Search Results (264)

Compression of clayey sediments not only causes land subsidence but also results in geogenic high fluoride groundwater. The distribution characteristics and enrichment mechanisms of fluoride in alluvial−lacustrine facies clayey sediments in the land subsidence area of Cangzhou Plain, China, were investigated using sample collection, mineralogical research, and hydrogeochemical and isotopic analysis. The results show that F⁻ concentration of groundwater samples ranged from 0.31 to 5.54 mg/L in aquifers. The total fluoride content of clayey sediments ranged from 440 to 792 mg/kg and porewater F⁻ concentration ranged from 0.77 to 4.18 mg/L. Clay minerals containing fine particles, such as muscovite, facilitate the enrichment of fluoride in clayey sediments, resulting in higher total fluoride levels than those in sandy sediments. The clay porewater F⁻ predominantly originated from the dissolution of water-soluble F and the desorption of exchangeable F from sediments. The F⁻ concentration in porewater was further influenced by ionic interactions such as cation exchange. The stable sedimentary environment and intense compression promoted the dissolution of F–bearing minerals and the desorption of adsorbed F in deep clayey sediments. The similar composition feature of δ²H−δ¹⁸O in deep groundwater and clay porewater samples suggests a significant mixing effect. These findings highlight the joint effects of hydrogeochemical and mineralogical processes on F behavior in clayey sediments. Full article

This study develops an integrated framework for groundwater pollution source identification by coupling Principal Component Analysis (PCA), Positive Matrix Factorization (PMF), and the Mantel test, with the Qujiang River Basin as a case study. The framework enables a full-process assessment, encompassing qualitative identification, quantitative apportionment, and spatial validation of pollution drivers. Results indicate that groundwater chemistry is primarily influenced by three categories of sources: natural rock weathering, agricultural and domestic activities, and industrial wastewater discharge. Anthropogenic sources account for 73.7% of the total contribution, with mixed agricultural and domestic inputs dominating (38.5%), followed by industrial effluents (35.2%), while natural weathering contributes 26.3%. Mantel test analysis further shows that agricultural and domestic pollution correlates strongly with intensive farmland distribution in the midstream area, natural sources correspond to carbonate outcrops and higher elevations in the upstream, and industrial contributions cluster in downstream industrial zones. By integrating PCA, PMF, and Mantel analysis, this study offers a robust and transferable framework that improves both the accuracy and spatial interpretability of groundwater pollution source identification. The proposed approach provides scientific support for regionalized groundwater pollution prevention and control under complex hydrogeological settings. Full article

The Three Gorges Reservoir, serving as a crucial ecological barrier for the middle-lower Yangtze River basin, faces substantial threats to watershed ecosystems from sediment-associated heavy metal, threatening aquatic ecosystems and human health via bioaccumulation. Leveraging the legislative framework of the Yangtze River Protection Law, this study analyzed sediment cores (0–65 cm) collected from 12 representative sites in the Three Gorges Reservoir using 2020 Air–Space–Ground integrated monitoring data from the Changjiang Water Resources Commission. Concentrations of nine heavy metals (Cd, Cu, Pb, Fe, Mn, Cr, As, Hg, and Zn) were quantified to characterize spatial and vertical distribution patterns. Source apportionment was conducted through correlation analysis and principal component analysis (PCA). Contamination severity and ecological risks were assessed via geo-accumulation index (I_geo), potential ecological risk index (RI), and acute toxicity metrics. The findings indicated substantial spatial heterogeneity in sediment heavy-metal concentrations, with the coefficients of variation (CV) for Hg and Cd reaching 214.46% and 116.76%, respectively. Cu and Pb showed surface enrichment, while Cd exhibited distinct vertical accumulation. Source apportionment indicated geogenic dominance for most metals, with anthropogenic contributions specifically linked to Cd and Hg enrichment. Among the metals assessed, Cd emerged as the primary ecological risk driver, with localized strong risk levels (E_i > 320), particularly at FP and SS sites. These findings establish a scientific foundation for precision pollution control and ecological restoration strategies targeting reservoir sediments. Full article

