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Zhu M, Chen J, He C, Ren S, Liu G. Multi-method characterization of groundwater nitrate and sulfate contamination by karst mines in southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174375. [PMID: 38960175 DOI: 10.1016/j.scitotenv.2024.174375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/05/2024]
Abstract
Groundwater contamination by nitrate and sulfate in mining areas is a significant challenge. Consequently, the inputs sources of these contaminants and their evolution have received considerable attention, with the knowledge gained critical for improved management of water quality. This study integrated data on multiple stable isotopes and water chemistry data and a Bayesian isotope mixing model to investigate the relative contributions of inputs sources of sulfate and nitrate sources to bodies of water in a karst mining area in southwest China. The outcomes indicated that hydrochemical component in the water bodies of the study area is mainly derived from the dissolution of silicate rocks, carbonate rocks and sulfate minerals as well as the oxidation of sulfides. The human and agricultural wastewater, soil nitrogen, and fertilizers were the predominant inputs sources of nitrate to the mine water environment; the predominant inputs sources of sulfide were mineral oxidation, evaporite dissolution, atmospheric deposition, and sewage. Groundwater is mainly recharged from atmospheric precipitation, and surface water is closely hydraulically connected to groundwater. Nitrogen and oxygen isotope composition and water chemistry indicative of nitrification dominate the nitrogen cycle in the study area. The oxidation of pyrite and bacterial sulfate reduction (SRB) had no significant impact on the stable isotopes of groundwater. The results of this study demonstrate the inputs of different sources to nitrate and sulfate in karst mines and associated transformation processes. The results of this study can assist in the conservation of groundwater quality in mining areas and can act as a reference for future related studies.
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Affiliation(s)
- Mingtan Zhu
- State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu 610059, PR China; College of Environment Civil Engineering, Chengdu University of Technology, Chengdu 610059, PR China
| | - Jiajing Chen
- College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, PR China
| | - Changlong He
- College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, PR China
| | - Shuang Ren
- College of Environment Civil Engineering, Chengdu University of Technology, Chengdu 610059, PR China
| | - Guo Liu
- State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu 610059, PR China; College of Environment Civil Engineering, Chengdu University of Technology, Chengdu 610059, PR China; College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, PR China.
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2
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Wu Y, Liu H, Zhang H, Li Q. Sources and seasonal variations of nitrate in the coastal multiple-aquifer groundwater of Beihai, southern China. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 262:104308. [PMID: 38301511 DOI: 10.1016/j.jconhyd.2024.104308] [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: 10/10/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
Elevated nitrate (NO3-) loadings in groundwater may cause health effects in drinking water and nutrient enrichment of aquatic ecosystems. To reveal the sources and seasonal variations of NO3- in the coastal groundwater of Beihai, southern China, we carried out hydrochemical and isotopic (δ15N-δ18O in NO3-) investigations in the summer and winter, respectively, concerning multiple-aquifer groundwater, rainwater, seawater, and surface water. The sources of the main elements present in the waters were interpreted by ionic ratios. NO3- sources were identified by combined use of the δ15N values and δ18O values or NO3-/Na+ molar ratios, with estimations of the proportional contribution by the Bayesian stable isotope mixing model. Denitrification was interpreted along the flow paths. The results show groundwater main elements are originated primarily from silicate weathering, and secondarily from anthropogenic inputs and carbonate dissolution. Its qualities are largely affected by seawater intrusion along the coastline. Because of difference in the predominant minerals within the aquifers and in scale and extent of seawater intrusion, the groundwater displays distinct ionic ratio characters. NO3- concentrations are up to 33.9 mg/L, with higher loadings in the plains relative to along the coastline. Soil N, domestic sewage, rainwater, chemical fertilizers, and algae are NO3- sources, with average proportional contributions of 0.255, 0.221, 0.207, 0.202, and 0.116, respectively. In relation to the winter, higher production of NO3- from nitrification of soil N- and algae-derived ammonium induced by higher temperatures in the summer accounts for increases in groundwater NO3- loadings. In the rural areas, elevated loadings of NO3- in the winter may be due to larger infiltration fractions of sewage. Seasonal variations of atmospheric NO3- deposition and farming may also cause the dynamics. Our results improve the understanding of sources and seasonal dynamics of NO3- in coastal groundwater.
