贵州草海农业土壤重金属污染的生态危害评价

Ecological Risk Assessment of Heavy Metal in Agricultural Soil in Caohai of Guizhou

为考察贵州草海农业土壤污染情况和对生态环境的影响,在草海农业区布设了56个取样点,分析测试了土壤pH和重金属的含量,采用单项污染指数和综合污染指数法对土壤环境污染状况进行了土壤重金属污染生态危害评价.结果表明：草海东南区和西南区Cd综合污染指数均大于3.0,为严重污染;东北区和西北区Pb、Cu、As、Hg中4种重金属综合污染指数在2.0～3.0,为中污染;单项污染指数计算结果显示,4个区土壤重金属平均综合污染指数为3.13,污染程度为严重污染,农业土壤重金属单项潜在生态风险指数从大到小为Cd＞ Hg＞As＞Cu＞Pb;四区多种重金属潜在生态风险指数RI由高到低为东南区（233.74）＞西南区（163.93）＞西北区（159.32）＞东北区（104.53）.

To investigate the agricultural soil contamination status and effects on entironment in Caohai of Guizhou,the soil of 56 sampling points was assessed by using the present situation and potential ecological risk assessment of heavy metal in agricultural soil.The results showed that pollution index of Cd in south-east and south-west areas of Caohai were over 3.0 which meant severe contamination.The multifactor pollution index of Pb,Cu,As and Hg was 2.0～3.0 in the north-east and north-west areas which meant moderate pollution.The calculation of single pollution index showed that the average multifactor pollution index of heavy metal was 3.13,which was of high contamination level.The single potential ecological risk index of heavy metal was Cd＞Hg＞As＞Cu＞Pb,while the multifactor potential ecological risk index was south-east（RI=233.74）＞south-west（RI=163.93）＞north-west（RI=159.32） ＞north-east （RI=104.53）.