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Larsen F, Van Hoang H, Tran LV, Pham NQ. Paleo-climatic control on recharge and fresh-salt groundwater distribution in the Red River delta plain, Vietnam. Sci Rep 2024; 14:21280. [PMID: 39261523 PMCID: PMC11391079 DOI: 10.1038/s41598-024-71899-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 09/02/2024] [Indexed: 09/13/2024] Open
Abstract
Paleo-climatic induced sedimentation controls present-day recharge and the fresh-salt groundwater distribution in Quaternary delta systems. During sea-level highstands, marine clays with saline pore water were deposited and are interbedded with aquifers of coarse-grained sandy fluvial and shallow marine deposits, laid down during lowstands. The low-permeable marine layers may inhibit recent recharge to deeper aquifers, and thereby limit sustainable use of these freshwater resources. This phenomenon has been investigated in the Red River delta plain, using geophysical borehole logging, transient electromagnetic soundings, groundwater chemistry, stable isotope analysis and 3H and 14C dating of groundwater. Results reveal that marine saline pore water is still present in the Holocene marine clays, implying that fresh water has not entered the clays since their deposition. Therefore, recharge within the delta plain is not occurring and the deeper aquifers are hydraulically disconnected from the upper sandy layers. Today, recharge only occurs from the hinterland. Recharge during the last glacial period has flushed saline pore water from Pleistocene marine clays, but these clays were again affected by saline water during the Holocene transgression. The use of the groundwater resources in the delta plain must be adjusted to the present recharge to be sustainable.
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Affiliation(s)
- Flemming Larsen
- Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350, Copenhagen, Denmark.
| | - Hoan Van Hoang
- National Center for Water Resources Planning and Investigation, Long Bien District, Sai Dong Ward, 1000, Hanoi, Vietnam
| | - Long Vu Tran
- Department of Hydrogeology, Hanoi University of Mining and Geology, Hanoi, Vietnam
| | - Nhan Quy Pham
- Hanoi University of Natural Resources and Environment, Hanoi, Vietnam
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2
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Jasechko S, Seybold H, Perrone D, Fan Y, Shamsudduha M, Taylor RG, Fallatah O, Kirchner JW. Rapid groundwater decline and some cases of recovery in aquifers globally. Nature 2024; 625:715-721. [PMID: 38267682 PMCID: PMC10808077 DOI: 10.1038/s41586-023-06879-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 11/14/2023] [Indexed: 01/26/2024]
Abstract
Groundwater resources are vital to ecosystems and livelihoods. Excessive groundwater withdrawals can cause groundwater levels to decline1-10, resulting in seawater intrusion11, land subsidence12,13, streamflow depletion14-16 and wells running dry17. However, the global pace and prevalence of local groundwater declines are poorly constrained, because in situ groundwater levels have not been synthesized at the global scale. Here we analyse in situ groundwater-level trends for 170,000 monitoring wells and 1,693 aquifer systems in countries that encompass approximately 75% of global groundwater withdrawals18. We show that rapid groundwater-level declines (>0.5 m year-1) are widespread in the twenty-first century, especially in dry regions with extensive croplands. Critically, we also show that groundwater-level declines have accelerated over the past four decades in 30% of the world's regional aquifers. This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion. Our analysis also reveals specific cases in which depletion trends have reversed following policy changes, managed aquifer recharge and surface-water diversions, demonstrating the potential for depleted aquifer systems to recover.
