Search Results (2,564)

The accumulation of microplastics (MPs) in agricultural soils and atrazine in agricultural soils creates compound pollution that severely threatens soil health. The present study aimed to evaluate the effect of polyethylene (PE), polyvinyl chloride (PVC), and polybutylene succinate (PBS) on the adsorption and degradation of atrazine in yellow-brown and black soil. Batch adsorption kinetic and isotherm experiments were conducted in two distinct soils amended with MPs. A 90-day degradation experiment was performed to monitor atrazine persistence and the activities of key soil enzymes. The adsorption process was best described by the pseudo-second-order model and the Freundlich isotherm model, suggesting dominant chemisorption and multilayer adsorption on heterogeneous surfaces of the soil–MP composites. All MPs significantly enhanced the adsorption capacity for atrazine (6.80–39.93 mg kg⁻¹), with the order PBS > PE > PVC. Furthermore, the degradation of atrazine was impeded by all MPs, with PVC exhibiting the strongest inhibitory effect. The half-life of atrazine ranges from 22.97 to 81.76 days in two soils. The presence of MPs also influenced soil enzyme activities and the effects varied by MP type and soil property. These results demonstrate that MPs can modify the adsorption and persistence of atrazine in soil, thereby increasing its environmental risk. This study provides valuable insights for the long-term ecological risk assessment of co-existing MPs and pesticide pollution in terrestrial environments. Full article

Industrial activities have caused heavy metals, such as cadmium (Cd), chromium (Cr), lead (Pb), and copper (Cu), to seriously threaten groundwater safety through seepage pathways. This study explored the formation of biofilms using microbe-induced calcium carbonate precipitation (MICP) technology to simultaneously reduce seepage in contaminated water and immobilize heavy metals. By optimizing the cementation fluid concentration and the intermittent grouting time, the optimal operating conditions for forming a biofilm were determined to be 1.5 mol/L cementation fluid and an intermittent time of 12 h, under which the stable infiltration rate of the sandy loam soil column can be reduced by more than 80%. We found that this biofilm can effectively inhibit the convective transport of Cd, Cr, Pb, and Cu, with the cumulative convective flux reduction rates reaching 56.25%, 56.25%, 54.54%, and 55.59%, respectively. SEM and XRD analysis indicate that the physical blockage of soil pores by calcium carbonate crystals is the dominant mechanism controlling infiltration flow, while the detection of new mineral phases, such as lead carbonate (PbCO₃), cadmium carbonate (CdCO₃), and basic copper carbonate (Cu₂(OH)₂CO₃) provides direct evidence for the chemical co-precipitation immobilization of heavy metals. This study demonstrates that MICP biofilm is a green and sustainable technology for in situ remediation of heavy metal pollution through physical–chemical synergistic effects, offering a promising alternative with a lower environmental footprint compared to conventional methods. Full article

Soil heavy metal contamination poses a major environmental threat, negatively impacting ecosystems, agricultural productivity, and human health. Phytoremediation offers eco-sustainable alternatives to conventional remediation techniques by employing plant species capable of extracting and stabilizing pollutants. This study assesses the potential of Cannabis sativa L. var. ‘Carmagnola’ for the remediation of Pb, Cr, Cu, and Ni from four different growth substrates. This species was selected for its high biomass yield, tolerance to toxic environments, and capacity for heavy metal accumulation. Experimental results showed that the composition of the growing substrate significantly affected HM uptake, with higher accumulation occurring in less compact mixed substrates. HM removal from contaminated growth substrates varied between 55 and 75% for Cr, 60–78% for Ni, 32–86% for Cu and 43–84% for Pb after four months of growth in a greenhouse environment. In addition to pollutant removal efficiency, the study explored thermochemical harvested biomass post-processing via pyrolysis in order to produce biochar, a material with recognized agronomic beneficial properties and positive environmental value. Biochar generated from harvested biomass after phytoremediation tests showed residual HM content lower than the applicable EU thresholds for agricultural soil amendment. Integrating bioremediation with biochar production can promote a circular bioeconomy approach to environmental restoration, by transforming contaminated residual biomass into a useful resource rather than waste. These findings support the feasibility potential of coupling C. sativa phytoremediation and biochar production as an environmentally sustainable strategy for large-scale remediation of heavy metal-contaminated soils. Full article

