Artisanal Gold Mining Activities Research Articles

Repeated mining accounts for the majority of artisanal and small-scale gold mining activity in Southeastern Peru

Artisanal and small-scale gold mining (ASGM) is considered a leading cause of environmental degradation in the Amazon. Previous studies have only used deforestation to quantify total ASGM activity and have not considered that mining may occur multiple times in the same area. However, miners often revisit previously mined sites to extract additional gold, though the frequency and extent of this occurrence remains unquantified. This study is the first to quantify repeat ASGM in Madre de Dios, Peru, and to identify which factors best predict revisitation. We found that nearly two-thirds of total ASGM activity in this region is repeat mining. When repeat mining activity is accounted for, we found that 249 488 ha were mined from 1984–2021, which is 265% more than activity estimates based on deforestation due to initial ASGM alone. Random Forest modeling showed that the designation, region, size, and type of a mine were the most important predictors of repeat mining. We suggest that repeat mining must be considered for a more comprehensive view of ASGM activity and its environmental impacts.

Assessing the strategic applications of remote sensing for addressing illicit artisanal and small-scale gold mining activities

Assessing the strategic applications of remote sensing for addressing illicit artisanal and small-scale gold mining activities

Possible Risk Factors and Their Potential Associations with Combined Heavy Metal Exposures in Pregnant Women in the Republic of Suriname.

The exposure of pregnant women to multiple environmental pollutants may be more disadvantageous to birth outcomes when compared to single-compound contaminations. This study investigated the mixed exposures to mercury, manganese, or lead in 380 pregnant Surinamese women. The factors that might be associated with the heavy metal exposures and the relative risk of the potential factors to cause the mixed exposures were explored. The influencing factors of exposures to mixed contaminants assessed were living in Suriname's rural regions, several parts of which are contaminated with heavy metals emitted from artisanal and small-scale gold mining and agricultural activities; the consumption of potentially contaminated foods; advanced maternal age; as well as a relatively low formal educational level and monthly household income. Descriptive statistics were used to calculate frequency distributions and χ2-contingency analyses to calculate associations and relative risks (RR) with 95% confidence intervals (CI). Blood levels of two or three of the heavy metals above public health limits were observed in 36% of the women. These women were more often residing in the rural regions, primarily consumed potentially contaminated food items, were 35 years or older, were lower educated, and more often had a lower household income. However, only living in the rural regions (RR = 1.48; 95% CI 1.23-1.77) and a low household income (RR = 1.38; 95% CI 1.15-1.66) significantly increased the risk of exposure exceeding levels of concern to two or three of the heavy metals (by 48% and 38%, respectively). More comprehensive pharmacological, ecological, and epidemiological studies about exposures to mixed heavy metal contaminations in pregnant women are warranted.

A responsible mining approach to the economic modeling of small-scale gold mining

Artisanal mining, known as “garimpo” in Brazil, is a legal activity predicted in the Brazilian mining code. However, society's concern over the sustainable development of the Amazon rainforest and media coverage of illegal gold extraction have had the effect of marginalizing and condemning the sector as a whole. Known in the international literature as small-scale and artisanal gold mining (ASGM), this sector involves millions of miners across the world and hundreds of thousands in Brazil, who make a living from it, feed their families, and foster local economies. However, ASGM miners use techniques and operating procedures that, if not controlled, mitigated and eventually replaced, could lead to significant social and environmental impacts. There are growing concerns over ASGM activities, and buyers, investors, and industrial sectors are willing to pay more for a product created in a responsible manner. However, questions remain as to how much the transition to a responsible operation would cost, and whether buyers would really be willing to pay for it. This research presents a proposal for the economic modeling of ASGM operations based on immersive work in three cooperatives of legal ASGM miners in Brazil. The proposed approach considers the SDGs (United Nations Sustainable Development Goals) of the 2030 agenda, as applied to small-scale mining, and the corresponding actions that are needed, based on a detailed survey of the costs of the analyzed operations, with the aim of guiding small-scale mining activities towards greater responsibility and sustainability. In the proposed model, the average profit obtained from mining operations is guaranteed and the size of the bonus reverts to the responsible areas surveyed. A financial analysis based on our responsible model, which was developed for the cash flow for a hypothetical operation over 10 years, yields an IRR of 54 % and a payback of 2.54 years, thus demonstrating its economic viability.

