三江源长江地表水水环境现状评价

Environmental Assessment for Water of Yangtse River of Source Area of Lantsang,Yellow and Yangtse River

目的了解三江源长江地表水水质状况,为保护该区脆弱的生态系统提供理论依据。方法在三江源长江地表水区域设10个监测断面,分别于2008年5月(丰水期)、8月(平水期)、10月(枯水期)采集水样。根据国家环保总局HJ/T91—2002《地表水和污水监测技术规范》确定水质监测指标。测定方法参照《中国环境保护标准汇编:水质分析方法》(2001)进行。根据GB3838—2002《地表水环境质量标准》Ⅰ类水质标准进行评价。结果三江源长江地表水的平均水温为8.5℃,pH值为8.27,高锰酸盐指数为0.73mg/L,化学需氧量(COD)为9.1mg/L,生化需氧量(BOD5)为2mg/L,氨氮为0.334mg/L,氟化物为0.166mg/L,硫化物为0.02mg/L,磷为0.03mg/L,六价铬0.004mg/L,挥发酚为0.002mg/L,总汞为0.00001mg/L,石油类为0.02mg/L,粪大肠菌群<20个/L,均符合GB3838—2002《地表水环境质量标准》Ⅰ类水质标准。结论三江源长江地表水水体未受到污染,水质良好。

Objective To know the situation of the water environment of Yangtse fiver of source area of Lantsang,Yellow and Yangtse River, and provide the theoretical basis for protecting the biosystem of this area. Methods Ten monitoring sections were selected in the investigated areas and the water samples were collected in May 2008, August 2008, October 2008 respectively. The sampling, determination and evaluation in the investigation were performed according to the related standard regulations. Results The water temperature was 8.5 ℃, pH value was 8.27, the index of KMnO4 was 0.73 mg/L, the concentrations of COD, BOD5, NH4-N, fluoride, sulfide, total phosphoric, Cr^6＋, phenol, Hg, petroleum were 9.1, 2, 0.334, 0.166, 0.02, 0.03, 0.004, 0.002, 0.000 01, 0.02 mg/L, respectirely; the count of fecal coliform 〈20 cfu/L. Conclusion No water contamination has been found in the source area of Lantsang, Yellow and Yangtse River.