This study provides a comprehensive assessment of 12 metal(loid)s in the muscle tissue of the commercially vital shrimp, Penaeus semisulcatus, from four stations (Bozyazi, Silifke, Karatas, and Iskenderun) along the Northeastern Mediterranean. Metal concentrations were evaluated separately for males and females, utilizing Estimated Weekly Intake (EWI), Target Hazard Quotient (THQ), Carcinogenic Risk (CR), and Selenium Health Benefit Value (HBV_Se) indices. While the species is generally safe for consumption across the region, a striking, localized bioaccumulation of Chromium (Cr) was identified specifically in Iskenderun Bay, where male shrimps exhibited concentrations (1.209 mg/kg wet weight) approximately 10-fold higher than females, highlighting a sex-specific sensitivity likely linked to metabolic and physiological differences. By adopting a precautionary risk assessment framework—considering the region’s intense industrial profile—this localized spike resulted in a Total Carcinogenic Risk (∑CR = 5.15 × 10⁻⁴) for this group, exceeding the priority threshold. Furthermore, widespread Lead (Pb) contamination was detected across all stations, with several samples surpassing EU maximum levels (0.50 mg/kg). Regarding Arsenic (As), while high total concentrations led to THQ values > 1 across the regional gradient, this was characterized as a conservative modeling artifact rather than a physiological threat, as Arsenic in crustaceans is predominantly in the non-toxic organic form. Conversely, any potential risk from Mercury (Hg) was conclusively mitigated by an overwhelming molar excess of Selenium (Se) at all locations, confirmed by consistently positive HBV_Se values (0.312–0.658). In conclusion, our findings demonstrate that seafood safety is conditional and region-specific. The study underscores that localized contamination “hotspots” can be easily masked by non-sex-specific sampling and emphasizes the necessity of moving beyond simplistic risk models by incorporating selenium-mercury antagonism and precautionary risk assumptions for industrial pollutants. Full article

Municipal solid waste incineration (MSWI) fly ash is classified as hazardous waste due to its enrichment of heavy metals and dioxins. This article systematically reviews its generation pathways, physicochemical characteristics, and potential environmental risks, based on the literature from 2010 to 2025 sourced from Web of Science, Scopus, ScienceDirect and China National Knowledge Infrastructure. Emphasis is placed on heavy metal stabilization, dioxin degradation and resource recovery from MSWI fly ash. The mechanisms, technical advantages, and application limitations of three mainstream detoxification, including solidification/stabilization, extraction and thermal treatment, were emphasized. For instance, geopolymer achieves >99.6% Pb immobilization and electrodialytic removal rates of Cd up to 98%, while vitrification reduces the MSWI fly ash volume by >50%. A comprehensive exploration of MSWI fly ash resource utilization was conducted, covering the preparation of ceramic tiles, synthesis of glass ceramic and glass ceramic foams, processing of road substrates, and modification of cement-based composite materials. The current technological system still faces challenges such as high costs, excessive energy consumption, and secondary pollution. Future research should focus on developing green, low-carbon, and low-cost processes, improving long-term environmental stability of products and strengthening pollution source reduction control. Full article

