珠江广州河段底泥中砷的形态分析

对底泥中4种结合态的几种形态砷(As(Ⅲ)、As(Ⅴ)、甲基胂酸盐和二甲基胂酸盐)的测定表明,底泥中砷的污染严重,平均为41.7ppm.酸溶解态、碱溶解态和残渣态含砷量分别占72.4%、8.8%和18.9%,水溶态含砷量为全砷量的千分之几(ppb级).各结合态中都以无机砷为主,As(Ⅲ)占多数,占总砷量1/2以上;有机砷占总砷量1/2左右,以二甲基胂酸盐为主.

Study of Arsenic Species in Sediment in Guangzhou Section of Pearl River

According to their characteristics, arsenic in sediment was classified into four states: water soluble, HCl-extracting, NaOH-extracting and residue. Four arsenic species, i.e. inorganic arsenic As(III) and As(V) and organic arsenic monomethyl arsonate and dimethyl arsonate (DMA) in sediment were analyzed by spectrophotometry after solvent extraction.The results show that there are some rules for the arsenic in sediment. Arsenic concentration for all sampling sites is affected by pollutiou source around that. Arsenic concentration of HCl-extracting state is the highest in the sediment. In HCl-extracting and NaOH-extracting states, inorganic arsenic species is higher than organic arsenic, As(III) is predominant, and DMA is the major organic species.