Joined-up governance for more complementary interactions between expanding artisanal small-scale gold mining and agriculture: Insights from Ghana.

Rising gold prices have led artisanal and small-scale gold mining (ASGM) operations to proliferate in sub-Saharan Africa, extending into agricultural areas. Little is known about the interactions between agriculture and mining in these new frontiers. This study aimed to investigate the impacts of ASGM on natural and physical livelihood capitals, ASGM's interactions with agriculture at household, community and institutional levels and the drivers underpinning those interactions, and the policy implications for the co-existence of sustainable agriculture and ASGM. Alongside literature review, field-work took place in Atiwa West District and Koforidua, Ghana using environmental field surveys, questionnaires, focus group discussions and interviews. Questionnaire and field survey data were analysed using descriptive statistics, with thematic analysis of interviews and focus group data. Findings revealed that most miners were unregulated, mined irresponsibly and degraded land, waterways, and farm roads. Over one-third of farmers (38%) suffered land degradation, and 79% of affected farmers' lands were not reclaimed. Farmers diversified into ASGM, and mining proceeds boosted farming. Young farmers (18-40 years) shifted into ASGM full-time because it is more lucrative. Yet, ASGM is not replacing agriculture: cocoa farming remains a vital economic activity. Informal ASGM generates short-term income at household level for some but imposes long-term costs at community level, linked to cumulative loss of agricultural land and degradation of forest areas and water bodies, creating tensions, and increasing vulnerability. Financial hardships faced by farmers, landowners' desire to benefit directly from gold and lack of law enforcement drive informal ASGM. There are no institutional linkages between the agricultural and mining sectors. More joined up governance across agriculture and mining is needed and between formal and informal (traditional) institutions. ASGM should be incorporated into broader rural development policy reforms that support farmers, incentivise miners to operate legally and responsibly and ensure effective stakeholder engagement.

Tracing anthropogenic mercury in soils from Fe-Hg mining/smelting area: Isotopic and speciation insights.

Mercury (Hg) stable isotope ratios supplemented by Hg solid speciation data were determined in soils in a former Fe-Hg mining/smelting area (Jedová hora, Czech Republic, Central Europe). The dominant Hg phase in the studied soils was found to be cinnabar (HgS). A secondary form of soil Hg(II) was represented by Hg weakly and strongly bound to mineral (micro)particles, as revealed by thermo-desorption analysis. These Hg species probably play a key role in local soil Hg processes and biogeochemical cycling. The Hg isotopic data generally showed small differences between HgS (-1.1 to -0.8‰; δ202Hg) and the soil samples (-1.4 to -0.9‰; δ202Hg), as well as limited isotopic variability within the two studied soil profiles. On the other hand, the detected negative δ202Hg shift (∼0.4‰) in organic horizons compared to mineral soils in the highly contaminated profile suggests the presence of secondary post-depositional Hg processes, such as sorption or redox changes. For the less contaminated profile, the observed Hg isotopic variation (∼0.3‰; δ202Hg) in the subsurface mineral soil compared to both overlying and underlying horizons is likely due to cyclic redox reactions associated with Hg isotopic fractionation. We assume that the adsorption of Hg(II) to secondary Fe(III)/Mn(III,IV)-oxides could be of major importance in such cases.

Assessment of the state of vegetation cover of recultivated dumps of uranium deposits in Northern Kazakhstan.

The purpose of this study was to assess the processes of plant community formation on recultivated dumps of spent uranium-containing industrial waste from uranium deposit mines, as well as to identify the degree of impact of agro-climatic factors, agrochemical indicators of soils of recultivated dumps, and the level of residual ionizing radiation on the productivity of the emerging vegetation cover. Studies of plant colonization of recultivated Grachevsky and Shantobinsky uranium mine dumps located in Northern Kazakhstan were carried out. The mining and technical stage of reclamation consisted of planning a dump with slopes of 15° and covering it with a 1 m layer of chestnut soil. In total, 30-35 plant species are present in the dumps, the projective coverage is approximately the same (56.6-70.0%), and the herbage density is 15-16.6 plants/100 m2. As a result of the measures taken to recultivate the dumps, the intensity of the background ionizing radiation at the Grachevsky mine dump was in the range of 25-35 µR/hr and at the Shantobinsky mine dump 10-25 µR/hr, which indicates compliance with safety standards. The plant species which can be used for artificial plant colonization of uranium-containing waste dumps, were identified.