This study examines the impact of physicochemical and geological factors on radon concentrations in groundwater throughout the Mexican Altiplano. Geological diversity, uranium deposits, seismic zones, and geothermal areas with high heat flow are all potential factors contributing to the presence of radon in groundwater. To move beyond local-scale assessments, this research employs spatial prediction methodologies that incorporate geological and geochemical variables recognized for their role in radon transport and geogenic potential. Certain properties of radon enable it to serve as an ideal tracer, viz., short half-life, inertness, and higher incidence in groundwater than surface water. Twenty-five variables were analyzed in samples from 135 water wells. Geostatistical techniques, including inverse distance weighted interpolation and kriging, were used in conjunction with multivariate statistical analyses. Salinity and geothermal heat flow are key indicators for determining groundwater origin, revealing a dynamic interplay between geothermal activity and hydrogeochemical evolution, where high temperatures do not necessarily correlate with increased solute concentrations. The occurrence of toxic trace elements such as Cd, Cr, and Pb is primarily governed by lithogenic sources and proximity to mineralized zones. Radon levels in groundwater are mainly influenced by geological and structural features, notably rhyolitic formations and deep hydrothermal systems. These findings underscore the importance of site-specific groundwater examination, combined with spatiotemporal models, to account for uranium–radium dynamics and flow paths, thereby enhancing radiological risk assessment. Full article

Natural geogenic effects lead to alterations in soil heavy metal concentrations. This study assesses the presence of elevated trace-element concentrations in the Oued Irriri watershed in southeastern Morocco. ASTER satellite imagery, geochemical, and aeromagnetic data are combined to determine the origin of these anomalies. Processing of ASTER images delineated alteration zones coinciding with areas of high heavy metal anomalies by detecting hydrothermal alteration minerals, including muscovite, montmorillonite, illite, hematite, jarosite, chlorite, and epidote. Principal Component Analysis (PCA) of geochemical data distribution in soils enabled the characterization of variations in trace-element concentrations, the extraction of geochemical anomalies, and the identification of potential sources of contamination. Comparing satellite image processing results with geochemical analyses facilitated the production of a geogenic enrichment map. The study results indicate high enrichment levels of zinc, Molybdenum, and bismuth in the western basin, of purely lithological origin. Hydrothermal alteration surfaces intersect geochemical anomaly zones in the north and northeast, primarily showing the impact of fault rooting on the surface deposition of Cu, Ba, Hg, and Pb-rich deposits. This study developed a geogenic enrichment map indicating naturally affected areas, identifying potential risks to eco-environmental systems, and better preventing the effects of geogenic enrichment. Full article

Monitoring the concentration of heavy metals in urban soils is of a paramount importance for several reasons. These inorganic pollutants can pose a significant health risk to living organisms, as they are toxic even at low concentrations and can be present in the soil for a long period of time. This study assesses the spatial distribution, concentration levels, and potential anthropogenic and natural sources of eight typical heavy metals (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) occurring in urban surface soils across Debrecen, Hungary. A total of 295 topsoil samples were collected; heavy metal concentrations were determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry. The results were interpreted using descriptive statistics, correlation analysis, hierarchical clustering, factor analysis, ordinary kriging interpolation, and spatial-discriminant analysis. The dual origin of the metal contaminants was revealed: As, Co, Pb, and Zn showed strong anthropogenic signatures associated with traffic, urban waste, and construction materials, whereas Cr and Ni were associated with natural geogenic sources. Cd reflected both lithogenic and point-source urban pollution. The current evaluation incorporated Hungarian and Dutch regulatory benchmarks to identify exceedances of environmental quality thresholds. It was found that only Cd and Cr exceeded the Hungarian target values, on average. Linear discriminant analysis based on pollution maps highlighted contamination hotspots around traffic corridors and newly industrialized zones. The importance of high-resolution soil monitoring in the rapidly urbanizing city is highlighted. Given its anticipated industrial and transportation developments, accumulations of heavy metals are probably going to be further exacerbated; therefore, the results provide a critical baseline for future environmental assessments and long-term monitoring. Full article

This study systematically investigates soil and stream sediment along the 165 km Ibar River to examine the origin and transfer of pollutants. The research focuses on the environmental impact of long-term mining and irregular waste management, as well as natural enrichment related to weathering processes. A comprehensive sampling campaign was conducted, collecting 70 samples from 14 locations. At each location, samples of river sediment, floodplain soil (0–5 cm and 20–30 cm depths), and river terrace soil (same depths) were collected. The contents of 21 elements (Ag, Al, As, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Sr, V, and Zn) were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES). Analysis of Variance (ANOVA) was performed to identify statistically significant differences in element contents between defined zones, sampled materials (river sediments, floodplain soils, and river terrace soils), and sampled soil horizons (topsoil, 0–5 cm, and subsoil, 20–30 cm). Multivariate analysis, including correlation coefficient, cluster analysis, and principal component analysis, revealed two distinct groups of elements with highly significant correlation coefficients (r > 0.7). The first group, comprising Ag, As, Cd, Cu, Mn, and Zn, indicates anthropogenic enrichment, likely resulting from mining and smelting activities in the middle flow of the Ibar River (The Mining and Metallurgical Complex Trepča). The second group, consisting of Cr, Mg, and Ni, suggests enrichment related to the weathering of elements from the ophiolite zone in the lower Ibar River. The study found high enrichment ratios of toxic elements like arsenic, cadmium, lead, and zinc, particularly in stream sediments and floodplains. Notably, arsenic contents exceeded European averages by up to 57 times in stream sediments, posing a significant environmental concern due to its high content. Full article