While mining is a highly important economic activity, it generates considerable environmental impact, especially during the grinding and extraction stages of metallic minerals, leading to the formation of waste known as mine tailings. These mine tailings, often abandoned in various regions of Mexico due to a lack of prior environmental regulations, contain heavy metals that pose a risk to both the environment and human health. In Huautla, Morelos, where metals such as silver (Ag), gold (Au), copper (Cu), lead (Pb), and zinc (Zn) were extracted from the 16th century until 1988, it is estimated that there are approximately 780,000 tons of mine tailings. These mine tailings are contaminated with heavy metals such as cadmium (Cd), Cu, chromium (Cr), manganese (Mn), Pb, and Zn, and the bioaccumulation and biomagnification of these metals have been documented in various plant and animal species in the region, indicating their bioavailability. The study conducted in this area consisted of determining the concentration of Cd, Cu, Cr, Mn, Pb, and Zn, as well as the sequential extraction of mine tailings 1 and 2 to identify metal bioavailability. The results showed for both mine tailings, that the metals with the highest concentrations were Pb (mine tailing 1: 1666 ± 317.7 mg/kg, mine tailing 2: 1329 ± 30.8 mg/kg) and Zn (mine tailing 1: 1327 ± 314.9 mg/kg, mine tailing 2: 1099 ± 34.3 mg/kg), found in fractions IV and VI, respectively. In mine tailings 1, the main bioavailable metals were Cd (75.3%), Mn (53%), Pb (39.8%), and Cu (36.4%), while in mine tailings 2, the bioavailable metals were Cd (56.8%), Pb (37.9%), and Cu (29.3%). In general, Cd and Pb exhibited the highest bioavailability in both mine tailings. According to the calculated risk indices, bioavailable Cd and Pb pose the highest pollution, ecological, and non-carcinogenic risk in both mine tailings, while bioavailable Cr showed the highest determined carcinogenic risk. This study demonstrated that the mining waste from Huautla contains high levels of bioavailable heavy metals, posing ecological and public health risks, and provides valuable information for the development of effective environmental remediation strategies. Full article

Heavy metal contamination of surface waters poses serious environmental and public health concerns, particularly in industrialized river basins. This study presents an integrated assessment of heavy metal pollution and associated human health risks in the Nilüfer Stream (Bursa, Türkiye) based on a five-year monitoring dataset (2020–2024). Seasonal water samples collected from 15 stations along the main stream and its tributaries were analyzed for total concentrations of As, Al, B, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Pollution levels were evaluated using the Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), and Degree of Contamination (Cd), while non-carcinogenic and carcinogenic health risks for adults and children were assessed via ingestion exposure following USEPA guidelines. Mean concentrations of Al, Fe, Mn, As, and Ni exceeded international drinking water guideline values, indicating significant contamination within the basin. All indices classified the Nilüfer Stream as severely polluted (HPI = 274.32; HEI = 49.59; Cd = 49.59), with higher values during summer and autumn due to reduced dilution. Principal component analysis revealed strong associations among Al, Fe, Mn, Ni, Cr, and Cu, suggesting a common origin likely related to cumulative anthropogenic inputs, while arsenic exhibited a distinct pattern linked to toxicological risk. Health risk assessment showed that the hazard index exceeded safe thresholds for both age groups, with children being more vulnerable. Arsenic and nickel were the main contributors to both non-carcinogenic and carcinogenic risks, with arsenic posing an unacceptable lifetime cancer risk. Overall, the results indicate severe cumulative heavy metal pollution and associated health risks, highlighting the need for continuous monitoring, effective pollution control, and integrated river basin management. Full article