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Affiliation(s)
- Scott Jasechko
- Bren School of Environmental Science & Management, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Hansjörg Seybold
- Department of Environmental Systems Sciences, ETH Zürich, Zürich, Switzerland
| | - Debra Perrone
- Environmental Studies Program, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Ying Fan
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Mohammad Shamsudduha
- Institute for Risk and Disaster Reduction, University College London, London, UK
| | | | - Othman Fallatah
- Department of Nuclear Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
- Center for Training and Radiation Protection, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - James W Kirchner
- Department of Environmental Systems Sciences, ETH Zürich, Zürich, Switzerland
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
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3
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An Integrated Approach for Investigating the Salinity Evolution in a Mediterranean Coastal Karst Aquifer. WATER 2022. [DOI: 10.3390/w14111725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Coastal areas are characterized by considerable demographic pressure that generally leads to groundwater overexploitation. In the Mediterranean region, this situation is exacerbated by a recharge reduction enhanced by climate change. The consequence is water table drawdown that alters the freshwater/seawater interface facilitating seawater intrusion. However, the groundwater salinity may also be affected by other natural/anthropogenic sources. In this paper, water quality data gathered at 47 private and public wells in a coastal karst aquifer in Apulia (southern Italy), were interpreted by applying disparate methods to reveal the different sources of groundwater salinity. Chemical characterization, multivariate statistical analysis, and mixing calculations supplied the groundwater salinization degree. Characteristic ion ratios, strontium isotope (87Sr/86Sr), and pure mixing modelling identified the current seawater intrusion as a main salinity source, also highlighting the contribution of water–rock interaction to groundwater composition and excluding influence from Cretaceous paleo-seawater. Only the combined approach of all the methodologies allowed a clear identification of the main sources of salinization, excluding other less probable ones (e.g., paleo-seawater). The proposed approach enables effective investigation of processes governing salinity changes in coastal aquifers, to support more informed management.
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Yang F, Liu S, Jia C, Wang Y. Identification of groundwater microbial communities and their connection to the hydrochemical environment in southern Laizhou Bay, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:14263-14278. [PMID: 34608579 DOI: 10.1007/s11356-021-16812-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
The microbial community plays an important role in the biogeochemical cycle in coastal groundwater ecosystems. However, the composition and controlling factors of the microbial community in coastal closed groundwater systems (CCGSs) with high salinity have rarely been studied. Here, we investigated and analyzed the hydrochemical characteristics and microbial community composition of seven brine samples with high total dissolved solid (TDS) values ranging from 74.5 to 132.3 g/L within and across three coastal saltworks (Yangkou, Hanting, and Changyi) in southern Laizhou Bay (SLB). The bacterial diversity was independent of salinity. Compared with those of low-salinity groundwater, the diversity of the microbial community in brine was lower, but the richness was slightly higher. There was a significant correlation between the microbial community diversity and groundwater sources, which indicated that the microbial communities were affected by groundwater sources. A comparison of the microbial community compositions of the three saltworks showed that the Hanting and Changyi saltworks had similar microbial communities due to their similar sampling depths. In addition, the main force shaping the differences in the microbial communities in both coastal open groundwater systems (COGSs) and CCGSs was identified as the hydraulic connection with the seawater controlled by hydrogeological conditions formed throughout geological history. This study can help to elucidate the biogeochemical processes in coastal aquifers.
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Affiliation(s)
- Fan Yang
- Institute of Marine Science and Technology, Shandong University, Binhai Road No. 72, Qingdao, 266237, Shandong, China
| | - Sen Liu
- Institute of Marine Science and Technology, Shandong University, Binhai Road No. 72, Qingdao, 266237, Shandong, China.
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.
| | - Chao Jia
- Institute of Marine Science and Technology, Shandong University, Binhai Road No. 72, Qingdao, 266237, Shandong, China.
