多元同位素示踪研究城市大气颗粒物中重金属污染来源

With the development of urbanization and industrialization, heavy metal pollution induced by human activities in urban atmospheric particulates is becoming more and more serious, which may bring potential threat to human's health and safety. It is essential for the pollution control and the improvement of urban atmospheric quality to find out the sources of heavy metal pollution and to prevent the pollution from the sources. This project takes the urban atmospheric particulate of Quanzhou city, an economic developed and fast urbanized region,as research object. The distribution and speciation of heavy metals and the components of Pb, Sr, Zn, Cd isotopes in different functional zone urban atmospheric particulates and the typical point-end matters during the circumjacent urbanization,and the component characteristics of Pb, Sr, Zn, Cd isotopes in the speciation of some typical samples, will be determined to ascertain the background values of heavy metals and Pb, Sr, Zn,Cd isotopes in the atmospheric particulates of Quanzhou city. The main pollution sources,accumulation,transfer of heavy metals and the contribution of atmospheric heavy metals to the distribution and pollution of heavy metals in soil will be revealed by means of Pb, Sr, Zn, Cd multi-isotope tracing technique, combined with the geochemistry characteristics of interrelated elements in typical samples and the isotope background values. The contribution of diversified sources to the distribution and pollution of heavy metals in the urban atmosphere will be quantificationally discriminated using the binary (anthropogenic and natural sources) mixed models of above mentioned isotopes. The results of this project may provide scientific data for the prevention and control of heavy metal pollution in urban atmosphere.

随着城市化和工业化进程的不断深入，人类活动造成的大气重金属污染日趋严重，对众多生命健康和安全造成威胁。查明城市大气中重金属污染来源，并从源头上加以防治，对实施污染治理、改善城市大气环境质量具有重要意义。项目选择经济较发达、城市化进程较快的泉州市大气颗粒物为研究对象，分析不同功能区大气颗粒物及端元物质中重金属元素含量、赋存形态及总量与形态中Pb、Sr 、Zn、Cd同位素组成特征，确定泉州市大气颗物重金属元素和Pb、Sr、Zn、Cd同位素自然背景值，利用Pb、Sr、Zn、Cd多元同位素结合示踪技术，结合样品中相关元素的地球化学特征和同位素自然背景值，揭示城市各功能区大气颗粒物中重金属污染物的主要来源、积累和迁移规律以及对土壤重金属元素分布、污染的作用与贡献，利用同位素二元（人为来源和自然来源）混合模型定量地判别各污染源对城市大气中重金属元素分布的贡献，为城市大气重金属污染防治提供科学依据。

随着城市化进程的不断深入，由人类活动造成的城市大气重金属污染日趋严重，对众多生命健康和安全造成威胁。查明城市大气中重金属污染来源，并从源头上加以防治，对实施污染治理、改善城市大气环境质量具有重要意义。项目选择城市化进程较快的泉州市、厦门市大气颗粒物作为研究对象，分析城市不同功能区大气降尘及潜在污染源物质中重金属元素含量、赋存形态以及总量与酸可溶相中Pb、Sr同位素组成，确定泉州市、厦门市大气降尘中重金属元素与Pb、Sr同位素组成自然背景值，利用Pb-Sr同位素结合示踪技术，结合重金属元素的地球化学特征和同位素自然背景值，揭示城市各功能区大气降尘中重金属污染物的来源，利用铅同位素三元混合模型定量计算各重金属污染源对城市大气降尘中重金属元素分布的贡献，为城市大气降尘重金属污染防治提供科学依据。主要成果：(1)厦门市不同功能区大气降尘总量铅同位素组成变化范围较大，大气降尘铅来源较复杂。大气降尘酸可溶相铅206Pb/207Pb比值与福建土壤残渣相比值相差较大，酸可溶相206Pb/207Pb比值明显小于总量铅同位素比值，大气降尘铅受到人类活动来源铅的影响较大.（2）厦门市大气降尘铅同位素组成与燃煤和母质层接近，主要铅人为源是燃煤；各功能区酸可溶相铅同位素组成与燃煤较接近，与母质层相差较大。厦门市大气降尘铅主要来自燃煤尘，其次是自然源和汽车尾气排放。燃煤、汽车尾气、自然源对厦门市大气降尘铅的贡献分别是48.57%、31.14%、20.29%。(3)铅同位素二元混合模型计算得到厦门市大气TSP主要受自然来源(土壤扬尘)的影响，平均贡献率为77.03%，人为来源（汽车尾气排放）则贡献了22.97%。(4)厦门市土壤母质层的87Sr/86Sr特征值（0.718826-0.736344）与厦门市大气降尘的87Sr/86Sr特征值（0.708787~0.711089）相差较大，大气降尘中的锶主要受到汽车尾气、燃煤和海洋源的影响.(5)铅同位素三元混合模型计算出泉州市大气降尘中铅来源主要为土壤母质(29.41%~64.00%)、燃煤尘(22.53%~60.48%)和汽车尾气(3.13%~13.47%)；87Sr/86Sr和1/Sr分布图显示降尘中锶来源主要为燃煤尘和汽车尾气.(6)项目标注成果发表学术论文8篇，参加国际会议、国内会议交流论文各1篇，培养博士1名、硕士5名及本科毕业设计10名