Small-scale Gold Mining Area Research Articles

Effectiveness of Different Sources of Biochar for Immobilizing Mercury in Soil from Artisanal and Small-Scale Gold Mining Areas in Taliwang Village of West Sumbawa Regency, Indonesia

Effectiveness of Different Sources of Biochar for Immobilizing Mercury in Soil from Artisanal and Small-Scale Gold Mining Areas in Taliwang Village of West Sumbawa Regency, Indonesia

Mercury Contamination from Artisanal Small-scale Gold Mining Activities in Simpenan District, Sukabumi Regency, West Java, Indonesia

Mercury is still used in the amalgamation process in small-scale gold processing. This study aims to evaluate the mercury contamination of various environmental media in the artisanal small-scale gold mining (ASGM) area in the Simpenan District, Sukabumi Regency. The ecological media examined in this study included groundwater, river water, soil, sediment, biota, and plants. The threshold number was determined using APHA 3125 and Indonesian National Standard (SNI) 7387:2009. Meanwhile, the mercury concentration in the ambient air was measured directly using a mercury analyser. Mercury concentrations in the water, soil, sediment, biota, and plant matrices were calculated using a calibration curve. The study found that the levels of mercury in groundwater, river water, and sediment were all below the applicable quality standards of <0.0001, <0.0001 and 0.001 mg/L, respectively. However, the levels of mercury in soil and plants were 27.28 and 0.52 mg/kg, respectively. Additionally, the levels of mercury in four types of fish found in a river adjacent to the ASGM location, namely beunteur (0.33 mg/kg), snakehead (0.05 mg/kg), catfish (0.26 mg/kg) and eel (0.20 mg/kg), exceeded the specified quality standards. In conclusion, mercury contamination is present in the soil, plants, and aquatic biota (fish) in the ASGM area in the Simpenan District, Sukabumi Regency.

Health and environmental risk assessment of mercury in outdoor and indoor dust in artisanal and small-scale gold mining area in Amansie-west district in the Ashanti Region of Ghana.

Mercury (Hg) pollution around artisanal and small-scale gold mining (ASGM) areas has been of much concern. Many studies have reported elevated Hg concentrations in environmental media, but studies on dust relating to inhalation exposure of Hg around ASGM area are limited. In this study, we investigated Hg in indoor and outdoor dust to reveal environmental and human health risk around ASGM in Amansie West district, Ghana. Indoor and outdoor dust samples were collected from Manso Abore and Manso Nkwanta in Ashanti Region. Concentration of Hg in the samples were analyzed using a direct Hg analyzer. The mean and median value of Hg concentration in the indoor dust (n = 31) were 2.2 ± 3.6mg/kg and 0.72mg/kg respectively while that of the outdoor dust (n = 60) were 0.19 ± 0.48mg/kg and 0.042mg/kg, respectively. The mean and median Hg concentration in indoor dust were about 11 and 17 times higher respectively than that in the outdoor dust. The Hg concentration in the indoor dust was statistically significantly higher than that of the non-miner in Manso Abore (p < 0.05) but was not significant in Manso Nkwanta, probably due to higher mining activity. The geo-accumulation index of the outdoor dust ranged from unpolluted to extremely polluted while that of the indoor dust ranged from moderately polluted to extremely polluted. Health risk assessments suggested that there was no potential non-carcinogenic health effect for Hg exposure relating to the dust to residents living in rooms of miners and non-miners.