Analysis of soil fertility and toxic metal characteristics in open-pit mining areas in northern Shaanxi.

The study specifically focused on the Hongliulin mining area, where a total of 40 soil samples were meticulously collected and analyzed from within a 1000 m radius extending from the tailings dam. The findings revealed that soil pH within the 0-1000 m range generally leaned towards the alkaline side. In terms of soil nutrient content, encompassing factors such as soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali nitrogen (AK), available phosphorus (AP), and quick-acting potassium (AK), the variations fell within the following ranges: 2.23-13.58 g/kg, 0.12-0.73 g/kg, 0.18-1.15 g/kg, 9.54-35.82 g/kg, 2.89-6.76 mg/kg, 3.45-11.25 mg/kg, and 5.86-130.9 mg/kg. Collectively, these values indicate relatively low levels of soil nutrients. Within the 0-500 m range of soil samples, the average concentrations of Cd, Hg, Pb, and As were 0.778, 0.198, 24.87, and 17.92 mg/kg, respectively. These concentrations exceeded the established soil background values of Shaanxi Province and emerged as the primary pollutants in the study area. Within this same range, the mean values of eight toxic metals (Pi) were ranked in the following descending order: 1.726 (Hg), 1.400 (As), 1.129 (Cr), 1.109 (Pb), 0.623 (Zn), 0.536 (Cd), 0.309 (Cu), and 0.289 (Ni). With the exception of Hg, As, Cr, and Pb, which exhibited slight pollution, the other toxic metals were found to be within acceptable pollution limits for this sampling range, in line with the results obtained using the geo-accumulation index method. The average potential ecological risk index for the eight toxic metals in the study area stood at 185.0, indicating a moderate overall pollution level. When assessing individual elements, the proportions of ecological risk attributed to Hg, As, Pb, and Cd were 34.57%, 27.44%, 25.11%, and 23.11%, respectively. This suggests that the primary potential ecological risk elements in the study area are Hg and As, followed by Cd and Pb. Notably, toxic metals Hg and Pb, as well as As and Pb, exhibited significant positive correlations within the sampling area, suggesting a common source. An analysis of the relationship between soil physicochemical properties and toxic metals indicated that soil pH, SOM, TN, and TP were closely linked to toxic metal concentrations. The toxic metal elements in the research area's soil exhibit moderate variability (0.16 < CV < 0.36) to high variability (CV > 0.36). Within the range of 0-200 m, the CV values for Cd and Hg exceed 1, indicating a high level of variability. The coefficient of variation for SOM, TP, AP, AK and TK is relatively high with the of 2.93, 2.36, 2.36, 21.01, 7.54. The soil in the sampling area has undergone significant disturbances due to human activities, resulting in toxic metal pollution and nutrient deficiencies.

Legacy coal mining impacts downstream ecosystems for decades in the Canadian Rockies.

Mountaintop removal coal mining leaves a legacy of disturbed landscapes and abandoned infrastructure with clear impacts on water resources; however, the intensity and persistence of this water pollution remains poorly characterized. Here we examined the downstream impacts of over a century of coal mining in the Crowsnest Pass (Alberta, Canada). Water samples were collected downstream of two historical coal mines: Tent Mountain and Grassy Mountain. Tent Mountain hosts a partially reclaimed surface mine that closed in 1983. Selenium concentrations downstream of Tent Mountain reached 185 µg/L in a lake below the mine spoil pile, and up to 23 µg/L in Crowsnest Creek, which drains the lake and the mine property. Further downstream, a well-dated sediment core from Crowsnest Lake records increases in sediment, selenium, lead, carbon, nitrogen, and polycyclic aromatic compounds that closely tracked the history of mining at Tent Mountain. In contrast, episodic discharge of mine water from abandoned underground adits at Grassy Mountain drive periodic (but short-term) increases in iron, various metals, and suspended sediment. These results underscore the lasting downstream impacts of abandoned and even reclaimed coal mines.

Paracelsian 'Bergsucht' - lung cancer or radiation-induced fibrosis?