Soil and environment quality in artisanal small-scale mining areas in western Côte d’Ivoire

Artisanal small-scale gold mining activities grow in different regions of Côte d’Ivoire, causing enormous soil and environmental damages. This study was conducted in the vicinity of illegal artisanal small-scale gold mining zones to investigate soil quality using environmental assessment tools, mainly pollution and geochemical accumulation indexes. The mining spoil from artisanal pits was sampled directly between 0 and 20 cm, collecting 500 g of soil per sampling point. Sub-samples of soil were analyzed for multi-element using X-ray fluorescence technique. The results of the XRF analysis revealed higher trace element levels at some sampling points than the recommended levels. High arsenic concentrations were identified at three sampling sites: cavally sites with 7.09 and 16.08 mg kg-1 and Zérégbo with 9.57 mg kg-1. Moreover, significant concentrations of Cu and Pb were found at the Cavally site whilst Singouiné and Zérégbo showed high concentrations of Co and Cr. The study, globally, revealed the environmental hazards caused by the organized artisanal mining.

Prenatal arsenic and mercury levels among women practicing geophagy in areas with artisanal and small-scale gold mining activities, Northwestern Tanzania

BackgroundArtisanal and small-scale gold mining (ASGM) areas potentially pose increased exposure to arsenic and mercury through community contamination, occupations at gold mines, and/or geophagy when soil is locally sourced. This study examined the effects of geophagy, a deliberate soil eating practice, along with community and occupational exposures in ASGM areas on urinary arsenic and blood mercury levels among pregnant women in the Mining and Health Longitudinal Cohort in northwestern Tanzania.MethodsData on maternal arsenic and mercury levels were captured for 1056 pregnant women using an unprovoked morning urine samples and dried blood spots respectively. We used a step-wise generalized linear regression model to retain the most relevant covariates for the model. A generalized linear regression model with identity link function was used to predict the effect of geophagy practices on arsenic and mercury levels separately. The model was adjusted using sociodemographic correlates, including maternal age, education level, whether respondents lived in mining or non-mining area, years of residence, marital status, maternal occupation, individual partner’s education, and occupational, and socioeconomic status.ResultsIn the adjusted regression model, eating soil during pregnancy increased arsenic concentration by almost 23% (β = 1.229, 95% CI: 1.094, 1.38, p < 0.001) and living in mining areas had a 21.2% (β = 1.212; 95% CI: 1.039,1.414, p = 0.014) increased risk. Geophagy significantly increased mercury levels by 13.3% (β = 1.133, 95% CI: 1.022, 1.257, p = 0.018). Living in areas with ASGM activities was associated with a 142% (β = 2.422, 95% CI: 2.111, 2.776, p < 0.0001) increase in blood mercury.ConclusionGeophagy practices increased urinary arsenic and blood mercury levels in pregnant women, which was especially true for arsenic when living in areas with ASGM activities. Working in mining = increased risk for blood mercury levels. Community-based environmental health policies should address reductions in occupational and community exposures, along with strategic geophagy reduction interventions.

