Distribution and ecological risk evaluation of organochlorine pesticides in sediments from Xinghua Bay, China

The concentrations of organochlorine pesticides (OCPs) in sediments from Xinghua (兴化) Bay, Fujian (福建) Province, China, were determined. The OCP concentrations ranged from 2.48 to 313.88 ng/g, with a more serious contamination in the upper sediment. But the OCP concentration in the upper layer was less than that in the lower sediment at the exit of the bay due to the influence of the Coriolis force. At the joint of the internal and external bays, OCPs accumulated abundantly because of freshwater and seawater mingling. The isomer percentage combined with isomer ratios indicated that DDTs (dichlorodiphengltrichloroethanes) were mainly derived from long-term weather soils, while lindane was introduced recently to the bay. The rivers flowing into the bay contributed more to DDT and HCH (hexachlorocyclohexane) contamination, especially at low tide. Compared with the corresponding quality guidelines from Ingersoll, the sediments from Xinghua Bay were likely to pose biological impairment and should be taken into account.