Sources Of Potentially Toxic Elements Research Articles

Contamination levels of and potential risks from metal(loid)s in soil-crop systems in high geological background areas

Soil metal(loid)s in high geological background areas occur mainly in the residual form with low bioavailability, and whether these potentially toxic elements (PTEs) in agricultural soils are harmful to human health is of considerable public concern. A paired survey using both soil and crop samples was conducted using 437 contaminated sites in east Yunnan province, southwest China. The concentration, distribution, and source of PTEs (arsenic (As), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), and chromium (Cr)) in agricultural soils, and the contamination levels of and potential health risks from PTEs from different pollution sources were evaluated. Soil Pb, Cu, Zn, Cd, Cr, and As concentrations were higher than the Chinese screening values (GB 15618-2018) of 10.98, 36.16, 24.71, 86.96, 14.19, and 6.64 %, respectively, and Cd greatly exceeded the screening values. Spatial distribution maps indicate that areas with high concentrations of Pb, Cu, Cd, and As were located mainly in mining areas. However, the Zn and Cr concentrations were relatively homogeneous and more dependent on natural processes. The source identification of PTEs shows that Zn and Cr in soils were controlled mainly by the geological background, Pb and As were closely related to anthropogenic activities, and Cu and Cd were related to both sources. Different pollution sources affected crop PTE contents, with average concentrations of Zn, Cd, Cr, and As in high geological background areas significantly lower than in anthropogenic activity areas (p < 0.001), while Cu and As did not differ significantly. Although soil PTEs in high geological background areas represent a relatively high potential risk, they had little impact on crop quality. The hazard indices of different crop products for adults and children followed the sequence: cereals > leafy vegetables > rootstalk vegetables > fruit vegetables. Rootstalk and fruit vegetables are recommended to be grown in the study areas because they are safe for human consumption.

Geographic distribution, source analysis, and ecological risk assessment of PTEs in the topsoil of different land uses around the antimony tailings tank: A case study of Longwangchi tailings pond, Hunan, China

Few studies have addressed the contamination of surface soils around antimony tailings ponds, and studying the contamination levels and sources of potentially toxic elements (PTEs) in soils around antimony tailings ponds and assessing the associated environmental risks are key steps in conducting environmental protection. Therefore, this study is the first to investigate the current status, spatial distribution, potential sources and ecological risks of Pb, Sb, Cr, Zn, Cd, As and Cu contamination in surface soils in woodlands, grasslands, farmlands and construction areas around the Longwangchi antimony tailings pond in Hunan, China. According to the analytic results of soil samples, the order of PTEs in terms of average concentration is: Sb > Zn > Cu > Pb > As > Cr > Cd. The cumulative index of land was applied to define Sb and Cd as extremely heavy pollution, and PLI divides the overall pollution level of soil into serious pollution levels. The ecological risk index was used to evaluate the risk characteristics of PTEs. The results showed that the ecological risk of Sb was particularly prominent, and 95% of the study area had reached a very high risk level. A quantitative comparison of ecological risk levels between different land uses revealed that there was a clear dividing line between regions, with built-up areas contributing the most to higher ecological risk at 8.89%, followed by 1.72% for grassland, 1.15% for agricultural land, and 0.57% for woodland. The visualization results of spatial distribution of PTEs exhibited that severe pollution occurred in the middle, north and southeast of the study area, and these distribution characteristics are mainly dictated by the polluted runoffs from tailings ponds and human activities. Principal component analysis (PCA) and positive matrix decomposition (PMF) were employed to identify the exact pollution sources, and the closer the determination coefficient (R2) of PMF was to 1, the finer the pollution sources analyzed. A total of six potential sources of PTEs were analyzed by PMF: 36% of tailings pond contamination and mining operations, 8% atmospheric deposition, 19% traffic emissions, 9% combustion emissions, 11% natural sources, and 17% inputs related to agricultural production. This study is a complement to the study of environmental pollution around antimony tailing ponds, providing evaluation criteria for the pollution identification indicators of antimony tailing ponds.

Environmental risk assessment of potentially toxic elements in Doce River watershed after mining sludge dam breakdown in Mariana, MG, Brazil.

