1
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Liu JB, Zhang H, Wang H, He B, Wang H, Jin R, Tian T. Remediation of arsenic- and nitrate-contaminated groundwater through iron-dependent autotrophic denitrifying culture. ENVIRONMENTAL RESEARCH 2024; 257:119239. [PMID: 38810825 DOI: 10.1016/j.envres.2024.119239] [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: 02/23/2024] [Revised: 05/11/2024] [Accepted: 05/26/2024] [Indexed: 05/31/2024]
Abstract
Groundwater contamination with arsenic and nitrate poses a pressing concern for the safety of local communities. Bioremediation, utilizing Fe(II)-oxidizing nitrate reducing bacteria, shows promise as a solution to this problem. However, the relatively weak environmental adaptability of a single bacterium hampers practical application. Therefore, this study explored the feasibility and characteristics of a mixed iron-dependent autotrophic denitrifying (IDAD) culture for effectively removing arsenic and nitrate from synthetic groundwater. The IDAD biosystem exhibited stable performace and arsenic resistance, even at a high As(III) concentration of 800 μg/L. Although the nitrogen removal efficiency of the IDAD biosystem decreased from 71.4% to 64.7% in this case, the arsenic concentration in the effluent remained below the standard (10 μg/L) set by WHO. The crystallinity of the lepidocrocite produced by the IDAD culture decreased with increasing arsenic concentration, but the relative abundance of the key iron-oxidizing bacteria norank_f_Gallionellaceae in the culture showed an opposite trend. Metagenomic analysis revealed that the IDAD culture possess arsenic detoxification pathways, including redox, methylation, and efflux of arsenic, which enable it to mitigate the adverse impact of arsenic stress. This study provides theoretical understanding and technical support for the remediation of arsenic and nitrate-contaminated groundwater using the IDAD culture.
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Affiliation(s)
- Jia-Bo Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Hongbin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Hefei Wang
- National Marine Environmental Monitoring Center, Dalian, 116023, China.
| | - Banghui He
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Huixuan Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Ruofei Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Tian Tian
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
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2
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Zheng T, Hou J, Wu T, Jin H, Dai Y, Xu J, Yang K, Lin D. Ferric Oxide Nanomaterials and Plant-Rhizobacteria Symbionts Cogenerate Iron Plaque for Removing Highly Chlorinated Contaminants in Dryland Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11063-11073. [PMID: 38869036 DOI: 10.1021/acs.est.4c03133] [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: 06/14/2024]
Abstract
Rhizosphere iron plaques derived from Fe-based nanomaterials (NMs) are a promising tool for sustainable agriculture. However, the requirement for flooded conditions to generate iron plaque limits the scope of the NM application. In this study, we achieved in situ Fenton oxidation of a highly chlorinated persistent organic pollutant (2,2',4,5,5'-pentachlorobiphenyl, PCB101) through iron plaque mediated by the interaction between α-Fe2O3 NMs and plant-rhizobacteria symbionts under dryland conditions. Mechanistically, the coexistence of α-Fe2O3 NMs and Pseudomonas chlororaphis JD37 stimulated alfalfa roots to secrete acidic and reductive agents as well as H2O2, which together mediated the rhizosphere Fenton reaction and converted α-Fe2O3 NMs into iron plaque rich in Fe(II)-silicate. Further verifications reproduced the Fenton reaction in vitro using α-Fe2O3 NMs and rhizosphere compounds, confirming the critical role of •OH in the oxidative degradation of PCB101. Significant reductions in PCB101 content by 18.6%, 42.9%, and 23.2% were respectively found in stem, leaf, and soil after a 120-d treatment, proving the effectiveness of this NMs-plant-rhizobacteria technique for simultaneously safe crop production and soil remediation. These findings can help expand the potential applications of nanobio interaction and its mediated iron plaque generation for both agricultural practice and soil remediation.