| | - Yujue Wang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China
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Ez-Zaouy Y, Bouchaou L, Saad A, Hssaisoune M, Brouziyne Y, Dhiba D, Chehbouni A. Morocco's coastal aquifers: Recent observations, evolution and perspectives towards sustainability. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 293:118498. [PMID: 34798220 DOI: 10.1016/j.envpol.2021.118498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 10/29/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
During the last decades, the coastal areas of Morocco have witnessed an intense socioeconomic development associated with a continuous population growth and urban extension. This has led to an overexploitation of coastal aquifers leading to a degradation of their water quality. In order to obtain large scale overview on the quality status of Morocco's coastal aquifers (MCA) to assist national water managers to make informed decisions, a comprehensive scrutinization of the MCA against common indicators and using unified methods is essential. In this study, databases from thirteen MCA were analyzed, using multivariate statistical approaches and graphical methods in order to investigate the degree of mineralization in each aquifer and to identify the main salinization processes prevailing in groundwater. The results showed that the dominant groundwater types are Na-Cl, Ca-Mg-Cl, Ca-Mg-SO4, Ca-Mg-HCO3 and Ca-HCO3-Cl. The Gibbs diagram and the seawater contribution (0-37%) indicate that the mineralization is mainly due to the seawater intrusion and water-rock interaction. The salinity degree diagram illustrates that almost all groundwater samples are located in the moderate to very saline zone, indicating that MCA are recharged by water from variable sources. The groundwater quality assessment shows a deterioration, particularly by seawater intrusion and significant nitrate pollution. The temporal evolution confirm that the MCA are influenced by seawater namely in the Atlantic part. The Wilcox and USSL diagram indicate that the majority of sampled water are unsuitable for irrigation uses. In addition, and by referring to the WHO and the Moroccan standards for water potability, large number of samples from the groundwaters of the MCA is not fully adequate for drinking purposes. A set of management actions (e,g., artificial recharge) are proposed in order to mitigate the effect of groundwater overexploitation and seawater intrusion to ensure the sustainability of MCA.
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Affiliation(s)
- Yassine Ez-Zaouy
- Mohammed VI Polytechnic University (UM6P), International Water Research Institute, Ben Guerir, 43150, Morocco.
| | - Lhoussaine Bouchaou
- Mohammed VI Polytechnic University (UM6P), International Water Research Institute, Ben Guerir, 43150, Morocco; Laboratory of Applied Geology and Geo-Environment, Ibn Zohr University, Agadir, 80035, Morocco
| | - Aicha Saad
- Polydisciplinary Faculty of Taroudant, Exploration and Management of Natural and Environmental Resources Team (EGERNE) Taroudant, Ibn Zohr University, Agadir, 80035, Morocco
| | - Mohammed Hssaisoune
- Laboratory of Applied Geology and Geo-Environment, Ibn Zohr University, Agadir, 80035, Morocco; Faculty of Applied Sciences, Ibn Zohr University, B.O. 6146 Azrou District, 86153, Ait Melloul, Morocco
| | - Youssef Brouziyne
- Mohammed VI Polytechnic University (UM6P), International Water Research Institute, Ben Guerir, 43150, Morocco
| | - Driss Dhiba
- Mohammed VI Polytechnic University (UM6P), International Water Research Institute, Ben Guerir, 43150, Morocco
| | - Abdelghani Chehbouni
- Mohammed VI Polytechnic University (UM6P), International Water Research Institute, Ben Guerir, 43150, Morocco; CESBIO, Université de Toulouse, CNRS, CNES, IRD, BPI 280, 31065, Toulouse CEDEX 9, France
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6
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Hydrochemical, Isotopic, and Geophysical Studies Applied to the Evaluation of Groundwater Salinization Processes in Quaternary Beach Ridges in a Semiarid Coastal Area of Northern Patagonia, Argentina. WATER 2021. [DOI: 10.3390/w13243509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Quaternary sea level fluctuations have led to the development of beach ridges on many South Atlantic coasts. The objective of this paper was to asses from lithological, hydrochemical, isotopic, and geophysical studies the salinization processes affecting groundwater stored in Pleistocene and Holocene beach ridges of the northern Patagonian coast. A hydrogeomorphological characterization of the area was performed using digital elevation models, the interpretation of satellite images, and field studies. Vertical electrical soundings were performed on transects running perpendicular to beach ridges in order to define variations in the freshwater-saltwater interface position. The salinity, chemistry, and stable isotopes of the groundwater were analyzed. The results demonstrated that the groundwater salinization of Pleistocene ridges responds to processes associated with the geological-geomorphological evolution of the area. The cementation of these surface sediments limits rainwater infiltration, which consequently prevents the development of freshwater lenses. This suggests that saline water is the result of ancient marine ingressions. Freshwater lenses develop in Holocene beach ridges; however, slight water salinization is detectable in the most populated areas as a result of intensive exploitation. The data provided are useful for freshwater resource prospection along the arid coast of Patagonia, where beach ridge deposits abound and populations experience serious drinking water supply problems.