Faced with a potential risk of a colossal amount of sludge released into the Doce River basin in the most shocking Brazilian mining disaster, we proposed to assess the environmental risk from a new perspective: Understanding the mobilization of potentially toxic elements (PTE) with the geochemical fractions. Soil and sediment samples were taken in nine sites throughout the basin and characterized. The environmental risk was assessed from the PTE sequential extraction in three fractions: soluble, reducible, and oxidizable, in addition to the pseudo-total concentration. The potential mobile fraction (PMF) showed a considerable PTE mobilization from the soil and sediment samples. Principal component statistical analysis indicated the sludge as the single source of PTE. The risk assessment depended on the fractional distribution and the PTE enrichment degree in the affected samples. The fractional distribution contributed mainly to Mn, Sb, and Pb mobility, with PMF of 96%, 81%, and 100%, respectively. The mobilization of Cd, Co, Ag, Ni, Pb, Zn, and Cu was predominantly related to the degree of enrichment. The risk assessment from the geochemical fractions pointed to the magnitude of the disaster and the dispersion of PTE with severe effects on the affected populations. Therefore, more strongly enforced regulations in the basin are needed, in addition to the urgent use of more secure containment dams. It is also essential to emphasize the transferability of the design of this study to other environmental units in mining disaster conditions.

Assessment of sources, environmental, ecological, and health risks of potentially toxic elements in urban dust of Moscow megacity, Russia

Potentially toxic elements (PTEs) in urban dust of Moscow megacity and related risks have been studied. 78 samples were collected in the Moscow downtown in sites with different anthropogenic load, namely, major highways, residential area, and recreation zones. The concentrations of PTEs in urban dust were determined by ICP-MS and ICP-AES. Then, environmental, ecological and health risks of PTEs in urban dust were assessed. In addition, potential sources of PTEs in dust were identified. It is shown that Moscow dust is mainly contaminated by Sb, Zn, Pb, Cd, Cu, Sn, and Mo, which according to the data of principal component and correlation analyses can be attributed to anthropogenic sources (non-exhaust vehicle emissions). Potential ecological risk factor demonstrates that Cu, Mo, and Cd have moderate potential ecological risks in 13% of studied area, while Sb has this risk in 62% of area. Potential ecological risk indices indicate that 41% of studied territory is of moderate ecological risk. Concerning the human risks through ingestion, dermal contact, and inhalation pathways, PTEs in Moscow dust have no significant non-carcinogenic risks for adults. However, the value of total hazard index for children is 1.8 showing that non-carcinogenic risks may occur. Moreover, possible carcinogenic risks caused by Cr are evaluated. The finding of the present study can be used for ecological management in the megacity to reduce both ecological and human risks. A special attention should be given to periods of hot and dry weather and to traffic-related emissions.

Phytoremediation of Potentially Toxic Elements: Role, Status and Concerns.

Environmental contamination with a myriad of potentially toxic elements (PTEs) is triggered by various natural and anthropogenic activities. However, the industrial revolution has increased the intensity of these hazardous elements and their concentration in the environment, which, in turn, could provoke potential ecological risks. Additionally, most PTEs pose a considerable nuisance to human beings and affect soil, aquatic organisms, and even nematodes and microbes. This comprehensive review aims to: (i) introduce potentially toxic elements; (ii) overview the major sources of PTEs in the major environmental compartments; (iii) briefly highlight the major impacts of PTEs on humans, plants, aquatic life, and the health of soil; (iv) appraise the major methods for tackling PTE-caused pollution; (v) discuss the concept and applications of the major eco-technological/green approaches (comprising phytoextraction, rhizofiltration, phytostabilization, phytovolatilization, and phytorestoration); (vi) highlight the role of microbes in phytoremediation under PTE stress; and (vii) enlighten the major role of genetic engineering in advancing the phytoremediation of varied PTEs. Overall, appropriate strategies must be developed in order to stop gene flow into wild species, and biosafety issues must be properly addressed. Additionally, consistent efforts should be undertaken to tackle the major issues (e.g., risk estimation, understanding, acceptance and feasibility) in order to guarantee the successful implementation of phytoremediation programs, raise awareness of this green technology among laymen, and to strengthen networking among scientists, stakeholders, industrialists, governments and non-government organizations.

