冶炼厂烟囱降尘农田土壤重金属含量及潜在生态风险评价

Heavy Metal Content and Potential Ecological Risk Assessment of Farmland Soil with Chimney Dust from Smelter

为了研究冶炼厂下风向烟囱降尘对农田土壤重金属污染影响程度,以济源市某一冶炼厂工业烟囱下风向降尘覆盖农田土壤为研究对象,依次对距离该厂烟囱大约750~3 000 m的7个农田研究区(P_(1)-P_(7))土壤中重金属(Hg、As、Pb、Cd、Cu、Zn、Ni、Cr)含量进行污染状况分析,采用了单项潜在生态风险指数法和综合潜在生态风险指数法对冶炼厂下风向烟囱降尘土壤中重金属的潜在生态风险进行评价。结果表明,在3 km^(2)研究区域内,距离冶炼厂越近土壤重金属含量越高,Pb、Cd为重度污染,超过了《土壤环境质量农用地土壤污染风险管控标准》(GB 15618—2018)农用地土壤污染风险管制值的1.2倍,距离冶炼厂烟囱下风向P_(1)区土壤中重金属As、Pb、Cd、Cu、Zn超过土壤环境质量农用地土壤风险筛选值,Cd在浓度值均超过农用土壤污染风险管制值1.8倍,As平均浓度值超农用土壤污染风险管制值1.7倍,Pb、Cu和Zn污染较严重,Cd、Hg对综合指数(RI)贡献值较大分别为68.63和22.4。单项潜在生态风险指数评价结果显示,Cd存在极严重的潜在生态风险,Pb、Cu存在较严重潜在生态风险,冶炼厂下风向土壤中综合潜在生态风险指数评价显示,冶炼厂下风向降尘土壤重金属具有较强的生态风险。

In order to study the effects of downwind chimney dust on heavy metal pollution in farmland soil,the paper takes the dust from the industrial chimney of a smelter in Jiyuan City as the research object.The pollution status of heavy metals(Hg,As,Pb,Cd,Cu,Zn,Ni and Cr,)in soil of 7 farmland research areas(P_(1)-P_(7))about 750—3000 m away from the chimney of the plant were analyzed successively.The single potential ecological risk index method and the comprehensive potential ecological risk index method were used to evaluate the potential ecological risk of heavy metals in the downwind chimney dust soil of the smelter.The results showed that within the research area of 3 km^(2),the closer the distance to the smelter,the higher the heavy metal content in the soil.The severe pollution of Pb and Cd exceeded the control value of the soil pollution risk of agricultural land by 1.2 times according to the standard for the control of soil environmental quality and soil pollution risk of agricultural land(GB 15618—2018).The heavy metals of As,Pb,Cd,Cu and Zn in soil of P_(1) area downwind from the smelter chimney exceeded the soil environmental quality screening value of agricultural land soil risk.The concentration value of Cd was 1.8 times higher than the control value,and As was 1.7 times higher than the control value.The pollution of Pb,Cu and Zn were serious.The contribution values of Cd and Hg to the comprehensive index(RI)were 68.63 and 22.4,respectively.The evaluation results of single potential ecological risk index showed that Cd had serious potential ecological risk,while Pb and Cu were higher.The comprehensive potential ecological risk index evaluation of the downwind soil of the smelter showed that the heavy metal in the downwind dust-falling soil of the metallurgical plant had strong ecological risk.