某电镀企业土壤重金属污染特征及健康风险评价

Pollution characteristics and health risk assessment of heavy metals in soil at an electroplating plant

电镀行业是重金属污染的重点监管行业,其生产过程往往伴随污染物的“跑、冒、滴、漏”现象,这使得大部分电镀企业及其历史用地成为了重金属污染的高风险区域。以成都市某电镀企业为研究对象,采用Muller地积累指数法、潜在生态危害指数法对土壤中重金属污染特征进行分析评价,结合空间分析方法对超标重金属分布特征进行探究并开展健康风险评价,以为电镀企业的土壤污染风险管控和修复以及职工职业健康保护提供科学依据。结果显示:土壤Cr超过了DB 512978—2023《四川省建设用地土壤污染风险管控标准》第二类用地筛选值,Cr^(6+)含量超过了GB 36600—2018《土壤环境质量建设用地土壤污染风险管控标准(试行)》第二类用地筛选值;Hg在表层土壤的地积累指数大于1,为偏中度污染,Cr在各土层均为轻度污染;研究区域内的8种重金属元素,除Cd、Hg外,其余重金属的潜在生态风险危害程度均为低风险;经口摄入土壤和吸入土壤颗粒物的Cr^(6+)致癌风险分别为6.31×10^(-5)、3.10×10^(-5),吸入土壤颗粒物的Cr非致癌危害商为1.25,均超过可接受水平;选用10^(-6)及1分别作为致癌风险、危害商的可接受水平计算研究区域Cr^(6+)及Cr的风险控制值,得出研究区域Cr^(6+)风险控制质量比为3.68 mg/kg,Cr风险控制质量比为3000 mg/kg。

This study focused on an electroplating enterprise in Chengdu as the research subject.Soil samples were systematically collected from 18 locations within the study area,and concentrations of heavy metals—As,Hg,Cr,Cr^(6+),Ni,Cd,Cu,Pb,and Zn—were determined.The Muller soil accumulation index method and the potential ecological hazard index method were employed to analyze and evaluate the characteristics of heavy metal pollution in the soil.Additionally,spatial analysis was conducted to explore the distribution patterns of excessive heavy metals and to carry out a health risk assessment.The results indicated that,with the exception of Cr and Cr^(6+),which exceeded the screening values for Type II land according to the Soil Environmental Quality-Risk Control Standard for Soil Contamination of Development Land(GB 36600—2018)and the Risk Control Standard for Soil Contamination of Development Land in Sichuan Province(DB 512978—2023),the concentrations of other heavy metals did not exceed the established standards.Compared to the background values for Sichuan Province,the concentrations of Cd,Cu,Ni,Cr,and Zn were significantly higher,with maximum values being 4.68,6.6,8.37,48.9,and 16.22 times the background levels,respectively.The soil accumulation index for Hg in the surface soil exceeded 1,indicating moderate pollution,while Cr exhibited slight pollution across all soil layers.As and Pb showed no signs of pollution in any of the soil layers.With the exception of Cd and Hg,the potential ecological risks associated with the other heavy metals in the study area are assessed as low.Based on the characteristics of current enterprises,historical land use,and the test values of the samples from this study,it is preliminarily speculated that the potential ecological risks of Cd and Hg are primarily due to deviations from local background values.The carcinogenic risks associated with oral ingestion and inhalation of Cr^(6+)soil particles were determined to be 6.31×10^(-5)and 3.10×10^(-5),respectively.The non-carcinogenic hazard quotient for inhalation of soil particles was calculated to be 1.25,both of which exceed the acceptable levels.For this analysis,10^(-6)and 1 were used as the acceptable levels for carcinogenic risk and hazard quotient,respectively,in order to calculate the risk control values for Cr^(6+)and total Cr in the study area.The results indicated that the risk control values for Cr^(6+)and Cr in the study area were 3.68 mg/kg and 3000 mg/kg,respectively.