典型铬渣污染场地健康风险评价及修复指导限值

通过对青海某化工厂铬渣污染场地钻孔采样,分析了样品质地及铬含量,得到场地的水文地质及铬污染状况.根据场地区域生活现状,运用美国环保局健康风险计算模型,评估了现有条件下该场地对周边居民的潜在健康风险.同时,结合场地的修复目标,应用地下水溶质运移方程及土壤中Cr6+的解吸曲线,探讨了场地污染物的修复指导限值.结果表明:场地表层0～4m为黄土状土,4～22m为砾砂,铬污染区域面积约4×104m2;现有条件下场地Cr6+对人体的健康风险值为9.39,需要对Cr6+进行修复治理,而Cr3+的健康风险值在可接受范围内;通过计算得到场地表层0～4m黄土状土Cr6+的修复值为60mg·kg-1;4～22m砾砂Cr6+修复值为15mg·kg-1.

The health risk assessment and remediation guide limit value of typical chromium slag contaminated sites

The chromium slag contaminated sites of a chemical plant in Qinghai was analyzed by drilling for the characteristics and chromium content, and received the hydrogeology and chromium pollution of contaminated sites. The potential health risk on the surrounding residents was assessed by EPA's Health Risk Calculation Model, which was based on the current situation of life. The guide limits value of the contaminated site remediation was discussed by using the groundwater and soil solute transportation equations and the desorption curve of Cr6+ according to the remedial goal. The results showed: 0~4m of the surface soil is the loess-like sand, 4~22m is the gravel, and the size of chromium pollution area was about 4×104m2. The heath risk value of Cr6+ for human body is 9.39, so it should be controlled and remedied, while that of Cr3+ is within the acceptable risk value range. The results obtained by calculation were that the restoration value of Cr6+ was 60 mg•kg-1 for the 0~4m loess soil and 15 mg•kg-1 for 4~22m gravelly sand.