Environmental Geochemistry and Health最新文献

Polycyclic aromatic hydrocarbons (PAHs) are long-lasting organic pollutants which have toxic, mutagenic, and carcinogenic effects, making them of significant concern for both environmental and human health. This study determined the PAH levels in soils around the Rajiv Gandhi Thermal Power Plant, Khedar, Hisar (Haryana, India). Among 16 USEPA PAHs, 9 were detected. Descriptive statistics used in the study revealed that the concentration of Σ9PAHs in soils varied from 3354 to 44,648 μg kg^-1 with a mean of 7513.51 μg kg^-1. Diagnostic ratios (LMW/HMW = 0.61) revealed the prevalence of high-molecular-weight (HMW) PAHs, which validated a signature of combustion. The correlation patterns suggested a common pyrogenic source for most of the PAHs, with DahA suggesting another, sporadic one. PCA revealed two major source categories, coal-fired emissions and traffic contributions. Overall, the study reveals that 39 soil samples collected from the agricultural lands around the thermal power plant are dominated by high-molecular-weight PAHs. The lack of a big traffic route, as well as industrial activities in the area, indicates little impact from other sources. As a result, the PAH profile is primarily explained by pyrogenic sources, which can be attributed to the emissions from the thermal power plant. The ecological and carcinogenicity risks of PAHs in soils surrounding the RGTPP area were assessed by applying the risk quotient approach and the toxic equivalency approach. Some of the PAHs had risk levels above safe levels, and when they are combined, the ecological threat is very high. There is an imperative necessity for strategic management and remediation of the PAH polluted soil in the surroundings of RGTPP.

Radon (²²²Rn) is a globally recognized Class A carcinogen, and its accumulation in urban areas presents a critical challenge for public health and spatial planning. Effective environmental management requires accurate and scalable risk assessment, especially in geologically complex cities. The study presents the first systematic assessment of soil gas ²²²Rn in Yerevan, Armenia, combined with multi-depth profiling of natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K). This study addresses this issue by integrating a robust, data-driven Principal Component Regression (PCR) predictive framework to generate a hazard map of soil gas ²²²Rn activity across the urban environment of Yerevan, Armenia, and reveal key environmental and geological factors influencing soil gas ²²²Rn. The model integrates ²²²Rn activity measurements (ranging from 483.0 to 38,375.0 Bq/m³) with a comprehensive dataset of key predictor variables: multi-depth natural radionuclide activity concentrations, soil texture properties, and meteorological parameters, collected across a stratified sampling network. The resulting PCR prediction model with three component explains 33.6% of the variance in log-transformed ²²²Rn. Predictive power is primarily driven by PC1 (gamma-emitting radionuclide abundance and fine-grained soil texture) and PC2 (measurement depth and coarse-textured soils). Leave-One-Out Cross-Validation (LOOCV) confirmed structural model stability (cross-validated R² = 0.115 on log scale), although extreme values were conservatively underestimated. The resulting hazard map delineates radon-prone zones primarily in central-eastern and southern districts associated with permeable sedimentary formations. Despite moderate explanatory power, the PCR framework provides an interpretable and statistically robust basis for preliminary radon hazard zoning in geologically heterogeneous urban areas.

Oil extraction activities generate both organic and metal pollution, however, trace elements in oilfield areas have received less attention in terms of investigation and risk assessment. This study investigated the accumulation levels of eight trace elements (Cd, Mn, Ni, Cu, Pb, Zn, Cr, and Hg) in soils, plants, and animals from three sampling lines using ICP-MS. Potential ecological risks of these elements were assessed based on the local geochemical background of soils and the hazardous concentration for 5% species (HC₅) derived from the Species Sensitivity Distribution Curves of plant and animals. Biomagnification of these elements was characterized with the Biomagnification Factor (BMF). The results indicated potential soil contamination with Pb (19.8 ± 5.2 mg/kg) and Hg (0.023 ± 0.012 mg/kg), exceeding local environmental background values by 1.02 and 1.04 times, respectively. High accumulation of Mn, Zn, and Cu was observed in plants and animals, with concentrations ranging from 21.2 to 153, 20.4-335, and 12.7-143 mg/kg, respectively. Higher elemental concentrations were observed in Goosegrass (Mn: 93.5 ± 15.3 mg/kg, Zn: 32.2 ± 7.9 mg/kg, Cu: 9.1 ± 1.0 mg/kg) and grubs (Mn: 152 ± 38.1 mg/kg, Zn: 202 ± 45.3 mg/kg, Cu: 118 ± 8.1 mg/kg), demonstrating a stronger capacity for accumulating these elements. Mn, Cu, and Zn posed relatively high risks to the investigated organisms especially for insects, with Hazard Quotient (HQ) value high to 12,059, 25,191 and 9017, respectively. Biomagnification was evident for Zn, Hg, Cd, and Cu through the food chain transfer, with BMF high to 6.1, 26.1, 15.2, and 12.1, respectively. These findings highlight that less-regulated trace elements like Mn, Cu, and Zn, often perceived as less hazardous, can present ecological risks in oilfields via high bioaccumulation and trophic transfer, warranting greater attention in oilfield management.

