摘要
以北京某大型苯污染场地为例,详细介绍了如何开展层次化健康风险评估.同时,结合场地污染调查结果,比较了不同层次风险评价确定的土壤苯修复目标、修复量及修复成本的差异.结果表明,在1×10-6可接受致癌风险水平下,该场地第二层次风险评价确定的0～1.5 m深度范围内土壤苯修复目标为0.26 mg·kg-1、1.5～10 m范围内土壤苯修复目标为0.15mg·kg-1,相应的土壤修复量约为292 759 m3,修复成本约2.06亿元.但是,基于该场地苯污染区域土壤气中苯浓度进行的第三层次风险评价确定的0～1.5 m深度范围内土壤苯修复目标为2.6 mg·kg-1、1.5～10 m范围内土壤苯修复目标为1.5mg·kg-1,相应的土壤修复量约为153 222 m3,减少139 537 m3,修复成本为1.49亿元,减少了5 700万元,修复成本的降低远多于因开展第三层次风险评价所付出的约10万元的成本.因此,对于类似大型VOCs污染场地,开采第三层次健康风险评价能够节省大量修复成本、带来巨大的经济效益.
The procedures of implementing tiered health risk assessment approach were introduced in detail, and took a large-scale site polluted by benzene in Beijing as an example, the difference on the remediation target of benzene in soil, as well as the corresponding soil remediation volume and costs, were compared. The results indicate that the benzene concentration in soil within 1.5 m in depth and the one below should be remediated to 0.26 mg·kg-1 and 0. 15 mg·kg 1, respectively, in order to keep the cumulative carcinogenic health risk below 1 ×10^- 6 based on tiered Ⅱ assessment. However, according to tiered Ⅲ assessment result, which is based on the benzene in soil gas within the contaminated areas in the investigated site, the soil in the corresponding depth should only be remediated to 2.6 mg.kg-1 and 1.5 mg.kg 1, respectively. That means the soil remediation volume delimited on tiered Ⅲ assessment result is less than the one on tiered Ⅱ by 139 537 m3 and the corresponding remediation costs will be reduced by 57 million Yuan, meaning the enormous economic benefits compared to the costs （around 100 thousands Yuan） spent to carry out tiered m assessment in the site.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2013年第3期1034-1043,共10页
Environmental Science
基金
北京市科委重大项目(D08040900360804)
环境保护公益性行业科研专项(201009032)
关键词
层次化
苯
健康风险
效益评估
成本节约
tiered approach
benzene
health risk
benefits evaluation
cost saving
