From the Chair...
Globally, there is great concern on new contaminants entering our
water bodies. The US Geological Survey (USGS) broadly defines these
emerging contaminants as naturally occurring or synthetic chemicals or
microorganisms that are not monitored in the environment. However,
these contaminants can potentially affect the health of natural systems
and human health. One of the key thrust areas of the Soil and Water
Science Department (SWSD) is on remediation of contaminated soils,
aquifers, and water as related to ecosystem soil and water quality and
public health. Select faculty in Gainesville and those located at the
Indian River Research and Education Center (IRREC) and Gulf Coast
Research and Education Center conduct research on a range of organic
contaminants and pathogens. State-of-the-art instrumentation is
available both in Gainesville and IRREC for use in this research. The
department is committed to strengthening the organic contaminants
programs to address current and future needs of our clientele, while
advancing the science in this area. In this newsletter we present a few
examples of research conducted in our department on fate and
transport of organic contaminants and pathogens in a range of
"We wish you and your family a safe and happy holiday season"
From SWSD Faculty, Staff, and Students
M 09 P MI V "M I -PMPI,. 1. .
Emerging Contaminants of Concern
The public and scientific presses, the internet, and other forms of mass communication are awash with references
to "emerging contaminants of concern" (ECCs). What are these contaminants, their sources, the sources of concern,
and what is the Soil and Water Science Department doing about them?
Contaminants: The US Geological Survey (USGS) defines ECCs as "any synthetic or naturally occurring chemicals, or
any microbe, that is not commonly monitored in the environment, but that has the potential to enter the
environment and cause known or suspected adverse ecological and/or human effects." Given this broad definition
and modern analytical techniques, one can expect a wide diversity and huge number of substances to be labeled
ECCs. Various lists of, and names for, ECCs exist and include substances such as pathogens, antibiotic resistant
genes, prions, nanoparticles, pharmaceuticals and personal care products (PPCPs), endocrine disrupting chemicals
(EDCs), flame retardants (e.g., polybrominated diphenyl ethers PBDEs), hormones and anabolic steroids,
perfluorinated chemicals (PFCs), etc. The chemicals are also referred to as microconstituents and trace organic.
The potential list seems endless at times. Where have all of the substances come from, and is our civilization
doomed to irreparable damage?
Sources: Few, if any, ECCs are actually new. Releases
of ECCs are likely to have occurred for many years, Micro Constituents in Water: Where Do They Come From?
but may not have been detected (nor their potential
impact appreciated) until new detection (and impact Metalsand
assessment) methods were developed. Animal wastes, Plastics
which can include numerous veterinary antibiotics, Naura...yoccnn .
Hormones Paint Adhesives,
hormones, and various pathogens, have long been land .. industrial
applied. Human utilize an amazingly large array of Cons tunts l
personal care products (and pharmaceuticals) that Flm 2 1 B.
have been marketed for many decades. Animal Re"tarduantts plans
(including human) and plant hormone release to the Funf cide
environment is a natural part of life. ..*. d
Most PPCPs and human hormones (e.g., e.rsfm .mpo -'' Co"'bcs and
I r .. Naricolachnology
microconstituents) are delivered to wastewater m nhey comn Nanaml
treatment plants and are effectively removed from narmacautcal Drugs-
Prescription and Over-the.
influents by degradation and sorption to solids, or exit CounMter dielr4e
with effluent. A few chemicals are poorly removed, _
and some are actually produced (concentration
increases in effluent from precursors). Properly treated effluent becomes "reclaimed water" for a variety of
beneficial reuses (reducing freshwater demands). Digested solids from the plants often undergo additional
treatment to become biosolids that are recognized as valuable soil amendments. Nature itself promotes antibiotic
resistance among soil organisms as a survival mechanism against the numerous antibiotics produced by microbes as
competition weapons (and that we "harvest" to ward off disease.)
