典型渔业养殖区汞的地球化学循环机理与健康评估研究：以珠江三角洲养殖区为例

Methylmercury (MeHg) is the most toxic organic mercury compound.It can accumulate in aquatic biota through bioaccmulation and the concentrations become extremely high in higher trophic organisms through biomagnification along food chains. The accumulation of MeHg in aquatic systems continues to pose a threat to fish and other biota, including human beings.Seafood consumption is the most important pathyway for human MeHg exposure. Global fish production from aquaculture has increased rapidly, with the amount almost equals to the captured fish. Thus, the extent of MeHg contamination in aquaculture products affects the oral intake of this toxic chemical compound by local residents. Mercury contamination in the aquatic environment of aquaculture zones is determined by various environmental, chemical, and physical factors. It is commonly recognized that aquaculture activities, such as operations and the use of contaminated feeds, play important roles in determining the extent of MeHg contamination in the aquatic products. In order to safeguard human health,especially the sensitive members of our populaion, such as pregnant mothers and infants,health risk assessments will be conducted, based on oral intake of MeHg through fish consumption. Thus, it is important to investigate the mercury geochemical cycyling in the aquatic environment and MeHg contamination in aquaculture products of Pearl River Delta, which has gone through a rapid industrial development.

甲基汞是一种毒性很强的有机结合态汞，其通过生物富集以及生物放大作用在水生生物体内进行富集，进而对水生生物以及人体造成危害。目前的研究已经证实水产品摄食是人类甲基汞暴露的最主要途径。养殖渔业近年来发展迅猛，养殖水产品供应量已接近野生水产品，因此养殖水产品中汞的含量已成为人类甲基汞摄入的主要来源。而养殖水环境中汞的浓度以及物理化学条件等是影响养殖类水产品汞含量的重要因素。养殖过程中饵料等的添加，会显著改变养殖水环境的物理和化学性质。但是，目前关于养殖区水环境中汞的地球化学循环研究还鲜有报道。为了保护人类健康，特别是保护怀孕妇女和婴幼儿等敏感人群，分析养殖水环境中汞的形态及含量,针对水产品中甲基汞进行健康风险评估，具有重要的科学研究价值和实际指导意义。

海水养殖区水环境中汞的地球化学循环研究是阐明汞污染危害的重要途径，也是保护人类饮食健康的重要依据。本研究通过采集珠江入海口水产养殖区域内海水样品、海底沉积物和生物样品，分析其中汞的赋存形态及其含量的变化，探讨水产养殖中富营养化所造成的汞的生物甲基化效应，深刻揭示了海水养殖区域中汞的地球化学循环以及甲基汞含量升高的内因。研究结果表明，靠近入珠江入海口的海域由于受到工业化污染较为严重，其汞和甲基汞的含量都要明显高于其它区域，海水养殖区内沉积物的汞含量也明显高于非养殖区域，且春季汞污染严重于秋季。海水养殖所产生的富营养化导致的水环境化学参数向有利于汞甲基化的方向转变，汞的非生物甲基化过程受腐殖酸的影响较大，在赤潮藻的作用下，汞的生物甲基化也趋于上升，海水养殖可促进汞的富集及甲基汞的产生。