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Li Y, Guo H, Zhao B, Gao Z, Yu C, Zhang C, Wu X. High biodegradability of microbially-derived dissolved organic matter facilitates arsenic enrichment in groundwater: Evidence from molecular compositions and structures. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134133. [PMID: 38574655 DOI: 10.1016/j.jhazmat.2024.134133] [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: 12/20/2023] [Revised: 03/16/2024] [Accepted: 03/24/2024] [Indexed: 04/06/2024]
Abstract
Although biodegradation of organic matter is well-known to trigger enrichment of arsenic (As) in groundwater, the effects of DOM sources and biodegradability on As enrichment remain elusive. In this study, groundwater samples were collected from the Hetao basin to identify DOM source and evaluate biodegradability by using spectral and molecular techniques. Results showed that in the alluvial fan, DOM was mainly sourced from terrestrially derived OM, while DOM in the flat plain was more originated from microbially derived OM. Compared to terrestrially derived DOMs, microbially derived DOMs in groundwater, which had relatively higher H/Cwa ratios, NOSC values and more biodegradable molecules, exhibited higher biodegradability. In the flat plain, microbially derived DOMs with higher biodegradability encountered stronger biodegradation, facilitating the reductive dissolution of Fe(III)/Mn oxides and As enrichment in groundwater. Moreover, the enrichment of As depended on the biodegradable molecules that was preferentially utilized for primary biodegradation. Our study highlights that the enrichment of dissolved As in the aquifers was closely associated with microbially derived DOM with high biodegradability and high ability for primary biodegradation.
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Affiliation(s)
- Yao Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Huaming Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China.
| | - Bo Zhao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Zhipeng Gao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Chen Yu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Chaoran Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 100083 Beijing, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
| | - Xiong Wu
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), 100083 Beijing, China
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Du Y, Xiong Y, Deng Y, Tao Y, Tian H, Zhang Y, Li Q, Gan Y, Wang Y. Geogenic Phosphorus Enrichment in Groundwater due to Anaerobic Methane Oxidation-Coupled Fe(III) Oxide Reduction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8032-8042. [PMID: 38670935 DOI: 10.1021/acs.est.4c00267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Accumulation of geogenic phosphorus (P) in groundwater is an emerging environmental concern, which is closely linked to coupled processes involving FeOOH and organic matter under methanogenic conditions. However, it remains unclear how P enrichment is associated with methane cycling, particularly the anaerobic methane oxidation (AMO). This study conducted a comprehensive investigation of carbon isotopes in dissolved inorganic carbon (DIC), CO2, and CH4, alongside Fe isotopes, microbial communities, and functions in quaternary aquifers of the central Yangtze River plain. The study found that P concentrations tended to increase with Fe(II) concentrations, δ56Fe, and δ13C-DIC, suggesting P accumulation due to the reductive dissolution of FeOOH under methanogenic conditions. The positive correlations of pmoA gene abundance versus δ13C-CH4 and Fe concentrations versus δ13C-CH4, and the prevalent presence of Candidatus_Methanoperedens, jointly demonstrated the potential significance of Fe(III)-mediated AMO process (Fe-AMO) alongside traditional methanogenesis. The increase of P concentration with δ13C-CH4 value, pmoA gene abundance, and Fe concentration suggested that the Fe-AMO process facilitated P enrichment in groundwater. Redundancy analysis confirmed this assertion, identifying P concentration as the primary determinant and the cooperative influence of Fe-AMO microorganisms such as Candidatus_Methanoperedens and Geobacter on P enrichment. Our work provided new insights into P dynamics in subsurface environments.
