我国铅锌冶炼厂周边土壤重金属污染特征及成因

Characteristics and Causes of Heavy Metal Pollution in Soil Around Lead-Zinc Smelters in China

收集了我国32个铅锌冶炼厂周边共1 551个表层土壤样品重金属检测数据,从全国尺度范围分析重金属污染特征及成因。结果表明,土壤中铅、锌、镉、砷、镍、铬、铜、汞的平均值分别为396.35、605.15、13.91、27.07、28.66、79.38、59.73和0.42 mg/kg,含量范围分别为9.33~9 280、23.29~25 238、0.032~556.9、0.7~422、0.25~357.8、5~584.7、4.51~2 027.5、0.007~7.9 mg/kg,以《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB 36600—2018)的第一类用地标准值为参考,铅、镉、砷、镍最大超标倍数依次为22.2、28.8、20.1和2.39倍。铅锌冶炼厂周边土壤重金属分布主要受大气沉降、方位、风向、距离梯度、地形和地域界限的影响。土壤重金属污染主要来自大气沉降,不规范的废渣堆存也会造成堆场周边土壤重金属污染。

Heavy metals data of 1 551 surface soil samples around 32 lead-zinc smelters in China were collected.The characteristics and causes of heavy metal pollution were analyzed from a national scale.The results show that the average values of lead, zinc, cadmium, arsenic, nickel, chromium, copper, and mercury in soil are 396.35,605.15,13.91,27.07,28.66,79.38,59.73 and 0.42 mg/kg.The content range of lead, zinc, cadmium, arsenic, nickel, chromium, copper and mercury are 9.33-9 280,23.29-25 238,0.032-556.9,0.7-422,0.25-357.8,5-584.7,4.51-2 027.5 and 0.007-7.9 mg/kg.Taking the standard value of the first category of land in the Soil Environmental Quality Construction Land Soil Pollution Risk Management and Control Standard(Trial)(GB 36600—2018)as a reference, the maximum excess multiples of lead, cadmium, arsenic and nickel are 22.2,28.8,20.1 and 2.39 times, respectively.The distribution of heavy metals is mainly affected by atmospheric deposition, azimuth, wind direction, distance gradient, topography and geographical boundaries.The heavy metal pollution in the surface soil mainly comes from atmospheric deposition, and the unregulated waste residue storage will also cause heavy metal pollution in soil around the storage yard.