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Ma X, Guan DX, Zhang C, Yu T, Li C, Wu Z, Li B, Geng W, Wu T, Yang Z. Improved mapping of heavy metals in agricultural soils using machine learning augmented with spatial regionalization indices. JOURNAL OF HAZARDOUS MATERIALS 2024; 478:135407. [PMID: 39116745 DOI: 10.1016/j.jhazmat.2024.135407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/10/2024]
Abstract
The accurate spatial mapping of heavy metal levels in agricultural soils is crucial for environmental management and food security. However, the inherent limitations of traditional interpolation methods and emerging machine-learning techniques restrict their spatial prediction accuracy. This study aimed to refine the spatial prediction of heavy metal distributions in Guangxi, China, by integrating machine learning models and spatial regionalization indices (SRIs). The results demonstrated that random forest (RF) models incorporating SRIs outperformed artificial neural network and support vector regression models, achieving R2 values exceeding 0.96 for eight heavy metals on the test data. Hierarchical clustering for feature selection further improved the model performance. The optimized RF models accurately predicted the heavy metal distributions in agricultural soils across the province, revealing higher levels in the central-western regions and lower levels in the north and south. Notably, the models identified that 25.78 % of agricultural soils constitute hotspots with multiple co-occurring heavy metals, and over 6.41 million people are exposed to excessive soil heavy metal levels. Our findings provide valuable insights for the development of targeted strategies for soil pollution control and agricultural soil management to safeguard food security and public health.
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Affiliation(s)
- Xudong Ma
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Dong-Xing Guan
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chaosheng Zhang
- International Network for Environment and Health, School of Geography, Archaeology and Irish Studies, University of Galway, Ireland
| | - Tao Yu
- School of Science, China University of Geosciences, Beijing 100083, China
| | - Cheng Li
- Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, Guangxi 541004, China
| | - Zhiliang Wu
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Bo Li
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Wenda Geng
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Tiansheng Wu
- Guangxi Institute of Geological Survey, Nanning 530023, China
| | - Zhongfang Yang
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
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Shrestha G, Calvelo-Pereira R, Poggio M, Jeyakumar P, Roudier P, Kereszturi G, Anderson CWN. Predicting cadmium fractions in agricultural soils using proximal sensing techniques. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 349:123889. [PMID: 38574949 DOI: 10.1016/j.envpol.2024.123889] [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: 11/20/2023] [Revised: 02/20/2024] [Accepted: 03/27/2024] [Indexed: 04/06/2024]
Abstract
Cadmium (Cd) accumulation in agricultural systems has caused global environmental and health concerns. Application of phosphate fertiliser to sustain plant production unintentionally accumulated Cd in agricultural soils over time. Rapid and cost-effective Cd monitoring in these soils will help to inform Cd management practices. Compared to total Cd analysis, examining chemical fractions by sequential extraction methods can provide information on the origin, availability, and mobility of soil Cd, and to assess the potential plant Cd uptake. A total of 87 air-dried topsoil (0-15 cm) samples from pastoral farms with a history of long-term application of phosphate fertiliser were analysed using wet chemistry methods for total Cd and Cd forms in exchangeable, acid soluble, metal oxides bound, organic matter bound, and residual fractions. The data acquired using three proximal sensing techniques, visible-near-infrared (vis-NIR), mid-infrared (MIR), and portable X-ray fluorescence (pXRF) spectroscopy were used as input for partial least squares regression to develop models predicting total Cd and Cd fractions. The average total Cd concentration was 0.58 mg Cd/kg soil. For total Cd, cross-validation (cv) results of models using individual vis-NIR, MIR, and pXRF data performed with normalised root mean squared error (nRMSEcv) of 26%, 30%, and 31% and concordance correlation coefficient (CCCcv) of 0.85, 0.77, and 0.75, respectively. For exchangeable Cd, model using MIR data performed with nRMSEcv of 40% and CCCcv of 0.57. For acid soluble and organic matter bound Cd, models using vis-NIR data performed with nRMSEcv of 11% and 33% and CCCcv of 0.97 and 0.84, respectively. Reflectance spectroscopy techniques could potentially be applied as complementary tools to estimate total Cd and plant available and potentially available Cd fractions for effective implementation of Cd monitoring programmes.
