Occurrence of selected organochlorine pesticide residues in surface sediments from the Velke Kozmalovce, Ruzin, and Zemplinska Sirava water reservoirs, Slovakia

Surface sediment samples from three water reservoirs of Slovakia were analyzed for selected organochlorine pesticides (OCPs). Concentrations of total dichlorodiphenyltrichloroethanes (ΣDDTs) in the sediments from Velke Kozmalovce, Ruzin, and Zemplinska Sirava ranged from 12 to 24 ng g^-1, 5 to 28 ng g^-1, and 1 to 20 ng g^-1, respectively, with the exception of one sediment sample from Zemplinska Sirava, having anomalously high concentration of ΣDDTs (526 ng g^-1). Concentrations of hexachlorobenzene (HCB) in the sediments from these water reservoirs were generally lower and ranged from 0.3 to 9 ng g^-1. Other organochlorine pesticides such as mirex, lindane and heptachlor were not detected in the surface sediments. Ratios of DDT/(DDE + DDD) were lower than 1.0 in majority of the sediment samples indicating that the degradation of the parent DDT occurred significantly and DDT in the sediments from the studied water reservoirs was derived mainly from the weathered agricultural soils. Moreover, ratios of DDD/DDE indicated that the parent DDT was degraded under aerobic conditions before depositing into the sediments of these water reservoirs.