Heavy Metals In Soil Research Articles

Effects of geographical and soil factors on soilś arsenic levels: a case study in typical arsenic-contaminated paddy fields based on machine learning.

Heavy metal pollution in agricultural land has emerged as a contemporary environmental issue of prominent concern. The concentration of heavy metals in soil is influenced not only by inherent soil properties but also by geographical factors. Moreover, the identification of its influencing factors is challenging because of the intricate interactive effects among them. Previous studies primarily focused on single-factor identification and spatial distribution characterization, neglecting the characteristics and spatial features of soil heavy metal concentration under the interactive effects of geographical factors and soil properties. This study assessed the influence of geographical factors, soil properties, and their interactive effects on the spatial distribution of soil arsenic (As), in a typical arsenic-contaminated paddy field area by employing machine learning, analysis of variance, and spatial analysis methods. The findings show that the prediction performance (R2) of the random forest model for soil As concentration was 0.596, and the primary factors influencing the distribution of soil As are elevation, roads, rivers, soil pH, and cation exchange capacity (CEC). Moreover, the interactive effect between elevation and soil CEC had a significant effect on soil As (p < 0.05), exhibiting spatially homogeneous characteristics. The interactive effect between rivers and both soil pH and soil CEC exhibited spatially heterogeneous effects on soil As (p < 0.1). Additionally, the interactive effect between roads and soil pH affected soil As (p < 0.05), with spatially homogeneous characteristics. By identifying the main influencing factors of As in paddy soil, this study further explores the variation characteristics of soil As concentration under the interactive effects of geographical factors and soil properties. These insights can serve as a valuable reference for the precise prevention of As pollution in paddy field area.

Source apportionment, criteria derivation, and health risk assessment of heavy metals in urban green space soils.

Urban green spaces play a crucial role in maintaining urban resilience and offering opportunities for outdoor activities to residents. The potential hazards of heavy metals in the soils of these green spaces have raised significant concerns. A total of 130 topsoil samples containing seven heavy metals were collected from 50 urban green spaces in Tianjin, China. The study aimed to identify and quantify the potential sources of these heavy metals, establish general assessment criteria (GAC) for the metals, and evaluate the associated human health risks based on their concentration and sources. The findings indicated minimal pollution from heavy metals in the soils of Tianjin's urban green spaces. Through the use of positive matrix factorization (PMF), correlation analysis, and spatial interpolation, the study identified four main sources of heavy metals: traffic emissions, natural sources, industrial activities, and agricultural activities. Discrepancies between the contaminated land exposure assessment (CLEA) model-derived GAC and China's soil screening values were attributed to differences in land use scenarios. Moreover, concentration-specific health risk assessments revealed that protection area green spaces posed a higher risk to human health compared to park green spaces. The study also highlighted that natural factors correlated with cobalt and agricultural activities related to arsenic significantly contributed to non-carcinogenic risks in both adults and children. Arsenic-related agricultural activities were identified as key contributors to carcinogenic risks in children. The findings of this study are valuable for establishing soil quality standards, and provide a reference for the prevention and control of heavy metal pollution in urban greenfield soils as well as for the protection of the health of urban populations.

Assessment the impact of palygorskite modified by chlorides on speciation and environmental risk of heavy metals in soil contaminated