Effect of parent material and atmospheric deposition on the potential pollution of urban soils close to mining areas

The aim of this study is to analyse the concentration and determine the sources of potentially toxic elements (PTEs) in urban soils under the influence of mining activities. To this end, topsoil samples were collected in the public parks and green areas in Minas de Riotinto (a town next to one of the largest open pit mines in the world) and Aracena (a nearby town outside the area of influence of the mine). After determining the concentrations of elements of interest Cr, Co, Ni, Cu, Zn, As, and Pb— the values were compared in terms of the soil location and origin (in-situ or ex-situ), and with the background and regulatory levels for the region. The elemental concentrations in the fine fraction of the soils (particles <50 μm) were also measured. The concentrations of some PTEs (Cu, As and Pb), also found in the dust from nearby mines, were higher in the in-situ soils of Minas de Riotinto than in those of Aracena. The concentrations of PTEs in ex-situ soils of both towns were much lower than in in-situ soils, and similar between the two locations, revealing the influence of the parent material as a primary source of PTEs. However, the concentrations of As and Cu in the ex-situ soils of Minas de Riotinto were significantly higher than in those of Aracena, while a significant increase of these elements in the fine fraction was seen for both in-situ and ex-situ soils. These two elements are directly related to mining activity, implying that atmospheric deposition of dust from the mines contributes to the greater concentration of PTEs in the soils of Minas de Riotinto. Because these sources lead to soils with potentially dangerous concentrations of pollutants, they should be further studied in relation to their long-term influence on human health.

Contamination, Source Identification, Ecological and Human Health Risks Assessment of Potentially Toxic-Elements in Soils of Typical Rare-Earth Mining Areas.

The mining and leaching processes of rare-earth mines can include the entry of potentially toxic elements (PTEs) into the environment, causing ecological risks and endangering human health. However, the identification of ecological risks and sources of PTEs in rare-earth mining areas is less comprehensive. Hence, we determine the PTE (Co, Cr, Cu, Mn, Ni, Pb, Zn, V) content in soils around rare-earth mining areas in the south and analyze the ecological health risks, distribution characteristics, and sources of PTEs in the study area using various indices and models. The results showed that the average concentrations of Co, Mn, Ni, Pb and Zn were higher than the soil background values, with a maximum of 1.62 times. The spatial distribution of PTEs was not homogeneous and the hot spots were mostly located near roads and mining areas. The ecological risk index and the non-carcinogenic index showed that the contribution was mainly from Co, Pb, and Cr, which accounted for more than 90%. Correlation analysis and PMF models indicated that eight PTEs were positively correlated, and rare-earth mining operations (concentration of 22.85%) may have caused Pb and Cu enrichment in soils in the area, while other anthropogenic sources of pollution were industrial emissions and agricultural pollution. The results of the study can provide a scientific basis for environmental-pollution assessment and prevention in rare-earth mining cities.

Contamination of useful plant leaves with chromium and other potentially toxic elements and associated health risks in a polluted mining-smelting region of South Africa

