基于人体健康模型（IEUBK、ALM）的温岭地区土壤环境铅基准值研究

以浙江温岭市人群(孕妇、儿童)为研究对象,借鉴国际上认可度较高的由美国国家环境保护署开发的综合暴露吸收生物动力学模型(IEUBK)及成人血铅模型(ALM),采用实验室检测、问卷调查、文献查询等多种方式优化模型参数,推导出该区域基于人群健康风险的土壤环境铅基准值分别为180 mg·kg-1(IEUBK)、555.6 mg·kg-1(ALM),低于英美等发达国家不同场地铅土壤环境基准值.同时,对2种模型参数进行蒙特卡罗分析,探讨模型单因子变化对预测结果造成的影响.结果发现,IEUBK模型参数中空气、饮用水2种介质的铅暴露浓度敏感性均为50.8%,ALM模型中育龄妇女血铅含量几何标准差GSD、根据设定目标血铅浓度时保护人群的概率水平取值n等参数均呈负敏感性,且敏感性最高分别为-39.6%、-19.5%.由敏感性分析结果可知,呼吸暴露途径对模型结果的影响较为显著且普遍高于经口暴露,但由于经口暴露累加的消化吸收量较高,对模型的预测结果也造成一定程度的影响.本研究中优化模型参数提高推导结果的灵敏度可使预测结果更为科学、准确,降低其不确定性,可为后期我国污染土壤铅基准值的制定提供理论依据.此外,需要说明的是,模型涉及的人群铅暴露途径受体为美国人群,是否完全适合中国人群尚需要进一步研究.

Lead benchmarks for soil based on human health model (IEUBK and ALM) in Wenling region

In this study, we combine the Integrated Exposure Uptake Biokinetic Model (IEUBK) and the Adult Lead Model (ALM) with the methods of laboratory tests, questionnaires, and documents to determine environment references of Pb in soil based on health risk by the study on the pregnant woman and child in Wenling of Zhejiang Province. The reference values were 180 mg·kg^-1 and 555.6 mg·kg^-1, respectively, lower than the values of Britain and other developed countries. Two kinds of model parameters were analyzed by Monte Carlo to discuss the prediction impact by changes in one factor model. The sensitivity of the lead exposure in air and drinking water of IEUBK model were 50.8%. The maximum probability of geometric standard deviation of women blood lead concentration in AIM model was -39.6%, while the sensitivity value of target blood lead concentration (n) in protection group was -19.5%. Respiratory exposure was the most significant and widespread and its impact was higher than oral exposure according to sensitivity analysis results. However, oral exposure had higher levels of digestion and absorption which caused uncertainties to the model prediction. Optimization of model parameters improved the sensitivity of the prediction results, leading to more scientific and accurate prediction results and less uncertainty. This study provided theoretical basis for the formulation of the reference value of lead in contaminated soil. Moreover, further study is needed to examine the suitability of the results to Chinese people, as the lead exposure receptors in the model are American.