This study aims to evaluate the effectiveness of palygorskite (PAL) modified with various chlorides (PMNaCl), (PMCaCl2), (PMMgCl2), (PMFeCl3) and (PMAlCl3) in stabilizing Cu and Ni in contaminated soils. Characterization methods involving Scanning Electron Microscopy (SEM), X-ray deflection (XRD and Fourier Transform Infrared Spectroscopy (FT-IR) were used to characterize the effects of palygorskite on the chemical functional groups of chloride stick and the construction of stabilizers. The Diethylene Triamine Pentaacetic Acid (“DTPA extraction”) and Toxicity Characteristic Leaching Procedure (TCLP) were conducted to assess the bioavailability and mobility of Cu and Ni in soil with PAL-modified chlorides. The germinated index (GI) was employed to examine and analyze the microstructure and physico-chemical properties of the contaminated soil. The residue speciation concentration enhanced substantially, illustrating that the heavy metal speciation had stabilized after being with PAL-modified chloride. After the amendment of the PAL-modified chlorides the soil pH was enhanced by 1.33 units, whereas Electrical Conductivity (EC) increased significantly (P < 0.05) from 2.61 to 4.95 µS cm-1, Cation Exchange Capacity (CEC) increased significantly (P < 0.05) from 11.50 to 13.00 cmol/kg, while the available potassium (K) was significantly (P < 0.05) increased from 51.67 to 69.30, and the available phosphate (P) was significantly (P < 0.05) increased from 0.38 to 0.63. The most significant Sequential Extraction Procedure (BCR) in residual fraction for Cu and Ni in soil treated by PMFC and PMMC were significantly (P < 0.05) increased by 37.37% and 39.33%, respectively. Our findings indicate that PAL-modified chlorides significantly stabilize heavy metals in soil, making them promising candidates for soil remediation.

Mitigating effect of γ-aminobutyric acid and gibberellic acid on tomato plant cultivated in Pb-polluted soil

Soil heavy metal pollution poses a significant environmental risk to human health and plant growth. Gibberellic acid (GA) and γ-aminobutyric acid (GABA) are effective methods for resolving this issue. GA regulates growth mechanisms such as seed germination, flowering, and stem elongation. Plants use GABA, a signaling molecule, to control physiological processes, growth, and responses to stress. This substance plays a crucial role in the interactions between hormones and plant defense, as evidenced by its effects on photosynthesis, food absorption, and stomatal behavior. The study aimed to determine how GABA and GA amendments affected tomato plants under no toxicity and Pb toxicity. The study included four treatments (0, GA, GABA, and GA + GABA) in four replications following a completely randomized design. Notably, the GA + GABA treatment led to considerable enhancements in fresh weight (88.98%), dry weight (68.28%), shoot length (39.98%), and root length (115.43%) compared to the control under Pb toxicity. Moreover, GA + GABA treatment significantly increased tomato chlorophyll a (161.72%), chlorophyll b (93.33%), and total chlorophyll content (112.45%) under Pb stress toxicity, confirming the effectiveness of GA + GABA treatment. In conclusion, GA + GABA is recommended as the best amendment to mitigate Pb stress in tomato plants. Our findings have broader implications for GA + GABA application, offering a potential technology to enhance sustainable crop production by improving plant growth and yield in Pb-contaminated soils. More investigations are suggested at field levels under different agroclimates on different crops for the declaration of GA + GABA as the best amendment for alleviating different heavy metal pollutions and sustainable agriculture productions.

Assessment of ecological and human health risks of heavy metals in soils and Polygonatum sibiricum plants from various cultivation areas in China.

In this study, we collected 528 samples from 7 important Polygonatum sibiricum (P. sibiricum) planting areas in China. The P. sibiricum samples were classified into P. sibiricum Red., P. cyrtonema Hua. and P. kiugianum Col.et Hemsl. The content of the Cu, As, Zn, Cd, Pb, and Cr in P. sibiricum and soil were determined using inductively coupled plasma mass spectrometry, and the ecological and health risks were evaluated. The results showed that addition to Cu, the soil exhibits varying degrees of excessive pollution from Zn, As, Pb, Cd, and Cr exceeding permissible levels (GB15618 - 2018, Soil environmental quality-Risk control standard for soil contamination of agricultural land in China). Among them, 31.56% Zn, 22.43% As, and 22.05% Cd in soil exceeded the GB 15618 - 2018 standard. Additionally, three types of P. sibiricum soil have risks, with the risk level being P. cyrtonema Hua. > P. kiugianum Col.et Hemsl. > P. sibiricum Red. It was worth noting that the practice of artificial cultivation management may reduce the amount of As, Cd, and Cr in the soil while increasing the amount of Zn. The order of P. sibiricum bioaccumulating ability in different heavy metals was: Cd > Zn > Cu > Cr > As > Pb, and it had good tolerance to As, Pb, and Cr. In addition, the chronic daily intake, hazard quotient and hazard indexes indicate that the current Cu, Hg, As, Cd and Pb contents of P. sibiricum in China do not pose a health risk to humans. In summary, the impact of Cd in P. sibiricum should be given attention.

