Comprehensive Study On Water Polution In Ttypical Areas Around Taihu Lake

Lake Taihu is the third largest freshwater lake in China, which have been used as the important freshwater sources in the yangtze river delta on edge of chinese eastern coast. Its water quality and environmental conditions affect this area economic development. In recent years, with the fast development of industry and agriculture process , wastewater and domestic sewage without thorough treatment was discharged into Taihu Basin, which cause water environment system of Taihu Basin be damaged and water quality be worsen gradually. At present, the studies were focused on water pollution in Wuxi Meiliang bay of LakeTaihu, and the reports about the pollution in other typical areas were very little.In this thesis, water qualities were monitored, assessed and classified in typical areas around Lake Taihu, using single index factor, principal component analysis, et al, and eutrophication was assessed simultaneously; Enzyme- linked immunosorbent assay (ELISA) was employed for determinating Microcystin-LR pollution; Genotoxicity and estrogenic activity of water extract were analysed by molecular biological toxicity test; Distribution of Phthalates acid esters(PAEs) in typical areas around Lake Taihu was investigated, and PAEs were studied as typical pollutants on their estrogenic activity and effects on Liver Antioxidant Defense System of Carassius auratus. Therefor, this paper can offer scientific evidence for environmental assessment on typical areas effect on Lake Taihu. The main works were:1. Water qualities of typical areas around Lake Taihu wers analysed from March 2008 to February 2009, the results showed that the concentration of TN and TP in each sampling site exceed the Grade V of national standard(GB3838-2002), and water quality was evaluated for worse than Grade V by evaluation method"single index factor"; Correspondingly, using multi index evaluation, the water qualities of HuZhou Rv.(T4), Xin Gang Kou(T6), Suzhou Xukou bay(T12), Xiao Mei Kou(T5) were evaluated for GradeⅡ, and PingWang Brdg.(T3), Wuxi-Gonghu bay(T11), YiXing Ind.(T7), Wuxi-Meiliang bay(T10), Jiaxing Canal(T1) were for GradeⅢ, and YX Rv/Lake(T9), Wang-jiang Jing(T2), YiXing WWTP(T8) were for GradeⅣ; The water eutrophication appraisal result indicates that there were eutrophication in each sampling sites.2. ELISA was employed for investigating MC-LR pollution in typical areas around Lake Taihu. The MC-LR concentration in each sampling sites was detected from July 2008, and was higher in August and October, with the highest concentration of 0.66μg/L; there was not MC-LR detected from December 2008 to February 2009.3. Genotoxicity of water extract was detected by SOS/umu method, the result showed that a good dose-response relationship was observed between volume of water extract and induce rate in each sampling site. Induce rates of T1, T2, T3, T7, T8, T9, T10 were over 2, which showed water extracst had genotoxicity. The sensonal change characteristic of genotoxicity: pre-flood season > flood season.There was little change of genotoxicity on sites of stable pollution sources. Genotoxicity of water extract was significantly correlated to UV254 (P<0.01), and no correlations with CODMn, CODCr, TOC.4. Estrogenic activity of water extract was detected by Yeast Two-hybrid Analysis, the result showed that estrogenic activities of T2, T3 , T5, T6, T7, T8, T9, T10, T11's water extract were detected on observing months, with the range of 0.20~0.56 ng-E2/L.5. PAEs was investigated in typical areas around Lake Taihu, the result showed that the spatio-temporal distribution of PAEs in each sampling sites was uneven, Dibutyl phthalate(DBP), Butyl benzyl phthalate(BBP), Di 2-Ethyl Hexyl Phthalate(DEHP) were detected, with highest detectable concentration of DEHP.6. Estrogenic activity of PAEs was detected by Yeast Two-hybrid Analysis, the result showed that Dimethyl phthalate(DMP), Diethyl phthalate(DEP), Dioctyl phthalate(DOP) and DEHP had no estrogenic activity in the range of 0~10.0 g/L-DMSO; BBP and DBP had estrogenic activity with estradiol equivalent 0.97μg-E2 and 0.42μg-E2.7. With superoxidedismutase(SOD), catalase(CAT), glutathione peroxdase(GPX) glutathione S-transferase(GST) and malondialdehyde (MDA) as characteristic indexes, the effects of DBP and DEHP on the liver antioxidant defense system of Caras-sius auratus were studied, and the toxic mechanisms were discussed. The result showed that DEHP had more significantly effect on 4 enzymatic indexes than DBP; With oxidative stress of DBP and DEHP, SOD and CAT activity changes were more sensitive than GPX. GST played an important part in the detoxification process of DBP and DEHP. The MDA content increased sig-nificantly during experiment, which indicated that accumulation of lipid peroxidation products in vivo might be one of the most important toxic mechanisms of DBP and DEHP to Carassius auratus.