All kinds of chemicals (inorganic and organic), microbes, and other "insults" have been added to the environment
since time began. "Modern" civilizations add a dizzying array of new chemicals. Reclaimed water and biosolids,
animal manures, numerous agricultural chemicals can contain EECs and pose risks to human and environmental
health. History shows, however, that soils, aquatic systems, and humans are remarkably resilient, adaptive, and
assimilative if the insults are managed. Minimize direct pollution of water bodies with "strong" (undiluted, or
otherwise modified) wastes, apply wastes judiciously and appropriately (land application guidelines, best
management practices) so as to not exceed system assimilative capacity, practice good personal hygiene (e.g.,
washing hands and food thoroughly), and use common sense (moderation in all things). For more information,
contact George O'Connor at GAO@uft.edu.
Mycoremediation of DDT-Contaminated Soil
The Organic Contaminant Analytical Research Laboratory (OCARL) currently has two
toxic chemical degradation studies underway. The first one is the mycoremediation
of DDT-contaminated soil from North Shore Restoration Area (NSRA) at Lake Apopka,
near Orlando, FL. Natural attenuation rates of DDx (o,p'- and p,p'- isomers of DDT,
DDE, and DDD) are slow in these soils. The chemical stability of these compounds
may be a result of the low solubility combined with low activities of organisms
capable of metabolizing the compounds, and low biological availabilities of the
compounds. In situ bioremediation employing either indigenous or introduced
microorganisms may provide an effective method at low cost for remediating this
site. The general strategies to be investigated are mesocosms designed to stimulate
aerobic pathways for DDx metabolism via: 1)
biodegradation of contaminants by elimination of -
inhibiting factors to native fungal production of i ,.
extracellular enzymes; and 2) application of
mushroom agriculture waste or aqueous rinsates
from non-native and native fungi, and 3) addition
of substrates that enhance extracellular enzyme
(e.g. laccase and peroxidase) production in the
previously mentioned systems.
Numerous wood-rot fungi are capable of
degrading DDT, DDE, and DDD using non-specific
extracellular lignin-degrading enzymes. A wood-
rot fungi (Nectria sp.) isolated from NSRA muck
soil has been shown to degrade DDT and its
metabolites DDD and DDE. The use of filamentous
fungi isolated from contaminated soil offers
several advantages. In particular, the fungi are
already adapted to the contaminant levels found
Fruiting bodies (- 1 mm in size)
in the soil and the fungi have already been shown of Nectria sp. fungus found in an
to be competitive with the indigenous flora, aerobic mesocosm.
In addition to fungi from NSRA soil, other possibilities exist such as wood-rot fungi
and their excreted enzymes obtained from commercial mushroom farms' waste
material. One species of wood-rot fungi that is edible and produced commercially is
Pleurotus ostreatus, commonly called the "oyster mushroom", which may be a
candidate. P. ostreatrus, like the Nectria species, has been shown to biodegrade
DDT. Another edible and commercially produced wood-rot species is Agaricus
bisporus, commonly known as white button, Crimini, or Portobello mushroom.
Although A. bisporus has not been reported as capable of degrading DDT, DDE or
DDD, this species emits many of the same extracellular enzymes as P. ostreatus.
The spent growing substrate is a waste material that contains these enzymes and
spores from the mushroom. Land application of this waste material may lead to an
inexpensive method of bioremediation.This project is being conducted by OCARL
with guidance and funding from the St. Johns River Water Management District. For
more information, contact John Thomas at Thomas@ufl.edu.
Potential Environmental Toxicity of Nanomaterials
Nanoparticles and nanomaterials have found broad application and are in .
common use in many products, although most of us probably don't realize it.
Among the most common nanoparticles in use is nanosilver, used primarily for
its anti-bacterial properties. A common use for nanosilver is incorporation 0
into athletic clothing to suppress odors. The mode of action of nanosilver as
an antibacterial agent is not completely clear, although it appears to
destabilize cell membranes, resulting in cell death. Unintentional release of
nanosilver from industrial sites into the environment might potentially disrupt
a range of environmental processes mediated by resident soil bacteria, such U
that fundamental research is needed to investigate these potential impacts.
