Search Results (50)

Metal(loid)s and nonmetals in the soil of urban parks can pose risks to human health. Thus, we aimed to study the soil elemental content, soil types and their pH, contamination factor, geo-accumulation index, pollution load index, total carcinogenic risk, and hazard quotient for children and adults by ingestion, inhalation, and dermal routes contact in ecological parks (EP) in Central-West Brazil. In Lago do Amor EP, high concentrations of Mg and Mn and lower pH values predominate, while in the Águas do Prosa EP, there is a greater influence of Zn. Except for the range of average concentrations of Al, Fe, P, Mg, and Mn in all EP soils, the range of the average concentrations of As, Cd, Co, Pb, Cr, Cu, Mo, Se, and Zn were generally higher than those permissible limits. There is moderate contamination by Mo, Ni, Cd, and mainly Se in Lago do Amor, Anhanduí, and Sóter EPs. The geo-accumulation index revealed that Lago do Amor EP is moderately polluted by Cd. Oral ingestion was evidenced as the main route of possible contamination by heavy metals, especially for children, who presented a carcinogenic risk greater than 10⁻¹ for As, Cr, and Ni. Full article

Soil pollution is a global threat that seriously affects biodiversity in (agro)ecosystems and may compromise water and food quality. Therefore, the ability of tree species (Populus tremula, Salix caprea, and Betula pendula) to accumulate and phytoextract specific toxic heavy metals from soil was investigated. The study was conducted in and near relict mining areas of Freiberg (Germany) and sampling sites selected according to their spatial location relative to potential sources of metal(loid)s. The concentrations of geogenic (P, Fe, Mn, Ca) and pollutant (Pb, Cd, Zn, As) elements in soil and the present trees were measured using ICP-MS. The highest total soil concentrations of As (8978 µg g⁻¹) were found within the Davidschaft mining area, and for soil Pb, both in the Davidschaft vicinity (328 µg g⁻¹) and mining area (302 µg g⁻¹). Unexpectedly, the highest soil Zn (0.64 mg g⁻¹) and Cd (3.5 mg g⁻¹) concentrations were found in Freiberg city Forest. The lowest soil concentrations of pollutants (As, Cd, Pb, and Zn) were recorded for Seifersdorf. Total soil P was highest in Colmnitz, but Ca, Mn, and Fe concentrations were very similar across all sites. The available concentration of all measured toxic elements in the soil generally decreased in the order Davidschaft > Davidschaft vicinity, Colmnitz > Seifersdorf = Freiberg city forest. All studied tree species had higher concentrations of the essential elements in leaves than in branches. Generally, higher values of bioaccumulation coefficients (especially for Cd) were found for Salix caprea compared with Populus tremula and Betula pendula. Full article

The rhizosphere is a crucial interface that connects the soil and the roots of plants, playing a critical role in regulating soil biochemical functions and processes. Biochar, an increasingly common soil amendment, can directly or indirectly affect the redistribution behavior of heavy metal(loid)s. Our study used a rice pot experiment to investigate the redistribution behavior of antimony (Sb) in the rhizosphere–rice system during the four key rice growth stages and analyze the effects of biochar (BC). Biochar increased pH, soil organic matter (SOM), and dissolved organic carbon (DOC) but decreased Eh, affecting Sb redistribution in the rhizosphere–rice system. The Sb fractions were altered with rice growth and the addition of BC. For example, bioavailable Sb increased by 1.57–32.97% in the presence of BC across all rice growth stages. Biochar reduced the BCF and TFR-S of Sb but elevated the TFS-G, indicating that biochar reduced Sb migration from the soil to the rice roots and the rice roots to shoots but increased Sb migration from rice shoots to grains. This study highlights the potential use of biochar as a reclamation agent in remediating Sb-contaminated soils and protecting human health from Sb through the food chain. Full article