PURPOSE: Assessment of absorbed doses on organs and tissues of miners during radon exposure in the Schneeberg mines in the sixteenth century and calculation of the probability of occurrence of radiation-induced lung cancer and lung fibrosis, considering the life expectancy characteristic and the absence of smoking. MATERIALS AND METHODS: The expected radon concentration at the Schneeberg mines has been estimated using published data. Modeling of the accumulation of radon in the working tunnels of mine workings was carried out using the RESRAD-Build 4.0, based on the radium concentration in soil and geometric parameters of the mining tunnel from the engravings in Agricola's book. The dynamics of radionuclides in the human body were performed using the WinAct software in accordance with data from ICRP Publications 130 and 137. The values of absorbed doses on the tissues of the respiratory tract were obtained using the IDAC 2.1 program. Several models based on the epidemiology of uranium miners have been used to calculate radiation risks from radon exposure. The probability of male survival at birth and the age-specific frequency of spontaneous lung cancer not associated with radiation for miners of the sixteenth century (nonsmoking men aged 20-40 years) were estimated to properly calculate the radiation risks. RESULTS: The expected radon concentration in the Schneeberg mines was assessed in the range of 75-100 kBq m-3. The average value of the equilibrium factor was estimated as 0.49 ± 0.03. The annual exposure of miners to radon decay products was assessed as 125-165 WLM year-1. The annual values of absorbed doses to different sections of the respiratory tract were calculated, the maximum absorbed doses of α-radiation are formed on the bronchial and bronchiolar regions of the lungs (2.23 Gy year-1). The deterministic effects as radiation fibrosis of the lungs with 10 years of experience in the mines of Schneeberg have a probability of occurrence from 60 to 100%. All the models used for radiation risk assessments showed that the lifetime risk of developing lung cancer for nonsmoking Schneeberg miners is many times lower than the risk of developing deterministic radiation effects. In contrast, for the smoking cohort of miners in the nineteenth century lung cancer become the dominant cause of death. CONCLUSIONS: The deterministic radiation effects of Schneeberg miners in sixteenth century, exposed to extremely high levels of radon, such as radiation pneumosclerosis or pulmonary fibrosis, are more likely than the development of radiation-induced lung cancer.

Bioremediation of uranium (â ¥) using a native strain Halomonas campaniensis ZFSY-04 isolated from uranium mining and milling effluent: Potential and mechanism.

A significant surge in the exploitation of uranium resources has resulted in considerable amounts of radioactive effluents. Thus, efficient and eco-friendly uranium removal strategies need to be explored to ensure ecological safety and resource recovery. In this study, we investigated the resistance of Halomonas campaniensis strain ZFSY-04, isolated from an evaporation pool at a uranium mine site, and its potential mechanism of uranium (Ⅵ) removal. The results showed that the strain exhibited unique uranium tolerance and its growth was not significantly inhibited under a uranium concentration of 700 mg/L. It had a maximum loading capacity of 865.40 mg/g (dry weight), achieved following incubation under uranium concentration of 100 mg/L, pH 6.0, and temperature 30 °C, for 2 h, indicating that the removal of uranium by the strain was efficient and rapid. Combined with kinetic, isothermal, thermodynamic, and microspectral analyses, the mechanism of uranium loading by strain ZFSY-04 was metabolism-dependent and diverse, including, physical and chemical adsorption on the cell surface, extracellular biomineralisation, intracellular bioaccumulation, and biomineralisation. Our results highlight the unique properties of indigenous strains, including high resistance, high efficiency, rapid uranium removal, and various uranium removal strategies, which make it suitable as a new tool for in situ bioremediation and uranium-contaminated environmental resource recovery.

Streptomyces rock phosphate ore biomining evaluation in vitro.

The process of extracting metals from rock phosphate ore (RPO) by using microorganisms to convert them into soluble compounds is called biomining. Phosphorus is one of the elements proposed to be extracted from RPO. To understand the role of Streptomyces phospholyticus, 12 isolates of Streptomyces were isolated from RPO, their ability to grow on specific phosphate solubilization medium e.g., National Botanical Research Institute's phosphate growth agar (NBRIP) was studied, and the best strain with a 3 cm clear zone was selected. Its ability to grow at increasing RPO concentrations from 0.01 to 1 kgl-1 was investigated. This strain showed good growth, with extracellular red pigmentation for all concentrations, but no clear zone. In the modified liquid NBRIP, however, the Streptomyces growth patterns of the two concentrations of 0.25 kg and 1 kgl-1 RPO showed growth of single spherical red colonies with rhizoids on the surface, the colonies somehow grew and became embedded in the fine RPO granules. This ability to grow can resist gamma irradiation with a dose of 32 KGy. Within 3 days of growth, acidic and alkaline phosphatase were 76.2 and 67.1 µg p-nitrophenol g-1 ml-1, respectively. The RPO analysis showed that the %P in the ore was 16.5% at the beginning of the experiment, and after Streptomyces biotreatment, this percentage decreased to 8.4%, with a decomposition rate of 50.7%. This study, to our knowledge, is the first to investigate the efficiency of Streptomyces in mining phosphate rock ore in the laboratory, even at high concentrations, and to examine the role of irradiation as a preservative in increasing this efficiency.

