基于人体血铅指标的区域土壤环境铅基准值

由于铅对儿童的强烈神经毒性且土壤铅已经成为儿童铅暴露的主要来源,土壤环境铅基准一般基于儿童血铅含量的方法制定.收集国内现有资料,总结并确定出符合我国实际的关键参数取值范围,其中空气、饮水中铅含量分别在0.12~1.0μg.m-3、2~10μg.L-1之间;0~6岁儿童饮食暴露途径铅摄入量约10~25μg.d-1;育龄妇女血铅几何均值4.79μg.dL-1,标准差1.48.采用国际上认可度较高的综合暴露吸收生物动力学模型(IEUBK)和成人血铅模型(ALM),计算我国居住用地和工业/商业用地土壤环境铅基准值分别为282 mg.kg-1和627 mg.kg-1,略低于英美等国.参数敏感性分析表明,我国儿童平均铅暴露量明显高于发达国家且暴露场景与欧美发达国家有明显不同.我国亟需开展环境铅暴露与儿童血铅含量相互关系研究,制定基于血铅指标的铅污染土壤风险评估方法导则.

Development of Lead Benchmarks for Soil Based on Human Blood Lead Level in China

Lead benchmarks for soil are mainly established based on blood lead concentration of children. This is because lead plays a dramatically negative role in children's cognitive development and intellectual performance and thus soil lead has been concerned as main lead exposure source for children. Based on the extensively collection of domestic available data, lead levels in air, drinking water are 0.12-1.0 μg·m~(-3) and 2-10 μg·L~(-1);ingestion of lead from food by children of 0-6 years old is 10-25 μg·d~(-1);geometric mean of women blood lead concentration of child bearing age is 4.79 μg·dL~-1,with 1.48 GSD. Lead benchmarks for soil were calculated with the Integration Exposure Uptake Biokinetic Model (IEUBK) and the Adult Lead Model (ALM).The results showed the lead criteria values for residual land and commercial/industrial land was 282 mg·kg~(-1) and 627 mg·kg~(-1) respectively, which was slighfly lower compared with USA and UK. Parameters sensitivity analysis indicated that lead exposure scenario of children in China was significantly different from children in developed countries and children lead exposure level in China was obviously higher. Urgent work is required for the relationship studies between lead exposure scenario and blood lead level of children and establishment of risk assessment guideline of lead contaminated soil based on human blood lead level.