The capacity of Plectranthus sp. to perform phytoremediation on heavy metal mercury (Hg) in the tailing of gold processing industries

Sludge (tailing), a waste product of the amalgamation process used in the mining of gold, contains a high concentration of the heavy metal mercury (Hg). It is well known that mercury builds up in large quantities in Plectranthus sp. herbaceous plants in the Pancurendang Village Small-Scale Gold Mining area. The study intends to: 1) quantify the amounts of mercury present in plant organs and media tailing during phytoremediation treatment; 2) examine the mechanisms and capacities of plant phytoremediation using values of the Biological Accumulation Coefficient (BAC), Biological Concentration Factor (BCF), and Translocation Factor (TF); and 3) determine the impact of percentage variations in tailing and time on Plectranthus sp.’s capacity to accumulate mercury. On a lab scale, phytoremediation of tailings is done with concentrations of 0%, 30%, 50%, and 100%. Planting medium is combined with dried tailings. Pots are used for phytoremediation, and the residence times are 10, 20, and 30 days. With the use of a mercury analyzer, the amount of mercury present in plant media, roots, and shoots is determined. Using the BAC, BCF, and TF values, the mathematical calculation of phytoremediation ability is performed. Hg content ranged from 1.82 to 16.23 ppm in shoots and 5.15 to 37.19 ppm in roots. Throughout the course of treatment, the tailings Hg concentration varied between 13.18 and 220.05 ppm. Plectranthus sp. is categorized as a medium accumulator with a phytoextraction mechanism, according to the analysis’s findings. Hg phytomining is possible with Plectranthus sp., the TF value is 2.38. Within 10 days, Plectranthus sp. most effectively accumulates 50% Hg in tailings.

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.

Mercury Accumulation in Food Crops and Phytoremediation Potential of Wild Plants Thriving in Artisanal and Small-Scale Gold Mining Areas in Uganda

Mercury (Hg) has been used for millennia in artisanal and small-scale gold mining (ASGM) to extract gold from ore as an amalgam that is heated to recover gold. Since there is hardly any sustainable technology that can be used to recover it, the vast percentage of released Hg finds its way into the environment. Currently, ASGM is the largest source of mercury pollution on Earth. Mercury (Hg) is listed among the top 10 most harmful metals by the World Health Organization (WHO), and it is known to cause several neurological disorders in humans. Thus, Hg levels in environmental systems surrounding pollution hotspots such as ASGM mines need to be monitored to ensure their proper management and protect vulnerable ecosystems and human health. This work was aimed to study the level of Hg pollution in soils and plants thriving around ASGM mines in Eastern Uganda and to evaluate the Hg phytoremediation potential of the plants. The total Hg contents were determined for soils, food crops and wild plants growing around ASGM mines. The results for the pH, organic carbon (OC) and electric conductivity (EC) of the soils in the study area were comparable to those of the control soils. The soils in the studied ASGM areas exhibited high Hg concentrations ranging between 723 and 2067 folds more than those of the control soils. All soils were moderately to heavily contaminated according to geoaccumulation (Igeo) index values that ranged between 1.16 and 3.31. The results of this study also showed that the food crops and wild plants accumulated Hg levels that were above the 20 ng/g (0.02 ppm) permissible limit. This study revealed relatively higher levels of Hg in the aerial parts of the plants compared with the underground organs, which can be attributed to Hg deposition, entry through stomata and foliar adsorption. Mercury levels in 47% of the food crop samples were above the FAO/WHO permissible mercury limit of 0.5 µg/g. Similarly, medicinal plants accumulated Hg to levels that were several folds higher than the 0.2 ppm permissible limit of mercury in herbal materials of Canada. Interestingly, this study showed that some wild plant species, especially sedges, exhibited relatively higher levels of mercury accumulation than others thriving in the same environment, an indication that such plants could be utilized in the phytoremediation of Hg-contaminated sites.

IDENTIFICATION OF MERCURY CONTENT AMONG CHILDREN WITH STUNTING AGED 25 - 59 MONTHS IN THE SMALL-SCALE GOLD MINING AREA OF KRUENG SABEE SUB-DISTRICT, ACEH JAYA REGENCY

This study investigates the hazardous impact of mercury, classified as a Category B3 heavy metal waste, on human life and the environment. It focuses on the significant contribution of artisanal mining to mercury pollution and its adverse effects on the landscape. In particular, the research examines the health risks posed by mercury exposure to children living in Peri-Urban Artisanal and Small-Scale Gold Mining (PESK) areas, including compromised immune responses and the potential for stunting. Urine samples were collected from participants using purposive sampling in accordance with Minister of Health Regulation No. 43/2013 and analyzed using Atomic Absorption Spectroscopy (AAS). All ten samples exhibited the presence of mercury, with one falling below the 7 μg/L threshold established by Human Biomonitoring (HBM) guidelines. Notably, the study found that 99% of stunted toddlers exceeded the mercury threshold, while only 0.1% remained below it. This research contributes to a deeper understanding of the health and environmental implications associated with mercury contamination.

