Environmental Geochemistry and Health最新文献

Cadmium (Cd) contamination in paddy soils poses significant risks to human health and food security, while traditional remediation methods may cause secondary pollution through external amendments. Nitrite oxidized Fe(II) to lepidocrocite and goethite, which immobilized Cd through adsorption and structural incorporation, effectively decreasing Cd mobility. Building on this mechanistic insight, a moisture regulation strategy was applied to enhance nitrite accumulation in paddy soil, and its role in Fe(II) oxidation for Cd immobilization was investigated. Metagenomic analysis identified nitrogen transformation pathways, showing that nitrite accumulation was limited by a higher abundance of ammonia-oxidizing bacteria (AOB, 19.2%) compared to nitrite-oxidizing bacteria (NOB, 11.7%), and predominance of nitrite consumption pathways. Maintaining 50% soil moisture selectively enhanced AOB activity while suppressing NOB, resulting in nitrite accumulation up to 9.56 mg/kg after 90 days incubation, reducing bioavailable Cd from 35 to 16% and increasing residual Cd from 7 to 48%. This study is original in integrating moisture regulation with microbial nitrogen cycling to enhance nitrite accumulation, thereby promoting Fe(II) oxidation and Cd immobilization. It provides a sustainable and chemical-free strategy for Cd management in paddy soils.

Metallic element (ME) contamination in urban road dust poses critical environmental and health challenges, particularly in Dhanbad, eastern India, representing one of the most intensively coal-mining-impacted urban regions in India, with over 112 active and abandoned mines, extensive overburden dumps, and widespread coal transportation corridors. This study systematically analyzed 44 composite road dust samples to quantify multiple MEs. Spatial interpolations, various geochemical indices, integrated Positive Matrix Factorization (PMF)- human health risk (HHR) framework based on Monte Carlo simulation was applied to comprehend the risk assessment. Excluding Al, all MEs exceeded their background value. Geochemical indices revealed moderate to very high contamination levels, particularly from Cd, As, and Cr. Spatial interpolation maps highlighted that coal mining zones, overburden dumps, and traffic-dense corridors, were the most polluted sites, prevailing in the central and NW-SE directions. Four major source factors of pollution were identified as mixed sources (F1), coal mining operations (F2), automotive and industrial emissions (F3), and lithogenic/overburden rock (F4). Multivariate statistical analyses further corroborated the findings of PMF. The integrated PMF-HHR framework, coupled with Monte Carlo simulation, revealed substantial non-carcinogenic (NCR) and carcinogenic risks (CR) for both adults and children. F2 followed by F3 were the predominant contributors to human health risks. Overall, the integrated PMF-HHR framework effectively linked source contributions to quantified health outcomes, providing a reliable tool for source-oriented risk management and mitigation in coal mining-affected urban environments.

As a region with a naturally high geochemical background, Southwestern China is subjected to intense anthropogenic perturbations from industrial, mining, and agricultural activities, posing significant ecological risks. To identify the characteristics and sources of heavy metal (HM) pollution in this complex environment, this study employed an integrated methodology including geochemical analysis, GIS-based mapping, Pearson correlation matrix (PCM), principal component analysis (PCA), geo-accumulation index (I_geo), potential ecological risk index (RI), ²¹⁰Pb dating, and dynamic leaching experiments in a pyrite mining-affected area. Results showed that Cd, Hg, Ni, Cu and Zn concentrations in soils and sediments exceeded Sichuan regional background values, with Cd being the most severe contaminant at up to 12.71- and 14.30-fold background levels, respectively. PCM and PCA revealed that Cd, Hg, Pb and As were primarily from anthropogenic sources. Spatially, Cd, Pb, and Hg were highly enriched in the eastern, central, and middle-lower river areas, while elevated levels of Ni, Cu, Zn and Cr were mainly found in the western area. I_geo and RI assessments identified considerable ecological risk, primarily from Cd and Hg. ²¹⁰Pb dating showed relatively low HM levels before 1989, a gradual increase from 1989 to 2009, followed by a fluctuating decline. Dynamic leaching tests demonstrated high Cd mobility in both soils and pyrite tailings, and its release was controlled by interfacial and internal diffusion as well as surface reactions. This integrated approach shows that effective pollution control in high-background regions requires coordinated management of both legacy contamination and ongoing anthropogenic emissions.