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Affiliation(s)
- Ya Wu
- Wuhan Center, China Geological Survey, 430205 Wuhan, China.
| | - Huaiqing Liu
- Wuhan Center, China Geological Survey, 430205 Wuhan, China
| | - Hongxin Zhang
- Wuhan Center, China Geological Survey, 430205 Wuhan, China
| | - Qinghua Li
- Wuhan Center, China Geological Survey, 430205 Wuhan, China.
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Xu B, Lin Y, Wu Y, Wang Y. Identifying sources and transformations of nitrate in different occurrence environments of carbonate rocks using a coupled isotopic approach (δ 15N, δ 18O, 87Sr/ 86Sr) in karst groundwater system, North China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169300. [PMID: 38103615 DOI: 10.1016/j.scitotenv.2023.169300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/05/2023] [Accepted: 12/10/2023] [Indexed: 12/19/2023]
Abstract
Karst water as the vital water supply source is an increasingly serious problem suffering from NO3- pollution. Identifying sources and transformations is the key to effectively controlling diffuse NO3- pollution. In this study, 25 karst groundwater samples were collected from the Xujiagou karst groundwater system in June 2023, and chemical variables and stable isotopes (δ15N, δ18O, 87Sr/86Sr) were determined in different occurrence environments of carbonate rocks (exposed, covered, and buried carbonate rock areas). The results showed that the karst groundwater is dominated by nitrification. Human activities have affected the water quality of karst groundwater. The nitrate concentration ranged from 5.69 to 124.22 mg/L, and 4 % exceeds the quality indexes of class III water in China's standard for groundwater quality (20 mg/L as NO3--N). NH4+ in fertilizer, manure and septic waste, and soil N were the main sources of nitrate pollution in the karst groundwater system. The distribution of NO3- sources is closely related to land-use types. Soil N (72.2 %) became the dominant nitrate source in the exposed area due to the small amount of urban land and the large distribution of forest and grassland. There were more cultivated land and large agricultural activities in the covered area, NH4+ in fertilizer (59.1 %) contributes the most to NO3- sources. The buried area dominated by urban land, the influence of human activities (densely population and agricultural production activities) caused the highest concentration and coefficient of variation of nitrate in this area, and manure and septic waste (64.2 %) were the most to NO3- sources. This study can provide an important scientific basis for the protection of karst groundwater, and provide theoretical support for the treatment of karst groundwater pollution sources in the "monoclinic paraclinal" strata in northern China.
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Affiliation(s)
- Boyang Xu
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China
| | - Yun Lin
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Jiaozuo 454003, Henan Province, China.
| | - Yazun Wu
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China; Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region, Jiaozuo 454003, Henan Province, China
| | - Yiyang Wang
- School of Resources & Environment, Henan Polytechnic University, Jiaozuo 454003, China
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Li Y, Bian J, Xu P, Sun X, Sun W. Hydrochemistry and strontium isotope fingerprints of solute sources and CO 2 consumption in Changbai Mountain area, Northeast China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:91929-91944. [PMID: 37481495 DOI: 10.1007/s11356-023-28837-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/13/2023] [Indexed: 07/24/2023]
Abstract
As one of the most representative forms of groundwater, mineral water provides a critical understanding of regional hydrogeochemical features and rock weathering processes. However, current studies have mostly focused on the quality of mineral water and have rarely addressed the weathering process during its formation. Therefore, a multi-tracer approach combines chemical parameters, major ions, selected trace elements, and 87Sr/86Sr ratios for mineral water samples in Changbai Mountain during 2020-2021. First, we determined the hydrogeochemical characteristics of different types of mineral water. Secondly, the water-rock interaction processes governing the water mineralization were described to fix the hydrogeochemical background. Thirdly, the chemical weathering rate was calculated. The total dissolved load generated by rock weathering was around 6.76 tons/km2/year in the mineral water catchment area; 44.6% and 36.9% of the dissolved load were derived from silicate and carbonate weathering, respectively. The trace carbonates also played an important role in the overall rock weathering. Finally, after fully considering various influencing factors, we concluded that lithological characteristics and the soil environment rich in organic acids were the most important factors affecting rock weathering in the Changbai Mountain area. Overall, this study highlights the mineral water's role in the fluxes of CO2 in local area and reveals possible influence of the unique ecological and geological environment on rock weathering in Changbai Mountain. It can provide a reference for the subsequent assessment of environmental stability for basalt areas and the possibility of sustainable water resources development.