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Affiliation(s)
- Yao Du
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
| | - Yaojin Xiong
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
| | - Yamin Deng
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
| | - Yanqiu Tao
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
| | - Hao Tian
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
| | - Yanpeng Zhang
- Wuhan Center of China Geological Survey, Wuhan 430205, China
| | - Qinghua Li
- Wuhan Center of China Geological Survey, Wuhan 430205, China
| | - Yiqun Gan
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
| | - Yanxin Wang
- Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, Wuhan 430078, China
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3
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Chen J, Zhang X, Kuang M, Cui K, Xu T, Liu X, Zhuo R, Qin Z, Bu Z, Huang Z, Li H, Huang J, Liu T, Zhu Y. Endophytic Enterobacter sp. YG-14 mediated arsenic mobilization through siderophore and its role in enhancing phytostabilization. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133206. [PMID: 38134692 DOI: 10.1016/j.jhazmat.2023.133206] [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: 10/07/2023] [Revised: 11/26/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023]
Abstract
Soil arsenic (As) phytoremediation has long faced the challenge of efficiently absorbing As by plant accumulators while maintaining their health and fast growth. Even at low doses, arsenic is highly toxic to plants. Therefore, plant growth-promoting microorganisms that can mediate As accumulation in plants are of great interest. In this study, the endophyte Enterobacter sp. YG-14 (YG-14) was found to have soil mobilization activity. By constructing a siderophore synthesis gene deletion mutant (ΔentD) of YG-14, the endophyte was confirmed to effectively mobilize Fe-As complexes in mining soil by secreting enterobactin, releasing bioavailable Fe and As to the rhizosphere. YG-14 also enhances As accumulation in host plants via extracellular polymer adsorption and specific phosphatase transfer protein (PitA) absorption. The root accumulation of As was positively correlated with YG-14 root colonization. In addition, YG-14 promoted plant growth and alleviated oxidative damage in R. pseudoacacia L. under arsenic stress. This is the first study, from phenotype, physiology, and molecular perspectives, to determine the role of endophyte in promoting As phytostabilization and maintaining the growth of the host plant. This demonstrated the feasibility of using endophytes with high siderophore production to assist host plants in As phytoremediation.
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Affiliation(s)
- Jiawei Chen
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Xuan Zhang
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, PR China
| | - Min Kuang
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Kunpeng Cui
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Ting Xu
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Xuanming Liu
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Rui Zhuo
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Ziwei Qin
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Zhigang Bu
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China
| | - Zhongliang Huang
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, PR China
| | - Hui Li
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, PR China
| | - Jing Huang
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, PR China
| | - Tingting Liu
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, PR China
| | - Yonghua Zhu
- Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, Hunan, PR China.
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4
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Tao Y, Du Y, Deng Y, Liu P, Ye Z, Zhang X, Ma T, Wang Y. Coupled Processes Involving Organic Matter and Fe Oxyhydroxides Control Geogenic Phosphorus Enrichment in Groundwater Systems: New Evidence from FT-ICR-MS and XANES. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17427-17438. [PMID: 37697639 DOI: 10.1021/acs.est.3c03696] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
The enrichment of geogenic phosphorus (P) in groundwater systems threatens environmental and public health worldwide. Two significant factors affecting geogenic P enrichment include organic matter (OM) and Fe (oxyhydr)oxide (FeOOH). However, due to variable reactivities of OM and FeOOH, variable strategies of their coupled influence controlling P enrichment in groundwater systems remain elusive. This research reveals that when the depositional environment is enriched in more labile aliphatic OM, its fermentation is coupled with the reductive dissolution of both amorphous and crystalline FeOOHs. When the depositional environment is enriched in more recalcitrant aromatic OM, it largely relies on crystalline FeOOH acting concurrently as electron acceptors while serving as "conduits" to help itself stimulate degradation and methanogenesis. The main source of geogenic P enriched by these two different coupled processes is different: the former is P-containing OM, which mainly contained unsaturated aliphatic compounds and highly unsaturated-low O compounds, and the latter is P associated with crystalline FeOOH. In addition, geological setting affects the deposition rate of sediments, which can alter OM degradation/preservation, and subsequently affects geochemical conditions of geogenic P occurrence. These findings provide new evidence and perspectives for understanding the hydro(bio)geochemical processes controlling geogenic P enrichment in alluvial-lacustrine aquifer systems.
