玻璃生产场地土壤中砷的污染特征及其概率风险评估

Soil Arsenic Contamination and Probabilistic Risk Assessment from a Flat Glass Plant Site

砷(As)主要通过采矿、冶炼和燃煤等工业过程进入环境,然而玻璃生产中使用大量含砷原料,却鲜见相关土壤污染的报道.为探究玻璃生产场地土壤中As污染及健康风险情况,采用统计分析、正定矩阵因子模型(PMF)、体外测试、蒙特卡洛模拟等方法,研究了曾进行50余年生产活动的某平板玻璃厂土壤中As的污染浓度、空间分布及来源,并进一步结合生物可给性和本土化暴露参数(体质量、室内暴露频率、室外暴露频率、每日空气呼吸量),计算了健康风险水平及风险控制值.结果表明:该平板玻璃厂493件土壤样品中As的超标率达21.5%,As最大浓度位于平拉车间,高达317 mg/kg,其中80.3%来自配合料泄露.土壤中As的生物可给性范围为10.24%~54.35%,土壤理化性质对生物可给性结果具有显著影响.As的致癌风险范围为2.23×10^(−7)~1.22×10^(−3),95%分位值为5.77×10^(−5),危害商范围为9.49×10^(−3)~56.08,95%分位值为2.62;相应地,基于致癌风险的As风险控制值为0.50~3.57 mg/kg,其5%分位值为0.75 mg/kg,略低于传统点评估方法(DRA)的风险控制值(1.13 mg/kg).参数敏感性分析结果表明,生物可给性对风险控制值计算结果的影响(−64.38%)最大,其次是体质量,成人与儿童的敏感性分别为10.96%及19.18%,其余参数的敏感性均小于10%.总之,玻璃生产场地土壤中As污染不可忽视,使用本土化的暴露参数,并且将生物可给性纳入现有健康风险方法有助于更加全面客观地评估其健康风险水平,可为环境管理提供决策依据.

Arsenic(As)mainly enters the soil environment through industrial processes such as mining,smelting,and coal combustion.Because the material is rich in As,glass production also release significant amounts of As into soil,but knowledge of soil As contamination in this environment is limited.In this study,we investigated As contamination in soil samples(n=493)collected from a more than 50-year-old glass production factory in the North China.The pollution characteristics,spatial distributions and source apportionment of As in the soil were studied using statistical analysis,positive matrix factorization(PMF),in vitro bioaccessibility(IVBA)test and Monte Carlo model.Health risk levels and risk control values were then quantified by coupling bioaccessibility and local exposure parameters including body weight,indoor exposure frequency,outdoor exposure frequency and daily air respiration.The results showed that approximately 21.5%of the samples exceeded the maximum permissible As level in soil,with the highest As concentration(about 317 mg/kg)observed at the Drawing Plant.Our PMF calculations indicated that 80.3%,10.5%,and 9.2%of As in the soil samples came from leakage of glass production units,coal gasification,and natural sources,respectively.The IVBA values of As ranged from 10.24%to 54.35%,which were affected by physicochemical properties of the soil.The carcinogenic risks and hazard quotient of As varied from 2.23×10^(−7)to 1.22×10^(−3),and 9.49×10^(−3)to 56.08,respectively.Their 95%interquartile value were 5.77×10^(−5),and 2.62,respectively.Meanwhile,the control values of As carcinogenic risk were 0.50-3.57 mg/kg,with a 5%tertile value of 0.75 mg/kg,which was slightly lower than the reported value(1.13 mg/kg)based on traditional deterministic risk assessment(DRA)methods.Parameter sensitivity analyses showed that bioaccessibility was the dominant factor,contributing 64.38%of the sensitivities,followed by child weight(19.18%),adult weight(10.96%),and the remaining other parameters(<10%).Our results suggest that soil As contamination at glass production sites cannot be ignored,highlighting that integrating local exposure parameters with bioaccessibility in health risk assessments can provide a more accurate understanding of As contamination in the soil environment.These data can provide theoretical reference for pollution control measures.