Mobilization of Arsenic in Groundwater in the Southern Hanoi City (Vietnam) as Studied by Isotopic and Related Techniques
- 1 Vietnam Atomic Energy Institute, Hanoi, Vietnam
- 2 Vietnam Association of Hydrogeology, Hanoi, Vietnam
- 3 Center for Water Resources Management, Hanoi, Vietnam
- 4 Hanoi University of Mining and Geology, Hanoi, Vietnam
- 5 Institute for Nuclear Science and Technology, Hanoi, Vietnam
- 6 Institute for Nuclear Science and Technology, Hanoi, Vietnam
- 7 Institute for Nuclear Science and Technology, Hanoi, Vietnam
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 + , , Ca 2+ , Mg 2+ , Cl - , , and arsenic as well as molybdenum content along with isotopic composition of deuterium and oxygen ( δ 2 H and δ 18 O), tritium activity, and δ 13 C 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 3 H 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 Fe 2+ (R 2 = 0.08) but it strongly did with the concentrations of bicarbonate (R 2 = 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 (R 2 = 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 δ 13 C 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.
- M. Berg, H. C. Tran, T. C. Nguyen, H. V. Pham, R. Schetenleib and W. Riger, “Arsenic Contamination of Groundwater and Drinking Water in Vietnam: A Human Health Threat,” Environmental Science and Technology, Vol. 35, No. 13, 2001, pp. 2621-2626. doi:10.1021/es010027y
- P. K. Quoc, “Investigation into the Sources and Distribution of Arsenic in the Holocene Aquifer in the Ha Nam Province, Vietnam,” M.Sc. Thesis, Hanoi University of Mining and Geology, Hanoi, 2006. (in Vietnamese)
- 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)
- T. Agusa , T. Kunito , J. Fujihara , T. B. Minh, P. T. K. Trang, H. Itawa, A. Subramanian, P. H. Viet and S. Tanabe, “Contamination by Arsenic and Other Trace Elements in Tube-Wells Water and Its Risk Assessment to Human in Hanoi, Vietnam,” Environmental Pollution, Vol. 139, No. 2, 2006, pp. 330-339.
- S. Luzi, M. Berg, P. T. T. Trang, B. H. Nhat and P. H. Viet, “A Sand Filtration Solution for the Arsenic Removal from Tube-Well Groundwater at the Family Scale,” Proceeding of the 3rd Conference of Science and Technology for the Environment and Sustainable Development, Hanoi University of Natural Sciences Press, Hanoi, 2004, pp. 52-55.
- C. T. Ha , L. V. Chieu , D. V. Ve , V. N. Duy , T. P. Lai, M. Berg and U. von Gunten, “Arsenic Removal from Groundwater by Iron Co-precipitation in Contact Filter,” Proceeding of the 3rd Conference of Science and Technology for the Environment and Sustainable Development, Hanoi University of Natural Sciences Press, Hanoi, 2004, pp. 56-59.
- D. V. Binh, “The Formation and Distribution Trend of Arsenic in Groundwater of the Quaternary Aquifers. Measures for Reducing the Risk of the Arsenic Contamination to the Water Quality,” Ph.D. Thesis, Hanoi University of Mining and Geology, Hanoi, 2007.
- P. L. Smedly and D. G. Kinniburgh, “A Review of the Sources, Behaviour and Distribution of Arsenic in Natural Water,” Applied Geochemistry, Vol. 17, No. 5, 2002, pp. 517-568. doi:10.1016/S0883-2927(02)00018-5
- P. Ravencroft, J. M. McArthur and B. A. Hoque, “Geochemical and Paleohydrological Controls on Pollution of Groundwater by Arsenic,” In: W. R. Chappell, Ed., Arsenic Exposure and Health Effect IV, Elsevier, Amsterdam, 2001.
- J. M. McArthur, P. Ravencroft and M. F. Thirlwall, “Arsenic in Groundwater: Testing Pollution Mechanisms for Sedimentary Aquifers in Bangladesh,” Water Resources Research, Vol. 37, No. 1, 2001, pp. 109-117. doi:10.1029/2000WR900270