Search Results (131)

Artisanal and small-scale gold mining (ASGM) generates complex metal mixtures, yet their biological effects remain poorly characterized in high-altitude populations, where occupational exposure occurs against a hypoxic environmental background. This study evaluated 49 occupationally exposed gold miners from the Vetas–California mining district, near the Santurbán páramo in Colombia, and 25 non-exposed individuals from a comparable high-altitude area. Hair concentrations of essential and toxic elements were quantified by ICP-MS, and serum catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), oxidized glutathione (GSSG), and the GSH/GSSG ratio were assessed. Miners showed a distinct multielement profile, with a higher toxic-metal burden and a dominant mixture mainly characterized by Fe, Mn, As, Pb, Cd, and Hg. CAT and SOD activities did not differ markedly between groups, although SOD activity decreased along the main exposure gradient among exposed workers. In contrast, glutathione-related biomarkers showed a more consistent exposure-related pattern, with higher GSSG and a lower GSH/GSSG ratio, suggesting a shift toward a more oxidized glutathione redox status. Together with positive within-group associations between selected elements and the GSH/GSSG ratio, these results are consistent with a mixture-associated perturbation of glutathione redox homeostasis, with heterogeneous adaptive responses. Overall, this study supports the use of integrated biomonitoring strategies and highlights glutathione-related markers as potential indicators of early redox perturbation in high-altitude mining populations. Full article

Mercury pollution from artisanal and small-scale gold mining remains one of the most persistent environmental threats due to the high toxicity, mobility, and bioaccumulation of Hg(II). In this work, Colombian banana pseudostem waste is valorized into a lignocellulosic carbocatalyst through pyrolysis at 500 °C followed by MnCO₃-derived MnOx functionalization, producing a sustainable material for Hg(II) remediation. The transformation of the biomass leads from a fibrous structure (~25 µm) to a pyrolyzed carbon matrix (9.56 µm), and finally to a heterogeneous Mn-modified system with bimodal particle distribution (~25 µm and ~0.85 µm), the latter being associated with highly dispersed MnOx redox-active domains. Structural and textural analyses reveal that Mn incorporation significantly enhances surface properties, increasing the BET surface area from 140.8 to 213 m² g⁻¹ while reducing pore size to the meso–microporous range (~1.9 nm). Importantly, the material retains intrinsic minerals such as Ca, Mg, K, and Si, which contribute to surface basicity and ion-exchange capacity, supporting additional Hg(II) interaction pathways. Optical and electronic characterization shows a wide band gap semiconductor behavior (≈3.4 eV) and a conduction band position at −0.892 V vs. NHE, sufficiently negative to thermodynamically drive Hg²⁺ reduction to Hg⁰ under UV-A irradiation. Hg(II) quantification was validated using a UV–Vis method based on the Hg²⁺–dipicolinic acid (DPA) complex, confirming stable complex formation with 1:2 stoichiometry (Hg²⁺:DPA) and high analytical reliability (R² = 0.948, LOD = 1.85 mg L⁻¹). Photocatalytic experiments demonstrated negligible Hg(II) reduction under UV-A light in the absence of catalyst, whereas the carbon-based materials enabled significant Hg transformation through adsorption-assisted photoinduced electron transfer. Electrochemical analyses (Rct ≈ 11 Ω) confirmed efficient charge transport, while cyclic voltammetry evidenced reversible Mn(IV)/Mn(III)/Mn(II) redox cycling, which sustains electron mediation during photocatalysis. Overall, pristine biochar acts primarily through adsorption driven by oxygenated functional groups and porous structure, whereas Mn-functionalized biochar operates via a synergistic adsorption–photocatalytic mechanism. In this system, MnOx species function as redox-active centers that facilitate electron transfer from the carbon matrix to Hg(II), while the conductive lignocellulosic-derived framework enhances charge mobility. The combination of structural carbon stability, dispersed Mn active sites, and inherent mineral functionality establishes a highly efficient and sustainable carbocatalyst, demonstrating a green and scalable approach for mercury remediation in mining-impacted regions. Full article