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.

Geochemistry of Potentially Toxic Elements in Soil and Sediments of a Tanzanian Small-Scale Gold Mining Area

Geochemistry of Potentially Toxic Elements in Soil and Sediments of a Tanzanian Small-Scale Gold Mining Area

The dynamics of mercury around an artisanal and small-scale gold mining area, Camarines Norte, Philippines.

To elucidate the dynamics of mercury emitted and released by artisanal and small-scale gold mining (ASGM) activity and to estimate its impact on the ecosystems of the bay, the distribution of mercury in the atmosphere, soil, water, and sediment around Mambulao Bay, Camarines Norte, Philippines, was investigated. The ASGM operations use mercury to extract gold from ore and are located on the east shore side of the bay. Samplings were conducted in August 2017 and September 2018. The samples were used for determination of total mercury (T-Hg) and organic mercury (org-Hg) concentrations, total organic carbon (TOC) content, and chemical composition. The atmospheric mercury concentration on the east shore side, 6.1-25.8ngm-3, was significantly higher than the value of 1.4-9.9ngm-3 observed on the west shore side. The average concentrations of T-Hg in the forest soils of the west shore side and those of the east shore side were 0.081 ± 0.028mgkg-1 and 0.496 ± 0.439mgkg-1, respectively. In the vertical distribution of T-Hg in the soil of the east shore side, a higher concentration was observed near the surface. For the vertical variations in T-Hg in the marine sediment, higher values were observed near the estuary, and the vertical variations in core samples showed an increase in mercury concentration toward the surface. The highest concentration of T-Hg in sediment, 9.5mgkg-1, which was 2 orders of magnitude higher than the background levels of this area, was found near the river mouth. The T-Hg, org-Hg, and TOC levels showed a positive correlation, suggesting that the rivers are the main sources of T-Hg and org-Hg in the bay. Although the fish sample containing a mercury content higher than the regulatory level for fish and shellfish of 0.4mgkg-1 in Japan was only one of 42 samples, the percentage of org-Hg in fish samples was 91 ± 18%. Mercury released into the surroundings by the ASGM activities can be converted into methylmercury and affect the bay's ecosystem.

Assessment of blood mercury, immune response, heat shock and oxidative stress marker in free-ranging chicken (Gallus Gallus domesticus) from gold mining areas in Zamfara State, Nigeria

We investigated serum mercury, immune response, heat shock and oxidative stress marker in free-ranging chicken (Gallus Gallus domesticus) from Artisanal and small-scale gold mining (ASGM) areas. Six groups were created from sixty free-ranging chickens (Gallus Gallus domesticus), three each from ASGM and non-ASGM areas. Immune response, heat shock and oxidative stress markers were analysed, and multivariate and univariate data analysis were used to discriminate the difference in the study group. Results revealed a significant increase in serum mercury (Hg) from chicken in ASGM areas. Superoxide dismutase, glutathione peroxidase (GPx), glutathione (GSH), catalase and total antioxidant capacity significantly decreased, while lactic acid dehydrogenase and malondialdehyde (MDA) content significantly increased in animals from ASGM areas. A unit increase in GPx and GSH significantly corresponds to a decrease in serum Hg by 0.001 μg/mL and 0.206 μg/mL, respectively. While a unit increase in MDA significantly corresponds to an increase in serum Hg level by 0.003 μg/mL. The activities of HSP-70, TNF-α, IL-1β and IL-6 were significantly higher in the serum of chicken from ASGM areas. All significance at p < 0.05. ASGM activities result in mercury bioaccumulation with potential health effects caused by dysregulated immunity, heat shock and oxidative stress.