Dr. Hee-Sung Bae of the Soil Microbial Ecology Lab has been investigating the potential impacts of nanosilver on
anaerobic microbial communities in wetland soils, and has tentatively concluded that the potential for harm in these
environments is low. Zimrisha Allah also worked with Dr. Bae on this project as part of her undergraduate capstone
Nanosilver seems to be rapidly removed from contention by complexation with sulfide and perhaps other anions in
wetland soils. Dr. Bae found no measureable effects of relatively high levels of nanosilver (up to 100 mg silver per
gram of soil) on rates of methane or CO2 emissions from soil. Dr. Bae also tested the impacts of nanosilver on
methanogenic and fermentative bacteria in pure cultures, and again found no measureable response. We expected
inhibition of growth rates with high concentrations of the toxic nanosilver, but found none. In addition, more subtle
differences such as shifts in fermentation patterns in pure cultures of a fermentative bacterial strain were not
detected. The lack of inhibition of bacterial activities in soils is not too surprising, although reassuring. The lack of
inhibition of bacterial activities in pure cultures, however, is perplexing. Does this stuff not really work? Back to the
lab. For more information, contact Andy Ogram at: email@example.com
Carbonated Fumigant as Methyl Bromide Alternative
Methyl bromide is a pre-crop fumigant that destroys weeds, fungi,
nematodes, and the ozone layer. It was to be phased out by 2005, except
for critical use exemptions. Many alternatives have been put forth, but
none are as economically effective. The UF Organic Chemical Analytical
Research Laboratory (OCARL) will work in conjunction with University of
California Davis and USDA-ARS to demonstrate the viability of an
alternative approach. Pressurized carbonated fumigant, with and without
low permeability film, will be tested on different soil types in two states
(FL and CA) with shallow rooting and/or deep rooting crops using either
full field tarping or raised bed coverings. Multiple year field experiments
are planned to quantify fumigant dispersion patterns and demonstrate Tomato beds after fumigation and trans-
planting at UF Plant Science Education and
efficacy of various treatments. These include using different types Research Unit, Citra, FL
(virtually impermeable vs. new totally impermeable films) of plastic soil
covers in combination with various application rates of Telone products applied with carbon dioxide or nitrogen. The
UF OCARL group, along with the UF Entomology-Nematology Department and the USDA-ARS scientists, showed that a
polar fumigant (Telone or Telone C35) is dispersed faster with a polar gas (carbon dioxide) than a non-polar gas
(nitrogen). Carbonation in combination with low permeability films is expected to allow reduced application rates to
be viable. Efficacy will be compared to control using a full rate of methyl bromide application. The expected
outcome is an economically feasible alternative to methyl bromide that should reduce emissions, field buffer zones,
(Continued on page 5)
(Continued from page 4)
and the amount of fumigant needed per acre. The information generated will lead to training and adoption of new
techniques for county extension agents, future scientists and educators, and other stakeholders such as growers.
This project is being conducted with funding from USDA-NIFA (formerly known as the USDA-CSREES Methyl Bromide
Alternatives Program). For more information, contact John Thomas at Thomas@ufl.edu.
Of Chicks and Tomatoes: Salmonella's Coming of Age Short Story
Early this spring, one of the hens on my farm hatched a clutch of three
adorable chicks. Lacking foul-naming imagination, I called the yellow fuzz
balls Sat, Mona and Ella. The trio now has grown, developing into fairly
unattractive birds with decidedly un-adorable habits. Sat, Mona and Ella
wreak havoc in my yard by digging up mulch in flower beds, pecking at
tomatoes in the vegetable garden and climbing into the fig bush to snack
on the ripening fruit. As obnoxious as the three of them are, the damage
they cause pales in comparison to the devastation to the Florida tomato
industry caused by their name source: Salmonella enterica serovar St. Paul.
A multi-state outbreak of gastrointestinal illness a few years ago was
initially blamed on tomatoes from Florida, bringing the industry to the brink of extinction. Consumers were advised
not to buy tomatoes, whole-sale prices plummeted, farmers and processors were ridden by anxiety. The outbreak
couldn't have happened at the worst time, as we were right in the middle of the busiest harvest time. Eventually,
traceback investigations concluded that the source of the pathogen was imported hot peppers. Florida tomatoes
were exonerated, just in time for producers to recoup some of their financial losses.