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Affiliation(s)
- G Shrestha
- Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu Campus, Private Bag, 11222, Palmerston North, New Zealand; Manaaki Whenua - Landcare Research, Private Bag, 11052, Palmerston North, New Zealand
| | - R Calvelo-Pereira
- Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu Campus, Private Bag, 11222, Palmerston North, New Zealand.
| | - M Poggio
- Manaaki Whenua - Landcare Research, Private Bag, 11052, Palmerston North, New Zealand; AgroCares, Wageningen, the Netherlands
| | - P Jeyakumar
- Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu Campus, Private Bag, 11222, Palmerston North, New Zealand
| | - P Roudier
- Manaaki Whenua - Landcare Research, Private Bag, 11052, Palmerston North, New Zealand; Te Pūnaha Matatini, A New Zealand Centre of Research Excellence, Private Bag, 92019, Auckland, New Zealand
| | - G Kereszturi
- Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu Campus, Private Bag, 11222, Palmerston North, New Zealand
| | - C W N Anderson
- Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu Campus, Private Bag, 11222, Palmerston North, New Zealand
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Li Y, Zhang Y, Chen X, Liu Y, Li S, Liu H, Xu H. Enhanced cadmium phytoextraction efficiency of ryegrass (Lolium perenne L.) by porous media immobilized Enterobacter sp. TY-1. CHEMOSPHERE 2023; 337:139409. [PMID: 37406938 DOI: 10.1016/j.chemosphere.2023.139409] [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: 04/05/2023] [Revised: 06/06/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
Although studies on immobilized microorganisms have been conducted, their performance remains unclear for enhancing plants to remediate cadmium (Cd)-contaminated soil. In this study, a Cd-resistant strain TY-1 with good plant growth promotion traits was immobilized by biochar (BC) or oyster shell (OS) power to strengthen ryegrass to remediate Cd-contaminated soil. SEM-EDS combined with FTIR showed that TY-1 could tolerate Cd toxicity by surface precipitation, and functional groups such as hydroxyl and carbonyl groups might be involved. In the biocomposite treatments, soil pH increased, and the activity of fertility-related enzymes such as dehydrogenase increased by 109.01%-128.01%. The relative abundance of genus Saccharimonadales decreased from 7.97% to 3.35% in BS-TY and 2.61% in OS-TY, respectively. Thus, a suitable environment for ryegrass growth was created. The fresh weight, dry weight, plant height and Cd accumulation of ryegrass in TY treatment increased by 122.92%, 114.81%, 42.08% and 8.05%, respectively, compared to the control. Cd concentration in ryegrass was further increased in BC-TY and OS-TY by 24.14% and 40.23%, respectively. The improvement in soil microcosm and plant biomass forms an ongoing virtuous cycle, demonstrating that using carrier materials to improve the efficiency of microbial-assisted phytoremediation is realistic and feasible.
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Affiliation(s)
- Yongyun Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Yumei Zhang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Xianghan Chen
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Yikai Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Shiyao Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Huakang Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China; Key Laboratory of Environment Protection, Soil Ecological Protection and Pollution Control, Sichuan University & Department of Ecology and Environment of Sichuan, Chengdu, 610065, Sichuan, PR China.
| | - Heng Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China; Key Laboratory of Environment Protection, Soil Ecological Protection and Pollution Control, Sichuan University & Department of Ecology and Environment of Sichuan, Chengdu, 610065, Sichuan, PR China.
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Wu B, Li L, Guo S, Li Y. Source apportionment of heavy metals in the soil at the regional scale based on soil-forming processes. JOURNAL OF HAZARDOUS MATERIALS 2023; 448:130910. [PMID: 36736212 DOI: 10.1016/j.jhazmat.2023.130910] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/03/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Source apportionment is crucial to the prevention and control of heavy metals in the soil. The major methods focus on the identification of soil heavy metals from different pollution sources. However, they are unsuited to the source apportionment at a regional scale due to ignoring the spatial heterogeneity of heavy metal content caused by soil formation. Thus, we built a source apportionment model by introducing the weathering and leaching coefficients as the key parameters of soil-forming processes. In this study, we selected Liaohe Plain in China as the study area, which was the starting point of China's industrial development, with dense industrial areas and high levels of heavy-metal emission. Heavy metals concentrations in surface and deep soil of reference and grid points were collected as model data. The results showed that the average contribution rates of soil-forming process to Cd, Hg, As, and Pb were 82.7%, 85.2%, 88.6%, and 91.7%, respectively, and those of anthropogenic activities were 17.3%, 14.8%, 11.4%, and 8.3%, respectively. Spatial distribution of contribution rates showed the superposition of soil environmental background and pollution sources. This study provides a feasible method to quantify heavy metals contents from natural and anthropogenic sources at a regional scale.
