (in KCl)0.1180.14990.07370.2919 Cu vs. [H+] (in KCl)0.09860.19060.07740.2795 Ni vs. [H+] (in KCl)0.03180.46530.00040.9386 Pb vs. [H+] (in KCl)0.02820.49190.00270.8424 Zn vs. [H+] (in KCl)0.07550.25490.04060.438

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134 Table C-9. Regression analysis on all samples, 5 – 10 cm, n = 19All Samples 5-10cmOutliers Removed Regression r2p-value r2p-value Cd vs. OM0.08050.23910.32060.0178 Cr vs. OM0.55830.00020.11630.1804 Cu vs. OM0.1230.14090.00480.7906 Ni vs. OM0.40160.2280.25990.0366 Pb vs. OM0.37410.00540.4060.0059 Zn vs. OM0.1430.11040.01780.6099 Cd vs. OC0.42490.00250.03660.4619 Cr vs. OC0.915600.02620.5348 Cu vs. OC0.5730.00020.25520.0386 Ni vs. OC0.3810.00490.00750.7408 Pb vs. OC0.641900.00170.8759 Zn vs. OC0.60550.00010.38070.0083 Cd vs. % Clay0.13280.13710.10170.2288 Cr vs. % Clay0.07290.27840.0470.42 Cu vs. % Clay0.09140.22280.0110.011 Ni vs. % Clay0.08330.245400.9857 Pb vs. % Clay0.08030.25450.00150.8884 Zn vs. % Clay0.10760.18390.0010.9079 Cd vs. [H+] (in H20)0.01850.57850.07360.2923 Cr vs. [H+] (in H20) 0.11450.15640.10370.2076 Cu vs. [H+] (in H20) 0.06220.30320.04640.4064 Ni vs. [H+] (in H20) 0.0720.26660.06840.3107 Pb vs. [H+] (in H20) 0.07970.24160.01640.6247 Zn vs. [H+] (in H20) 0.05320.34210.02390.5536 Cd vs. [H+] (in KCl)0.01710.59410.15120.123 Cr vs. [H+] (in KCl)0.12240.1420.06920.3078 Cu vs. [H+] (in KCl)0.08850.21620.15740.1239 Ni vs. [H+] (in KCl)0.06180.30490.02740.5259 Pb vs. [H+] (in KCl)0.07680.25060.00490.7901 Zn vs. [H+] (in KCl)0.06970.27470.12870.1574

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135 Table C-10. Regression analysis on cell 1, 0 – 5 cm, n = 12All Samples 0-5cm Cell 1Outliers Removed Regression r2p-value r2p-value Cd vs. OM0.54310.00630.78060.0007 Cr vs. OM0.52940.00730.47920.0265 Cu vs. OM0.16070.19650.350.0716 Ni vs. OM0.51940.00820.90560 Pb vs. OM0.45730.01580.92770 Zn vs. OM0.51650.00850.79120.0006 Cd vs. OC0.63810.00180.55510.0134 Cr vs. OC0.64860.00160.46430.03 Cu vs. OC0.27730.07860.34380.0748 Ni vs. OC0.7060.00060.8020.0005 Pb vs. OC0.69570.00070.83720.0002 Zn vs. OC0.63990.00180.59570.0089 Cd vs. % Clay0.19670.14870.01550.732 Cr vs. % Clay0.32770.05180.15450.2612 Cu vs. % Clay0.13290.24390.10870.3522 Ni vs. % Clay0.11760.27520.00460.8518 Pb vs. % Clay0.12210.26550.00050.9496 Zn vs. % Clay0.22090.12320.03790.59 Cd vs. [H+] (in H20)0.15490.20560.08150.4238 Cr vs. [H+] (in H20) 0.26270.08840.18240.2184 Cu vs. [H+] (in H20) 0.13490.24030.11760.332 Ni vs. [H+] (in H20) 0.05540.46150.00020.9722 Pb vs. [H+] (in H20) 0.06220.43450.00440.856 Zn vs. [H+] (in H20) 0.16260.19360.0990.3758 Cd vs. [H+] (in KCl)0.11340.28450.05810.5025 Cr vs. [H+] (in KCl)0.19060.15590.12770.3107 Cu vs. [H+] (in KCl)0.14450.22290.12850.3092 Ni vs. [H+] (in KCl)0.04710.49810.00040.9554 Pb vs. [H+] (in KCl)0.05590.45920.00920.7923 Zn vs. [H+] (in KCl)0.12040.26920.07230.4525

PAGE 149

APPENDIX D REGRESSION ANALYSIS

PAGE 150

Figure D-1. Regression curve for Cr, Ni Pb and Zn; all points are observed. 0.0 75.0 150.0 225.0 300.0 0.06.312.518.825.0Cr vs X_OMX_OMCr -200.0 50.0 300.0 550.0 800.0 0.06.312.518.825.0Zn vs X_OMX_OMZn 0.0 8.8 17.5 26.3 35.0 0.06.312.518.825.0Ni vs X_OMX_OMNi 0.0 20.0 40.0 60.0 80.0 0.06.312.518.825.0Pb vs X_OMX_OMPb r r2 2 = = 0 0 . 4 4 4 4 r r2 2 = = 0 0 . 2 2 7 7 r r2 2 = = 0 0 . 3 3 4 4 r r2 2 = = 0 0 . 4 4 8 8 A A l l l l D D a a t t a a P P o o i i n n t t s s 137

PAGE 151

Figure D-2. Regression curve for Cr, Ni, Pb and Zn, with outliers removed 0.0 62.5 125.0 187.5 250.0 0.04.08.012.016.0Cr vs X_OMX_OMCr -100.0 50.0 200.0 350.0 500.0 0.04.08.012.016.0Zn vs X_OMX_OMZn 0.0 5.0 10.0 15.0 20.0 0.04.08.012.016.0Ni vs X_OMX_OMNi 0.0 12.5 25.0 37.5 50.0 0.04.08.012.016.0Pb vs X_OMX_OMPb r r 2 2 = = 0 0 . 7 7 8 8 r r 2 2 = = 0 0 . 6 6 0 0 r r 2 2 0 0 . 4 4 4 4 r r 2 2 = = 0 0 . 2 2 6 6 O O u u t t l l i i e e r r s s R R e e m m o o v v e e d d 138

PAGE 152

Figure D-3. Regression analysis for Pb and Ni in the t op 5 cm of soil for every site throughout the entire basin. 5.0 15.0 25.0 35.0 45.0 2.05.59.012.516.0Pb vs X_OMX_OMPb 4.0 8.0 12.0 16.0 20.0 2.05.59.012.516.0Ni vs X_OMX_OMNi r r2 2 = = 0 0 . 9 9 4 4 r r2 2 = = 0 0 . 7 7 6 6 E E n n t t i i r r e e B B a a s s i i n n : : 0 0 5 5 c c m m 139

PAGE 153

Figure D-4. Regression analysis for Pb and Ni in top 5 cm of soil for sites located in cell 1. 5.0 15.0 25.0 35.0 45.0 2.05.59.012.516.0Pb vs X_OMX_OMPb 4.0 8.0 12.0 16.0 20.0 2.05.59.012.516.0Ni vs X_OMX_OMNi r r2 2 = = 0 0 . 9 9 4 4 r r2 2 = = 0 0 . 7 7 6 6 E E n n t t i i r r e e B B a a s s i i n n : : 0 0 5 5 c c m m 140

PAGE 154

141 REFERENCES Agency for Toxic Substances and Disease Registry. Toxprofiles, update s information on hazardous substances. 2001. ATSDR, Atlanta, Georgia. Accessed 6/10/02. www.atsdr.cdc.gov /. Agvise Laboratories, Soil Organic Matter: A Choice of Methods. 2001. Accessed 6/6/02. www.agviselabs.com/. Alachua, County of, Title 34, Chapter 343, Stormwater Management 1992. County Ordinance, Gainesville, Florida. Accessed 6/15/02. http://livepublish.municode.com Alachua, County of, Title 4, Chapter 44, Stormwater Management Utility 1996. County Ordinance, Gainesville, Florida. Accessed 6/15/02. http://livepublish.municode.com Athayde, D.N., Shelley, P.E., Driscoll, E.D., Gaboury, D., & Boyd, G. “Results of the National Urban Runoff Program (NURP).” Executive Summary 1983. U.S. Environmental Protection Agency, Washington D.C. Beville, Bishop. 1988. Soil Boring Analysis at UF Basin #8. Bishop Beville & Associates, Inc, Gainesville, Florida. Broadbent, F.E. “Organic Matter.” In C.A. Black (ed). Methods of Soil Analysis, Part 2 Agronomy 9. 1965. pp. 1397-1400. Am. Soc. Of Agron., Inc. Madison, Wisconsin. Carleton, J.N., Grizzard, T.J., Godrej, A.N ., & Post, H.E. “Factors Affecting The Performance of Stormwater Treatment Wetlands.” Journal of Water Resources Vol. 35, No. 6. 2001. pp 1552-1562, 2001. Carr, D.W. and Rushton, B.T. “Integrating A Native Herbaceous Wetland Into Stormwater Management.” 1995. Southwest Florida Water Management District, 2379 Broad St., Brookesville, Florida.

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142 Chen, M., Ma, L.Q., and Harris, W.G. “Baseline Concentrations of 15 Elements In Florida Surface Soils.” Journal of Environmental Quality Vol. 28. 1999. pp. 1173-1181. Cheng, S.P., Grosse, W., Karrenbrock, F., and Thoennessen, M. “Efficiency of constructed wetlands in decontamina tion of water polluted by heavy metals.” Ecological Engineering vol. 18. 2002. pp. 317-325. Cox, J.H., Allick, S., and Be, E. “Charact erization of Stormwater Contaminated Sediment and Debris for Determining Pr oper Disposal Methods.” 1998. Florida Department of Environmental Protect ion, Division of Water Facilities, 2600 Blairstone Road. Tallahassee, Florida. Day, P.R. “Particle Fractionation and Particle Size Analysis.” In: C.A. Black (ed). Methods of Soil Analysis, Part I Agronomy 9. 1965. pp. 545-567. Fischer, D., Charles, E.G., Baehr, A.L. “E ffects of Stormwater Infiltration on Quality of Groundwater Beneath Retention and Detention Basins.” Journal of Environmental Engineering Vol. 129, No. 5. 2003. pp. 464-471. Florida Department of Environmental Protection. Model Local Government Stormwater Management Program Stormwater/Nonpoint Source Management Section, FDEP, 1993. 2600 Blairstone Road. Tallahassee, Florida. Florida Department of Environmental Protection. Non-Point Source Management, Urban Stormwater Program FDEP. 2001. Accessed 6/16/02. http://www.dep.state.fl.us/water/nonpoint/urban1.htm Florida Department of Environmental Protection. Chapter 62-25 F.A.C., Regulation of Stormwater Discharge 1995. FDEP. Tallhassee, Florida. Florida Department of Environmental Protection Chapter 62-777 F.A.C., Contaminant Cleanup Target Levels 1999. FDEP. Tallhassee, Florida. Florida Department of Environmental Protection. Soil Quality Assessment Guidelines for Coastal Sediments 2000. Technical Document. FDEP. Tallhassee, Florida. Gainesville, City of, Chapter 30, Section 30-270, Stormw ater Management Generally; Erosion and Sedimentation Control; Design and Maintenance of Facilities City Ordinance. 1992. Gainesville, Florida. Accessed 6/15/02. http://livepublish.municode.com Gainesville, City of, Chapter 27, Article V, Secti on 27-238, Stormwater Management Utility, Established City Ordinance. 1998. Gainesville, Florida. Accessed 6/15/02. http://livepublish.municode.com

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143 Goulet, R.R. and Pick, F.R. “The effects of cattails (Typha latifolia L.) on concentrations and partitioning of metals in surficia l sediments of surface-flow constructed wetlands.” Water Air and Soil Pollution Vol. 132. 2001. pp. 275-291. Igloria, R.V., Hathhorn, W.E., Member, ASCE, and Yonge, D.R. “NOM And Trace metal Attenuation During Stormwater Infitration.” Journal of Hydrologic Engineering Vol. 2, No. 3. July 1997. ASCE, ISSN. Kao, C.M., Wang, J.Y., Lee, H.Y. and Wen, C. K. “Application of a constructed wetland for non-point source pollution control.” Water Science and Technology Vol. 44 (11 – 12). 2001. pp. 585-590. Keller, C. and Vedy, J.C. “Distribution of Copper And Cadmium Fractions In Two Forest Soils ” Journal of Environmental Quality Vol. 23. 1994. pp. 987-999. Lawrence, A.L., Marsalek, J., Ellis J.B., and Urbonas, B. “Stormwater detention & BMPs.” Journal of Hydraulic Research Vol. 34, No. 6. 1996. pp. 799-813. Livingston, E.H. and J.H. Cox. “Stormwater Sediments: Hazardous Waste or Dirty Dirt?” Proceedings of the 4th Biennial Stormwater Research Conference 1995. Published by Southwest Florida Water Management District, Brooksville, Florida. Livingston, E.H. and McCarron, E. Stormwater Management: A Guide for Floridians 1991. Florida Department of Environmental Regulation, Stormwater/Nonpoint Source Management, 2600 Blairstone Road. Tallahassee, Florida. Mikkelsen, P.S., Hafliger, M., Ochs, M., J acobsen, P., Tjell, J.C., and Boller, M. “Pollution of Soil And Groundwater From Infiltration of Highly Contaminated Stormwater – A Case Study.” Journal of Water Science Technology Vol. 36. 1997. pp.325-330. Rushton, B.T. and Dye, C.W. An In-Depth Analysis Of A Wet Detention Stormwater System 1993. Southwest Florida Water Management District, 2379 Broad St. Brooksville, Florida. Southwest Florida Water Management District. Comprehensive Quality Assurance Plan 1993. Southwest Florida Water Management District, 1379 Broad St. Brooksville, Florida. St. John River Water Management District. Chapter 40C-4, Environmental Resource Permits: Surface Wate r Management Systems 1995. SJRWMD, Palatka, Florida.

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144 Still, David. Suwannee River Water Manage ment District. Telephone Interview. 14 Sept. 2000. Thomas, B.P., Cummings, E. and Wittstruck, W.H. Soil Survey of Alachua County 1985. Soil Conservation Service, United States Department of Agriculture. University of Florida. Undated. Natural Area Teaching Laboratory Accessed 5/1/03. http://natl.ifas.ufl.edu/natluses) Walker, D.J., and Hurl, S. “The reduction of heavy metals in a stormwater wetland.” Ecological Engineering VOL.18. 2001. pp. 407-414. Walkley, A. and Black, I.A. 1934. “Chemical An alysis: Organic Carbon”. Soil Survey Laboratory Methods Manual, 1996. Report No. 42, Version 3.0, pg. 222. United Stated Department of Agriculture. Wetlands Club, University of Florida. Unda ted. Stormwater Ecological Enhancement Project. Handout Brochure. Gainesville, Florida.