Unfortunately, the reports of gastroenteritis outbreaks linked to fruits and vegetables are becoming more and
more common. Fresh fruits and vegetables, perhaps the most nutritious products at any supermarket, are now
viewed with ever-growing suspicion. Scientists, producers and consumers need to find out what events lead to the
produce-associated outbreaks of illness caused by Salmonella or pathogenic E. coli. With funding from Florida
Tomato Committee, Center for Produce Safety and Florida Department of Agriculture and Consumer Services, our
research group (in collaboration with researchers Drs. George Hochmuth, Jerry Bartz and Keith Schneider)
contributes to figuring out what causes the outbreaks and finding the most sensible pro-active solutions to ensure
microbiological safety of fresh fruits and vegetables.
So far it is clear that Salmonella and pathogenic E. coli can contaminate fruits and vegetables in the field, during
harvest, after harvest and in retail. Improperly composted animal manure used as a fertilizer, animal intrusion, or
contaminated irrigation water can all deposit pathogens in the field pre-harvest, and some eventually end up on
produce. During harvest and immediately post-harvest, the contamination may become amplified, especially when
workers' hygiene is not properly enforced. Supermarket surveys reveal that produce with visible signs of spoilage is
most likely to also contain Salmonella, and these decaying fruits and vegetables can further contaminate nearby
products. The results of these correlational studies are important because they allow producers and consumers to
rapidly adjust practices for minimizing contamination, farm-to-fork. We are testing whether different fertilization
and irrigation regimes can reduce the susceptibility of tomato fruits to contamination or transfer of the pathogens.
We are also screening the existing commercial and heirloom cultivars to test if any is more or less "susceptible" to
Salmonella. The results of these studies, we anticipate, will help develop comprehensive Best Agricultural
Practices for reducing contamination of fresh produce with human pathogens. For more information, contact Max
Teplitski at: firstname.lastname@example.org
Biosolids-borne Emerging Contaminants of Concern:
Occurrence, Fate, and Impacts
Modern science has produced innumerable products and medicines that improve our lives and provide many
conveniences that we take for granted. Of the thousands of anthropogenic organic chemicals entering wastewater
treatment plants every day, many (but not all) are effectively removed from waste influents (removal efficiencies
vary from 10 to 100%). Chemicals that are removed, but not degraded, accumulate in the solid phase (sewage
sludge) at varying concentrations (pg/kg to high mg/kg values). About half of the 7 million dry tons of solids
produced nationally are subsequently handled/processed to produce biosolids that are subsequently land-applied. To
what extent should we worry about environmental and human exposure to biosolids-borne emerging contaminants of
Numerous recent tabulations of ECC
concentrations in biosolids, including the 2009
EPA Targeted National Sewage Sludge Survey,
confirm wide variations in levels and
frequencies of detection of compounds like
pharmaceuticals, steroids, personal care
products, and flame retardants even in
domestic sewage sludges. Even more recent are
troubling reports of perfluroinated chemicals
accumulating in soils amended with biosolids
(apparently, with significant industrial
sources). Research interest in ECCs (aka. trace It'
organic, microconstituents) is strong, given ."Poll
numerous reports of certain contaminants in W* v
various environmental components, as well as era
adverse effects on aquatic organisms (even at avail
sub-part per billion concentrations) and soil amend
organisms (plants, earthworms, micro- nothing!
organisms), and possible unknown synergistic
effects of the multiple ECCs introduced simultaneously .
s all a bunch of hype!
itant du jour" syndrome
TPs are very efficient and will
ability in biosolids is so low,
e concentration in biosolids-
led soil is so low, that there's
g to worry about
The sky is falling!
* we're awash in evermore
* unknown toxicity,
Comparatively little research has focused the fate, transport, and potential impacts of ECCs, or groups of trace
organic, in biosolids-amended soils. Often computer model predictions substitute for laboratory measurements or
field confirmation of physical/chemical properties and estimates of human/environmental impacts (risk assessment).
Few of the models, however, have been validated, especially for biosolids-borne trace organic applied to soils.