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Affiliation(s)
- Yanqiu Tao
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Yao Du
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Yamin Deng
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Peng Liu
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Zhihang Ye
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Xinxin Zhang
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Teng Ma
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
| | - Yanxin Wang
- MOE Key Laboratory of Groundwater Quality and Health, China University of Geosciences, Wuhan 430078, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan 430078, China
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5
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Qu S, Luo Y, Duan L, Pei S, Miao P, Wang C, Liu T, Yu R. Deciphering spatio-seasonal patterns, driving forces, and human health risks of nitrate and fluoride enriched water bodies in the Inner Mongolia Reaches of the Yellow River Basin, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:111423-111440. [PMID: 37816964 DOI: 10.1007/s11356-023-29914-7] [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: 03/02/2023] [Accepted: 09/12/2023] [Indexed: 10/12/2023]
Abstract
The ecology and environment of the Yellow River Basin is threatened by fluoride and nitrate contamination induced by anthropogenic activity and geogenic factors. As a result, deciphering the spatio-temporal variability of fluoride and nitrate contamination in this area remains a challenge. Three hundred eighty-six samples of surface water and groundwater from the Inner Mongolia Reaches of the Yellow River Basin were taken for this investigation. According to the results of the multivariate statistical and geostatistical analyses, the fluoride pollution was primarily discovered in the middle and lower reaches of the study area and was determined to be more severe during the dry season. In contrast, nitrate contamination was found to be more severe during the wet season while being widely distributed in groundwater and concentrated in areas with intensive agricultural activities. The primary mechanisms governing the spatial-seasonal patterns of NO3- and F- pollution were shown by the principal component analysis, isotopic, and hydrochemical diagrams. The water-rock interaction or evaporation was crucial in the enrichment of F-. The human inputs (e.g., fertilizer or sewage) dominated fluoride and nitrate contamination. Additionally, the alkaline environment played a role in the generation of NO3- and F-. The health risk assessment concluded that the threat of fluoride contamination was greater than that of nitrate contamination. Children faced the greatest health risks, followed by females and males. These findings would serve as a guide for water management and pollution control in the Yellow River Basin.
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Affiliation(s)
- Shen Qu
- Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China
| | - Yanyun Luo
- Water and Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Limin Duan
- Water and Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, 010018, China.
| | - Sensen Pei
- Water and Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Ping Miao
- River and Lake Protection Center, Ordos Water Conservancy Bureau, Ordos, 017000, China
| | - Chenyu Wang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences, Beijing, 100083, China
| | - Tingxi Liu
- Water and Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Ruihong Yu
- Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China
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Liu H, Xie X, Cao H, Wang Y. Insights into the selectivity of metallic oxides for arsenic and phosphate from EXAFS and DFT calculations. CHEMOSPHERE 2023; 336:139276. [PMID: 37343632 DOI: 10.1016/j.chemosphere.2023.139276] [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: 11/16/2022] [Revised: 04/07/2023] [Accepted: 06/18/2023] [Indexed: 06/23/2023]
Abstract
Phosphate is the biggest competitor for arsenic removal. Nanoscale metal oxides (NMOs) are commonly used to treat arsenic-contaminated water, yet their selective adsorption mechanisms for arsenic and phosphate are poorly understood. We quantified the selectivity of iron oxide (Fe2O3), zinc oxide (ZnO), and titanium dioxide (TiO2) nanosheets for arsenic in systems containing arsenic and phosphate, and determined the interaction of phosphate and arsenate/arsenite on metal oxide surfaces through batch experiments, spectroscopic techniques, and DFT calculations. We found that Fe2O3, TiO2, and ZnO nanosheets exhibit selectivity for arsenate/arsenite in the presence of phosphate, with Fe2O3 the most selective, followed by TiO2 and ZnO. The bonding mechanism on these metallic oxide surfaces dominates the selectivity. The more stable inner-sphere complexes of arsenate on the surfaces of Fe2O3 (bidentate binuclear), TiO2 (bidentate binuclear), and ZnO nanosheets (tridentate trinuclear) contribute to their preference for arsenate over phosphate. This difference in arsenate selectivity can be reflected in the difference in adsorption energy, net electron transfer number, and M - O bond length of the most stable inner sphere complexes. Overall, our study elucidated the selective adsorption mechanisms of arsenate/arsenite on Fe2O3, TiO2, and ZnO surfaces and highlighted the need to consider the competition between arsenate and phosphate during their removal from contaminated water.