Small-scale artisanal mine production processes are characterized by significant environmental and human health impacts, especially in countries with ineffective economic resources and policies. This study accurately quantifies the impacts of artisanal gold production processes, identifying the dominating hotspots in a holistic perspective. The life cycle assessment (LCA) methodology was applied to perform an environmental sustainability appraisal for Doré and Cyanidation Gold (CyG) extraction from Mina Nueva, a small-scale artisanal mine managed by the local population, located in Asociación Campesina del Valle del río Cimitarra, near the city of Segovia in the department of Antioquia in Colombia. The obtained single-score LCA results showed a total damage of 4.99 × 10⁰² Pt, of which 55.2% was associated with the cyanidation process, 34.4% with the whole-ore amalgamation phase, and 10.4% with mine construction. A sensitivity analysis was also performed to study the potential effects of particulate emissions generated by the mine construction phase. Full article

Artisanal and Small-Scale Gold Mining (ASGM) is a primary source of global mercury pollution, creating an urgent need for sustainable, low-cost alternatives to amalgamation. This study investigates the use of cassava wastewater (manipueira), a cyanogenic agricultural byproduct, as a lixiviant for a gold concentrate (14.30–15.87 ppm Au) from an artisanal mine. Two approaches were evaluated: direct leaching with manipueira in natura (250 ppm CN⁻) in single and double 8 h and 12 h cycles, and leaching with a cyanide solution concentrated from dilute manipueira (100 ppm CN⁻) via a simplified air-stripping system. Results were benchmarked against the mine’s amalgamation (44.7% recovery) and 30-day heap leach (75.8% recovery) processes. The most effective method observed was a two-cycle, 8 h leach with manipueira in natura, which achieved a mean gold recovery of $76.75\pm 4.71\%$. This result is comparable to the efficiency of the site’s lengthy heap leach process and suggests a promising, faster, route to eliminating mercury use. Longer (12 h) leaching cycles yielded lower recoveries, suggesting process limitations such as preg-robbing. The cyanide concentration method proved inefficient, recovering a maximum of 12.40% of the available cyanide and resulting in a weaker lixiviant. The findings demonstrate that while direct leaching is a viable alternative to mercury, the inherent instability of manipueira necessitates a focus on developing efficient, controlled systems to extract and concentrate its cyanide content, thereby creating a standardized “green” reagent from a large-volume agricultural waste stream. Full article

Artisanal and small-scale gold mining (ASGM) constitutes an essential livelihood strategy for marginalized communities, yet it is also associated with severe environmental and social challenges. Persistent inequality and poverty underpin miners’ dependence on informal practices, where access to safer technologies is limited. Mercury use remains critical in ASGM, often mismanaged in processing, applied in amalgamation, and released into air, water, and soils. An estimated 1000–2000 tonnes are emitted annually despite Minamata Convention commitments. This paper examines how mining governance can foster sustainable transitions in ASGM, focusing on the Chilean National Mining Company (ENAMI) as a case study. ENAMI’s model—combining regulatory oversight, institutional support, and inclusive decision-making—shows how public governance can reduce mercury reliance, mitigate environmental degradation, and enhance social inclusion. Findings highlight the importance of regulation, community participation, capacity-building, and addressing structural inequalities as integral components of sustainability. The study argues that sustainable ASGM requires not only technical innovation but also culturally sensitive institutional reforms capable of overcoming resistance and promoting long-term behavioral change. By situating ASGM within the broader framework of sustainable rural development, this research provides insights for policymakers, practitioners, and scholars seeking to reconcile economic inclusion with environmental stewardship in vulnerable contexts. Full article

