大气中汞的浓度水平对农作物中甲基汞富集的影响

在高水平大气汞污染和土壤汞污染的双重压力下，我国农作物中汞污染物含量势必上升，导致健康和生态风险增加，因此，有必要开展深入研究，以认识农作物中汞和甲基汞的富集特征、形成机制和不同来源，增进对汞生物地球化学循环过程的理解，为我国汞污染防治提供参考。目前，尚未见有关水稻等植物体中甲基汞直接大气来源的研究报道。本项目拟以水稻和小麦为典型作物，利用开顶气室进行田间原位实验研究，通过控制气室中气态单质汞和甲基汞的浓度，研究农作物各部位甲基汞含量的变化特征和对不同形态大气汞浓度变化的响应，分析和探讨其特征和规律；同时，通过土壤汞添加实验，分析土壤汞含量变化对作物中甲基汞的影响。结合以上研究，评估大气和土壤汞对水稻等农作物中甲基汞的相对贡献；探索水稻等农作物中甲基汞来源的新途径。

The concentration of mercury in crops are certain to increase under the double pressures of high levels of mercury in soil and ambient air in china,and subseqently enhance the risk exposure for humans and ecosysytem. So it is very important to do intensive researches to comprehend the characteristics, formation mechanisms and sources of mercury and methylmercury in crop tissues. This is greatly significant to futher promote understanding of mercury biogeochemistry and provide references for the mercury pollution prevention and control in our country.However,it has not yet been studied and reported on the potential sources of methylmercury from the atmosphere in rice and other crops tissues. In this project rice and wheat are used for experiment, and the field in-situ experiments will perform using open top chambers (OTCs), which can be adjusted the concentrations of gaseous elemental mercury(Hg0) and gaseous methylmercury(GMeHg) in air. The objectives of this project is main focus on the characteristic and response of methylmercury in crop tissues to the variation of Hg0 and GMeHg concentration in OTCs, and explore the new ways for the sources of methylmercury in rice and other crops. Combing the results from the field experiments of cultivation for rice and wheat under different levels of mercuey in soil, the relative contributions of methylmercury in crop tissues from air and soil will be recognite and assess.These will benefit for understanding the health effects from mercury and effectively avoiding or reducing the Hg exposure for humans and ecosystem.