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Affiliation(s)
- Hongxing Liu
- School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074, Wuhan, China
| | - Xianjun Xie
- School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074, Wuhan, China.
| | - Hailong Cao
- School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074, Wuhan, China
| | - Yanxin Wang
- School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074, Wuhan, China
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7
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Zhang X, Ke X, Du Y, Tao Y, Xue J, Li Q, Xie X, Deng Y. Coupled effects of sedimentary iron oxides and organic matter on geogenic phosphorus mobilization in alluvial-lacustrine aquifers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:163216. [PMID: 37004762 DOI: 10.1016/j.scitotenv.2023.163216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 03/13/2023] [Accepted: 03/28/2023] [Indexed: 05/13/2023]
Abstract
The organic matter (OM) biodegradation and reductive dissolution of iron oxides have been acknowledged as key factors in the release of geogenic phosphorus (P) to groundwater. However, the coupled effects of natural OM with iron oxides on the mobilization of geogenic P remain unclear. Groundwater with high and low P concentrations has been observed in two boreholes in the alluvial-lacustrine aquifer system of the Central Yangtze River Basin. Sediment samples from these boreholes were examined for their P and Fe species as well as their OM properties. The results show that sediments from borehole S1 with high P levels contain more bioavailable P, particularly iron oxide bound P (Fe-P) and organic P (OP) than those from borehole S2 with low P levels. Regarding borehole S2, Fe-P and OP show positive correlations with total organic carbon as well as amorphous iron oxides (FeOX1), which indicate the presence of Fe-OM-P ternary complexes, further evidenced by FTIR results. In a reducing environment, the protein-like component (C3) and terrestrial humic-like component (C2) will biodegrade. In the process of C3 biodegradation, FeOX1 will act as electron acceptors and then undergo reductive dissolution. In the process of C2 biodegradation, FeOX1 and crystalline iron oxides (FeOX2) will act as electron acceptors. FeOX2 will also act as conduits in the microbial utilization pathway. However, the formation of stable P-Fe-OM ternary complexes will inhibit the reductive dissolution of iron oxides and OM biodegradation, thus inhibiting the mobilization of P. This study provides new insights into the enrichment and mobilization of P in alluvial-lacustrine aquifer systems.
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Affiliation(s)
- Xinxin Zhang
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Xianzhong Ke
- Wuhan Center, China Geological Survey (Central South China Innovation Center for Geosciences), Wuhan 430205, China
| | - Yao Du
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Yanqiu Tao
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Jiangkai Xue
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Qinghua Li
- Wuhan Center, China Geological Survey (Central South China Innovation Center for Geosciences), Wuhan 430205, China
| | - Xianjun Xie
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Yamin Deng
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, China University of Geosciences, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China.
