新型镉中毒地区土壤-植物体系镉来源与人体暴露的镉同位素示踪研究

High cadmium background area in Three Gorges Region was a chronic cadmium poisoning area, and Cd in the environment were influenced by the natural and anthropogenic sources. Source identification of Cd in environment was very important for the pollution prevention and health control. Jianping area in Wushan county of Three Gorges Region was selected as the study area in this project, and the samples of soil, plant, urine and hair were systematically collected. Firstly, the Cd contents of samples were analyzed to reveal the Cd distribution pattern. Afterwards, the Cd stable isotope technique and the isotope mixing model were utilized to reveal the sources and relative portion of different Cd sources in soil and plants in study area, to explore the possibility of Cd isotopic composition in biomarkers indicating the Cd exposure pathway and sources of local residents. The findings of this research are significant for providing scientific basis and guidance of the pollution prevention and health control in high Cd area, and for providing new and in-depth understanding of Cd isotopic theory and the Cd anomaly mechanism of the Yangtze River catchment.

三峡库区高镉地质背景区为新型的镉慢性中毒地区，环境中镉来源受自然源与人为源的交互作用影响，厘定镉的来源及贡献对区域镉污染治理和人体健康防控有着重要意义。本项目拟以三峡库区巫山县建坪高镉地质背景区为研究区，系统采集土壤、植物、人体生物样（尿样与发样）等样品，在分析样品镉分布特征的基础上，利用镉稳定同位素（δ114/110Cd）示踪技术，结合同位素端元混合模型，揭示土壤-植物中镉的来源及其贡献份额，探索生物标记物镉同位素组成指示人体镉暴露途径和来源的可行性。项目研究成果，有望为高镉背景区的镉污染防治和人体健康防控提供科学依据和理论指导，也有望为长江流域突出存在的镉异常形成机理和镉污染防护研究提供理论支撑，并深化镉同位素地球化学理论与应用体系，具有重要的科学指导意义和现实意义。

本项目旨在利用镉稳定同位素技术，针对高镉地质背景区母岩-土壤-植物-人体样品，开展表生环境中镉来源解析、镉的迁移转化与富集机制的研究,阐明镉污染机理，为镉污染防控提供科学依据，丰富和深化镉同位素端元组成体系。项目的主要研究成果包括：（1）阐明富镉母岩中镉的富集与赋存形态特征，为黑色岩系风化释放镉的机理研究提供了依据；（2）阐明风化成土等自然过程中镉的迁移、转化特征，为深入理解高镉地质背景区土壤镉污染机理提供新视角；（3）查明土壤-植物及潜在物源样品中镉的分布、富集和形态特征，为污染防控与人体健康调控提供了依据；（4）揭示了土壤-植物系统镉的富集与迁移特征，为理解土壤-植物系统镉同位素分馏机制提供了信息；（5）探明研究区黑色岩系-土壤镉同位素组成与分馏特征，解析土壤镉的污染来源，丰富了镉同位素端元组成体系；（6）深入讨论和探索了土壤-植物系统与人体生物样的镉同位素组成研究与意义，为下一步研究提供了新思路。