Validation of Mercury Speciation Analysis in River Around Artisanal Small-Scale Gold Mining Area in West Nusa Tenggara, Indonesia

A method for determining mercury concentration using a mercury analyzer in a river water sample was validated according to ISO/IEC 17025. Analytical performance including linear range, limit of detection, precision and accuracy were evaluated. Mercury speciation profile was obtained from Pelangan River at three areas within Dusun Rambut Petung, an area with the highest amount of artisanal small-scale gold mining (ASGM) in Lombok, West Nusa Tenggara. Then, their concentration in each species was measured using sequential extraction. Good curve linearity was obtained in the concentration range of 0.1-5.0 µg/L and the limit of detection was 0.014 µg/L. The developed method has good precision and accuracy with a RSD value &lt;10% and a recovery of 94.16-101.91%. The detected fraction of mercury in the Pelangan river is organomercury, elemental mercury, and sulfide-bound species with each concentration of 0.732±0.032; 0.350±0.027; and 0.850±0.027 µg/L, respectively. The measurement results showed conformity with the reference method using CV-AAS. Therefore, this method can be applied to determine mercury levels in water for monitoring environmental quality.

Contamination Level in Geo-Accumulation Index of River Sediments at Artisanal and Small-Scale Gold Mining Area in Gorontalo Province, Indonesia.

Substances found in watersheds and sediments in artisanal and small-scale gold mining (ASGM) areas contaminated by heavy metals are becoming tremendously critical issues in Asia. This study aimed at clarifying the pollution caused by heavy metals in sediments in river basins near ASGM sites in Gorontalo Province, North Sulawesi, Indonesia. Sediment samples collected from experimental areas were classified into nine clay samples and twenty-seven sand samples, whereas three other samples were collected from the control area. Particle-induced X-ray emission was used to analyze these samples. The Statistical Package for the Social Science and the geo-accumulation index (Igeo) were also used for analysis. Based on the results, Hg, Pb, As, and Zn had a concentration of 0–334 µg/g, 5.5–1930 µg/g, 0–18,900 µg/g, and 0–4923.2 µg/g, respectively, which exceeded limits recommended by the U.S. Environmental Protection Agency consensus (1991) and the Indonesian Government Regulation Number 38, 2011. Furthermore, Igeo showed the order of the pollution degree Hg < Zn < Pb < As and reflected an environment contaminated by heavy metals, ranging from unpolluted to extremely polluted areas. Therefore, sediments contaminated by Hg, Pb, As, and Zn could be found along the river basin of mining areas.

Atmospheric Hg Levels in Tree Barks Due to Artisanal Small-Scale Gold Mining Activity in Bunut Seberang Village in Indonesia

Mercury (Hg) is a useful heavy metal; however, it is toxic to both humans and the environment. Tree bark is an excellent bioindicator, which has been proven to be effective in studying the level of atmospheric Hg contamination. This study aimed to determine the distribution of evaporated Hg using the total weight of Hg (THg) in tree barks in Indonesia at the artisanal and small-scale gold mining (ASGM) area of Bunut Seberang Village and Lampung University, respectively. Samples were taken using purposive sampling, based on the criteria of forestry trees at a height level of 1.3 m above ground as wide as 100 cm2. The samples were analyzed by atomic absorption spectrometry and Scanning electron microscopy to determine the levels of THg and to investigate the bark structures. Results showed that the highest THg values were found in a Magnolia champaca sample (56.5 µg), followed by Swietenia mahagoni (45.8 µg) and Swietenia mahagoni (33.5 µg). All species studied showed THg levels in the tree barks at an elevation from 30 to 320 m above sea level. The Hg amounts found in the sampled barks indicated the dispersion of Hg throughout the ASGM area, which signified hazardous atmospheric conditions in the area.

Evaluation of the Total Mercury Weight Exposure Distribution Using Tree Bark Analysis in an Artisanal and Small-Scale Gold Mining Area, North Gorontalo Regency, Gorontalo Province, Indonesia.

