| Organochlorine pesticides (OCPs) and Polychlorinated biphenyls (PCBs) are the first group of persistent organic Pollutions (POPs) to be controlled as specified in the Stockholm Convention on POPs. Once Presented at the environmental media,they, due to POPs possess toxic properties resist degradation, bioaccumulate and are transported and deposited far from their Places of release, where they accumulate in ecosystems for long periods, are becoming a great threat to human beings'subsistence, Propagation and sustainable development. Pollution caused by them has been the worldwide environment problem.Using the mixed solvent acetone and n-hexane as the extraction solvent soxhlet extraction for sediments samples, and Methylenechloride as the extraction solvent liquid-liquid extraction at Ph=7 for water samples. And purified with anhydrous sodium sulfate-silica gel-litmusless alumina column chromatographic carriing on the dichloromethane, we analyzed samples with the GC-ECD machine. It shows that 15 POPs (α-HCH,β-HCH,γ-HCH,δ-HCH,O,P'-DDT,P,P'-DDT,P,P'-DDD,P,P'-DDE,PCB28,PCB52,PCB101,PCB118,PCB138,PCB153,PCB180) the recovery rate of sediment samples ranged from 86.47% to 119.82%, and the standard deviation from0.0070 to 0.0974.The recovery rate of water samples ranged from 85.91% to 108.31%, the stander deviation from 0.0015 to 0.0537.To determine the compositional characteristics and potential sources of the POPs, the sediment samples and water samples were collected from Gong Lake. Following above method to analyze the sediment samples, the result shows that the total concentration of HCH in studying area ranged from 0.2502ng/g-9.8194ng/g dry weight. And the detectable ratio of a-HCH is 90.91%,β-HCH has the same ratio to theα-HCH.γ-HCH is 81.8%.δ-HCH has the lowest detectable ratio, is 54.55%. The a-HCH/γ-HCH indicate that the HCH concentration was due mainly to historical usage, lindane was used in the past in this area. The pollutant source was from agricultural activity. Analyzing the result of DDT, it shows that the concentration ofΣDT ranged from 0.3878-5.6142ng/g dry weight. The detectable ratio of P,P'-DDE is 90.91%. P,P'-DDD is 54.55%, P,P'-DDT is 45.45%, O,P'-DDT is 9.09%. The result of (DDD+DDE)/DDT and DDE/DDD show that the usage of something that contains DDT was not terminated.The concentration of PCBs ranged from 1.3922-7.0516ng/g dry weight. The detectable ratio of PCB52 was 100%, the PCB101 is 81.82%, and PCB28 is 72.73%. The PCB118, PCB138, PCB153 and PCB180 were not detected. The highest concentration of PCBs is PCB52, it ranged from 0.9571ng/g-6.3467ng/g dry weight. The pollution was caused by electrical power units (EPU) that were out of service.When we analyzed the water samples, the results show that the detectable ratio ofα-HCH is higher than the ratiot in sediment;β-HCH andδ-HCH have the same situation. But the ratio ofγ-HCH is lower than that in sediment; it is due to the different stability of HCH's isomer. DDT and its isomer were not detected. The results of PCBs indicate that the recovery ratio of PCB52>the ratio of PCB28>the ratio of PCB101>the ratio of PCB153. The main reason of the difference between PCB101 and PCB2g in sediment samples is that they have the different solubility.The highest concentration of persistent organic pollutions in water was in April, the lowest concentration was in August, the concentration made a little change in June. But the concentration of some positions in Gong Lake had different changes, and these changes show that the Wangyu River is the main pollution source of Gong Lake, the 6 position we collected samples was the influx area of POPs, there have the pollution leaked in the 11 position and 1 position. The key of protecting the Taihu Lake is protecting the rivers runs into the Taihu Lake and cultivating the consciousness of protecting environment. |
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