Residues and Distribution of Organochlorine Pesticides in Water and Suspended Particulate Matter from Hangzhou Bay, East China Sea.

The concentrations, distribution, and possible sources of organochlorine pesticides (OCPs) in Hangzhou Bay, East China Sea, were studied by analyzing water column and suspended particulate matter (SPM) samples from 13 sites. The results showed that OCP contamination remains widespread in the area. The OCP concentrations were 2.52-27.99 ng/L in the SPM samples and 1.35-26.36 ng/L in the water column samples. Pattern analysis suggested that both fresh and weathered hexachlorocyclohexane (HCH) were present. Low α-HCH/γ-HCH ratios and high β-HCH and γ-HCH levels contributed to the total HCH concentrations in both the water column and SPM samples. High p,p'-dichlorodiphenyltrichloroethane (DDT)/o,p'-DDT ratios and low (dichlorodiphenyldichloroethylene + dichlorodiphenyldichloroethane)/DDT ratios were found, reflecting a "dicofol-type" DDT input pattern, This suggested that new DDT inputs are occurring because of dicofol still being used in the area.