T. C. But, “Investigation into the Trend of Arsenic Pollution in Groundwater within Phu Tho Province. Measures to Reduce the Health Risk to the Human Health Due to the Consumption of Water Contaminated with Arsenic,” M.Sc. Thesis, Hanoi University of Mining and Geology, Hanoi, 2006. (in Vietnamese)

has been cited by the following article:

• TITLE: Mobilization of Arsenic in Groundwater in the Southern Hanoi City (Vietnam) as Studied by Isotopic and Related Techniques

  AUTHORS: Dang Duc Nhan, Doan Van Canh, Pham Quy Nhan, Nguyen Thi Thanh Thuy, Dinh Thi Bich Lieu, Vo Thi Anh, Dang Anh Minh

  KEYWORDS: Arsenic Mobilization; Isotopic Technique; Groundwater; Nom Bio-Mineralization; As-Bicarbonate Displacement

  JOURNAL NAME: Journal of Environmental Protection, Vol.4 No.7A, July 17, 2013

  ABSTRACT: 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.