大连湾表层沉积物中汞的赋存形态与生物可利用性研究

为了解大连湾沉积物中汞的赋存形态和生物可利用性,对大连湾表层沉积物中总汞(THg)和甲基汞(Me Hg)的含量进行了分析,并采用选择连续提取法对表层沉积物中汞的赋存形态进行了研究,探讨了沉积物中汞的赋存形态与甲基汞的关系。结果表明:大连湾表层沉积物中总汞和甲基汞的平均含量分别为95.1、0.71 ng/g,甲基汞占总汞的比例(甲基化率)为0.76%,与自然背景值相比,沉积物中总汞含量明显受到了人类活动的影响;大连湾表层沉积物中各赋存形态汞比例的平均值由小至大依次为水溶态汞(Hg-w)(3%)胃酸溶解态汞(Hg-h)(10%)硫化物结合态汞(Hg-s)(24%)有机结合态汞(Hg-o)(31%)强络合态汞(Hg-e)(32%),Hg-e、Hg-o和Hg-s为主要存在形态;沉积物中Hg-w、Hg-h和Hg-o与甲基化率呈正相关,显示Hg-w、Hg-h和Hg-o具有较高的生物可利用性。研究表明,采用选择连续提取法进行沉积物中汞赋存形态的研究,对了解沉积物中汞的生物可利用性具有较好的指示意义。

Speciation and bioavailability of mercury in surface sediments of Dalian Bay

Concentrations of total mercury ( THg) and methylmercury ( MeHg) were analyzed, and the speciation of mercury extracted and relationship between the fractions of mercury and methylmercury content were studied in surface sediments in Dalian Bay by a selective sequential extraction method to investigate the speciation and bio-availability of mercury in the sediments of Dalian Bay. The results showed that the average content was found to be 95. 1 ng/g in total mercury and 0. 71 ng/g in methylmercury in the sediments, percent of methylmercury in total mercury level being referred as methylation rate (0. 76%). The concentration of total mercury in the sediments was influenced by human activities compared with the background value. The order of average percentages of Hg in each fraction in the surface sediments was xpressed as water soluble mercury ( Hg-w) (3%)