Soil environmental protection has become a pressing issue for sustainable development. This study collected 153 topsoil samples from a typical agricultural area to evaluate the contamination characteristics of heavy metal(loid)s (HMs), identify their potential sources, and assess the associated ecological and human health risks. The results showed that the mean concentration of HMs was in the order of Zn > Cr > Ni > Pb > Cu > As > Cd > Hg; all HMs were below their background levels, except Cd. The geo-accumulation index (Igeo) and improved Nemerow index (INI) revealed that the overall pollution level was considered as no or slight contamination, while HMs posed low ecological risk according to the ecological hazard factor (E_i) and potential ecological risk index (PERI). In addition, three main sources were identified through the positive matrix factorization (PMF) model: natural source (48.2%; contributed As, Ni, Cu, Pb, and Zn), coal burning and waste disposal (24%; contributed Hg and Cd), and agricultural activities (27.8%; contributed Cr). The human health risk (HHR) assessment model and Monte Carlo simulation were applied to evaluate human health risks, and the results suggested that children faced higher health risks than adults, with 45.83% of samples exceeding the non-carcinogenic acceptable limit. As and Cr were the main contributors to non-carcinogenic and carcinogenic risks, respectively. The findings contributed to the local environmental management and sustainable development of agriculture. Full article

Contaminated soils are a challenge for implementing biotechnology in bioremediation, the recovery of Critical and Strategic Raw Materials (CRMs and SRMs), and food security. European Union (EU) Governments have established strict limits on As, Pb, Cd, and Hg in foods (Document 32023R0915) and requested the recovery of 34 CRMs within a circular economy (CE) (5th CRMs list). This study proposed a biotechnological tool for the decontamination of soil with heavy metal(loid)s by arbuscular mycorrhizal (AM)-assisted phytoextraction and the subsequent recovery of CRMs or by phytostabilization to prevent their entry into the food chain. It consisted of placing Baccharis salicifolia plants, inoculated or non-inoculated with AM fungi, into bioreactors (BRs) containing mining soil with Cd, Ni, and Cu, according to the Argentinian Patent (AR090183B1). The bioextractive potential (BP) was also estimated at the highest Technological Readiness Level (TRL) using a vegetable depuration module (VDM, TRL 6). Inoculated plants showed significantly higher aerial bioaccumulation coefficients (Cd: 68.62; P: 2.99; Ni: 2.51; Cu: 0.18) in BRs, and the BP values reached 1.16 g, 9.75 g, 2.40 g, and 213.1 g for Ni, Cd, Cu, and P, respectively. Finally, these CRMs and SRMs could be recovered from biomass through hydrometallurgy within a CE framework. Full article

Studies on tollbooth workers involving the concentration of metal(loid)s in highway dust are scarce. We aimed to assess the levels of metal(loid)s in soils and washed and unwashed leaves of Brachiaria decumbens on roadsides. Dust deposition and heavy metal content in the leaves are used to estimate the exposure of tollbooth workers to oral, inhalation, and dermal ingestion of metals in highway dust. The concentrations of aluminum (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), zinc (Zn), and lead (Pb) in washed and unwashed soil and leaves were analyzed using inductively coupled plasma optical emission spectroscopy. The results showed that soils along highways had a high concentration of heavy metals. Concentrations of Cd, Cu, Cr, Ni, and Pb near the roundabout and tollbooth are higher than the concentrations at the points between them. The highest transfer factor values were determined for aluminum. In the case of the non-carcinogenic effect, the hazard index (HI < 1) of tollbooth workers due to oral exposure to street dust containing metal(loid)s is higher than dermal contact and inhalation. The Incremental Lifetime Cancer Risk showed a high potential carcinogenic risk for As and Cd. Full article

This study investigated the characteristics and sources of heavy metal(loid) pollution in the soil of a key industrial park in Kunming, China. In total, 60 soil samples (40 from agricultural land and 20 from construction land) were collected from and around the park. The soil pH and contents of Arsenic (As), lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg), nickel (Ni), and chromium (Cr) were measured. The contents of the eight heavy metal(loid)s were analyzed using the background values of heavy metal(loid)s in the Kunming soil. The pollution load, geoaccumulation, and Nemero Comprehensive Pollution Indices were used for environmental risk evaluation. Cluster and principal component analyses were used to resolve heavy metal(loid) sources. Cd was enriched in construction and agricultural soils. As, Hg, Cd, Pb, Cu, and Zn exhibited large spatial differentiation and were significantly affected by the external environment. A regional pollution load index of 3.02 indicated overall heavy pollution. The pollution load index for each heavy metal(loid) indicated light pollution. The geoaccumulation index indicated relatively severe As, Cd, Cu, Pb, and Zn pollution. The Nemero Composite Pollution Index value showed that the study area was heavily polluted, with construction land being mildly polluted by Cd, and agricultural land being moderately polluted. The results of the spatial distribution show that there were high levels of contamination in the center. Correlation and principal component analyses showed that the pollution sources of the eight heavy metal(loid)s varied. Hg, Cd, and Pb originate primarily from industrial and agricultural pollution. Traffic sources significantly impacted Cu, Pb, Cd, and Cr. Natural sources are the main sources of Cr, Ni, and Cd. Ni is also affected by industrial sources, whereas Zn and Cu are affected by agricultural pollution. The influences of As, Cd, and Pb on the surface soil in the study area were more serious. Cd is more widely polluted and should be a priority in controlling soil heavy metal(loid)s. Full article