This study comprehensively evaluates heavy metal (HM) contamination and associated health risks in 31 groundwater samples from Wadi Al-Hamd, northwest Saudi Arabia. Cd, Pb, Zn, As, Cr, Cu, Ba, and Ni showed variable concentrations, some elements approaching WHO guideline values in localized samples. The analyzed HMs showed variable concentrations, with As reaching 5.02 µg/L (50% of WHO guideline) in sample M27. The heavy metal pollution index (HPI) ranged from 0.15 (M29) to 10.07 (M27), with values below 15 indicating low pollution overall, while the metal index (MI) ranged from 0.022 (M29) to 0.621 (M27), all below the threshold of 1 for safe water, indicating geogenic enrichment, particularly in arsenic and nickel. Principal component analysis identified three PCs explaining 73.58% of total variance, with PC1 (35.50%) dominated by Zn-Cu-Ni (geogenic weathering) and PC2 (23.62%) by As-Cd (redox-driven dissolution). Health risk assessment via chronic daily intake (CDI), hazard quotient (HQ), and hazard index (HI) models confirmed negligible non-carcinogenic risks (HI < 1) for both adults and children, though children exhibited 1.5–2 times higher exposure. The highest HQ values were observed for As (HQoral-child: 0.365 in M27), approaching but not exceeding safety thresholds. Dermal exposure contributed minimally (<1% of total risk). The average lifetime carcinogenic risk (LCR) due to exposure to arsenic through drinking water aligns with the US EPA’s acceptable risk range of 1 × 10⁻⁶ to 1 × 10⁻⁴ (average 1.18 × 10⁻⁵ for adults, 2.06 × 10⁻⁵ for children). These findings align with regional studies, but highlight localized As high values for few samples. The study underscores the dominance of natural weathering in HM release and provides a framework for targeted groundwater management in arid regions. Full article

Geogenic contamination of groundwater presents a substantial threat to the enduring production and sustainability of irrigated fruit orchards, especially in arid and semi-arid regions where over 60% of horticultural irrigation depends on groundwater sources. Groundwater quality is increasingly threatened by geogenic contamination, presenting a critical global issue. Geogenic contaminants, such as fluoride and arsenic, combined with agricultural practices and inadequate wastewater treatment, pose a significant threat to groundwater. Concentrations of elements including arsenic, fluoride, boron, iron, and sodium often exceed acceptable thresholds. For instance, arsenic (As) levels up to 0.5 ppm have been reported in parts of South Asia, far exceeding the WHO guidelines limit of 0.01 mg/L. Boron concentrations above 2.0 ppm and fluoride concentrations exceeding 1.5 ppm are prevalent in impacted aquifers. Pollution consequences are far reaching, impacting agricultural ecosystems and human health as polluted water infiltrates the food chain via irrigation. These challenges are compounded by climate change and water scarcity, which further strain water sources, including those used in agriculture. Addressing groundwater contamination requires a multi-faceted approach. Strategies include developing crops that can tolerate toxicants, improving irrigation techniques, and employing advanced wastewater treatment technologies. This study solidifies current knowledge concerning the uptake processes and physiological effects of various pollutants in fruit crops. This review emphasizes the synergistic toxicity of many pollutants, identifies gaps in knowledge in species-specific tolerance, and emphasizes the dearth of comprehensive mitigating frameworks. Potential solutions, such as salt-tolerant rootstocks, gypsum amendments, and alternative irrigation timing, are examined to enhance resilient orchard systems in geogenically challenged areas. Full article