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Affiliation(s)
- Bo Wu
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, PR China
| | - Linlin Li
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Shuhai Guo
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, PR China; National-Local Joint Engineering Laboratory of Contaminated Soil Remediation by Bio-physicochemical Synergistic Process, Shenyang 110016, PR China.
| | - Yang Li
- Liaoning Provincial Ecology & Environment Monitoring Center, Shenyang 110161, PR China
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Mu Y, Cui J, Liu A, Wang S, Shi Q, Wang J, Wei S, Zhang J. Interactions and quantification of multiple influencing factors on cadmium accumulation in soil-rice systems at a large region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163392. [PMID: 37044334 DOI: 10.1016/j.scitotenv.2023.163392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/14/2023]
Abstract
The accumulation of Cd in soil-rice systems at a large region is often extremely complicated due to environmental heterogeneity and the interactions of multiple influencing factors. However, the interactive effects and quantification of the contributions of influencing factors on Cd accumulation in large regions remain unclear. In this study, conditional inference trees and random forest analysis were used to identify the interactions of various factors (soil properties, topography and demographic-economic), and quantify their contributions to Cd accumulation in soil-rice systems of Sichuan-Chongqing region, China. The results showed that Cd content in the soil was the most significant influencing factor on Cd accumulation in soil-rice systems, especially bioavailable Cd in soil contributed to 35.73 % and 54.78 % for soil total Cd (Cdsoil) and brown rice Cd (Cdrice), respectively. Population density (PD) and elevation contributed 31.16 % and 27.40 % to Cdsoil content, respectively, and their interaction promoted the increase in Cdsoil content. Moreover, PD played a leading role in Cdsoil content when the elevation exceeded 324 m. The relative importances of slope and elevation for Cdrice content were 16.81 % and 8.49 %, respectively, and their interaction facilitated the increment of Cdrice content. As soil pH, gross domestic product (GDP) and slope decreased, the interaction of soil pH with GDP led to the increase of bioavailability factor (BAF), and that with slope enhanced the bioaccumulation factor (BCF). In addition, soil pH, PD and elevation were of considerable importance for the migration and transformation of Cd, with contributions of 22.11 %, 12.90 % and 12.52 % to BAF, and 5.05 %, 5.62 % and 5.50 % to BCF, respectively. This study is hopeful to provide a scientific insight into the prevention and control of Cd contamination in soil-rice systems at a large region.
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Affiliation(s)
- Yue Mu
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Jingxin Cui
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Andi Liu
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Shuai Wang
- Chongqing Agriculture Technical Extension Station, Chongqing 400121, PR China
| | - Qiujun Shi
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Jing Wang
- Technical Centre, Chongqing Customs, Chongqing 400020, PR China
| | - Shiqiang Wei
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Jinzhong Zhang
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400715, PR China.
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Li X, Li L, Zhou Z, Li T, An J, Zhang S, Xu X, Pu Y, Wang G, Jia Y, Liu X, Li Y. Soil potentially toxic element pollution at different urbanization intensities: Quantitative source apportionment and source-oriented health risk assessment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 251:114550. [PMID: 36652743 DOI: 10.1016/j.ecoenv.2023.114550] [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: 09/08/2022] [Revised: 12/20/2022] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Potentially toxic element (PTE) pollution of urban soils has become the focus of social concern, but the differences of the sources, pollution levels and source-oriented human health risks (HHR) of PTE in urban soils among different urban intensity areas is rarely known. This study explored a comprehensive scheme that combined positive matrix factorization model and source-oriented assessment to quantitatively assess the priority pollution sources and HHR in urban soils from areas with different urbanization intensities. All the average values for PTE concentrations, except for Cr, were higher than their corresponding background values. The contributions made by the four sources (atmospheric deposition, agricultural activities, traffic activities, and natural sources) were relatively similar (22.29-29.89%) in the low urbanization intensity (LUI) area, whereas traffic activities and atmospheric deposition made the greatest contributions in the medium urbanization intensity (MUI) (29.12%) and the high urbanization intensity (HUI) (38.97%) areas, respectively. The geo-accumulation index results revealed that Cd was the most polluting element and the HUI area had the highest pollution levels. The content-oriented assessment of HHR demonstrated that the non-carcinogenic risks were acceptable, but the carcinogenic risks were unacceptable. According to the source-oriented HHR assessment, among the anthropogenic activities, atmospheric deposition contributed the most to carcinogenic risk of children in all areas, and atmospheric deposition, traffic activities and agricultural activities contributed the most to the carcinogenic risk of adults in HUI, MUI and LUI, respectively. This suggest that control measures need to be tailored to the appropriate urbanization intensity to effectively curb PTE pollution caused by anthropogenic activities.
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Affiliation(s)
- Xinyun Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Lulu Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Zijun Zhou
- Institute of Agricultural Resources and Environment, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China.
| | - Ting Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
| | - Ji An
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Shirong Zhang
- College of Environmental Science, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiaoxun Xu
- College of Environmental Science, Sichuan Agricultural University, Chengdu 611130, China
| | - Yulin Pu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Guiyin Wang
- College of Environmental Science, Sichuan Agricultural University, Chengdu 611130, China
| | - Yongxia Jia
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiaojing Liu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Yun Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
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