Heavy metal accumulation and transfer between soils-plants-goats in a Mo-mining area.

The effect of Mo mining on soil-plant-animal ecosystem heavy metal accumulation and migration has not been well investigated. In this work, soil, native plants, and goat hair samples were collected from mining, urban, and rural areas near a Mo-mining area in Luanchuan, China and analyzed for Mo, Pb, Cd, Cu, Zn, Ni, and Mn concentrations. Molybdenum had the largest pollution indices (soil heavy metal concentration/background value) among all metals. Although mining area soil had greater concentrations of all seven metals as compared to urban and rural areas, significant differences were only found for Cd (mining, 2.54; urban, 1.59; and rural, 1.85mg kg-1), Cu (73.4, 32.1, and 32.6mg kg-1), and Mo (109, 33.6, and 16.6mg kg-1). Setaria viridis had greater Mo concentrations in the mining area than the urban area, most plant samples had Mo concentrations >5mg kg-1, and mean plant Cu:Mo ratios were <4 in all three areas, both indicating potential Mo toxicity and Cu deficiency risks to herbivores. Goat hair Mo concentrations in both areas were greater, whereas the Cu:Mo ratios were lower than those found in the literature. Plants had greater bioconcentration factors (0.840-5.30) for soil Mo than other metals, whereas goat hair and grass Mo concentration ratios were<0.03, lower than most reported literature values. Results indicate Mo accumulation in soil, plants, and goat hair in the Mo-mining area; remediation measures may be needed to alleviate animal and potentially resident Mo stress.

Struvite-loaded biochar beads fertilizer for different soils: nutrient slow release, soil properties improvement and heavy metal remediation

Struvite-loaded biochar beads fertilizer for different soils: nutrient slow release, soil properties improvement and heavy metal remediation

Assessment of the sources and health risks of heavy metals in the soil-rice system based on positive matrix factorization and Monte Carlo simulation

In recent years, the harmful effects of heavy metal pollution in soil and rice on public health have garnered widespread attention. However, most studies focus only on the evaluation of heavy metal pollution in either soil or rice, often overlooking the fact of the combined effects of heavy metal pollution. We conducted an integrated assessment of the heavy metal pollution levels in both soil and rice. This study examined eight common heavy metals (Cd, Ni, As, Cu, Hg, Pb, Cr, and Zn) within the soil-rice system of Wanzhou District, Chongqing City. We employed Positive Matrix Factorization and Monte Carlo simulation to identify the sources of soil pollution and assess associated health risks. The findings revealed an average Impact Index of Comprehensive Quality (IICQ) value of 3.60 for the soil-rice system, indicating a pollution level exceeding “slight pollution”. The primary contributors to soil heavy metal contamination were identified as metal smelting and processing, pesticide and fertilizer use, manure application, geological background and rock weathering, agricultural activities, and coal combustion. Among the assessed metals, As, Cr, Cd, and Ni posed the greatest health risks and should be prioritized for monitoring and control. Given the heightened health risks associated with prolonged consumption of rice contaminated by heavy metals, addressing pollution in the agricultural soil-rice system is an urgent necessity.

Assessing the Sources and Risks of Heavy Metals in Agricultural Soils: A Comprehensive Review

Heavy metals in agricultural soils pose a significant environmental and health risk, impacting both soil quality and food safety. These contaminants primarily originate from anthropogenic sources, such as industrial activities, improper waste disposal, and the excessive use of pesticides and fertilizers. Natural sources, including mineral weathering, also contribute to the accumulation of heavy metals in soil. Influencing factors, such as soil pH, organic matter content, and climate conditions, can affect the mobility and bioavailability of these metals, exacerbating the risks. The primary heavy metals of concern include lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg), and chromium (Cr) (di pa sure to mga heavy metals), which can accumulate in the food chain through crop uptake. Understanding the sources, distribution, and influencing factors of heavy metals is crucial for mitigating risks associated with their presence in agricultural soils. Effective management strategies, including soil remediation, controlled use of fertilizers, and monitoring programs, are essential for reducing the exposure of both humans and ecosystems to these toxic metals.

