Research on groundwater mixing between aquifers by isotope technique: A case study in Ca Mau, Nam Bo Plain

• Autorzy: Lam Hoang Quoc Viet , Dao Hong Hai , Nguyen Kien Chinh , Tran Thi Nich Lien , Nguyen Van Phuc , Nguyen Pham Tuong Minh , Duong Thi Ngoc Tuyen

Identyfikatory

DOI

10.29227/IM-2025-01-02-007

• Konferencja: CESD 2024 : Conference on Earth Sciences : November 11th, 2024, Ho Chi Minh City, Vietnam
• Języki publikacji: EN

Abstrakty

EN

Ca Mau is a province in the Mekong Delta with a complex hydrogeological structure, many faults, hydrogeological windows, and non-uniform distribution of aquitards, including many interspersed salt/fresh groundwater lenses, directly or indirectly affecting the recharge and movement of water in aquifers. In addition, the exploitation of groundwater at high density, focusing on only 3 out of 7 existing aquifers, has seriously reduced the groundwater level, strengthening hydraulic relationships and mixing of water sources between aquifers. To clarify the hydraulic relationships as well as the mixing process between aquifers in Ca Mau province, this study investigated and analysed the mixing of water sources between aquifers using isotopic techniques. We analysed 32 groundwater samples for 14C activity, δ18O, and δ2H. Results show that Ca Mau's groundwater is exclusively "Old Groundwater" with no modern recharge. The correlation between 14C activity and sampling depth is weak (r2 = 0.11 for fresh and 0.26 for saline groundwater), indicating complex mixing processes. Two main factors affecting groundwater mixing were identified: the hydrogeological structure and local mixing processes, including mixing with saline water of marine origin and mixing with other freshwater sources due to the strengthening of the hydraulic relationship between aquifers. The spatial distribution map of 14C activity and δ18O in Ca Mau Province indicates areas of intense mixing. This study provides crucial insights for sustainable groundwater management in Ca Mau Province.

Słowa kluczowe

EN

groundwater mixing; hydraulic relationship; dissolved inorganic carbon; groundwater age; groundwater origin

PL

mieszanie wód gruntowych; stosunek hydrauliczny; rozpuszczony węgiel nieorganiczny; wiek wód gruntowych; pochodzenie wód gruntowych

• Wydawca: Polskie Towarzystwo Przeróbki Kopalin
• Czasopismo: Inżynieria Mineralna
• Rocznik: 2025
• Tom: Vol. 2, no. 1
• Strony: art. no. 7
• Opis fizyczny: Bibliogr. 23 poz., rys., tab., wykr.

Twórcy

autor

Lam Hoang Quoc Viet

• Isotope Hydrology Department, Center for Nuclear Technologies, Ho Chi Minh City, Vietnam

autor

Dao Hong Hai

• Faculty of Geology and Petroleum Engineering, Ho Chi Minh City University of Technology (HCMUT), VNU-HCM, Ho Chi Minh City, Vietnam
• Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam

autor

Nguyen Kien Chinh

• Isotope Hydrology Department, Center for Nuclear Technologies, Ho Chi Minh City, Vietnam

autor

Tran Thi Nich Lien

• Isotope Hydrology Department, Center for Nuclear Technologies, Ho Chi Minh City, Vietnam

autor

Nguyen Van Phuc

• Isotope Hydrology Department, Center for Nuclear Technologies, Ho Chi Minh City, Vietnam

autor

Nguyen Pham Tuong Minh

• Isotope Hydrology Department, Center for Nuclear Technologies, Ho Chi Minh City, Vietnam