Economic valuation of artisanal small-scale gold mining impacts: A framework for value transfer application

Illegal artisanal and small-scale gold mining (ASGM) activities have serious environmental and health consequences. In this study, we developed a framework for calculating the economic costs associated with the negative environmental and social impacts of ASGM in the Brazilian Amazon. Based on a literature review on impact valuations of deforestation, land degradation, and mercury contamination, we used multiple parameters to develop a generalizable value transfer formula. The formula relates input variables, such as mining site area, pit depth, gold extraction productivity, and other context variables (population density, per capita income, average daily fish consumption, and transportation cost for restoration) to calculate the average monetary values associated with the impact. Additionally, we propose an enhancement to the model used by Bakker et al. (2021) for estimating mercury impacts on human health. Our findings show that values associated with social and environmental damage range from US$ 187,200 to US$ 389,200 per kilogram of gold, which is mostly attributable to health outcomes related to mercury contamination, which represents more than twice the market value of gold. Furthermore, we conducted a case study for the Tapajós Basin, which revealed that the socioeconomic costs generated by 4,547 ha of alluvial ASGM in the basin surpasses US$ 1 billion for the year 2020.

Elemental composition and speciation trends in Upper Mazowe River, a typical sub-tropical river ecosystem impacted by gold mining and agriculture in Zimbabwe

This study was carried on Upper Mazowe River in Zimbabwe which connects with Luenha River in Mozambique, which is a tributary of the Zambezi River. Zambezi River is the fourth longest river in Africa flowing into the Indian Ocean, which makes the study of regional and global interest. Heavy metal aqueous speciation has received relatively little attention compared to sediment speciation in the Upper Mazowe River, and yet heavy metal behaviour and fate in surface waters are greatly affected by the heavy metal chemical form in solution. The aim of the study was to determine the elemental composition and speciation of heavy metal(oid)s. This study focused on water and sediment speciation of Al, As, Cu, Hg, Mn, Fe, and Pb using Visual MINTEQ Version 3.1 computer modelling and sequential extraction techniques. Twenty-eight different water column elemental species, comprising 3, 2, 3, 1, 7, 7 and 5 species each, and 35 sediment phase elemental species, comprising 6, 6, 6, 2, 6, 5, and 4 species each for Al, As, Cu, Hg, Mn, Fe, and Pb respectively, were identified. Of note is the fact that Hg, mainly derived from artisanal gold mining activities, exists entirely as the fulvic acid complex, FA2Hg (aq), and As exists as H3AsO3 and H2AsO3− in the water phase. Exchange equilibrium reactions across the water-sediment interface were observed for Mn2+, Fe2+, Cu2+, and Pb2+. Reactions leading to the formation of the species were identified. Species interactions within the water column and sediment phase and species interrelationships with physicochemical parameters are discussed. H3AsO3 formation is predicted to be temperature sensitive and the aluminium hydroxide-fulvic acid complex /FA2(AlOH) (aq) is oxic favourable.

Predicting the loss of forests, carbon stocks and biodiversity driven by a neotropical ‘gold rush’

The loss of tropical forests represents a major threat to biodiversity. With accelerating deforestation in large parts of the Amazon, the Guiana Shield region, with its large expanse of closed forest cover, has the potential to play a crucial role in both climate change mitigation and biodiversity conservation. However, the region is now facing increasing deforestation pressures, primarily from artisanal gold mining activities concentrated in the nation of Guyana. To identify areas of Guyana at the highest risk of deforestation over the next 25 years, we employed a spatio-temporal modelling approach that accounted for the stochastic and contagious nature of deforestation. Our model predicted a 9 % net decrease in total forest cover by 2043. While the primary drivers of deforestation were mining and human settlements, protected areas were shown to reduce the probability of deforestation. Therefore, we assessed the potential impact of a proposed expansion of the protected area network in Guyana, on forest loss, carbon stocks and habitat loss for the country's most threatened forest vertebrates. Establishing the proposed protected areas would reduce forest loss by 17 %, predicted habitat losses by an average of 1.9 % per vertebrate group, and aboveground carbon emissions by 466,968 t over the next 25 years. These findings highlight the utility of using predictive models to identify areas at risk of future deforestation, which can contribute to the development of effective strategies against tropical forest loss, biodiversity loss and climate change.