Arsenic (As), particularly in its bioavailable species of inorganic As(Ⅲ) known for its significant toxicity and mobility, is a carcinogenic risk to humans. Serving as an innovative analytical tool, the diffusive gradients in thin films (DGT) technique facilitates on-site detection of bioavailable metals. However, the options of DGT binding gels tailored for As(Ⅲ) detection remain elusive. This study undertook the modification of tetraethyl orthosilicate with a 3-mercaptopropyl-trimethoxysilane to synthesize cost-effective nanomaterials endowed with the capacity for selective adsorption of As(Ⅲ) through copolymerization and atmospheric pressure drying. The synthesized materials were systematically characterized using X-ray diffraction, scanning electron microscopy, and C/H/N/S elemental analysis, revealing a specific surface area of 472.39 m²/g, a particle size of 12.7 nm, and a loading capacity of 3.115 mmol/g. The DGT combined with gel prepared from this material has a specific affinity for As(III) without adsorbing As(V).Its adsorption efficiency for As(III) may reach 84.5% within the first hour. This DGT technique has a linear detection range of 0.5-15 mg/L (R² = 0.99995), an elution recovery of 85.1%-102.7% (RSD < 10%, n = 3), and a maximum adsorption capacity of 301.7 μg/cm², meeting requirements for long-term environmental monitoring. The experiment studied the effects of interfering factors, including pH values ranging from 3-9, ionic strength of 10-500 mmol/L NaNO₃, Fe²⁺ 0-5.0 mg/L, Mn²⁺ 0-1.0 mg/L, As(V) 0-5.0 mg/L, dissolved organic carbon 0-20.0 mg/L, SO₄²⁻ 0.55-1.10 g/L, and PO₄³⁻ 5.0-10.0 mg/L. The device maintained a stable treatment performance under all these conditions. When the DGT device was deployed in spiked river water, estuarine water, and seawater, a comparison of its adsorption performance with existing methods showed that the device had a comparable adsorption performance and demonstrated excellent long-term stability in practical water environment applications.

Excavation and retreatment of landfilled chelated incineration fly ash (CIFA) is an important pathway to recovering landfill capacity and improving waste management, but its potential risks remain unclear. This study investigates the secondary release behaviors of chloride and heavy metals during water washing of landfilled CIFA. Under the optimal water washing conditions-liquid-solid ratio of 8.3:1, 50 min, and 63 °C-soluble chlorides were effectively leached, yielding a chloride removal of 86.95%; the residual soluble Cl content dropped below 1 wt%, meeting the requirement for direct high-temperature thermal treatment. Water washing promoted the release of heavy metals into the aqueous phase predominantly as hydroxo-complex anions, while the remaining metals in the solid occurred mainly in the oxidizable and residual fractions. The risk assessment indices for the Washed CIFA (WCIFA) indicated that the potential risk of Pb escalated from "low" to "medium", necessitating continued attention during subsequent thermal treatment. Nevertheless, the synthetic toxicity index and hazard index for heavy metals suggested that the overall environmental risk of the WCIFA was low. Overall, water washing not only efficiently extracts soluble chlorides from CIFA but also mitigates the overall risk of heavy metals, thereby validating the process as an effective pretreatment step for its subsequent management.

