我国红树林主要分布区表层沉积物砷的分布及形态特征

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3.14～19.16 mg/g，平均值为8.14 mg/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. 

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

Arsenic contents in surface sediments collected from mangrove were analyzed witha PE DRC-e ICP-MS, and the distribution and species of As were identified.Theresults 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.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%, Fe-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, siltand clay significantly.