基于住宅用地规划及建筑结构暴露模型的场地健康风险评估

Health Risk Assessment Based on the Exposure Model with Residential Site Planning and Building Structure

以某拟建高层住宅的苯污染场地为例,结合场地土壤环境调查结果以及场地用地规划和高层住宅结构的特点,修正了通用污染暴露模型,构建了住宅用地规划及建筑结构暴露模型,分别采用两种污染暴露模型对该污染场地的健康风险进行了评估,并比较了两种污染暴露模型下该污染场地土壤中苯的健康风险水平、修复目标、修复量和修复费用的差异。结果表明:两种污染暴露模型的评估结果均显示该污染场地土壤中苯的健康风险高于可接收水平(1×10^(-6)),须对污染场地进行修复;采用通用污染暴露模型评估时,评估过程较为简单,但评估结果相对保守,可能会导致污染场地的过度修复,而采用住宅用地规划及建筑结构暴露模型评估时,该污染场地土壤中苯的修复目标值提高了约240倍,污染土壤的修复量减少了约82.03%,土壤修复费用减少了约86.87%,其评估结果比通用污染暴露模型更具科学性。可见,对于污染场地风险评估项目,应结合场地用地规划及建筑结构特点对现有污染暴露评估模型进行修正,以避免评估结果偏离实际。

Taking aproposed high-rise residential site contaminated by benzene as an example,and combining with the soil environmental site investigation,the residential site planning and the characteristics of the high-rise residential structure,this paper develops the exposure model with residential site planning and building structure by modifying the general exposure model.Then the paper conducts the health risk assessment of the contaminated site respectively by the two exposure models.Next the paper compares the differences of the two exposure models on the health risk level of benzene in soil and remediation target as well as the corresponding soil remediation volume and costs of benzene in soil.The results indicate that the health risk of benzene in soil is significantly higher than the acceptable level which is 1×10^-6,suggesting that the site remediation is necessary;the procedures of the general exposure model is easy to operate,but its results are relatively conservative,which could lead to overrepair of the site.Further more,the exposure model with residential site planning and building structure gives more scientific assessment results than that the general exposure model can do,with the remediation target increasing by about 240 times,the soil remediation volume reducing by about 82.03%and the remediation costs reducing by about 86.87%.Thus the risk assessment exposure models should combine with site planning and the structure characteristics of buildings,so that the assessment results would be more practical and objective.