autor

Duong Thi Ngoc Tuyen

• Department of Natural Resources and Environment of Ca Mau, Ca Mau, Vietnam

Bibliografia

• 1. Nguyen Huu Dung, et al., "The relationship of groundwater and solid minerals with stratigraphic units and geological structures, Report on N-Q Stratigraphic Division and Study of Geological Structure of the Nam Bo Plain," Department of Geology and Mineral Resources of Vietnam, Ho Chi Minh, 2004.
• 2. Le Van Chung, et al., "Results of implementing the project to protect groundwater in large urban area phase II - Ca Mau province," Division for Water Resources Plaining and Investigation for the South of Viet Nam, the Vietnam Ministry of Natural Resources and Environment, Ha Noi, 2021.
• 3. Center for Water Resources Warning and Forecasting, "Newsletter of announcement, forecast and warning on groundwater resources in Ca Mau province," Division for Water Resources Plaining and Investigation for the South of Viet Nam, the Vietnam Ministry of Natural Resources and Environment, Ha Noi, 04/2022.
• 4. Dao Hong Hai, Nguyen Dinh Tu, "Assessing the middle – upper Pleistocene aquifer vulnerability due to the seawater intrusion in Ca Mau peninsula," Science and Technology Development Journal, Vols. Natural Sciences, Vol 2, no. 4, p. 190, 15-10-2018.
• 5. Lien, T.T.B., et al., "Study the Upper Pleistocene groundwater dynamic in the Nambo Plain for sustainable management of groundwater resources by isotope techniques," Radioanal Nucl Chem, Vol. 332, no. https://doi.org/10.1007/s10967-023-09062-5, p. 3559–3570, 2023.
• 6. Nguyen Kien Chinh, et al., "Summary report of Project “Study groundwater dynamics by the isotope hydrological techniques for water," Center for Nuclear technologies, Vietnam Atomic Energy Institute, the Vietnam Ministry of Science and Technology, Ho Chi Minh, 2015-2016.
• 7. Nguyen Viet Ky, "Mechanism of formation of groundwater salinity zones in the northern Tien River region," Ho Chi Minh City University of Technology, Ho Chi Minh, 2003.
• 8. Doan Van Canh, et al., "Groundwater resources in the Mekong Delta: Challenges and solutions," Journal of Water Resources Science and Technology, vol. 14, 2013.
• 9. IAEA Library Cataloguing in Publication, "Isotope methods for dating old groundwater," in Isotope methods for dating old groundwater, Vienna, International Atomic Energy Agency, 2013, pp. 22, 24, 69.
• 10. F. Cornaton, P. Perrochet, "Groundwater age, life expectancy and transit time distributions in advective{dispersive systems:1. Generalized Reservoir Theory.," F. Cornaton ∗, P. Perrochet, pp. 2-4, November 2018.
• 11. M. A. Geyh, "An Overview Of 14C Analysis In The Study Of Groundwater," Radiocarbon, vol. 42, pp. 99-114, 2000.
• 12. IAEA, "Sampling Procedures for Isotope Hydrology," in Water Resource Programme, Vienna, September, 2014..
• 13. TCVN 6663-11:2011, Water Quality - Sampling - Part 11: Guidelines For Groundwater Sampling, Ministry of Science and Technology, 2011.
• 14. P. H. Stuiver M, "Reporting of 14C data.," Radiocarbon, p. 355–363, 1977.
• 15. G. J. Fontes JCh, "Determination of the initial 14C activity of the total dissolved carbon: a review of the existing models and a new approach.," Water Resour Res, vol. 15, pp. 399-413, 1979.
• 16. Penna, et al., "On the reproducibility and repeatability of laser absorption spectroscopy measurements for δ 2H and δ 18O isotopic analysis," Hydrol Earth Syst Sci Discuss, vol. 7, p. 2975–3014, 2010.
• 17. Doan Van Canh, et al., "Study on the formation and groundwater age in the Nam Bo Plain using isotopic techniques," Vietnam Science and Technology, vol. 4(2), pp. 40-45, 2016.
• 18. Chau Tran Vinh, et al., "Study on the formation of groundwater reserves from hydraulic relationships sources in Nam Bo Plain aquifers using isotopic techniques," VNU Journal of Science, vol. 31, no. 3S, pp. 286-294, 2015.
• 19. Zhonghe Pang, et al., "An Isotopic Geoindicator in the Hydrological Cycle," Procedia Earth and Planetary Science, vol. 17, p. 534 – 537, 2017.
• 20. K. Rozanski, M. Gröning. Carbon-14 assay in water samples using benzene synthesis and liquid scintillation spectrometry, 219-228, IAEA-TECDOC 1401, 2002.

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa nr POPUL/SP/0154/2024/02 w ramach programu "Społeczna odpowiedzialność nauki II" - moduł: Popularyzacja nauki i promocja sportu (2026).