• Foliar Al, Co, Cr and Hg concentrations exceeded international permissible levels. • Cr(VI) was detected in unwashed leaves and soils from outcrops and polluted sites. • Among all PTEs, only Cr had a Hazard Quotient value > 1 for unwashed leaves. • Estimated weekly intake of Hg exceeded recommended PTWI. • Carcinogenic risks were high for Cr(VI), total Cr and Ni. Foliar exposure to dust-borne potentially toxic elements (PTEs) is often overlooked in chromium (Cr) mining and industrial regions. A comparative analysis of unwashed (UL) and washed leaves (WL) was conducted to investigate the contribution of dust to Al, As, Cd, Co, Cr (total and hexavalent Cr (Cr(VI)), Cu, Hg, Mn, Mo, Ni, Pb, Sb, V and Zn contents of leafy vegetables and medicinal plants from chromitite outcrops and Cr mining-smelting localities in Sekhukhuneland, South Africa. For leafy vegetables, health risks were estimated for all PTEs except Al and Hg, for which weekly intakes were calculated. Mean total Cr levels in UL and WL exceeded the international permissible levels by up to 22- and 9-fold, respectively, linking foliar Cr contamination to dust deposition and a lesser extent, accumulation in tissue. The most hazardous Cr species, Cr(VI) was detected in soil-plant (UL) systems of outcrops and polluted sites. Unwashed leaves had higher mean concentrations of 71% of the assessed PTEs (except Cd, Co, Hg and Sb) than WL, indicating dust as a source of PTEs. Only Cr had a Hazard Quotient (HQ) > 1 (UL). The HQ of Cr and Co contributed the most to the Hazard Index of UL (1.70) and WL (1.39). Carcinogenic risk was > 1 × 10 ‒4 for Cr(VI) (UL) and > 1 × 10 ‒3 for total Cr (UL > WL) and Ni (WL > UL). Estimated weekly intake of Hg (WL > UL) exceeded Provisional Tolerable Weekly Intake. Lifelong consumption of unwashed and even washed leafy vegetables might be hazardous in the study locality. Regular monitoring of PTE levels in the dust-soil-plant system is necessary for Cr mining-smelting regions.

Evaluation of the 13 May 2018 frontal dust storm in Shiraz: Stable isotopes signature, source apportionment, and concentration of potentially toxic elements

• Shiraz dust storm event mainly originated from the Saudi Arabia Peninsula. • The aerosol composition was affected by Persian Gulf sea salt and soil erosion in Iran and Iraq. • The target PTEs had the highest concentration in the central parts of the city. • These results were based on the mineralogy, δ 18 O and δ 13 C values, PMF and HYSPLIT modeling, and elemental ratios. Frontal dust storms are rare but important weather events in southern Iran affecting visibility and air quality, especially in urban areas. This study investigated the main characteristics of the 13 May 2018 frontal dust storm in Shiraz. The evaluation was based on geostatistical models, and mineralogical, elemental and isotopic data. The mean and median concentrations of major and trace elements followed the order Ca > Al > Fe > Mg > K > Na > Ti > Mn > Zn > V > Cr > Ni > Cu > Pb > Co > Cd, in agreement with the mineralogical composition of dust samples. The spatial distributions of the potentially toxic elements (PTEs) show that the concentrations were higher in the central sectors of city, likely due to the higher population density and traffic volume. Integrated source characterization coupled with positive matrix factorization (PMF) identified that the PTEs sources were geogenic, anthropogenic, and sea salt related. Geochemical isotopic methods, δ 18 O and δ 13 C values along with hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) analysis suggest that the dust storm mainly originated from Saudi Arabia. However, local lithological units and resuspended street dust also played an important role in the elemental distributions. These results also indicate that combining various datasets can be beneficial in characterizing the sources of dust storms and their components in southwestern Iran.

Pollution Characteristics, Source Apportionment, and Health Risk Assessment of Potentially Toxic Elements (PTEs) in Road Dust Samples in Jiayuguan, Hexi Corridor, China.

The sources of potentially toxic elements (PTEs) in road dust are complex and potentially harmful to humans, especially in industrial cities. Jiayuguan is the largest steel-producing city in Northwest China, and this study was the first to conduct a related study on PTEs in road dust in this city, including the pollution characteristics, source apportionment, and health risk assessment of PTEs in road dust. The results showed that the highest concentration of PTEs in the local road dust samples were Mn, Ba, Zn, and Cr. The enrichment factor (EF) of Se was the highest, and it was “Very high enrichment” in areas other than the background area, indicating that the local Se was more affected by human activities. The geoaccumulation index (Igeo) of Se was also the highest, and the pollution level was 5 in all areas except the background area, indicating that the local Se was more polluted and related to coal combustion. The sources of PTEs in local road dust samples mainly included geogenic-industrial sources, coal combustion, traffic sources, and oil combustion. For the non-carcinogenic risk, the hazard index (HI) of each element of children was higher than that of adults, and the sum of the HI of each element was greater than 1, indicating that there was a non-carcinogenic risk under the combined influence of multiple elements, which was especially obvious in industrial areas. For the carcinogenic risk, the cancer risk (CR) of Cr at a certain point in the industrial area exceeded 10−4, which was a carcinogenic risk, and the Cr in this area may be related to the topsoil of the local abandoned chromate plant.

