Toxic Elements In Soils Research Articles

An integrated approach to the bioavailability, ecological, and health risk assessment of potentially toxic elements in soils within a barite mining area, SE Nigeria.

Monitoring and assessment of soil quality are important in mining areas. In this study, indexical, spatiotemporal, and chemometric models were developed to monitor and assess the pollution level and health risk of potentially toxic elements (PTEs) within the Iyamitet-Okurumutet mine province, SE Nigeria. Surface soils were sampled within the mine area and analyzed for pH, cation exchange capacity, organic matter, and PTEs (Pb, Zn, Cd, Mn, Fe, Ba) following standard techniques. It was revealed that the soils are slightly acidic and the enrichment of PTEs except for Cd (4.08mg/kg-1) was within recommended standards. Contamination factor, enrichment factor, and pollution index suggest that the soils are moderately polluted. Geospatial maps and ecological risk indices revealed that higher ecological risk imprints seem to increase towards the south-eastern parts of the area. Chemometric analysis revealed that PTE enrichment in the soil is majorly influenced by anthropogenic activities. Further, bioavailability/bioaccessibility risk assessment index (BRAI) and health risk assessment models were developed to quantify the bioavailable/human bioaccessible portion of elements in soils and the associated health risks. The BRAI ranged from high (3 ≥ 5) to very high (> 5) risk of human bioaccessibility; hence, greater amount of PTEs will be bioaccessible for absorption into the human gastrointestinal system than they would for plants uptake. The hazard index and lifetime cancer risk (LCR) revealed that most of the samples present high chronic cancer risks from dermal contact and ingestion for children and adults. The LCR values ranged between 1.0E-6 and 1.0E - 04, with the children population showing greater vulnerability to cancer risks.

Long-term transformation and redistribution of continually added mobile heavy metals and evaluation of their environmental risk: Case study of Khlédia soils (North Tunisia)

The fractional redistribution index of the element i (Utf), whole hole soil redistribution (Uts) and reduced partitioning (binding intensity) (IR) indexes were proposed to quantify the metal transformation and redistribution processes in amended soils with fix quantity of salt metal solutions and incubated for long period. By definition, the initial soil is at equilibrium state the “equilibrium’ parameters (Uts and IR) are equal 1. First, Uts and IR of added heavy metals were high. With time incubation, the Uts and IR must converge towards 1. However, the mobile heavy metal forms could continuously added to agricultural (active) soils. As nay equation was suggested to follow the evolution of the heavy metals transformation and distribution in active soil, the objective of this work is to test if the applied equilibrium parameters in amended soil are useful in this different context. The results showed that (i) the evolution of the equilibrium parameter are sensitive to soil redox, pH, salinity and dissolved organic matter (DOM) concentrations variations, (ii) the continuous toxic metals quantities loading highly increased the Uts and the relative bending intensity (IR) indexes that couldn't never return to quasi-equilibrium state of control soil, and (iii) to predict the environmental risks of added toxic trace elements, the IR is a valid assessor. Therefore, after adopting some new terms definition, the equilibrium parameter could be designed to assess the long-term transformation and redistribution of the continuous input of toxic elements in soil and sediment.

Appraisal of vulnerable zones of non-carcinogenic and carcinogenic causing health risks associated with exposure of potentially toxic elements in soils of India: a meta-analysis

Contamination of soil potentially toxic elements (PTEs) has observed in many parts of the world, specifically developing countries such as India. In this study, we only obtained the available data in the literature from 2001 to 2020 on soil PTEs in India. To evaluate the soil contamination, geo-accumulation index and contamination factor (CF) were implemented, along with the health risk assessment was also applied which was proposed by the US Environmental Protection Agency. The mean values obtained for soils of India are Cr (412.28 mg/kg), Cu (159.78 mg/kg), Zn (437.44), Pb (77.25 mg/kg) and As (38.61 mg/kg). The geo-accumulation index and CF showed that Cu, Zn, Ni and As are the main contaminants. The results of health risk show that children are susceptible to both non-carcinogenic and carcinogenic risks of the studied PTEs compared to adults.

Pollution characteristics and health risk assessment of potentially toxic elements in soils around China's gold mines: a meta-analysis.