Heavy metal(loid)s (HMs) contamination in aquatic sediments poses critical threats to ecosystems and public health, driving intensive research into in situ remediation technologies that offer minimal ecological disturbance and cost-effectiveness. This review systematically investigates mainstream and emerging techniques for HMs-contaminated sediment remediation, encompassing established methods such as physical capping, chemical stabilization, phytoremediation, and microbial remediation, alongside innovative approaches including nanoremediation and electrokinetic treatment. Physical capping controls pollutant release via isolation and adsorption, though long-term efficacy can be compromised by sediment consolidation and gas ebullition. Chemical stabilization employs amendments such as biochar and minerals to reduce HMs bioavailability through adsorption, precipitation, and redox mechanisms. Phytoremediation and microbial remediation represent environmentally sustainable approaches leveraging natural metabolic processes for HMs extraction, stabilization, or transformation. Nanoremediation achieves superior passivation using highly reactive nanomaterials like nanoscale zero-valent iron and nano-hydroxyapatite, while electrokinetic remediation applies electric fields to facilitate HMs migration, proving particularly effective in low-permeability sediments. Significantly, technology integration generates substantial synergistic effects. Coupling bioleaching with Fenton-like reactions enhanced Cd removal efficiency from approximately 90 to 99.5%, whereas nano-silica modification of cement-based stabilization improved Pb immobilization from 88.7 to 97.6%. These advances underscore the superior precision and efficiency of coupled technologies for complex pollution scenarios. This comprehensive review elucidates fundamental principles, recent progress, application potential, and inherent limitations of current remediation strategies, while identifying critical future development trends essential for advancing sustainable and effective sediment restoration practices in contaminated aquatic environments.

The environmentally friendly biopolymers have been widely utilized in geotechnical engineering in recent years to enhance soil structure and mechanical performance. However, their potential in remediating heavy metal-contaminated soils remains insufficiently explored and recognized. This study proposed three biopolymers, xanthan gum (XaG), guar gum (GuG), and gellan gum (GeG), as green soil amendments to evaluate their immobilization efficacy for heavy metal (Cu, Pb, Cd) contaminated soils. To assess the long-term stability and dosage effects, soil samples were treated with biopolymer concentrations of 0.25%, 0.5%, and 1%, and tested after 1, 28, and 90 d of curing. Then, TCLP leaching, DTPA extraction and BCR sequential extraction were conducted to assess the leachability, bioavailability, and speciation of heavy metals in soil. Under optimal conditions, the toxic leaching risk of Cu, Pb, and Cd were reduced by 29.55-32.73%, 14.09-15.26%, and 6.23-11.47%, respectively, while their bioavailability values were decreased by 12.8-31.58%, 5.71-12.01%, and 14.22-16.57%. XaG exhibited continuously enhanced immobilization capacity under high content and long-term curing, whereas the immobilization effects of GuG and GeG were primarily observed at the medium-term curing stage (28d). BCR results further indicated that biopolymers promoted the transformation of heavy metals from acid-soluble fractions to stable fractions such as reducible or residual fractions. The mechanisms underlying heavy metal immobilization by biopolymers mainly involve functional group complexation, electrostatic attraction, and physical entrapment by the gel network. The findings highlight the application potential of biopolymers in the immobilization of heavy metal-contaminated soils.

Rare earth elements (REEs) are widely used as tracers in many fields of geoscience research to study material sources and evolutionary processes. Therefore, this study collected a total of 85 groundwater samples from the Huainan Coalfield, It systematically investigated the geochemical characteristics of REEs in different aquifers. The research indicate that the main hydrochemical types of groundwater are Cl-Na and Cl-HCO₃-Na facies. The average ∑REE concentrations in the roof sandstone water of the No. 9 coal seam, Ordovician limestone water, Taihui limestone water, and goaf water are 0.4576 μg/L, 0.2170 μg/L, 0.2235 μg/L, and 0.7230 μg/L, respectively, all lower than the world river average of 0.7450 μg/L. With the exception of goaf water, all other aquifers show ∑HREE > ∑LREE. The REE partitioning pattern diagram reveals a certain degree of negative Ce anomaly and positive Eu anomaly in the groundwater of the study area. Correlations exist between REEs and conventional components in the various aquifers, leading to the inference that the geochemical characteristics of REEs are collectively influenced by carbonate complexation, adsorption-desorption, water-rock interactions, and redox reactions. The ∑REE-δEu diagram shows that the Ordovician limestone water has low ∑REE and δEu values, while the other three aquifers exhibit elevated ∑REE and δEu, potentially related to water-rock interactions.The Absolute Principal Component Score-Multiple Linear Regression(APCS-MLR) model identified four sources: Source 1 represents the mineral factor, contributing 17.16%. Source 2 represents the anthropogenic factor, contributing 33.07%. Source 3 represents the weathering factor, contributing 48.05%. Source 4 represents an unknown source, contributing 1.72%, which is speculated to potentially be influenced by shallow groundwater recharge.