Environment Degradation, Health Threats, and Legality at the Artisanal Small-Scale Gold Mining Sites in Indonesia.

Artisanal Small-scale Gold Mining (ASGM) activities, despite offering numerous economic incentives, inflict negative impacts on the environment and public health due to the use of mercury or cyanide. This study aims to compare three ASGM locations in Indonesia in terms of environmental impacts and potential health problems in the community. As part of this research, field surveys at three ASGM illegal locations with different conditions, observations, literature studies, and interviews with the community and stakeholders were conducted. At each of the survey sites, the potential threat to public health due to the use of mercury was determined to be high. Additionally, many of the environmental impacts detected were deemed to have reached a high-alert stage, in some cases even posing a level of extreme danger. Based on these results, it has become clear that a form of mining management which reduces the negative impacts on the surrounding environment and community health is needed. The suggestions put forward in this paper, including the call for greater control of ASGM, may also be applied in other developing countries which suffer from similar problems and conditions.

Hydrogeochemistry and Mercury Contamination of Surface Water in the Lom Gold Basin (East Cameroon): Water Quality Index, Multivariate Statistical Analysis and Spatial Interpolation

Artisanal and small-scale gold mining activities have an impact on natural resources and human health. This study addresses the assessment of surface water quality in the Lom gold basin. A combined approach of water quality index calculation, multivariate statistical analysis and spatial interpolation was used. Sampling was performed at 15 stations during low- and high-water periods in 2021 for classical physicochemical parameters and total mercury measurements. The results show that the physicochemical parameters were below drinking water standards for both periods, except for pH, total suspended solids and total mercury. These waters show a large cation deficit as well as an anion deficit. The water chemistry is controlled by precipitations and silicate dissolutions in rock that convert the water into the Ca-HCO3 and Ca-Mg-HCO3 types. The level of mercury contamination varied from acceptable to high due to high flow rates during high water that cause a dilution effect for the mercury concentration upstream and its accumulation downstream. The water quality varied from excellent to very poor with better quality during the high-water period. The Lom watershed is locally affected by physical and chemical pollution due to the abundance of suspended solids and mercury resulting from the different gold mining activities.

Green Gold Production from Primary and Secondary Resources

The exceptional chemical resistance of gold is a significant property of this precious metal, but it can pose challenges when it comes to gold extraction. Many metallurgical processes rely on highly aggressive or toxic reagents, and artisanal and small-scale gold mining activities, in particular, have faced criticism due to their difficult-to-control environmental impact. With growing ecological concerns, society and industry are compelled to seek efficient gold recovery methods that replace the use of mercury or cyanide. Over the past decades, extensive research has been conducted on alternative leaching reagents, showing promising technical and environmental characteristics. Various demonstration and pilot-scale application tests worldwide have provided valuable insights for potential industrial implementation. However, to date, only one industrial-scale application using the cyanide alternative thiosulfate has been reported. Apart from chlorination or aqua regia in refineries and recycling specific waste streams, there is a lack of notable industrial applications for cyanide alternatives, particularly in gold recycling from secondary resources. This is significant as it could have a substantial ecological impact by reducing the need for mining activities. For instance, electronic waste, which is increasing in volume and importance, represents a resource for gold recovery but lacks an efficient decentralized process. This work discusses the potential of cyanide alternative reagents for industrial application in gold production and recycling, while exploring various factors that contribute to the limited acceptance among gold producers.

High blood lead levels of children in a gold mining community in Osun State, Nigeria: an urgent call for action.

