冶炼企业影响的土壤-水稻系统中重金属分布特性及污染评价

以苏南某冶炼厂原址场地附近土壤、水稻为对象,研究了土壤及水稻籽粒中重金属（Cu、Pb、Cd）污染状况及其迁移、累积特征。结果表明,研究区土壤重金属综合污染指数均大于3,污染等级超过5级,属重度污染且各重金属间污染程度呈现Cd〉Cu〉Pb的特征,水稻籽粒中重金属Pb、Cd超标严重。在迁移、累积方面,表层土壤重金属呈现出由东南向西北方向扩散的趋势,且向下迁移及在水稻籽粒中累积的趋势明显,各重金属在水稻籽粒中富集能力的大小顺序为Cu〉Cd〉Pb。

Pollution Assessment and Distribution Characteristic of Heavy Metals in Rice Paddy Systems Around Metal Smeltery Area

The transportation and accumulation characteristics of heavy metal（ Cu,Pb,Cd ） in soil and paddy rice grain around Metal Smeltery in south of Jiangsu Province were investigated in this paper. The result showed that the heavy metals synthesis pollution index in research area was grater than 3 and the pollution degree was over 5 levels, characterized by the severest category. Among each heavy metals, degree of pollution was represented as a trend of Cd〉Cu〉Pb. The exceeding standards of Pb, Cd in paddy rice grain was more serious than those in other samples. On the spatial dynamics of heavy metal transportation in soil of studied area, heavy metal in surface layer diffused from southeast to northwest and transported to under layer. It was obvious that heavy metal tended to aecumulate in paddy rice grain, with an accumulative capability of Cu 〉 Cd 〉Pb. Therefore, the pollution of heavy metal in soil could eventually threat food safety seriously.