It is well known that atmospheric mercury (Hg) contaminates air, water, soil, and living organisms, including trees. Therefore, tree bark can be used for the environmental assessment of atmospheric contamination because it absorbs heavy metals. This study aimed to establish a new biomonitoring for the assessment of atmospheric Hg pollution. Reporting on atmospheric Hg contamination in an artisanal and small-scale gold mining (ASGM) area in North Gorontalo, Indonesia, we calculated the total weight of Hg (THg) and quantitatively measured the concentrations of Hg in the tree bark of Mangifera indica, Syzygium aromaticum, Terminalia catappa, and Lansium domesticum. The THg of Hg in the M. indica tree bark samples ranged from not detected (ND) to 74.6 μg dry weight (DW) per sample. The total Hg in the tree bark of S. aromaticum, T. catappa, and L. domesticum ranged from ND to 156.8, ND to 180, and ND to 63.4 μg DW, respectively. We concluded that topography significantly influences the accumulation of Hg together with local weather conditions. A mapped distribution of the THg suggested that the distribution of THg in the tree bark was not affected by the distance to the amalgamation site. Therefore, tree bark can be used as biomonitoring of atmospheric Hg contamination for the assessment of ASGM areas.

Element Rich Area Associated with Human Health Disorders: A Geomedical Science Approach to Potentially Toxic Elements Contamination.

(1) Background: Geomedical science focuses on the relationship between environmental impact and human health. The abundance of elements in a geographic area is reflected accumulation of these elements in humans. This study aims to describe the relationship between concentrations of geologic elements and accumulations in the human body as well as element-related symptoms. (2) Methods: Geogenic sampling was conducted in an Artisanal and Small-Scale Gold Mining (ASGM) area and around residential areas in Indonesia, and samples were analyzed using particle-induced X-ray Emission (PIXE). Head hair was sampled, and health assessments were performed to determine heavy metal exposure, especially to copper and mercury. (3) Results: Results show that potentially toxic elements’ accumulation in the human body follows the abundance of these elements in the geographic area, which then affect health and manifest with specific signs and symptoms. East Tulabolo is an area rich in copper (hazard quotient (HQ) in dust = 152.8), and most of the population shows the sign of Kayser–Fleischer rings. Likewise, the Dunggilata area has the highest concentration of mercury, especially in the dust (HQ = 11.1), related to ASGM activity in residential areas. (4) Conclusions: This study concludes that the geogenic concentration of elements parallels the accumulation of human tissue and manifests with element-related signs and symptoms.

Characterization of potential mercury contamination in the ASGM area of Mandailing Natal, North Sumatera

A large amount of Hg is used for gold extraction through the amalgamation process in the Mandailing Natal derived from artisanal and small-scale gold mining (ASGM) area located in the North Sumatera Province, Indonesia. The objective of this work was to characterize the potential contamination of total Hg in water, sediments, and soil in this ASGM area. Sampling was done in two locations in West Panyabungan and Huta Bargot Districts using grab sampling method. Results showed that accumulation of Hg in the studied soils and sediments was the highest, but Hg in aquatic solution was below the detection limit of the analytical method of the studied community wells and rivers. The highest concentration of Hg was found in the river sediments of the Saba Padang irrigation (1,63 mg/kg), and in the soil of the plantation area of Huta Bargot (1,62 mg/kg) respectively. These concentrations may pose a serious problem for aquatic and land life, related ecosystems, and human health. For further study, there is a need to study Hg availability in riverine biota to better understand the cycling of Hg in this ASGM area. Understanding the ecological impacts can assist in the prioritizing of impact mitigation efforts.