Environmental exposure from artisanal gold mining activities is a major risk for high blood lead levels (BLLs) in children. Over the last decade, artisanal gold mining activities have been on a sharp increase in some parts of Nigeria. This study compared BLLs of children in the mining community of Itagunmodi and a 50-km distant non-mining community of Imesi-Ile, Osun State, Nigeria. This community-based study investigated 234 apparently healthy children, with 117 each from Itagunmodi and Imesi-Ile. Relevant history, examination and laboratory findings including BLLs were recorded and analysed. All participants had BLLs above the cut-off value of 5µg/dl. However, the mean BLL of subjects living in the gold-mining community (24.2±5.3µg/dl) was significantly higher than for children in the non-mining area of Imesi-Ile (19.5±6.4µg/dl; p<0.001). Children in the gold mining community were 3.07 times more likely to have a BLL ≥20µg/dl than those in the non-mining environment (odds ratio [OR] 3.07 [95% confidence interval {CI} 1.79 to 5.2], p<0.001). Similarly, the odds of having a BLL ≥30µg/dl was 7.84 times more likely among children living in gold mining Itagunmodi than in Imesi-Ile (OR 7.84 [95% CI 2.32 to 26.46], p<0.0001). BLL was not associated with socio-economic and nutritional status of the participants. In addition to introduction and enforcement of safe mining practices, regular screening for lead toxicity is advocated for children in these communities.

Plankton diversity and its heavy metal content in Ratai Bay of Pesawaran district, Lampung, Indonesia.

Artisanal and small-scale gold mining (ASGM) activity in Way Ratai River produces heavy metal wastes; therefore, further information regarding heavy metal concentrations in the water was needed, especially in plankton samples. Furthermore, the determination of plankton diversity was also carried out in the waters of Way Ratai to determine the bioconcentration factor (BCF). Eight sampling sites were chosen along the river reaching the coast of Way Ratai. The research was conducted in November 2020 and March 2021. Ten heavy metals, Ag, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn that are commonly found in mining areas, were determined in the water and plankton samples by using ICP-OES. The results indicated that the highest concentration found was Fe in plankton samples (0.725 mg/L in the river and 1.294 mg/L on the coast). Meanwhile, contents of Cd, Cu, Fe, Mn, and Zn in the river exceeded the predetermined water quality standards, while Ag and Pb metals were not detected. The Cd, Cr, Cu, Pb, and Zn content in seawater also exceeded quality standards. The highest BCF value (12.96) was found for Fe at station G, whereas the lowest BCF value (0.13) was found for Ag at stations G and H.

Bacterial Metal-Scavengers Newly Isolated from Indonesian Gold Mine-Impacted Area: Bacillus altitudinis MIM12 as Novel Tools for Bio-Transformation of Mercury.

Selikat river, located in the north part of Bengkulu Province, Indonesia, has critical environmental and ecological issues of contamination by mercury due to artisanal small-scale gold mining (ASGM) activities. The present study focused on the identification and bioremediation efficiency of the mercury-resistant bacteria (MRB) isolated from ASGM-impacted areas in Lebong Tambang village, Bengkulu Province, and analyzed their merA gene function in transforming Hg2+ to Hg0. Thirty-four MRB isolates were isolated, and four out of the 34 isolates exhibited not only the highest degree of resistance to Hg (up to 200ppm) but also to cadmium (Cd), chromium (Cr), copper (Cu), and lead (Pb). Further analysis shows that all four selected isolates harbor a merA operon-encoded mercuric ion (Hg2+) reductase enzyme, with the Hg bioremediation efficiency varying from 71.60 to 91.30%. Additionally, the bioremediation efficiency for Cd, Cr, Cu, and Pb ranged from 54.36 to 98.37%. Among the 34, two isolates identified as Bacillus altitudinis possess effective and superior multi-metal degrading capacity up to 91.30% for Hg, 98.07% for Cu, and 54.36% for Cr. A pilot-scale study exhibited significant in situ bioremediation of Hg from gold mine tailings of 82.10 and 95.16% at 4- and 8-day intervals, respectively. Interestingly, translated nucleotide blast against bacteria and Bacilli merA sequence databases suggested that B. altitudinis harbor merA gene is the first case among Bacilli with the possibility exhibits a novel mechanism of bioremediation, considering our new finding. This study is the first to report the structural and functional Hg-resistant bacterial diversity of unexplored ASGM-impacted areas, emphasizing their biotechnological potential as novel tools for the biological transformation and adsorption of mercury and other toxic metals.