Groundwater quality in arid and semi-arid regions of Morocco is under increasing pressure due to both anthropogenic influences and climatic variability. This study investigates the physicochemical and heavy metal characteristics of groundwater across four Moroccan regions (Tangier-Tetouan-Al Hoceima, Oriental, Souss-Massa, and Marrakech-Safi) known for being argan tree habitats. Thirteen groundwater samples were analyzed for twenty-five parameters, including major ions, nutrients, and trace metals. Elevated levels of ammonium, turbidity, electrical conductivity, and dissolved oxygen were observed in multiple samples, surpassing Moroccan water quality standards and indicating significant quality deterioration. Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) detected arsenic concentrations exceeding permissible limits in sample AW11 alongside widespread lead contamination in most samples except AW5 and AW9. Spatial patterns of contamination were characterized using Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), K-means clustering, and GIS-based Inverse Distance Weighted (IDW) interpolation. These multivariate approaches revealed marked spatial heterogeneity and highlighted the dual influence of geogenic processes and anthropogenic activities on groundwater quality. To assess consumption suitability, a Water Quality Index (WQI) and Human Health Risk Assessment were applied. As a result, 31% of samples were rated “Fair” and 69% as “Good”, but with notable non-carcinogenic risks, particularly to children, attributable to nitrate, lead, and arsenic. The findings underscore the urgent need for systematic groundwater monitoring and management strategies to safeguard water resources in Morocco’s vulnerable dryland ecosystems, particularly in regions where groundwater sustains vital socio-ecological species such as argan forests. Full article

This study evaluates the potential health risks posed by geogenic arsenic in environments suitable for leisure activities, such as walking, bathing, and playing, for adults and children alike, as well as in neighbouring agricultural areas. The study includes an analysis of environmental characteristics and the main stream originating in the adjacent mining area, with water and sediment samples taken. The study area is representative of other areas in the vicinity of the Mar Menor Lagoon, which is one of the largest and most biodiverse coastal lagoons in the Mediterranean Sea. The general characteristics of the soil and water were determined for this study, as was the concentration of As in the soil and water samples. A granulometric separation was carried out into four different fractions (<2 mm, <250 µm, <100 µm, and <65 µm). The mineralogical composition, total As content, and bioaccessible As content are analysed in each of these fractions. This provides data with which to calculate the danger of arsenic (As) to human health by ingestion and to contribute to As bioaccessibility studies and the role played by the mineralogical composition and particle size of soil ingestion. The conclusions rule out residential use of this environment, although they allow for eventual tourist use and traditional agricultural use of the surrounding soils. Full article

This study investigates the heavy metal contamination in urban and peri-urban soils of Thessaloniki, Greece, over a two-year period (2023–2024). A total of 208 composite soil samples were systematically collected from 52 sites representing diverse land uses, including high-traffic roadsides, industrial zones, residential neighborhoods, parks, and mixed-use areas, with sampling conducted both after the wet (winter) and dry (summer) seasons. Soil physicochemical properties (pH, electrical conductivity, texture, organic matter, and calcium carbonate content) were analyzed alongside the concentrations of heavy metals such as Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn. A pollution assessment employed the Geoaccumulation Index (I_geo), Contamination Factor (Cf), Pollution Load Index (PLI), and Potential Ecological Risk Index (RI), revealing variable contamination levels across the city, with certain hotspots exhibiting a considerable to very high ecological risk. Multivariate statistical analyses (PCA and HCA) identified distinct anthropogenic and geogenic sources of heavy metals. Health risk assessments, based on USEPA models, evaluated non-carcinogenic and carcinogenic risks for both adults and children via ingestion and dermal contact pathways. The results indicate that while most sites present low to moderate health risks, specific locations, particularly near major transport and industrial areas, pose elevated risks, especially for children. The findings underscore the need for targeted monitoring and remediation strategies to mitigate the ecological and human health risks associated with urban soil pollution in Thessaloniki. Full article

