The Fate of Organochlorine Pesticides in Water from Chaohu Lake, China

Abstract

Abstract. Forty samples of surface water and bottom water were collected from Chaohu Lake, China. The organochlorine pesticides (OCPs) in the samples were extracted by a solid-phase extraction (SPE) system and detected by Soxhlet extraction followed by gas chromatography (GC) using a mass-selective detector. The fate of OCPs in the water from Chaohu Lake was studied. The concentrations of total OCPs in the surface water and the bottom water varied from 0.17 to 2.89 ng L-1 and from 0.01 to 3.49 ng L-1, respectively, which were lower than total OCP concentrations detected in other lakes around the world. Sixteen types of OCPs were detected, with a concentration sequence of hexachlorocyclohexanes (HCHs) > dichlorodiphenyltrichloroethanes (DDTs)> hexachlorobezene (HCB) > chlordanes > endosulfans. The levels of all HCH and DDT isomers in the bottom water were higher than those in the surface water. Results suggested that the presence of DDTs could be attributed to residue from technical DDTs and the recent use of dicofol, as well as antifouling paints for ships, while HCHs were most likely primarily derived from aged technical-grade HCH and lindane.