Environmental Health - Toxic Substances Hydrology Program
The editors of Environmental Science and Technology have identified their journal's 10 most highly cited research papers. USGS scientists, currently with the Toxic Substances Hydrology (Toxics) Program, authored three of these historic papers.
The paper documented for the first time the role that organic ligands play in the adsorption of trace metals. Their work showed that organic compounds, such as humic substances or fulvic acids, adsorbed onto surfaces can also form metal-organic complexes, thus acting as an additional way to adsorb trace metals onto surfaces. James Davis, a USGS scientist, has gone on to study the fate and transport of dissolved trace metals in ground water. Davis and his colleagues have conducted some of the most chemically complex natural-gradient tracer tests in the world at the Toxics Program's Cape Cod Research Site.
This paper documented a reliable method for isolating, concentrating, and purifying dissolved organic matter in water samples. Understanding the nature of dissolved organic matter is an important step in studying the fate of metals and pesticides in the environment. Thurman, a USGS scientist and active researcher in the Toxics Program, has continued to develop important methods throughout his career with the USGS. Thurman and his colleagues have developed a variety of analytical methods to measure the concentration of the environmental metabolites of pesticides in water samples. In many cases, metabolites of pesticides are detected more often than the parent compounds. These methods formed the basis of the Toxics Program's studies on the fate and occurrence of agricultural chemicals in the Upper Midwest (Corn Belt) and the Southern United States (cotton production areas). Thurman is based in Lawrence, Kansas, were he runs an organic geochemistry research laboratory.
Scientists have correlated a contaminant's ability to bioconcentrate in fish with a measure of its solubility in an organic solvent, such as octanol, and its solubility in water known as the octanol-water partition coefficient. This publication filled a big gap in finding reliable octanol-water partition coefficients for common contaminants, such as DDT and other chlorinated compounds. Chiou and his colleagues showed that the solubility of an organic substance in water is intrinsically related to the compound's tendency to partition into organic substances, such as octanol or fish fat. They demonstrated that in the absence of reliable octanol-water partition coefficients, the much more readably available data on water solubility can be used to estimate either the compound's octanol-water partition coefficient or the compound's bioconcentration potential. Chiou is now an active scientist in the USGS's National Research Program where his Toxics Program research focuses on the partition and adsorption of persistent organic compounds and their uptake by soils, sediments, and plants.
Betts, Kellyn, Erickson, Britt, and Petkewich, Rachel, 2001, High-impact environmental research: Environmental Science and Technology, v. 35, no. 23, p, 488A-494A.
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