An analysis of the foremost issues with artisanal and small-scale gold mining from Ghana's perspective.

Ghana has abundant mineral reserves in many of its regions, and gold mining remains one of the country's main sources of revenue. Given Ghana's current position in the global gold market, this review provides insight into the ASGM sector to give an understanding of the pertinent issues in the sector and its role in the socio-economic development of the country. This review assesses the effects of ASGM operations in economic, social, health, and environmental contexts to raise awareness of issues related to ASGM. It evaluates the measures taken to lessen the consequences of ASGM and maintain the sector's long-term viability. This review considers the foremost issues, including continued Hg use in ASGM, recent use of cyanide in ASGM, pollution of water bodies, and toxic metal contamination. It takes into account sustainable measures and remedial techniques that Ghana has implemented to alleviate the negative effects and support best mining practices. The primary factors influencing people to participate in ASGM are the need for quick sources of income, the scarcity of jobs in rural areas, the economic hardship, the need to supplement earnings from other activities like trading, and the comparatively meager profits from agricultural activities. Findings indicated that to gain more traction in addressing the challenges in the ASGM sector, the involvement of the community and direct stakeholders is essential to promoting responsible mining and environmentally sustainable practices. This review will increase awareness and pressure on decision-makers, researchers, and ASGM communities about the relevance of environmental conservation and sustainability.

5-year leaching experiments to evaluate a modified bauxite residue: remediation of sulfidic mine tailings.

The ALTEO company produces approximately 300,000 tons per year of bauxite residue after alumina extraction, which is washed and dried in a press filter to produce Bauxaline®. In this study, different ways for recovering and reusing this residue were explored, namely transformation into a vegetated soil, use in acid mine drainage depollution, and application in sulfide-mine tailings remediation. The Bauxaline® was therefore transformed into modified bauxite residue (MBR), resulting in reduced alkalinity, salinity, and sodicity. To counterbalance the net acid generation potential of two sulfidic mine tailings with 1 mol H+ kg-1 (1.5% sulfide) and 3.3 mol H+ kg-1 (5.3% sulfide), respectively, various treatments were applied. These treatments included the addition of 10% MBR or 10% MBR plus limestone, or by limestone only, within 40-l lysimeters. Six lysimeters were monitored over a 5-year period to assess the long-term emissions from treated materials. Vegetation was tested under various conditions, and its impact on emission was evaluated. The emissions of mine tailings treated with MBR and limestone were very low. The mine tailings with limestone showed intermittent peaks of emission, probably due to the coating of calcite grain by ferric oxide, hindering contact with percolating water. Vegetation successfully grew in the treated tailings. This study demonstrated that the alkalinity of limestone can temporarily immobilize elements in sulfidic mine tailings, with a reduction factor of emissions of 300 and 40 for the two mine tailings, respectively. For long-term immobilization, the alkalinity provided by both limestone and MBR and the Al and Fe oxides of MBR are more effective and necessary for long-term immobilization, with a reduction factor of 300 and 900, respectively.

Exploring the Impact of Recycling on Demand-Supply Balance of Critical Materials in Green Transition: A Dynamic Multi-Regional Waste Input-Output Analysis.

Addressing our climate urgency requires various renewable and low-carbon technologies, which often contain critical materials that face potential supply risks. Existing studies on the critical material implications of green transition have used various methodologies, each with pros and cons in providing a system understanding. Here, we integrated the dynamic material flow analysis and input-output modeling principles in an integrated multi-regional waste input-output model to assess the demand-supply balance and recycling potentials for cobalt, lithium, neodymium, and dysprosium under various energy scenarios projected to 2050. We show that although all four critical materials are likely to face strong growth in annual demand (as high as a factor of 25 compared to the 2015 level), only cobalt has a higher cumulative demand by 2050 than the known reserves. Nevertheless, considering the sheer scale of demand increase and long lead time of opening or expanding new mines, recycling efforts are urgently needed to supplement primary supply toward global green transition. This model integration is proven useful and can be extended to more critical materials and green technologies.

