Distribution Of Different Forms Of Nitrgen And Organic Pollutants Biological Toxicity Effect In Sediments Of Qiantang Jiang River

As the largest river, Qiantang River got her first algae boom in 2004. The chemical industry, dyeing, metallurgy, paper and other industrial wastewater in this watershed riched in carbon, nitrogen, phosphorus and other nutrients, also contains large amounts such as heavy metals, polycyclic aromatic hydrocarbons(PAHs), polychlorinated biphenyls(PCBs) and other toxic substances, serious threat to the entire Qiantang River aquatic ecosystem.Take sediments from Hangzhou to Jiande in Qiantang River fro this study, Preliminary Discussion of characteristics of nitrogen and organic pollutants(PCBs) was made to supply some scientific information about sediments for Qiantang River pollution remediation.In this paper, 25 sediment samples from Hangzhou to Jiande of Qiantang River have been collected. Contente and distribution character of physicochemical property, grain size composition, forms of N, organic carbon, PCBs have been generally investigated. We also calculated the PCBs Toxicity Equivalent Quantities(TEQs), and made a preliminary exploration of toxic effect and ecological risk of the mixed organic pollutants in the sediments.According to the international classification system for soil texture the Qiantangjiang River sediments can be separated into 7 grades. The upstream sediments testure was quite similar, while quite different in the downstream.The level of OM content are very high in one or two sediments, but low in most sediments of Qiantang River, and the sediments from south had more OM the north in the same section of the river. According to the investigation of KTN, NH₄⁺-N and ON we found that the organic nitrgen(ON) is the main form of N. KTN and ON had same distribution characters, that is the content of this two form N are very close in the upstream while different in the downstream. The reason of very high contents of N in some sediments is because of the exterior pollution loading. By the analysis of the SPSS software, we found that, the content of all substance were closely correlated coposition of grain size; OM and all N were significantly related. Different forms of N were also closely linked.Total content of all PCBs 32 homologue in different Qiantang River sediments showed little different, 4, 5, 6-substituted biphenyl take most proportion of the total PCBs content The most PCBs homologue are PCB8(2,4'-EthCB),PCB118(2,3',4,4',5-PentaCB),PCB157(2,3,3',4,4',5-HexaCB). OM showed closely correlation to the content of 2, 3, 4, 5 chloro-biphenyl, the content of 2, 5 chloro-biphenyl and sum of PCBs are significantly related to the grain size composition. The main source of PCBs is the industrial effluent for the sediments located in sorth of Lingqiao and upsteam of Fuyang, and others came from non-point sources.The PCBs content in the sediments has been much higher than the EPA recommended sediment quality baseline, compare to the CCME environmental quality standards, the PCBs in few sediments samples had potential threat to the exposed organism. Calculated the TEQs of PCBs we found little different between sediments, the most TEQs came from PCB156, PCB157.Through comet assay of coelomocyte, we found that mixed organic pollutants in some sediment samples slight damages to earthworms will somatic cell DNA DNA damage level, PCBs content and TEQs showed a certain extent dose-response correlation.