Environmental Geochemistry and Health最新文献

Pharmaceutical contamination of aquatic systems poses an increasing environmental concern due to the persistence, bioactivity, and incomplete removal of these compounds by conventional wastewater treatment processes. This study investigates the adsorptive removal of three structurally distinct pharmaceuticals: ketotifen fumarate (KF), doxycycline hyclate (DXC), and nystatin (Nyst), using raw bentonite (RB). By combining batch experiments with an interpretable machine learning (ML) framework, adsorption kinetics, equilibrium, and thermodynamics were evaluated. Additionally, four Ant Lion Optimizer (ALO)-optimized models: Artificial Neural Network (ANN), Support Vector Regression (SVR), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost), were employed to predict adsorption capacity under diverse conditions. RB exhibited high adsorption capacities: 178.86 ± 1.26 mg/g for KF, 222.91 ± 2.02 mg/g for DXC, and 190.25 ± 2.86 mg/g for Nyst. Adsorption equilibrium was best described by the Freundlich isotherm, indicating multilayer adsorption on a heterogeneous surface. Thermodynamic and spectroscopic analyses revealed a dual mechanism involving electrostatic attraction, hydrogen bonding, cation exchange, and van der Waals interactions, with DXC and Nyst adsorption being endothermic and KF adsorption exothermic. SHAP (SHapley Additive exPlanations) analysis identified adsorbent dosage, initial concentration, and pH as dominant operational factors, while the molecular descriptor nC (number of carbon atoms) emerged as key to differentiating pharmaceuticals, linking larger molecular size to stronger adsorption. The XGBoost model achieved the highest accuracy (R² = 0.972, RMSE = 0.1225), demonstrating robust generalizability. These findings highlight RB as a low-cost, scalable adsorbent and establish an interpretable ML approach capable of linking molecular structure to adsorption behavior.

This work represents the first integrated assessment in the Litani River Basin, Lebanon's longest river, which flows into the Mediterranean Sea, combining multi-class organic micropollutant occurrence, specifically pharmaceuticals and aromatic hydrocarbons, in both surface water and sediment with a quantitative environmental risk assessment. Surface water and sediment samples were collected across consecutive dry (summer) and wet (winter) seasons from nine sites along the Upper Litani River Basin and analyzed using advanced analytical methods. Among the 27 tested pharmaceuticals, ibuprofen (4.7 µg/L), caffeine (23.6 µg/L), telmisartan (833.5 ng/L), carbamazepine (658.5 ng/L), gemfibrozil (71.0 ng/L), mefenamic acid (64.7 ng/L), and diphenhydramine (65.9 ng/L) were the most frequently detected, with some reaching notably high concentrations in the µg/L range in surface water. Sediments revealed ubiquitous contamination by ibuprofen, telmisartan, climbazole, diphenhydramine, and azithromycin. Spatial profiling identified pollution hotspots closely linked to the discharge of untreated municipal sewage, and hospital and industrial effluents. Environmental risk assessment results highlighted substantial ecological risks posed by telmisartan, ibuprofen, diclofenac, climbazole, and caffeine. Among the aromatic hydrocarbons, xylene, ethylbenzene, and benzene were frequently detected in the sediments at ecologically hazardous concentrations, while naphthalene and benzo[a]pyrene exhibited seasonal and spatial variability in occurrence and risk potential. The findings from this study contribute to the state of knowledge of pollution levels of emerging contaminants in a major Mediterranean river and permit to inform and guide future mitigation and management strategies. The environmental risk assessment applied in this study enabled the translation of measured concentrations into ecologically meaningful indicators allowing the identification of priority contaminants and high-risk locations.

With rapid urbanization and industrialization, pollution of rare earth elements (REEs) in air, soil, and water is increasing in urban areas. These critical high-tech elements are becoming more abundant in urban dust and other environmental settings. It is difficult to differentiate and quantify the sources of REE pollution, as natural and anthropogenic sources overlap. This work couples isotopic tracing techniques (Pb, Sr, and Nd isotopes) with receptor models (positive matrix factorization (PMF) and absolute principal component scores/multiple linear regression (APCS/MLR)) to obtain robust source apportionment of REEs in urban environments. Isotopic fingerprints, including Gd anomalies, have been shown to serve as powerful tracers for distinguishing vehicular emissions, industrial discharges, and soil erosion. Non-exhaust vehicular emissions, especially those from brake and tire wear, have been identified as the main sources of REE release into the environment. The combination of isotopic methods and receptor models enhances the accuracy of source apportionment and contributions, facilitating better environmental management. The review highlights the need for standardized isotope libraries and sophisticated modelling tools to characterize sources, thereby improving source apportionment and informing sustainable control strategies for urban pollution. Focusing on controlling industrial and vehicle emissions can be an effective strategy to reduce REE contamination levels and human exposure.

