铅冶炼企业周边大气降尘中铅、镉、砷量及其对土壤的影响

The Quantum of Pb,Cd and As in the Ambient Air of Lead Smelting Enterprises and Their Effects on Soils

通过在2012年5月—2013年4月1个周期年内,对修复基地和对照点每月大气降尘中铅、镉、砷沉降量的监测,结果表明:修复基地大气降尘中铅、镉、砷含量明显较对照点高,年总沉降量分别是对照点的17.6倍、16.3倍和14.1倍,表明铅冶炼企业对基地大气降尘中铅、镉、砷含量影响显著;大气降尘中铅、镉、砷沉降量受位置和时间影响较大,在相距不到100 m的测点间,沉降量相差1倍以上,冬季主导风明显、地面植被少、二次扬尘大,使处于铅冶炼企业下风向的基地降尘中铅、镉、砷沉降量较大。沉降量时空不均匀与土壤污染不均匀现状一致,也验证了铅冶炼企业是基地大气和土壤重金属污染的主要来源。以降尘缸模拟土壤进行测算,结果表明大气降尘中镉对土壤污染速度最快,风险最大。

Monitoring of atmospheric deposition of Pb,Cd and As in the dusts during May 2012 to April 2013 indicated that,the concentration of these three elements in the dusts of remediation site were clearly higher than those of the control site,and the total annual dusts is 17.6 times,16.3 times,14.1 times more than control site.This results indicated that lead smelting factories have significant impact on the Pb,Cd and As content of base air.The atmospheric deposition of Pb,Cd and As is greatly influenced by location and time.The settlement values vary more than one time between two measuring points,which is less than 100 m apart.The reason why the base deposition under the wind in the lead smelting enterprises of Pb,Cd and As is higher than control sites is that the dominant wind is obviously,the ground vegetation is less and the secondary dust is big.Deferential settle-ment in location and time is consistent with the status of uneven soil pollution.This also verify the main source of heavy metal in base air and soil is come from lead smelting factories.We perform simulation using dust cylinder, through calculation we found Cd in atmospheric deposition is faster and higher risk to soil pollution than other el-ements.