拉萨河谷设施农业区水环境重金属含量及污染评价

Assessment of Pollution and Content of Heavy Metals in the Water in Facility Agriculture Region in the Lhasa River Valley,Tibet,China

为了解拉萨河谷设施农业区水环境中重金属污染水平及程度,文章对拉萨河谷设施农业区地下水和地表水中17种重金属(Cd、Be、V、Tl、Hg、Cu、Pb、Co、Ni、Cr、Fe、Sb、Zn、Mn、Ba、Ti和As)含量进行研究,并采用综合污染指数法对地下水和地表水中7种重金属(Cd、Hg、Cu、Pb、Ni、Zn和As)的污染程度进行了评价。结果表明,除A8点位的Zn含量符合《地表水环境质量标准》(GB 3838-2002)Ⅱ类标准外,拉萨河谷设施农业区其余各点位Cd、Pb、Cu、As和Zn含量均符合Ⅰ类水标准。Cr、Hg、As、Cu和Pb与pH存在显著或极显著相关性,说明pH对其有较大影响;不同重金属间有些存在相关性,说明它们之间可能具有一定的同源性。采用水体综合污染评价法表明,拉萨河谷设施农业区A1、A2和A7点位存在轻度污染,B1和B2点位为中度污染,且主要以Hg污染为主。

The aim of the current paper is to explore the pollution level and degree of heavy metals in water of fa-cility agriculture region in the Lhasa River Valley. The contents of Cd, Be, V, Tl, Hg, Cu, Pb, Co, Ni, Cr, Fe, Sb,Zn, Mn, Ba, Ti and As in ground water and surface water of the facility agriculture region in the Lhasa River Val-ley were analyzed respectively to explore the pollution level and degree of heavy metals in water of the region.The integrated pollution index were used to evaluate the contamination degree of Cd, Hg, Cu, Pb, Ni, Zn and As.Compared with GB 3838-2002, Cd, Pb, Cu, As and Zn at all the sampling sites fit the standards of category I wa-ter, while Zn content exceed the standards of category I water. The significant results also indicated that the pHcould has large influence on the distribution of Cr, Hg, As, Cu and Pb. Significant positive correlations werefound between some elements, which implied that these elements probably had common pollution sources. Theintegrated pollution index assessment showed that the water quality in the A1, A2 and A7 sampling sites state inlight pollution level while sampling sites B1 and B2 are moderately polluted with heavy metal. Hg was the mainpollution element in water at the facility agriculture region in the Lhasa River Valley.