Microplastics (MPs) in freshwater environments are a significant ecological threat; however, their toxicological impact on endemic fish species is not well documented. This study aimed to assess the hazardous effects of polyethylene microplastics (PE-MPs) on endemic freshwater fish Tor putitora through a comprehensive assessment of integrated biomarkers. Fingerlings of T. putitora were exposed to PE-MPs at concentrations of 0, 0.1, 1, and 10 mg/L for 15 and 30 days. The findings revealed significant changes in hemato-biochemical, antioxidant, immunological, and neurotoxic biomarkers in fish exposed to PE-MPs, which varied with time and dosage. There was a notable (p < 0.05) reduction in red blood cells, hemoglobin, hematocrit, and platelet counts, whereas total leukocyte counts significantly (p < 0.05) increased in fish subjected to PE-MPs. Moreover, the levels of total protein, triglycerides, Fe²⁺, Na⁺, and Cl⁻ were reduced, whereas glucose, urea, creatinine, Ca²⁺, K⁺, and liver enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase) were increased in the treated groups. The increase in cortisol and thyroid stimulating hormone levels, coupled with a decline in tri-iodothyronine, thyroxine and insulin levels, suggests that PE-MPs caused stress in fish. Oxidative stress induced by PE-MPs was demonstrated by decreased catalase, superoxide dismutase, elevated malondialdehyde and glutathione activities in both gill and liver tissues. The immunological response in fish exposed to PE-MPs is enhanced through the induction of nitric oxide, respiratory burst, and lysozyme activity. Additionally, exposure to PE-MPs reduced acetylcholinesterase activity, underscoring the neurotoxic effects associated with PE-MPs. Correlation matrix and principal component analyses were employed to explore inter-biomarker relationships and to visualize treatment-specific clustering of responses. The findings indicate that particulate plastic pollution exerts harmful effects on fish, which may subsequently impact human health through the food chain. Future work should aim to enhance plastic waste control and strengthen pollution regulations in freshwater systems, particularly those supporting endemic fish species. Research should examine long-term effects of MPs and interactions with other pollutants like heavy metals and pharmaceuticals using omics tools and field studies.

In recent years, India has witnessed an alarming rise in air pollution levels, raising growing concerns among health and environmental experts. This study evaluates the inhalation cancer risk associated with fine particulate matter (PM_2.5) bound polycyclic aromatic hydrocarbons (PAHs) in two rapidly developing yet under-monitored regions of India. Ambient air samples were analyzed for 16 priority PAHs, and the carcinogenic risk was assessed using Incremental Lifetime Cancer Risk (ILCR) estimates through Monte Carlo simulations for both adults and children. The results indicated season and site-specific variations in PAH concentrations, with winter months showing higher cumulative BaP equivalent (BaPeq) levels. Adults consistently exhibited higher ILCR values than children, exceeding the acceptable risk threshold of 1 × 10^-6 in several scenarios.Global sensitivity analysis using the Sobol' method revealed that BaPeq concentration, exposure duration, and body weight were the most influential parameters affecting ILCR outcomes. Statistical validation using ANOVA and Tukey's post-hoc test confirmed significant seasonal and demographic variability. These findings emphasize the need for refined toxicity values and exposure inputs to improve human health risk assessments in India. This work combines field monitoring, probabilistic modelling, and uncertainty-based analysis to support evidence-driven air quality management, aligning with the goals of India's clean air strategies.

The Lingshui County lagoons represent Hainan's first marine special conservation area, yet little is known about the distribution and source characteristics of PAHs in their surface sediments. This study employed principal component analysis, PMF, and MERM-Q modeling to determine the distribution, sources, and potential ecological risks of PAHs in Lingshui Lagoon's surface sediments. The data indicate: (1) Spring PAH concentrations in the study area ranged from 18.12 to 111.30 ng/g (dry weight), with a mean concentration of 60.83 ng/g. Hexacyclic PAHs accounted for the highest proportion (52.43%), followed by tetracyclic PAHs (21.04%). (2) PMF model analysis revealed that PAHs in the lagoon primarily originate from fossil fuel and biomass combustion. (3) The PAH concentrations in the lagoon's surface sediments indicate moderate to low pollution levels, with relatively minimal potential ecological risk. These findings provide a reference for identifying PAH sources in Lingshui Lagoon's surface sediments and establish a scientific foundation for improving the lagoon's environmental quality.

