Small-scale Gold Mining Activities Research Articles

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.

Resilience Capability of Indigenous People Affected by Small-Scale Gold Mining Activities: A Prevention Approach

This research addresses three main review points related to the harmful practices of artisanal and small-scale gold mining and the appropriateness of prevention approaches to resilience for local residents’ environments. First, the focus is on cases of illegal mining exploitation in North Rarowatu and Lantari Jaya, with emphasis on the aspects of disaster risk management and prevention approaches in construction areas. Second, focus is given to the abundance of gold grains in the mining area, which attracts the author to utilize a dynamic system approach to explore whether a progressive restructuring exists for avoiding casualties in the mining area. Third, the precautionary accuracy of the security forces and the government are given focus to emphasize the prohibition of mercury absorption as a mining method. This research utilizes a system dynamics methodology to investigate the review of preventive approaches for maintaining the resilience of local communities and the determinants of small-scale gold mining activities by considering other empirical testing models. This study finds that a 30–50% increase in gold production significantly results in hydrological pollution due to mercury content, increased worker deaths, and unending damage to resident ecosystems, with minimal preventive capabilities in the pre-illegal artisanal and small-scale gold mining period. Moreover, this study offers an input and output prevention approach to controlling the number of illegal gold miners while protecting the environmental resilience of local residents.

Determination of mercury in soil and water from a gold mining area in Karang Jaya Sub-district, Musi Rawas Utara, Indonesia

The present study focuses on the assessment of Hg distribution in both soil and water samples from the small-scale gold mining region of Karang Jaya Sub-district, Musi Rawas Utara Regency, South Sumatra Province. For over 30 years, this region has witnessed persistent utilization of mercury as an amalgam for gold extraction. The investigation encompasses an analysis of total mercury levels in soil samples obtained from Sukamenang, Muara Batang Empu, and Terusan Villages. As a comparative reference point devoid of gold mining activities, the neighboring Muara Lakitan Village was selected. The obtained results indicate a moderate to strong contamination level across the 30 sampled locations based on the Geoaccumulation Index (Igeo), with an average Igeo value of 2.6. Furthermore, Pollution Load Index (PLI) and Contamination Factor (CF) values demonstrate high contamination. Conversely, analysis of river water samples from 30 stations along the Rupit River reveals that most of the samples comply with quality standards (<0.0005 mg/L), with an average value at 0.000322 mg/L; only four stations exhibit total Hg concentrations surpassing regulatory thresholds. All soil and river water samples from the control area (10 stations) exhibited no signs of pollution. Appropriate investments in technology, finance, and technical skills are needed to reduce mercury pollution due to small-scale gold mining activities.

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.

The Socio-cultural Determinants of Child Labour in Tanzania

The purpose of the study was to examine the socio-cultural determinants of child labour in small scale gold mining in Tanzania. Specifically, the study examined polygamy, early marriage and family conflict among the respondents which influence child labour practices in small scale gold mining (SSGM) in Geita region. Furthermore, the study used the case of Nyang’hwale district which is one of the districts in Geita region where SSGM activities are rampant compared to the rest of the districts. The study used a cross-sectional survey researches design. The primary data were collected by using questionnaires from 209 individuals who were randomly sampled from Nyang’hwale district in Geita region. Moreover, the study applied a newly developed method of measuring the age risk of children working under 18 years known as Eta Value. The researcher analyzed the data using the Structural Equation Modeling Partial Least Square (SEM PLS) with a combination of analytic techniques - statistics and artificial intelligence software. The study found that the child labour determinants under socio-cultural factors were polygamy, early marriage and family conflict. Moreover, the researcher found that micro-sociology focuses on the individual's micro aspects – polygamy, early marriage and family conflicts which are socio-cultural oriented. The study concludes that the fundamental sociocultural determinants are polygamy, early marriage and family conflict. Therefore the study recommends that the polygamy, early marriage and family conflict are significant sociocultural factors that contribute to the child labour practices in Geita.

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.

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.

Why is Ghana losing the war against illegal gold mining (Galamsey)? An artificial neural network-based investigations.

