重金属铅、铬在土壤中的迁移特征——以泉州市为例

泉州市地处福建省东南部,工农业均比较发达。随着经济的发展,工矿企业遗留下来的污染问题也愈发突出。选择重金属Pb和Cr为研究对象,通过土柱实验和Hydrus-1D软件模拟,研究其在红壤和风沙土中的迁移特征。结果表明:重金属Cr在土壤剖面中的迁移速率和迁移量变化明显,尤其是风沙土,重金属Cr可以在两个月左右迁移至土壤剖面底部(80cm土层厚度)进入地下含水层;而重金属Pb在土壤剖面中的迁移速率很慢,迁移量也不大,污染源产生的污染物绝大多数在研究期内均被表层土壤吸附。因此在场地污染调查、评价和修复时,重金属Pb主要应该针对污染场地表层土壤层,而重金属Cr主要应考虑地下水,尤其是风沙土区域的地下水,且应于污染初期进行污染控制。

Migration Features of Heavy Metal Pb and Cr in Soil-A Case Study of Quanzhou City

The Quanzhou City is situated in southeastern part of the Fujian Province possesses well developed industry and agriculture.With the development of economy,the pollution issues left behind by industrial and mining enterprises are more prominent.Taking the heavy metal Pb and Cr as the subjects investigated,through soil column experiment and Hydrus-1D software simulation have studied their migration features in red loam and aeolian sandy soil.The result has shown that the migration rate and migrated mass of heavy metal Cr in soil section varied obviously,especially in aeolian sandy soil;Cr can be migrated down to soil section bottom within about 2 months(soil thickness 80 cm)and entered into aquifer below.While heavy metal Pb migration rate in soil section is very slow,migrated mass not large,overwhelming majority of pollutants from pollution source have been adsorbed by topsoil during the study period.Thus during the site pollution investigation,assessment and remediation,heavy metal Pb should be mainly aimed at topsoil of pollution site,while heavy Cr should be mainly considered in groundwater,especially groundwater in aeolian sandy soil area,and to control pollution during initial stage.