基于Cd同位素示踪的富营养化湖泊中Cd污染源解析及其迁移转化研究

The problem of Cd pollution in lake waters in China has become more and more emerging, which seriously threatens the ecological security of waters and public health. However, the source and contribution rate of Cd pollution as well as the migration and transformation process of Cd in eutrophic lakes, which is clarified to correctly evaluate the ecological risk of Cd, is a problem that has received extensive attention but lacks systematic study. In view of this problem, the present project intends to select the eutrophic western Chaohu Lake as an example, adopt the Cd isotope tracing technique to analyze Cd and its isotopic composition of different pollution sources (soil parent material, industrial wastewater, farmland drainage, etc), water, and sediment, aiming at exploring the distribution characteristics and source apportionment of Cd and its isotopes in lake waters; On basis of the chemical fractionation method, to investigate the temporal and spatial variation as well as the coupling relationship of Cd content and occurrence in water, sediment and plankton samples in different stages of cyanobacterial blooms so as to explore the influence mechanism of cyanobacterial blooms on migration and transformation of Cd among sediment/water-plankton; In combination with carbon and nitrogen isotopes analysis, to explore the enrichment, migration and transformation of Cd in the water-plankton-fish food chain, revealing the bioaccumulation and trophic transfer of Cd in the aquatic food chain. The implementation of this project can provide a scientific basis for effectively identifying the source of Cd pollution and correctly assessing the ecological risk of Cd in lakes, meanwhile provide a reference for other eutrophic and heavy metals polluted lakes.

我国湖泊Cd污染问题日益突出，持续威胁水域生态安全和公众健康。然而，查清湖泊Cd污染来源及其贡献率，明晰Cd在富营养化湖泊中迁移转化过程从而正确评估Cd生态风险，是广泛关注但缺乏系统研究的问题。本项目拟以富营养化湖泊巢湖西半湖为例，采用Cd同位素示踪技术分析不同污染源（土壤母质、工业废水、农田排水等）、水、沉积物中Cd及其同位素组成，探讨Cd及其同位素在湖泊水域中的分布特征和来源解析；运用化学分级提取法分析蓝藻水华不同阶段水、沉积物和浮游生物中Cd含量和形态的时空变化规律和耦合关系，探明蓝藻水华对Cd在沉积物/水-浮游生物间迁移转化的影响机制；结合碳氮同位素分析探究Cd在“水-浮游生物-鲢鳙鱼”食物链中的富集和迁移转化特征，揭示Cd在水生食物链中的积累和传递规律。本项目的开展可为有效识别湖泊中Cd污染来源、正确评估Cd生态风险提供科学依据，为其他富营养化和重金属复合污染湖泊提供借鉴与参考。

我国湖泊Cd污染问题日益突出，持续威胁水域生态安全和公众健康。然而，查清湖泊Cd污染来源，明晰Cd在富营养化湖泊中迁移转化过程从而正确评估Cd生态风险，是广泛关注但缺乏系统研究的问题。本项目分析了合肥市道路灰尘、行道树树叶和树皮中重金属的富集特征，发现了道路灰尘中Cd的富集程度较高；基于Cd同位素解析了巢湖主要入湖河流南淝河沉积物中Cd的来源，结果表明Cd同位素技术可以较好地用于流域中Cd污染源解析，同时进一步丰富了端元物质Cd同位素组成数据库；根据巢湖沉积物中重金属的总量和形态特征，结合Monte Carlo模拟和物种敏感度分布曲线，有效评估了沉积物中重金属的概率生态风险；根据巢湖主要鱼虾类肌肉组织中微量元素和脂肪酸含量和组成特征，完成了食用鱼虾类的效益-风险评估。本项目研究结果可为有效识别流域Cd污染来源，正确评估Cd生态风险提供借鉴与参考。