Artisanal and small-scale gold mining (ASGM) poses significant environmental challenges globally, particularly due to mercury (Hg) use. As an example, in Ecuador, Hg use still persists, despite its official ban in 2015. This study investigated the geogenic and anthropogenic contributions of potentially toxic elements (PTEs) in the Ponce Enriquez Mining District (PEMD), a region characterized by hydrothermally altered basaltic bedrock and Au-mineralized quartz veins. To assess local baseline values and identify PTE-bearing minerals, a comprehensive geochemical, mineralogical, and petrographic analysis was conducted on bedrock and mineralized veins. These findings reveal distinct origins for the studied PTEs, which include Hg, As, Cu, Ni, Cr, Co, Sb, Zn, and V. Specifically, Hg concentrations in stream sediments downstream (up to 50 ppm) far exceed natural bedrock levels (0.03–0.707 ppm), unequivocally indicating significant anthropogenic input from gold amalgamation. Furthermore, copper shows elevated concentration primarily linked to gold extraction. Conversely, other elements like As, Ni, Cr, Co, Sb, Zn, and V are primarily exhibited to be naturally abundant in basalts due to the presence of primary mafic minerals and to hydrothermal alterations, with elevated concentrations particularly seen in sulfides like pyrite and arsenopyrite. To distinguish natural geochemical anomalies from mining-related contamination, especially in volcanic terrains, this study utilizes Upper Continental Crust (UCC) normalization and local bedrock baselines. This multi-faceted approach effectively helped to differentiate basalt subgroups and assess natural concentrations, thereby avoiding misinterpretations of naturally elevated element concentrations as mining-related pollution. Crucially, this work establishes a robust local geochemical baseline for the PEMD area, providing a critical framework for accurate environmental risk assessments and sustainable mineral resource management, and informing national environmental quality standards and remediation efforts in Ecuador. It underscores the necessity of evaluating local geology, including inherent mineralization, when defining environmental baselines and understanding the fate of PTEs in mining-impacted environments. Full article

Microelement deficiencies, often termed “hidden hunger”, represent a significant global health challenge. Optimal human health relies on adequate dietary intake of essential microelements, including selenium (Se), zinc (Zn), copper (Cu), boron (B), manganese (Mn), molybdenum (Mo), iron (Fe), nickel (Ni), and chlorine (Cl). In recent years, there has been a growing focus on vitality and longevity, which are closely associated with the sufficient intake of essential microelements. This review focuses on these nine elements, whose bioavailability in the food chain is critically determined by their geochemical behavior in soils. There is a necessity for an understanding of the sources, soil–plant transfer, and plant uptake mechanisms of these microelements, with particular emphasis on the influence of key soil properties, including pH, redox potential, organic matter content, and mineral composition. There is a dual challenge of microelement deficiencies in agricultural soils, leading to inadequate crop accumulation, and the potential for localized toxicities arising from anthropogenic inputs or geogenic enrichment. A promising solution to microelement deficiencies in crops is biofortification, which enhances nutrient content in food by improving soil and plant uptake. This strategy includes agronomic methods (e.g., fertilization, soil amendments) and genetic approaches (e.g., marker-assisted selection, genetic engineering) to boost microelement density in edible tissues. Moreover, emphasizing the need for advanced predictive modeling techniques, such as ensemble learning-based digital soil mapping, enhances regional soil microelement management. Integrating machine learning with digital covariates improves spatial prediction accuracy, optimizes soil fertility management, and supports sustainable agriculture. Given the rising global population and the consequent pressures on agricultural production, a comprehensive understanding of microelement dynamics in the soil–plant system is essential for developing sustainable strategies to mitigate deficiencies and ensure food and nutritional security. This review specifically focuses on the bioavailability of these nine essential microelements (Se, Zn, Cu, B, Mn, Mo, Fe, Ni, and Cl), examining the soil–plant transfer mechanisms and their ultimate implications for human health within the soil–plant–human system. The selection of these nine microelements for this review is based on their recognized dual importance: they are not only essential for various plant metabolic functions, but also play a critical role in human nutrition, with widespread deficiencies reported globally in diverse populations and agricultural systems. While other elements, such as cobalt (Co) and iodine (I), are vital for health, Co is primarily required by nitrogen-fixing microorganisms rather than directly by all plants, and the main pathway for iodine intake is often marine-based rather than soil-to-crop. Full article

This study investigates the influence of environmental variables on the elemental composition of Hypnum cupressiforme Hedw. mosses in Georgia and the Republic of Moldova, within moss biomonitoring studies aimed at analyzing atmospheric deposition patterns. Moss samples of Hypnum cupressiforme, characterized by a cosmopolitan distribution and a wide range of habitats, were collected from diverse geographical and climatic zones and analyzed for Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, and Zn. Statistical methods (Spearman correlations, PCA, Kruskal–Wallis tests) were applied to evaluate interactions between elemental concentrations and factors such as topography, climate, land cover, etc. Results revealed strong correlations among lithogenic elements (Al, Co, Cr, Fe, Ni, and V), indicating natural weathering sources, while Cu exhibited potential anthropogenic origins in the Republic of Moldova. Elevated Cd and Pb levels in Georgian high-altitude regions were linked to wet deposition and steep slopes, whereas Moldovan samples showed higher Sr and Zn concentrations, likely driven by soil erosion in carbonate chernozems. The study highlights geogenic and climatic influences on element accumulation by moss, offering insights into the effectiveness of moss biomonitoring across heterogeneous landscapes. Full article