Since toxic element pollution is widespread in soils near gold mines due to increasing mining activities, the adverse effects of potentially toxic elements (PTEs) in the soils on ecological systems and human health cannot be ignored. However, assessments of PTE pollution in soils and their ecological-health risks on a national scale are still limited. Here, the concentrations of eight PTEs in soils near gold mines throughout China were obtained from published articles. Based on these data, the pollution levels and ecological-health risks of the eight PTEs in soils were comprehensively estimated. The results showed that the average contents of As, Cr, Cd, Pb, Hg, Cu, Ni, and Zn were 81.62, 79.82, 1.04, 206.03, 2.05, 40.82, 71.82, and 130.42mgkg-1, respectively, which exceeded the corresponding background values for soils. Most of the examined soils were heavily polluted by Hg and Cd, and higher pollution levels were found in the Henan and Shaanxi Provinces than in other regions. The average potential ecological risk value of all PTEs was 2534.71, indicating the presence of very high risks. Contribution of Hg to the potential ecological risk was more than 80%. For adults, all hazard index (HI) values of noncarcinogenic risks were below the safe level of 1.00. For children, none of the HI values exceeded the safe level, with the exception of As (HI = 1.81); nevertheless, four PTEs (As, Cr, Cu, and Ni) presented unacceptable carcinogenic risks. This study provides scientific basis for controlling PTE contamination and reducing the health risks in soils near gold mines worldwide.

Predictive modeling of contents of potentially toxic elements using morphometric data, proximal sensing, and chemical and physical properties of soils under mining influence

Several anthropic activities, especially mining, have contributed to the exacerbation of contents of potentially toxic elements in soils around the world. Mines can release a large amount of direct sources of contaminants into the environment, and even after the mines are no longer being exploited, the environmental liabilities generated may continue to provide contamination risks. Potentially toxic elements (PTEs), when present in the environment, can enter the food chain, promoting serious risks to human health and the ecosystem. Several methods have been used to determine the contents of PTEs in soils, but most are laborious, costly and generate waste. In this study, we use a methodological framework to optimize the prediction of levels of PTEs in soils.We used a total set of 120 soil samples, collected at a depth of 0–10 cm. The covariate database is composed of variables measured by proximal sensors, physical and chemical soil characteristics, and morphometric data derived from a DEM with a spatial resolution of 30 m. Five machine learning algorithms were tested: Random Forests, Cubist, Linear Model, Support Vector Machine and K Nearest Neighbor. In general, the Cubist algorithm produced better results in predicting the contents of Pb, Zn, Ba and Fe compared to the other tested models. For the Al contents, the Support Vector Machine produced the best prediction. For the Cr contents, all models showed low predictive power. The most important covariates in predicting the contents of PTEs varied according to the studied element. However, x-ray fluorescence measurements, textural and morphometric variables stood out for all elements. The methodology structure reported in this study represents an alternative for fast, low-cost prediction of PTEs in soils, in addition to being efficient and economical for monitoring potentially contaminated areas and obtaining quality reference values for soils.

Identification of Sources and Their Potential Health Risk of Potential Toxic Elements in Soils from a Mercury-Thallium Polymetallic Mining Area in Southwest China: Insight from Mercury Isotopes and Pmf Model

Identification of Sources and Their Potential Health Risk of Potential Toxic Elements in Soils from a Mercury-Thallium Polymetallic Mining Area in Southwest China: Insight from Mercury Isotopes and Pmf Model