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Affiliation(s)
- Tianying Zheng
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Jie Hou
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Ting Wu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Hui Jin
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Yunbu Dai
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Jiang Xu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Kun Yang
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Daohui Lin
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
- Zhejiang Ecological Civilization Academy, Anji 313300, China
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3
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Ning X, Long S, Liu Z, Dong Y, He L, Wang S. Vertical distribution of arsenic and bacterial communities in calcareous farmland amending by organic fertilizer and iron-oxidizing bacteria: Field experiment on concomitant remediation. JOURNAL OF HAZARDOUS MATERIALS 2024; 471:134415. [PMID: 38677113 DOI: 10.1016/j.jhazmat.2024.134415] [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: 01/10/2024] [Revised: 04/09/2024] [Accepted: 04/23/2024] [Indexed: 04/29/2024]
Abstract
The migration and transformation mechanisms of arsenic (As) in soil environments necessitate an understanding of its influencing processes. Here, we investigate the subsurface biogeochemical transformation of As and iron (Fe) through amended in the top 20 cm with iron oxidizing bacteria (FeOB) and organic fertilizer (OF). Our comprehensive 400-day field study, conducted in a calcareous soil profile sectioned into 20 cm increments, involved analysis by sequential extraction and assessment of microbial properties. The results reveal that the introduction of additional OF increased the release ratio of As/Fe from the non-specific adsorption fraction (136.47 %) at the subsoil depth (40-60 cm), underscoring the importance of sampling at various depths and time points to accurately elucidate the form, instability, and migration of As within the profile. Examination of bacterial interaction networks indicated a disrupted initial niche in the bottom layer, resulting in a novel cooperative symbiosis. While the addition of FeOB did not lead to the dominance of specific bacterial species, it did enhance the relative abundance of As-tolerant Acidobacteria and Gemmatimonadetes in both surface (39.2 % and 38.76 %) and deeper soils (44.29 % and 23.73 %) compared to the control. Consequently, the amendment of FeOB in conjunction with OF facilitated the formation of poorly amorphous Fe (hydr)oxides in the soil, achieved through abiotic and biotic sequestration processes. Throughout the long-term remediation process, the migration coefficient of bioavailable As within the soil profile decreased, indicating that these practices did not exacerbate As mobilization. This study carries significant implications for enhancing biogeochemical cycling in As-contaminated Sierozem soils and exploring potential bioremediation strategies. ENVIRONMENTAL IMPLICATION: The long-term exposure of sewage irrigation has potential adverse effects on the local ecosystem, causing serious environmental problems. Microorganisms play a vital role in the migration and transformation of arsenic in calcareous soil in arid areas, which highlights the necessity of understanding its dynamics. The vertical distribution, microbial community and fate of arsenic in calcareous farmland soil profile in northwest China were studied through field experiments. The results of this work have certain significance for the remediation of arsenic-contaminated soil in arid areas, and provide new insights for the migration, transformation and remediation of arsenic in this kind of soil.
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Affiliation(s)
- Xiang Ning
- Technoloy Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, China.
| | - Song Long
- Technoloy Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, China
| | - Zitong Liu
- Technoloy Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, China
| | - Yinwen Dong
- Technoloy Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, China
| | - Liang He
- Technoloy Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, China
| | - Shengli Wang
- Technoloy Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, China.
