重金属对多溴联苯醚在农田-蔬菜体系中迁移归趋的影响机制和模型预测

The pollution of polybrominated diphenyl ethers (PBDEs) in the electroinc-waste recycling site has raised great environmental and health concerns. It has been found that heavy metal could promote the uptake of PBDEs in plant, however, current studies of the fate and transportation of PBDEs in the soil-plant system usually overlook the effect of heavy metals, which may greatly underestimate the bioaccumulation of PBDEs in plant. Given the combined contamination of PBDEs and heavy metals in the electroinc-waste recycling site, in this proposal, BDE-47 , BDE-153, and BDE-209 and heavy metals of Cu and Cd were selected, as well as the agricultural soil around the electronic-waste site of Qingyuan, Guangdong. Complementary chemical, instrumental, and modeling methods will be used. The effects and mechanisms of PBDEs sorption on the agricultural soil and uptake by lettuce following heavy metal exposure will be studied. A mechanistic model will be developed to predict the transportation of PBDEs in the agricultural soil-vegetable system under the effect of heavy metals. This project cosiders the complex and combined-polluted condition in the electronic-waste disposal site. Additionally, comprehensive methods and technologies will be employed to elucidate the mechanisms. Moreover, the model developed in this project can predict the bioconcentration of PBDEs in vegetables in the present of heavy metals. This project will improve our understanding of the environmental behaviors of PBDEs in the electronic-waste site, and provide guidelines to the risk assessment and baseline development of PBDEs.

电子垃圾拆解区的多溴联苯醚（PBDEs）污染引起了严重的环境和健康问题。研究表明重金属能促进有机物的植物吸收，然而目前对PBDEs在土壤-植物系统的迁移研究往往忽略重金属的影响，可能大大低估PBDEs的植物积累。本项目从拆解区PBDEs和重金属复合污染的实际出发，具体以BDE-47、BDE-153、BDE-209和铜镉为研究对象，选取广东清远拆解区附近农田土壤和生菜为介质，结合实验、仪器表征以及机理模型，研究重金属对农田土吸附和生菜吸收PBDEs的影响机制，构建预测PBDEs在重金属污染农田-蔬菜迁移归趋的机理模型。项目切合电子垃圾拆解区复合污染的实际，多手段实现机理探究，构建的机理模型适用于预测重金属污染农田的PBDEs蔬菜富集浓度。本项目将提高对电子垃圾污染区PBDEs环境行为的认识，为评价PBDEs对生态环境和食物链潜在暴露风险提供理论依据，对PBDEs环境基准建立具有重要意义。

电子垃圾的安全处置是一个世界性难题，不当的回收和处置导致了大量的多溴联苯醚（PBEDs）以及有毒有害重金属（如铅、铜、镉等）进入环境。PBEDs作为持久性有毒有机污染物，具有内分泌干扰效应、神经毒性、生殖毒性和致癌性。PBDEs在关键环境介质中的迁移归趋是评价其环境风险和对其进行环境修复工作的关键。然而，污染场地及其附近农田土壤存在一定程度的重金属复合污染，但重金属共存对PBDEs迁移归趋的影响研究仍有待深入。本项目结合实验、先进仪器表征和数学模型，从机理层面理解共存重金属的影响，分析PBDEs在土壤和蔬菜的迁移和环境归趋，定量评估PBDEs在土壤和植物的生物有效性，为电子垃圾污染区PBDEs的生态风险和食品安全评价提供理论依据。研究成果主要包括以下几方面：1）理解土壤特性对重金属吸附和释放的影响，并建立相关的机理预测模型；2）探究典型重金属对PBDEs在蔬菜中迁移和吸收的影响和机制；3）构建PBDEs在土壤中吸附和植物吸收的机理模型。成果阐明了实际污染土壤中重金属释放的控制因素，建立了重金属铜释放的动力学模型，构建了土壤有机质组成与重金属络合能力的定量关系；揭示了不同重金属污染浓度下，蔬菜生长和生理指标等的变化以及重金属和PBDEs在蔬菜不同部分的富集；定量预测了常见有机污染物和PBDEs在土壤的吸附和在不同植物中的富集浓度。本研究将提高对PBDEs在土壤和植物体系迁移归趋的认识，对评价PBDEs的生态风险及其对食物链的潜在暴露风险具有重要意义，为PBDEs的土壤污染控制和修复提供基础信息。