农药企业场地土壤重金属污染状况及风险评价

Contamination and Risk Assessment of Heavy Metals in Soils from Pesticide Factory

为了解典型农药化工厂区及周边土壤的重金属含量分布及其环境风险,本研究选择京津渤地区某农药企业,对其厂区和周边表层土壤中Cu、Ni、Cd、Zn、Cr、Pb、Hg和As等重金属进行了监测,并采用内梅罗综合指数法、Hakanson潜在生态风险指数法和美国环保署(USEPA)的人体暴露风险评价方法进行了生态风险和健康风险评价。结果表明,企业内部存在明显的As污染,尤其是生产区土壤中As的浓度达到土壤三级标准的2.59倍,企业周边土壤也存在普遍的Cd、Pb和Hg累积现象,历史生产过程含砷辅料的使用是造成厂区As污染的关键原因。从潜在生态风险指数来看,企业内部生活区及周边土壤重金属平均总潜在生态风险水平为低度;生产区土壤的重金属总潜在生态风险水平为重度。所有重金属各种途径的非致癌风险叠加均未超过1,非致癌风险在安全范围内,其中主要的非致癌风险贡献元素为Cr、As和Pb。四种致癌重金属Ni、Cd、Cr和As的致癌风险指数从大到小排序为As>Cr>Ni>Cd,Cr、Cd和Ni在企业厂内以及周边土壤中的健康风险值均小于10-6,致癌风险较低,不会对人体造成致癌危害;As在厂内生活区以及厂外周边土壤的致癌风险水平在10-6-10-4之间,存在一定程度的致癌危害;然而,厂内生产区土壤中As的致癌风险值为1.2×10-4,有显著致癌风险。

In order to examine the concentrations of heavy metals and to evaluate their risk assessments in areas within and around pesticide industrial land, the contents of 8 trace heavy metals such as Cu, Ni, Cd, Zn, Cr, Pb, Hg and As were monitored and tested in soils of a pesticide factory in Hebei Province. The ecological and health risk assessments were analyzed by using the Nemerow pollution index, the potential ecological risk index and the human health risk assessment method established by USEPA. The concentration of As was very high in the factory area and the As in work area was 2.59 times higher than the national standard Ⅲ level. It can mainly due to the use of Arsenic-containing materials in its production history. Cd, Pb and Hg accumulations were also found in soil around the factory. The avreage total ecological risk assessments of heavy metals in soil of living area and outside of the factory were low, while the level in soil of the living area was high. The Non-carcinogenic risk was under the risk threshold and the main contributors were Cr, As and Pb. The carcinogenic risk of exposure was As 〉 Cr 〉Ni 〉 Cd, and the health risk of Cr, Cd and Ni were under risk threshold, while the health risk of As was within carcinogenic level in both living area and work area of the factory.