The petrochemical industry is one of the main anthropogenic sources arsenic exposure. However, there is a lack of studies focusing on inorganic arsenic species and their impact on metabolites. Therefore, the purpose of this study was to investigate the exposure of arsenic species in the urine of residents living near a petrochemical industrial area in central Taiwan to determine whether it is associated with changes in metabolites. We recruited 81 children and 79 elderly residents living near a petrochemical complex in central Taiwan. Study subjects completed questionnaire survey and urine sample were collected to detect four arsenic species by HPLC-ICPMS and metabolites by GCxGC-TOFMS. Compared to the low exposure group, the children had significantly higher concentrations of all arsenic species, while the elderly had only significantly higher concentrations of inorganic arsenic in high exposure group. Specifically, children in the high-exposure area showed about 20-fold higher As³⁺ and tenfold higher As⁵⁺ concentrations, whereas elderly participants had 1.4-fold higher total arsenic levels. Moreover, high exposure groups performed significantly worse on various arsenic methylation indicators, especially in children. Further, we identified down-regulation of several inorganic arsenic-related methylation pathway metabolites and also found up-regulation of some metabolites of oxidative stress caused related to inorganic arsenic. We concluded that petrochemical industry may contribute to higher inorganic arsenic exposure related to worse arsenic detoxification ability and higher oxidative stress to residents nearby.

Groundwater arsenic contamination poses a significant health risk in coastal region of Bangladesh. However, existing studies have rarely applied advanced machine learning (ML) algorithms to predict arsenic concentrations using comprehensive water quality parameters (WQPs). Thus, this study evaluated multiple ML algorithms to predict arsenic concentrations based on measured WQPs including pH, water temperature (WT), electrical conductivity (EC), salinity (WS), dissolved oxygen (DO), total dissolved solids (TDS), water hardness (WH), total alkalinity (TA), chemical oxygen demand, chloride (CL), and biological oxygen demand. Descriptive statistics showed moderate variability and symmetrical distributions in WQPs, with arsenic level varying between 0.01 and 0.72 mg L^-1. Correlation analysis revealed positive associations between arsenic and all WQPs (WT, r = 0.29 to TDS, r = 0.63), except for a negative correlation with DO (r = - 0.41). Among the models, MLP exhibited better predictive performance, achieving R² increments of 24.75%, 13.06%, 16.92%, and 5.15%, and RMSE reductions of 34.88%, 26.32%, 30%, and 12.5%, compared against MLR, RFR, SVR, and XGB algorithms, in that order. According to the finding, model performance was ranked as MLP > XGB > RFR > SVR > MLR. Notably, input combination 6 (TDS, Cl, EC, WH, TA, WS) enabled the MLP model to explain over 78.70% of the total variance and contributed to 91.83% of the total prediction accuracy. This research may offer important insights for assessing arsenic contamination in groundwater across Bangladesh's southeastern coastal area.

Xylenol orange (XO) is a persistent anionic azo dye that resists conventional treatment. Cetyltrimethylammonium bromide (CTAB) and binding poly (vinylpyrrolidone) (PVP) were sequentially intercalated onto Na-montmorillonite (NaMt) to prepare a CTAB/PVP-modified Na-montmorillonite (CP-NaMt), and its adsorption toward XO was evaluated. The nanostructured adsorbent was characterized by chemical analysis, morphological, phase analysis, and point-of-zero-charge measurements. The characterization indicated successful organic intercalation accompanied by slight basal-spacing expansion, partial layer exfoliation and the development of a hierarchical micro-mesoporous structure. The Brunauer-Emmett-Teller specific surface area increased from 46.5 to 88.7 m²·g^-1. Batch tests identified pH = 5 as optimal, consistent with XO speciation and the positively charged surface of CP-NaMt. The adsorption process reached equilibrium rapidly, with a maximum capacity of 93.85 mg·g^-1 achieved within 40 min at 30 °C. Kinetics followed a pseudo-second-order model and intraparticle-diffusion analysis indicated multistage transport beginning with a film-diffusion regime. Equilibrium isotherms were better described by the Langmuir model. Thermodynamic analysis indicated a spontaneous, endothermic process with an entropy gain that facilitates desolvation and mass transport. Regeneration with ethanol maintained ≥ 87.4% removal over five cycles. Spectroscopic evidence and control experiments supported a mechanism dominated by electrostatic ion pairing at quaternary ammonium sites, further stabilized by hydrogen bonding and hydrophobic partitioning and π-π stacking within organic microdomains. This low-cost, regenerable clay platform shows potential for polishing dye-laden wastewater.