Abstract
Extremely acidic groundwaters (EAG; pH < 3) are frequently observed in the Mekong Delta area. This study geochemically investigates the processes for this phenomenon. Forty-two groundwater and eight sediment samples were collected and performed chemical/mineralogical analyses and leaching experiments. Long-term data from 178 wells of National Groundwater Monitoring Network of the Southern Vietnam (NGMS) were also inspected. In the study area, groundwaters are characterized by increasing concentrations of various species such as SO4, Fe, Mn, Al, Pb, Cr, Zn and U at low pH. SO4 (up to 2959 mg/L) and Fe (up to 1679 mg/L) concentrations in the EAG are generally very high. Framboidal pyrite grains are typically observed in the sediment samples taken from the sites where acidic groundwaters were observed. The leaching experiments with those sediments using deionized water derived pH as low as 2.7 and high metal concentrations in the extractants. Heavy metal concentrations were also high in the extractants of pyrite-free sediments when the pH was adjusted to acidic range. Our results suggest that the high metal concentration in the acidic groundwater are closely related with the low pH induced by the pyrite oxidation. This study also shows that the acidic pH of groundwater is in part related with the well installation; that is, well installation chemically disturbs the confined aquifer, which was originally under reducing environments, and triggers the pyrite oxidation.
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References
Appleyard, S., Wong, S., Willis-Jones, B., Angeloni, J., Watkins, R.: Groundwater acidification caused by urban development in Perth, Western Australia: source, distribution, and implications for management. Soil Res. 42(6), 579–585 (2004). doi:10.1071/SR03074
Benison, K.C., Bowen, B.B.: The evolution of end-member continental waters: the origin of acidity in southern Western Australia. GSA Today 25(6), 4–10 (2015). doi:10.1130/GSATG231A.1
Bui, T.-V.: Report on Assessment of Climate Change on Groundwater Resources in Mekong Delta, Proposal of Adaptation Measures. Division for Water Resources Planning and Investigation for the South of Vietnam (DWRPIS) (2014). (in Vietnamese)
Buschmann, J., Berg, M., Stengel, C., Winkel, L., Sampson, M.L., Trang, P.T.K., Viet, P.H.: Contamination of drinking water resources in the Mekong delta floodplains: arsenic and other trace metals pose serious health risks to population. Environ. Int. 34(6), 756–764 (2008). doi:10.1016/j.envint.2007.12.025
Fest, E.P., Temminghoff, E.J., Griffioen, J., Van Der Grift, B., Van Riemsdijk, W.H.: Groundwater chemistry of Al under Dutch sandy soils: effects of land use and depth. Appl. Geochem. 22(7), 1427–1438 (2007). doi:10.1016/j.apgeochem.2007.02.002
Gröger, J., Proske, U., Hanebuth, T.J., Hamer, K.: Cycling of trace metals and rare earth elements (REE) in acid sulfate soils in the Plain of Reeds, Vietnam. Chem. Geol. 288(3), 162–177 (2011). doi:10.1016/j.chemgeo.2011.07.018
Hoang, T.H., Bang, S., Kim, K.W., Nguyen, M.H., Dang, D.M.: Arsenic in groundwater and sediment in the Mekong River delta, Vietnam. Environ. Pollut. 158(8), 2648–2658 (2010). doi:10.1016/j.envpol.2010.05.001
Husson, O., Verburg, P.H., Phung, M.T., Van Mensvoort, M.E.F.: Spatial variability of acid sulphate soils in the Plain of Reeds, Mekong delta, Vietnam. Geoderma 97(1), 1–19 (2000)
Kjøller, C., Postma, D., Larsen, F.: Groundwater acidification and the mobilization of trace metals in a sandy aquifer. Environ. Sci. Technol. 38(10), 2829–2835 (2004). doi:10.1021/es030133v
Kim, K.: Long-term disturbance of ground water chemistry following well installation. Gr. Water 41(6), 780–789 (2003). doi:10.1111/j.1745-6584.2003.tb02419.x
Ngo, M.T., Lee, J.M., Lee, H.A., Woo, N.C.: The sustainability risk of Ho Chi Minh City, Vietnam, due to saltwater intrusion. Geosci. J. 19(3), 547–560 (2015). doi:10.1007/s12303-014-0052-4
Nguyen, H.D., Vu, B.M., Nguyen, H.D.: Hydrogeological map. Identification of Geological units from Neogene to Quaternary and structural geological study in southern plain of Vietnam. Division for Water Resources Planning and Investigation for the South of Vietnam (DWRPIS) (2004). (in Vietnamese)
Nguyen, K.P., Itoi, R.: Source and release mechanism of arsenic in aquifers of the Mekong Delta, Vietnam. J. Contam. Hydrol. 103(1), 58–69 (2009). doi:10.1016/j.jconhyd.2008.09.005
Seibert, S., Atteia, O., Ursula Salmon, S., Siade, A., Douglas, G., Prommer, H.: Identification and quantification of redox and pH buffering processes in a heterogeneous, low carbonate aquifer during managed aquifer recharge. Water Resour. Res. 52(5), 4003–4025 (2016). doi:10.1002/2015WR017802
Verplanck, P.L., Nordstrom, D.K., Bove, D.J., Plumlee, G.S., Runkel, R.L.: Naturally acidic surface and ground waters draining porphyry-related mineralized areas of the Southern Rocky Mountains, Colorado and New Mexico. Appl. Geochem. 24(2), 255–267 (2009). doi:10.1016/j.apgeochem.2008.11.014
Zhang, Y.C., Slomp, C.P., Broers, H.P., Passier, H.F., Van Cappellen, P.: Denitrification coupled to pyrite oxidation and changes in groundwater quality in a shallow sandy aquifer. Geochim. Cosmochim. Acta 73(22), 6716–6726 (2009). doi:10.1016/j.gca.2009.08.026
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Ha, QK., Choi, S., Kim, K. (2018). Processes Causing Strong Acidic Groundwaters in and Around the Mekong Delta Area. In: Tran-Nguyen, HH., Wong, H., Ragueneau, F., Ha-Minh, C. (eds) Proceedings of the 4th Congrès International de Géotechnique - Ouvrages -Structures. CIGOS 2017. Lecture Notes in Civil Engineering , vol 8. Springer, Singapore. https://doi.org/10.1007/978-981-10-6713-6_104
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DOI: https://doi.org/10.1007/978-981-10-6713-6_104
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