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8
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Liu Z, Du Y, Deng Y, Huang Y, Zhao X, Li Q. Enrichment of geogenic phosphorus in a coastal groundwater system: New insights from dissolved organic matter characterization. CHEMOSPHERE 2023; 322:138214. [PMID: 36841455 DOI: 10.1016/j.chemosphere.2023.138214] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/13/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
High concentrations of geogenic phosphorus (P) in coastal aquifer systems pose a serious and continuous threat to the health of marine ecosystems. A major source for geogenic P enrichment in aquifer systems is the mineralization of P-containing organic matter. However, the mechanisms that drive the enrichment remain unclear. Therefore, our study sought to characterize the occurrence, sources, and enrichment mechanisms of geogenic P in a coastal confined aquifer system of the Pearl River Delta, southern China. To achieve this, we conducted Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and fluorescence excitation-emission-matrix spectra (EEMs) as well as hydrochemistry and stable carbon isotope analyses. Our findings indicated that intense degradation of P-containing organic matter produced up to 8.07 mg/L of geogenic P in a reducing environment with abundant organic matter. The dissolved organic matter (DOM) of high-P groundwater (P > 1 mg/L) contained more humic-like fluorophores and exhibited higher humification. Groundwater with high P concentrations contained more aliphatic compounds and highly unsaturated-low O compounds, and the enrichment of P was mostly associated with CHOP compounds in the region of aliphatic compounds and CHON2P compounds in the region of highly unsaturated-low O compounds. Different types of dissolved organic phosphorus (DOP) can be mineralized into P, and even the mineralization of phosphonates takes precedence over the more unstable phosphate esters. P produced by the metabolism of different types of DOP was assimilated by marine microorganisms (e.g., heterotrophic bacteria and archaea), and the newly synthesized organic P compounds by chemosynthesis were subsequently released into the groundwater. Over time, P continues to be enriched in the aquifer system. This study provides new insights into subsurface P cycling in coastal aquatic systems.
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Affiliation(s)
- Zhaohui Liu
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430078, China; Geological Survey Institute, China University of Geosciences, Wuhan, 430074, China
| | - Yao Du
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430078, China.
| | - Yamin Deng
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430078, China
| | - Yanwen Huang
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430078, China
| | - Xinwen Zhao
- Wuhan Center of China Geological Survey, Wuhan, 430205, China
| | - Qinghua Li
- Wuhan Center of China Geological Survey, Wuhan, 430205, China
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9
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Yang H, Wang P, Chen A, Ye Y, Chen Q, Cui R, Zhang D. Prediction of phosphorus concentrations in shallow groundwater in intensive agricultural regions based on machine learning. CHEMOSPHERE 2023; 313:137623. [PMID: 36565764 DOI: 10.1016/j.chemosphere.2022.137623] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/08/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Excessive accumulation of phosphorus in soil profiles has become the main source of phosphorus in groundwater due to the application of phosphorus fertilizers in intensive agricultural regions (IARs). Elevated phosphorus concentrations in groundwater have become a global phenomenon, which places enormous pressure on the safe use of water resources and the safety of the aquatic environment. Currently, the prediction of pollutant concentrations in groundwater mainly focuses on nitrate nitrogen, while research on phosphorus prediction is limited. Taking the IARs approximately 8 plateau lakes in the Yunnan-Guizhou Plateau as an example, 570 shallow groundwater samples and 28 predictor variables were collected and measured, and a machine learning approach was used to predict phosphorus concentrations in groundwater. The performance of three machine learning algorithms and different sets of variables for predicting phosphorus concentrations in shallow groundwater was evaluated. The results showed that after all variables were introduced into the model, the R2, RMSE and MAE of support vector machine (SVM), random forest (RF) and neural network (NN) were 0.52-0.60, 0.101-0.108 and 0.074-0.081, respectively. Among them, the SVM model had the best prediction effect. The clay content and water-soluble phosphorus in soil and soluble organic carbon in groundwater had a high contribution to the prediction accuracy of the model. The prediction accuracy of the model with reduced number of variables showed that when the number of variables was equal to 6, the RF model had R2, RMSE and MAE values of 0.53, 0.108 and 0.074, respectively, and the number of variables increased again; there were small changes in R2, RMSE and MAE. Compared with the SVM and NN models, the RF model can achieve higher accuracy by inputting fewer variables.
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Affiliation(s)
- Heng Yang
- College of Resource and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Panlei Wang
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650201, China
| | - Anqiang Chen
- Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650201, China.
| | - Yuanhang Ye
- College of Resource and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Qingfei Chen
- College of Resource and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Rongyang Cui
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Chinese Academy of Sciences, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy, Chengdu, 610041, China; University of Chinese Academy of Science, Beijing, 100049, China
| | - Dan Zhang
- College of Resource and Environment, Yunnan Agricultural University, Kunming, 650201, China.