Urban uncontrolled landfills in Kinshasa generate metal-rich leachates that contaminate surrounding freshwater streams, sediments, and biota. To assess the extent of this contamination, sediment from six freshwater streams in Kinshasa (N'djili, Limete, Lemba, Selembao, Mont-Ngafula, Makala) were analyzed to assess contamination by heavy metals-including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sn, Sb, Pb and Hg-and bioaccumulation in terrestrial (Lumbricus terrestris) and aquatic (Tubifex tubifex, Nais elinguis, Enchytraeus albidus) oligochaetes. Sediments were digested following the Swiss Federal Soil Ordinance (OSol 814.12) and analyzed using ICP-MS for metals and a Direct Mercury Analyzer (CV-AAS) for total Hg. Oligochaete tissues were freeze-dried, acid-digested (HNO₃-HClO₄), and analyzed using the same instrumentation. Sediment pollution levels were assessed using the Geoaccumulation Index (Igeo), Enrichment Factor (EF), contamination factor (CF), and the overall Ecological Risk Index (RI), while ecological thresholds were compared to the Canadian Sediment Quality Guidelines. Bioaccumulation factors (BAF) were calculated to quantify metal transfer from sediments to organisms. Sediments showed strong contamination at landfill-impacted sites, with Hg reaching 3.8 mg·kg⁻¹ dry weight-far exceeding Canadian SQGs (TEL: 0.17 mg·kg⁻¹) and PELs (0.486 mg·kg⁻¹). Cu and Zn were also highly elevated (up to 687.9 and 995.3 mg·kg⁻¹, respectively). RI values were highest at Limete (1014-3552.7), indicating very high ecological risk. Aquatic oligochaetes exhibited greater bioaccumulation than terrestrial species, with Hg up to 0.876 mg·kg⁻¹ and Cu up to 93.1 mg·kg⁻¹. High BAFs were observed, particularly for Cd (118.2 at Mont-Ngafula) and Sn (263.1 at Makala), confirming strong sediment-to-organism transfer. Fine, organic-rich sediments and proximity to landfill leachates were positively correlated with metal contamination and bioavailability.

This study investigated the hydrogeochemical characteristics of surface waters in the Congonhas Mineral District (CMD), located in the southern portion of Quadrilátero Ferrífero, Brazil. A total of 38 sites were monitored between 2021 and 2024 to understand seasonal and spatial variability across distinct lithologies and land uses. Hydrogeochemical patterns revealed dominant mixed bicarbonate facies associated with metavolcano-sedimentary terrains, while domains of granitoids exhibited alkali enrichment. Waters under the influence of larger Urban settlements were enriched in Na, Cl, sulfate, and nutrients. By integrating geospatial classification, seasonal sampling, and robust statistical techniques, we investigated the behavior of Fe and Mn, key elements influenced by both natural geological sources and mining activities. Reference values for geochemical background and baseline thresholds, based on samples from preserved and mixed land use areas, respectively, were estimated using three distinct statistical approaches. Among these, the upper tolerance limit (UTL) method was considered the most consistent and suitable. Spatial and seasonal patterns revealed elevated Fe and Mn levels during the rainy season, particularly in areas influenced by mining and urbanization. The proposed reference values provide a realistic basis for identifying contamination, and can give support for more realistic regulatory frameworks, and definition of strategies for water quality management. The obtained results highlight the relevance of tailored guidelines in mining contexts, where reference values adopted by regulatory agencies may not reflect local geochemical conditions.

Cadmium (Cd) pollution poses a serious threat to aquatic environmental safety and sustainable agricultural development. Biogenic iron (Fe)-manganese (Mn) oxides (BFMO), mediated by Mn-oxidizing bacteria, are promising natural adsorbents for Cd removal. Although iron-manganese oxides have been widely studied for application in wastewater treatment, BFMO synthesized via a fully biologically driven process using novel strains still face limitations in terms of material structure and the availability of active sites. In this study, BFMO was synthesized using a newly isolated strain of Stenotrophomonas sp. Z-MRQA-3, and its mineralogical properties, Cd(II) immobilization performance, and underlying mechanisms were systematically investigated. The results demonstrated that BFMO possesses a high specific surface area (244.52 m²/g), a hierarchical porous structure, and abundant surface functional groups, which collectively contribute to its superior adsorption capacity. Under conditions of adsorbent dosage of 0.5 g/L, initial Cd(II) concentration of 50 mg/L, and pH 7.2, the removal efficiency of Cd(II) reached 96.52%, with an adsorption capacity of 80.83 mg/g. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, with a theoretical maximum adsorption capacity of 89.29 mg/g. Mechanistic studies indicated that Cd(II) immobilization occurs mainly through surface complexation, ion exchange, and co-precipitation, facilitated by the redox-active multivalent Mn and oxygen-containing functional groups. This study aims to investigate the unique advantages of in situ synthesizing BFMO using specific bacterial strains. This work offers fundamental insights and practical prospects for developing green, efficient, and sustainable technologies for remediating Cd-contaminated water.