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Affiliation(s)
- Yihan Li
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China
- College of New Energy and Environment, Jilin University, Changchun, 130021, China
| | - Jianmin Bian
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China.
- College of New Energy and Environment, Jilin University, Changchun, 130021, China.
| | - Peng Xu
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China
- College of New Energy and Environment, Jilin University, Changchun, 130021, China
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, 100038, China
| | - Xiaoqing Sun
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China
- College of New Energy and Environment, Jilin University, Changchun, 130021, China
| | - Wenhao Sun
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China
- College of New Energy and Environment, Jilin University, Changchun, 130021, China
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Chen X, Zheng L, Zhu M, Jiang C, Dong X, Chen Y. Quantitative identification of nitrate and sulfate sources of a multiple land-use area impacted by mine drainage. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 325:116551. [PMID: 36283198 DOI: 10.1016/j.jenvman.2022.116551] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
The rapid increase in urbanization and intensive coal mining activities have accelerated the deterioration of surface water quality. Environmental problems caused by the accumulation of nitrate and sulfate from natural, urban, and agricultural sources have attracted extensive attention. Information on nitrate and sulfate sources and their transformations is crucial for understanding the nitrogen and sulfur cycles in surface water. In this study, we monitored nitrate and sulfate in three representative rivers in mining cities in northern China. The main pollution sources and biogeochemical processes were identified by using stable isotopes (δD, δ18OH2O, δ15N, δ18ONO3, δ34S and δ18OSO4) and hydrochemistry. The contribution of natural and anthropogenic sources was quantitatively estimated based on a Bayesian mixed model. The results indicated a large variation in sulfate and nitrate sources between the different rivers. Nitrate in the Tuohe River mainly derived from manure/sewage (57.9%) and soil N (26.9%), while sulfate mainly derived from manure/sewage (41.7%) and evaporite dissolution (26.8%). For the Suihe River, nitrate was primarily sourced from chemical fertilizer (37.9%) and soil nitrogen (34.8%), while sulfate was mainly sourced from manure/sewage (33.1%) and chemical fertilizer (21.4%). For the Huihe River, nitrate mainly derived from mine drainage (56.6%) and manure/sewage (30.6%), while sulfate predominantly originated from mine drainage (58.3%) and evaporite dissolution (12.9%). Microbial nitrification was the major pathway for the migration and transformation of nitrate in the surface water. However, denitrification and bacterial sulfate reduction (BSR) did not play a significant role as aerobic conditions prevailed. In this study, we elucidated the sources and transformation mechanisms of nitrate and sulfate. Additionally, we provided a reference for formulating a comprehensive strategy for effective management and remediation of surface water contaminated with nitrate and sulfate in mining cities.