Mercury (Hg) pollution from artisanal and small-scale gold mining (ASGM) is a global environmental and public health concern. In Indonesia, ASGM remains widespread, yet assessments of multimedia contamination and health risks are limited. This study quantified Hg concentration in water, sediment, soil, fish, and cassava to evaluate environmental pollution and potential health risks in Waluran, Sukabumi, Indonesia. Mercury concentration in ASGM was higher than in the reference area, especially in fish (median: 4.76 mg/kg dw), cassava leaves (median: 15.7 mg/kg dw), and tailing sediments (median: 171 mg/kg dw). A remarkably high Hg concentration (9760 mg/kg dw) was detected in soil from amalgam-burning spots. An elevated Hg concentration was observed in the reference area, suggesting widespread contamination and potential for long-range dispersion. Over 85% of ASGM samples were categorized as heavily to extremely contaminated by the geo-accumulation index (I_geo). Bioaccumulation assessment indicated a high bioconcentration factor (BCF) in fish and moderate bioaccumulation factor (BAF) in cassava roots. Hazard Quotients (HQ) were greater than 1 for most exposure pathways in both adults and children, with the greatest risk deriving from cassava leaf consumption. These findings indicate severe Hg contamination within ASGM-affected communities and underscore the urgent need for public health interventions, environmental monitoring, and strengthened regulations to reduce Hg exposure in Indonesia. Full article

Mercury (Hg) is a globally recognized toxic element, and the Minamata Convention on Mercury entered into force in 2017 to address its associated risks. Under the United Nations Environment Programme, international efforts to reduce Hg emissions and monitor its environmental presence are ongoing. In support of these initiatives, we developed a simple and rapid mercury detection device based on a quartz crystal microbalance (QCM-Hg sensor), which utilizes the direct amalgamation reaction between Hg and a gold (Au) electrode. The experimental results demonstrated a proportional relationship between Hg concentration and the resulting oscillation frequency shift. Increased flow rates and prolonged measurement durations enhanced detection sensitivity. The system achieved a detection limit of approximately 1 µg/m³, comparable to that of commercially available analyzers. Furthermore, a measurement configuration integrating the reduction-vaporization method with the QCM-Hg sensor enabled the detection of mercury in aqueous samples. Based on the experimental results and the gas-phase detection sensitivity achieved to date, concentrations as low as approximately 0.05 µg/L appear to be detectable. These findings highlight the potential of the QCM-Hg system for on-site mercury monitoring. This review aims to provide a comprehensive yet concise overview of QCM-Hg sensor development and its potential as a next-generation tool for environmental and occupational mercury monitoring. Full article

Artisanal and small-scale gold mining (ASGM) in Burkina Faso increasingly relies on cyanide, intensifying concerns about environmental contamination and human exposure. This study assessed free cyanide levels in water and soil across three ASGM sites—Zougnazagmiline, Guido, and Galgouli. Water samples (surface and groundwater) and topsoil (0–20 cm) were analyzed using the pyridine–pyrazolone method. Data were statistically and spatially processed using SPSS version 29.0 and the Google Earth Engine in conjunction with QGIS version 3.34, respectively. A site conceptual model (SCM) was also developed, based on the literature review, field observations, and validation by multidisciplinary experts in public health, toxicology, ecotoxicology, environmental engineering, and the mining sector, through a semi-structured survey. The results showed that 9.26% of the water samples exceeded the WHO guideline (0.07 mg/L), with peaks of 1.084 mg/L in Guido and 2.42 mg/L in Galgouli. At Zougnazagmiline, the water type differences were significant (F = 64.13; p < 0.001), unlike the other sites. In the soil, 29.36% of the samples exceeded 0.5 mg/kg, with concentrations reaching 9.79 mg/kg in Galgouli. A spatial analysis revealed pollution concentrated near the mining areas but spreading to residential and agricultural zones. The validated SCM integrates pollution sources, transport mechanisms, exposure routes, and vulnerable populations, offering a structured tool for environmental monitoring and health risk assessment in cyanide-impacted mining regions. 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