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4
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Liu Z, Ning X, Long S, Wang S, Li S, Dong Y, Nan Z. Arsenic and cadmium simultaneous immobilization in arid calcareous soil amended with iron-oxidizing bacteria and organic fertilizer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170959. [PMID: 38365035 DOI: 10.1016/j.scitotenv.2024.170959] [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: 10/03/2023] [Revised: 01/31/2024] [Accepted: 02/11/2024] [Indexed: 02/18/2024]
Abstract
Immobilization stands as the most widely adopted remediation technology for addressing heavy metal(loid) contamination in soil. However, it is crucial to acknowledge that this process does not eliminate pollutants; instead, it confines them, potentially leaving room for future mobilization. Presently, our comprehension of the temporal variations in the efficacy of immobilization, particularly in the context of its applicability to arid farmland, remains severely limited. To address this knowledge gap, our research delves deep into the roles of iron-oxidizing bacteria (FeOB) and organic fertilizer (OF) in the simultaneous immobilization of arsenic (As) and cadmium (Cd) in soils. We conducted laboratory incubation and field experiments to investigate these phenomena. When OF was combined with FeOB, a noteworthy transformation of available As and Cd into stable species, such as the residual state and combinations with Fe-Mn/Al oxides, was observed. This transformation coincided with changes in soil properties, including pH, Eh, soluble Fe, and dissolved organic carbon (DOC). Furthermore, we observed synergistic effects between available As and Cd when treated with bacteria and OF individually. The stabilization efficiency of As and Cd, as determined by the Toxicity Characteristic Leaching Procedure, reached its highest values at 33.39 % and 24.67 %, respectively, after 120 days. Nevertheless, the formation of iron‑calcium complexes was disrupted due to pH fluctuations. Hence, long-term monitoring and model development are essential to enhance our understanding of the remediation process. The application of organic fertilizer and the use of FeOB in calcareous soil hold promise for the restoration of polluted soil and the maintenance of soil health by mitigating the instability of heavy metals(loid).
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Affiliation(s)
- Zitong Liu
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Xiang Ning
- College of Ecology, Lanzhou University, Lanzhou 730000, People's Republic of China; Center for the Pan-third Pole Environment, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Song Long
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Shengli Wang
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China.
| | - Shengge Li
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Yinwen Dong
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Zhongren Nan
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
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5
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Chen Z, Wang S, Xu J, He L, Liu Q, Wang Y. Assessment and machine learning prediction of heavy metals fate in mining farmland assisted by Positive Matrix Factorization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 350:119587. [PMID: 38000273 DOI: 10.1016/j.jenvman.2023.119587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/24/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023]
Abstract
The accurate pollutant prediction by Machine Learning (ML) is significant to efficient environmental monitoring and risk assessment. However, application of ML in soil is under studied. In this study, a Positive Matrix Factorization (PMF) assisted prediction method was developed with Support Vector Machine (SVM) and Random Forest (RF) for heavy metals (HMs) prediction in mining farmland. Principal Component Analysis (PCA) and Redundancy Analysis (RDA) were selected to pretreat data. Experiment results illustrated Cd was the main pollutant with heavy risks in the study area and Pb was easy to migrate. The method effects of HMs total concentration predicting were PMF > Simple > PCA > PCA - PMF, and RF predicted better than SVM. Data pretreatment by RDA prior inspection improved the model results. Characteristic HMs Tessier fractions prediction received good effects with average R value as 0.86. Risk classification prediction performed good in Cd, Cu, Ni and Zn, however, Pb showed weak effect by simple model. The best classifier method for Pb was PMF - RF method with relatively good effect (Area under ROC Curve = 0.896). Overall, our study suggested the combination between PMF and ML can assist the prediction of HMs in soil. Spatial weighted attribute of HMs can be provided by PMF.