Spatial Distribution, Influencing Factors, Risk Assessment, and Source Analysis of Heavy Metals in Soil Profile of Farmland in the Guanzhong Plain

In order to understand the spatial distribution, influencing factors, ecological risk characteristics, and sources of heavy metals in the soil profile （0-1 m） of farmland in the Guanzhong Plain, soil samples of 0-1 m were collected from 124 sites in the Guanzhong Plain. The contents of heavy metals （As, Cd, Cr, Cu, Ni, Pb, and Zn） in soil were analyzed at different depths （0-10 cm, 10-20 cm, 20-40 cm, 40-60 cm, and 60-100 cm）. The study generated the spatial distribution characteristics of soil heavy metals based on geostatistics and investigated the influencing factors of heavy metals based on structural equation modeling （SEM）. In addition, the ecological environmental risks of soil heavy metals were evaluated using the methods of index of geo-accumulation （Igeo）, single factor contaminant index （Pi）, and potential ecological risk index （Ei）. Finally, the sources of soil heavy metals were analyzed using the PMF model. The results showed that the average heavy metal content of ω（As）, ω（Cd）, ω（Cr）, ω（Cu）, ω（Ni）, ω（Pb）, and ω（Zn） in the 0-10 cm were 19.57, 0.71, 69.65, 21.91, 28.67, 17.54, and 73.77 mg·kg-1, respectively. The average values of As, Cd, Cr, Pb, and Zn exceeded the background values. With the increasing soil depth, all heavy metals showed a decreasing trend except for Cd and Ni. The spatial distribution indicated that different heavy metals in the same soil layer had different spatial distributions, and the spatial distribution of heavy metals also varied at different depths. The structural equation model showed that the factors affecting the distribution of heavy metals at different depths were deeply dependent. The ecological risk assessment showed that Cd at different depths had higher ecological risks, while the rest were considered minor risks. The sources of 0-40 cm soil layer were consistent, and the main sources were pesticides and herbicides, organic fertilizers and fertilizers, natural sources, and traffic-induced atmospheric subsidence and industrial sources； the sources of 40-100 cm were consistent, and the main sources were pesticides and herbicides, organic fertilizers and fertilizers, natural sources, and traffic-induced atmospheric subsidence.

Source Apportionment and Ecological Risk of Soil Heavy Metals in Typical Vanadium-titanium Magnetite Mining Areas Affected by Intensive Transportation Activities in Chengde