Emerging mercury and methylmercury contamination from new artisanal and small-scale gold mining along the Nile Valley, Egypt

The past decade witnessed the initiation and boom of the Artisanal and Small-scale Gold Mining (ASGM) activities in the hyper-arid southern Egypt. The ores are mined in the Eastern Desert and then transported to the densely populated farming communities in the Nile Valley, where the river provides the water resources needed for ore processing. In search for economic benefits, the poorly educated farmers with limited technical resources transformed their cultivated lands into ASGM operations, exposing themselves, their families, the residents, and the Nile ecosystems to several environmental and occupational health problems. Using integrated remote sensing, field, geochemical, and isotopic analyses, we report the first inventory of ASGM-related total mercury (THg) and methylmercury (MeHg) levels in tailings, amalgamation-tailing ponds, and surface and groundwater with emphasis on the Edfu city and its surroundings. The field and remote sensing-based mapping of ASGM activities reveals clustering around the Nile waterways and suggests interaction of Hg contamination sources with their surrounding receptors. Common ASGM practices include release of contaminated water from unlined amalgamation-tailing ponds into irrigation and drainage canals, and spreading of tailings over cultivated soils. In a short period (10 years), the released Hg contaminated multiple media, including the surface water, the shallow and deep aquifers, and possibly the soil, crops, and livestock. THg levels in amalgamation-tailing ponds (1200–8470 ng/L) are fourfold higher than US EPA and eightfold the WHO thresholds. The contaminated waters released from amalgamation-tailing ponds raised THg levels in surface water (irrigation canals: 50–100 ng/L; drainage canals: THg: > 200 ng/L) and groundwater (shallow and deep aquifers: 80–500 ng/L). Our findings highlight the need to extend the adopted approach to cover the entire length of the Nile River and its valley and the importance of conducting awareness campaigns to educate residents and health care providers about potential ASGM-related environmental and health hazards.Graphical

Detection and mapping abandoned areas of artisanal and small-scale gold mining (ASGM) using multi-sensor data on Google Earth Engine: A case study of Kuantan Singingi, Riau

Artisanal and small-scale gold mining (ASGM) activities in Kuantan Singingi, Riau have been operating over a decade without proper permits and using unsafe procedures for the environment. Mercury releases and degraded land have been the leading factors in the decreased environmental functions. ASGM activities are nomadic and secluded, posing a considerable challenge in detecting their location and extent. The aims of this study are to provide a method for detecting and mapping ASGM footprints utilizing multi-sensor data on cloud computing platforms. The detection method is performed using a supervised random forest algorithm. The result successfully mapped an ASGM footprints, estimating an area of 10,044.38 ha with 89.23% accuracy through Sentinel-1 data and an area of 12,308.57 ha with 87.25% accuracy through Sentinel-2 data. The spatial distribution of ASGM footprints is scattered over the streams and tributaries across all regions. These maps are pivotal in establishing regulatory measures for environmental restoration and preventing further expansion of degraded land.

Mercury pollution in the soil and river water of the Ratai watershed by artisanal and small-scale gold mining activities in Pesawaran District, Lampung, Indonesia