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Affiliation(s)
- Zhaoming Chen
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
| | - Shengli Wang
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
| | - Jun Xu
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
| | - Liang He
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
| | - Qi Liu
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
| | - Yufan Wang
- Technology Research Center for Pollution Control and Remediation of Northwest Soil and Groundwater, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
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6
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Irshad MK, Zhu S, Javed W, Lee JC, Mahmood A, Lee SS, Jianying S, Albasher G, Ali A. Risk assessment of toxic and hazardous metals in paddy agroecosystem by biochar-for bio-membrane applications. CHEMOSPHERE 2023; 340:139719. [PMID: 37549746 DOI: 10.1016/j.chemosphere.2023.139719] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/21/2023] [Accepted: 08/01/2023] [Indexed: 08/09/2023]
Abstract
Toxic and carcinogenic metal (loid)s, such arsenic (As) and cadmium (Cd), found in contaminated paddy soils pose a serious danger to environmental sustainability. Their geochemical activities are complex, making it difficult to manage their contamination. Rice grown in Cd and As-polluted soils ends up in people's bellies, where it can cause cancer, anemia, and the deadly itai sickness. Solving this issue calls for research into eco-friendly and cost-effective remediation technology to lower rice's As and Cd levels. This research delves deeply into the origins of As and Cd in paddy soils, as well as their mobility, bioavailability, and uptake mechanisms by rice plants. It also examines the current methods and reactors used to lower As and Cd contamination in rice. Iron-modified biochar (Fe-BC) is a promising technology for reducing As and Cd toxicity in rice, improving soil health, and boosting rice's nutritional value. Biochar's physiochemical characteristics are enhanced by the addition of iron, making it a potent adsorbent for As and Cd ions. In conclusion, Fe-BC's biomembrane properties make them an attractive option for remediating As- and Cd-contaminated paddy soils. More efficient mitigation measures, including the use of biomembrane technology, can be developed when sustainable agriculture practices are combined with these technologies.
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Affiliation(s)
- Muhammad Kashif Irshad
- Department of Environmental Sciences, Government College University Faisalabad, Pakistan; Department of Environmental and Energy Engineering, Yonsei University, Wonju, 26493, Republic of Korea
| | - Sihang Zhu
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing, China; Agricultural Management Institute, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Wasim Javed
- Punjab Bioenergy Institute, University of Agriculture Faisalabad, Pakistan
| | - Jong Cheol Lee
- Department of Environmental and Energy Engineering, Yonsei University, Wonju, 26493, Republic of Korea
| | - Abid Mahmood
- Department of Environmental Sciences, Government College University Faisalabad, Pakistan
| | - Sang Soo Lee
- Department of Environmental and Energy Engineering, Yonsei University, Wonju, 26493, Republic of Korea.
| | - Shang Jianying
- Department of Soil and Water Sciences China Agricultural University, Beijing, China.
| | - Gadah Albasher
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Atif Ali
- Department of plant breeding and genetics, University of Agriculture, Faisalabad, Pakistan
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7
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Long S, Ning X, Wang S, Xu J, Wu Y, Liu Z, Nan Z. Remediation of arsenic-contaminated calcareous agricultural soils by iron-oxidizing bacteria combined with organic fertilizer. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:68258-68270. [PMID: 37119488 DOI: 10.1007/s11356-023-27217-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 04/21/2023] [Indexed: 05/27/2023]
Abstract
In arid soil with low-iron and high-calcium carbonate contents, the fate of arsenic (As) is mainly controlled by the contents of calcium and organic matter in the soil. However, there is still a lack of knowledge about their interaction and that effect on their absorption by maize. The purpose of this study was to explore the long-term immobilization and repair mechanism of in situ As-contaminated farmland. We designed three treatments: iron-oxidizing bacteria (FeOB), organic fertilizer, FeOB and organic fertilizer added in combination. After 140-day field farmland remediation trial, the results showed that the FeOB can effectively immobilize the water-soluble As (FS1) in soil, and the organic fertilizer promoted the remediation of FeOB. In addition, the content of As in maize grains was reduced after treatment by FeOB and organic fertilizer. The XRD and XPS analysis of the topsoil showed that the combined treatment of FeOB and organic fertilizer promoted the formation of calcium arsenate mineral with low solubility and high stability; As(III) would gradually transform into As(V). The biological iron (hydr)oxide can increase the contents of Fe and As in the rhizosphere and form iron plaques on the surface of the roots by SEM-EDS analysis of maize root. Collectively, these results clarify the main biogeochemical ways to control the fate of As in calcareous soils with low-iron and low-organic matter contents and provide a basis for in situ remediation of As.