Heavy metals in urban dust, derived from anthropogenic activities and natural sources, are considered potentially toxic elements for human health. The city of Puebla, located in Central Mexico, is one of the ten largest metropolitan cities in Mexico. Near this city is the Popocatépetl volcano, which contributes heavy metals through the emission of ash. The objectives of this study were to evaluate heavy metal contamination in urban dust and volcanic ash from the city of Puebla, and to determine the associated human health risks. Heavy metals were analyzed using an XRF spectrometer. The level of contamination was established according to the contamination factor, the geoaccumulation index and the contaminant load index. Furthermore, non-carcinogenic risk indices (HIs) were calculated to evaluate the health risk. The results revealed the presence of 18 elements (Ca, Cr, Cu, Fe, K, Mn, Nb, Ni, Pb, Rb, Sb, Sn, Sr, Ti, Y, V, Zn and Zr), with the highest concentrations found for most in urban dust samples, while Rb, Ca and K showed higher concentrations in ash samples. High levels of Sb and Sn contamination were found in 90 to 100% of the dust and ash samples, while Cr, Cu, Ni, Pb and Zn showed considerable levels of contamination in 60 to 90% of the samples. According to the US EPA thresholds, the health risk assessment indicated safe levels (HI < 0.25) for Cu, Fe, Mn, Ni, Pb, Sn, V and Zn in the urban dust and volcanic ash samples, while some of the samples exceeded the safety threshold (HI > 1) for Cr and Sb with respect to the child population in the city of Puebla. These results must be taken into consideration by environmental and government authorities, and the degree of pollution should be reduced accordingly. Full article

High-altitude mine wastelands in Southwest China present formidable challenges for ecological rehabilitation due to extreme climatic stressors and multi-element contamination. Ecological restoration is closely related to soil environment. However, the mechanism by which parent material-induced heterogeneity governs spontaneous vegetation succession is still poorly understood. We established 36 plots (216 quadrats) to investigate the soil physical and chemical properties and vegetation restoration of propylite, porphyry and siltstone in the Xifanping Copper Mine, Sichuan Province. Furthermore, fifteen metal/metalloid elements (Au, Ag, Mo, W, Cu, Pb, Zn, Hg, As, U, Se, Cr, Sn, Ti, Total Fe₂O₃), soil pollution and vegetation structure were evaluated. The study area exhibited severe composite pollution (mean Nemerow integrated pollution index = 8.09), primarily driven by Au, Ag, Mo, W, and Cu. Vegetation surveys identified 34 vascular plant species from 12 families. Propylite-derived substrates supported significantly higher species richness, Shannon–Wiener diversity, and soil organic matter than porphyry and siltstone. Redundancy analysis (RDA) identified soil organic matter (SOM) and bulk density (BD) as dominant environmental filters, with SOM explaining 14.03% of community variance (p < 0.01). Two native pioneers, Potentilla supina and Cynoglossum wallichii, were identified as specialized uranium (U) accumulators with bioconcentration factors of 13.39 and 4.49, respectively. Lithological inheritance dictates early successional trajectories by influencing edaphic structure and nutrient bioavailability. The identified U-accumulating species provide a valuable genetic resource for implementing Assisted Natural Regeneration (ANR) and developing sustainable phytoremediation strategies in contaminated alpine ecosystems. Full article

The assessment of metal contamination in aquatic species represents an important tool to monitor the risk of exposure for these species in relation to marine pollution. Crabs are the sentinel species of the aquatic environment and are very sensitive to metal exposure because these inorganic contaminants can be easily absorbed into their exoskeleton and migrate into their inner tissues. The aim of this study was to assess the content of metals and metalloids (Hg, Pb, Cd, As, Cr, Mn and Ni) in species of warty crab (Eriphia verrucosa), brown crab (Cancer pagurus), and marbled crab (Pachygrapsus marmoratus), mainly distributed along the Mediterranean coastlines. The investigations, carried out on several parts of crabs (carapace and the related pulp, gills, claws and bronchial muscle) showed the presence of residual levels of metals and metalloids (Mn > Pb > Hg > As > Ni > Cr > Cd), correlated to the distribution of these elements in the marine environment and to the specific biological features of crabs. However, the values of Metal Pollution Index (MPI) suggested a low level of contamination of the marine ecosystem where these species were found, and the coefficient of correlation (K), a specific parameters of toxicological risk assessment, was indicative of crab health status. However, the residual levels of Hg, Pb and As above the MRL in all analyzed crab species underlined the importance of continuous monitoring studies on the safety of these sea-foods. Full article

