污染场地土壤多环芳烃（PAHs）生物可利用浓度的健康风险评价方法

随土壤不慎经口摄入是PAHs对人体健康造成危害的重要途径之一,目前该暴露途径下PAHs的健康风险计算主要基于土壤中总PAHs浓度进行计算。但是,这种计算方法并未考虑PAHs在土壤中的赋存状态及经口摄入后在人体不同器官中的毒理动力学过程,导致计算结果过于保守,修复目标过于严格,修复成本过高。针对这一问题国外相关研究人员已开展基于土壤中PAHs生物可利用性的健康风险评价研究并取得较大进展,但在国内就如何在风险评价过程中引入PAHs生物可利用性及其面临的障碍缺乏系统性报道。在对土壤中PAHs赋存形态及其随土壤经口腔摄入后在人体消化及循环系统中的动态分配最新研究成果进行综述的基础上,通过对该暴露途径下现有风险计算模型存在问题及原因进行分析,提出基于土壤中PAHs可利用浓度进行风险计算,并对相应计算模型进行推导以及模型参数的获取方法进行了简要概括,以解决目前模型计算结果过于保守的问题。同时,对于在现有分层次进行场地健康风险评价思路中如何科学地纳入基于土壤中PAHs可利用浓度进行风险计算的思路以及在实际风险评价中应用该思路还需进行的研究工作进行了简要讨论。

Health risk assessment based on the bioaccessibile concentration of PAHs in soil

Incidental ingestion of contaminated soil through oral is one of the important pathways by which PAHs can cause adverse health effect to human beings.Currently,the risk is calculated based on the total concentration of PAHs in soil without consideration of effects of different forms of PAHs and the toxicological dynamics in different organs after contaminated soil is ingested,which is obviously too conservative.Many attempts have been made and reported abroad to improve the risk assessment based on the bioaccessible PAHs in soil.In the paper,the latest advances in the research on the form and distribution of PAHs in soil and its dynamic partition in the gastrointestinal tract,as well as the circulation system,are reviewed,and the reasons contributing to the conservativeness of the current model is analyzed and the perspective that taking the bioaccessible concentration of PAHs in soil as the benchmark concentration for risk assessment under the oral ingestion pathway is proposed,with the purpose being to overcome the conservative issue inherent in the current risk calculation approach.Further,the risk calculation model based on bioaccessible concentration of PAHs in soil is derived,followed by the discussion on how the perspective should be embedded into the tiered approach in site risk assessment and the work that should be accomplished for the implementation of the perspective in practical assessment work scientifically.