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Affiliation(s)
- Xing Chen
- School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230601, Anhui, China; 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.
| | - Manzhou Zhu
- School of Chemistry and Chemical Engineering, Anhui University, 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
| | - Xianglin Dong
- Geological Survey Division, Huaibei Coal Mining Group Corporation, Huaibei, 235001, Anhui, China
| | - Yongchun Chen
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan, 232001, Anhui, China
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Keum G, Kim Y, Lee KS, Jeong J. The geochemistry and isotopic compositions of the Nakdong River, Korea: weathering and anthropogenic effects. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:487. [PMID: 35674833 DOI: 10.1007/s10661-022-10143-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
The Nakdong River is the longest river in South Korea, and flows through various geological terrains with different land use characteristics; therefore, the geochemistry of its water is expected to be influenced by many factors. In this work, the geochemical characteristics of the Nakdong River were examined, and its chemical compositions, δD, δ18O, and δ13CDIC values, and 87Sr/86Sr ratios were determined to investigate the geological and anthropogenic effects on the geochemistry of the Nakdong River water. The obtained concentrations of major ions were strongly affected by both the anthropogenic activity and weathering of the rocks. With increasing the flow distance, the ion concentrations slightly increased; and after the inflow of the Kumho River, which was the largest tributary running through Daegu (the fourth largest city in South Korea), the concentrations of Na and SO4 ions abruptly increased and decreased again, suggesting the existence of strong anthropogenic effects caused by sewage treatment plants and dyeing industrial complex. Other activities such as agricultural ones also increased the NO3 concentration. In July, the high precipitation level from tropical cyclones and downpours decreased the ion concentrations as well as the δD and δ18O values. The δ13CDIC magnitudes showed that the dissolved inorganic carbon mainly originated from mineral weathering upstream, while the oxidation of soil organic materials influenced by agricultural activity became more important downstream. The 87Sr/86Sr ratios revealed that in the upstream regions, the weathering of granite and gneiss complex was dominant, while in the downstream regions, the weathering of sedimentary rocks became more important. The weathering and anthropogenic effects on the river water chemistry were also demonstrated using statistical analysis, which revealed that the water geochemistry was mostly influenced by the anthropogenic sources, including industrial complex, represented by Na, Cl, and SO4. The obtained results show that, as compared to the geochemistry of the Han River (which is also a major river in Korea), the geochemistry of the Nakdong River is more influenced by anthropogenic activities (including agriculture and the industrial complex) due to the different land use.
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Affiliation(s)
- Gyojin Keum
- School of Earth System Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Yeongkyoo Kim
- School of Earth System Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
| | - Kwang-Sik Lee
- Korea Basic Science Institute, Daejeon, 34133, Republic of Korea
| | - Jina Jeong
- School of Earth System Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea
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Abongwa PT, Den W, Teague A. Chemical and Carbon Isotopic Characterization of a Karst-Dominated Urbanized Watershed: Case of the Upper San Antonio River. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2022; 82:439-454. [PMID: 35347352 DOI: 10.1007/s00244-022-00921-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Urbanization and agriculture are two key factors that place demands on water resources and serve as sources of anthropogenic pollution into inland waterways. The San Antonio River, which is sourced from a karst aquifer, plays an important recreational and scenic role, yet effective management is often hampered by the lack of understanding of the chemical characterization of the water system. The karst-dominated Edwards Aquifer watershed in south-central Texas is an ideal watershed to understand water-rock interaction (carbonate dissolution) and anthropogenic impact on our water resources. In order to understand groundwater-surface water interactions, we made chemical and isotopic measurements over a 17-km stretch of the San Antonio River beginning at the headwater sanctuary and moving downstream. The chemistry of the headwaters and at along the longitudinal profile of the river showed that the Edwards Aquifer is dominated by Ca2+, Mg2+ and HCO3- ions resulting from carbonate dissolution. The carbon isotopic signature of dissolved inorganic carbon (δ13CDIC) showed that the Edwards Aquifer is in chemical and isotopic equilibrium with soil CO2(g). The relationships between δ13CDIC and solutes (Cl-, Na+, F-, NO3-) showed that anthropogenic sources of these solutes are associated with low δ13CDIC values, indicating that carbon isotopic composition of dissolved inorganic carbon can be a useful tracer for contaminants in the environment. The anthropogenic inputs into the San Antonio River were sourced mainly from effluents of the San Antonio Zoo, waste discharge from the River Walk in downtown San Antonio and from fertilizers and animal waste in the less urbanized section of the sampled area (Mission Concepcion to Mission Espada). To protect and sustain the water quality of urban waterways and karst aquifers, urban sewage and effluents must be treated and controlled.