Contamination level, source identification and health risk assessment of potentially toxic elements in drinking water sources of mining and non-mining areas of Khyber Pakhtunkhwa, Pakistan.

Accelerated mining activities have increased water contamination with potentially toxic elements (PTEs) and their associated human health risk in developing countries. The current study investigated the distribution of PTEs, their potential sources and health risk assessment in both ground and surface water sources in mining and non-mining areas of Khyber Pakhtunkhwa, Pakistan. Water samples (n = 150) were taken from selected sites and were analyzed for six PTEs (Ni, Cr, Zn, Cu, Pb and Mn). Among PTEs, Cr showed a high mean concentration (497) μg L-1, followed by Zn (414) μg L-1 in the mining area, while Zn showed the lowest mean value (4.44) μg L-1 in non-mining areas. Elevated concentrations of Ni, Cr and a moderate level of Pb in ground and surface water of Mohmand District exceeded the permissible limits set by WHO. Multivariate statistical analyses showed that the pollution sources of PTEs were mainly from mafic-ultramafic rocks, acid mine drainage, open dumping of mine wastes and mine tailings. The hazard quotient (HQ) was the highest for children relative to that for adults, but not higher than the USEPA limits. The hazard index (HI) for ingestions of all selected PTEs was lower than the threshold value (HIing < 1), except for Mohmand District, which showed a value of HI >1 in mining areas through ingestion. Moreover, the carcinogenic risk (CR) values exceeded the threshold limits for Ni and Cr set by the USEPA (1.0E-04-1.0E-06). In order to protect the drinking water sources of the study areas from further contamination, management techniques and policy for mining operations need to be implemented.

A comprehensive study of potentially toxic element contamination and source quantitative assessment by positive matrix factorization model: risk from the fine road dust of Chehe mining area, China.

Extreme mining activities can risk human life and the environment via potentially toxic elements (PTEs) in road dust, thus making their quantification and assessment unavoidable. For this purpose, we collected 50 fine road dust samples from the Chehe mining area, China, to quantify the level of contamination and ecological and health risks of PTEs comprising As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, and Zn, and their quantitative source apportionment using the positive matrix factorization model (PMF). Results indicated that the average values of Cd, Sb, As, Zn, Pb, and Cu in road dust were 1555.21, 586.78, 429.68, 429.43, 72.88, and 26.61 times higher than their background values. Pollution indices of PTEs revealed a strong level of contamination by Cd, Sb, As, Zn, and Pb, which were extremely polluted in the study area. The average values of the Nemerow integrated risk index (NIRI) and potential ecological risk index (RI) were 104.09 and 86.49 times the highest risk limit, respectively, which are extremely high ecological risks. Based on PMF for quantitative source identification, mining activities and fuel combustion were the main sources of PTEs in road dust contributing 57.25% and 35.95%, respectively. Furthermore, the health risk assessment indicated that Sb, As, Cr, Cd, and Pb in the Chehe road dust could lead to significantly serious carcinogenic and non-carcinogenic risks to both children and adults. The results of this study could be used to opt for strategies to mitigate the ecological and human health risk in the mining area of Hechi, China.

Assessing risk to human health for potentially toxic elements in farmed and wild giant tiger prawn (Paeneas monodon) in the coastal area of Bangladesh