Yunnan Province is rich in mineral resources. Early mining, processing, metallurgy, and other mining activities produce three industrial wastes (waste water, waste gas, and waste residue) causing environmental pollution. Considering the legacy site of a mineral processing plant in Yunnan as the research object, 21 sampling points in the study area and 12 control sampling points in the periphery were set up to determine the contents of the heavy metal(loid)s As, Hg, Cd, Cu, Ni, Pb, and Cr in the soil. The spatial distribution of heavy metal(loid)s was interpolated and analyzed using Arcmap10.8, and combined with the single-factor index, Nemero Comprehensive Pollution Index, and the health risk assessment method for the heavy metal(loid) pollution status and health risk of the soil were evaluated. The soil in the study area was acidic, with the largest average value of elemental As and the largest percentages of control and screening values. The results of the single-factor and Nemero composite pollution index showed the following trend: As > Pb > Cd > Cu > Ni > Hg. Cd, Cu, and Pb mainly originate from mining and metallurgy and Hg from the combustion of fossil fuels, while soil-forming substrates are the main sources of Ni. Pollution by As was the most prominent element, whereas pollution by Cd, Cu, and Pb in some areas also cannot be ignored to prevent negative impacts on residents. It is recommended to remediate and treat the soil on site for public events; therefore, this study fills the gap in studying potential ecological risks, human health risk assessments, and sources of exposure (oral ingestion, respiratory ingestion, dermal contact). Full article

Phytoremediation, an ecological approach aimed at addressing polymetal(loid)lic-contaminated mining soils, has encountered adaptability challenges. Dominant plant species, well-suited to the local conditions, have emerged as promising candidates for this purpose. This study focused on assessing the phytoremediation potential of ten plant species that thrived in heavy metal(loid)-contaminated mining soils. This investigation covered nine heavy metal(loid)s (As, Cu, Cd, Cr, Hg, Ni, Pb, Sn, and Zn) in both plants and rhizosphere soils. The results revealed a significant impact of mining activities, with heavy metal(loid) concentrations surpassing the Yunnan Province’s background levels by 1.06 to 362 times, highlighting a significant concern for remediation. The average levels of the heavy metal(loid)s followed the order of As (3.98 × 10³ mg kg⁻¹) > Cu (2.83 × 10³ mg kg⁻¹) > Zn (815 mg kg⁻¹) > Sn (176 mg kg⁻¹) > Pb (169 mg kg⁻¹) > Cr (68.1 mg kg⁻¹) > Ni (36.2 mg kg⁻¹) > Cd (0.120 mg kg⁻¹) > Hg (0.0390 mg kg⁻¹). The bioconcentration factors (BCFs), bioaccumulation factors (BAFs), and translocation factors (TFs) varied among the native plants, indicating diverse adaptation strategies. Low BCFs and BAFs (ranging from 0.0183 to 0.418 and 0.0114 to 0.556, respectively) suggested a low bioavailability of heavy metal(loid)s. Among the species, both J. effusus and P. capitata showed remarkable abilities for As accumulation, while A. adenophora demonstrated a notable accumulation ability for various heavy metal(loid)s, especially Cd, with relatively high BCFs (1.88) and BAFs (3.11), and the TF at 1.66 further underscored the crucial role of translocation in preventing root toxicity. These findings emphasized the potential of these plant species in mine ecological restoration and phytoremediation, guiding targeted environmental rehabilitation strategies. Full article

