某废铅蓄电池炼铅遗留场地土壤重金属污染特征及健康风险评价

Heavy metal pollution characteristics and health risk assessment of soil from an abandoned site for lead smelting of waste lead batteries

以某典型废铅蓄电池非法炼铅污染场地为研究对象,采用综合污染指数法、潜在生态指数法以及人体健康风险模型分别对场地土壤中铅和砷污染特征以及健康风险进行评价,并结合暴露吸收生物动力学模型(IEUBK)评估场地周边儿童的血铅水平。结果显示:研究区各点位土壤中铅和砷浓度平均值分别为4.67×10^(4)和2.64×10^(2) mg/kg,显著高于河南省土壤背景值,分别超过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)》二类用地风险筛选值的58.37倍和4.41倍;各点位的综合污染指数和潜在生态指数依次为废旧铅蓄电池拆解区>贮存区>铅块成型区,除铅块成型区土壤砷为轻度污染外,其他区域土壤中铅和砷均属于重度污染,存在极强的潜在生态风险;经3种暴露途径对成人和儿童造成的致癌、非致癌威胁依次为经口摄入>皮肤接触>呼吸吸入,各点位砷的致癌风险大小依次为炼铅炉区>废铅蓄电池拆解区>储存区>铅块成型区>10^(-6);铅和砷对成人和儿童非致癌风险总指数最大分别为25.00和160.69、1.73和11.71,其中铅对儿童的非致癌风险更加明显,二者均高于美国国家环境保护局推荐的最大可接受水平,对附近居民存在极强的潜在健康风险;IEUBK模型计算的儿童血铅浓度超过100μg/L的概率高达99.99%,均远高于5%的安全概率限值。

The contaminated plot left by a typical illegal lead refining site for waste lead batteries was taken as the research object.The pollution characteristics of lead and arsenic and health risk in the site soil were analyzed and evaluated by using the comprehensive pollution index method,the potential ecological index method,and the human health risk assessment model,and the children's blood lead levels were evaluated combined with the integrated exposure uptake biokinetic(IEUBK)model at the same time.The results indicated that the mean values of lead and arsenic in the soil at all sites in the study area were 4.67×10^(4) and 2.64×10^(2) mg/kg,respectively,which were significantly higher than the soil background values in Henan Province and exceeded the risk screening values of Soil Environmental Quality-Risk Control Standard for Soil Contamination of Development Land(Trial)(GB 36600-2018)for ClassⅡland by 58.37 times and 4.41 times,respectively.The comprehensive pollution index and potential ecological index in various points of the research area followed the order of waste lead battery dismantling area>storage area>lead block molding area.Except for the lead block molding area where the soil arsenic was lightly polluted,the lead and arsenic in the soil of other research areas were heavily polluted,and there was an extremely strong potential ecological risk.Meanwhile,the carcinogenic and non-carcinogenic risks of heavy metals in three exposure pathways followed the order of ingestion of soil>dermal absorption of soil>inhalation of soil.The total cancer risk index of arsenic at each point was found to follow the order of lead smelting furnace area>waste lead battery dismantling area>storage area>lead block molding area>10−6.Lead and arsenic levels had a significant effect on the maximum total non-carcinogenic risk indices,counting 25.00,160.69,1.73,and 11.71 for adults and children,respectively,with the non-carcinogenic risk of lead to children being more obvious.Both were higher than the US EPA's maximum acceptable level,and there was an extremely strong potential health risk to nearby residents.In addition,the probability of children's blood lead concentration exceeding 100µg/L was as high as 99.99%,calculated by the IEUBK model,which was much higher than the safety probability limit of 5%.