ABSTRACT Giant tiger prawn (Penaeus monodon) is an important marine crustacean widely reared for food all over the world but poses a health risk if it is contaminated by toxic elements. Potentially toxic elements (PTEs), i.e. copper (Cu), chromium (Cr), nickel (Ni), arsenic (As), cadmium (Cd), lead (Pb), manganese (Mn) and zinc (Zn) in wild- and farm-cultured prawns were measured for the first time to assess the levels of PTEs, their sources and health risks. Average concentrations (mg/kg) of Cr, Ni, Cu, As, Cd, Pb, Mn and Zn in farm prawn were 3.13, 3.06, 14.21, 1.28, 0.50, 1.32, 5.89 and 7.68, respectively, and in wild prawn, they were 0.98, 2.43, 8.48, 0.45, 0.19, 0.46, 2.77 and 3.88, respectively. Except Ni and Zn, the concentrations of PTEs in prawn samples were higher than the maximum allowable concentration (MAC), indicating their contamination by PTEs which might pose risks to human health. Multivariate principal component analysis (PCA) revealed that anthropogenic activities including industrial wastes and agricultural chemicals are substantial sources of PTEs in the samples. Estimated daily intake (EDI), target hazard quotient (THQ) and target carcinogenic risk (CR) assessed for potential human health risk implications suggest that the values were slightly higher than the acceptable threshold for both adults and children.

Mineralogical association and geochemistry of potentially toxic elements in urban soils under the influence of mining

Polluted soil is an important source of exposure to potentially toxic elements (PTEs) for humans, especially in urban areas. We studied the fate of PTEs in the total (<2 mm) and fine (<50 µm) fractions of urban soils in playgrounds, passing areas, and vacant lots of the historic mining village of Minas de Riotinto in SW Spain. The mineralogical and chemical observations included analysis by scanning electron microscopy, electron backscatter diffraction, X-ray diffraction, chemical analysis of Al, V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, As, Cd, Ba, Tl, and Pb after acid digestion by Inductively Coupled Plasma-Mass Spectrometry and Sb by X-ray fluorescence.The total and fine fractions of natural and mixed (consisting of natural soils and aggregate pavements) urban soils have significantly higher concentrations of sulfide-associated PTEs (Ni, Cu, Zn, As, Sb, and Pb) and Ba in comparison to the aggregate pavements. Most of the natural and mixed urban soils surpass the regulatory levels set by the regional Government for As and Pb to declare a soil as contaminated. This work highlights the mineralogical source of PTEs in the urban soils. Primary geogenic sulfide minerals are prone to oxidation promoting dissolution of PTEs and acid generation in the future. Additionally, for the first time, we have described arsenian plumbojarosite and beudantite in urban soils which are abundant secondary phases under the circumneutral pH conditions, effectively retaining As and Pb. Inhalable small PTE-rich particles (<10 μm) are present in many soils in playgrounds and garden areas potentially posing health risk to residents upon dusting and resuspension in the air.

Natural and anthropogenic sources of potentially toxic elements to aquatic environment: a systematic literature review.

Potentially toxic elements (PTEs) constitute a class of metals, semimetals, and non-metals that are of concern due to their persistence, toxicity, bioaccumulation, and biomagnification in high concentrations, posing risks to the ecosystem and to human health. A systematic literature review (SLR) was used in this study to identify natural and anthropogenic sources of PTEs for the aquatic environment. The databases consulted were ScienceDirect, Scopus, and Web of Science, in the period 2000-2020, using specific terms and filters. After analyzing the titles, abstracts, and full texts, 79 articles were selected for the SLR, in which 15 sources and 16 PTEs were identified. The main anthropogenic sources identified were mining, agriculture, industries, and domestic effluents, and the main natural sources identified were weathering of rocks and geogenic origin. Some places where environmental remediation studies can be carried out were highlighted such as Guangdong province, in China, presenting values of Cd, Cr, and Cu exceeding the national legislation from drinking water and soil quality, and Ardabil Province, in Iran, presenting values of As, Cr, Cu, Ni, Zn, and Pb exceeding the standard for freshwater sediments of USEPA, among others places. With the results exposed in this work, the government and the competent bodies of each locality will be able to develop strategies and public policies aimed at the main sources and places of contamination, in order to prevent and remedy the pollution of aquatic environments by potentially toxic elements.