Hyperspectral remote sensing technology is an advanced and powerful tool that enables fine identification of the numerous soil reflectance spectrum characteristics. Heavy metal(loid)s (HMs) are the primary pollutants affecting the soil biodiversity and ecosystem services. Estimating HMs’ concentrations in soils using hyperspectral data is an effective method but is challenging due to the effects of varied soil properties and measurement-related errors inflicted by atmospheric effects. This study focused on typical mining areas in the Fenwei Plain (FWP), China. Soil-related data were collected by leveraging airborne- and ground-based integrated remote sensing observations. The concentrations of eight HMs, namely copper (Cu), lead (Pb), zinc (Zn), nickel (Ni), chromium (Cr), cadmium (Cd), arsenic (As), and mercury (Hg), were measured by laboratory analysis from 100 in situ soil samples. Soil reflectance spectra were processed based on resampling and envelope methods. The combination datasets of the concentrations and optimal soil reflectance spectra were used to build the soil-related parameter retrieval models using three machine learning (ML) methods, and the feasibility of applying the high-performance retrieval model to estimate the HM concentrations in mining areas was evaluated and explored. Spectral analysis results show that four hundred and twenty-eight bands of five wavelength ranges are of high quality and obviously demonstrate the spectral characteristics selected to build the soil-related parameter models. The evaluation results of eight combination data subsets and three methods show that the preprocessing of spectral data (ground- and airborne-based reflectance) and soil samples with the random forest (RF) method can obtain higher accuracy than support vector machine (SVM) and partial least squares (PLS) methods, denoted as the AER-ACS-RF and GER-GCS-RF models (the average RMSE values of eight HMs were 2.61 and 2.53 mg/kg, respectively). The highest R² values were observed in Cd and As, with an equal value of 0.98, followed by that of Pb (R² = 0.97). The relative prediction deviation (RPD) values of Cu and AS were greater than 1.9. Moreover, the airborne-based AER-ACS-RF model presents a good mapping effect about the concentrations (mg/kg) of eight HMs in mining areas, ranging from 21.65 to 31.25 (Cu), 16.38 to 30.45 (Pb), 62.02 to 109.48 (Zn), 23.33 to 32.47 (Ni), 49.81 to 66.56 (Cr), 0.09 to 0.23 (Cd), 7.31 to 12.24 (As), and 0.03 to 0.17 (Hg), respectively. Full article

Approximately 95% of urban solid waste worldwide is disposed of in landfills. About 14 million metric tonnes of this municipal solid waste are disposed of in landfills every year in Malaysia, illustrating the importance of landfills. Landfill leachate is a liquid that is generated when precipitation percolates through waste disposed of in a landfill. High concentrations of heavy metal(loid)s, organic matter that has been dissolved and/or suspended, and inorganic substances, including phosphorus, ammonium, and sulphate, are present in landfill leachate. Globally, there is an urgent need for efficient remediation strategies for leachate-metal-contaminated soils. The present study expatiates on the physicochemical conditions and heavy metal(loid)s’ concentrations present in leachate samples obtained from four landfills in Malaysia, namely, Air Hitam Sanitary Landfill, Jeram Sanitary landfill, Bukit Beruntung landfill, and Taman Beringin Landfill, and explores bioaugmentation for the remediation of leachate-metal-contaminated soil. Leachate samples (replicates) were taken from all four landfills. Heavy metal(loids) in the collected leachate samples were quantified using inductively coupled plasma mass spectrometry. The microbial strains used for bioaugmentation were isolated from the soil sample collected from Taman Beringin Landfill. X-ray fluorescence spectrometry was used to analyze heavy metal(loid)s in the soil, prior to the isolation of microbes. The results of the present study show that the treatments inoculated with the isolated bacteria had greater potential for bioremediation than the control experiment. Of the nine isolated microbial strains, the treatment regimen involving only three strains (all Gram-positive bacteria) exhibited the highest removal efficiency for heavy metal(loid)s, as observed from most of the results. With regard to new findings, a significant outcome from the present study is that selectively blended microbial species are more effective in the remediation of leachate-metal-contaminated soil, in comparison to a treatment containing a higher number of microbial species and therefore increased diversity. Although the leachate and soil samples were collected from Malaysia, there is a global appeal for the bioremediation strategy applied in this study. Full article

