Study On Inflow Rivers Pollution Characteristics, Estimation Of Non-Point Source Pollution In Lake Taihu Watershed

Lake Taihu has been plagued by pollution as a result of rapid economic growth in the surrounding region. To understand tempo-spatial patterns, controlling factors of the pollutant inputs, including nitrogen, phosphorus, from the outflow, inflow rivers into Lake Taihu, we analysed the changes of different forms of nitrogen, phosphorus concentration in15sections of the main the inflow rivers during years2009-2010. These results showed that:(1) TN concentrations were high in Lake Taihu Watershed. Therefore, controlling of TN pollution was important in Lake Taihu Watershed.(2) Based on the One-way multivariate analysis of variance between HS, XM, it was found that land use pattern, land Water-Cycle Model, proportion of water conservation forests in the two study areas were significantly different. There were significant difference of DTN, NH4+-N, TP, DTP, PP, CODMn between this two study areas. In addition, HS area displayed the strong point source pollution based on Seasonal Multivariate Analysis of water quality parameters, the Pearson Correlation Analysis between water pollution and rainfall. Meanwhile, the main pollutants in XM include TN, PN, NH4+-N leads this area shows the characters of non-point source pollution.(3) The average contents of heavy metals, Cu、Zn、Pb、Ni、Cr, are129.38mg/kg,207.74mg/kg,52.13mg/kg,28.26mg/kg,77.06mg/kg, respectively, average of the metals is higher than the TRV, Cu beyond800%. The average content of Zn, Pb, Cr, except Cu beyond144%, Ni under base line, is lies inner WCTMRL.(4) Cu contributing to ecological risk is main factor. Significant correlation was observed among the tested metals, which indicated that these heavy metals had the same source., the index of heavy metal Cu, Zn is the Moderately to heavily contaminated (MHC) Pb is the Moderately contaminated (MC). But the index of heavy metal Ni, Cr is the Uncontaminated to moderately contaminated (UMC) or the Uncontaminated (UC), so it is impossible that the pollutant Ni, Cr of Lake Taihu come from Wuyi canal.(5) Total nitrogen loading of non-point source pollution in Lake Taihu watershed is 398100tons/a, total phosphorus loading is55900tons/year. Total nitrogen, total phosphorus loading of non-point source pollution order of five areas as follows: North pollution area>West Zhejiang pollution area> West pollution area> South pollution area> East pollution area. Moreover, the total nitrogen pollution mainly comes from the cultivated land, the total phosphorus pollution mainly comes from the land for construction purposes.