Global Burden of Disease of Mercury Used in Artisanal Small-Scale Gold Mining

L-cysteine mediated rapid separation of Hg2+ and MeHg+ by anion-exchange HPLC

Owing to the on-going emission of Hg into the global environment, new insight into their bioinorganic chemistry in mammals is urgently required to better understand their adverse health effects and analytical methods to quantify Hg2+ and MeHg+ in environmental samples are needed. Analytical separations can help to address both of these needs. While Hg2+ and MeHg+ have been most frequently separated by cation and reversed-phase (RP) HPLC, we here report on using anion-exchange (AEX) HPLC in conjunction with a flame atomic absorption spectrometer (FAAS) to observe the retention behavior of these mercury species in the pH range 5.0-8.0 using mobile phases comprised of 10 mM l-cysteine (Cys) in 100 mM phosphate buffer. The results obtained for pH 5.0 served as a starting point to develop a rapid HPLC separation for these mercurials. The addition of 5-20 % methanol (MeOH) to this mobile phase revealed that MeOH did not appreciably change the retention of Hg2+, but significantly reduced the retention of MeHg+. A 15 % MeOH-containing mobile phase offered the best compromise between achieving a rapid baseline separation in <400 s at affordable costs. To assess the suitability and robustness of the developed AEX-HPLC separation method for the analysis of environmental samples an inductively coupled plasma atomic emission spectrometer (ICP-AES) was employed as the mercury-specific detector. The developed AEX-HPLC-ICP-AES method allowed to achieve detection limits of 1.5 ppm for Hg2+ and 2.9 ppm for MeHg+ and was successfully applied to analyze wastewater that had been spiked with Hg2+ and MeHg+.

The impact of gold mining activities: understanding the dynamics of cyanide in river ecosystems in Ecuador

Understanding the behavior of cyanide in rivers is of utmost importance as it has a direct impact on the health of people who depend on these water sources. Cyanide contamination from gold mining activities poses a significant environmental threat to river ecosystems, particularly in southern Ecuador. This study aimed to investigate the behavior of cyanide when it enters contact with other metals in these rivers. Simulations were conducted to determine the speciation of cyanide, mercury, arsenic, lead, and manganese in a study area, taking into account the water temperature and pH at four locations. The findings revealed that CN-and HCN(aq) species were present in the research area. Additionally, mercury-cyanide (Hg(CN)2(aq), Hg(CN)3-), and manganese-cyanide (MnCN+) complexes were identified 3 km downriver from the site where the mining activity is higher. These metal-cyanide complexes tend to dissociate quickly under weak acidic conditions, making them hazardous to the environment. This research is crucial, not only for the environment but also for human health, as it allows to predict toxicity risks for people supplied with this water source, emphasizing the potential harm to human health. This study highlights the importance of stringent regulations and effective monitoring practices to mitigate cyanide contamination and safeguard environmental and occupational health.

Toxic potential evaluation of liquid effluents discharged into nature by the university hospital centers (UHC) and mixed wastewater treatment station (WWTS) at Ouagadougou-Burkina Faso

