University of Delaware Environmental Soil Chemistry Members In The News


Cooperative Extension

University of Delaware

College of Agricultural Sciences



Plant and Soil Sciences
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January 1995

UD Graudate Fellows Tackle Changes To Agriculture, Environment

An exciting part of graduate school for fellows in the department of plant and soil sciences at the University of Delawrae is knowing that they have an opportunity to work toward solving some real-world problems. "The College of Agricultural Sciences Fellowships that were an outgrowth of our college's strategic plan have enabled us to attract some first-rate graduate students," says Dr. Donald Sparks, chair of the department. "Our department has been most fortunate in having three students--Amy Brennan, Peter Vadas and Sharon Keeler--named to this prestigious fellowship." Amy Brennan is a graduate fellow who earned her bachelor's in environmental soil science from the department in 1993. She is now working on her doctorate in soil chemistry and environmental engineering under the direction of Sparks. As a part of Sparks research team, she is studying how time affects the fate and transport of Cesium-137 in soils. "Cesium-137 is a radioactive waste from weapons testing, nuclear accidents such as Chernobyl, and liquid waste from nuclear fuel production," Brennan explains. "In some government-controlled weapons-testing areas, the soil is still contaminated from tests performed more than 20 years ago. To reclaim that soil for use, or in the language of soil scientists--to remediate it, is the practical application of my research."

Brennan's research is just a small part of the total research needed to make this vision a reality. She is looking at how cesium is attached to soil particles, and especially at the kinetics, or speed with which it binds chemically. "The main point of my research is to look at kinetics--time differences of 20 years vs. yesterday--and see how that affects the way cesium is released," she says. "Perhaps efforts to remediate soils in the past have failed because they have not taken into account the time factor." Brennan says there are differences in the desorption rates (the rate at which cesium leaves the inner layers of soil) of 20-year-old cesium-contaminated soils and cesium that has been in soil laboratories for only a matter of days or months. Perhaps this knowledge can be used to help remediate soil so that it is no longer environmentally harmful. Brennan is hopeful that processes can be found to remediate the soils. For example, another harmless chemical such as potassium that carries the same positive charge that cesium does could be applied heavily, and through sheer force of quantity replace the cesium in the soil. "The quick, 24-hour studies that were done in the past, did not take kinetics (movement over time) into account," she says. "Therefore, remediation efforts haven't been very successful. With my research, I hope to define the different release rates over time." After graduating, Brennan hopes to work either as an industrial consultant, or with a government agency such as the EPA.

Another graduate fellow in the department, Peter Vadas, is a master's student who plans to graduate in June. His work in the area of soil management/chemistry will culminate in a thesis focused on the water quality in southern Delaware, especially the potential for phosphorus to travel from agricultural drainage ditches to sensitive surface waters. Vadas, who is working with Dr. Tom Sims, is investigating whether the combination of heavy poultry production and a high water table in southern Delaware makes the groundwater vulnerable to both nitrogen and phosphorus excesses. Sharon Keeler is a graduate fellow enrolled in the plant science doctoral program. Keeler, who has worked as a molecular biologist for the past eight years, plans to complete a doctorate and teach at the university level. She has been working with Dr. Sherry Kitto on a project involving heat tolerance of lima beans--an important vegetable crop in Delaware. Keeler is looking at the molecular basis for expression of heat-shock proteins that help all plants, including lima beans, survive heat stress.

by Claire McCabe


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