Trace Organic Contaminants, Including Toxaphene and Trifluralin, in Cotton Field Soils from Georgia and South Carolina, USA

Abstract

Residues of organic contaminants—including toxaphene, DDT, trifluralin, hexachlorocyclohexanes, polychlorinated biphenyls, polycyclic aromatic hydrocarbons (PAHs) and nonylphenol—were measured in 32 cotton field soils collected from South Carolina and Georgia in 1999. Toxaphene, trifluralin, DDT and PAHs were the major contaminants found in these soils. The maximum concentration of toxaphene measured was 2,500 ng/g dry weight. Trifluralin was detected in all the soils at concentrations ranging from 1 to 548 ng/g dry weight. Pesticide residues were not proportional to soil organic carbon content, indicating that their concentrations were a reflection of application history and dissipation rates rather than air–soil equilibrium. Soil extracts were also subjected to in vitro bioassays to assess dioxinlike, estrogenic, and androgenic/glucocorticoid potencies. Relatively more polar fractions of the soils elicited estrogenic and androgenic/glucocorticoid activities, but the magnitude of response was much less than those found in coastal marine sediments from industrialized locations.