潮间带海洋沉积物中痕量汞的释放过程及其影响因素研究

Studies on the Releasing Process of Trace Mercury on Intertidal Marine Sediments and Its Influencing Factors

海洋沉积物对重金属污染物的吸附是1种物理吸附过程，在一定的条件下（波浪和潮汐等），吸附于沉积物中的汞可能重新释放出来，对滨海海洋生态环境造成永久性的潜在危害。在对厦门海域汞污染调查的基础上，选择代表性的海洋沉积物进行取样，系统测定潮间带海洋沉积物痕量汞的释放动力学过程，并分析了盐度、pH、温度和振荡频率对释放作用的影响。结果表明，潮间带海洋沉积物中痕量汞的释放动力学符合Ho的二级动力学方程，即随着时间的延续释放速度逐渐降低，沉积物中痕量汞的释放平衡时间约为24h．沉积物痕量汞的释放量随盐度的增加有所减小，随温度和振荡频率的增加而增加；在pH〈7时释放量随pH值的增加而降低．pH〉7时，释放量随pH值的增加而升高。

The adsorption of heavy metals on marine sediments is a physical process. Mercury contaminants adsorbed on marine sediments may release to water again under certain circumstances depending upon waves, tides, and etc., to give rise to persistent detriment to the marine ecosystem. On the basis of an investigation into the mercury contamination of marine sediments in the sea area of Xiamen, representative marine sediments were selectively sampled to measure the process kinetics of trace mercury releasing from the intertidal marine sediments, and the influences of salinity, pH value, temperature and oscillating frequency on the release were studied. The research results have shown that the releasing kinetic curve of trace mercury on intertidal marine sediments belongs to Ho＇s second-order dynamic equation, i.e., the releasing rate gradually decreases as time goes on and the equilibrium period of the release takes about 24 hours. The release of trace mercury from marine sediments declines with the rising salinity, descending temperatures or lowering oscillating frequency. Along with the rise in pH value, the release of trace mercury decreases when pH〈7 or increases when pH 〉7.