典型涉污企业周边土壤重金属污染特征及潜在生态风险评价

分析和评价典型涉污企业周边土壤环境质量,对于加强企业用地环境风险管控,实施土壤重金属污染精准防控,进一步保障农产品质量安全具有重要意义。以18类典型涉污企业周边土壤为研究对象,对475家企业周边的2 017个监测样点进行土壤重金属Cd、As、Pb、Hg、Cr、Cu、Zn和Ni元素含量测定,并采用主成分分析法、Hakanson 潜在生态风险指数法进行分析及评价。结果表明:典型涉污企业周边土壤重金属污染以Cd、Pb和As元素为主,各元素含量超过土壤污染风险筛选值的样品比例为9.82%~31.0%,超过土壤污染风险管控值的样品比例为4.46%~13.1%,其次是Zn、Cu、Hg和Ni,Cr无明显污染;主要污染元素Cd、Pb、As、Zn和Cu来自相同污染源且主要分布在有色金属矿采选业(B9)、黑色金属冶炼和压延加工业(C31)、有色金属冶炼和压延加工业(C32)、生态保护和环境治理业(N77)等行业企业周边;黑色金属冶炼和压延加工业(C31)、有色金属矿采选业(B9)、有色金属冶炼和压延加工业(C32)等行业企业周边土壤重金属潜在生态风险等级较高,中等风险及以上比例分别为76.0%、53.0%和54.1%。可见,典型涉污企业周边土壤重金属存在一定程度的污染,尤其是有色金属矿采选业(B9)等采矿业以及黑色金属冶炼和压延加工(C31)等制造业等,污染程度高,潜在生态风险大,需要加强监测和管控。

Characteristics and Potential Ecological Risks of Heavy Metal in Soils Around Typical Pollution-Related Enterprises

Analysis and evaluation of soil environmental quality around typical pollution-related enterprises is of great significance for strengthening environmental risk control of enterprise land use,implementing precise prevention and control of soil heavy metal pollution,and further ensuring safety of agricultural products.This study analyzed characteristics of Cd,As,Pb,Hg,Cr,Cu,Zn and Ni in surface soils (0-20 cm) of 18 kinds of typical pollution-related enterprises (475 enterprises in sum),and assessed the potential ecological risks of heavy metals by the methods of Principal component analysis and Hakanson potential ecological risk index.The results showed that:Main elements of heavy metal pollution in soils around typical pollution-related enterprises were Cd,Pb and As,followed by Zn,Cu,Hg and Ni.Cr had no obvious pollution.Among the three main elements,the proportion samples whose contents exceed the soil pollution risk screening and control values ranged from 9.82% to 31.0%,and 4.46% to 13.1%,respectively.The main pollution of Cd,Pb,As,Zn and Cu were from the same pollution source and were mainly distributed around the non-ferrous metal mining and selection industry (B9),ferrous metal smelting and calendering industry (C31),non-ferrous metal smelting and calendering industry (C32) and ecological protection and environmental treatment industry (N77).The potential ecological risk of heavy metals in the soils surrounding enterprises of ferrous metal smelting and calendering industry (C31),non-ferrous metal mining and selection industry (B9),non-ferrous metal smelting and calendering industry (C32) was higher than that in soils around other enterprises,and the proportion of moderate risk or above was 76.0%,53.0% and 54.1%,respectively.It can be seen that typical pollution-related enterprises could polluted the nearby soils,especially the mining industry such as non-ferrous metal mining (B9) and manufacturing industry such as ferrous metal smelting and calendering (C31).These enterprises brought out serious pollution as well as high potential ecological risks,and needed to be further regulated.