用RBCA和CLEA模型推导土壤中苯并[a]芘的标准值

我国现行土壤环境质量标准中尚未包含苯并a]芘(Ba]P). 分别应用2种国际上认可的RBCA和CLEA模型,获取了土壤中Ba]P的标准值,并对2种模型的计算结果和取值进行了比较. 结果表明,在目标风险水平设定为10~(-5)时,RBCA和CLEA模型计算的住宅用地土壤Ba]P标准值分别为0.83和1.21 mg/kg;工业用地标准值分别为4.10和26.30 mg/kg. 2种模型住宅用地的标准差异不大,且与其他国家的标准水平基本接近;工业用地的标准差异较大,其中RBCA模型的结果更接近于其他国家标准,而CLEA模型的结果则明显偏高. 造成2种模型计算结果差异的原因主要来自于两方面,即模型的方法原理不同导致的暴露量计算差异以及采用的毒理学数据来源不同导致的数据水平差异. 2种模型暴露途径解析的结果均表明,经口摄入和皮肤接触是土壤污染物Ba]P人体暴露的主要途径,而口鼻吸入导致的暴露量很小.

Derivation of Soil Pollutant Standard for Benzo[a]pyrene Using RBCA and CLEA Models

Current soil quality standards in China do not yet include benzoa]pyrene (Ba]P). In this research, soil standards of Ba]P were calculated using two environmental risk assessment models, the Risk-Based Corrective Action (RBCA) model and the Contaminated Land Exposure Assessment (CLEA) model. Calculated results derived by these two models were compared. The results showed that, under the target risk level of 10~(-5), the standard of Ba]P for residential land use derived by the RBCA and CLEA models was 0.83 and 1.21 mg/kg respectively, and the standard for industrial land use was 4.10 and 26.30 mg/kg respectively. For residential land use, the calculated standards by the two models were close to each other and also close to the standards of other countries. However, for industrial land use, significant difference existed between the calculated standards from the two models. The results of the RBCA model were close to the standard levels of other countries, while the results of CLEA were significantly higher. The difference in the results from these two models was in two main aspects: one was the difference of exposure assessment led by different principles and algorithms of the two models, and the other was the difference in source and data level adopted in Ba]P toxicology data. Both results of the two models showed that oral ingestion and dermal exposure pathways were the main ways by which the human body was exposed to Ba]P in soil, and the exposure caused by the inhalation pathway was small.