The Study Of OCPs And PCBs In The Surface Water Of Beijing

Due to the massive usage and the poor management, organochlorine pesticides(OCPs) and polychlorinated biphenyls(PCBs) which banned in the Stockholm Convention extensively existed in environment compartments. Because of the great damage to human healthy and ecological environment, many researches have been done on the analysis of OCPs and PCBs around the world. The mostly used extraction methods in OCPs and PCBs analysis in environmental compartments are liquid-liquid extraction, Soxhlet extraction and ultrasonic extraction. Though these traditional methods have many advantages, such as stable recovery and easy operation, these methods were characterized astedious and time consuming over 20 h along with great toxic organic solvents consumption and higher detection limits. In order to overcome these disadvantages, we developed a rapid and accurate analytical method for the determination of 15 OCPs and 84 PCBs in surface water by combining accelerate solvent extraction(ASE),silica gel SPE purification and gas chromatography mass spectrometry.We firstly studied the adsorption capability of XAD-2 resin for OCPs and PCBs. The average recoveries for the target compounds were 68.6–120 % in 8.0g XAD-2 resin. The recoveries of silica gel procedure were 80.4–123%. The absorption capability of different materials and different brands filter for OCPs and PCBs were also studied.The potential influence parameters were investigated to get the optimum ASE efficiency, including static extraction cycles, extraction temperature, extraction solvent, and static extraction time. Finally, 3 static extraction cycles, 100℃ of extraction temperature, mixture of acetone and hexane(1:1, V:V) as extraction solvent, 10 min of static extraction time were used in our study. Under the optimized condition, the recovery and the relative standard deviation of the target compounds in spiked water were52.5–130% and 1.71–16.1%, respectively. And the method detection limits were characterized as 0.10–0.38 ng L-1.Subsequently, the developed method was applied to determine OCPs and PCBs in the Yuyuantan Lake and Tonghui river water in Beijing. The concentration of 15 OCPs were in the range of 1.10–16.3ng L-1, with an average of 8.19±6.53 ng L-1. The concentrations of 84 PCBs were in the range of 12.2–90.4ng L-1, with an average of 31.3±30.9 ng L-1. According to the composition of OCPs, the main source of OCPs pollution was the historical usage. And the concentrations of different homologues of PCBs were similar indicating that the sources of PCBs in surface water of Beijing were complicated with a combination of historical usage and long-range transportation from other areas.