拉萨市城郊农田土壤重金属污染测评

Evaluation of heavy metal pollution in the suburban farmland soil in Lhasa

本研究通过采样,对拉萨市城郊纳金乡、蔡公堂乡、夺底乡和羊达乡农田土壤所含重金属元素铜(Cu)、锌(Zn)、铅(Pb)、铬(Cr)、钴(Co)含量进行测量。利用单因子污染指数法和内梅罗综合污染指数法,并结合拉萨市土壤p H背景值及《中国土壤环境质量标准》(GB15618-1995)进行重金属污染评估。结论:1拉萨市城郊农田土壤除蔡公堂乡外,夺底乡、羊达乡和纳金乡均受到重金属铅、锌的轻度污染,铬元素维持在稳定的低水平。2除纳金乡外,其余各乡农田土壤钴含量超出全国平均水平,夺底乡已超出全国平均水平3倍多,纳金乡已接近全国平均水平。3拉萨市城郊农田土壤中重金属含量总体情况是:夺底乡>羊达乡>纳金乡>蔡公堂乡。

In the current paper, the contents heavy metals (Cu, Zn, Pb, Cr, Co) in the suburban farmland soil col?lected from Najin, Caigongtang, Duodi and Duodi in the outskirt of Lhasa City were measured. The heavy metal pollution in the farmland soil was evaluated by using single factor pollution index and Nemero comprehensive pollution index method combining with the background of pH value in the soil in Lhasa and“China's soil envi?ronmental quality standards ”(GB15618- 1995). The results showed that the suburban farmland soil in Lhasa have lightly been polluted by lead and zinc except Caigongtang, and the content of chromium is maintained at a stable low level;in addition to Najin township, cobalt content in the farmland soil of the other villages was ex?ceeded national average and cobalt content in the farmland soil samples collected from Duodi township has been exceeded more than three times that of the national average. the overall situation of heavy metal content in the farmland soil in Lhasa was Duodi>Duodi>Najin>Caigongtang.