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Affiliation(s)
- Pride T Abongwa
- Institute for Water Resources Science and Technology, Texas A&M University-San Antonio, One University Way, San Antonio, TX, 78224, USA.
- Department of Mathematical, Physical and Engineering Sciences, Texas A&M University-San Antonio, One University Way, San Antonio, TX, 78224, USA.
| | - Walter Den
- Institute for Water Resources Science and Technology, Texas A&M University-San Antonio, One University Way, San Antonio, TX, 78224, USA
- Department of Mathematical, Physical and Engineering Sciences, Texas A&M University-San Antonio, One University Way, San Antonio, TX, 78224, USA
| | - Aarin Teague
- San Antonio River Authority, San Antonio, TX, 78283, USA
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Su H, Kang W, Li Y, Li Z. Fluoride and nitrate contamination of groundwater in the Loess Plateau, China: Sources and related human health risks. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117287. [PMID: 33971470 DOI: 10.1016/j.envpol.2021.117287] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/14/2021] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
Fluoride (F-) and nitrate (NO3-) in groundwater have caused serious health problems worldwide. However, in the Chinese Loess Plateau where groundwater is the primary source of drinking water, previous studies have rarely reported the health risks from fluoride and nitrate in groundwater. Therefore, we collected 105 groundwater samples (78 from shallow aquifers and 27 from deep aquifers) from the western district of the Loess Plateau for physicochemical and isotopic analysis to investigate the sources of F- and NO3- in groundwater and associated health risks. Fluoride concentration in 73.1% of shallow groundwater and 22.2% of deep groundwater exceeds 1.5 mg/L, while NO3- content in 76.3% of shallow groundwater and 51.9% of deep groundwater surpasses 50 mg/L. High-F- groundwater is associated with HCO3-Na, SO4-Na·Mg and Cl-Na·Mg types water. Fluorine-bearing minerals dissolution, cation exchange, calcite precipitation, evaporation, and anthropogenic activities contribute significantly F- in groundwater. Mixing with shallow groundwater is an important source of F- in deep groundwater. The NO3- content is highest in Cl type water, followed by SO4 type and HCO3 type water. NO3- mainly originates from soil organic nitrogen (SON), chemical fertilizers (CF), and manure and sewage (M&S). Nitrification is the dominant transformation process of nitrogen nutrients in groundwater. The hazard index (HI) values for shallow groundwater are 0.203-9.232 for adults, 0.253-11.522 for teenagers, 0.359-16.322 for children, and 0.507-23.043 for infants, while those for deep groundwater are 0.713-5.813 for adults, 0.890-7.254 for teenagers, 1.261-10.277 for children, and 1.780-14.508 for infants. Approximately 96.2% of shallow groundwater poses non-carcinogenic risks to infants and children, followed by 92.3% to teenagers, and 89.7% to adults. All deep groundwater poses non-carcinogenic risks to infants and children, followed by 92.6% to teenagers, and 74.1% to adults. This study is helpful to develop strategies for the integrated management of high fluoride or nitrate groundwater in arid areas.