A total of 895 surface soil samples （0-20 cm） and five road-dust samples were collected in a typical vanadium-titanium magnetite mining area of Hongqi-Damiao catchment in the Chengde City and analyzed for 12 heavy metals （Cu, Ni, Cd, Cr, Pb, Zn, Hg, V, Ti, Mn, As, and Co） and their chemical speciation. The accumulation and ecological risk characteristics of soil heavy metals （HMs） were clarified by geological accumulative index, potential ecological risk index （RI）, risk assessment coding （RAC）, and modified Nemerow integrated ecological risk index （mNIER）. Multiple statistical methods including principal component analysis, correlation analysis, cluster analysis, redundancy analysis, and GIS spatial analysis were used to investigate the spatial variation response of soil HMs to the environmental impact factors （distance to the road network, land use, and soil parent material types）. The sources of HMs were quantitatively analyzed using a positive matrix factorization （PMF） model. The results showed that the over-standard rates of Cu, Cr, Cd, Ni, Pb, and Zn were 5.70%, 2.79%, 1.01%, 0.67%, 0.11%, and 0.11%, respectively, in comparison to China's soil environmental quality standard risk screening values （GB15618-2018）. The average accumulation index of soil HMs followed the order of Cu&gt;Ti&gt;Cr&gt;V&gt;Co&gt;Ni&gt;Cd&gt;Zn&gt;Mn&gt;As&gt;Hg&gt;Pb, while the average accumulation index of Cu was 1.23 and categorized as moderate accumulation. The accumulation of Cu, Zn, Cr, Mn, V, Ti, Co, and Ni gradually decreased within a distance of 200 m, while the content of Cd in soil was relatively stable within the distance from 25 m to 800 m to the road network, and the accumulation index of Pb, Hg, and As in soil was highest at the 200 m buffer zone. The average RAC value of 12 HMs followed the order of Cd&gt;Mn&gt;Ni&gt;Zn&gt;Hg&gt;Co&gt;Pb&gt;Cu&gt;As&gt;Cr&gt;V&gt;Ti. The average RAC value of the Cd element was 46.45%, showing high biological activity, while the bioavailability RAC value of other elements was generally categorized as low-risk or risk-free level. The potential ecological risk of HMs in soil was relatively low with the RI value range between 51.48 to 1 152.39 （average of 131.2） and the mNIER value range between 10.32 to 745.57, with an average value of 32.85, in which 97.43% of the samples were classified as light to moderate risk. Based on the PMF model, 44.82%, 33.45%, 32.27%, and 24.35% of Pb, Hg, Cd, and Zn in surface soil were contributed by intensive transportation activities, respectively. The main sources of 12 HMs in the study area were the combined sources of natural sources （soil parent materials）, weathering sources of V-Ti-Fe-P deposits, dust deposition from industrial and mining activities and coal combustion, agricultural sources, and traffic sources, with their contribution rates of 27.46%, 21.12%, 19.29%, 17.05%, and 15.08%, respectively.

Accumulation Characteristics, Pollution Risk, and Source Analysis of Soil Heavy Metals Around a Coal Mining Area in the Baiyin Section of the Upper Yellow River

To quantitatively assess and accurately ascertain the characteristics, sources, and ecological risks of soil heavy metal pollution in the arid and semi-arid coal mining areas of the upper Yellow River Basin, the Wangjiashan coal mining area in Pingchuan of the Baiyin City was selected for this study. Based on the concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the soils of the urban areas and agricultural lands around the coal mining region, the geo-accumulation index, enrichment factor, modified Nemerow comprehensive pollution index, and comprehensive ecological risk index were employed to systematically quantify the levels of soil heavy metal pollution and associated ecological risks. Furthermore, cluster analysis and the positive matrix factorization receptor model were jointly utilized to quantitatively explore the sources of soil heavy metals and their respective contribution rates. The results showed： ① The contents of the eight heavy metals in the urban soils around the study area were below the risk screening values for Type I construction land in the "Soil Environmental Quality Risk Control Standard for Soil Pollution of Construction Land （Trial）" （GB 36600-2018）. However, the contents of Pb, Hg, Cd, Zn, Cu, As, and Cr exceeded the soil background values of Gansu Province in 100%, 88.89%, 44.44%, 22.22%, 16.67%, 13.89%, and 2.78% of the samples, respectively. The contents of the eight heavy metals in the agricultural soils were below the screening values for soils with pH &gt; 7.5 in the "Soil Environmental Quality Risk Control Standard for Soil Pollution of Agricultural Land （Trial）" （GB 15618-2018）. Yet, the concentrations of Pb, Hg, Cd, Cu, Zn, As, and Ni exceeded the soil background values of the Gansu Province in 100%, 89.74%, 38.46%, 25.64%, 23.09%, 23.08%, and 17.95% of the examined samples, respectively. ② The soil pollution in the surrounding areas was predominantly characterized by Hg and Pb, overall presenting a moderate level of contamination. However, the degree of comprehensive pollution in urban soils exceeded that of agricultural soils. The urban soils were in a state of relatively high ecological risk, whereas the agricultural soils exhibited a moderate ecological risk. Notably, Hg was the principal hazardous element contributing to the ecological risk of the soils around the study area. ③ In the surrounding soils, the presence of As was impacted by coal combustion-agricultural sources and natural sources, contributing 40.73% and 26.68%, respectively. Cd originated from industrial and transportation sources, with contribution rates of 37.07% and 26.17%, respectively. Cr was affected by natural sources at 35.37%. Cu and Zn were influenced by the combined effects of coal combustion-agricultural sources and transportation sources, with respective contribution rates of 29.94% and 41.19% for Cu and 31.41% and 40.32% for Zn. Hg was predominantly influenced by coal mining activities, accounting for 99.99% of its source.