Numerous data gaps exist that are pertinent and necessary for a scientifically sound risk assessment.
Our research program focuses on the risks of biosolids-borne ECCs, specifically, the antimicrobials triclosan (TCS)
and triclocarban (TCC) that occur in toothpastes, soaps, shampoos and many other personal care products We
identify ECC occurrences, sources and typical concentrations in biosolids, possible fates of the compounds in
biosolids-amended soils, and potential impacts of the chemicals on the environment and humans. Chemical
principles learned through decades of research with pesticides and priority pollutants (e.g., PCBs, dioxins, PAHs) are
likely applicable to trace organic. The research has shown that being biosolids-borne is likely to significantly alter
(reduce) contaminant bioavailability to plants and micro-organisms, environmental ability and, ultimately, risk to
the environment and humans. Much is known about biosolids-borne contaminants and extensive risk assessment has
been conducted on many biosolids-borne contaminants, but there is much yet to be learned. Such knowledge will be
critical to science-based regulations and to better inform attitudes toward risks to human and environmental health.
For more information, contact George A. O'Connor at: email@example.com
Attitudes Towards Emerging
Contaminants in Biosolids
Degradation Pathway of (-)-(a)-Pinene
The second degradation study is on the degradation pathway of (-)-(a)-
Pinene. The Organic Chemical Analytical Research Laboratory (OCARL) is
providing liquid chromatagraph-tandem mass spectrometry (LC-MS/MS)
technical training and support to Dr. Angela Lindner and Joonki Yoon of
the UF Environmental Engineering Sciences. (-)-(a)-pinene was chosen as
a typical model compound to study the biotransformation products of
monoterpenes, which are volatile non-methane organic compounds
generated by agricultural crops and forests. Globally, the biogenic
production of these compounds exceeds the anthroprogenic sources.
Monoterpenes inhibit ammonia monooxygenase an important enzyme TSQ Quantum
used in the nitrification process. Methane monooxygenase is very similar
in structure to ammonia monooxygenase and suffers from many of the same inhibitors.
Since methane monoxygenase plays an essential role in the activity of methanotrophs, an
investigation into the binding of monoterpene and its oxidation products to the active
sites of the enzyme was initiated. Elucidation of the oxidation mechanism of these
ubiquitous monoterpenes will further our understanding of methanotroph's role in the
global carbon cycle and in bioremediation efforts.
For more information, contact John Thomas at Thomas@ufl.edu.
Discovery Max LC-MS/MS
Natural Organic Matter Sorption onto a Range of
An investigation was conducted to understand the nature and mechanism of interactions of natural organic matter with
pyrogenic organic matter (biochar). The research goal was to understand how biochar soil amendments could increase
soil quality, C sequestration and possible retention of organic contaminants. The study examined the interaction of
catechol and humic acids with biochars pyrolyzed under a range of combustion conditions (250 to 650 oC) from
hardwood, softwood and grass biomass types, using batch sorption equilibrium experiments with catechol (a natural
OM monomer) and a humic acid mixture. The effects of biochar size (coarse vs. fine) and laboratory simulation of
biochar aging on the sorption affinity of biochar were also investigated.
Time-course sorption experiments indicated that 14 days were sufficient to establish sorption pseudo-equilibrium and
that among the three kinetics models tested, the diffusion model fit the data best. Maximum observed catechol
sorption increased with biochar combustion temperature, from 250 to 400 to 650 C, and from oak to grass. The results
of this study indicated strong correlation between catechol sorption affinity and micropore surface area and the
dominance of a surface coverage adsorption process for catechol-biochar interaction. In contrast, humic acid sorption
capacity was much lower and only within nanopores, indicating exclusion from the majority of biochar surfaces. The
results suggest that biochar sorption is controlled by surface morphology, chemistry, and sorbent molecular size. In
general, one can expect biochar added to soil to sequester large amounts of natural OM within its pore network. In
addition, these results are of practical value to those considering biochar as a tool for soil remediation for trace
organic contaminants. The research findings have been published in ESEtT, 2010.