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145 BIOGRAPHICAL SKETCH Mark Stanton Lander was born April 2, 1965, in Naples, Florida. He graduated from Naples High School in 1983 and entered Edison Community College in Fort Myers, Florida. Upon completion of community college requirements, Mr. Lander entered the University of Florida, College of Agricu lture, and was awarded a bachelor’s degree in food and resource economics in 1989. After graduation, he became employed by the Florida Department of Health conducting studi es in sewage dispos al practices along the Suwannee River, in North Florida. In 1994, Mr. Lander accepted a position with the Alachua County Health Department as an Environmental Specialist and was later promoted to water/waster supervisor. In 1998, Mr. Lander re-entered the Universi ty of Florida to pursue a Master of Science degree with specializa tion in urban soils. In September of 2003, he accepted a position at the Columbia County Health Depa rtment, as Director of Environmental Health. After graduation, Mr. Lander will co ntinue his work in the environmental health field.


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Material Information

Title: Evaluation of Selected Heavy Metal Concentrations in Soils of an Urban Stormwater Retention Basin
Physical Description: Mixed Material
Copyright Date: 2008

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Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
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EVALUATION OF SELECTED HEAVY METAL CONCENTRATIONS
IN SOILS OF AN URBAN STORMWATER RETENTION BASIN


















By

MARK S. LANDER


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2003





























Copyright 2003

by

Mark S. Lander




























This project is dedicated to my parents Donald W. Lander, and Betty M. Lander. Your
support has given me the ability to finish what I have started.
















ACKNOWLEDGMENTS

I would like to express my deepest appreciation to my wife, Delia, daughter

Caitlin, and son Kyle. This project was made possible with their love, support, and most

of all patience.

A special thank you goes to Larry "Rex" Ellis. His assistance on this project goes

beyond what any normal individual would have contributed. I thank him for being a

great friend.

I would also like to thank my graduate committee: Dr. Ann Wilke, Dr. Randy

Brown, Dr. Richard Schneider, and especially Dr. Mary Collins, committee chair. Their

patience, understanding and insight have greatly influenced the outcome of this work. As

I have now found out, it is not easy raising a family, working 40 hours a week, and

conducting research.

For technical assistance I would like to thank Larry Schwandes, and Tom Lounga,

for their help with laboratory procedures; Tom Seal, from the Department of

Environmental Protection, for valuable documents; Andy Reich and Dr. Stephen Roberts

for their time concerning toxicological interpretations; and my employer, the Alachua

County Health Department, for allowing me the time to complete this degree.
















TABLE OF CONTENTS

Page

A C K N O W LE D G M EN T S ....................................................................... .................... iv

L IS T O F T A B L E S ................................................. .................................................... viii

LIST OF FIGURES ....................................................................................... ix

INTRODUCTION ..................... ... ................................................. .. 1

U rban Storm w ater R unoff ........................................................................ ................... 1
Florida's Stormwater Management Program............................................................ 2
Storm w ater M anagem ent System s........................................................... .................... 4
D eficiencies in Storm w ater Regulation ............................................. ...................... 4
R research S ite ............................................................................................................. 5
O overall R research O bjectives.................................................................... .................... 7


L IT E R A T U R E R E V IE W ........................................... ............................ ....................8...

Characteristics of Urban Stormwater Runoff ................................................................. 8
Methods of Stormwater Management Control ............................................................ 9
Evolution of the Florida Urban Non-Point Source (NPS) Management Program........ 12
Regulation of Stormwater in Alachua County........................................................ 15
Local G overnm ental Regulations ................................................ ................... 15
W ater M anagem ent D districts ....................................................... ................... 16
Pre-Stormwater Retention Basin Soil Quality........................................................ 20
Permitting of the Retention Basin at the NATL ..................................................... 24
Review of Past Stormwater Management Studies In Florida........................ 25
Criteria Used in Metal Contamination Analysis..................................................... 27
Chapter 62.777 F.A.C. Contaminant Cleanup Target Levels............................. 27
Soil Quality Assessment Guidelines (SQAGs)................................................... 29
Baseline Concentrations for Trace Metals in Florida Soils ................................... 30
M etals .......................................................................................................... ............ 3 1
C adm ium (C d) .............................................. ... ........................... .................... 32
C hrom ium (C r).......................................................................................................... 33
C opp er (C u ) ............................................................................. .... ....... ......... 34
L ead (P b )................................................................................................................... 3 5
N ick el (N i) ................................................................................................................ 3 6
Z in c (Z n ) ................................................................................................................... 3 7









Metal Attenuation in Stormwater retention Basin Sediments.................................... 38


OBJECTIVES .......................... .............. .................................... 41

Objective 1 Evaluation of Current Soil Conditions for Future Studies.................. 42
Objective 2 Comparison of Current Metal Concentrations in Basin Soils to Soil
T arget C leanup L ev els .................................................................... ......................... 42
Objective 3 Comparison of Current Metal Concentrations in Basin Soils to Soil
Q quality A ssessm ent G guidelines .................................................................................... 42


M A TERIA LS AN D M ETH O D S............................................................. ..................... 44

Site D description ... ........................................................................... .................... 44
Sam pling L locations ......................................... ... ........................... .................... 51
Field Procedures .......................................................................................... 57
L laboratory Procedures ......................................... ............................ .................... 57
M etal A analysis ............................................. ... ........................... .................... 58
O rganic C arbon C ontent ................................................................. .................... 58
O rganic M atter C ontent .................................................................. .................... 59
Particle-Size D distribution ................................................................ .................... 59
pH Analysis .................................................................................... 59
Statistical M ethods ............................................. ... ...... ............... .................. .. 60
E stim ating M etal Loading R ates............................................................ .................... 60


R E SU L T S ......................................................................................................... ........ .. 62

O rganic M atter C ontent ...................................................................... .................... 63
O rganic C arbon C ontent ..................................................................... .................... 65
Soil pH .............................................................. ........................... 65
P article-Size D distribution .................................................................... .................... 68
M etals: Cadm ium ................................................................. 69
Cd vs. Baseline C concentration Levels ............................................... .................... 69
Cd Concentrations Compared With Various Screening Levels............................. 69
M etals: C hrom ium (C r)................................................................................................. 74
Cr vs. B aseline C concentration Levels....................................................................... 74
Cr Concentrations Compared With Various Screening Levels .................... 74
M etals: C opper (C u) ........................................................................... .... .............. ... 79
Cu Vs. Baseline Concentration Levels ............................................................... 79
Cu Concentrations Compared With Various Screening Levels.............................. 79
M etals: L ead (Pb)............................................................................... .. .. ................... 84
Pb V s. Baseline Concentration Levels............................................. ................... 84
Pb Concentrations Compared With Various Screening Levels..................... 84
M etals: N ickel (N i) ........................... ................................... 88
N i V s. B aseline C concentration Levels .................................................... ............... 88









Ni Concentrations Compared With Various Screening Levels .............................. 88
M etals: Z inc (Z n) ....................................................................... ......... ..................... 92
Zn V s. Baseline Concentration Levels.............................................. .................... 92
Zn Concentrations Compared With Various Screening Levels.............................. 92
L inear R egression A analysis .................................................................. .................... 96


DISCU SSION .......................... ... .............. ............................................97

Sim ple Linear R egression .............................................................. ................... 104
M etal L oading R ates ......................................... ............................. ................... 106


RECO M M EN D A TIO N S ................................................................... .................... 113

APPENDIXES

A ACRONYM LIST OF AGENCIES AND PROGRAM AREAS .............................. 116

B A D D ITIO N A L FIG U R ES ............................................................ ....................1..... 18

C ANALYTICAL RESULTS ................................................124

D REGRESSION ANALYSIS ................................................136

REFERENCES ............................. ............. ................................. 141

BIO G RA PH ICA L SK ETCH ............................................................. ..................... 145

























vii
















LIST OF TABLES


Table Page

1. Soil clean-up target levels (SCTLs) for contaminated soils ...........................................28

2 Soil quality assessment guidelines for heavy metals in study. ....................................30

3. Baseline concentration for Florida Surface Soils.................................... ..................... 31

4. Sample site status for each cell evaluated.................... .................... 56

5. Sedim ent analysis and m ethods used in study ........................................ ..................... 58

6. M etal concentrations in stormwater runoff.................... .............................................. 111

7. L-THIA generated loading rates compared to estimated total mass in SEEP ................111

A-1. Comm on acronym s used in this text.................... ................................................. 117

C-1. Particle-size analysis for cell 1 ............................................ 125

C-2. Particle-size analysis for cell 2 ............................................. 126

C-3. Particle-size analysis for cell 3 and control site............................ ........................ 126

C-4. Laboratory analysis for percent organic carbon (%OC), percent organic matter
(% O M ), and pH ................ ......... ..... ... .................................. 127

C -5. M etal C concentrations ........................................ ............................ .................... 129

C-6. Metal concentrations compared to regulatory guidelines........................................130

C-7. Regression analysis on all sites, n = 38. .................. ........................ 132

C-8. Regression analysis on all sites 0 5 cm n = 19.......................... ........................ 133

C-9. Regression analysis on all samples, 5 10 cm, n = 19............................................134

C-10. Regression analysis on cell 1, 0 5 cm, n = 12.......................................135
















LIST OF FIGURES


Figure Page

1. Increased stormwater runoff expectations due to the loss of permeable soil surfaces .....2

2. Current agency infrastructure with respect to stormwater regulations..........................3...

3. Photograph of the stormwater management system at the Natural Area Teaching Lab...6

4. The location of the Stormwater Ecological Enhancement Project (SEEP) ...................17

5. Photograph of four-board fence bordering the eastern and northern region of the
stormwater retention basin at the Natural Area Teaching Lab .....................................20

6. D iagram of storm w ater basin.................................................................. ..................... 21

7. Location of Retention Basin at Natural Area Teaching Lab...........................................44

8. Layout of N natural Area Teaching Lab.................................................... ..................... 45

9. Photograph of stormwater runoff collection area covered with debris..........................46

10. Natural areas and parking surfaces draining to the retention basin............................. 47

11. Original design of stormwater retention basin before enhancement project began........49

12. Diagram of the retention basin post enhancement that occurred in 1998....................50

13. Breakdown of the sample cells inside the stormwater retention basin........................51

14. Location of sample sites in the stormwater retention basin..........................................54

15. Sample site locations for the stormwater management system.. ................................. 55

16. Percent organic matter in soils within the stormwater retention basin........................64

17. Soil pH at locations within the stormwater retention basin..........................................67

18. Cadmium concentrations in the stormwater basin soils.............................................71









19. Location of sites where cadmium concentrations were detected above threshold
effects levels (T E L s). .............................................. ................................................. 72

20. Comparison of cadmium concentrations to screening criteria throughout the entire
basin .................................................................................................................... 73

21. Chromium concentrations in the stormwater retention basin soils..............................76

22. Location of sites where chromium was detected above contaminant screening levels.. 77

23. Comparison of chromium concentrations to screening criteria throughout the entire
basin .................................................................................................................... 78

24. Copper concentrations in the stormwater retention basin soils. ...................................81

25. Location of sites where copper was detected above contaminant screening levels........82

26. Comparison of copper concentrations to screening criteria throughout the entire
basin ............................................................................................... 83

27. Lead concentrations in the stormwater retention basin soils. ........................................85

28. Location of sites where lead concentrations were detected above threshold effects
levels (TEL's) ..................... ... .............. .............. .................... 86

29. Comparison of lead concentrations to screening criteria throughout the entire basin....87

30. Nickel concentrations in the stormwater retention basin soils.....................................89

31. Location of sites where nickel concentrations were detected above threshold effects
levels (TEL's) ..................... ... .............. .............. .................... 90

32. Comparison of nickel concentrations to screening criteria throughout the entire
basin ............................................................................................... 91

33. Zinc concentrations in the stormwater retention basin soil. .........................................93

34. Location of sites where zinc was detected above contaminant screening levels.............94

35. Comparison of zinc concentrations to screening criteria throughout the entire basin....95

36. Diagram of the SEEP with areas of concern and short-circuiting path highlighted.......100

37. GIS photograph of the area adjacent to the stormwater retention basin.......................107

38. GIS land use classification designations for the areas surrounding the retention
basin ............................................................................................... 108

39. GIS designated land use classes within the retention basin watershed........................ 109









40. GIS soils layer added to land use classifications. ....................................110

B-1. 1988 proposed retention basin with soil boring locations. ......................................119

B-2. Soil boring locations 1 -4. Borings conducted in 1988 by Bishop Beville for the
U n iv ersity of F lorid a ........................................................................... .................... 12 0

B-3. Soil boring locations 5 -8. Borings conducted in 1988 by Bishop Beville for the
U n iv ersity of F lorid a ........................................................................... .................... 12 1

B-4. Soil boring locations 9 12. Borings conducted in 1988 by Bishop Beville for the
U n iv ersity of F lorid a ........................................................................... .................... 12 2

B-5. Soil boring location 13. Borings conducted in 1988 by Bishop Beville for the
U n iv ersity of F lorid a ........................................................................... .................... 12 3

D-1. Regression curve for Cr, Ni, Pb, and Zn; all points observed. .......................... 137

D-2. Regression curve for Cr, Ni, Pb, and Zn, with outliers removed....................... 138

D-3. Regression analysis for Pb and Ni in the top 5 cm of soil for every site throughout
the entire basin ................................................................ ............... 139

D-4. Regression analysis for Pb and Ni in the top 5 cm of soil for sites located in cell 1... 140
















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

EVALUATION OF SELECTED HEAVY METAL CONCENTRATIONS
IN SOILS OF AN URBAN STORMWATER RETENTION BASIN

By

Mark S. Lander

December 2003

Chairman: Mary E. Collins
Major Department: Soil and Water Science

Treatment and disposal of urban stormwater runoff have become major concerns

when attempting to protect our surface and groundwater resources. Regulatory practices

of the past were developed as watershed management tools, placing minimal emphasis on

stormwater pollutant loads. Today, though, advanced studies in stormwater collection

have shifted focus from a water quantity control issue to that of water quality. Currently

the Florida Department of Environmental Protection, all five Water Management

Districts, and local governments are working together to develop safe stormwater

management regulations. With basin design being orchestrated for maximum water

quality treatment, the soil becomes an integral part of system construction. However, the

soils efficiency for pollutant removal from surface water may decrease overall soil

quality, in turn promoting an unsuitable environment within the basin for the existing

ecosystem. Degradation of soil quality through pollutant accumulation raises issues on

basin remediation and soils handling and disposal.









This study was done to evaluate the condition of soils inside a constructed

wetland detention basin at the Natural Area Teaching Laboratory (NATL) site in

Gainesville, Florida. Sampling was conducted inside the retention basin with the soils

being analyzed for field parameters and heavy metal contaminant concentrations.

Selected contaminant concentrations for Cd, Cr, Cu, Ni, Pb,and Zn were measured and

their distribution within soils of the wetland basin studied.

The results indicated that metal concentrations in the upper 10 cm of the

stormwater basin soil varied for Cd (0.0 mg/kg 2.5 mg/kg), Cr (12.0 mg/kg 262

mg/kg), Cu (3.0 mg/kg 235 mg/kg), Ni (4.0 mg/kg 31.5 mg/kg), Pb (0.5 mg/kg 64.5

mg/kg), and Zn (6.5 mg/kg 720 mg/kg). Several of these sites exceeded soil quality

reference guidelines used for contamination assessments. The majority of the

contamination lay adjacent to stormwater inlet pipes in the constructed wetland. The

proximity and extent of metal concentrations did not suggest their migration outside of

the constructed wetland.
