In Burkina Faso, several investigations have raised suspicions that hospital liquid effluents are the source of contaminants in porbeagle-culture products and surface water in urban and peri-urban areas. This study aimed to evaluate the hygienic quality of hospital liquid effluents discharged into nature by the UHC Bogodogo (UHC-BOG), Yalgado Ouédraogo (UHC-YO), and the WWTS of Kossodo (WWTS-KOS). Thus, 15 samples of liquid effluents (five per site) discharged into nature were collected. Within the physicochemical parameters, the pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solids (TSS), conductivity, copper, iron, hafnium, silver, mercury, lead, and cadmium of these samples were determined using standard methods. The mean values of pH were 8.84 ± 0.42,8.06 ± 0.54, and 8.55 ± 0.53 for WWTS-KOS, UHC-BOG, and UHC-YO, respectively. Conductivity values were 1956.80 ± 81.30, 812.80 ± 45.22, and 956.00 ± 39.96 µS/cm, respectively. TSS were 338.20 ± 38.80, 45.00 ± 5.79, and 187.80 ± 27.58 mg/L, respectively. COD were 274.80 ± 20.46, 35.00 ± 5.52, and 139.80 ± 25.53 mg/L, respectively. BOD5 were 186.40 ± 68.68, 26.20 ± 4.82, and 81.80 ± 15.63 mg/L, respectively. Mercury values were 1.93 ± 0.38, 4.04 ± 0.38, and 14.37 ± 1.65 µg/L, respectively. Lead values were 434.70 ± 202.42, 310.50 ± 4.09, and 367.43 ± 94.01 µg/L, respectively. Cadmium values were 79.59 ± 19.48, 109.94 ± 8.43, and 80.26 ± 7.85 µg/L, respectively. Copper values were 27.66 ± 3.33, 30.84 ± 1.65, and 28.32 ± 2.36 mg/L, respectively. Iron was detected only on the STEP-KOS with an average of 71.01 ± 37.83 mg/L. Hafnium values were 50.27 ± 4.49 and 51.58 ± 4.61 mg/L for WWTS-KOS and UHC-BOG, respectively. Silver values were 34.26 ± 3.06 for WWTS-KOS. On the three sites, the differences found were significant (p < 0.05). Liquid hospital effluents from Ouagadougou discharged into nature on the whole do not compile with the Burkinabè normative values for the discharge of wastewater into the environment.

Global mercury concentrations in biota: their use as a basis for a global biomonitoring framework

An important provision of the Minamata Convention on Mercury is to monitor and evaluate the effectiveness of the adopted measures and its implementation. Here, we describe for the first time currently available biotic mercury (Hg) data on a global scale to improve the understanding of global efforts to reduce the impact of Hg pollution on people and the environment. Data from the peer-reviewed literature were compiled in the Global Biotic Mercury Synthesis (GBMS) database (>550,000 data points). These data provide a foundation for establishing a biomonitoring framework needed to track Hg concentrations in biota globally. We describe Hg exposure in the taxa identified by the Minamata Convention: fish, sea turtles, birds, and marine mammals. Based on the GBMS database, Hg concentrations are presented at relevant geographic scales for continents and oceanic basins. We identify some effective regional templates for monitoring methylmercury (MeHg) availability in the environment, but overall illustrate that there is a general lack of regional biomonitoring initiatives around the world, especially in Africa, Australia, Indo-Pacific, Middle East, and South Atlantic and Pacific Oceans. Temporal trend data for Hg in biota are generally limited. Ecologically sensitive sites (where biota have above average MeHg tissue concentrations) have been identified throughout the world. Efforts to model and quantify ecosystem sensitivity locally, regionally, and globally could help establish effective and efficient biomonitoring programs. We present a framework for a global Hg biomonitoring network that includes a three-step continental and oceanic approach to integrate existing biomonitoring efforts and prioritize filling regional data gaps linked with key Hg sources. We describe a standardized approach that builds on an evidence-based evaluation to assess the Minamata Convention's progress to reduce the impact of global Hg pollution on people and the environment.

The global challenge of reducing mercury contamination from artisanal and small-scale gold mining (ASGM): evaluating solutions using generic theories of change

Mercury contamination from artisanal and small-scale gold mining (ASGM) currently accounts for 37% of the global total, often affecting tropical regions where regulations, if they exist, are often poorly enforced. Ingestion by people and other animals damages the nervous, reproductive, and cognitive systems. Despite the efforts of many organizations and governments to curb mercury releases from ASGM, it is increasing globally. There are many possible interventions, all with significant complexity and cost. Therefore, we recommend taking an established systematic approach to articulate the current situation and construct theories of change (ToC) for different possible interventions for any government or organization trying to solve this problem. Here we present a high-level situation analysis and generic ToC to support a more coordinated approach that explicitly builds upon previous experience to identify organization- and situation-appropriate engagement on this issue. We then illustrate the use of these generic models to construct a specific ToC with a policy-focused entry point. This includes interventions through (1) engagement with the global Minamata Convention on Mercury; (2) support for existing national laws and policies connected to ASGM and mercury contamination; and (3) engagement of indigenous people and local communities with governments to meet the governments' legal obligations. By methodically articulating assumptions about interventions, connections among actions, and desired outcomes, it is possible to create a more effective approach that will encourage more coordination and cooperation among governments and other practitioners to maximize their investments and support broad environmental and socio-political outcomes necessary to address this pernicious problem.

