Concentration And Distribution Ofpcbs And Pahs In Water And Sediments From The Source Of The Qian Tang River,China

Persistent organic pollutants, with high toxicity,can caused serious harm to human health and the environment.Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), two kinds of typical persistent organic pollutants, have become a serious issue arousing global attention. This research selected the source of the Qian Tang river water system as the research object, and collected water, particulate matter and sediment samples in different times, respectively. Solid phase extraction was used to extrac water samples, while the the soxhlet extraction to the particulate matter and sediment samples, then the extracts of the samples that purified by chromatography were concentrated by a rotating evaporator to approximately2ml, and reduced to a volume of0.5ml under a gentle stream of nitrogen and detected by GC-MS.Through the study of the system of PAHs and PCBs, obtained the following results:(1)To the QiXi reservoir, the concentration of PCBs in the water-suspended particulate matter-sediment system were respectively ND-0.0770ng/L,1.9-4.50ng/g dw and0.94-3.76ng/g dw, and the concentration of PAHs in the same system were2.415-303.351ng/L,430.2-3929.4ng/g dw and26.17-2013.25ng/g dw, respectively. And in the source of the Qian Tang river, the concentration of PCBs were respectively0.0013-0.0355ng/L,0.15-11.9ng/g dw and0.32-7.86ng/g dw, and the concentration of PAHs were0.2806-70.9945ng/L,71.8-3978.9ng/g dw and273.9-3643.7ng/g dw. The two sampling points had the same trend that the thresidual concentration of organic pollutants were suspended particulate matter> water> sediments.(2) Concentration of QiXi reservoir, compared from the position of the sampling point, we could found that sample concentration in that palce with much human activities was higher than the others.There was not be a obvious seasonal change between PCBs and PAHs in the sediments from the temporal and spatial distribution, and concentration of water was lower than previous samples, while there were not be a unified regularity in the concentration of suspended particulate matter.We also found that the percentages of different monomers were different, the water was mainly low aromatic ring and the low chlorinated biphenyls, and particulate matter and sediments were just in the opposite.(3) Concentration of the source of water from the Qian Tang river, compared from the position of the sampling point, we could find that sample concentration in that place with much human activities was higher than the others. Concentration of PCBs and PAHs on the seasonal variation was December higher than April. The percentages of organic monomer showed that the water phase was mainly low aromatic ring and the low chlorinated biphenyls, and particulate matter and sediments were just in the opposite.(4) Sediments collected from QiXi Reservoir in the organic matter fraction in the range of3.6%-7.4%, Sediments collected from Qian Tang River were1.58%-4.7%, there were not a significant correlation between them.(5) Biological toxicity evaluation method was used to assessing ecological risk about PCBs and PAHs which collected from QiXi Reservoir and the source of the Qian Tang river. Both of them had low ecological risk, but there were also some differences between them. That was because the main pollution source in QiXi reservoir was sanitary sewage, and the source of the Qian Tang river were sanitary sewage and industrial sewage.