INTRODUCTION


Urban Stormwater Runoff

Urban stormwater runoff has long been considered a major contributing factor of

non-point source pollution to both surface and groundwater resources. The loss of

permeable soil surfaces through urbanization can be expected as Florida's population is

calculated to reach above 20,000,000 by the year 2020 (Florida Department of

Environmental Protection, 2001). As land becomes covered with impervious barriers

such as concrete and asphalt, infiltrative soil pathways become blocked, generating an

increase in stormwater runoff during rainfall events. Estimations made by the Florida

Department of Environmental Protection (FDEP), indicate that a 10% to 20% increase in

impervious surface area can double the amount of stormwater runoff generated during a

rainfall event (Livingston and McCarron, 1991). Stormwater runoff can reach as high as

55% of the total rainfall event if between 75% and 100% of land surfaces become

covered due to urbanization (Figure 1).

When exposed to impermeable surfaces, stormwater runoff collects materials

deposited between past rainfall events. Runoff from impermeable surfaces has been

shown to contain significant amounts of hazardous contaminants, such as heavy metals,

petroleum hydrocarbons, pesticides and many other types of organic chemicals (Cox et

al., 1998). Previous research has shown variability in contaminant concentrations at the

same site over time (Livingston and Cox, 1995). It is this unpredictability that makes







2


urban stormwater runoff an environmental threat. Without knowing the extent or even

the kinds of contaminants in urban stormwater runoff it is difficult to assess the

environmental implications that may be occurring. It is this same variability that makes

establishing proper regulatory guidelines for the management of urban stormwater so

important.


Figure 1. Increased stormwater runoff expectations due to the loss of permeable soil
surfaces (Diagram taken from The Florida Department of Environmental Regulation
reference manual, Stormwater Management, A Guide for Floridians, Livingston &
McCarron, 1991.)


Florida's Stormwater Management Program


The current state infrastructure for urban stormwater management consists of a

multi-agency coalition between the Florida Department of Environmental Protection

(FDEP), Florida's five regional Water Management Districts (WMDs), and local

governmental agencies (Figure 2). The FDEP serves as the umbrella agency for urban

stormwater regulation by implementing the state's Non-Point Source Management

Program (NPSMP) (Cox et al., 1998). Regional regulation of the NPSMP has been


10% 20% IMPERVIOUS SURFACE


35% EVAPO-


75% 100% IMPERVIOUS SURFACE


NATURAL GROUND COVER


35% 50% IMPERVIOUS SURFACE









delegated to the WMD's allowing for more flexibility to address centralized issues

through regional goals & policies. Local government has the responsibility for adopting

comprehensive land use plans in accordance with the state's land planning agency, the

Florida Department of Community Affairs (DCA). By developing and implementing

stormwater master plans addressing current and future growth expectations local

governments have the ability to establish controls for monitoring the operation and

maintenance of stormwater collection systems. In addition to their regulatory capacities,

local governments have been given the authority to establish stormwater utilities fees

creating funding sources for local stormwater programs, thus making cities less

dependent upon state funding for program implementation.


Figure 2. Current agency infrastructure with respect to stormwater regulations.


The Florida Department of Environmental Protection
(Non-Point Source Management Program)





Florida's Five Regional Water Management Districts
(Regional Goals Addressed Through Watershed
Management)




Local Governmental Agencies
(Regulation Through Local Comprehensive Plans)









Stormwater Management Systems

With the regulatory controls in place, urban stormwater runoff is addressed under

the NPSMP by the use of stormwater management systems. Common types of these

include retention or detention type basins. These systems are designed to collect, hold

and treat stormwater before reaching its final destination, whether it is ground or surface

water recharge. Older stormwater basins were designed for water storage with little

attention being placed on treatment (Athayde et al., 1983). New basin construction and

some older retention basins are being redesigned using Best Management Practices

(BMPs) within the stormwater management system, such as grassed swales and

constructed wetlands to treat stormwater pollutants. Vegetation and soils in combination

with varied water retention periods may play a major role in cleansing pollutants from

stormwater entering these systems.


Deficiencies in Stormwater Regulation

Over the past 30 years the focus of stormwater management has shifted from a

water quantity based approach to that of overall water quality. Current regulations

address criteria that must be met for the storage capacity of stormwater basins and for

water quality in systems that discharge to surface waters. Pollutant toxicity build up in

stormwater basin soils is not addressed, unless the soils are being considered for land

application or landfill disposal. Even these concerns have led to only unofficial disposal

requirements.

It's the soil's ability to partition certain pollutants that make it both desirable and

hazardous to the ecosystem of the overall stormwater management basin. Without proper

controls, excessive pollutant loading of soils in stormwater basins may lead to elevated






5


levels of contamination, that under certain environmental conditions could become

available for exposure to humans, aquatic organisms and other various wildlife species.

Livingston and Cox (1995) studied sediment toxicity buildup in stormwater basins to

establish guidelines for sediment disposal. This study was expanded upon in 1998

looking at comparisons of pollutant buildup over time in basin sediments to the specific

land use category. The recommendations for remedial action as a measure of loading

time were difficult to assess due to sampling inconsistencies between locations. It was

determined that more data would be required before sediment disposal guidelines can be

established (Cox et al., 1998).

The argument opposing soil toxicity concerns is supported by the ideology of

presumptive operation and maintenance. That is, stormwater retention basins are

designed to collect and treat runoff before it is allowed to re-enter a clean water source.

With loading of stormwater basin soils by contaminants assumed, and as long as the

basin is being maintained and operating as originally permitted, the contamination

becomes a function of the permit (Still, 2000). A second reinforcing factor to this

argument is that, in general, stormwater basins are not created for, or intended to be part

of a human/wildlife exposure scenario. As the use of integrated wetlands in stormwater

treatment basins become more prevalent, however, this interaction becomes inevitable.


Research Site

The stormwater retention basin at the Natural Area Teaching Laboratory (NATL),

located on the campus of the University of Florida, is representative of how the second

assumption in regards to stormwater contaminant issues may be flawed. The basin,

which first was designed to collect and treat stormwater for disposal through slow soil









infiltration, initially had minimal emphasis on vegetative or ecological communities

Through redesign, however, this basin has now become an integrated wetland, creating

an attractive environment for wildlife such as alligators, wading birds, and other avian

species (Figure 3)

In addition, the University of Florida has begun to use this facility as an

interactive research site Previous literature suggests, that while constructed wetlands

have become effective BMPs for secondary wastewater treatment, their ability to treat

urban stormwater runoff has not been extensively studied (Carleton et al, 2000) This

site offers researchers the ability to assess basin performance and the effectiveness of

various wetland species and basin design with respect to stormwater treatment By

making this site available for study and creating a desirable environmental habitat

through vegetative cover and water resources, exposures to possibly harmful levels of

toxic contaminants becomes an issue


Figure 3 Photograph of the stormwater management system at the Natural Area
Teaching Lab, looking south









Overall Research Objectives

There are currently no regulations requiring monitoring of stormwater retention

basin soils for contaminant build-up. A practical solution, may be to increase public

awareness on stormwater constituents, and their ability to accumulate in these basins. In

addition, the owners of these systems may not realize the potential exposure hazards that

exist. The objectives of this study were developed around the lack of regulatory

requirements for stormwater basin soils, and public awareness.

First, by evaluating soils throughout the basin for metal concentrations, organic

matter content, organic carbon content, pH, and particle size, issues concerning health

implications not currently considered in basin permitting considerations could be

addressed.

A second goal of this study was to generate background data on the stormwater

retention basin for the University of Florida to use with future studies at the research site.

These data could provide valuable information for evaluating wetland efficiency in

treating stormwater, as well as in providing insight to the current condition of the basin.

Soils play an integral role in determining how various land developments may

proceed. On some occasions short-term treatment capabilities of soils are considered for

permitting possibly overlooking long-term effects. Therefore, a third outcome of this

study is to increase awareness on soil contamination in stormwater management systems.

Understanding of such systems can lead to protective measures which can create a safe

working environment for all.

Throughout this document, a number of acronyms are used for various agencies

and technical documents. A table defining all acronyms used in this thesis can be found

in Appendix A.
















LITERATURE REVIEW


Characteristics of Urban Stormwater Runoff

Improper management of stormwater runoff from urbanized areas can have a

downstream affect on both ground and surface water resources. Focus of stormwater

regulation in the past had been limited to issues of sediment control or flood relief.

Today this regulatory trend is shifting towards a water quality approach, recognizing the

many different pollutants carried within stormwater (Athayde et al., 1983).

A study released by the Nationwide Urban Runoff Program (NURP) in 1983,

detailed a variety of stormwater pollutants being identified in urban runoff. Two of the

primary contaminants detected were heavy metals and organic priority pollutants, such as

pesticides and volatile organic.

Results from the NURP study indicated that heavy metals were more frequently

detected in stormwater runoff than any other priority pollutant. While all of the 13 metals

on EPA's priority pollutant list were detected in runoff analyzed for this study, copper,

lead and zinc had the highest detection percentage, found to be present in at least 91% of

the samples. In some instances concentrations were detected above freshwater acute

criteria and federal drinking water standards (Athayde et al. 1983).

Organic pollutants were not detected at the same frequencies as the metals.

Volatiles, pesticides, and phenols made up the majority of organic priority pollutants

detected. Detection values ranged from 22% of the samples to less than 10% for others.









A possible limiting factor for detection may have been that the monitoring scheme used

allotted only a limited number of priority pollutant samples taken (Athayde et al., 1983).

Further contaminants noted during the study were coliform bacteria, nutrients, oxygen

demanding substances, and total suspended solids (TSS). Additional studies have

indicated that copper, zinc, cadmium, lead, and possibly nickel, are major components of

pollution from urban stormwater runoff (Mikkelsen et al., 1997).

There is difficulty in predicting pollutant loads within urban stormwater runoff.

Variability of pollutant concentrations have been seen at a particular site from one storm

event to the next (Athayde et al., 1983). Another factor determining variability may be

seasonal influences. Higher concentrations of pesticides may be detected in stormwater

runoff during warmer months, when land application increases. In contrast, volatile

components may decrease during summer as the temperature controls volatility (Fischer

et al., 2003). With stormwater runoff, the goal is to direct flows from watershed areas to

a defined boundary for isolation and treatment. Retention basins may act as a pollutant

trap for various contaminants through soil adsorption and volatilization, other more

soluble contaminants may pass through these systems to groundwater (Mikkelsen et al.,

1997).


Methods of Stormwater Management Control

As our knowledge of identified pollutants carried within urban stormwater runoff

increases, and we determine the threats that they may pose to natural resources, questions

on how to control this problem must be addressed. The current response is to mix

methodologies of the past with the concept of best management practices (BMPs). In









some instances there may not be one solution to a stormwater runoff problem, but instead

a variety, or train of applications may exist within a single stormwater system.

Best Management Practices can be separated into two distinct categories; non-

structural, and structural. Non-structural BMPs rely heavily upon public education and

regulatory controls for effectiveness. Making consumers aware of potential impacts from

everyday household chemical usage, may lead to less overuse or abuse. Additionally,

regulatory constraints along with proper planning can control materials and in turn

develop acceptable guidelines for application (Lawrence et al., 1996).

Structural controls are methods used in stormwater systems to reduce the impacts

of erosion, flooding, and the magnitude of pollutant loading to waters. Methods of

structural controls are developed around the collection and containment of stormwater to

allow for settling and filtration, as well as chemical and biological treatment. The

particular methods used in structural controls should be designed around site specific

characteristics.

In Florida, particularly in the southern part, high wet season water tables create a

need to protect groundwater supplies from contamination by polluted stormwater runoff.

In these areas, the most common type of stormwater management systems are retention

or detention type basins (Rushton & Dye, 1993). Retention basins are designed to collect

and retain stormwater runoff on site. The processes of treatment are infiltration through

the soil and loss through evaporation. Detention basins are similar to retention, in the

aspect of stormwater collection, but in fact, their primary objective is to act as temporary

storage of stormwater before releasing it to a downstream water body. Extended

stormwater residence times between 24 and 48 have been shown to be effective in









allowing for sedimentation of suspended particles and microbiological treatment of

stormwater contaminants. Both retention and detention basins have been shown to

remove metals from stormwater with an efficiency between 60 and 80% (Lawrence et al.,

1996).

In some instances more than one BMP is used in a single stormwater treatment

system. Examples of other methods include percolation trenches, grassed swales,

pervious pavement, vegetative waterways, and street sweeping. Many of these methods

rely heavily upon either quick infiltration or vegetative species to reduce pollutant loads.

One emerging BMP in stormwater treatment is the usage of wetlands in combination with

retention or detention systems.

Studies have indicated the ability of wetlands to act as a filter or sink for

stormwater pollution either through sedimentation or soil adsorption, while providing

flood protection. The dominant process in pollutant removal from stormwater may be

sedimentation, however, indications are that vegetation and sediment/organic matter

relationships can be important in providing sites for metal precipitation (Walker and

Hurl, 2002). Goulet and Pick (2001), studied the effects of cattails on metal

concentrations and partitioning in surficial sediments of a wetland basin. Their study

indicated that the presence of cattails did not appear to have an affect on metal

concentration or partitioning of metals within the stormwater sediments. It did show that

areas where cattails were present tended to have higher organic content within the

sediments than zones where emergent vegetation did not exist.

Cheng et al. (2002) evaluated the metal uptake in the tropical-subtropical swamp

species C. alternifolius and V. exaltata. Contaminated stormwater passing through a









wetland planted with the species experienced heavy metal removal rates at approximately

100% from inflow effluent metal concentration to water exiting the system. A

comparison was made between metal accumulation in the soils and plants. C. alternifolius

proved to be an efficient vegetative species for removing heavy metals. In addition to its

ability to uptake pollutants, many plants store these contaminants in underground organs,

but C. alternifolius stores them in lateral roots forming just below the soil-water interface.

This makes it necessary to remove only a few cm of contaminated soil when attempting

site remediation (Cheng et al., 2002). Further studies using both floating and emergent

vegetation have shown similar results of heavy metal removal, reducing their

concentrations to an average of 85% (Kao et al., 2001). With removal of contaminants

being a primary focus on environmental protection, we might expect to see more systems

relying on vegetative wetlands as a BMP style.


Evolution of the Florida Urban Non-Point Source (NPS) Management Program

In Florida, increasing concerns of surface and ground water degradation through

contact with contaminated urban stormwater has led to changes in the methodology for

stormwater disposal. In the past, urban stormwater runoff was addressed as a water

quantity problem, controlled by collection and storage methods. However, by the mid-

1970s evidence was present indicating that over half the pollutant load entering Florida

waters came from non-point source runoff (Rushton et al., 1993). To combat the

concerns of pollutant loading to water resources from urban stormwater runoff, Florida

developed a comprehensive watershed management program involving federal, state,

regional, and local governments.









