宜宾市江安县稻田土壤重金属现状评价

Current Status Assessment of Paddy Soil Heavy Metals in Jiang'an County,Yibin City

为了解宜宾市江安县稻田土壤重金属现状,以土壤中常见且与人类密切相关的8种重金属元素(砷、镉、铬、铜、汞、镍、铅、锌)为研究对象,对不同方位、不同类型的表层土壤及对应区稻米中重金属元素进行了检测,并参照相关背景值和国家标准评价土壤环境质量及重金属污染程度。以国家土壤二级标准值为参照,该地区镉污染最严重,受污染比例高达77.1%,根据内梅罗综合污染指数评价结果,约1/3样点存在生态安全隐患。以背景值为参照,江安县重金属潜在生态风险指数较低,为134.59,处无风险状态。单项风险系数大小为:汞>镉>砷>铅>铜>镍>铬>锌,潜在生态风险指数在空间上分布规律为:北部>中部>南部,交通干道区>农业耕种区>工业集中区>自然保护区,平地>河漫滩>丘陵。

In order to understand the current status of heavy metals in paddy soil of Jiang＇an County, Yibin City, eight common heavy metals （As, Cd, Cr, Cu, Hg, Ni, Pb, Zn） in soil which are closely related to human have been studied in this paper. The contents of these heavy metals in surface soil in different positions and different types are measured. And according to related background values and national standards, the soil environmental quality and pollution level of heavy metals are assessed. Compared with the second level of the national environment quality standard for soils, the pollution of Cd in this region was the most serious, and the proportion of polluted samples was up to 77. 1%. According to the results of the Nemerow comprehensive pollution index evaluation, one - third of samples are at potential ecological risk. Compared with the background value, the level of potential ecological risk from the heavy metals was low in this area, with a risk index of 134. 59, revealing a safe status. The decreasing order of the single coefficients is Hg, Cd, As, Pb, Cu, Ni, Cr, Zn. And in space distribution, the decreasing sequence of potential ecological risk from heavy metals is North 〉 Middle 〉 South, Traffic trunk 〉 Farming area 〉 industry concentrating area 〉 Nature reserve, Flat 〉 Floodplain 〉 Hill.