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Affiliation(s)
- He Su
- Department of Earth Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Weidong Kang
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, 710069, China
| | - Yanrong Li
- Department of Earth Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
| | - Zhi Li
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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Using Isotopic and Hydrochemical Indicators to Identify Sources of Sulfate in Karst Groundwater of the Niangziguan Spring Field, China. WATER 2021. [DOI: 10.3390/w13030390] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Karst groundwater in the Niangziguan spring fields is the main source to supply domestic and industrial water demands in Yangquan City, China. However, the safety of water supply in this region has recently suffered from deteriorating quality levels. Therefore, identifying pollution sources and causes is crucial for maintaining a reliable water supply. In this study, a systematic sample collection for the karst groundwater in the Niangziguan spring fields was implemented to identify hydrochemical characteristics of the karst groundwater through comprehensive analyses of hydrochemistry (piper diagram, and ion ratios,) and stable isotopes (S and H-O). The results show that the karst groundwater in the Niangziguan spring fields was categorized as SO4·HCO3-Ca·Mg, HCO3·SO4-Ca·Mg, and SO4-Ca types. K+, Cl-, and Na+ are mainly sourced from urban sewage and coal mine drainage. In addition, SO42− was mainly supplied by the dissolution of gypsum and the oxidation of FeS2 in coal-bearing strata. It is noteworthy that, based on H-O and S isotopes, 75% of the karst groundwater was contaminated by acidic water in coal mines at different degrees. In the groundwater of the Niangziguan spring field, the proportions of SO42− derived from FeS2 oxidation were 60.6% (N50, Chengxi spring), 30.3% (N51, Wulong spring), and 26.0% (N52, Four springs mixed with water). Acid mine drainage directly recharges and pollutes karst groundwater through faults or abandoned boreholes, or discharges to rivers, and indirectly pollutes karst groundwater through river infiltration in carbonate exposed areas. The main source of rapid increase of sulfate in karst groundwater is acid water from abandoned coal mines.
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Wang F, Chen H, Lian J, Fu Z, Nie Y. Hydrological response of karst stream to precipitation variation recognized through the quantitative separation of runoff components. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:142483. [PMID: 33113671 DOI: 10.1016/j.scitotenv.2020.142483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 09/17/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
Various water transmitting media are related to highly variable water source compositions, which limit the understanding of the aquifer structure and hydrological processes in a karst catchment. This study aims to understand the variation in water contribution by matrix, fissure, and conduit flows during storm and seasonal scales based on discharge, electrical conductivity (EC), and nitrate measurements of stream water in a typical dolomite catchment during 2017-2018 and discusses the hydrological response mechanism of a karst aquifer to rainfall characteristics. Time-series analyses of discharge and EC indicated that the rapid response time (mean lag time < 1 h) was mainly controlled by rainfall intensity, and the lag time decreased significantly when the rainfall intensity was lower than 15 mm/h. However, the mean discharge was dominated by the rainfall amount and antecedent moisture state. Hydrograph separation based on nitrate indicates that the contribution of soil water was irrelevant for recharging the stream during a non-rain period, whereas epikarst water contributed more than 83.2% of the total flow during a rainfall event. As indicated by the EC frequency distribution analyses, the contribution ratios of the surface, conduit, fissure, and matrix flows were 1:1.8:2.1:7.1, 1:1.6:5.3:6.3, and 0:0:0:1 during stormy, heavy, and light rainfall events, respectively. These parameters indicate that the degree of karstification was low in the karst aquifer. Seasonal frequency distribution analyses of EC indicate that higher rainfall amounts and rainfall intensities during the wet season promoted the contribution of conduit flow to approximately 11.4% of the total flow; however, matrix flow dominated the recharge of the streamflow and its contribution was more than 55.6% during each season. Our results suggest that the permeability of the epikarst matrix dominates the storage and transfer functions in dolomite karst aquifers with low karstification.
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Affiliation(s)
- Fa Wang
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongsong Chen
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China.
| | - Jinjiao Lian
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China.
| | - Zhiyong Fu
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China.
| | - Yunpeng Nie
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China.
