我国红树林主要分布区表层沉积物砷的分布及形态特征

Distribution Features and Speciation of Heavy Metals in Surface Sediments of Main Mangrove of China

利用ICP-MS分析了我国红树林主要分布区表层沉积物的As含量和形态,阐明As的分布及其形态特征.结果表明,表层沉积物中w(As)为3.14～19.16mg/g,平均值为8.14mg/g.表层沉积物中w(As)与w(Fe),w(Mn),pH,w(有机质),粉粒和黏粒所占比例呈显著或极显著正相关.表层沉积物中的As主要以残渣态存在,其次为有机质-硫化物结合态.在整个研究区域,As的5种形态在总量中的所占比例:可交换离子态为14.40%,碳酸盐结合态为1.41%,铁锰氧化物结合态为2.16%,有机质-硫化物结合态为30.40%,残渣态为50.65%.可交换离子态所占比例与w(有机质)和pH呈极显著正相关.有机质-硫化物结合态所占比例与盐度、黏粒和粉粒所占比例呈显著或极显著正相关.残渣态所占比例与盐度、粉粒和黏粒所占比例呈极显著正相关.

Arsenic contents in surface sediments collected from mangrove were analyzed with a PE DRC-e ICP-MS, and the distribution and species of As were identified.The results showed that As content ranged from 3.14- 19.16 mg/g, with an average content of 8.14 mg/g. As content correlated well and positively with the contents of Fe and Mn, pH, organic content, silt and clay i Residual As was the primary species, and organic and sulfide As were the secondary species in the surface sediments. Among five As species, the exchangeable As accounted for 14.40% , carbonate As accounted for 1.41 % , Fc-Mn oxides As accounted for 2.16% , organic-sulphide As accounted for 30.40% , and residual As accounted for 50.65 % . Exchangeable As positively correlated with organic content and pH significantly. Organic-sulfide As and residual As positively correlated with salinity, silt and clay significantly.