Impact of Sewage Water on Vegetable Crops and Soils of Bihar

The study of present investigations revealed there is an accumulation of micronutrients and heavy metals in soils with maximum accumulation at the point of discharge. Continuous disposal of sewage-sludge, containing domestic and industrial effluents on agricultural land is a major source of plant nutrients, but it also contains a sufficient amount of non-essential and heavy metals causing soil pollution. Transfer of metals from added sewage sludge to the soils and subsequently uptake by the plants that enter the feed and food-chain which pose hazardous for human health and animals. Moreover, it is pointed out that continued monitoring or treatment of sewage water before disposal into the land or integrated water management are some of the suitable measures for effective utilization of poor quality water in sustainable agricultural production. The concentration of heavy metals like Ni, Cr, Cd and Pb in sewage sludge treated soils at nearby and distant sites from discharge point at Patna bye-pass were investigated. The study revealed that the sites nearest to discharge point contained appreciably higher concentration of these metal cations in comparison to the sites away from the discharge point of the sewage water. Plants growing on such soils accumulate excesses amount of micronutrients and heavy metals in their tissues which may enter in the system of animal and human being. Accumulation of trace metal cations in different plant species differed widely which varied from crop to crop and place to place. The relative accumulation of these metals in different plant species was noticed that leafy vegetables, viz. poi and red spinach (Amaranthus) accumulated most of trace metal cations to the greater extent in comparison to other crops. However, toxic concentration of these trace metal cations in plants and soils should be the matter of concern and indicate the need for continuous monitoring or treatment of sewage water before it is laid down into the field. Though the study during the investigations confirm that sewage water (domestic & urban origin) can certainly and effectively increase water resource for irrigation but there is need for regular monitoring of the concentrations of trace metal cations and potentially toxic elements in soils as well as in plants.

Leaching Experiments and Risk Assessment to Explore the Migration and Risk of Potentially Toxic Elements in Soil from Black Shale

Leaching Experiments and Risk Assessment to Explore the Migration and Risk of Potentially Toxic Elements in Soil from Black Shale

Near-Infrared Spectroscopy for Prediction of Potentially Toxic Elements in Soil and Sediments from a Semiarid and Coastal Humid Tropical Transitional River Basin

Near-Infrared Spectroscopy for Prediction of Potentially Toxic Elements in Soil and Sediments from a Semiarid and Coastal Humid Tropical Transitional River Basin

Contamination, Sources and Health Risks of Toxic Elements in Soils of Karstic Urban Parks Based on Monte Carlo Simulation Combined with a Receptor Model

Contamination, Sources and Health Risks of Toxic Elements in Soils of Karstic Urban Parks Based on Monte Carlo Simulation Combined with a Receptor Model

Distribution of some potentially toxic elements in the soils of the Jharia Coalfield: A probabilistic approach for source identification and risk assessment

AbstractPotentially toxic elements (PTEs) in coal mining soil degrade soil quality and adversely affect people's health. The increasing mining activities in the Jharia Coalfield (JCF) may increase the concentration of PTEs in soils. Therefore, it is vital to have an in‐depth analysis of land degradation caused by them, but there is a lack of accurate and efficient methods to estimate land degradation and health risk analysis in JCF. Therefore, finite mixture distribution model (FMDM), positive matrix factorization (PMF), and Monte Carlo simulation were applied to Jharia's PTEs dataset. The FMDM was employed to distinguish the background concentration and the contamination due to anthropogenic activity. In addition, the contribution of the source was determined through PMF. The FMDM suggested two possible sources of PTEs, while the PMF defines the influence of PTEs more broadly and identifies three sources of PTEs in soil. The results showed that PTEs contribution by a natural source, coal mining, and atmospheric deposition accounted for 45.72%, 27.34%, and 26.94%, respectively. Based on health risk results, this region does not pose a noncarcinogenic risk, but it does pose a carcinogenic risk, especially to infants. JCF comprises a relatively low concentration of PTEs as compared with other possible values for India. Probabilistic health risk assessment studies are scarce for Indian soils, especially in mining areas. In combination, these approaches will provide deeper insights and help identify potential solutions for PTEs contamination in these areas.

Biosurfactant-assisted phytoremediation of potentially toxic elements in soil: Green technology for meeting the United Nations Sustainable Development Goals

Biosurfactants are biomolecules produced by microorganisms, low in toxicity, biodegradable, and relatively easy to synthesize using renewable waste substrates. Biosurfactants are of great importance with a wide and versatile range of applications, including the bioremediation of contaminated sites. Plants may accumulate soil potentially toxic elements (PTEs), and the accumulation efficacy may be further enhanced by the biosurfactants produced by rhizospheric microorganisms. Occasionally, the growth of bacteria slows down in adverse conditions, such as highly contaminated soils with PTEs. In this context, the plant's phytoextraction capacity could be improved by the addition of metal-tolerant bacteria that produce biosurfactants. Several sources, categories, and bioavailability of PTEs in soil are reported in this article, with the focus on the cost-effective and sustainable soil remediation technologies, where biosurfactants are used as a remediation method. How rhizobacterial biosurfactants can improve PTE recovery capabilities of plants is discussed, and the molecular mechanisms in bacterial genomes that support the production of important biosurfactants are listed. The status and cost of commercial biosurfactant production in the international market are also presented.

