Assessment Of Surface Water Quality And Analysis Of Source In Yulin Energy Industry Base

The north of Shaanxi province is an important energy base in China. Exploitation of coal, petroleum, natural gas and rock salt causes an increasingly serious water pollution problem. In this study, sampling in major surface rivers(including Kuye river, Tuwei river, Yuxi river, Hongliu river, Lu river,Wuding river, Dali river, Xiaoli river) have been made to determine the routine index of water(including p H value, ammonia nitrogen and total phosphorus), heavy metals, polycyclic aromatic hydrocarbons and organochlorine pesticides. In this way, we can acquire the comprehensive information of surface water quality in energy base. At the same time, Water Quality Assessment combined with related specifications have been developed according to the results of determination.The results are as follows:(1) The over standard rate of NH3-N and CODCr in Kuye and Yuxi river are 60%~75.5%, which focus on coal mine and downtown such as Daliu river and Hebin garden. Furthermore, it is affected greatly by mine coking wastewater and domestic wastewater. Except total phosphorus in downtown, there is basically no over standard point in the overall water quality. Because Tuwei river is far away from the condition enterprise, the overall water quality conditions does not exist over standard phenomenon. CODCr and NH3-N in Lu river, Hongliu river, Xiaoli river and Dali river are overproof seriously in some sections, mainly focus on town downstream region, which are mainly influenced by wastewater in factories and downtown. The total phosphorus doesn’t overproof. While the over standard rate of CODCr and NH3-N in Wuding river is over 60%. The total phosphorus is in low content, primarily concentrated in import and town downstream region, which is affected greatly by tributaries and surface sources of itself.(2) The content of organochlorine pesticides in eight major rivers in Yulin exhibit similar characteristics. The maximum value of BHC and DDT in the whole region are 6.46ng/L and 0.35 ng/L, respectively, which are far below the standard limit of the range. The source indicate that there are no new sources in the selected regions, all of it are residuals.(3) Among the 8 surface rivers in Yulin energy base, the overall detection rate of heavy metal in Kuye River and Wuding River is comparatively higher than others. Among which, the detection rate of Pb and Cd in Kuye River reaches 71.43%, Hg and Cr6+ is 57.14%. At the same time, the detection rate of Cd and Cr6+ reaches 83.33%, Pd and Hg is 66.67% and 50%, respectively. According to the Ⅲ water limites standard of 《Surface Water Environment Quality Standard》, the whole over standard rate of heavy metal in Kuye River, Tuwei River, Yuxi River, Hongliu River, Lu River, Wuding River, Dali River and Xiaoli River is basically zero. That is to say, the rivers in energy base are substantially free from polluted.(4) The content of polycyclic aromatic hydrocarbons in surface water of energy base in Yulin distribute uneven, mainly focus on Kuye river, Yuxi river, Lu river and Wuding river. The overall content of polycyclic aromatic hydrocarbons is ranged from 43.99ng/L to 91.17ng/L in average value. Whereas the total toxic equivalent of Ba P is not exceed the limit of 2.8ng/L. Therefore, it doesn’t pose a direct danger to health. The source of pollution is mainly due to coking wastewater, incomplete combustion of fossil fuel and use of petroleum products.