The socio-economic constraints-driven under provision of scientifically designed landfills for effective management of hazardous industrial wastes like tannery solid waste (TSW) in the developing countries. Disposal of TSW at designated and non-designated open dumps (OD) renders seasonal leachate runoff into adjacent agricultural fields when intense precipitation hits mountainously stacked TSWOD during summer and winter monsoon. However, TSWOD driven impacts on soil and crop productivity and biosafety of the adjacent agricultural fields has been missing in the literature. The objective of the current study was spatiotemporal quantification of productivity and biosafety threats of seasonal TSW leachate to recurrent corn and potato food crops in the adjoining agricultural fields of TSWOD of combined effluent plant of KTWMA, Kasur Pakistan. Based on data collected from two agricultural fields (2 ha each), it was observed that: (1) the TSW leachate arising from TSWOD severely affected soil productivity potential due to its immoderate pH, EC, COD, and BOD; being significantly higher than the local irrigation water; (2)Cd, Cr. Cu, Mn, Ni, Na and K in the TSW leachate exceeded the provincial industrial effluent discharge limits and had significant impact on soil health than the non-polluted fields; (3) the productivity of corn and potato in polluted fields remained as low as one third of the productivity in non-polluted fields; (4) the environmental contaminants' food biosafety hazards were determined as metal pollution index being variable for different metals, hazard index (HI < 1.0), and risk quotient (chronic risk with 1.0 level of concern). (4) Statistically, the productivity decline of corn and potato crops was function of the changes in soils chemistry. The study concluded that TSWOD seasonal leachate increasingly reduced suitability of adjoining soils for safer edible cropping by significantly reducing productivity and posing long-term biosafety hazards caused by vulnerability of food chain to heavy metals and organic pollutants.

Agroecosystems, which sustain global food production and economic stability, face increasing threats from emerging contaminants such as microplastics, Per- and polyfluoroalkyl substances (PFAS), pharmaceuticals, and engineered nanomaterials (ENMs). These pollutants persist in the environment, bioaccumulate in crops, and impose complex risks to soil health, biodiversity, and human well-being. Microplastics derived from agricultural plastics and sewage sludge disrupt soil structure and microbial communities, while PFAS migrate into groundwater and contaminate drinking water supplies. Pharmaceuticals introduced through wastewater irrigation and manure application accelerate antimicrobial resistance, and ENMs used in agrochemicals influence nutrient dynamics and soil chemistry. Despite growing recognition of these hazards, regulatory responses remain fragmented and current risk-assessment frameworks insufficient. This review synthesizes advanced detection tools-including CRISPR-based biosensors, machine-learning contamination mapping, and high-resolution spectroscopy-with sustainable remediation strategies such as phytoremediation, biochar amendments, and nano-enabled pollutant degradation. By comparing emerging contaminants with conventional pollutants, this work establishes their unique persistence, mobility, and policy challenges while linking their impacts to Sustainable Development Goals (SDGs) 2, 3, and 6. Importantly, the review emphasizes that long-term resilience of agroecosystems requires coordinated global policy alignment, integration of interdisciplinary monitoring systems, and stakeholder engagement to reduce contaminant loads. Future research should prioritize harmonized toxicity thresholds, long-term field experiments on contaminant-crop interactions, and scalable, low-cost detection platforms suitable for resource-limited regions. Together, these efforts will be essential for mitigating EC-related risks, strengthening food security, and safeguarding environmental and public health.

Minerals containing iron (Fe) and phosphate can simultaneously immobilize cations such as lead (Pb) and oxyanions including arsenic (As) and antimony (Sb). However, phosphate released from these minerals substitutes for adsorbed As and Sb and increases metal(loid) mobility, which limits their practical effectiveness. Vivianite [Fe₃(PO₄)₂·8(H₂O)], an Fe-phosphate mineral with low phosphate release potential, offers a promising solution for the simultaneous stabilization of cationic and anionic contaminants. This study evaluated the effectiveness of vivianite for concomitant immobilization of arsenite [As(III)], arsenate [As(V)], antimonite [Sb(III)], antimonate [Sb(V)], and Pb(II) in single- and mixed-metal(loid) solutions and contaminated soils. The adsorption of As(III), As(V), and Sb(III) onto vivianite followed the Langmuir isotherm model, indicating monolayer surface interaction. In mixed-metal(loid) solutions containing As or Sb with Pb, immobilization increased by 73% for As(III), 3271% for As(V), and 12% for Sb(III) compared to single-metal(loid) solutions. For Sb(V), immobilization increased from 0% in single-solution to 83% in mixed-metal(loid) solution. Phosphate released from vivianite reacted with Pb(II), resulting in Fe release. The liberated Fe subsequently reacted with As and Sb and enables their simultaneous immobilization. Application of vivianite decreased the concentrations of bioavailable As and Pb by 23% and 52%, respectively, in mixed-metal(loid) contaminated soil. In single-metal(loid) contaminated soil, bioavailable Sb and Pb were reduced by 16%, and 19%, respectively, compared to the control. Iron phosphate amendments often failed to achieve simultaneous stabilization of Pb and As because phosphate release promoted As remobilization. In contrast, vivianite enabled concomitant immobilization of both toxic oxyanions and cationic metals in soil during prolonged incubation by limiting phosphate release to levels insufficient to competitively displace As.