辽西滨海矿集区重金属污染状况及原因

Soil Contamination from Heavy Metals in West Liaoning Coastal Multiplex Mining Area

基于环境地球化学方法对辽西滨海矿集区的金属矿产开发区、冶炼厂附近土壤重金属污染状况进行了研究,结果表明,Cu,Pb,Zn,Cd的质量分数最高值达到0 0236%,0 0535%,0 1473%,0 0012%,多数土壤表层重金属元素的质量分数高于区域土壤背景值,4种元素分别是区域背景值的1 34～10 67倍,1 20～25 59倍,0 49～23 31倍,1 87～82 8倍·Cu,Pb,Zn,Cd元素的质量分数与5%HNO3浸提态的质量分数间相关性较好·采矿飘尘、废岩、尾矿泥等人为污染源是区域土壤重金属污染的主要来源,且随着距污染源距离的增加,表层土壤重金属的质量分数降低·

Based on the methods of environmental geochemistry, an investigation was carried out on the soil contamination from heavy metals in the multiplex metal mining area and adjacent tilled land in West Liaoning Coastal Zone. The result indicated that highest contents in mass fraction of Cu, Pb, Zn and Cd are up to 0.0236%,0.0535%,0.1473% and 0.0012%, respectively. The contents in mass fraction of Cu, Pb, Zn and Cd in top soil are mostly higher than the corresponding background values of the zone, i.e., 1.34～10.67, 1.20～25.59, 0.49～23.31 and 1.87～82.8 times as larger as the background values, respectively. It was proved that there is a comparatively close exponential correlation between the mass fraction of the four elements and those of them leached out in 5% HNO_3 solution. In the zone the sources of soil contamination from heavy metals are mainly the free dust during mining, tailings and waste sludge, and the mass fractions of such heavy metals in top soil decrease with the increasing distance away from the contamination sources.