Chemical and ecotoxicological indicators for evaluating the treatment of coal mining wastes.

This paper consists of the evaluation in regards to the ecotoxicological effectiveness of a treatment applied to a coal mining waste. The treatment consisted of separating the particles based on gravimetric concentration in spirals, generating three fractions: heavy, intermediate, and light, with high, moderate, and low pyrite content, respectively. The intermediate fraction represents the larger disposal volume of the waste on soils. To evaluate the effectiveness of the treatment, metal determination and bioassays Eisenia andrei, Folsomia candida, Lactuca sativa, Daphnia similis, and Raphidocelis subcapitata were applied to the intermediary fraction. To evaluate the toxicity to aquatic organisms, elutriates were generated from the unprocessed waste and the intermediate fraction. The intermediate fraction showed a decrease of metal concentrations compared to the untreated waste. Metal concentrations in the intermediate fraction were below the Brazilian thresholds for soil quality. Avoidance bioassay with E. andrei and germination tests of L. sativa showed no significant effects. The bioassay with F. candida indicated a significant reduction in reproduction at the highest doses used (24% and 50%). Bioassays with D. similis and R. subcapitata revealed a reduction in toxicity of the intermediate fraction compared to the untreated waste. However, the toxicity levels of the intermediate fraction to aquatic organisms still require attention, especially in regards to pH that played a crucial role in the toxicity. Finally, the results suggest that the treatment performed on the coal waste was efficient, even though significant toxicity have still been detected in the treated waste and additional steps are still required for adequate final disposal.

Geochemical distributions of natural radionuclides in surface soils and sediments impacted by lead-zinc mining activity.

This study investigated the distribution features of uranium-238 (238U), radium-226 (226Ra), thorium-232 (232Th), and potassium-40 (40K) and evaluated the associated environmental radiological hazards of the topsoil and river sediments in the Jinding lead-zinc (Pb-Zn) mine catchment from Southwest China. The activity concentrations of 238U, 226Ra, 232Th, and 40K ranged from 24.0 ± 2.29-60.3 ± 5.26 Bq.kg-1, from 32.5 ± 3.95-69.8 ± 3.39 Bq.kg-1, from 15.3 ± 2.24-58.3 ± 4.92 Bq.kg-1, and from 203 ± 10.2-1140 ± 27.4 Bq.kg-1, respectively. The highest activity concentrations for all these radionuclides were primarily found in the mining areas and decreased with increasing distance from the mining sites. The radiological hazard indices, including radium equivalent activity, absorbed gamma dose rate in the air, outdoor annual effective dose equivalent, annual gonadal dose equivalent, and excess lifetime cancer, revealed that the highest values were observed in the mining area and downstream, specifically in the vicinity of the ore body. These elevated values exceeded the global mean value but remained below the threshold value, suggesting that routine protection measures for Pb-Zn miners during production activities are sufficient. The correlation analysis and cluster analysis revealed strong associations between radionuclides such as 238U, 226Ra, and 232Th, indicating a common source of these radionuclides. The activity ratios of 226Ra/238U, 226Ra/232Th, and 238U/40K varied with distance, suggesting the influence of geological processes and lithological composition on their transport and accumulation. In the mining catchment areas, the variations in these activity ratios increased indicated the impact of limestone material dilution on the levels of 232Th, 40K, and 238U in the upstream region. Moreover, the presence of sulfide minerals in the mining soils contributed to the enrichment of 226Ra and the removal of 238U caused those activity ratios decreased in the mining areas. Therefore, in the Jinding PbZn deposit, the patterns of mining activities and surface runoff processes in the catchment area favored the accumulation of 232Th and 226Ra over 40K and 238U. This study provides the first case study on the geochemical distributions of natural radionuclides in a typical Mississippi Valley-type PbZn mining area and offers fundamental information on radionuclide migration and baseline radiometric data for PbZn deposits worldwide.

Alpha radiation from polymetallic nodules and potential health risks from deep-sea mining.