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7
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Chen X, Jiang C, Zheng L, Zhang L, Fu X, Chen S, Chen Y, Hu J. Evaluating the genesis and dominant processes of groundwater salinization by using hydrochemistry and multiple isotopes in a mining city. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 283:117381. [PMID: 34034018 DOI: 10.1016/j.envpol.2021.117381] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
The increasing salinization of groundwater renders it challenging to maintain the water quality. Moreover, knowledge regarding the characteristics and mechanism of groundwater salinization in mining areas remains limited. This study represents the first attempt of combining the hydrochemical, isotope (δD, δ18O, δ37Cl, and 87Sr/86Sr) and multivariate statistical analysis methods to explore the origin, control, and influence of fluoride enrichment in mining cities. The TDS content of groundwater ranged from 275.9 mg/L to 2452.0 mg/L, and 54% of the groundwater samples were classified as class IV water according to China's groundwater quality standards (GB/T 14848-2017), indicating a decline in the water quality of the study area. The results of the groundwater ion ratio and isotope discrimination analysis showed that dissolution and evaporation involving water-rock interactions and halite were the main driving processes for groundwater salinization in the study area. In addition to the hydrogeological and climatic conditions, mine drainage inputs exacerbated the increasing salinity of the groundwater in local areas. The mineral dissolution, cation exchange, and evaporation promoted the F- enrichment, while excessive evaporation and salinity inhibited the F- enrichment. Gangue accumulation and infiltration likely led to considerable F- enrichment in individual groundwater regions. Extensive changes in the groundwater salinity indicated differences in the geochemical processes that controlled the groundwater salinization. Given the particularity of the study area, the enrichment of salinization and fluoride triggered by mining activities cannot be ignored.
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Affiliation(s)
- Xing Chen
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Chunlu Jiang
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Liugen Zheng
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China.
| | - Liqun Zhang
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
| | - Xianjie Fu
- Pingan Mining Engineering Technology Research Institute Co., Ltd., Huainan, 232001, Anhui, China
| | - Shigui Chen
- Pingan Mining Engineering Technology Research Institute Co., Ltd., Huainan, 232001, Anhui, China
| | - Yongchun Chen
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan, 232001, Anhui, China
| | - Jie Hu
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China
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8
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Balwant P, Jyothi V, Pujari PR, Soni A, Padmakar C, Quamar R, Ramesh J, Gohel V, Mishra A. Integrated hydrochemical and ERT approach for seawater intrusion study in a coastal aquifer: a case study from Jafrabad Town, Gujarat State, India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:558. [PMID: 34365552 DOI: 10.1007/s10661-021-09251-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Hydrochemical and geophysical approach has been adopted to evaluate the seawater intrusion (SWI) in coastal aquifers of Jafrabad Town, Gujarat State, India. Electrical Resistivity Tomography (no. 9) was carried out with spread length of 160-400 m which provided penetration depth of about 23 to 76 m. Very low resistivity zone (0-3 Ω-m range) has been observed in the ERT profiles conducted in the study area. Parameters, namely, TDS, Na, and Cl, have been considered to examine the signature of SWI. The results obtained from ionic ratios, Piper plot, and Chaddha's diagram also confirm the influence of saline water within aquifer. The very low resistivity signature is correlated with the high TDS values in the nearby wells. SWI has been observed up to 9 km from the coast, and it is observed at a depth of 20-22 m in the existing limestone mines near the coast.