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Affiliation(s)
- Song Long
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China
| | - Xiang Ning
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China
| | - Shengli Wang
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China.
| | - Jun Xu
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China
| | - Yining Wu
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China
| | - Zitong Liu
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China
| | - Zhongren Nan
- College of Earth and Environmental Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, China
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8
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Ning X, Wang S, Long S, Dong Y, Li L, Nan Z. Temporal distribution and accumulation pattern of cadmium and arsenic in the actual field calcareous soil-maize system, northwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:162012. [PMID: 36737027 DOI: 10.1016/j.scitotenv.2023.162012] [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: 07/04/2022] [Revised: 01/04/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
The contrasting chemical behaviors of two toxic elements, arsenic (As) and cadmium (Cd) in co-contamination calcareous soil and its absorption by crops have not been thoroughly explored, especially in the implementation of the measure of prohibiting the use of wastewater to irrigate farmland. We propose that the present environmental characteristics of ecologically fragile areas and appropriate restoration measures are critical determinant of soil remediation. In this study, the typical field farmland irrigated by industrial and domestic wastewater in the Chinese Loess Plateau for >50 years was selected. The results showed that after the sewage irrigation was stopped, the mean contents of Cd (7.09 mg/kg) and As (13.47 mg/kg) in the soil were still rising, which might be a potential input source. The average values of soil risk indices such as the potential ecological risk (PERI = 2394), pollution load index (PLI > 4 for 60 % of studied samples), and degree of contamination (Dc = 86.6) showed severe soil pollution in the study area. The decrease of soil pH, the loss of soil texture and calcium carbonate were found to be the reasons for the high chemical activity of Cd. The bioconcentration factors (< 0.2) and translocation factor (> 1.0) of Cd indicate that corn is an excluder plant and an ideal phytoremediation method. Thus, 20 % of studied samples were higher than maximum permitted levels of Cd in grain, indicating potential related health hazards. On the contrary, As was mainly adsorbed in calcareous soil, and its bioavailability was lower compared with Cd. The difference between DTPA extraction and sequential extraction may be due to the transformation of chemical forms, resulting in unstable fractions increased the bioavailability of toxic elements. Overall, the findings provide new insights for solutions to manage and repair farmlands under the post-wastewater irrigation period.
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Affiliation(s)
- Xiang Ning
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Shengli Wang
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China.
| | - Song Long
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Yinwen Dong
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Longrui Li
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Zhongren Nan
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
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9
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Peng Y, Gu X, Yan P, Sun S, Zhang M, Tang L, He S. Mixotrophic denitrification improvement in ecological floating bed: Interaction between iron scraps and plant biomass. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 861:160718. [PMID: 36481157 DOI: 10.1016/j.scitotenv.2022.160718] [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] [Received: 09/26/2022] [Revised: 11/22/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
In this study, an iron scrap (IS)-based ecological floating bed was constructed to couple with plant biomass (FeB-EFB) for treating low-polluted water, and the nitrogen removal performance and mechanism were explored. The results showed that the nitrogen could be effectively removed in FeB-EFB, and the nitrate removal efficiency was 29.14 ± 8.06% even at a low temperature (13.9 ± 2.2 °C). After the temperature rose to 20.0 ± 0.9 °C, the denitrification rate was increased by 0.63 ± 0.16-0.81 ± 0.27 g/(m2 d) due to the synergistic effect of ISs and plant biomass. Plant biomass could promote the ISs release efficiency, while ISs could facilitate plant biomass availability by promoting cellulose decomposition. High-throughput sequencing analysis revealed that the iron-oxidizing bacteria Pseudomonas were the dominant genus in FeB-EFB. Meanwhile, the existence of plant biomass could increase the abundance of iron-related bacteria and enrich heterotrophic and facultative denitrifying bacteria (e.g., Hydrogenophaga, Comamonas) as well, improving iron-mediated denitrification and heterotrophic denitrification simultaneously. Therefore, mixotrophic denitrification improvement played a major role in promoting nitrogen removal of FeB-EFB. These results indicated that coupling iron scraps with plant biomass may be an effective way to improve the nitrogen removal performance of EFB.