In search for critical elements, polymetallic nodules at the deep abyssal seafloor are targeted for mining operations. Nodules efficiently scavenge and retain several naturally occurring uranium-series radioisotopes, which predominantly emit alpha radiation during decay. Here, we present new data on the activity concentrations of thorium-230, radium-226, and protactinium-231, as well as on the release of radon-222 in and from nodules from the NE Pacific Ocean. In line with abundantly published data from historic studies, we demonstrate that the activity concentrations for several alpha emitters are often higher than 5 Bq g-1 at the surface of the nodules. These observed values can exceed current exemption levels by up to a factor of 1000, and even entire nodules commonly exceed these limits. Exemption levels are in place for naturally occurring radioactive materials (NORM) such as ores and slags, to protect the public and to ensure occupational health and radiation safety. In this context, we discuss three ways of radiation exposure from nodules, including the inhalation or ingestion of nodule fines, the inhalation of radon gas in enclosed spaces and the potential concentration of some radioisotopes during nodule processing. Seen in this light, inappropriate handling of polymetallic nodules poses serious health risks.

Radiological risk assessment of outdoor222Rn and220Rn around rare earth element and uranium mines from northern Vietnam.

The outdoor222Rn and220Rn concentrations at 320 sampling points at 1 m above the ground in different sites surrounding rare earth element (REE) and uranium mines from northern Vietnam were measured using the RAD7. Results showed that222Rn concentrations were always higher than220Rn concentrations with large variation ranges from 25.7 to 573 Bq m-3and from 18.5 to 385 Bq m-3, respectively. The high correlation between220Rn and228Ra concentrations in surface soil of the studied sites were observed. The highest220Rn and222Rn concentrations are found at the sampling points of the REE NX-Lai Chau site. The220Rn and222Rn activities surrounding the REE mines were found to be higher than those surrounding the uranium mines. The average annual committed effective doses originated from the inhalation of220Rn and222Rn outdoor concentrations is about five times higher than the worldwide average value.

Experimental study on radon retardation effect of modular covering floats in radon-containing water.

Radon-containing water bodies in uranium mining areas inevitably release radon gas, polluting the surrounding environment via radiation. Thus, it is particularly important to develop devices with the ability to retard the radon release from such water bodies. Based upon theories of radon exhalation in water, a radon exhalation retardation device (RERD) with flexible, modular floats (a flexible polyvinyl chloride material module that floats on water) was designed and manufactured. To study the modular surface-covering floats' effectiveness in retarding radon release from water surfaces, an experimental setup was constructed to simulate radon release from water bodies, using a granular uranium ore sample from a uranium mine as sediment material. Closed-loop measurements were taken to determine the radon exhalation rate on the exposed surface of the water in uncovered and covered conditions. Radon retardation rates were also compared for different area coverage (29.6%, 59.1%, and 88.7%) and immersion depths (0.02 m and 0.04 m) in unperturbed and perturbed water bodies. The results show that: 1) the greater the area coverage, the greater the radon retardation rate in both unperturbed and perturbed water bodies; 2) under the same coverage conditions, the surface radon exhalation rate and the radon transfer velocity at the gas-liquid interface of the perturbed water are larger than those of the unperturbed water; 3) The immersion depth of modular surface-covering floats has a stronger effect on the radon retardation rate in unperturbed water bodies than in perturbed water bodies. The study shows that the proposed modular floats are effective in retarding radon release from both perturbed and unperturbed water bodies.

A new hazard assessment workflow to assess soil contamination from large and artisanal scale gold mining.

Gold mining activities are undertaken both at large and artisanal scale, often resulting in serious 'collateral' environmental issues, including environmental pollution and hazard to human and ecosystem health. Furthermore, some of these activities are poorly regulated, which can produce long-lasting damage to the environment and local livelihoods. The aim of this study was to identify a new workflow model to discriminate anthropogenic versus geogenic enrichment in soils of gold mining regions. The Kedougou region (Senegal, West Africa) was used as a case study. Ninety-four soil samples (76 topsoils and 18 bottom soils) were collected over an area of 6,742 km2 and analysed for 53 chemical elements. Robust spatial mapping, compositional and geostatistical models were employed to evaluate sources and elemental footprint associated with geology and mining activities. Multivariate approaches highlighted anomalies in arsenic (As) and mercury (Hg) distribution in several areas. However, further interpretation with enrichment factor (EFs) and index of geoaccumulation (IGeo) emphasised high contamination levels in areas approximately coinciding with the ones where artisanal and small scale mining (ASGM) activities occur, and robust compositional contamination index (RCCI) isolated potentially harmful elements (PHE) contamination levels in very specific areas of the Kedougou mining region. The study underlined the importance of complementary approaches to identify anomalies and, more significantly, contamination by hazardous material. In particular, the analyses helped to identify discrete areas that would require to be surveyed in more detail to allow a comprehensive and thorough risk assessment, to investigate potential impacts to both human and ecosystem health.