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Affiliation(s)
- Pandurang Balwant
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - V Jyothi
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - Paras R Pujari
- CSIR-National Environmental Engineering Research Institute, Nagpur, India.
| | - A Soni
- CSIR-Central Institute of Mining and Fuel Research, Nagpur, India
| | - C Padmakar
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - R Quamar
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - J Ramesh
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - V Gohel
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - A Mishra
- CSIR-National Environmental Engineering Research Institute, Nagpur, India
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9
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Ju Y, Massoudieh A, Green CT, Lee KK, Kaown D. Complexity of groundwater age mixing near a seawater intrusion zone based on multiple tracers and Bayesian inference. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:141994. [PMID: 32906048 DOI: 10.1016/j.scitotenv.2020.141994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/06/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
Aquifer flow systems near seawater interfaces can be complicated by density-driven flows and the formation of stagnation zones, which inevitably introduces uncertainty into groundwater age-dating. While age-dating has proved effective to understand the seawater intrusion and aquifer salinization process in coastal aquifers, further efforts are needed to propagate model and data uncertainty to the uncertainty associated with the inferred age distributions. This study was performed in a coastal aquifer located close to the Yellow Sea, South Korea, where there is a decreasing trend of groundwater levels due to recent heavy exploitation, raising a warning of induced seawater intrusion. We inferred the groundwater age distributions in wells around the intrusion zone and estimated the uncertainty associated with the inference based on multiple age tracers including 3H, tritiogenic 3He, radiogenic 4He, CFC-11, CFC-12 and CFC-113 using Bayesian inference. We examined various models representing the age distributions including traditional parametric Lumped Parameter Models (LPMs) and two non-parametric "shape-free" models. The results showed that the mean ages at the study site ranged from 10.9 to 522.5 y. Complex, multimodal distributions of ages occurred near a seawater intrusion area and upland recharge zones, implying converging paths of a wide range of different ages in those regions. In particular, the age distributions estimated near the seawater intrusion interface were characterized by heavy-tailed mixing structures with elevated concentrations of 4He. This likely indicates density-driven upward flow at the seawater intrusion interface, forcing old groundwater rich in 4He into the shallow aquifer. The Bayesian inference estimated large uncertainties particularly for the old age distributions, which was attributed partly to the gradual accumulation of 4He in groundwater. The Bayesian inference improved understanding of flow dynamics at a complex seawater interface and identified opportunities to further reduce uncertainty of old water age estimates that characterize upwelling groundwater near the interface.
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Affiliation(s)
- YeoJin Ju
- School of Earth and Environmental Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
| | - Arash Massoudieh
- Civil and Environmental Engineering, The Catholic University of America, Washington, DC, USA.
| | - Christopher T Green
- U.S. Geological Survey, Water Resources Mission Area, Moffett Field, CA, USA.
| | - Kang-Kun Lee
- School of Earth and Environmental Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
| | - Dugin Kaown
- School of Earth and Environmental Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
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10
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He Z, Han D, Song X, Yang S. Impact of human activities on coastal groundwater pollution in the Yang-Dai River plain, northern China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:37592-37613. [PMID: 32607995 DOI: 10.1007/s11356-020-09760-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Overexploitation of groundwater has resulted in seawater intrusion in many semiarid and arid coastal areas. This study illustrates the origin of groundwater salinity and assesses seawater intrusion/extrusion process in the Yang-Dai River plain aquifer, by analyzing hydrochemical and stable isotopic compositions of surface water, groundwater, geothermal water, and seawater. A cone of depression in groundwater is caused by intensive groundwater pumping formed in the late 1980s in the alluvial Yang-Dai River plain. In the northern part, groundwater exploitation has caused seawater intrusion identified by Ca-Cl type water. However, the widely distributed silty clay prevented the seawater intrusion in the southern part, evidenced by Ca-HCO3 type water with depleted δ2H (-60 to -46‰) and δ18O (-8.9 to -4.7‰). Anthropogenic pollution also plays a significant role in groundwater salinization. The positive correlation between Cl and NO3- for most groundwater and the extremely high nitrate concentrations (up to 652.7 mg/L) indicate that fertilizer from agricultural activities has greatly influenced groundwater quality. Irrigation return flow evaporation during agricultural activities also accounts for groundwater salinity. Besides the intensive fertilizer usage, seawater intrusion and the established anti-tide dams reduced the surface water and groundwater discharge to the sea and then resulted in the extremely high nitrate concentration. This study may improve the understanding of the groundwater salinization processes in a complex coastal aquifer, which is greatly influenced by anthropogenic activities.
