Organochlorinated pesticide multiresidues in surface sediments from Beijing Guanting reservoir.

For the analysis of organochlorine pesticides (OCPs) in sediments and water, a multiresidue analysis method based on gas chromatography with electron capture detection (GC/ECD) was developed. Solid-phase extraction (SPE) using Oasis HLB cartridges was also applied in sample extraction. Mean recoveries were satisfactory with 72-103% and 71-103% for water and sediment, respectively. Twenty-one OCPs were analyzed in water and surface sediment samples from Beijing Guanting reservoir. Total concentrations of 21 OCPs were 16.7-791 ng/l (mean 234 ng/l), 275-1,600 ng/l (mean 644 ng/l), 5250-33,400 ng/kg (mean 13,000 ng/kg) in surface water, pore water and sediment (dry weight), respectively. P, p'-DDE, delta-HCH, aldrin, gamma-HCH and beta-HCH are the most abundant compounds in water while p, p'-DDE, o, p'-DDT, beta-HCH, delta-HCH, p, p'-DDT and aldrin accounted for about 85% of total 21 OCPs in sediment in Beijing Guanting reservoir. Concentrations of OCPs were high both in water and sediment samples in Beijing Guanting reservoir for municipal water supply. The data provides information on the levels and sources of OCPs in Guanting reservoir. The study indicated that measures should be taken to decrease OCPs residues in order to improve the quality of municipal water supply in Beijing.