Soil contamination by metals poses a significant threat to food safety and human health, particularly through the consumption of vegetables cultivated in mining-impacted areas. In Colombia, gold mining and horticultural activities frequently coexist; however, information on the uptake of mining-associated metals by edible crops and the resulting health risks remains limited. This study investigated the accumulation of mercury (Hg), lead (Pb), and arsenic (As) in sweet pepper (Capsicum annuum) cultivated in soils affected by gold mining and evaluated the potential human health risks. A single-factor experimental design was employed using soils collected at three distances from active mining sites (S1: 0.6 km, S2: 3 km, and S3: 20 km). Plants were grown under screen-house conditions for 143 days, during which morphometric, physiological, and chemical analyses were performed. Soil concentrations of metals decreased with increasing distance from mining activity: S1 (Hg: 22.13, Pb: 1997.02, As: 37.52 mg kg^-1), S2 (Hg: 5.38, Pb: 186.03, As: 15.70 mg kg^-1), and S3 (Hg: 2.05, Pb: 57.19, As: 7.90 mg kg^-1), with generally low bioavailability (Hg and As < 1%; Pb: 2-11%). Metal accumulation occurred predominantly in roots, with limited translocation to aerial and edible tissues. Bioconcentration factor (BCF) and translocation factor (TF) were consistently below unity, indicating limited uptake and internal transfer of Hg, Pb, and As. Human health risk assessment based on Codex Alimentarius provisional tolerable weekly intake (PTWI), margin of exposure (MOE), total hazard quotient (THQ), and incremental lifetime cancer risk (ILCR) indicated low non-carcinogenic risk and negligible carcinogenic risk at distances of 3 and 20 km. Although Hg concentrations exceeded the limits established by the Chinese National Food Safety Standard (GB 2762-2022), which sets a threshold of 0.1 mg kg^-1, the overall results suggest no immediate health risk from consumption. Nevertheless, considering the persistence and bioaccumulative nature of these elements, long-term exposure risks cannot be excluded, highlighting the need for continuous monitoring of agricultural systems in mining-influenced regions.

Nitrate and Fluoride are both useful and deadly at varying concentrations, hence the need for continuous monitoring. The cancer risk associated with nitrate is yet to be investigated in Nigerian waters. This study assessed the human health risks associated with groundwater usage by adults, teenagers, children, and infants across Lagos, Ogun, Oyo, Osun, Ekiti, Ondo, Imo, Ebonyi, Delta, and the Federal Capital Territory through oral and dermal exposures. A total of 623 groundwater samples (537 hand-dug wells and 86 boreholes) were analyzed for nitrate and fluoride using standard procedures. Fluoride concentrations ranged from 1.25 ± 0.07 to 8.47 ± 3.19 mg/L, with most samples exceeding national and international water quality guidelines of 1.5 mg/L. Nitrate levels were generally within safe limits (2.50 ± 0.14-13.37 ± 0.48 mg/L), except in Delta communities (Kurutie, Kunukunuma, Okerenkoko), where values exceeded 50 mg/L, suggesting contamination from anthropogenic activities. Risk assessment showed oral ingestion as the primary exposure pathway while dermal risk was negligible. The Hazard Quotient for fluoride via ingestion (HQ > 1) indicated significant non-cancer risks for all age groups (0.846-8.997) while for nitrate it was negligible in all communities except for Kurutie (1.827-2.690), Kunukunuma (1.645-2.423), and Okerenkoko (1.639-2.413). The Mean Cancer Risk (MCR) values for nitrate exceeded the USEPA threshold (1 × 10^-6) across all age groups, with Delta State hotspots reaching 10^-3. Findings demonstrate that groundwater in the region poses both non-cancer and cancer risks, underscoring the urgent need for intervention strategies such as defluoridation, denitrification, and safe alternative provision.