中文摘要：

重金属污染对环境和人体健康已造成严重威胁,N-亚硝基二甲胺（NDMA）作为具有强致癌性的环境污染物也引起了广泛的关注.本论文探讨了重金属离子Cd（Ⅱ）、Hg（Ⅱ）和Pb（Ⅱ）在模拟胃液中,对NDMA形成的影响;并运用密度泛函理论（DFT）计算方法研究了重金属离子的可能作用机理.实验研究中发现3种重金属离子均能促进NDMA的形成,而理论计算结果表明重金属离子与二甲胺之间的相互作用强于与亚硝酸之间的相互作用,而且重金属离子与二甲胺形成的中间体通过先失去氢质子,再与亚硝酸作用可以生成NDMA.此反应是一个放热过程,而且反应的能垒较低,由此推测重金属离子很可能是通过与二甲胺作用而促进NDMA的形成.

英文摘要：

Heavy metal ion contamination has caused severe threats to environment and human body. NNitrosodimethylamine（ NDMA）,as a potent carcinogen,has drawn much attention. In the present study,the influence of heavy metal ions including Cd（ Ⅱ）,Hg（ Ⅱ）,and Pb（ Ⅱ） on NDMA formation in simulated gastric fluid and the possible reaction mechanisms were investigated from both experimental and theoretical aspects. The experimental results indicate that NDMA formation can be promoted by above heavy metal ions. DFT calculations indicate that there are much stronger interaction of heavy metal ions with dimethylamine（ DMA） than those of heavy meal ions with nitrite. Moreover,the intermediates of heavy metal ions with DMA can first release a proton,and then react with nitrous acid to form NDMA. This reaction is an exothermal process and its energy barrier is relatively low,from which it can be predicted that heavy metal ions are bound to react with DMA to facilitate the formation of NDMA.