Sources Identification, Ecological Risk Assessment, and Controlling Factors of Potentially Toxic Elements in Typical Lead-Zinc Mine Area, Guizhou Province, Southwest China

Carbonatite and basalt are widely distributed in southwest China, and potentially toxic elements (PTEs) are associated with the naturally high background properties. It is important to carry out ecological risk assessments and identify potential sources of PTEs. A total of 3180 soil samples (0-20 cm) were collected in Hezhang county, a typical high background area of PTEs with the parent lithology of carbonatite and basalt. Samples were obtained from 18 large lead-zinc mines, which belong to a multi-ecological risk superimposed area with high ecological risk. The concentration of PTEs (Cd, Cr, As, Hg, Pb, Cu, Zn, and Ni) in the topsoil were analyzed, and statistical analysis (SA), geographic information system (GIS), enrichment factor (EF), potential ecological risk index (RI), and positive matrix factorization (PMF) methods were used to assess the ecological risk and quantify sources of PTEs. The mean values of PTEs concentrations in topsoil were 24.55, 2.25, 176.40, 89.60, 0.19, 64.20, 102.00, and 257.00 mg·kg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively, which were remarkably higher than the average background value (ABV) of soils in Guizhou Province. The average concentrations of Cd, Cr, Cu, Ni, Pb, and Zn exceeded the screening values specified for the soil contamination risk in agricultural land (GB 15618-2018) by 7.50, 1.18, 1.79, 1.07, 1.40, and 1.29 times, respectively. The EF showed that Cd had a large area of moderate pollution; Pb, Zn, and Cu had a small area of slight pollution; the EFs values of Hg, Cr, Ni, and As were near the baseline value (EF≈1), and contaminations were slight or nonexistent. The PMF indicated that there were five sources, namely pyrite mines, lead-zinc mines, natural sources of basalt and carbonatite, and agricultural activities; the risk contribution ratios were 5.25%, 27.37%, 28.94%, 17.91%, and 20.53%, respectively. The most toxic coefficients of Hg and Cd were mainly natural sources, with contribution ratios of 86.3% and 72.7%, respectively. The soil samples in the mining areas expectedly contained high ratios of Zn/Cd and Pb/Cd, which confirmed that PTEs in the soil were mainly derived from the smelting wastes. The contents of metal oxides such as Fe, Mn, and Si were the influencing factors of PTEs enrichment. On the contrary, soil samples exhibited much lower Zn/Cd and Pb/Cd ratios in non-mining areas, indicating that the main origin of these metals in soil was the smelting flue gas dusts and geological background.

Influence of beech and spruce on potentially toxic elements-related health risk of edible mushrooms growing on unpolluted forest soils

Atmospheric deposition-related potentially toxic elements (PTEs) can contaminate mountain forest ecosystems. The influence of tree species is being increasingly recognised as an important factor in the deposition loads in forest soils. However, relevant modelling studies about the forest pollution with PTEs, concerning the tree species composition, are lacking. The aim of this study was to evaluate the effect of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H. Karst.) on soil and mushroom pollution and the associated health risks to define their significance for pollution modelling. Therefore, topsoil samples and samples of eight edible mushroom species were taken from 51 mature beech- and spruce-dominated stands. The results showed that forest composition had an indirect influence on the PTEs contents in the topsoil; it significantly differentiated the relationship between PTEs and soil C as the beech stands showed significantly increasing PTEs content with increasing C content. Despite the absence of soil pollution, above-limit levels of Cd and Zn were found in mushrooms. The total content of PTEs in mushrooms posed a potential health risk to consumers in 82% of the samples. The most Cd-contaminated and potentially the riskiest species for consumption was Xerocomellus pruinatus (Fr. and Hök) Šutara. The results suggest that the source of PTEs for mushrooms is not only the soil but probably also the current wet deposition. The influence of the forest type on the accumulation of PTEs in mushrooms was confirmed mainly due to the strongly divergent behaviour of Zn in beech- vs. spruce-dominated stands. The results point to the need to evaluate mushroom contamination even in the contamination-unburdened forest areas. For future modelling of PTEs pollution in forests, it is necessary to differentiate the tree species composition.

The sources risk assessment combined with APCS/MLR model for potentially toxic elements in farmland of a first-tier city, China.