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Affiliation(s)
- Zekang He
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongmei Han
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xianfang Song
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
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11
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Jasechko S, Perrone D, Seybold H, Fan Y, Kirchner JW. Groundwater level observations in 250,000 coastal US wells reveal scope of potential seawater intrusion. Nat Commun 2020; 11:3229. [PMID: 32591535 PMCID: PMC7319989 DOI: 10.1038/s41467-020-17038-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/27/2020] [Indexed: 11/25/2022] Open
Abstract
Seawater intrusion into coastal aquifers can increase groundwater salinity beyond potable levels, endangering access to freshwater for millions of people. Seawater intrusion is particularly likely where water tables lie below sea level, but can also arise from groundwater pumping in some coastal aquifers with water tables above sea level. Nevertheless, no nation-wide, observation-based assessment of the scope of potential seawater intrusion exists. Here we compile and analyze ~250,000 coastal groundwater-level observations made since the year 2000 in the contiguous United States. We show that the majority of observed groundwater levels lie below sea level along more than 15% of the contiguous coastline. We conclude that landward hydraulic gradients characterize a substantial fraction of the East Coast (>18%) and Gulf Coast (>17%), and also parts of the West Coast where groundwater pumping is high. Sea level rise, coastal land subsidence, and increasing water demands will exacerbate the threat of seawater intrusion. The authors here investigate in the susceptibility of coastal aquifers to seawater intrusion. Based on 20 years’ worth of observational data, the study finds that 15% of the US coastline is affected by landward hydraulic gradients conducive to seawater intrusion.
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Affiliation(s)
- Scott Jasechko
- Bren School of Environmental Science and Management, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA.
| | - Debra Perrone
- Environmental Studies Program, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Hansjörg Seybold
- Department of Environmental System Sciences, ETH Zürich, Universitätstrasse 16, Zürich, CH-8092, Switzerland
| | - Ying Fan
- Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, 08854, USA
| | - James W Kirchner
- Department of Environmental System Sciences, ETH Zürich, Universitätstrasse 16, Zürich, CH-8092, Switzerland.,Swiss Federal Research Institute WSL, Birmensdorf, CH-8903, Switzerland.,Department of Earth and Planetary Science, University of California, Berkeley, CA, 94720, USA
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12
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Nogueira G, Stigter TY, Zhou Y, Mussa F, Juizo D. Understanding groundwater salinization mechanisms to secure freshwater resources in the water-scarce city of Maputo, Mozambique. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 661:723-736. [PMID: 30684840 DOI: 10.1016/j.scitotenv.2018.12.343] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/13/2018] [Accepted: 12/22/2018] [Indexed: 06/09/2023]
Abstract
In this study hydrochemical, isotopic and multivariate statistical tools are combined with a recharge analysis and existing geophysical data to improve understanding of major factors controlling freshwater occurrence and the origins of high salinities in the multi-layered coastal aquifer system of the Great Maputo area in Mozambique. Access to freshwater in this semi-arid area is limited by an inefficient public supply network, scarce surface waters, long droughts and an increasing population growth. Groundwater has a large potential to enhance water security, but its exploitation is threatened by both coastal and inland salinization mechanisms that are poorly understood. A GIS approach is utilized to classify potential recharge zones based on hydrogeological properties and land use/cover, whereas potential recharge rates are estimated through a root zone water balance method. In combination with water stable isotope data results reveal that extreme rainfall events provide the most relevant contributions to recharge, and interception and evaporation play an important role in the low recharge areas. Hierarchical clustering of hydrochemical and isotopic data allows the classification of six water groups, varying from fresh to brackish/salt waters. Corresponding scatter plots and PHREEQC modelling show evaporation and mixing with seawater (up to 5%) as major processes affecting salinity in the area. The co-occurrence of high alkalinity and Cl concentrations, in combination with piezometric and geo-electrical data, suggests that: 1) inland brackish/salt groundwater is caused by mixing with seawater trapped within clay layers; and 2) brackish/salt surface waters result from seepage of brackish groundwater into rivers and wetlands, followed by evaporation, hence increasing salinity and δ18O values. Mixing with small fractions of trapped seawater as main salinity source, rather than halite dissolution, is further corroborated by Br/Cl ratios of brackish/salt water samples near the ocean ratio. Cation exchange upon salinization is mainly observed in the semi-confined aquifer, while freshening takes place in the phreatic aquifer, particularly in areas presenting high recharge rates.