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Ren Y, Cao W, Li Z, Pan D, Wang S. Identification of arsenic spatial distribution by hydrogeochemical processes represented by different ion ratios in the Hohhot Basin, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:2607-2621. [PMID: 35932348 DOI: 10.1007/s11356-022-22311-6] [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: 04/08/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
The Hohhot Basin, a typical inland basin of the Yellow River Basin in China, has high concentrations of arsenic (As) in its shallow groundwater, while the factors dominating the distribution of high arsenic levels remain to be further identified. An analysis of the ratio of hydrogeochemical compositions can help to reveal the spatial characteristics of the shallow groundwater environmental conditions and the distribution of high-arsenic water (As >10 μg/L). In this study, a total of 170 samples of shallow groundwater in the Hohhot Basin were collected and water samples with As >10 μg/L accounted for 29.4% of the total. Based on the slope changes of the cumulative frequency curves of (HCO3- + CO32-)/SO42-, Ca2+/(HCO3- + CO32-), Ca2+/Mg2+, and Na+/Ca2+, the groundwater in the study area can be categorized into six different zones according to the environmental characteristics including redox condition, water recharge intensity, and cation exchange level. The result shows that the groundwater in the front of the piedmont alluvial plain and platform is in a weak reducing condition with high lateral recharge intensity, fast runoff, and weak cation exchange. In the Dahei River alluvial plain, which serves as the groundwater discharge zone, the groundwater runoff is sluggish with poor lateral recharge, sufficient exchange between cations in the groundwater and the aquifer matrix, and enhanced reducibility. The degree of oxidation increased in the groundwater near the Hasuhai Lake and the drainage canal, which adverse to the arsenic enrichment. High-arsenic groundwater is mainly distributed in aquifers of (HCO3- + CO32-)/SO42 > 10, Na+/Ca2+ > 13, and Ca2+/(HCO3- + CO32-) < 0.1, which represent the strong reducing condition, low surface water recharge intensity, and strong cation exchange condition. Reductive dissolution of iron oxide, strong evaporation and concentration process, and competition from phosphate in aquifers jointly lead to the release of arsenic into groundwater.
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Affiliation(s)
- Yu Ren
- Institute of Hydrogeology and Environmental Geology IHEG, Chinese Academy of Geological Sciences (CAGS), Shijiazhuang, 050061, Hebei, China
- Key Laboratory of Groundwater Science and Engineering, Ministry of Natural Resources, Shijiazhuang, 050061, China
- National Observation and Research Station on Groundwater and Land Subsidence of Cangzhou, Shijiazhuang, 050061, Hebei, China
| | - Wengeng Cao
- Institute of Hydrogeology and Environmental Geology IHEG, Chinese Academy of Geological Sciences (CAGS), Shijiazhuang, 050061, Hebei, China.
- Key Laboratory of Groundwater Science and Engineering, Ministry of Natural Resources, Shijiazhuang, 050061, China.
- National Observation and Research Station on Groundwater and Land Subsidence of Cangzhou, Shijiazhuang, 050061, Hebei, China.
| | - Zeyan Li
- Institute of Hydrogeology and Environmental Geology IHEG, Chinese Academy of Geological Sciences (CAGS), Shijiazhuang, 050061, Hebei, China
- Key Laboratory of Groundwater Science and Engineering, Ministry of Natural Resources, Shijiazhuang, 050061, China
- National Observation and Research Station on Groundwater and Land Subsidence of Cangzhou, Shijiazhuang, 050061, Hebei, China
| | - Deng Pan
- Henan Institute of Geological Environmental Monitoring, Zhengzhou, 450016, China
| | - Shuai Wang
- Henan Institute of Geological Environmental Monitoring, Zhengzhou, 450016, China
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