With the rapid economic development, potentially toxic elements (PTEs) are continuously migrating, transforming, and enriching in farmland through atmospheric deposition and other media, posing threats to food security and human health. At present, there are few quantitative studies on the health risks of PTEs sources in farmland. In this study, absolute principal component score-multiple linear regression (APCS-MLR) receptor model was used to quantify the pollution sources of PTEs in farmland in Suzhou of Yangtze River Delta Economic Zone, China. Combined with geoaccumulation index (Igeo) and health risk assessment model, the source risk of PTEs was further quantified. The results show that Cd has reached the level of unpolluted to moderate polluted (0 < Igeo < 1); the total hazard index (THI) and total carcinogenic risk (TCR) index of PTEs are acceptable for adults, but not for children (THI > 1, TCR > 1 × 10-4). The results of APCS-MLR source apportionment were industrial sources (25.65%), agricultural sources (20.00%), traffic sources (16.81%), and domestic pollution sources (9.71%). The Igeo values of all pollution sources were less than 0, and no ecological risk was caused. The contribution patterns of pollution sources to THI and TCR in adults and children are similar. Industrial pollution sources pose the greatest non-carcinogenic risk to humans, accounting for 47.35% and 47.26% of adults and children, respectively; for carcinogenic risks, domestic pollution sources contribute the most among all identified pollution sources, accounting for 27.71% and 27.73% of adults and children, respectively. In general, this study emphasizes the need to strengthen the supervision of industrial pollution sources and domestic pollution sources in the study area to reduce the health risks to children.

A comprehensive exploration on the health risk quantification assessment of soil potentially toxic elements from different sources around large-scale smelting area.

Non-ferrous metal smelting activities have always been considered as one of the foremost anthropogenic sources of potentially toxic elements (PTEs). The enrichment factor (EF) and pollution load index (PLI) were used to evaluate the pollution level of soil PTEs; positive matrix factorization (PMF), correlation analysis, and geostatistics were utilized to quantify the sources of soil PTEs; and potential ecological risk (PER) and human health risk (HHR) of different sources from farmland, construction land, and natural land were quantifiably determined via combined PTE sources with PER and HHR assessment models. Taking the smelting area of Daye City as an example, the evaluation results of EF and PLI showed that the soil PTE pollution in the study area was serious, especially Cd and Cu. And four sources were quantitatively allocated as agricultural practices (12.14%), traffic emissions (23.07%), natural sources (33.46%), and industrial activities (31.33%). For PER, industrial activities were the largest contributor to PER, accounting for 55.66%, 56.30%, and 55.36% of farmland, construction land, and natural land, respectively, and Cd was the most dangerous element. In terms of HHR, industrial activities were also the cardinal contributors under the three land use types. Children were exposed to serious non-carcinogenic risks under three land use patterns and slight carcinogenic risk in construction land (1.06E - 04). Significantly, the carcinogenic risk of children in farmland (9.06 × 10-5) was very close to the threshold (1 × 10-4), which requires attention. Both non-carcinogenic and carcinogenic risk for adults were all at acceptable levels. The health risks (carcinogenic and non-carcinogenic risks) of children from four different sources were distinctly higher than those of adults. Consequently, strict management and control of industrial activities should be given priority, and the management of agricultural practices should not be ignored.

Integrated approaches to mitigate threats from emerging potentially toxic elements: A way forward for sustainable environmental management

Potentially toxic elements (PTEs) such as toxic metal (loid)s and other emerging hazardous contaminants, exist in the environment and poses a serious threat. A large amount of wastewater containing PTEs such as cadmium, chromium, copper, nickel, arsenic, lead, zinc, etc. Release from industries during production process. Besides these, chemical-based fertilizers used in soils during crop production have become one of the crucial sources of PTEs. Various techniques are being employed for the mitigation of PTEs like chemical precipitation, ion exchange, coagulation, activated carbon, adsorption, membrane filtration, and bioremediation. Among these mitigation strategies, biological processes such as bioremediation, phytoremediation etc. Are extensively used, as they are economic have high-efficiency rate and are eco-friendly. This review intends to provide information on PTEs contamination through various sources; along with the toxicity of metal (loid)s with respect to their patterns of transmission and risks in the changing environment. Various remediation methods for the management of these pollutants along with their techno-economic perspective are also summarized in this review.