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标题：Mobilization of Arsenic in Groundwater in the Southern Hanoi City (Vietnam) as Studied by Isotopic and Related Techniques
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作者：Dang Duc Nhan ; Doan Van Canh ; Pham Quy Nhan 等
期刊名称：Journal of Environmental Protection
印刷版ISSN：2152-2197
电子版ISSN：2152-2219
出版年度：2013
卷号：4
期号：7A
页码：68-74
DOI：10.4236/jep.2013.47A009
出版社：Scientific Research Publishing
摘要：Sixteen samples of surface and groundwater from the most southern part of the Hanoi city (Vietnam) has been taken and analyzed for the soluble major ions, namely Na⁺, K⁺, , Ca²⁺, Mg²⁺, Cl-, , and arsenic as well as molybdenum content along with isotopic composition of deuterium and oxygen (δ²H and δ¹⁸O), tritium activity, and δ¹³C in DIC. The stable isotopic composition of groundwater indicates the water in that area is recharged from the local meteoric and theRed River’s water sources. The mean residence time of the groundwater should be before 60-ies of the past century as its ³H activity ranged from LOD of the analytical technique (0.4 TU) to 2.1 TU only implying that As would not be related to its recent application. The concentrations of As in the water samples is weakly correlated with those of Fe²⁺ (R² = 0.08) but it strongly did with the concentrations of bicarbonate (R² = 0.80). Thus, bicarbonate seems to liberate As adsorbed on hydrous ferric oxides (Hfo) into water through the displacement mechanism. The surface adsorption-desorption of As could be proven by a strong correlation between As and Mo concentrations (R² = 0.77). The bicarbonate formation in groundwater was thought to be, partly, due to the bio-mineralization of natural organic matter (NOM) by bacteria followed by the dissolution of calcite and/or dolomite present in the sediments. Evidence for the NOM bio-mineralization was found in the close relationship between δ¹³C and the concentration of bicarbonate in water. Therefore, the mobilization of As in groundwater of bicarbonate type in the southern part of Hanoi city seems to be not only due to the reductive dissolution of the Hfo but the bicarbonate displacement also should be considered.
关键词：Arsenic Mobilization; Isotopic Technique; Groundwater; Nom Bio-Mineralization; As-Bicarbonate Displacement