Human health risk assessment of toxic elements in soils and crops around Xiaoqinling gold-mining area, Northwestern China

The threat to the quality and safety of agricultural products from toxic elemental pollution is a critical contemporary problem. Extensive mining and lax management in the Xiaoqinling gold-mining area from 1986 to 2000 have increased the toxic element concentrations in soils, groundwater, and crops around the mines. Long-term excessive intake of Hg, Pb, Cd, Cr, Cu, and Zn can cause serious life-threatening human diseases, such as hydromelalgia, lead poisoning, Itai Itai disease, chronic rhinopathy, and acute hemolysis. Influenced by local environmental conditions, toxic elements in soils and crops enter the food chain and endanger human health. To determine the health risks from toxic elements introduced by mineral exploitation in Xiaoqinling, soil, wheat, and corn samples were analyzed for Hg, Pb, Cd, Cr, As, Cu, and Zn content. The contamination risks of toxic elements in soils were assessed using the single pollution index and risk assessment code method. The human health risks from toxic elements through wheat and corn consumption were evaluated using transfer factor (TF) and hazard quotient (HQ). The results indicated severe Hg, Pb, Cd, Cu, and Zn accumulation in the mining-affected soils. The TF revealed a relatively easier transformation of Cd, Zn, and Cu from soil to crops, and the HQ showed a high risk of Pb intake from wheat and corn.

A contribution to the mineralogy of Sicily, Italy – Kintoreite from the Tripi mine, Peloritani Mountains: occurrence and crystal structure

AbstractA new occurrence of kintoreite, ideally PbFe3(PO4)(PO3OH)(OH)6, is described from the Tripi mine, Alì, Peloritani Mountains, northeastern Sicily, Italy. Kintoreite occurs as yellow equant crystals, up to 0.05 mm in size, on quartz, associated with another alunite-supergroup mineral currently under study. The studied grains of kintoreite are chemically zoned, showing the occurrence of two distinct domains. Electron microprobe analyses gave (in wt.%): SO3 5.47(27), P2O5 17.55(14), Al2O3 7.81(35), Fe2O3 23.81(44), PbO 35.11(41), H2Ocalc 9.93, total 99.68 (darker domains) and SO3 6.03(5), P2O5 16.66(23), Al2O3 4.22(2), Fe2O3 27.31(6), PbO 33.78(22), H2Ocalc 10.25, total 98.25 (brighter domains). On the basis of 14 O atoms per formula unit (apfu) and (P+S) = 2 apfu, the darker and brighter domains have chemical formula Pb1.00(Fe3+1.89Al0.97)Σ2.86[P1.57S0.43O7.43(OH)0.57][(OH)5.58(H2O)0.42]Σ6.00 and Pb0.98(Fe3+2.21Al0.53)Σ2.74[P1.51S0.49O7.49(OH)0.51][(OH)5.18(H2O)0.82]Σ6.00, respectively. Single-crystal X-ray diffraction was performed on a grain extracted from the same sample. Unit-cell parameters are a = 7.2191(10), c = 16.834(3) Å, V = 759.8(3) Å3 and Z = 3; space group R$\bar{3}$m. The crystal structure was refined on the basis of 226 unique reflections with Fo > 4σ(Fo) and 31 least-square parameters to R1 = 0.0415. Kintoreite is isotypic with other alunite-supergroup minerals. Micro-Raman spectroscopy suggests the possible occurrence of H2O groups, supporting the possible protonation of (OH) groups as a charge-balance mechanism in this mineral. Kintoreite may play an environmental role in the Alì area, where previous authors detected high concentrations of potentially toxic elements in soils.