The main problem associated with mining is the release of heavy metals into the environment, impacting the soil and overall environment. Mercury is one of the most contaminating heavy metals. It is present in soils, sediments, surface water, and groundwater. The objective of this research was to evaluate the phytoremediation carried out by the native plant Piper marginatum, in soils contaminated by mercury in an experimental lot in the municipality of Ayapel, where artisanal and small-scale gold mining is carried out. A soil phytoremediation process was carried out at a field scale using the plant species Piper marginatum in a 2.4 ha plot historically contaminated by gold mining, located in Ayapel, Colombia. A completely randomized experimental design was used with nine experimental plots, which were planted with Piper marginatum, and three controls, without planting. Through an initial soil sampling, the physicochemical characteristics and total mercury content in this matrix were determined. Piper marginatum seedlings were planted in the experimental plots and remained in the field for a period of six months. The plant biomass was collected and a final soil sampling was performed for total mercury analysis to determine the total percentage of mercury removal. The results obtained indicated mercury concentrations in soils ranging from 40.80 to 52,044.4 µg kg⁻¹ in the experimental plots and ranged from 55.9 to 2587.4 µg kg⁻¹ in the controls. In the plots planted with Piper marginatum, a 37.3% decrease in total mercury was achieved, while in the plots without planting there was a 23.5% increase. In plants, the average T Hg concentrations in the roots, stems, and leaves were 109.2 µg kg⁻¹, 80.6 µg kg⁻¹, and 122.6 µg kg⁻¹, respectively. An average BCF < 1 and an average TF > 1 were obtained. Full article

Artisanal small-scale gold mining (ASGM) is the largest source of global mercury (Hg) emissions. This study investigated Hg contamination in water, soil, sediment, fish, and cassava plants around ASGM sites in Gunung Pongkor, West Java, Indonesia. Hg concentration ranged from 0.06 to 4.49 µg/L in water; 0.420 to 144 mg/kg dw in soil; 0.920 to 150 mg/kg dw in sediment; 0.259 to 1.23 mg/kg dw in fish; 0.097 to 5.09 mg/kg dw in cassava root; and 0.350 to 8.84 mg/kg dw in cassava leaf. Geo-accumulation index (Igeo) analysis revealed moderate to heavy soil contamination upstream, likely due to direct ASGM input. In contrast, sediment Igeo values indicated heavy contamination downstream, suggesting Hg transport and sedimentation. Bioconcentration factors (BCFs) in fish were predominantly high in downstream and midstream areas, indicating enhanced Hg bioavailability. Bioaccumulation factors (BAFs) in cassava were higher in upstream areas. Health risk assessment, based on the Hazard Quotient (HQ) and Hazard Index (HI), identified ingestion as the primary exposure route, with children exhibiting significantly higher risks than adults. These findings highlight the significant Hg contamination associated with ASGM in Gunung Pongkor and emphasize the need for targeted mitigation strategies to protect human and environmental health. Full article

This research aims to define an operational plan for the sustainability of small-scale artisanal gold mining (ASGM) in Northeast Antioquia, Colombia. A qualitative approach with a descriptive scope was used, for which a documentary or bibliographical review technique was made. Accordingly, articles, theses, books and institutional documents were reviewed as any contribution to the research topic. Likewise, this documentation contributed to defining aspects for elaborating the operational plan. Based on the reviewed sources, the need was found to propose an operational plan for this area to contribute to sustainability. Based on the sustainability analysis of ASGM in the zone, three common factors could be identified within the various positions proposed: the environmental, economic, and socio-cultural dimensions. With these, different needs were recognised in the area of study that still need action. An operational plan was devised to address these challenges and support the sector’s long-term sustainability. Full article

This research quantifies mercury use and models its transport in artisanal and small-scale gold mining (ASGM) in the Lom River during two key periods of intense mining activities and high water flow. Mercury concentrations from mining surfaces were estimated using a soil input function approach. Industrial mercury releases were assessed with a ratio-based approach using official gold production data and the mercury-to-gold ratio. The PEGASE model was applied to simulate mercury transport and pollution in the Lom River and to analyze the pressure–impact relationships of ASGM activities on surface water. Field measurements of the mercury concentrations in the Lom River during the dry and rainy seasons of 2021 were used to validate modeling results. The results indicate that volatilization has a more significant impact on the predicted mercury concentrations than photodissociation. Three scenarios were modeled for mercury use: whole ore amalgamation (WOA), combined whole and concentrate ore amalgamation (WOA + COA), and concentrate ore amalgamation (COA). Mercury use estimates ranged from 2250–7500 kg during intense activity to 1260–4200 kg during high water for the gold production of 750 and 525 kg, respectively. Industrial discharges dominated mercury pollution during the dry season while leaching from mining surfaces was the primary contributor during the rainy season. Full article