Biomonitoring of arsenic, cadmium and lead in two artisanal and small-scale gold mining areas in Zimbabwe

People living and working in artisanal and small-scale gold mining (ASGM) areas are frequently exposed to elemental mercury (Hg), which is used for gold extraction. However, additional exposure to other toxic metals such as arsenic (As), cadmium (Cd) and lead (Pb) may result from mining-related activities and could be ingested via dust, water or food. In these areas, only limited biomonitoring data is available for toxic metals other than Hg. In particular, data about the exposure to As, Cd and Pb is unavailable for the Zimbabwean population. Therefore, we conducted a cross-sectional study in two ASGM areas in Zimbabwe to evaluate the internal exposure to these metals. In total, urine and blood samples from 207 people that identified themselves as miners were collected and analysed for As and Cd in urine as well as Pb in blood by GF-AAS. Median levels (interquartile ranges in μg/l) of As and Pb were 9.7 μg/l (4.0, 18.5) and 19.7 μg/l (12.5, 34.5), respectively. The 25th percentile and the median for Cd were below the limit of detection (0.5 μg/l); the 75th percentile was at 0.9 μg/l. The results were compared to reference values found for the general population in the USA and Germany, and a significant number of participants exceeded these values (As, 33 %; Cd, 27 %; Pb, 32 %), indicating a relevant exposure to toxic metals. Although not representative for the Zimbabwean population, our results demonstrate that the exposure to toxic metals is relevant for the public health in Zimbabwe and requires further investigation.

Analysis of the Mercury Distribution in Blood as a Potential Tool for Exposure Assessment \u2014 Results from Two Artisanal and Small-Scale Gold Mining Areas in Zimbabwe

People in artisanal and small-scale gold mining (ASGM) areas are frequently exposed to high levels of mercury (Hg). Hg analyses in urine and whole blood are the gold standard of biomonitoring, although this may not provide sufficient information about the source of exposure, e.g., due to the use of Hg for gold extraction or due to nutrition. To evaluate, whether the pharmacokinetic properties of individual Hg species may be useful for exposure assessment, we determined the Hg levels in different blood components from 199 participants. Therefore, whole blood was centrifuged on-site to yield erythrocytes and plasma. Globin was isolated from the erythrocytes by precipitation with ethyl acetate. Albumin was isolated from plasma by gradual precipitation with saturated ammonium sulfate solution. Hg levels in all samples were determined by using a direct Hg analyzer. Median Hg levels for whole blood, erythrocytes, and plasma were 2.7, 3.7, and 1.3 μg/l, respectively. In globin and albumin, median Hg levels were 10.3 and 7.9 μg/kg, respectively. The distribution of Hg was strongly correlated with whole blood Hg levels (p < 0.01) and the time between the last use of Hg and the date of the participation (p < 0.01). The results suggest that the distribution of Hg in blood is substantially affected by the extent and the frequency of the exposure to elemental Hg. Therefore, the analysis of Hg in erythrocytes and plasma may be a valuable tool for Hg exposure assessment in ASGM areas.

Potential bacteria capable of remediating mercury contaminated soils

Mercury content in ex-artisanal and small-scale gold mining areas in Cianjur District, Province of West Java, Indonesia was 7 to 36 mg L−1. It has exceeded the threshold value for industrial land. Bioremediation of mercury using mercury-resistant bacteria is attractive to remove mercury from the environment because it is more effective and less expensive. The objective of this study was to obtain potential bacteria capable of accumulating mercury to be used to remediate mercury contaminated soils in ex-gold mining areas. Potential bacteria isolates were characterized for their phenotypic and biochemical properties using the Biolog system. Thirty-two mercury-resistant bacteria were successfully isolated from the rhizosphere of Pityrogramma tartarea growing predominantly around tailings of ex-artisanal gold mining. After screening the presence of mercury, the three best isolates showing high resistances are Pseudomonas putida R2.13 and P. maculicola R4.27 that are capable to tolerate 180 mg L−1 mercury, and Enterobacter aerogenes R3.24 that is capable to survive at 170 mg L−1. Furthermore, the three bacteria also can fix atmospheric nitrogen and solubilize phosphate, but they cannot solubilize potassium. These indicate that P. maculicola R4.27, P. putida R2.13, and E. aerogenes R3.24 are potential as bioaccumulation agents on mercury-contaminated soils.