Source tracing of potentially toxic elements in soils around a typical coking plant in an industrial area in northern China

Coking plants are a substantial source of potentially toxic elements (PTEs) in soil. In this study, we examined the concentration of PTEs, the soil physicochemical properties, and the Pb isotopes in the soil inside and around a coking plant in an industrial city in northern China. We analyzed the spatial distribution of PTEs and the pollution risk areas by Igeo index, the enrichment factor (EF), and the Nemerow index, and we quantitatively identified the contribution of PTE pollution sources in the soil on a small- and medium-scale (plant and work section). Our results indicated that the Hg concentration inside the plant and the Cd concentration in the agricultural land around the plant were both relatively high. A comprehensive analysis of the soil in the study area was performed using the positive matrix factorization model and Pb isotope (206/207Pb, 208/206Pb) tracing method, based on the MixSIAR model, this analysis indicated that burning coal was the main source of Pb both inside (46.8%) and outside (26.3%) the coking plant. The pollution emission sources with significant influence on the soil outside the coking plant were diesel vehicles (12.5%), gas tanks (12.4%), and coke ovens (11.5%), while the sources inside the plant were quenching sections (11.1%), atmospheric deposition (11.0%), coke oven sections (9.6%), and diesel vehicles (6.1%). The results of PTE pollution risk zoning and Pb isotope tracing indicated that pollution is more serious in the western part of the plant, which is the area where coking and gas production takes place, and the most serious pollution outside the plant is mainly distributed to the southeast. This study provides theoretical and practical data indicating the contribution of industrial enterprises to soil pollution, and will help identify pollution responsibility and the management of pollution sources.

Pollution Characteristics, Spatial Patterns, and Sources of Toxic Elements in Soils from a Typical Industrial City of Eastern China

Soil pollution due to toxic elements (TEs) has been a core environmental concern globally, particularly in areas with developed industries. In this study, we sampled 300 surface (0–0.2 m) soil samples from Yuyao City in eastern China. Initially, the geo-accumulation index, potential ecological risk index, single pollution index, and Nemerow composite pollution index were used to evaluate the soil contamination status in Yuyao City. Ordinary kriging was then deployed to map the distribution of the soil TEs. Subsequently, indicator kriging was utilized to identify regions with high risk of TE pollution. Finally, the positive matrix factorization model was used to apportion the sources of the different TEs. Our results indicated that the mean content of different TEs kept the order: Zn > Cr > Pb > Cu > Ni > As > Hg ≈ Cd. Soil pollution was mainly caused by Cd and Hg in the soil of Yuyao City, while the content of other TEs was maintained at a safe level. Regions with high TE content and high pollution risk of TEs are mainly located in the central part of Yuyao City. Four sources of soil TEs were apportioned in Yuyao City. The Pb, Hg, and Zn contents in soil were mainly derived from traffic activities, coal combustion, and smelting. Meanwhile, Cu was mainly sourced from industrial emissions and atmospheric deposition, Cr and Ni mainly originated from soil parental materials, and Cd and As were produced by industrial and agricultural activities. Our study provides important implications for improving the soil environment and contributes to the development of efficient strategies for TE pollution control and remediation.

A holistic methodology to study geochemical and geomorphological control of the distribution of potentially toxic elements in soil

Control of Potentially Toxic Elements (PTEs) in soil-polluted areas is needed to address the potential risk that pollution poses to public health and the environment. This study describes an innovative holistic methodology to assess the distribution of PTEs. It is based on the application of multi-variate statistical and geostatistical algorithms, soil pollution indices and geochemical & geomorphological/climate variables (element concentration, watercourses, winds, slope, orientation and visibility). The methodology proposed is exemplified through a comprehensive soil sampling in an area surrounding a former As-Hg mine that presents several sources of pollutants (abandoned mining spoil heaps, metallurgical waste, old chimneys, etc.). Factor analysis identified four main pollutants of concern: Hg, As, Pb and Sb. The mobility of the most abundant PTEs, especially As, and, to a minor extent, Hg, showed a clear influence of climatic/geomorphological variables. Moreover, the pollution indices confirmed that although the soils in the areas around the spoil heaps contain higher concentrations of the pollutants, the influence of the chimneys is present in the whole study area and depends on factors such as orientation and visibility. In contrast, the fingerprint of the spoil heaps showed a PTE distribution more associated with the slope factor and the presence of watercourses eroding the heaps. All things considered, the methodology proposed revealed PTE sources and distribution in a highly complex site and may therefore find application in similar scenarios of contamination.

