Insights into the Mechanisms of Iron Reductive Dissolution in Vadose Zone Soils and Implications for Landfill Activities

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Material Information

Title:
Insights into the Mechanisms of Iron Reductive Dissolution in Vadose Zone Soils and Implications for Landfill Activities Predicting the Potential for Groundwater Pollution
Physical Description:
1 online resource (153 p.)
Language:
english
Creator:
Oppong-Anane, Akua Bonsu
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Environmental Engineering Sciences
Committee Chair:
BONZONGO,JEAN-CLAUDE J
Committee Co-Chair:
DELFINO,JOSEPH J
Committee Members:
TOWNSEND,TIMOTHY G
HARRIS,WILLIE G,JR

Subjects

Subjects / Keywords:
dissolution -- iron -- landfill -- oxides -- reductive
Environmental Engineering Sciences -- Dissertations, Academic -- UF
Genre:
Environmental Engineering Sciences thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Anomalously high iron (Fe) concentrations have beenmeasured in groundwater samples collected from monitoring wells downstream ofseveral landfill units in Florida. Based on monitoring data, vadose zone soilsand aquifer sediments impacted by landfills could be sources of Fe thatpollutes the groundwater, and not landfilled wastes. Therefore, the objectivesof this study were to investigate the reductive dissolution of soil-Fe as afunction of biotic and abiotic processes; and to lay the groundwork for thedevelopment of a geochemical solubility model for Fe. Soil samples were collected from different locations in NorthFlorida, using a sampling strategy that included samples with a gradient in thedegree of Fe-mineral crystallization. After characterization, soil samples wereused in biotic (using bacteria from an anaerobic digester) and abiotic (usingsulfide as electron donor) Fe-reductive dissolution batch studies. Fe(II) wasreleased from all soils in concentrations that exceeded the secondary drinkingwater limit of 0.3 mg/L, when treated with bacteria and organic carbon (OC) or withsulfide but under abiotic conditions. Microbial respiration of OC in soils appearsto be a major pathway and could lead to Fe-reductive dissolution in Fe-richsoils that interact with OC-rich waters or leachates. The rates of Fe-reductivedissolution were positively correlated with soil Fe content when glucose wasused as the OC source, while no relationship was obvious when landfill leachatewas used as OC. Sulfide driven Fe-reductive dissolution was positivelycorrelated with soil-Fe content. However, despite the initial high release ofFe(II) into the aqueous phase in soil spiked with sulfide, temporal trends ofFe-reductive dissolution rates suggest that this pathway may not be assignificant as the biotic process due likely to the precipitation of solid FeSspecies. Finally, batchstudies were conducted using hematite, an Fe-oxide mineral, to investigate theeffects of pH, OC and ionic strength on Fe-reductive dissolution rates. Obtaineddata were used to develop a geochemical solubility model for soil-Fe; which wasthen validated using soil samples. However, an efficient fine tuning and validationof the model was not fully accomplished as more experimental and field data arestill needed.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Akua Bonsu Oppong-Anane.
Thesis:
Thesis (Ph.D.)--University of Florida, 2014.
Local:
Adviser: BONZONGO,JEAN-CLAUDE J.
Local:
Co-adviser: DELFINO,JOSEPH J.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2015-05-31

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2014
System ID:
UFE0046156:00001