Residues of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) and their environmental risks in surface sediments collected from upper reach of Huaihe River, East China, are investigated in this paper. Based on dry weight (dw), the concentrations of ΣHCH (α-, β-, γ- and δ-HCH) and ΣDDT (p,p'-DDT, o,p'-DDT, p,p'-DDE, p,p'-DDD) in sediments ranged from 1.95 to 11.05 ng g(-1) dw (mean 4.53 ng g(-1)dw) and 4.07 to 23.89 ng g(-1)dw (average 11.07 ng g(-1)dw), respectively. Compared with some published guideline values of organochlorine pesticides (OCPs) in sediments, the concentrations of HCHs were at safe levels while the residues of DDTs would pose adverse biological effects in this studied area. The distribution of OCPs in sediments indicated that the input of tributaries was important factor for Huaihe River. Levels of DDTs in the sediments were influenced by total organic carbon contents of sediments. The present study suggested that historical usage of lindane and technical DDT was the main reason for OCP residues in the sediments from both rivers and lakes. Furthermore, the composition of DDTs reflected fresh inputs of dicofol mixture in this region.
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