Residual organochlorine pesticides in soils and fish from wetland restoration areas in central Florida, USA

Abstract

Four wetland restoration sites in the Emeralda Marsh Conservation Area located in central Florida, USA were flooded between 1992 and 1994. Florida Fish and Wildlife Conservation Commission stocked largemouth bass in the flooded areas from 1992 to 1996. In 1996, organochlorine pesticides (OCPs) were measured in flooded soils and in black crappie, brown bullhead catfish, and largemouth bass from the four sites. Areas 5 and 7 had the highest concentrations of total residual OCPs in the flooded soils, including dieldrin (385±241 μg/kg), sum of DDT, DDD, and DDE (7,173±1,710 μg/kg), and toxaphere (39,444±11,284 μg/kg). Sum of chlordane residuals was highest in area 5 (1,766±1,037 μg/kg). ANOVA indicated significant differences in location and fish muscle tissue concentrations for chlordane residuals, DDT residuals, and dieldrin. Fish from areas 5 and 7 had the greatest concentrations of chlordane residuals, DDT residuals, and dieldrin, which corresponded to the higher soil concentrations in these two areas. OCPs in muscle tissue were below the U.S. Food and Drug Administration action limits for human consumption. For three-year-old bass collected from Area 5, mean concentrations of chlordane residuals, DDT residuals, and dieldrin were 15–17 times higher in ovary tissue and 76–80 times higher in fat tissue compared with muscle tissue. Mean toxaphene levels in bass ovary and fat tissues were 9 and 39 times higher, respectively, than in muscle tissues. Tissue OCP concentrations were consistent with site OCPs, regardless of fish species.