江苏省化工企业污染场地中持久性有机物的生物/人体有效性研究及环境风险评价

Persistent organic pollutants (POPs) in urban industrial lands are an emerging environmental concern in China during the recent process of upgrade of industrial structure. Soil risk assessments are based on total not the bioavailable concentrations of POPs, which overestimate risk and lead to unnecessary remediation of the contaminated soil. In this proposal, the main POPs in soils, where former chemical plants were located in Jiangsu Province,will be investigated. Several biomimetic approaches, used to measure the biological availability of POPs, will be compared with earthworm bioaccumulation to test how well the approaches can be used in the impacted soil. For the oral bioavailability of POPs, several in vitro gastrointestinal methods will be validated by correlating with in vivo test and improved by adjusting some parameters. Models based on the biomimetic approaches as well as the in vitro gastrointestinal methods will be developed to predict the bioavailability of POP. The risk assessment of former chemical plant-impacted soils will be performed based on the in vivo tests, in vitro tests, and models.

我国产业结构调整中大量化工企业关闭或搬迁。遗留的污染场地中的持久性有机污染物导致不容忽视的生态和人体健康风险。以有机污染物总浓度为基准的风险评价会导致不准确的结果和修复过程的极大浪费。本项目以持久性有机物的生物/人体有效性为切入点，以江苏省典型化工企业污染场地中的主要有机污染物为研究目标。通过与陆生软体动物富集实验相耦合及比较研究，确定适用于化工污染场地的仿生学技术，并建立预测有机污染物生物有效性的模型，开展生态风险评价。通过与小鼠活体实验的线性回归，修正并确定适用于化工企业污染土壤的胃肠模拟液体外法。结合土壤性质，以体外模拟法为基础建立预测有机污染物人体有效性的模型，开展人体健康风险评价。通过生态和人体健康风险研究，综合评价江苏省化工企业污染场地的环境风险，为我国化工企业污染土壤的修复指标的建立提供理论依据和技术支持。

项目采集江苏省，浙江省，湖北省以及澳大利亚等地的场地污染土壤，以有机氯农药和多环芳烃为目标开展研究。通过提取-净化，GC-MS分析测定了土壤中有机氯农药和多环芳烃的污染程度；通过同系物比例法追溯了污染物来源。通过预实验和文献查阅，确定了6小时Tenax提取为经济快捷的仿生学手段，研究有机氯农药和多环芳烃在土壤中的物化有效性。项目着重于人体健康方面-人体生物有效性的研究。针对目前胃肠模拟体外方法不能模拟实际人体肠道的动态吸收过程进而低估了疏水性有机污染物的人体生物有效性这样一个难题，该项目首次尝试在现有的胃肠模拟方法中添加Tenax吸附池材料用以模仿人体肠道吸收的动态过程。通过与小鼠活体结果相校正，Tenax改进的胃肠模拟方法可以很好的预测土壤中滴滴涕的人体生物有效性。此外有机氯农药和多环芳烃的人体生物有效性与土壤中黑碳含量成显著负相关。一些场地虽然污染程度高，但是因为黑碳含量也很高，一定程度上降低了污染物的人体生物有效性，也降低其潜在的人体健康风险。由于黑碳可降低污染物的人体生物有效性和健康风险，因此黑碳也具有一定的土壤修复潜能。