Regulation of urban stormwater runoff is vital in preserving Florida's

environmental resources. Up until 1960, water quality effects from stormwater pollution

received little attention (Athayde et al., 1983). From 1960 until the early 1970s, studies

began to address pollutant identification in stormwater, but little significance was given

to developing specific discharge requirements. In 1972, the Federal Clean Water Act was

amended to prohibit the discharge of any pollutant to navigable waters unless authorized

by a National Pollutant Discharge Elimination System (NPDES) permit. Non-point

source pollution was now being recognized as a major contributing factor to water quality

problems. With the promulgation of EPA's first stormwater regulations in 1973, urban

runoff was exempted unless coming from an industrial or commercial process containing

known contamination. In addition, regulation of the smaller urban stormwater discharges

was left up to state and local governments.

The lack of direction in stormwater management in the mid-1970s led to initiation

of the Nationwide Urban Runoff Program (NURP). The goals of the NURP were to

provide all levels of government with management options for handling polluted

stormwater discharges. It was these national investigations along with various Florida

studies, which laid the foundation for Florida's Urban Stormwater NPS program.

In 1979, Florida's first stormwater rule, Chapter 17-4.248, F.A.C., was

implemented by the Department of Environmental Regulation (DER). Under this

Chapter, the issuance of stormwater permits was dependent upon the "significance of

discharge. Variability in the determination of "significant" by regulators made this an

impractical approach. The state's Environmental Regulation Commission adopted a

revised stormwater rule, Chapter 17-25, F.A.C., in 1982. Past concerns of









inconsistencies in permitting were addressed by requirements for permits on all new

stormwater discharges and for modifications to existing discharges where pollutant loads

increased (Florida Department of Environmental Protection, 1993). With the adoption of

the revised chapter, Florida became the first state in the country to require the use of

BMPs as a practical method of stormwater treatment. In effect, performance based

standards established in Chapter 62-40, F.A.C., were set to control quantity and quality of

stormwater discharges, with emphasis placed on water quality exiting the system.

From 1984 to 1986 the focus of regulation shifted from state to regional. The

Southwest Florida Water Management District (SWFWMD), St. Johns River Water

Management District (SJRWMD), and Suwannee River Water Management District

(SRWMD) adopted regulations in line with DER stormwater rules, allowing DER to

delegate permitting authority to each WMD. Thus, stormwater rules were put in place to

address watershed management needs on a regional basis instead of the state as a whole.

Building upon the DER WMD stormwater permitting relationship, the Florida

Legislation modified Chapters 373 and 403, F.S. The overall effect was the combining of

the WMDs Management and Storage of Surface Waters permit with the newly formed

Department of Environmental Protection's (DEP) Wetland Dredge and Fill permit. The

combination of these two permits created what is now known as an Environmental

Resource Permit (ERP). ERPs allow either agency to evaluate both stormwater quantity

and quality impacts, depending upon the proposed development.

State and regional regulation are not the only controls when determining

stormwater project acceptability. The DCA is the agency responsible for the

implementation of the state's growth management program. Several statutes establish









goals and directives for growth management throughout Florida. Specifically, Chapter

163, F.S., contains language including the Local Government Comprehensive Planning

Act and Land Development Act of 1985. Both address local government's

responsibilities in land management, defining the requirements for the preparation of

local comprehensive plans and direction of land development. The direction of the local

government must be in conformance with the overall policies set forth by the state and

regional regulators (Florida Department of Environmental Protection, 2001).


Regulation of Stormwater in Alachua County

Local Governmental Regulations

Stormwater management systems in Alachua County are subject to review at the

local, regional, and state levels. The City of Gainesville and Alachua County each has its

own ordinance regulating stormwater management systems. City Ordinance, Chapter 27,

Article V, Section 27-238 (1998), established the formation of a water management

committee. The responsibility of the committee is to assess water quantity and quality

issues, and to assist in the development and implementation of sound water management

practices. Included issues are stormwater discharge and erosion and sediment controls in

stormwater management systems. Jurisdiction of the committee extends within the City

boundaries as well as adjacent lands, which may affect the City watershed areas. In

addition, Chapter 30, Section 30-270 (1992), addresses applicable standards for erosion

and sedimentation control, design, and maintenance of stormwater management systems.

However, the design phase defaults to existing state and WMD codes, with emphasis

based on storage capacity and discharge quality of stormwater.









Alachua County has taken a similar approach to addressing stormwater issues in

its unincorporated areas. Title 4, Chapter 44 (1996), established a stormwater

management utility (SMU) to oversee permitting outside all unincorporated boundaries.

The SMU, made up of the board of County Commissioners, is responsible for regulating

all stormwater discharges through a review of conceptual plans, proposed system usage,

required maintenance, and continued operation of stormwater management facilities. As

part of the Local Government Comprehensive Planning and Land Development

Regulation Act established under Chapter 163, F.S., Alachua County adopted Title 34,

Chapter 343 in 1992. Under 343, design, construction and operation components of

stormwater management systems are defined. As with the city ordinances, basic

regulation is adopted from state and WMD regulations. Emphasis on flood control and

storage capabilities, along with ground and surface water protection is in large the driving

force behind county regulations.

Additional local governmental regulations regarding stormwater discharges and

water quality have recently been implemented. The Alachua County Environmental

Protection Department (ACEPD) drafted a 2002 ordinance pertaining to water quality

standards and management practices for both the incorporated and unincorporated areas

of Alachua County. The ordinance, which became effective January 1, 2003, establishes

new standards defining allowable discharges to stormwater systems. Erosion and

sediment controls will be increased throughout the county, and powers of enforcement on

non-compliance or illicit activities will be given to the ACEPD.

Water Management Districts

Regional permitting for Alachua County is handled through delegation from the

FDEP to the WMDs. The majority of watershed issues in Alachua County are directed










either through the Suwannee River Water Management District (SRWMD) or the St

John River Water Management District (SJRWMD) The stormwater basin for this

research is located near the center of Alachua County in the northwestern portion of the

SJRWMD (Figure 4)


V
2
'-I---


Figure 4 The location of the Stormwater Ecological Enhancement Project (SEEP) at the
Natural Area Teaching Lab (NATL) in Alachua County



Permitting requirements for stormwater runoff in the SJRWMD are established in

several regional codes, using ERPs as the mechanisms for regulation Chapter 40C-4,









Surface Water Management Systems, establishes guidelines for the management and

storage of surface waters located within the District. The structure of these guidelines is

in accordance with FDEP standards set forth in Chapter 62-40, F.A.C., and Chapter 373,

F.S. Under Chapter 40C-4, the SJRWMD has established conditions for stormwater

permitting in addition to defining a management structure for regulatory purposes.

Taking stormwater management a step further, in Chapter 40C-42, Regulation of

Stormwater Management Systems, the District established standards to control discharges

initiated from stormwater runoff. Included within the chapter are requirements for

system design and construction, performance criteria, special exemptions, operation,

monitoring, and maintenance.

As with the local ordinances established for stormwater runoff, WMD and FDEP

regulations address mainly water storage and quality of discharge issues. Requirements

for monitoring pollutant build-up in stormwater sediments are not addressed to any

extent. To better understand the regulatory absence on soil contaminant build-up, phone

interviews were conducted with both SJRWMD & SWRMD staff. Information from the

interviews indicated that permitted stormwater management systems are inspected on a

routine basis. The emphasis of the inspections is on sediment and debris accumulations,

and structural integrity of the basin. Soil contaminant concentrations are not evaluated

unless the permitting agency has reason to suspect the basin is not functioning as it was

originally permitted. The neglect of contaminant evaluation requirements is justified by

the term "presumptive operation and maintenance." In simple terms, stormwater

retention basins are designed and constructed to collect and treat runoff for pollutant

removal before allowing infiltration to ground and surface water resources. A major









component of the treatment process is the soil's ability to filter out contaminants at its

infiltrative surface. If a stormwater system is functioning properly, then the removal of

pollutants from the water column and subsequent build-up of contaminants in the soil is

merely a function of the system. A second part of the equation of pollutant soil build-up

in stormwater management systems is the fact that these basins are not designed with the

intent of frequent human and wildlife interactions. The intent of stormwater management

is to localize contaminants by directing stormwater to a centralized location. Access to

these areas is then commonly limited or discouraged through the use of fencing or other

restrictive measures.

This last thought process is not the case with the NATL stormwater retention

system. There are no restricted barriers to limit public access, such as chain link or

stockade fences. The only defining border around the basin is a 4-board fence to the east

and north with several access points (Figure 5). In addition to not limiting access, a

boardwalk has been installed inside the stormwater basin, which allows entry to almost

the entire area (Figure 6). Additionally, basin landscaping has created an environment

that attracts and sustains a variety of wildlife. The research opportunities created by the

stormwater basin make this area a valuable site for the University. A lack of current

stormwater soils data at this location creates a great opportunity of study. It is should be

recognized though, that the absence of requirements for contaminant regulation in

stormwater basins may create a potentially hazardous working environment.









~in


Figure 5. Photograph of four-board fence bordering the eastern and northern region of
the stormwater retention basin at the Natural Area Teaching Lab.


Pre-Stormwater Retention Basin Soil Quality
Lacking actual laboratory data on the soils in the vicinity of the stormwater

retention basin, soil quality before the construction of the retention basin could only be

estimated. The control samples located outside the retention basin gave insight to surface

horizon conditions. Additionally, logs of soil borings completed during the initial

construction phase on the stormwater basin were located and compared to existing soil

maps of the area, giving a broader view of the subsurface horizons that existed pre-basin

construction (Beville, 1988).















A) B)



I ., I il

























Figure 6 Diagram of stormwater retention basin. A) Boardwalk location in the retention basin as noted by red line B) Photograph
of students using the boardwalk to enter the retention basin









Soil maps in the Soil Survey of Alachua County Florida (Thomas et al., 1985),

indicate that before this area was dedicated entirely to stormwater management the

dominant soil series in the area were Arredondo, and Kendrick. The classifications of

these soils are similar as are their parent materials. Both series are in the Ultisol order,

but the Kendrick series is classified as a loamy, siliceous, semiactive, hyperthermic,

Arenic Paleudult, indicating a shallower argillic horizon present than in the Arredondo,

which is classified as a loamy, siliceous, semiactive, hyperthermic, Grossarenic

Paleudult.

Soil borings, conducted by Dr. Bishop Beville in 1988, indicated the major soil

materials to be fine sands overlying fine sandy loam and sandy clay loam horizons.

These borings were taken at selected areas within the then proposed retention basin being

constructed around an existing natural depression. Additionally, it was noted in several

areas that the clayeyy materials" were close to the surface, indicating possible removal of

the topsoil. The sandier soils were determined to be located in the northern end of the

site, in what is now the forebay. Fine-sand textured soil material was measured to depths

of between 76.2cm to as deep as 167.6cm, with the exception of one site at the

northernmost point of the basin (Beville, 1988). The remaining fine sand horizons

became thinner as the existing pond was encroached upon. The presence of water tables

at several borings was probably due to the perching ability of the clay in the subsurface

horizons and the fact that this area, the existing pond, was the natural watershed for the

surrounding lands. These documented water tables are not typically observed in the

Kendrick or Arredondo soils. However, water tables can be present in the Millhopper

soils, which is geographically associated and classified the same as Arredondo. Another









indicator hinting to the clays ability to hold or retain water, was the identification of

redoximorphic features within and above the argillic horizons. Data from the soil boring

logs, matrix color or indicated mottless, suggested the presence of either a current or wet

season water table within 2 m at every location (Beville, 1988). A complete list of the

soil borings and a map detailing their locations within the proposed basin are in Appendix

B, Figures B-1 through B-5.

Working on the assumption that the soil series at the location of the stormwater

basin were either Kendrick, Arredondo, or Millhopper, estimates on soil quality

parameters can be obtained from Tables 15 and 18 in the Soil Survey of Alachua County,

Florida (Thomas et al.., 1985).

The soil survey gives estimates in the ranges in organic matter content for the

surface horizons of the three soil series in question. Both the Kendrick and Arredondo

soils have an estimated organic matter content of less than 2% in their surface horizons.

The Millhopper soil has a range of 0.5-2% organic matter content in its surface horizon.

The soil survey additionally lists laboratory data from the Environmental

Pedology Lab in the Soil & Water Science Department at the University of Florida. pH

and organic carbon content are shown for different soil series. The pH for surface

horizons in these three soil series ranges from 5.6 in the Kendrick series to 6.0 in the

Arredondo soil. The Millhopper soil has a pH in the surface horizon listed at 5.9. The

subsurface argillic horizons, which are now exposed due to the creation of the stormwater

basin, would have a pH range of 5.2-6.0 in their original pedogenic stages. Organic

carbon content in the surface horizons of these soils ranges from 0.15% in the Arredondo

soil to 0.57% in both the Kendrick and Millhopper soils. With increasing soil depth,









organic carbon content decreases. In the Millhopper soil, the organic carbon content

decreases to approximately 0.03% in the Btg horizon, while the organic matter content of

the Bt horizon in the Kendrick soil is between 0.13-0.15%. The Arredondo soil shows a

range of 0.06-0.09% organic carbon content in the Bt horizons.

It should be noted that these numbers are not absolute for the soils that were

present in the area of the stormwater basin before its construction. However, by using

these as a reference point and comparing them to current conditions, insight on

anthropogenic influence from urbanization can be observed.


Permitting of the Retention Basin at the NATL

The retention basin serving the NATL was first permitted by the SJRWMD in

1988 under the University of Florida Master Drainage Plan as Basin #8. The original

design criterion was based on stormwater collection from a 14.45 ha watershed.

Stormwater runoff from a 100-year storm event based on a 24-hour period was calculated

to be 18,855 m3 for this watershed. Additional runoff from the Entomology/Nematology

Building and from the Florida Department of Transportation (FDOT) Park 'N' Ride lot,

serving the University of Florida, was directed to the basin in 1990, bringing the entire

watershed area to approximately 16.19 ha, increasing the total runoff flows to31,075 m .

A note to the master plan indicated the proposed maintenance of the system to include

monthly inspections, and inspections after each major storm event for debris and erosion.

Additionally, silt removal from the basin bottom in the areas of the outfall locations was

to be completed twice a year. There was, however, no reference to the evaluation of soil

sediments for contaminant build-up. In 1996, SJRWMD permit #40-001-0029AG, was

issued for the re-contouring of the SEEP due to the system being redesigned with the









constructed wetland. Under this permit, conditions of the original application were

maintained with no requirements for sediment analysis. Basin function evaluation on

storage capabilities and structure continued to drive the permitting side of UF Basin #8.


Review of Past Stormwater Management Studies In Florida

Over the past 10 years there have been a number of stormwater studies in Florida

that have led to either direct or indirect regulations being applied to permitting practices.

These studies have included evaluations on BMP styles, treatment capabilities of

differing basin classifications, and land use impacts on stormwater quality. With

emphasis in these studies being placed on water quantity and quality, soil evaluation for

contaminants many times is looked at as a side note. In 1995, however, DEP completed

an intensive literature review and monitoring project of stormwater systems across

Florida. When DEP completed its literature review, it was noted that existing data on

stormwater sediment characterization was sparse and not easily correlated due to

variation in sampling methodologies (Livingston et al., 1995). From the data obtained in

previous studies, and those collected during the course of the 1995 investigation, DEP

evaluated stormwater sediments from over 87 sites, from differing land use

classifications, within Florida. Sediment screening took place for a total of 168 different

pollutants, including pesticides, organic contaminants and trace metals (Cox and

Livingston., 1995).

