汞的环境生物地球化学研究进展

A Review of Mercury in Environmental Biogeochemistry

汞是毒性极高的全球性环境污染物。即使在极低剂量下,汞对人类和野生动植物都有相当大的毒性,并导致生态系统功能退化和人类健康风险,有关汞及其化合物的环境生物地球化学研究是目前国际上的热点之一。基于近三十年来的相关研究报道,作者阐述了生态环境中汞的分布特征及化学行为、汞的来源及循环、当前汞的暴露及人类健康风险等方面的最新研究动态。同时,指出生态环境中及环境界面间汞的活化、迁移、转化机制研究、人类活动与汞释放间的关系研究以及生态环境中汞的甲基化作用、生物放大作用等过程和交互作用研究等是今后汞的环境生物地球化学领域内的研究重点。

Mercury is a highly toxic trace element that is now present in various environment media and food worldwide. People concerns over mercury pollution have substantially elevated in recent years because new findings indicate that adversely effects may be taking place at lower concentrations than previously thought. Monitoring of this pollution and the circulation of the matter in biosphere is therefore a most important and urgent task. In recent years, many countries have been faced these issues and scientists from multiple disciplines have involved in these study areas. Mercury is adversely affecting both humans and wildlife, especially to the developing nervous system. The toxicity to organisms depends on the chemical form, the amount, the pathway of exposure and the vulnerability of the person exposed. Natural releases due to mobilisation of naturally occurring from the Earth's crust, current anthropogenic releases from the mobilization of mercury impurities and intentional extraction and use of mercury, and re-mobilisation of historic anthropogenic deposited mercury are the main sources of mercury to the biosphere. The available data indicated that mercury is present all over the globe especially in fish and marine mammals in concentrations that adversely affect human beings and wildlife. These levels have led to consumption advisories in a number of countries warning people, especially sensitive subgroups such as pregnant women and young children, to limit or avoid consumption of certain types of fish from various waterbodies. Mercury is probably among the best-studied environmental toxicants. However, in the field of Environmental Biogeochemistry, further researches are need to provide new information to improve understanding of issues relevant to mercury, including its fate and transport, health and environmental impacts, and the role of human activity. The three aspects listed below should not be delayed, namely, understanding of the natural mechanisms affecting the fate of mercury in and between the environmental media, such as mobilization, transformation, transports and intake, understanding of the human conduct in relation to mercury anthropogenic releases, and understanding of methylation, biomagnification, and other interaction of mercury with other chemical and non-chemical stressors on ecological receptors.