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Affiliation(s)
- G Nogueira
- IHE Delft Institute for Water Education, Department of Water Science and Engineering, 2611 AX Delft, the Netherlands.
| | - T Y Stigter
- IHE Delft Institute for Water Education, Department of Water Science and Engineering, 2611 AX Delft, the Netherlands
| | - Y Zhou
- IHE Delft Institute for Water Education, Department of Water Science and Engineering, 2611 AX Delft, the Netherlands
| | - F Mussa
- Universidade Eduardo Mondlane, Department of Engineering, 3453 Maputo, Mozambique
| | - D Juizo
- Universidade Eduardo Mondlane, Department of Engineering, 3453 Maputo, Mozambique
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Malov AI. Evolution of groundwater chemistry in coastal aquifers of the south-eastern White Sea area (NW Russia) using 14C and 234U- 238U dating. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:1208-1223. [PMID: 29102188 DOI: 10.1016/j.scitotenv.2017.10.197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 10/03/2017] [Accepted: 10/19/2017] [Indexed: 06/07/2023]
Abstract
The specific objectives of the study are to clarify the sources and characteristics of groundwater in the aquifers along the coast of the White Sea in northwestern Russia, and on this basis to perform a broad 14C and 234U/238U dating of all their types, taking into account the mixing processes. Investigation of an evolution of the groundwater chemistry revealed that the main evolutionary trends are the following: (1) Mixing Late Pleistocene brackish water end member (brackish1) and Mikulino seawater end member with strongly brackish and salty water in the Vpd aquifer (salty Vpd) formation. Groundwater dating showed the "brackish1" residence time in the aquifer of 32.96±2.3ka. Recharge of "brackish1" could have occurred in MIS 3. (2) Mixing Late Pleistocene freshwater end member (fresh LP) and "salty Vpd" end member with brackish water (brackish2) formation. Groundwater dating showed the "brackish2" residence time in the aquifer from 25.1±0.7 to 39.2±6.3ka. Recharge of "fresh LP" could have occurred ~ in MIS 3 also. (3) Mixing Middle Pleistocene-Holocene freshwater of melting glaciers (fresh MP-H) end member and brine end member with the strongly brackish and salty water in Vmz aquifer (salty Vmz) formation. Recharge of "fresh MP-H" could have occurred in Middle Pleistocene-Holocene during MIS 12-MIS 1. As a result of intensive and rapid recharge after the glacial melting, glacial fluids have penetrated at depth to >200m. The results of this study provide a better understanding of the interrelationship of various groundwater flows near the coasts and contribute to a more justified and efficient use of them for drinking water supply in large cities, balneological treatment and industrial extraction of iodine waters. They also allow assessment of the risks of dumping saline drainage water into the environment.
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Affiliation(s)
- A I Malov
- Federal Center for Integrated Arctic Research of Russian Academy of Sciences, 23 Severnoy Dviny Emb., Arkhangelsk 163061, Russia.
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