Expanding agricultural and industrial production have significantly improved the socioeconomic status of many Kentuckians. Associated with some of these activities, however, are impeded soil and water quality that impact the health and quality of life for many citizens and the environment. The essence of Biogeochemistry is to gain an understanding of biological and chemical processes that govern the fate of contaminants in the environment, and to use this knowledge to develop solutions to environmental problems.

Once toxic contaminants are detected, we can take steps to remediate these systems. For example, we now know that if natural microbial populations are provided appropriate growing conditions, they will detoxify the pollutants by degrading them or binding them with soil organic matter. Once relationships between environmental conditions and detoxification processes are understood, it will be possible to manipulate them to enhance removal of toxic chemicals in these environments.

About 90% of Kentucky's wetlands have been lost since settlement in the 1700's. With these losses, we have lost several important wetland functions including wildlife habitat, water purification, and flood control. In accordance with the goal of "No Net Loss" of wetlands by the US administration, we are assigned the task of saving remaining wetlands and constructing replacement wetlands that fulfill these functions. In Kentucky, new wetland impacts are required to be mitigated at a minimum ratio of two acres restored for each one acre lost. One question facing Kentuckians is, "How do we know whether constructed/restored wetlands are adequately performing the functions of original, undisturbed wetlands?" We are in the process of evaluating water purification processes and microbial diversity in disturbed and undisturbed wetlands to determine whether easily measurable indicators can be used to assess the success of wetland restoration.

My research focuses on the biological and chemical fate pathways of toxic organic chemicals (chlorinated aromatic compounds) and other contaminants (phosphorus) in soils, water and wetlands. Several projects are in progress that address these issues: development of genetically-engineered microbial detection systems for chlorinated aromatics in soils and water, evaluate the microbial ecology and degradation/humification of chlorinated aromatics in wetland and upland soils, determine the capacity of Kentucky soils and other sorbents to sequester animal manure-derived phosphorus and bacteria in the landscape, and evaluate the use of biogeochemical indicators as tools to assess the health of natural and constructed/restored wetlands.

Highly chlorinated organic compounds are only partially degraded under either anaerobic or aerobic conditions, generating several toxic by products. This project investigates whether sequential anaerobic and aerobic microbial processes in the plant rhizosphere and soil-water interface will enhance the degradation of chlorinated organic chemicals in flooded soils. Results will be valuable for the design of treatment systems for soils contaminated with this class of compounds.

Polychlorinated Biphenyls (PCBs) are among the most common and toxic substances at Superfund sites, and contamination has resulted in several fish consumption advisories in Kentucky rivers and streams. This study investigates ways to promote biodegradation and binding-attachment of PCBs to soil organic matter through stimulation of key microbial communities, so that contaminants no longer pose a threat to humans or the environment.

Over 50% of US wetlands have been lost or impacted by urban and agricultural activities, hence there is interest in protecting and restoring these ecosystems. This study investigates whether genomic diversity and metabolic processes of aerobic and anaerobic bacteria are sensitive bioindicators of ecosystem impact and recovery.

We are testing the ability of different sorbents to sequester important domestic waste and agricultural contaminants phosphorus and bacteria from water. Suitable sorbents are to be installed in agronomic settings as part of integrated grass filter strip-permeable reactive barrier systems with the goal of preventing water pollution from runoff and leaching from fertilizer and manure-amended soils.

In this project, we are investigating nutrient cycling processes, biogeochemical indicators, and the HGM system in a series of laboratory and in situ studies with soil and litter obtained from low-gradient, riverine wetlands, with the goal of linking actual wetland processes to biogeochemical indicators and HGM variables. Results will ultimately be useful by providing diagnostic tools to assess the water quality improvement function of created and restored wetland ecosystems. The study will also generate data required for development of N and P nutrient quality standards for wetlands as required by EPA in the year 2003.

The Soil & Water Biogeochemistry and Environmental Microbial Genomics and Ecology Laboratories in the Department of Agronomy at the University of Kentucky are well equipped to conduct the studies described above, including the following equipment and instrumentation:

Biogeochemistry (PLS/NRC 450G)

This three credit hour lecture course focuses on quantitative descriptions of the chemical, physical and biological processes that determine the behavior of chemicals in the environment. Emphasis will be placed on soil processes, and their influence on soil, air, and water quality. The practical objectives of the course will be predictions of chemical fate and recommendations of management practices to ameliorate pollutants in the environment.

1. Provide overview of basic chemical and physical properties of soil, water, and atmosphere, and classification of pollutants.

2. Explain the dominant transformations, partitioning, and transport processes governing the fate of pollutants and significance on environmental quality.

3. Describe strategies to remediate environmental pollutants in the soil-water environment.

1985 B.S. University of Central Florida, Limnology, minor Chemistry, Department of Arts and Sciences

1999-pres Assistant Professor, University of Kentucky, Agronomy Department

1995-1998 Graduate Research Assistant, University of Florida

1986-1999 Senior Biological Scientist, University of Florida

1999 Excellence for Graduate Research, Institute of Food and Agricultural Sciences, University of Florida

1998 Excellence in Graduate Research, Soil and Water Science, University of Florida

1996 Sam Polston Outstanding Graduate Student Scholarship, University of Florida

1995 National Research Initiative Competitive Grants Award, USDA

1980 Gymnastics Scholarship, Jacksonville State University, AL

Dhritiman Ghosh (Post doctoral fellow)

Terry Meade (M.S., now at USDA National Soil Tilth Lab, IA)

Martin Vandiviere (Senior research technician and M.S. student)

Stephanie Wehr (M.S., now at US EPA, OH)

Luo Wensui (Ph.D candidate)

Shifen Xu (Post doctoral fellow)