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11
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Zhang H, Xu Y, Cheng S, Li Q, Yu H. Application of the dual-isotope approach and Bayesian isotope mixing model to identify nitrate in groundwater of a multiple land-use area in Chengdu Plain, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 717:137134. [PMID: 32070893 DOI: 10.1016/j.scitotenv.2020.137134] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/03/2020] [Accepted: 02/03/2020] [Indexed: 06/10/2023]
Abstract
Nitrate (NO3-) contamination in groundwater is an environmental problem worldwide. Partitioning the pollution into its sources is the key for effective controls. In this study, NO3- dual isotopic compositions (δ15N-NO3- and δ18O-NO3-) were measured in groundwater samples from 28 wells in an area with multiple land-uses, followed by the application of an isotope mixing model (SIAR) to identify the main NO3- sources and their biogeochemical processes. The results showed that denitrification was unlikely occur at significant rates, while nitrification was an important nitrogen transformation processes. Spatial variation of groundwater NO3- and its isotopic compositions was associated with the land-use types. Agricultural areas were characterized by relatively high NO3- concentrations and low δ15N-NO3- values. In contrast, industrial areas were characterized by enriched δ15N-NO3- and δ18O-NO3- values. In crop field, vegetable field and poultry and livestock breading farm, the proportional contribution represented a similar pattern with highest contribution from chemical fertilizer followed by soil organic nitrogen, manure, atmospheric precipitation and sewage in order. Nitrate in groundwater in industrial areas has different pattern of the proportional contribution, in which groundwater NO3- is largely influenced by sewage discharge and atmospheric precipitation. We concluded that the combination of isotopic analysis together with land-use information and chemical analysis was an effective approach for assessing the source apportionment and the fate of nitrate in the aquifer in multiple land-use areas.
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Affiliation(s)
- Han Zhang
- Faulty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China.
| | - Yi Xu
- Faulty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Siqian Cheng
- Faulty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Qiling Li
- Faulty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Haoran Yu
- Faulty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China
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Ren K, Pan X, Zeng J, Yuan D. Contaminant sources and processes affecting spring water quality in a typical karst basin (Hongjiadu Basin, SW China): insights provided by hydrochemical and isotopic data. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:31354-31367. [PMID: 31473924 DOI: 10.1007/s11356-019-06272-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Springs are an important source of drinking water supply in mountainous karst areas of SW China. However, the quality of many spring waters has deteriorated greatly in recent years, which leads to a significant problem of drinking water scarcity. In this study, hydrochemistry and stable sulfur and oxygen isotopic compositions of SO42- (δ34S and δ18OSO4) of 38 representative samples of waters (incl. spring water, surface water, rainwater, and sewage) from the Hongjiadu Basin, Guizhou province, SW China, were investigated in order to identify the sources of contaminates in spring waters and trace the processes affecting the karst groundwater quality. Approximately 28% of the total investigated springs has been suffered from serious contamination and the concentrations of NO3-, SO42-, and total iron (TFe) in many spring waters have exceeded the standards for drinking water. The springs that have NO3- concentrations of > 30 mg/L are concentrated in residential and agricultural areas, suggesting that NO3- in spring water are mainly derived from chemical fertilizers, manure, and sewage. δ34S and δ18OSO4 data indicate that SO42- in spring water mainly originates from sulfide oxidation, acid rain, and sewage. Furthermore, the high δ34S and δ18OSO4 values of SO42- in some spring waters may be related to the occurrence of bacterial sulfate reduction. Some springs that are discharged from abandoned coal mines have SO42- concentrations of > 250 mg/L, demonstrating that mining activities have accelerated the deterioration of spring water quality. Also, springs with TFe concentrations of > 0.3 mg/L are discharged from coal-bearing strata, revealing that iron in spring waters is mainly derived from the oxidation of pyrite. Our results show that the karst spring waters are highly vulnerable to anthropogenic contaminations and human activities, such as agricultural fertilizing and sewage and waste disposal as well as mining activities, which exert a great impact on the quality of groundwater in karst areas.
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Affiliation(s)
- Kun Ren
- Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
- Karst Dynamics Laboratory, Ministry of Natural Resources & Guangxi, Guilin, 541004, China
| | - Xiaodong Pan
- Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China.
- Karst Dynamics Laboratory, Ministry of Natural Resources & Guangxi, Guilin, 541004, China.
| | - Jie Zeng
- Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
- Karst Dynamics Laboratory, Ministry of Natural Resources & Guangxi, Guilin, 541004, China
| | - Daoxian Yuan
- Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
- Karst Dynamics Laboratory, Ministry of Natural Resources & Guangxi, Guilin, 541004, China
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