Ghana, like most resource-rich countries, is saddled and inundated with resource curse challenges. Key among them is the problem of illegal small-scale gold mining activities (ISSGMAs), which is mercilessly robbing the nation of its ecological integrity, despite attempts by successive governments to remedy the situation. In the midst of this challenge, Ghana, year in and year out, performs abysmally on environmental governance score (EGC) variables. Against this framework, this study intends to uniquely establish the drivers behind Ghana's failure to overcome ISSGMAs. To achieve this, a total of 350 respondents were sampled through a structured questionnaire, with a mixed method approach from selected host communities, believed to be the epicenters of ISSGMAs in Ghana. The questionnaires were administered from March to August, 2023. AMOS Graphics and IBM SPSS vs 23 were used to analyze the data. In particular, the novel hybrid artificial neural network (ANN) and linear regression techniques were adopted to establish the relational linkages among the constructs of the study and their respective contribution to ISSGMAs in Ghana. The study displays intriguing results that explain why Ghana has failed to be victorious over ISSGMAs. In particular, the findings of the study demonstrate that the three key drivers of ISSGMAs in Ghana, in a sequential and consecutive order are as follows: bureaucratic licensing regime/weak legal framework, political/traditional leadership failures, and corrupt institutional officials. Moreover, socioeconomic factors and proliferation of foreign miners/mining equipment were also observed to contribute significantly to ISSGMAs. While the study contributes to the ongoing debate on ISSGMAs, it also proffers valuable and practical solutions to the menace as well as theoretical implications.

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.

Analisis Longitudinal Struktur Komunitas Makrozoobentos yang Tercemar Limbah Pertambangan Emas Skala Kecil di Sungai Cikondang, Jawa Barat

Small-scale gold mining activities are still mostly carried out in various regions in Indonesia. The use of mercury (Hg) in the process of extracting gold from sediments can be a source of pollution for aquatic ecosystems and organisms. The aim of this study was to analyze the macrozoobenthos community structure in the Cikondang River which was affected by Hg pollution due to small-scale gold mining. Sampling was carried out by survey method at 5 sampling points along the Cikondang River from upstream to downstream. Water quality parameters measured include temperature, transparency, current velocity, pH, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Hg concentrations in sediments and macrozoobenthos were measured using automatic mercury analyzer. The results showed that the concentration of Hg in sediments in the Cikondang River ranged from 0.63–52.48 mg/kg and the accumulation of Hg in macrozoobenthos ranged from 0.97 to 0.98. The macrozoobenthos diversity index was 1.50-2.17 and the dominance index was 0.16-0.30. The most group of macrozoobenthos found was from the Gastropod class, followed by the Insecta and Malacostraca classes. Macrozoobenthos in the Cikondang River were only found in the downstream of the river, at Sampling Points 4 and 5 only. This showed that Hg pollution in the Cikondang river is highly toxic, caused macrozoobenthos was not found at Sampling Point 1, 2 and 3.

Ecological aspects shaping child labour in Tanzania's artisanal and small-scale gold mines: A qualitative inquiry

BackgroundThis study describes factors promoting child labour in small-scale gold mines in rural Tanzania, a pernicious problem despite the country's adoption of laws and regulations intended to curb it. MethodsEmploying a phenomenological design, we collected qualitative data using focus group discussions and in-depth interviews to describe factors promoting children's engagement in small-scale gold mining activities in three districts in Tanzania. Data analysis applied constructs from the ecological system theory. ResultsChild labour was reported to be common in the small-scale gold mines and abject household poverty was reported as the main factor pushing children to work in the mines because of their respective households’ inability to provide for their basic needs. Other underlying factors stated included divorce and family disintegration and limited diversification of income-earning activities. The migratory nature of artisanal mining led some miner parents to not prioritize the education of their children. Furthermore, peer pressure and parental influence, especially of mothers, promoted entry into mining or reinforced its continuation. Early socialisation of children as future miners and lack of perspective and societal expectations of other life trajectories contributed to persistent child labour within mining communities. At the government level, the study participants mentioned poor reinforcement of mining regulations as another factor that legitimised child labour in the mines. ConclusionSince factors promoting child labour in small-scale gold mines are multifaceted, efforts for its elimination require a multi-layered approach aimed at addressing the root-causes at the micro-, meso-, exo- and macro-level systems.