The research was conducted by Gabriel Kasozi (former SWSD PhD student) and now a post-doctoral research associate
under Dr. Andrew Zimmerman (PI) from the Geological Sciences Dept., and other collaboration from Dr. Peter Nkedi-
Kizza (SWSD) and Dr. Bin Gao (Agricultural and Biological Engineering Dept.). For more information, contact
Faculty, Staff, and Students
Congratulations to the following for their accomplishments
Ben Skulnick Fellowship Luke Gommermann (Ellis)
Sam Polston Scholarship Davie Kadyampakeni
(Morgan & Kizza) & Debolina Chakraborty (Nair)
William Roberton Scholarhsip Lisa Gardner (Reddy)
& Jason Lessl (Ma)
UF GIS Day
Jongsung Kim (Grunwald)- First Place Poster
Soil Science Society of America
Jaya Das (Daroub t O'Connor) Third Place Poster
Xiong Xiong (Grunwald) Third Place Poster Paper
Alex Cheesman (Reddy & Turner) First Place
Society of Wetland Scientists
Lisa Gardner Honorable mention for best poster
American Society Agronomy
Manmeet Waria (O'Connor & Toor) First Place
Poster Paper -A-5 Division
Gustavo Vasques Nominated for Best Paper: Global
Workshop on Digital Soil Mapping Pedometrics, Rome,
Italy, May 24-26, 2010
Brent Myers received newly established 'Quantitative
Soil Science/Pedometrics Award" by the GIS
Laboratory of the SWSD
SWSD Superior Accomplishment Award Michael Sisk
Retirement Pete Straub 37 years of service ARL/
ESTL and Soil Chemistry program
Biodigestion, Sanitation, and Public Health in Developing Countries
Clean drinking water and proper sanitation techniques are vital to controlling the spread of disease. In developing
countries, improper waste management is a common problem. Inadequate sanitation leads to the propagation of
water borne diseases and promotes pathogen proliferation. These problems are exacerbated following natural
disasters like the recent earthquake in Haiti or the flooding in Pakistan, with poor sanitary conditions in emergency/
refugee camps leading to increased risk of disease epidemics and death due to dehydration and diarrhea.
Anaerobic digestion technology offers a wastewater treatment solution that is
inherently capable of significant pathogen reduction for a wide variety of organic
wastes, including human waste and animal manure. The microbial ecology within
an anaerobic digester effectively lowers pathogen levels. Competition with the
established digester microflora leads to pathogen decimation.
The Bioenergy and Sustainable Technology Laboratory is working on the design of a
digesting toilet as a pre-fabricated kit that can be quickly deployed for use in
natural disaster situations. Design parameters include easy deconstruction and
reconstruction, and use of off-the-shelf materials and basic tools. This will be an
important device not only for the victims of natural disasters, but also for first Biodigester under construction in
responders that find themselves lacking all basic services while trying to provide Pursat, Cambodia.
life saving attention to the victims.
In a related project with the UF Chapter of Engineers Without Borders, Ann Wilkie and students recently conducted
an assessment trip to Cambodia. Rural Cambodia experiences many of the same problems that other remote and
impoverished areas in the developing world face. The team worked with a locally-based NGO, Sustainable Cambodia,
to evaluate the water, sanitation, and energy needs of their partner rural villages. They found that while many
projects were being promoted for sanitation, clean water, and biogas, there was untapped potential for integrating
sanitation with digestion technology. If an effective latrine system were designed and implemented, it would help
reduce open defecation, which exposes water supplies to pathogens, and provide feedstock for anaerobic digestion.
Human waste, mixed and treated in the digester with cattle and pig manure, could provide biogas for cooking and a
safe organic biofertilizer to recycle valuable nutrients back to rice fields. Also, if clean water can be stored in the
wet season, families that cannot afford deep wells will not have to rely on distant, polluted water sources during
the dry season for drinking, cooking, and irrigation of small family gardens. The team is continuing to develop
sustainable solutions to address these problems and help to improve the quality of life in rural Cambodia. For more
information, visit Biodigesters for Developing Countries or contact Ann Wilkie at firstname.lastname@example.org.