Distribution and storage of uranium, and its decay products, in floodplain sediments.

Industrialised rivers contain legacy contaminants stored in their sediments and floodplain soils which may inhibit attainment of environmental quality criteria. The River Fal catchment, SW England, is impacted by inputs from uranium mining and clay production and serves as an exemplar for understanding the consequences of medium-term process dynamics in contaminated basins. Radionuclides were determined, by gamma spectroscopy, in six cores from the river floodplain with the aim of quantifying the activities of 238U, and its decay products, and the bomb fallout radionuclides137Cs and 241Am. Activity concentrations of 238U implied inputs from mining, accentuated by flood events and historic industrial accidents, whereas 210Pb activities included a significant input of unsupported 210Pb linked to processed mine spoil. The radionuclide inventories did not decrease systematically downstream revealing evidence of attenuation of particulate radionuclides within the river floodplain sediment column. Storage of legacy contaminants in fluvial systems, at levels in excess of contemporary environmental quality guidelines, emphasises the challenges posed by changing climatic conditions. This scenario raises significant consequences for the management of uranium-contaminated, fertile riverine floodplains within Europe.

Uncharted risk measures for the management of sustainable mining.

Governments commit to ensuring the welfare of their citizens by drafting and enforcing regulations that ultimately ensure the sustainability of mining. This study contributes to improving the sustainability of mining throughout the mine's lifecycle until the final destination of the mining products. We propose recommendations that address the sustainability of mining from a global perspective, framed around the United Nations Sustainable Development Goals (SDGs), following waste hierarchy with Common Agricultural Policies, and policies from the Green Deal on climate, energy, transport, and taxation. Tailings are the most significant source of environmental impact in mining operations and, therefore, must comply with controlling regulations through Tailings Management Facilities (TMFs). However, there have been several mining accidents involving TMFs worldwide. The recommendations begin during planning, preconstruction, and construction with practices such as fair consultations, tax revenue fairness, and mandatory insurance. The operation and management support parallel industries to mining and supporting health and education. Emergency planning involves the surrounding communities in mock drills and environmental monitoring. In the closure and rehabilitation, remediation technologies such as phytoremediation, carbon sequestration incentives, and biomass valorization are recommended. Finally, supporting a circular economy by prioritizing ethical consumption, resource reduction, material recovery, and replacing toxic minerals and materials from the start with "benign by design" is recommended. The strategies involve stakeholders directly or indirectly related to the mining companies' contamination and demonstrate a commitment to the SDGs, offering a holistic perspective on scientific, social, and regulatory issues. Integr Environ Assess Manag 2023;19:949-960. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Vegetation restoration effects on soil carbon and nutrient concentrations and enzymatic activities in post-mining lands are mediated by mine type, climate, and former soil properties.

Vegetation restoration is a widely used, effective, and sustainable method to improve soil quality in post-mining lands. Here we aimed to assess global patterns and driving factors of potential vegetation restoration effects on soil carbon, nutrients, and enzymatic activities. We synthesized 4838 paired observations extracted from 175 publications to evaluate the effects that vegetation restoration might have on the concentrations of soil carbon, nitrogen, and phosphorus, as well as enzymatic activities. We found that (1) vegetation restoration had consistent positive effects on the concentrations of soil organic carbon, total nitrogen, available nitrogen, ammonia, nitrate, total phosphorus, and available phosphorus on average by 85.4, 70.3, 75.7, 54.6, 58.6, 34.7, and 60.4 %, respectively. Restoration also increased the activities of catalase, alkaline phosphatase, sucrase, and urease by 63.3, 104.8, 125.5, and 124.6 %, respectively; (2) restoration effects did not vary among different vegetation types (i.e., grass, tree, shrub and their combinations) or leaf type (broadleaved, coniferous, and mixed), but were affected by mine type; and (3) latitude, climate, vegetation species richness, restoration year, and initial soil properties are important moderator variables, but their effects varied among different soil variables. Our global scale study shows how vegetation restoration can improve soil quality in post-mining lands by increasing soil carbon, nutrients, and enzymatic activities. This information is crucial to better understand the role of vegetation cover in promoting the ecological restoration of degraded mining lands.