&lt;p&gt;The high risk of mercury pollution in the Ratai watershed due to artisanal and small-scale gold mine activities in Pesawaran District, Lampung, Indonesia, was evaluated. Studies are needed to improve the understanding of the effect of heavy metal pollution, especially mercury (Hg), in soil and river water along the watershed because of erosion. The Universal Soil Loss Equation (USLE) integrated with Geographic Information Systems (GIS) model was used to analyze the transport of mercury (Hg) from nonpoint source pollution loads to the Way Ratai River using rainfall-based erosion. Soils and river water samplings were conducted in 2020. Biophysical conditions, the land cover, and the rainfall data of the Ratai watershed were also taken into account. The results indicated that Hg concentrations in the soil and the river water were high, ranging from 0.26-28.9 mg L&lt;sup&gt;-1&lt;/sup&gt; and from 0.08-14.1 mg L&lt;sup&gt;-1&lt;/sup&gt;, respectively. The reason for the high Hg contents in the soils and the river waters was the high erosion rate in the watershed. As the study area was characterized by high rainfall erosivity and low to high soil erodibility, the erosion-caused Hg contamination in soil and water can be significant if no conservation strategies are developed.&lt;/p&gt;

GEOCHEMICAL AND MAGNETIC CHARACTERISTICS OF PLACER GOLD DEPOSITS FROM CENTRAL KALIMANTAN, INDONESIA

Massive tailings have resulted from the extensive use of placer deposits in Central Kalimantan, Indonesia, by artisanal and small-scale gold mining (ASGM) activities. Recently, the placer deposits and their tailings have been exploited for heavy minerals. In this study, geochemical and magnetic analyses were carried out on these deposits to identify the prospect of REE (rare earth element) exploration in the materials already collected by ASGM activities. Samples were collected from ten different locations. For each location, two different fractions were prepared for analyses, i.e. the heavy mineral (HM) fraction and the panned (M60) fraction. All HM and M60 samples were subjected to magnetic susceptibility measurements, but only representative samples were subjected to x-ray fluorescence (XRF) measurements (for Si, Ti, Fe, Zr, and Al) and to inductively coupled plasma-emission spectroscopy (ICP-OES) measurements (for Eu, Tb, Dy, and Sc). The results showed that the concentrations of major elements (Ti, Fe, Zr, and Al) vary significantly from deposits along one river to another, while the concentration of Si is rather similar. Compared to M60 samples, the HM samples have higher concentrations of Ti, Fe, Zr, Al, and Sc, implying that the sluice-box separation enhances the concentration of valuable minerals. Magnetic susceptibility is found to be correlated with Fe and Sc concentrations, confirming the potential use of magnetic measurements as a complementary tool for Fe and Sc exploitation in placer deposits. It is believed that both the source rocks and the sedimentary settings of these deposits determine whether certain elements (Sc, Fe, and Zr) are present or absent in Central Kalimantan placer deposits. The prospect of exploring and exploiting Sc in these placer deposits might augment the ASGM activities in Central Kalimantan.

Human exposure to mercury in the atmosphere and soils in Konongo: an age-old mining centre in the Ashanti Region of Ghana.

The dramatic upsurge of artisanal and small-scale gold mining (ASGM) activities in Ghana has resulted in environmental degradation, water pollution and human exposure to mercury-the main hazardous element used in gold extraction. This study evaluated the degree of human exposure to mercury based on the concentrations found in the air and soil samples taken at a resolution of 1 km2 across Konongo, a historic mining town in Ghana's Ashanti Region. The highest atmospheric mercury concentration was 193ng/m3, which is much higher than the levels the European Union and Japan allowed, which are 10ng/m3 and 40ng/m3, respectively. The concentration in the soil was 3.6mg Hg/kg, which is around ten times higher than the background concentration in nature. Additionally, the soil concentrations were higher above the worrisome levels of soil contamination in agricultural land (4mg/kg) and industrial areas (16mg/kg), respectively. Soils are extremely contaminated with mercury at sites artisanal mining activities take place. The concentrations of mercury in the air and soils were significantly higher (p < 0.5) at locations of prominent mining activities compared to areas not close to mining sites. The inhabitants of the Konongo community are therefore exposed to mercury, most likely emitted from artisanal mining activities. A non-carcinogenic risk is posed to the people by inhaling mercury vapour through the air and vapourisation from the soil. Children are exposed to a higher risk than adults as they receive higher daily doses of mercury than adults.