Metals in the DEP study were evaluated for their concentrations and ability to

leach from soil to solution. Pollutant comparisons were made to several different state

regulations regarding soil contamination and cleanup. The six most common metals

found during this study were chromium (Cr), lead (Pb), zinc (Zn), copper (Cu), cadmium









(Cd), and nickel (Ni). Concentrations of Cr, Pb, and Zn were detected at 100% of the

sites. Cu was next with a 94% detection level, then Cd, followed by Ni, with 72% and

67% concentrations, respectively. It was noted that as a group metals were the most

frequently detected runoff related pollutant identified during this study (Cox et al..,

1998). When compared to Soil Cleanup Target Levels (SCTLs), of the six most

commonly identified metals, only Pb exceeded these parameters at a frequency of 3.5%.

For leachability, Pb exceeded criteria at 80% of the sites, followed by Cr in 9%, and Cd

in 6% of the samples. In terms of the Sediment Quality Assessment Guidelines

(SQAGs), Pb was the most problematic metal, exceeding standards at 39% of the sites.

Pb, Cu, Zn, and Cd were also identified in 22% to 11% of all samples screened. The

majority of contaminants detected above cleanup criteria during this study were

distributed within the first 2.54 cm of soil, except for Pb, which was identified exceeding

cleanup criteria at a depth of 20.32 cm.

Information obtained from the 1995 study and 1998 final report indicated the need

for future studies in soil contamination to develop adequate disposal guidelines.

Environmental protection values, such as those established in the SCTLs, and the

SQAGs, are currently applied indirectly when considering stormwater soil disposal. It

was also noted that past recommendations for soil removal based on accumulation rates

did not address variable loading rates due to land use category. It suggested more data be

accumulated to develop guidelines for proper soil removal periods. While the main intent

of this past research was to evaluate soil contamination for disposal purposes, the

concentrations and frequencies of several contaminants warrant further investigation into

the potential of acute and chronic effects on organisms from stormwater soils.









Criteria Used in Metal Contamination Analysis

Due to the absence of direct regulatory requirements for metal concentration

build-up in stormwater basin soils, evaluation of contaminant levels was accomplished

through applying several state regulations and guidelines that indirectly impact

stormwater maintenance facilities. To evaluate sediment contamination in relation to

human and wildlife concerns, SCTLs referenced in Chapter 62-777, F.A.C. were

observed. In addition, SQAGs developed for Florida's coastal waters were used to

evaluate metal concentrations in relation to the aquatic environment. Both sets of these

comparative values have been used in other studies similar in nature to the NATL

stormwater basin evaluation. In addition to regulatory standards, baseline concentrations

for trace elements in Florida surface soils established by Chen et al..(1999) were

reviewed.

Chapter 62.777 F.A.C. Contaminant Cleanup Target Levels

Values obtained in this chapter apply directly to sites governed by the terms of a

brownfield site rehabilitation agreement, pursuant to Chapter 62-785, F.A.C., and to

contaminants of concern defined under Chapter 62-770, F.A.C., Petroleum

Contamination Site Cleanup Criteria, Chapter 62-782, F.A.C., Dry-cleaning Solvent

Cleanup Criteria, in addition to the treatment of soils permitted under Chapter 62-713,

F.A.C., Soil Treatment Facilities (Florida Department of Environmental Protection,

1999). It should be noted that these values are intended for application only to sites

governed under the above referenced chapters. While they do not reference stormwater

soils, they are sometimes applied, however, when stormwater basin soil disposal options

are being considered (Livingston and Cox, 1995).









SCTLs for metals established in Chapter 62.777, F.A.C., have been separated into

two categories (Table 1). Each category defines differing levels of health protection

based on exposure criteria, such as dermal contact, ingestion, and inhalation. In addition,

variables such as body weight, exposure frequency, and exposure duration were all used

when developing the model for acceptable risk-based concentrations of contaminants in

soils.

The first, and more stringent of the two categories are the residential-based

exposure values. The greater level of protection for these comes from their availability of

access to the general public, such as children. The increased protection factor is based on

the fact that these sites are open to the public, and can be frequented by individuals with

no limited access. For this study, these values were applied when considering exposure

of contaminants to both human and wildlife communities in the area.

The second category, defined as commercial/industrial-based exposure values,

offers a lesser degree of protection. However, this is based on the assumption that access

to commercial sites is limited to the public, and exposure times could be regulated for

individuals working in these areas.




Table 1. Soil clean-up target levels (SCTLs) for contaminated soils

Contaminant Residential Exposure (mg/kg) Commercial Exposure (mg/kg)
Cadmium 75 1300
Chromium 210 420
Copper 110 76,000
Lead 400 920
Nickel 110 28,000
Zinc 23,000 560,000









Soil Quality Assessment Guidelines (SQAGs)

SQAGs are biological-effects based guidelines developed for FDEP to be used as

a tool when studying soil-associated contaminants in coastal environments. Data have

been collected by FDEP for over a decade and analyzed to establish these guidelines,

which identify ranges in concentrations of contaminants that have low to high

probabilities of causing adverse biological effects to aquatic organisms (Florida

Department of Environmental Protection, 2000).

An absolute determination of detrimental biological effects cannot be based solely

on the evaluation of SQAGs. These guidelines should be used in conjunction with other

available data, due to several limitations. Specifically, these guidelines represent

pollution potential only. Cause and effect relationships are not inferred when comparing

these guidelines to other chemical data. Another limitation is the issue of bioavailability.

Factors that can control metal sorption such as total organic carbon (TOC) are not

equated when deriving SQAG ranges. A third limitation is that the data used to develop

the guidelines were collected from across the country. How well these guidelines

represent all Florida soils is uncertain. In addition, these values were derived for coastal

water soils, not freshwater. However, with guidelines for freshwater systems currently

under development, the SQAGs for coastal environments have been indirectly applied in

past studies. While the use of SQAGs in contamination studies may have limitations,

their value as contaminant indicators is the first step in determining possible areas of

concern relating to soil quality.

To determine pollution potential from the SQAGs, ranges have been established

which divide each contaminant of interest in to three different categories (Table 2). The

first, and lowest pollution potential range is considered the no effects level. At these









concentrations the contaminants rarely or never are associated with adverse biological

effects to aquatic organisms. The second range is classified as the threshold effects level

(TEL). It is at this minimal concentration that contaminants frequently cause adverse

biological effects. Last of all, we have the range of highest pollution potential, classified

as the probable effects level (PEL). When concentrations of pollutants exceed the

minimum value of this range there are usually or always adverse biological effects on the

aquatic community exposed.




Table 2 Soil quality assessment guidelines for heavy metals in study. Values established
in the Florida Department of Environmental Protection Soil Quality Assessment
Guidelines for Coastal Sediments
Contaminant No Effects Level Threshole Effect Level Probable Effect Level
(mg/kg) (mg/kg) (mg/kg)
Cadmium 0 0.675 0.676 4.20 > 4.20
Chromium 0 52.2 52.3 159.9 > 159.9
Copper 0 18.6 18.7- 107.9 > 107.9
Lead 0-30.1 30.2- 111.9 > 111.9
Nickel 0 15.8 15.9- 42.7 > 42.7
Zinc 0 123.9 124- 270.9 > 270.9


Baseline Concentrations for Trace Metals in Florida Soils

When comparing contaminant levels of trace metals to actual field values, it is

important to distinguish between natural-occurring metal concentrations and those that

may be attributed to anthropogenic sources. Years of contaminant inputs to soil makes

establishing true background concentrations difficult (Chen et al., 1999). Work

conducted by Chen et al. (1999) evaluated the use of baseline concentrations to estimate

natural levels of trace metals in Florida surface soils.









It was determined that the use of baseline concentrations better represented the

variation in trace metal concentrations, than did using the observed ranges. Log

transformations of the values minimized the few high concentrations, which could distort

the overall range (Chen et al., 1999). These baseline concentrations were used for

comparison in this study (Table 3).




Table 3. Baseline concentration for Florida Surface Soils (Chen et al., 1999)
Metal Calculated Baseline Concentration (mg/kg)
Cd 0-0.33
Cr 0.89- 80.7
Cu 0.22 21.0
Ni 1.70-48.5
Pb 0.69 42.0
Zn 0.89-29.6


Metals

Stormwater has been shown to contain a number of different contaminants,

dependent upon the watershed collection area, that may pose health and environmental

threats to exposed communities. Metal concentrations in stormwater have been identified

through studies to be the most commonly detected contaminants at many locations.

Metal concentrations at sites may be a mix of natural occurrence and anthropogenic

inputs. The process of mass loading metals on soils already containing natural trace

metal concentrations could lead to the accumulation of potentially toxic levels of

contamination. In addition, the potential for human, animal, and aquatic organism uptake

and storage of metals internally could create long-term health concerns. To assess

concerns relating to heavy metal exposure, each contaminant should be evaluated on its

potential to affect human and environmental health. The following information on metal









toxicity was obtained through the Agency for Toxic Substances and Disease Registry

(ATSDR) website, located at www.atsdr.cdc.gov (ATSDR, 2001).

Cadmium (Cd)

Cd is an element that can be found naturally in the earth's crust or used in a

variety of applications, including manufacturing of batteries, paint pigments, metal

coatings, and plastics. Additionally, the burning of fossil fuels can contribute to the

presence of Cd in the environment.

Cd can enter natural systems through deposition from air emissions, as well as

through leaching or washing of contaminated sites. Sediment contamination from Cd

occurs through sorption to organic matter, and through co-precipitation with iron, Al, and

Mn-oxides. It binds strongly to soil particles, not breaking down in the environment, but

rather changing forms.

Exposure to Cd occurs mainly through inhalation of contaminated air, ingestion of

contaminated food sources or through contaminated water supplies. The bio-availability

of Cd in sediments is dependent upon pH, redox potential, water hardness, and the

presence of other completing agents. Studies have shown that animals exposed to high

doses of Cd experienced lung disease and stomach disorders. Cd ability to remain in the

body for a very long time allows for levels to build up, even if exposure concentrations

are low. Aquatic organisms exposed to Cd have shown various effects, including acute

mortality, reduced growth, and inhibited reproduction. It is unclear whether human

exposure to Cd will result in similar diseases when exposed to equal levels as in animal

studies. Exposure to Cd through dermal contact has no known effect in either humans or

animals.









Recommendations to protect public health have been made by several

governmental agencies. The United States Environmental Protection Agency (USEPA)

has established limits for Cd in drinking water set at 0.005 parts per million (mg/L). The

United States Food and Drug Administration (USFDA) allows up to 15 parts per million

(ppm) in food colorings, while the Occupational Safety and Health Administration limits

workplace air to 100 ug/m3 as Cd fumes, and 200 ug/L as dust particulate (ATSDR,

2001). Additional guidance concentrations have been derived for use with the SQAGs,

and SCTLs. SQAGs have established a TEL of 0.68 mg/kg, and a PEL of 4.2 mg/kg.

The SCTLs for exposure limits are set at 75 mg/kg for residential exposures, and 1300

mg/kg for commercial exposures.

Chromium (Cr)

Similar to Cd, Cr is an element that can be found occurring naturally in the

environment, as Cr(III), or as a byproduct from various industrial processes as Cr(0), or

Cr(VI). Processes involving the use of Cr include steel production, paint and dye

production, leather tanning and wood preservation.

Cr enters the environment through deposition from air emissions and leaching at

contaminated sites, mainly in the Cr(III) and Cr(VI) forms. Once introduced to a natural

system its fate depends upon the form at which it enters. In aquatic systems Cr(VI) tends

to be very soluble, not readily sorbed to particulate matter. However, as anaerobic

conditions prevail, Cr(VI) reduces to Cr(III), a state which can strongly sorb onto organic

particulates.

Exposure to Cr contamination occurs through inhalation, ingestion, or dermal

contact. Inhalation of high levels of Cr(VI) has been shown to cause nasal irritations

such as nosebleeds or ulcers. Ingestion of similar levels can cause stomach, liver or









kidney damage, which may result in death. Unlike Cd, dermal exposure to high levels of

Cr(VI) may result into skin ulcers. Individuals with severe allergies may experience

swelling and redness to exposed areas. Studies have shown Cr(VI) compounds can

increase the risk of lung cancer, and the several health organizations have labeled Cr(VI)

in various forms as a human carcinogen. Additional adverse effects to biological

communities include death and decreased growth, particular by vegetative species. Fish

do not tend to be as sensitive as humans to Cr contamination (ATSDR, 2001),

Federal regulations have been established by the EPA and OSHA to protect public

health from exposure to high levels of Cr. EPA recommends Cr concentrations in water

not to exceed 0.1 mg/L. In addition to drinking water standards, SQAGs and SCTLs

have been derived for contamination and remediation assessments. Under the SQAGs, a

TEL of 52.3 mg/kg and a PEL of 160 mg/kg have been established for aquatic biota

protection. The SCTLs for residential and commercial exposures are 210 mg/kg, and 420

mg/kg, respectively.

Copper (Cu)

Cu is a natural occurring metallic element in crustal rocks and minerals, released

during weathering processes. Anthropogenic sources of Cu include agricultural

fungicides, pesticides, sewage treatment effluent, wood preserving, and fallout from

industrial sources and coal burning.

Cu can enter natural systems through weathering of minerals, release in air

emissions, and through direct exposure as in soil or water treatment devices. Inhalation,

ingestion and dermal contact are the main pathways for Cu exposures to many organisms.

While Cu is considered an essential micronutrient, exposure to elevated levels in the air

can cause irritations to the nose and mouth. Ingestion of high levels of Cu can lead to









kidney and liver damage as well as stomach disorders. Dermal exposure to elevated Cu

levels can result in an allergic reaction or rash in sensitive individuals. There is no

indication that Cu exposures can lead to cancer in either humans or animals. However,

Cu contamination of aquatic systems may be associated with acute and chronic toxicity in

biotic organisms (ASTDR, 2001).

Human health concerns from Cu contamination have led to the establishment of

federal guidelines regulating consumption and workplace exposures. Drinking water

standards have been set at 1.3 mg/L. In addition to EPA and OSHA regulations,

protective levels have been derived under the SQAGs and the SCTLs. The SQAGs have

established a TEL of 18.7 mg/kg, and a PEL of 108 mg/kg. Residential exposure

guidelines established for SCTLs has been set at 110 mg/kg, while commercial exposure

limits are 76,000 mg/kg.

Lead (Pb)

Pb is a metallic element that is found in virtually all parts of our environment.

While it can be naturally occurring, anthropogenic sources contribute heavily to its

presence. These sources include the burning of fossil fuels, mining, and the

manufacturing of batteries, metal products, and ammunition. The use of Pb in many

items such as paints and gasoline has been greatly reduced due to health concerns.