This study evaluates DNA damage and multi-element exposure in populations from La Mojana, a region of North Colombia heavily impacted by artisanal and small-scale gold mining (ASGM). DNA damage markers from the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, including micronucleated binucleated cells (MNBN), nuclear buds (NBUDs) and nucleoplasmic bridges (NPB), were assessed in 71 exposed individuals and 37 unexposed participants. Exposed individuals had significantly higher MNBN frequencies (PR = 1.26, 95% CI: 1.02–1.57, p = 0.039). Principal Component Analysis (PCA) identified the “Soil-Derived Mining-Associated Elements” (PC1), including V, Fe, Al, Co, Ba, Se and Mn, as being strongly associated with high MNBN frequencies in the exposed population (PR = 10.45, 95% CI: 9.75–12.18, p < 0.001). GAMLSS modeling revealed non-linear effects of PC1, with greater increases in MNBN at higher concentrations, especially in exposed individuals. These results highlight the dual role of essential and toxic elements, with low concentrations being potentially protective but higher concentrations increasing genotoxicity. Women consistently exhibited higher MNBN frequencies than men, suggesting sex-specific susceptibilities. This study highlights the compounded risks of chronic metal exposure in mining-impacted regions and underscores the urgent need for targeted interventions to mitigate genotoxic risks in vulnerable populations. Full article

Artisanal and small-scale gold mining (ASCGM) provides a livelihood for many communities worldwide, but it has profound environmental impacts, especially on the quality of nearby water resources. This study assessed the impacts of ASCGM on the physicochemical quality of water and sediments from Kitengure stream, Buhweju Plateau, Western Uganda. Surface water (n = 94) and superficial sediments (n = 36) were sampled between October 2021 and January 2022 from three different sections of Kitengure stream (upstream, midstream around the ASCGM area, and downstream). The samples were analyzed for various physicochemical parameters and selected potentially toxic elements (PTXEs), namely: zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), and arsenic (As). A health risk assessment was performed using the hazard index and incremental life cancer risk methods. Pearson’s bivariate correlation, geoaccumulation, and pollution indices were used to establish the sources and potential risks that PTXEs in sediments could pose to aquatic organisms. The results indicated that water in Kitengure stream draining the ASCGM site was highly colored (1230.00 ± 134.09 Pt-co units; range = 924.00–1576.00 Pt-co units) and turbid (194.75 ± 23.51 NTU; range = 148–257 NTU). Among the five analyzed PTXEs, only Cd (0.082 ± 0.200–0.092 ± 0.001 mg/L) and Cu (0.022 ± 0.004–0.058 ± 0.005 mg/L) were detected in water, and Cd was above the permissible limit of 0.003 mg/L for potable water. Upon calculating the water quality index (WQI), the water samples were categorized as very poor for upstream samples (WQI = 227) and unfit for use (WQI = 965 and 432) for midstream and downstream samples, respectively. In sediments, the mean concentration ranges of Zn, Cd, Pb, Cu, and As were 0.991 ± 0.038–1.161 ± 0.051, 0.121 ± 0.014–0.145 ± 0.025, 0.260 ± 0.027–0.770 ± 0.037, 0.107 ± 0.017–0.422 ± 0.056, and 0.022 ± 0.002–0.073 ± 0.003 mg/kg, respectively, and they were all below their average shale, toxicity reference, and consensus-based sediment quality guidelines. Geoaccumulation indices suggested that there was no enrichment of the elements in the sedimentary phase and the associated ecological risks were low. However, there were potential non-carcinogenic health risks that maybe experienced by children who drink water from Kitengure stream. No discernable health risks were likely due to dermal contact with water and sediments during dredging or panning activities. It is recommended that further studies should determine the total mercury content of water, sediments, and crops grown along the stream as well as the associated ecological and human health risks. Full article