Understanding the contamination and sources of heavy metal(loid)s (HMs) at historical sites is vital for safeguarding human health and the ecological environment. This study focused on As, Hg, Cd, Cu, Pb, Ni, and Cr concentrations in the residual soil, groundwater, and surface water around a mineral processing plant. The sources of these elements and the human health risks posed by them were evaluated using various indexes. Soil HM concentrations exceeded background values for Yunnan Province, ranked as As > Pb > Cd > Cu > Hg > Ni. The river water met China’s Class II waterbody standard; however, Cd, Cu, Pb, and pH exceeded the maximum permissible sewage discharge concentrations in the accumulated water. The groundwater showed severe HM pollution, meeting China’s Class III water quality standard. The average value of the Nemerow pollution index was consistent with that of the single-factor pollution index in the following order: As > Pb > Cd > Ni > Cu > Hg. Children face heightened risk through the oral ingestion of As, Cd, and Pb, particularly in high-value sampling points in the residue deposit area. The main sources of these pollutants are anthropogenic activities and the soil formation matrix. Full article

Heavy metal(loid)s (HMs) in soils near mining sites often cause serious environmental and health issues. Accurately assessing soil HM risks and identifying priority pollutants are crucial for improving risk control efficiency with limited management costs and resources. Traditional deterministic assessments may yield biased results due to the imprecision and ambiguity of environmental data and assessment processes. To compensate for the deficiencies of deterministic assessment, a comprehensive probabilistic-fuzzy model was developed based on fuzzy theory, probability methods, the soil contamination risk (SCR) index, and a human health risk (HR) assessment framework. According to this model, the soil HM risk status in a typical mining area in China was evaluated. The results indicated that Cd and Cu significantly violated the relevant environmental guidelines and were considered priority metals for environmental risk (ER). Notably, Cd’s hazard predominantly manifested in a solid potential ecological risk (PER), whereas Cu’s environmental impact primarily manifested as a soil contamination risk (SCR). From the perspective of HR, soil HMs already pose a considerable threat to human health, with children facing greater HRs than adults. As was identified as a priority element for HRs, with carcinogenic and non-carcinogenic risks reaching unacceptable levels. Regarding general risk (GR), Cd and Cu ranked in the first gradient and As in the second gradient. Overall, the accumulation of soil HMs—especially Cd, Cu, and As—in the study area has posed a significant threat to the ecosystem and human health. The risks of other HMs (Pb, Zn, Cr, and Ni) are relatively low, but the superimposed risks of multiple HMs should not be ignored. The probabilistic–fuzzy model reduces the uncertainty of risk assessment, and the model integrates the environmental and health risks of HMs, providing more comprehensive risk information. The assessment results can serve as a reference for managers to develop targeted control strategies. Full article

Heavy metal(loid)s (HMs) play an important role in economic development since they are used in various branches of industry. However, all industrial activities emit HMs into the environment, where they are no longer useful but potentially toxic. It has been observed that HMs enter the soil and sediment, and potential human health risk may arise due to their excessive accumulation. Having in mind the importance of assessing the risk due to HMs in these media, we analyzed published works in the last decade and created a summary of exposure factors in health risk models for HMs in soil and sediment. This analysis revealed a remarkable increase in the number of publications about health risk assessment of HMs, especially in the last few years. Since many differences in the values of the exposure factors and their distributions were noted, this study focused on elucidating these differences. Non-carcinogenic and carcinogenic health risk assessment models were evaluated through a deterministic approach that is prevalent in use, and a probabilistic one, which is gaining more and more attention in research. In the end, guided by the studied literature, we propose the values and distributions for the exposure factors. Full article

In Pakistan, wastewater such as industrial and urban wastewater is widely used for agricultural irrigation despite its chemical and pollutant content. In this respect, it is important to determine the risks of heavy metal accumulation in various agricultural products and the risks to human health. The aims of this study were to assess the heavy metal(loid)s contamination in soil and sugar beet samples and to assess the health risks of heavy metal(loid)s to the population via the consumption of sugar beet. The heavy metal(loid) values in the wastewater-irrigated soil samples ranged from 0.260 to 4.053 mg/kg, and wastewater-irrigated sugar beet samples ranged from 0.051 to 1.666 mg/kg. In contrast to Cd, Ni, Cu, Fe, Mn, Cr and Zn, which appeared to pose a health risk, Pb, Co, and Cr had Health Risk Index (HRI) values lower than 1.0 and did not appear to pose a threat to human health. Cd accumulation with HRI values over 1 (144.8) indicated that this metal is likely to have a major negative impact on local health. Full article