Pb can enter natural systems through deposition with air particulates or by

leaching or washing of contaminated surfaces. Once Pb comes into contact with

sediments, its movement is dependent upon the type of Pb compound and soil

characteristics. Pb(II) tends to be the most stable ionic species, and can be found bound to

Fe and Mn-hydroxides in addition to clay and organic matter. Oxidized sediments tend









to bind closely with Pb, with its release and mobility increasing under reducing

conditions. The majority of exposures to Pb occur through ingestion or inhalation.

In humans, Pb exposures to high levels have been shown to affect the organs of

the body and the central nervous system. Blood disorders and male reproductive

problems may also occur. Aquatic organisms also exhibit toxic affects from Pb. Plants

tend to be less sensitive to exposures than fish or invertebrates. While studies involving

animals indicate the possibility of Pb to be a carcinogen, there is no evidence to suggest

carcinogenic effects in humans.

Federal agencies have set regulations to control Pb exposures through ingestion

and workplace incidences. Drinking water standards for Pb are set at 0.015 mg/L.

Additional recommendations have been made regarding Pb screening programs for

children who live in areas determined to be high risk zones (ATSDR, 2001). The SQAGs

have derived a TEL of 30.2 mg/kg, and a PEL of 112 mg/kg. SCTLs set exposure limits

at 400 mg/kg for residential classifications, and 920 mg/kg for commercial sites.

Nickel (Ni)

Ni is an element found abundantly in the earth's crust, primarily combined with

oxygen and sulfur. Ore deposits often contain Ni with Fe or Cu. While Ni is used in a

variety of manufacturing and industrial industries, the major anthropogenic sources

include, fossil fuel combustion, batteries, Ni ore mining, smelting and refining activities,

and electroplating (FDEP, 2000).

Anthropogenic sources of Ni may enter environmental systems as small deposits

in air particles, or through the washing and leaching of surfaces containing Ni. As

anthropogenic sources are introduced to sediments they become bound as Fe or Mn-

oxides or they sorb with organic matter. Release of Ni from sediments may decrease









under anaerobic conditions as they form insoluble complexes with sulfides. Human and

animal exposures to Ni can be through inhalation, ingestion or dermal contact.

Ni is considered a required element for maintaining good health, but, exposures to

high levels can cause adverse health effects. The most severe exposures for humans and

animals in terms of health related concerns appear to be through dermal contact and

inhalation. Allergic reactions from contact with Ni, in the form of skin rashes, are the

most common types of health effect seen. Workplace exposure to air particles containing

Ni compounds have been linked to lung as nasal cancers. In terms of adverse effects on

aquatic organisms, increased mortality rates, decreased growth and avoidance reactions

have been observed.

With certain Ni compounds determined to be carcinogenic, federal agencies have

established recommendations regarding ingestion on water containing these compounds

(ATSDR, 2001). In addition to drinking water standards of 0.04 mg/L, occupational

exposure levels have also been established to reduce concerns from inhalation. For the

protection of aquatic organisms the SQAGs have derived a TEL of 15.9 g/L, and a PEL

of 42.8 g/L. SCTLs have been determined to be 110 ug/L for residential considerations,

and 28,000 ug/L at commercial sites.

Zinc (Zn)

Zn is an abundant element, found in air, soil, and water. As a crustal element it is

present commonly as a sulfide, carbonate, or silicate ore. Zn has a number of different

production uses, including dry cell batteries, rust preventatives, and as a mixture with

other metals to form alloys.

Release of Zn into the environment can occur through natural processes.

Anthropogenic inputs from air deposition and leaching also contribute to its presence.









Much of the Zn entering the environment stays bound to soil with Fe and Mn-oxides, clay

minerals and organic matter. Adsorption rates of Zn have been determined to be pH

dependent, showing a decrease in aquatic systems with pHs below 6. Sorption to organic

matter in fine grained sediments is controlled by reducing conditions, which form

insoluble sulfides (FDEP, 2000).

Health concerns over exposure to Zn arise from ingesting contaminated food or

water supplies, or from breathing aerosolized Zn particles near manufacturing plants. Zn

is an essential element to the diet of humans, requiring an appropriate balance to be

effective. Since our bodies require Zn, low inputs to our systems can be just as harmful

as exposures to high levels. Ingestion of high levels of Zn may lead to short-term

stomach and blood disorders and possibly pancreas damage. Inhalation of Zn at high

concentrations may cause lung irritations and body temperature fluctuations on a short-

term basis. Long-term effects for Zn inhalation have not been determined. Affects on

aquatic organisms appear to be minor as they can experience a wide range of sensitivity

to Zn exposure. Zn is currently not listed as a possible carcinogen (ATSDR, 2001).

Federal agencies have established recommendations for human exposures to Zn

contamination through drinking water of 0.005 mg/L, and workplace exposure

guidelines. To protect aquatic organisms, the SQAGs have recommended a TEL of 124

mg/kg, and a PEL of 271 mg/kg. SCTLs have been established at 23,000 mg/kg for

residential sites, and at 560,000mg/kg for commercial cleanup designations.


Metal Attenuation in Stormwater retention Basin Sediments

Stormwater runoff has been shown to contain various contaminants dependent

upon the input source. Metals, being one variety of stormwater contaminant, can









accumulate in stormwater soils depending upon soils characteristics, such as pH,

percentage of organic carbon, percentage of Fe and Mn oxides and existing metal

concentrations. As vegetation within stormwater systems decays, organic matter can

accumulate. Igloria, et al.. (1997), studied the effects of natural organic matter (NOM) as

a source for attenuation of metals in stormwater, and as a facilitator of metal transport

within stormwater basins. Their conclusions were that the addition of NOM did not

enhance metals transport, but in fact, the high affinity of the NOM to the soil in

combination with the metals attraction to the NOM decreased the metals mobility

(Igloria, et al., 1997). Another study evaluated Cu and Cd distribution in forested soils

and determined that organic matter or Fe and Mn-oxides were responsible for

immobilizing Cu, and that Cd attenuation was also dependent upon metal-oxide

relationships (Keller and Vedy, 1994).

Similar results for metal deposition in relation to organic matter were reported by

Walker and Hurl (2002), and Goulet and Pick (2001). Metal distribution has been shown

dependent upon not only its association with organic matter, but with stormwater basin

design, such as depth and planted vegetation. Stormwater basins with shallow water

column depths may allow for a larger distribution pattern due to water turbulence stirring

and moving sediments (Goulet and Pick, 2001). In addition, vegetation can act as a plug,

slowing the velocity of stormwater inflow and reducing the effects from wind on shallow

surfaces in retention basins.

Metal uptake within stormwater retention basin soils may play a large part in the

spatial distribution at which contamination is detected. In vegetative wetlands, Cd, Cu,

and Zn concentrations have been measured the highest in 0 5 cm samples, while Pb









concentration was shown to increase to a depth of 55 cm (Cheng et al., 2002). A study

conducted by Kao et al., (2001) compared contaminant removal rates from influent for

both vegetative and unplanted soils surfaces. In a wetland setting both Pb and Zn

concentrations decreased by 95% and 92% respectively, from stormwater inflow to water

quality exiting the system. Although lower, the unplanted treatment basin showed an

effluent contaminant removal rate of 32% for Pb, and 40% for Zn (Kao et al., 2001).

Typically redox potential may play a part in the partitioning of metals with

stormwater basin soils. In soils where the redox potential is greater than 100 mV, most

metals present within pore water will either precipitate as metal-oxides or adsorp to

organic matter. As redox potential decreases to between 100 mV and -100 mV,

reduction of metal-oxide can result in the release of dissolved metal back to solution. If

enough organic matter is present the metals may still adsorb, otherwise they may be

transported with the water column through sedimentation. Below -100 mV, metal-soil

relationships are developed strictly through reactions with monosulfides and organic

matter adsorption (Goulet and Pick, 2001).

Clearly studies have been completed which indicate relationships between soil

characteristics and their roles in metal attenuation. Sediments within the stormwater

retention basin at the NATL are no different that many of these study sites in terms of

organic content, contaminant input sources and other variables. Ignoring the possibility

of metal accumulation to potentially hazardous levels within sediments in the SEEP or

any other stormwater retention basin could be a dangerous oversight.
















OBJECTIVES

In the past, urban stormwater retention basins served the purpose of collecting and

treating stormwater runoff before it infiltrated or discharged into a water resource.

Basins were not created nor intended to be used for recreational purposes or to be

considered quality habitats for wildlife or aquatic organisms. Access to these areas may

have been limited through locked gates or minimized by undesirable site conditions, such

as dry retention ponds. The situation is changing with the integration of wetlands into

stormwater basins emerging as a method of enhancing treatment to improve the quality of

discharge.

With the development of the stormwater basin at the NATL focused on increased

opportunities of study for students and faculty at UF, in addition to creating a diverse

habitat for wildlife, exposure to contaminants commonly found in urban stormwater

water runoff could occur through ingestion, inhalation, or dermal contact. Regulatory

considerations focus mainly on environmental protection through water quality

improvement, with little emphasis on soil quality.

The lack of regulatory guidance for stormwater soil contamination played an

important role in the development of the objectives for this study. Both the ability to

provide information that could be used in determining the direction of future stormwater

studies at the basin, and to specifically address contamination concerns related to the

usage of the basin as a research site and as a wildlife habitat, were desired outcomes.









Objective 1 -Evaluation of Current Soil Conditions for Future Studies

One anticipated study for the stormwater basin is to determine the efficiency and

effectiveness of the wetland design in pollutant removal from stormwater. Soils will play

an integral part in this process. No background levels of contamination or other soil

quality parameters exist for soils within the retention basin. By establishing these levels,

future studies can compare parameters similar to those that have been documented

through this research.


Objective 2 Comparison of Current Metal Concentrations in Basin Soils to Soil Target
Cleanup Levels

The University of Florida will continue to use the basin as a research site. With

the availability of contaminant exposure to students working in the area, current metal

concentrations will be compared to established SCTL concentrations. In doing so,

possible problematic areas can be identified and addressed accordingly. Additionally,

these values may be applied to evaluate potential contamination concerns

for wildlife.


Objective 3 Comparison of Current Metal Concentrations in Basin Soils to Soil Quality
Assessment Guidelines

As the basin ages, a diverse aquatic community is expected to thrive within the

wetland zones. The stability of this aquatic community relies upon its surrounding

environment. The SQAG's establish concentration ranges for contaminants to evaluate

the possible adverse health effects that these ranges may pose upon the aquatic

community. Areas of concern can be delineated and marked for further studies in

bioavailability and accumulation.






43


As previously stated, the objectives of this research were set to provide the

University of Florida with accurate information on existing soil quality in the NATL

stormwater retention basin. Information obtained through this research can be used in

determining the future direction in which the management and usage of the basin may

proceed.















MATERIALS AND METHODS


Site Description

The study site was the retention basin at the Natural Area Teaching Lab (NATL),

located on the campus of the University of Florida The NATL is located at the

southwestern corner of the University campus (Figure 7) This location affords

individuals an excellent opportunity to conduct field studies of multiple ecosystems The

outdoor research facility consists of a total of 18 62 ha Lying within this property are

three upland communities, hammock, upland pine, and old field succession, as well as

thriving wetland communities surrounding both a small sinkhole and the ecologically

enhanced retention basin (Figure 8)


FiglUNIVERSITY OF
j', -| -.M I-- -4,
A.=







I *I -

FL o e B tl.- A TctngL



Figure 7 Location of Retention Basin at Natural Area Teaching Lab





































Fire8 Layout ofNatialAreaTeachingLab


Nine departments in four colleges have dedicatedstudies ivolvmng areas of the

NATL (WetladsClub, 2001) Included also istheWetlandsClubwhchbas

coordinated withthe NATL Advisory Committee and he UF Physical Plat to develop

whatheas now come tobe known asthe StormwaterEcologcal Enhancemet Prqect

(SEEP) The ideafor theSEEP wasto create a multi-stage welnds desinednot only to

treatand, dispose ofurbanstormwaterrmoff, but to create desirable condlihonsthat

wouldattract and sltavariouswildlife secies Additional benefits delved fromthe

development ofthe SEEP prq ectinclude

1) Anincreaseinthe overall aeshetics oftheNATL










2) Expanding research opportunities to individuals interested in wetlands study

3) Affording students as well as the public the chance to study wetland systems

in a formal class setting or, by independent viewing.

The stormwater basin is a 1.21-hectare retention pond, which collects runoff from

a number of sources existing within the 40-hectare watershed that it serves. Natural

runoff from the surrounding undeveloped areas becomes mixed with runoff from the

watershed's impervious surfaces that is transported through an underground network of

piping (Figure 9).


Figure 9. Photograph of stormwater runoff collection area covered with debris.


Of the approximately 41% impervious surfaces existing within the basin, the most

intensive and probable source for pollutant transport comes from parking surfaces,


1. ^.i _






47


particularly an 1100-space commuter lot to the north, and parking for the


Entomology/Nematology building to the east


(Figure 10)


Figure 10 Natural areas and parking surfaces draining to the retention basin A)
Transition area from old field succession to upland pine B) Southerly view of commuter
parking lot and garage C) Entrance to Entomology & Nematology building located to
the east of the stormwater retention basin



The basin was onginally constructed in 1988 with permitted storage capacity

designed to accept and dispose of 18,855 m3 of stormwater runoff through infiltration and

evaporation The collection period based on a 100-year flood event based over a 24-hour


- L"A


SEEP Watershed

Pervious Surfaces

pavement sidewalks rooftops surface water
Impervious Surfaces









span. Urban development within the watershed required that the basin be redesigned in

1990 to handle an additional 12,221 m3 of runoff, bringing its total capacity to 31,076 min3.

Design of the basin was traditional in its approach. The lack of surface water

discharge negated the use of a detention system to improve water quality of the disposed

stormwater, allowing for stormwater retention to be the driving force in design. With

retention basins that do not discharge to surface waters, there is greater emphasis on

storage of runoff as opposed to enhanced stormwater treatment. This particular design

was typical of a standard retention basin, dependent upon evaporation and percolation to

dispose of stormwater on-site. Uniform slopes lined the basin to the north, south, and

east, while the west side was contoured to a natural depressional area. Stormwater

entered the system through four major collection sites and was guided to the flat center of

the basin for disposal (Figure 11).

With the concept of the SEEP, basin design became more ecologically enhanced

by the addition of berms in the northern and southeastern portion of the retention basin

and by creating deep water infiltration ponds to the south (Figure 12). Functionality of

the basin shifted from a pure retention type system to a system incorporating retention

theory, using both vegetation and increased water detention periods in conjunction with

on-site disposal.