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Affiliation(s)
- Yuanyuan Peng
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Xushun Gu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Pan Yan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Shanshan Sun
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Manping Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Li Tang
- Shanghai Gardens (Group) Co., Ltd., Shanghai 200335, PR China
| | - Shengbing He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China.
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10
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Xu J, Chen Z, Li Y, Dong S, Li L, Long S, Wu Y, Wang S. The changes in the physicochemical properties of calcareous soils and the factors of arsenic (As) uptake by wheat were investigated after the cessation of effluent irrigation for nearly 20 years. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160171. [PMID: 36379339 DOI: 10.1016/j.scitotenv.2022.160171] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/31/2022] [Accepted: 11/09/2022] [Indexed: 06/16/2023]
Abstract
It is not known what the buffering capacity of soils and arsenic (As) enrichment by crops is for calcareous agricultural soils after the end of long-term effluent irrigation. In this study, changes in soil physicochemical properties and factors of influencing As uptake by wheat were investigated in agricultural soils where sewage irrigation had been ceased for nearly 20 years. The results showed that the content of CaCO3 and pH in soil increased compared to the period before the cessation of sewage irrigation, but remained below the soil background value. Furthermore, CaCO3 is by far the main buffering substance in agricultural soils and indirectly contributes to the increase in pH. The As concentration in the soil was 36.4 ± 34.8 mg/kg, which was 0.56-10.28 times and 0.28-5.18 times higher than the soil background and risk screening values, respectively, but showed a decreasing trend. pH and Fe dissolution were the main reasons for the lower As concentration in the soil. Total As in soil was a better predictor of As in wheat, and soil electrical conductivity (EC) and soil organic matter (SOM) promoted As uptake by wheat. The competitive uptake of As by dissolved Si was an important reason for the mismatch between As concentrations in soil and wheat. This study highlighted the key issues of As transport transformation in soil-wheat systems after cessation of effluent irrigation, using agricultural soils, and provided a reference for soil risk management in agricultural soils in mining areas.
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Affiliation(s)
- Jun Xu
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Zhaoming Chen
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Yueyue Li
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Suhang Dong
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Longrui Li
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Song Long
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Yining Wu
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Shengli Wang
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
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Ning X, Wang S, Long S, Li L, Dong S, Nan Z. The role of Fe-oxidizing bacteria (FeOB) and organic matters in As removal in the heavy-polluted arid soil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 245:114126. [PMID: 36183429 DOI: 10.1016/j.ecoenv.2022.114126] [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: 04/29/2022] [Revised: 09/04/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
The bio-remediation of As-polluted farmlands in the arid area is seldomly reported. This study aimed at understanding the impact of DOM, Fe-oxides, and FeOB biogeochemical processes on As remediation. The approaches used included: FeOB strain Pseudomonas flavescens LZU-3; Batch-experiment. Our results showed that all FeOB tested effectively immobilized As (>95%) during microbial mineralization; DOM play an important role in the reduction of Fe(III)(hydr)oxides and As(V); Less-crystallized ferrihydrite transform to more-crystallized goethite and secondary minerals; Under the reaction of FeOB and DOM, the As-Fe-OM ternary compound were formed, containing N, S, C and O functional group; The addition of OM can clearly reduce soil Eh, promoting dissolution of As in bound to iron oxides, co-precipitation of the amorphous iron oxide in Fe(III)-OM-FeOB, closely related to As in bound to insoluble organics and sulfides and mineral residues, which plays an important role in controlling the mobilization of As. This study provides controlling of As transportation and transformation in the As-DOM-Bio-Fe ternary system as As-remediation technology in the arid soil.
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Affiliation(s)
- Xiang Ning
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, the People's Republic of China
| | - Shengli Wang
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, the People's Republic of China.
| | - Song Long
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, the People's Republic of China
| | - Longrui Li
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, the People's Republic of China
| | - Suhang Dong
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, the People's Republic of China
| | - Zhongren Nan
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, the People's Republic of China
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