Bioretention systems are increasingly implemented as green infrastructure for urban stormwater management. However, their long-term performance is jeopardized by the continuous accumulation of potentially toxic metals in substrates and vegetation, posing significant risks to ecosystem health and human safety. Despite their growing application, the mechanisms driving metal dynamics and plant responses within these systems remain poorly understood. This study conducts a comprehensive multi-factor investigation into the accumulation, mobility, and biological impacts of four representative potentially toxic metals (Cd, Cu, Zn, and Pb) in bioretention soils and vegetation. Through controlled mesocosm experiments, we quantified metal concentrations in soils and three plant species, analyzed alterations in the physical and chemical properties of soil, and assessed plant physiological stress responses. Metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS), and statistical analyses were conducted using one-way ANOVA (p < 0.05). Cadmium exhibited the highest enrichment, with plant uptake increasing by 330.0% to 563.2%, especially in Iris tectorum Maxim., which demonstrated superior phytoaccumulation potential. Conversely, Ophiopogon japonicus Ker Gawl. showed remarkable tolerance to metal-induced stress, maintaining stable levels of chlorophyll content, photosynthetic rate, peroxidase activity, and soluble sugar concentration. Notably, the incorporation of humic substances significantly enhanced metal immobilization in soil, while simultaneously reducing plant uptake and physiological stress, revealing a promising strategy for toxicity mitigation. By integrating the effects of plant species, substrate composition, and influent concentration, this study provides novel insights into the complex interactions governing pollutant fate in bioretention systems. The findings offer critical guidance for optimizing bioretention design and management to ensure sustained pollutant removal efficiency and ecological resilience in urban stormwater treatment. Full article

This study investigated the combined effects of leaching agents and iron distribution on the migration behavior of pollutants in municipal solid waste incineration bottom ash (MSWI-BA). A column leaching experiment was designed where the control group (CK) employed deionized water with uniformly distributed iron. This baseline was systematically compared against treatment groups involving two leaching agents (Na₂CO₃, Na₂SO₄) and three iron distribution scenarios (Top, Bottom, and Removal). Compared to the CK, the introduction of Na₂CO₃ significantly intensified pollutant mobilization: the abundance of microplastics (MPs) increased by 49.33%, chloride leaching rose by 189.99%, and heavy metal (HM) concentrations (Cu, Cr, Pb, As) surged by 2.0–40.6 times. Furthermore, iron distribution played a critical regulatory role; specifically, manipulating iron placement further elevated MP abundance by 80.2% and chloride leaching by 191.03%. Morphological analysis indicated that MPs primarily existed as transparent or yellow particles, films, and fibers, characteristics that remained stable across treatments. Crucially, these findings offer engineering insights for real-world scenarios: retaining a bottom iron-rich layer during stockpiling can act as a reactive barrier to intercept pollutants, whereas carbonate-rich landfill environments require pH-buffering to mitigate MP co-migration. This study provides a theoretical basis for optimizing pretreatment processes (e.g., coordinated washing and magnetic separation) to ensure the safe resource recovery of BA. Full article

Soil heavy metal contamination in mining areas poses a serious environmental challenge, requiring monitoring approaches with both wide coverage and high accuracy. Hyperspectral remote sensing provides an effective solution, yet its performance in complex mining environments is often limited by mixed-pixel effects and nonlinear spectral responses. To address these issues, this study proposes a Physically-Constrained Collaborative Endmember Extraction (PCCEE) framework that integrates spectral unmixing with machine learning for multi-element inversion. Using Gaofen-5 hyperspectral imagery, a collaborative workflow combining Pixel Purity Index (PPI), Vertex Component Analysis (VCA), and prior-spectral-constrained Spectral Angle Mapper (SAM) was developed to improve endmember purity and physical interpretability. Among three unmixing models (LMM, NMF, and SVR), the Linear Mixing Model achieved the best balance between accuracy and efficiency. Random Forest regression using retrieved abundances enabled high-accuracy inversion of eight heavy metals (mean R² = 0.85). Spatial analysis revealed significant co-enrichment of Pb, Cd, and Zn related to sulfide weathering, while PCA distinguished compound and independent pollution sources. The proposed PCCEE framework effectively mitigates mixed-pixel interference and provides a transferable approach for heavy metal monitoring and risk assessment in complex mining environments. Full article