A) B)













D



















Figure 11 Original design of stormwater retention basin before enhancement project
began A) Stormwater inlet collecting discharge from commuter lot and garage B)
Stormwater inlet collecting runoff from Entomology & Nematology building C)
Stormwater inlet collecting runoff from behind and adjacent to Florida Museum of
Natural History, and the Performing Arts Center D) Stormwater inlet collecting runoff
from unpaved parking lot and grass swales behind and to the west of the Entomology and
Nematology building

















































Figure 12 Diagram of the retention basin post enhancement that occurred in 1998
Berms added to the north and southeast sections of the basin increase and direct
stormwater flow The two infiltration ponds to the south allow for increased settling of
stormwater particulate matter and evaporation









Samphng Locations

When developing a soil sample scheme for the stormwater management

system, the first step was to separate the basin into individual cells Each cell could be

evaluated for contamination and comparative values would exist between each region

The existing configuration of the stormwater basin dictated a division of three cells for

evaluation (Figure 13)


Figure 13 Breakdown of the sample cells inside the stormwater retention basin









Cell one represented the forebay, extending from the north end of the basin to the

northern berm, including three of the four stormwater inflow pipes. Cell two

encompassed the remaining stormwater inflow pipe located at the southeastern comer of

the basin and extended to the southernmost section of the berm bordering cell one. Cell

three, the final section of the stormwater management system, consisted of the two deep-

water ponds.

Cell one was further separated into three sections for evaluation. The first

section, located in the northwestern comer of the stormwater management system,

contained two of the three stormwater inflow pipes, which drained the entire impervious

surface of the major parking area. Flow patterns were established through observed

channeling from the inflow areas, and five locations, Al through A5, were sampled

(Figure 14). The emphasis on these sites was to determine soil quality from the

stormwater inflows to the center of the forebay. All the sites chosen in this area consisted

of soils that had been left undisturbed during re-contouring.

The second section of cell one consisted of a single point just west of the

stormwater inlet pipe located in the northeastern part of the basin. This point, labeled A6

(Figure 14), represented undisturbed basin soils to the east of center in the forebay.

Flows in this area were made up of sheet flow from a two-lane road and parking lot

runoff from the front section of the Entomolgy/Nematology building.

The third section of this cell was the center of the forebay. The majority of this

area, represented by sites A7 through A12 (Figure 14), was scraped during the 1998 re-

contouring. However, site A9, located in the northern part of this section appeared not to

have been disturbed based on the surface texture, and from a visual inspection of the site









after the re-contouring. Sample site locations within this section represented contaminant

and suspended particle movement from the stormwater inflows through the forebay,

exiting from the weir into cell two.

In cell two, five sample locations were chosen for evaluation. Sites Bl, B2, & B3

(Figure 14) were located south of the weir in an area that had been scraped in 1998. This

represented water flow movement as it entered into cell two, dispersing either south,

southeast, or southwest. A major decision for choosing these points is that soil quality

can be compared between their locations and site A7 to evaluate the efficiency of the

forebay in pollutant removal. Site B4 was situated in the direct flow path coming from

the remaining stormwater inlet pipe to the southeast of the basin. Water flow in this area

was channeled towards the deep-water infiltration ponds by the southern berm and

several small elevated mounds. The soil surface in this area had again been scraped in

1998. The remaining site in cell two, B5, was located in the western portion of the basin.

This area had not been re-contoured in 1998 and was the only section consisting of

original undisturbed soil in cell two.

In cell three, two locations were chosen for evaluation (Figure 14). Site C1 was

located in the center of the first deep-water pond, while C2 was centered in the

southernmost deep-water pond. Due to the need to restructure the infiltration ponds when

creating the SEEP, the entire area within this cell had been re-contoured. An additional

sample, Dl, was taken from outside the stormwater management system to act as a

control site. This site was located to the west of the system, directly behind the

Performing Arts Center.





54













A4 4 A7 A7

Dl
3





B5








N



FFa t


Figure 14 Lo a mpno stale sites in fite stormwater retention basin










Secondary consideration was given to sample site locations for the evaluation of

soils left m place from the origmal construction of the stormwater management system,


as compared to soils from the recently re-contoured areas (Figure 15)


Eight ofthe 19


sites within the basin were located in areas left undisturbed, allowing for evaluation and

the creation of baseline datafor undisturbed and scraped areas (Table 4)


Figure 15


Sample site locations for the stormwater management system Areas outlined


in red contain soils left undisturbed dunng the 1998 re-contouring of the system









Information gathered from the 20 sample sites selected has been used to set

baseline data for future studies at this site. From the locations selected, a good

representation of the extent of contamination within the basin already can be seen, and

some assumptions made based on current soil quality conditions.


Table 4. Sample site

Cell Ste


status for each cell evaluated.

Location Scraped /Undistuted
A 1 U ndisturbed
A 2 U ndisturbed
A 3 U ndisturbed
A 4 U ndisturbed
A 5 U ndisturbed
A 6 U ndisturbed
A 7 S craped
A 8 S craped
A 9 U ndisturbed
A 10 Scraped
A 11 S craped
A12 Scraped


S craped
S craped
S craped
S craped
U ndisturbed


S craped
S craped









Field Procedures

Samples were taken using the guidelines set forth in the Comprehensive Quality

Assurance Plan of the Southwest Florida Water Management District, (1993). All soil

samples were collected with shovels and stainless steel equipment. Soils surfaces, that

came into contact with steel equipment, were removed through the use of non-metallic

spatulas. All loose debris not affixed with the soil was remove before sampling. Coring

devices and spatulas were cleaned with distilled water after each core sample was

completed. Once obtained, samples were stored on ice until transfer was complete to the

University of Florida Environmental Pedology lab. Composite samples of 4 to 7 cores

within an area of 0.25m for each site were analyzed at depths of 0-5cm and 5- 10cm.

In all, 20 sites were selected, bringing the total number of analyzed soil samples

to 40. Of the 20 sites, 19 (Al A12, B1 B5, C1 C2) were located inside the

stormwater management system, with one (Dl) being taken outside the system to

represent background data.


Laboratory Procedures

All samples were prepared by first air drying and then running through a 2.0 mm

sieve before ball milling to achieve a homogeneous mixture. Samples were analyzed for

heavy metals, organic carbon content, organic matter content, pH, and particle-size

distribution (Table 5).










Table 5. Sediment analysis and methods used in study
SOIL ANALYSIS METHOD
Metals (Cd, Cr, Cu, Ni, Pb, Zn) Digestion EPA 3050
Analysis Inductively Coupled Plasma (ICP)

Organic Carbon Content Walkey-Black Method
(Soil Survey Laboratory Methods Manual, 1996)

Soil Organic Matter Loss On Ignition (Broadbent, 1953)

Particle Size Distribution Pipette Method (Day, 1965)

Soil pH Soil Survey Laboratory Methods Manual (1996)



Metal Analysis

The heavy metals selected for analysis were chosen based on their rank as the

most common determined in urban stormwater runoff during a 1995 DEP study of

contamination in 87 stormwater management facilities (Livingston, et al., 1995). The

specific metals analyzed were Cd, Cr, Cu, Pb, Ni, and Zn.

A one-gram sample digestion of dried soil was completed at the UF Soil

Environmental Pedology Lab using EPA Method 3050, as directed under the standard

operating procedure guidelines set by UF Professor, Dr. Lena Ma. Sample solutions were

then placed in standardized containers and sent to the Analytical Research Laboratory,

located on the University of Florida campus for analysis by an Inductively Coupled

Plasma (ICP) analyzer. Minimum detection limits for all metals was 0.01 mg/kg, with

the exception of Cr, which was 0.04 mg/kg.

Organic Carbon Content

The organic carbon analysis was completed using the Walkley-Black method.

Samples which exceeded the acceptable range for percent organic carbon using this

method were run again by lowering the samples size to 0.125g or 0.025g, making the









appropriate calculations to obtained percent organic carbon. While the Walkley-Black

method works well on soils with less than 6% organic matter, the loss on ignition method

better suits soils with organic matter contents greater than 6% (Agvise Laboratories,

2002).

Organic Matter Content

To determine organic matter content, the loss on ignition method, as described by

Broadbent (1965), was used. Three grams of soil were placed into 20 ml crucibles and

brought to a temperature of 1050C for 2 hours. Samples were then weighed to

+0.01grams, then brought to a temperature of 5000C for a period of eight hours. After

being allowed to cool in a moisture-free environment using a desiccator, the samples

were again weighed and recorded. To determine the percent organic matter the following

equation was used:

% Organic Matter =(Sample Weight 105C Sample Weight 5000C x 100) /Sample

Weight 1050C

Particle-Size Distribution

Particle-size distribution was determined on the samples using the pipette method

as described by Day (1965). Since the clay content of these samples was unknown, a

sample weight of 25.Og (+/- 0.1g) was used. Values obtained were compared with a soil

texture classification triangle to determine the appropriate textural class.

pH Analysis

Stormwater retention basin soils were analyzed for pH using the method

described in the Soil Survey Laboratory Methods Manual (1996). Twenty five grams of

soils was analyzed using both water and potassium chloride.









Statistical Methods

Statistical analysis was done using the Number Cruncher Statistical

System (NCSS) data analysis software program. Linear regression analysis was

conducted to examine relationships for all dependent variables (metals) to the

independent variables, pH, organic carbon, organic matter, and percent clay content.


Estimating Metal Loading Rates

Analytical data presented in this thesis has indicted that metal concentrations at

certain locations within the stormwater retention basin exceed several indirect guidelines

for soil clean-up and quality assessments. At what point soils within this and similar

basins reach potentially toxic levels is unclear, without regulatory requirements for

periodic soil monitoring. If certain information is known about a particular basin, then

estimates can be made as to a particular concentration of contaminant loading.

For this study, water quality data was not collected, ruling out the option for site

specific loading rates. There are, however, ways to determine rough estimates of metal

loading based on computer-generated programs. One such program is the Long-Term

Hydrological Impact Analysis (L-THIA) GIS based model. This analysis uses

established hydrologic data, based on a long-term average in combination with defined

land use and soil classes to establish stormwater runoff rates. When site specific data

relating to stormwater metal concentrations is not used with this model, non-point source

pollutant averages established by the Texas Natural Resource Conservation Commission

(TNRCC) becomes the default.

Arial photography was used to create a land-use layer for the SEEP watershed.

The land use and the soils layer will be combined with 20-years of local rainfall data to






61


generate curve numbers and runoff volumes on a one-meter cell grid. L-THIA then

averages these volumes and calculates the average annual runoff volume for each of the

one-meter cells in the drainage basin. These volumes are summarized for each land use

class and combined with runoff coefficients for each metal based on those land use

classes. The total average annual loading of each metal on the SEEP can then be

calculated. These loading rates can be used to place in context the concentrations of

metals found in SEEP soils.
















RESULTS

The initial objective of this study was to analyze current soil conditions within the

SEEP located at the NATL. Since limited soil data exists for this area, evaluating

parameters such as organic carbon content, organic matter content, pH, and particle-size

distribution may lay the foundation for establishing baseline standards for future studies

at this site.

Urban development of adjacent land within the watershed has required

improvements and upgrades to the stormwater basin, altering soils from their original

pedogenic stages. Soil dating back to the initial construction of the basin indicate soils

not representative of what can be identified today.

Just as important as the altering of soils within the basin for stormwater runoff

collection, are the effects that outside inputs carried in stormwater can have on the

environmental quality of the system. Pollutants, such as heavy metals in stormwater

runoff, may interact differently in soil depending upon soil characteristics.

While it is not uncommon to detect various heavy metals in soils through either

natural deposition or anthropogenic processes, concentrations should be maintained at

levels acceptable to the environment. Metal concentrations of the soils inside the

stormwater retention basin were compared to baseline concentrations for Florida surface

soils established by Chen et al, (1999). Additionally, indirect comparisons were made

with the screening levels referenced by the SQAGs, and the SCTLs.









Organic Matter Content

Soils within the stormwater basin were analyzed for percent organic matter at

both 0-5cm and 5-10cm depths (Figure 16). The results indicated the highest organic

matter values in cell 1, within the heavily vegetated northwestern comer of the wetland

basin, sites Al through A5. At these locations, percent organic matter ranged from 2.7%

to 22% in the upper 5cm samples with an average of 11.3%. The 5-10cm samples ranged

between 1.7% and 21%, averaging 7.7%. The remaining seven sites in cell one ranged

from 2% to 7%, averaging 4.5% in the upper samples, and from 1% to 5.3%, averaging

3.9% in the 5-10cm samples.

In cell 2, percent organic matter ranged from 5.1% to 7.1% in the 0-5cm samples

with an average of 6.0% within the cell. The 5-10cm samples ranged from 5.1% to 7%,

averaging 5.7%. Four of the five sites evaluated in this cell had been previously scraped

during the 1998 re-contouring of the stormwater basin. Excavation at these sites had

removed what little sandy deposits that may have been present, exposing the argillic

horizon to the surface.

Samples taken in cell 3 were limited to two locations, C1 and C2, both scraped

during 1998 construction and redesign of the basin. Percent organic carbon in the 0-5cm

samples was 11% and 8% respectively, and 7% and 8.3% in the 5-10cm samples. The

slightly higher averages for this cell in relationship to cell 2 may be explained by a thin 2

cm biomat that had formed in the dry pond region.

Additional analysis for organic matter content was completed on the control

sample located outside the basin, site Dl. At this location, the upper limit sample had a

concentration of 3.6% organic matter, and the lower sample depth was 2.6%. A complete

list of organic matter contents for all of the sample locations are shown in appendix C-4.















Cell 1 Cell 2 Cell 3























Al A2 A3 A4 A5 A6 A7 A8 A9 Al Al Al BI B2 B3 B4 B5 C1 C2
0 1 2


* 0-5cm
* 5-10cm


Site Location


Figure 16. Percent organic matter in soils within the stormwater retention basin.










Organic Carbon Content

Quantitative limitations of the Walkley-Black method created a data gap for

several sites where organic carbon content was above the upper limits of detection (6%).

Specifically sites A2, A3, & A5 could not be evaluated. For the remainder of the basin,

percent organic carbon ranged from 0.11% to 4.19%, with highest values in cell 1. There

were five sites within cell 1 that had a percentage greater than 1%; site Al(0-5cm) 1.5%,

site A4(0-5cm) 2.3% and (5-10cm) 1.1%, site A6(0-5cm) 4. 1%, site A10(0-5cm) 3.5%,

and site Al l(0-5cm) 4.2%. There was only one other site where percent organic carbon

exceeded 1%, which was C1 (0-5cm) at 1.7%. At the control site, percent organic carbon

was calculated to be 0.78% in the in the 0-5cm sample, and 0.75% in the 5-10cm sample.

The higher than expected percentages of organic carbon determined to be present

in these soil samples, may indicate complete oxidation of organic material was not have

been achieved. Thus, values obtained for percent organic carbon may be considered

marginal quantitative data at best. A complete list of percent organic carbon results are in

appendix C-4.


Soil pH

Soil pH was analyzed in both water and potassium chloride for all the sample

sites. The results for water analysis and presented in this study (Figure 17). For this

analysis, four locations, including the northwestern comer of cell 1, the remainder of cell

1, cell 2, and cell 3, will be separated for discussion.

In the northwestern comer of cell 1, the pH ranged from 7.3 to 8.3 in the 0-5cm

samples. The 5-10cm samples had a pH range of 7.2 to 7.8. The pH values in this

section were higher than in any other part of the basin. A possible source of this pH






66


increase could be coming from limestone particulates that have been washed into the cell

from road runoff. In the remainder of cell 1, the 0-5cm samples had a pH range from 5.9

to 7.2. The 5-10 cm samples had a pH range of 5.5 to 6.8.