Assessing the environmental capacity of heavy metals in soil: the example of Yushu City, Qinghai Province

Assessing the environmental capacity of heavy metals in soil: the example of Yushu City, Qinghai Province

Performance and Mechanism of Tailings Biochar Composites for Synergistic Phytoremediation of Soil Heavy Metal Cd

Performance and Mechanism of Tailings Biochar Composites for Synergistic Phytoremediation of Soil Heavy Metal Cd

Detection of heavy metals in soil using Au@SiO2 nanoparticles and surface microstructure combined with laser-induced breakdown spectroscopy.

Detection of heavy metals in soil using Au@SiO2 nanoparticles and surface microstructure combined with laser-induced breakdown spectroscopy.

Uncovering soil heavy metal pollution hotspots and influencing mechanisms through machine learning and spatial analysis.

Uncovering soil heavy metal pollution hotspots and influencing mechanisms through machine learning and spatial analysis.

Health of plateau soil environment: Corresponding relationship of heavy metals in different land use/cover types (LULCC).

Health of plateau soil environment: Corresponding relationship of heavy metals in different land use/cover types (LULCC).

Mechanisms of BpTT2 overexpression in enhancing cadmium tolerence of Broussonetia papyrifera.

Mechanisms of BpTT2 overexpression in enhancing cadmium tolerence of Broussonetia papyrifera.

Microbial Response and the Crucial Function of Predominant Phyla in Sedum alfredii-Mediated Remediation of High Concentration of Multiple Heavy Metal Soils

Microbial Response and the Crucial Function of Predominant Phyla in Sedum alfredii-Mediated Remediation of High Concentration of Multiple Heavy Metal Soils

Analysis on the potential of Pennisetum hydridum for phytoremediation of Cd-polluted soil fertilized by worm castings.

Soil heavy metal pollution including Cd, is the main factor that causes the decline of ecological environment quality, the excessive content in crops and the harm to human health. Phytoremediation is one of the important ways to control heavy metals, which has both ecological and economic benefits. However, most plant species have limited remediation ability and cannot achieve good heavy metal removal effect. In contrast, P. hydridum, easy to cultivate, has large biomass and short growth cycle, shows strong restoration ability in the treatment of heavy metal polluted soil. In order to explore its phytoremediation in Cd-polluted soils under appropriate agronomic measures, this experiment adopts the field random block experiment design to study the control effect and application safety of the application of organic fertilizers (warm castings and biogas slurry) to plant it in the Cd-polluted farmland. The results showed the Cd in the soil after P. hydridum harvesting was 0.53-0.56 mg/kg, and the partial Cd in the shoot was 0.21-0.28 mg/kg (fresh weight), and the enrichment coefficients were all greater than 1, and the extraction amount and efficiency of Cd were 7.17-9.43 mg/m2 and 5.71%-7.01%, respectively. All those data express a decrease in Cd under various treatment conditions, indicating that, P. hydridum can grow under high concentration and it has a certain enrichment effect on Cd, especially in the application of organic fertilizers, which could not only improve the growth performance of the plant, but also improve the soil, much better than that of other Cd hyper-accumulators. Moreover, the positive correlation between the biomass allocation rate and Cd in the soil reflects that the biomass allocation of the plant behaved in different ways with the increase of Cd oil. It is also feasible in terms of application safety due to a long and gradual process to enrich Cd in soil. This study made a proof that it would be a green and environmentally friendly treatment method by making good use of its high biomass to adsorb and remove heavy metals from soil, which would have a good application prospect and development value.