Peach tree (Prunus persica L. Batsch) is a fruit species of great economic importance worldwide. Thousands of chemical leaf analyses are performed on a yearly basis to support decision-making about fertilizer application. However, traditional methods to determine nutrient content in plant tissue require a mix of strong acids, besides being time-consuming and generating polluting waste. Visible (Vis) and near-infrared (NIR) spectroscopy combined with multivariate techniques emerges as a potential solution to overcome limitations of traditional chemical analyses. The aim of the present study is to combine Vis-NIR spectral data and multivariate techniques to test strategies for the development of models to estimate nutrient content in peach leaves. The study estimated N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn content in the leaves of peach trees grown in two locations, namely: Pelotas and Pinto Bandeira, in Southern Brazil. Therefore, local and regional scale prediction models were developed by combining preprocessed Vis-NIR spectral data to both Savitzky–Golay first-derivative (SGD1d) and partial least squares regression (PLSR) multivariate technique. Most of the proposed prediction models showed average accuracy (R² ≥ 0.50 and <0.75, RPIQ ≥ 1.9 and <3.0). The local-1 ‘PB’ model showed higher nutrient prediction accuracy than the regional ‘PB + Pelotas’ model and the local-2 ‘Pelotas’ model. Estimates on nutrient content in peach tree leaves subjected to local, local-1 ‘PB’ and local-2 ‘Pelotas’ models fed with data collected in the same site showed better performance than calculations based on data from other sites and/or regions. Finally, the current study allowed making updates in the refinement of more sustainable techniques to set nutrient content. Full article

Trace metal contamination in lotic freshwater systems exhibits pronounced heterogeneity arising from coupled hydrological connectivity, geochemical partitioning, and anthropogenic forcing, complicating exposure characterization in urban and peri-urban catchments. Addressing this complexity requires integrative analytical approaches capable of deciphering system-level controls, prompting an investigation of the environmental structuring and governing controls of dissolved trace metal signatures in a human-impacted stream using a system-oriented computational framework. To capture temporal variability associated with seasonal hydrological contrasts and heterogeneous pollution inputs, a station-based, season-resolved sampling strategy was implemented during the wet and dry seasons. Physicochemical gradients (pH, temperature, dissolved oxygen, and electrical conductivity), inorganic nitrogen species (NH₃, NO₂⁻, and NO₃⁻), and phosphorus fractions (total phosphorus, TP; total orthophosphate, TOP; soluble reactive P, SRP) were jointly analyzed with dissolved concentrations of chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). Regression-based machine learning models were used to quantify element-specific sensitivities to hydrochemical drivers under wet–dry periods and to identify optimal predictive configurations. Predictive performance was consistently high for trace metals (R² generally >0.95), with Random Forest providing the best accuracy for Cr, Ni, Pb, Cd, As, and Hg, whereas Cu was most reliably captured by an XGBoost tree ensemble (R² = 0.994). Explainability analyses revealed heterogeneous, metal-specific control regimes: Cr was primarily driven by temperature, Ni by NO₂⁻ and redox-sensitive conditions, Cd by NH₃ and temperature, and As by Hg in combination with phosphorus-related and redox-linked proxies, while Pb showed comparatively lower predictability relative to other metals. Trace metal distributions are therefore structured primarily by differential environmental sensitivity rather than uniform source-driven inputs, reinforcing the need for integrative computational frameworks when interpreting freshwater contamination under intensifying anthropogenic and climatic pressures. Full article