In cell 2, the 0-5cm samples had apH from 5.1 to 7.1. The 5-10cm samples had a

pH range of 5.1 to 7.0. The 2 sites in cell 3 had a pH range of 6.7 to 7.0 in the 0-5cm

sample, and a range of 5.3 to 6.8 in the 5-10cm sample. The pH for the control sample

was 6.1 in the 0-5cm depth, and 6.2 in the 5-10cm sample. The data for pH can be found

in appendix C-4.













Cell 1 (Center & NE Section) Cell 2 Cell 3













Al A2 A3 A4 A5 A6 A7 A8 A9 Al Al Al B1 B2 B3 B4 B5 C1 C2
0 1 2
Site Locations


0-5cm Sample 0 5-10 cm Samples


Figure 17. Soil pH at locations within the stormwater retention basin.










Particle-Size Distribution

Percent sand, silt, and clay were determined and compared to the soil textural

triangle to establish a major texture class for each sample. Also, field texturing was

conducted at each site using the "feel" method described in Brady (1999). Values are

reported at all locations with the exception of sites A4 and B4, where laboratory error

gave invalid results. The following breakdown of cells describes the soil textures as

determined by the particle-size distribution.

For the purpose of study, soil analysis in the stormwater basin was separated into

four areas: the northwest comer of cell 1, the center and eastern portion of cell 1, all of

cell 2, and all of cell 3. The major textural classes in the northwestern portion of cell 1,

sites Al through A5, were determined to be sandy and loamy materials. Analysis

indicated that 4 of the 5 surface samples in this location were classified as sands, with the

remaining site, A3, texture a loamy sand. The subsurface samples ranged from sand to a

loam texture. All of these site locations were in areas where no recent scrapping had

occurred.

In the remaining locations of cell 1, A6 through A12, surface textures varied from

loamy sand to sandy clay loam. The sandier locations were represented by sites A6 and

A9, which were not scraped during the re-contouring of the SEEP. Loamy sand extended

into the 5-10cm depth at each of these locations. The remaining sites within cell 1 had

been scrapped down to the argillic horizon, leaving a sandy clay loam present at the

surface, extending through the 5-10cm sample.

The majority of sites sampled within cell 2 were of similar texture class as those

identified in the center of cell 1. The surfaces for sites B1 through B4 had been removed









during redesign of the basin, exposing finer textured sandy clay loam material. Site B5 in

the westerly region of this cell, however, had remained untouched, leaving sandy to

loamy sand textured material.

Cell 3 had been entirely reworked as part of the plan to enlarge and deepen the

ponds to the south of the retention basin. Excavation in this area completely removed

any of the sandier textured soils down to the argillic horizon. Both sites evaluated in cell

3 fell within the textural triangle as either sandy clay loam or sandy clay. The control site

soils were classified as sands in both the 0-5cm sample and the 5-10cm sample. Data for

the particle-size distribution in the basin soils is listed in appendix C-1.


Metals: Cadmium

Cd vs. Baseline Concentration Levels

Cd was detected at 5 of 19 soil sample locations within the stormwater retention

basin. Concentrations in the 0-5cm samples ranged from 0-2.5 mg/kg and were identical

in the 5-10cm sample depth. Detection above the upper limit of the baseline

concentration range occurred in 4 of the 0-5cm samples and in 2 of the 5-10cm samples

(Figure 18). Three of the sites where detection occurred were within the initial treatment

zone, cell 1. The two remaining sites were split between cell 2 and cell 3. The sites

where Cd was present were above the baseline concentration range of 0-0.33 mg/kg as

established for Florida surface soils (Chen et al., 1999). Cd was not detected in the

control site sample located outside the retention basin.

Cd Concentrations Compared With Various Screening Levels

Of the 5 sites where Cd was detected, concentrations at three locations, all in cell

1, were above the TEL of 0.676 mg/kg established by the SQAGs (Figure 19). There






70


were no exceedences for PELs of 4.20 mg/kg, or the SCTLs residential and commercial

based values of 75 mg/kg and 1300 mg/kg respectively (Figure 20).



































0-0.33 mg/kg Baseline Concentration


-t (N mf i mO ) N co O M 0 H N H- N rN i
f^~~ ~~~ H^ H^f ^f ^ ^f m m m m
<~p~ <~ < < < PaP aP


Ln H cN
M U U


Site L ocatbns


Figure 18. Cadmium concentrations in the stormwater basin soils. The baseline concentration range for cadmium in
soils is represented by the red shaded region..


Florida surface


* 0-5cm
* 5-10cr























































Figure 19 Location of sites where cadmium concentrations were detected above
threshold effects levels (TELs) derived by the soil quality assessment guidelines Sites














Cell 2 Cell 3


H- CN ro n i m CO C
[< < [< < [< < [< < [<


O r-H N c N ro mf 1 m CJN
SH-i -i M M M M u U


S ie L ocatbns


Figure 20. Comparison of cadmium concentrations to screening criteria throughout the entire basin. These concentrations were
evaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects level (TEL) derived by
the soil quality assessment guidelines (SQAG's).


* 0-5cm
* 5-10cn










Metals: Chromium (Cr)

Cr vs. Baseline Concentration Levels

Cr was detected at all 19 sites within the stormwater retention basin with

concentrations ranging from 21.0 -262.5 mg/kg in the 0-5cm samples and from 12.0-180

mg/kg in the 5-10cm samples. When compared to baseline concentration data there were

4 sites that exceeded the established range of 0.89-80.7 mg/kg (Figure 21). These sites

were located in cell 1, to the northwest comer of the retention basin. The highest

concentrations of Cr in these areas were detected in the 0-5cm samples, with baseline

exceedences in the 5-10cm samples occurring at only 2 of the 4 locations. When

comparing elevations of Cr in the control sample, they fell within established baseline

concentrations at both the 0-5cm sample (20.5 mg/kg), and the 5-10cm sample (23.5

mg/kg).

Cr Concentrations Compared With Various Screening Levels

Cr concentrations were compared to the derived protection levels established

under the SQAGs. Exceedences of TELs set at 52.3 mg/kg occurred at 4 sites within cell

1 to the northwest comer of the retention basin (Figure 22). Levels of concern extended

into the 5-10cm depths at 2 of the locations. Additionally, concentrations of Cr were

high enough at these same 4 sites to exceed the PEL of 160 mg/kg, although, only one

site showed a PEL exceedence at a 5-10cm depth.

When comparing the data to the SCTL residential and commercial toxicity values,

2 sites contained Cr concentrations above the SCTL residential value of 210 mg/kg. The

concentration of Cr above SCTLs did not extend to the 5-10 cm depth. There were no Cr

concentrations above the SCTL commercial-based values of 420 mg/kg. Concentration






75


of Cr in the 5-10cm samples exceeded levels in the 0-5cm samples at 6 of the 19

locations within the basin (Figure 23).






























Baseline Concentration Range


H- C ro i m [N co O -t C'N


S ite L ocatbns


H c' rn PQ m H N'J
m- mN m m m- u- uN


Figure 21. Chromium concentrations in the stormwater retention basin soils. The baseline concentration range for
Florida surface soils is represented by the red shaded region


chromium in


0.89 80.7 mg/kg


* 0-5cm
* 5-10cm














A B C

0-0 0

l 0 O11AS0 2. 0 0 AS
A5 Al A5 A12 A5 A12
A4 A7 A4 A7 A4 A7
o o 0 0 0 0
DI B DIl E2 Dl l
O O 0 3 0 0 0
BA Bi Al Bl










N N N



20m 2m 20m


Figure 22 Location of sites where chromium was detected above contaminant screening levels (A) Sites exceeding threshold effects
levels (TEL's) as established by the soil quality assessment gmuidelnes (SQAG's) are shaded in yellow (B) Sites exceeding probable
effects levels (PEL's) as established by the SQAG's are shaded in red (C) Sites exceeding soil cleanup target levels (SCTL's)
established in Chapter 62-777, Florida Administrative Code Sites shaded in orange represent residential toxicity value exceedences
(RTV's)















300 -


* 0-5cm
* 5-10cm


HT (N C mn y 0m M 0
H


H c'N
H <


H CN rn 1 m CH N
M M M M M U U


S ite L ocatbns


Figure 23. Comparison of chromium concentrations to screening criteria throughout the entire basin. These concentrations were
evaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects levels (TEL's) and
probable effects levels (PEL's) established by the soil quality assessment guidelines. Additionally, concentrations exceeded soil
cleanup target levels (SCTL's) for residential values (RTV's). Concentrations of chromium in the 5-10cm depth samples exceeded
the concentrations in the 0-5cm sample depths at 5 of the 19 sample site locations.










Metals: Copper (Cu)

Cu Vs. Baseline Concentration Levels

Cu concentrations were detected at all 19 sites within the stormwater retention

basin. Levels ranged from 5.5-235 mg/kg in the 0-5cm sample depths and from 3.0-102

mg/kg in the 5-10cm samples. Seven sites exceeded the upper limit of the baseline

concentration range (Figure 24). Similar to both Cd and Cr, exceedences were observed

in the northwest comer of cell 1. Elevated levels were also documented at three other

locations within cell 1, including the highest concentration at the northeastern stormwater

inlet, and at one location in cell 3. In 18 of the 19 sites the 0-5cm sample depths

contained a higher concentration of Cu, with the one exception being site A2. This was

also the only location where the 5-10cm sample depth exceeded the baseline range upper

limit. Cu concentration in the control sample was at 3.0 mg/kg at both depths, which falls

within the established baseline range.

Cu Concentrations Compared With Various Screening Levels

The SQAGs have a derived TEL for copper of 18.7 mg/kg. Cu concentrations in

the soils of the retention basin exceeded TELs at 8 sites. Seven of these sites were

located in cell 1, with the remaining site located in cell 3. Two of the sites had levels of

Cu in concentrations higher than the PEL of 108 mg/kg. Each of these two locations

were in direct flow from the stormwater inlets to the northwest and northeast areas of cell

1.

The SCTLs have established exposure protection limits from Cu for residential

and commercial applications of 110 mg/kg, and 76,000 mg/kg, respectively. Residential

exposure concentrations were exceeded at the two sites in direct flow from the inlets in






80


cell (Figure 25). Cu was not detected at levels exceeding the commercial based values

established by the SCTLs.

As indicated with the comparison to the baseline concentration range,

concentrations of Cu in the 5-10cm depth samples tended to be lower than in the upper

sample. Of the 7 sites where Cu was detected above screening levels, exceedences in the

5-10cm sample depths occurred at only one site (Figure 26). This was consistent with the

entire basin.



















200


150 I


100


50


0.22 21.9 mg/kg Baseline Concentration Range


* 0-5cm
* 5-10cm


H cN r m w 0 m 0 H CN H O rH (N mn H 'N
Sg g g g r g '-g '-H '-m Mm mm U U


Site L ocatbns


Figure 24. Copper concentrations in the stormwater retention basin soils. The baseline concentration range for copper in Florida
surface soils is represented by the red shaded region

















All
14 Oa
0
DI '!3 cI
Dl (


B 5
D 1 : II ~ '









N '

30m
--3m-


11
PA 0
-4 %




0
DI
S : =i









N


30m '


: o
9.^4 -
A010

Dl (I


E5







N
\3m


Figure 25. Location of sites where copper was detected above contaminant screening levels. (A) Sites exceeding threshold effects
levels (TEL's) as established by the soil quality assessment guidelines (SQAG's) are shaded in yellow. (B) Sites exceeding probable
effects levels (PEL's) as established by the SQAG's are shaded in red. (C) Sites exceeding soil cleanup target levels (SCTL's)
established in Chapter 62-777, Florida Administrative Code. Sites shaded in orange represent residential toxicity value exceedences
(RTV's).





































-H Cq m Lin m O N O 00
<


H CJ
H H
T9 T9


250


* 0-5cm
* 5-l0cm


Site L ocatbns


Figure 26. Comparison of copper concentrations to screening criteria throughout the entire basin. These concentrations were
evaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects levels (TEL's) and
probable effects levels (PEL's) established by the soil quality assessment guidelines. Additionally, concentrations exceeded soil
cleanup target levels (SCTL's) for residential values (RTV's). Concentrations of copper in the 5-10cm depth samples exceeded the
concentrations in the 0-5cm sample depths at only one site within the basin.


Cell 2 Cell 3








110mg/kg SCTLRV


108 mg/kg PEL







I- CJ m. f t m -- C'L
Cm m Cm m Cm u u










Metals: Lead (Pb)

Pb Vs. Baseline Concentration Levels

Concentrations of Pb were detected in soils at all 19 sites within the retention

basin. Concentrations in the surface samples ranged from 7.0-61.0 mg/kg, and from 0.5-

64.5 mg/kg in the 5-10cm depth samples. When compared the baseline concentrations, 2

sites exceeded the upper limits of the concentration range established at 0.69-42.0 mg/kg.

Both locations were in cell 1 at the northwestern comer of the basin. Exceedences

occurred in the upper samples at both locations and in the 5-10cm sample at one site

(Figure 27). Pb concentration in the control samples was at 4.5mg/kg and 5.0 mg/kg in

the 0-5cm sample and the 5-10cm sample respectively.

Pb Concentrations Compared With Various Screening Levels

The concentrations of Pb in soils were compared to screening levels established in

the SQAGs and the SCTLs. The SQAGs have derived a protection value of 30.2 mg/kg

as a TEL for Pb in sediments. Basin soils exceeded this value at 4 locations, 3 of these

sites being located in the northwestern comer of cell 1, and one site on the northern end

of cell 3 (Figure 28). Exceedences occurred at the 0-5cm sample depth in 2 of the 3

locations in cell 1, and in the lone location in cell 3. Pb concentrations in the 5-10cm

samples exceeded TELs at 2 locations in cell 1 only. When evaluating the entire basin,

Pb concentrations in the 5-10cm samples exceeded the upper 0-5cm samples at 5 of 19

sites, or 26% (Figure 29). Pb did not exceed the PEL of 111.9 mg/kg or SCTLs for

residential (400 mg/kg) and commercial (920 mg/kg) exposures.






















0.69 42.0 mg/kg Baseline Concentration Range


* 0-5cm
* 5-10cm


H N r 0 H O N H N r ocat nsN


S is L ocatbns


Figure 27. Lead concentrations in the stormwater retention basin soils. The baseline concentration range for lead in Florida surface
soils is represented by the red shaded region


- 60 -










0
o 20-
r0




0 -























































Figure 28 Location of sites where lead concentrations were detected above threshold
effects levels (TEL's) derived by the soil quality assessment guidelines Sites above
TEL' s are shaded in yellow














/U


60 Cell 2 Cell 3


50


40
0-5an

30 0 5-10an


o 20


10


0
H (N Lr i 0m 0w 0 H N( H (N rn i m H (H N


S ite L ocatbns

Figure 29. Comparison of lead concentrations to screening criteria throughout the entire basin. These concentrations were evaluated
at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects level (TEL) derived by the soil
quality assessment guidelines. Concentrations of lead in the 5-10cm depth samples exceeded the concentrations in the 0-5cm sample
depths at 5 of the 19 sites within the stormwater basin.