Organochlorine Pesticides in Surficial Sediments of Haihe River

In the paper, the concentration of organochlorine pesticides (OCPs) in sediment samples collected from 9 sites of Haihe River, Tianjin, were analyzed quantitatively by using gas chromatography and a Ni63 electron capture detector (GC-μECD). HCHs ( -HCH, -HCH, -HCH, -HCH) and DDTs (p,p'-DDT, p,p'- DDE, p,p'-DDD) were detected in all sampling sites, with the mean concentrations of total OCPs being 67.3 ng·g-1 d.w. (range, 8.95~239.92 ng·g-1) and mean concentrations of HCHs and DDTs being 18.25 ng·g-1 d.w. (range, 3.30~75.96 ng·g-1) and 48.78 ng·g-1 d.w. (range, 1.57~221.57 ng·g-1), respectively. Compared with the world's other river/estuary systems, concentrations of HCHs and DDTs in surfical sediments from Haihe River were higher, which illustrates that the contamination of OCPs was serious in Haihe River. In addition, the possible pollution sources of organochlorine pesticides were investigated according to the isomers characteristics for HCHs and metabolites of DDTs. The ratios of -HCH to -HCH were ranged from 0.35~15.8, and the ratios of (DDE+DDD)/T-DDD were higher than 0.5, both of which indicated the main pollution source was the use of pesticide in agriculture in history. Our results show that organochlorine pesticide contamination in Haihe River sediments are mainly due to the runoff of OCPs applied in agricultural in history, and there is no new discharge of organochlorine pesticides into the river recently.