Residues and ecological risks of organochlorine pesticides in Lake Small Baiyangdian, North China.

The levels of hexachlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) in the water, suspended particulate matter (SPM), and sediments from Lake Small Baiyangdian were measured by gas chromatograph with a (63)Ni microelectron capture detector. The residual levels of the total HCHs in the water, SPM, and sediments were 1.59 ± 2.24 ng L(-1), 25.42 ± 1.72 ng g(-1) dw (dry weight), and 0.86 ± 1.44 ng g(-1) dw, respectively. DDTs were not detected in the water samples. The concentrations of total DDTs were 158.79 ± 1.67 ng g(-1) dw in SPM and 0.46 ± 1.97 ng g(-1) dw in the sediments. Compared to other areas in China and abroad, the levels of residual HCH and DDT were relatively low in the water and sediments, but they were moderate to high in the SPM. Organic carbon partition coefficient values for HCH in this study were higher than previously published values and may reflect new input in this area. The residual HCHs in this area could be derived from a mixture of technical HCH and lindane because ongoing lindane use may be occurring. DDT in the majority of the study area was primarily attributed to historical discharge, but some regions may be receiving new input. The ecological risks of γ-HCH in the water were very low according to species sensitivity distribution models. The concentrations of HCH and DDT in the sediments from the study area did not exceed the sediment quality guidelines, which indicate little risk for benthic organisms.