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

Generalist arbuscular mycorrhizal fungi dominated heavy metal polluted soils at two artisanal and small − scale gold mining sites in southeastern Ecuador

BackgroundArtisanal and small-scale gold mining activities are producing contamination with heavy metals and metalloids (HMM) into soils and water worldwide. The HMM are considered as one of the major abiotic stresses due to their long-term persistence in soil. In this context, arbuscular mycorrhizal fungi (AMF) confer resistance to a variety of abiotic plant stressors including HMM. However, little is known regarding the diversity and composition of AMF communities in heavy metal polluted sites in Ecuador.MethodsIn order to investigate the AMF diversity, root samples and associated soil of six plant species were collected from two sites polluted by heavy metals, located in Zamora-Chinchipe province, Ecuador. The AMF 18S nrDNA genetic region was analyzed and sequenced, and fungal OTUs were defined based on 99% sequence similarity. Results were contrasted with AMF communities from a natural forest and from reforestation sites located in the same province and with available sequences in GenBank.ResultsThe main pollutants in soils were Pb, Zn, Hg, Cd and Cu with concentrations exceeding the soil reference value for agricultural use. Molecular phylogeny and OTU delimitation showed 19 OTUs, the family Glomeraceae was the most OTU-rich followed by Archaeosporaceae, Acaulosporaceae, Ambisporaceae and Paraglomeraceae. Most of the OTUs (11 of 19) have been found at other locations worldwide, 14 OTUs were proven from nearby non-contaminated sites in Zamora-Chinchipe.ConclusionOur study showed that there are no specialized OTUs at the studied HMM polluted sites, but rather generalists adapted to a wide variety of habitats. Their potential role in phytoremediation approaches remains to be investigated.

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;

Assessment and bioremediation of mercury pollutants by highly mercury-resistant bacteria immobilized in biochar from small-scale artisanal gold mining areas

Small-scale gold mining activities in Indonesia still use amalgamation techniques, which have the potential to cause mercury (Hg) pollution and affect the quality and number of microorganisms. Mercury-resistant bacteria can survive and adapt to mercury-exposed environments and can be developed as bioremediation agents. The bioremediation activity of these bacteria can be increased through immobilization using biochar. The results of observations of physicochemical qualities in three samples in the mining area, showed significant differences. The TOC in the rhizosphere soil sample of &lt;em&gt;Calliandra calothyrsus&lt;/em&gt; L. showed the significantly highest value at 14.5%, and the pH of the three samples indicated acidity and exhibited no difference (p&amp;lt;0.05). The highest concentration measured in the tailing sample was 9.9 ng/g (p&amp;lt;0.05). The number of heterotrophic bacteria in the rhizosphere soil was the highest at 7.2 × 10&lt;sup&gt;8&lt;/sup&gt; CFU/g. On the other hand, the number of mercury-resistant bacteria in the tailing sample showed the highest value of 6.3 × 10&lt;sup&gt;3&lt;/sup&gt; CFU/g. In the selection based on the toxicity profile of 30 mercury-resistant bacteria obtained, the highest results were observed in the LMP1B5 bacterial isolate from the river sediment, with 50% effective concentration (EC50) and minimum inhibitory concentration (MIC) values of 225 and 250 mg/L, respectively. Polyphasic identification based on phenotypic and genotypic characteristics using the 16S rRNA gene showed that the bacterial isolate was identified as &lt;em&gt;Escherichia fergusonii&lt;/em&gt;. The growth and mercury removal activity of &lt;em&gt;E. fergusonii&lt;/em&gt; LMP1B5 increased by 21% and 52%, respectively, after the immobilization with biochar. Thus, immobilized &lt;em&gt;E&lt;/em&gt;.&lt;em&gt; fergusonii&lt;/em&gt; LMP1B5 was effective in removing mercury pollutants.

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.