Do New-Generation Recycled Phosphorus Fertilizers Increase the Content of Potentially Toxic Elements in Soil and Plants?

Phosphorus (P)-rich secondary raw materials can provide a valuable base for modern mineral fertilizers, provided that the new formulations do not load the soil–plant system with potentially toxic elements. Fertilizers from sewage sludge ash (SSA) and/or animal bones, activated by phosphorus-solubilizing bacteria (Bacillus megaterium or Acidithiobacillus ferrooxidans), were tested in field experiments in north-eastern Poland. The reference provided treatments with superphosphate and treatment without phosphorus fertilization. In one experiment, all P-fertilizers were applied at a P dose of 21 kg·ha−1, and in the other three experiments, three P doses were adopted: 17.6, 26.4, and 35.2 kg·ha−1. The effect of recycled fertilizers on the content of arsenic (As), chromium (Cr), nickel (Ni), copper (Cu), and zinc (Zn) in the soil, in wheat grain and straw (test plant), weeds, and post-harvest residues was investigated. The application of recycled fertilizers in P amounts up to 35.2 kg·ha−1 did not change the As, Cr, Ni, Cu, or Zn contents in the soil and plant biomass. The contents of these elements in soil were below the permissible levels for arable land in Poland. Their concentrations in wheat grain and straw did not exceed the permissible or suggested limits for plant material to be used for food and feed, while in the weed and post-harvest residue biomass, they usually fell within the biological plant variability ranges.

Chemical Fractionation, Environmental, and Human Health Risk Assessment of Potentially Toxic Elements in Soil of Industrialised Urban Areas in Serbia.

The primary focus of this research was the chemical fractionation of potentially toxic elements (PTEs) and their presence in several industrialised cities in Serbia. Furthermore, their origin, contamination levels, and environmental and human health risks were assessed. The results indicated that the examined soils were characterised by slightly higher Cu, Ni, Pb, and Zn levels than those set by European and national regulations. These elevated Cu, Pb, and Zn concentrations were caused by intensive traffic and proximity to industry, whereas the higher Ni levels were a result of the specific geological substrate of the soil in the study area. The environmental risk was found to be low and there was no enrichment/contamination of the soil with these elements, except in the case of Pb, for which moderate to significant enrichment was found. Lead also poses a potential non-carcinogenic risk to children through ingestion and requires special attention due to the fact that a significant proportion of this element was present in the tested soil samples in a potentially available form. Analysis of the health risks showed that children are more at risk than adults from contaminants and that ingestion is the riskiest exposure route. The carcinogenic risk was within the acceptable limits.

Using Fractionation Profile of Potentially Toxic Elements in Soils to Investigate Their Accumulation in Tilia sp. Leaves in Urban Areas with Different Pollution Levels

Optimal uptake of micronutrients (B, Cu, Fe, Mn, and Zn) and managing the potentially toxic elements (PTEs) (Co, Cr, Ni, Pb, and Sr) in the ranges not detrimental to plant function may be linked to improving plants’ healthy growth and the ability to provide ecosystem services. We investigated concentrations, mobility, and potential availability of potentially toxic elements (PTEs) in soil samples from polluted and non-polluted municipal parks in Reading (UK) and Belgrade (Serbia) and their impact on elemental concentrations in Tilia leaves. We aimed to identify common limiting factors potentially affecting the growth/healthy function of this widely-used tree species. Levels of all elements in soil were below limits established by the directive of European Communities, except for Ni at Belgrade sites. Content of Co, Cr, Cu, Fe, Ni, Pb, and Zn in soluble fraction at all locations was <10%, indicating low mobility; B showed moderate mobility (11.1–20.7%), Mn (6.5–55.6%), and Sr—high (44–76.3%). Principal Component Analysis of Tilia leaf tissues showed a different capacity for uptake/accumulation of PTEs in different locations. Findings indicate the complexity of local edaphic influences on plants’ elemental uptake and the risk of those leading to deficiency of important micronutrients, which may impede trees’ function and thus the ability to optimally provide ecosystem services.