Translational toxicology of metal(loid) species: linking their bioinorganic chemistry in the bloodstream to organ damage onset

The quantification of arsenic, mercury, cadmium and lead in the human bloodstream is routinely used today to assess exposure to these toxic metal(loid)s, but the interpretation of the obtained data in terms of their cumulative health relevance remains problematic. Seemingly unrelated to this, epidemiological studies strongly suggest that the simultaneous chronic exposure to these environmental pollutants is associated with the etiology of autism, type 2 diabetes, irritable bowel disease and other diseases. This from a public health point of view undesirable situation urgently requires research initiatives to establish functional connections between human exposure to multiple toxic metal(loid) species and adverse health effects. One way to establish causal exposure-response relationships is a molecular toxicology approach, which requires one to unravel the biomolecular mechanisms that unfold after individual toxic metal(loid)s enter the bloodstream/organ nexus as these interactions ultimately determine which metabolites impinge on target organs and thus provide mechanistic links to diseases of unknown etiology. In an attempt to underscore the importance of the toxicological chemistry of metal(loid)s in the bloodstream, this review summarizes recent progress into relevant bioinorganic processes that are implicated in the etiology of adverse organ-based health effects and possibly diseases. A better understanding of these bioinorganic processes will not only help to improve the regulatory framework to better protect humans from the adverse effects of toxic metal(loid) species, but also represents an important starting point for the development of treatments to ameliorate pollution-induced adverse health effects on human populations, including pregnant women, the fetus and children.

Mercury binding to proteins disclosed by ESI MS experiments: The case of three organomercurials

Solution interactions of three organomercury compounds, i.e., methylmercury chloride, thimerosal and phenylmercury acetate, with a group of biochemically relevant proteins, namely cytochrome c (Cyt c), ribonuclease A (RNase A), carbonic anhydrase I (hCA I), superoxide dismutase (SOD), and serum albumin (HSA), were investigated using an established ESI MS approach. Temporal analysis of sample aliquots provided insight into the binding kinetics, while comparative analysis of the obtained mass spectra disclosed adduct formation of each mercurial with the tested proteins and the relative abundance of the species. The three organomercurials bind, exclusively and tightly, to free cysteine residues as no binding was observed in the case of proteins lacking such groups. hCA I, SOD and HSA formed distinct mercury adducts, preserving the Hg bound alkyl/aryl ligands; yet, the three organomercurials displayed significant differences in reactivity in relation to their chemical structure. The investigation was then extended to analyze the reactions with the C-terminal dodecapeptide of the enzyme human thioredoxin reductase, which contains a characteristic selenol-thiol moiety: tight Hg binding was observed. Notably, this peptide was able to remove effectively and completely the alkyl/aryl ligands of the three tested organomercurials; this behavior may be relevant to the detoxification mechanism of organomercurials in mammals. Finally, a competition experiment was carried out to establish whether protein bound mercury centers may be displaced by other competing metals. Interestingly, and quite unexpectedly, we observed that a protein bound mercury fragment may be partially displaced from its coordination site in hCA I by the medicinal gold compound auranofin.

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.

Artisanal gold mining in Kakamega and Vihiga counties, Kenya: potential human exposure and health risk

Artisanal and small-scale gold mining (ASGM) represents 20% of gold supply and 90% of gold mining workforce globally, which operates in highly informal setups. Pollutants from mined ores and chemicals introduced during gold processing pose occupational and inadvertent health risks to the extent that has not been well elucidated in Africa. Trace and major elements were analysed using inductively coupled plasma mass spectrometry in soil, sediment and water samples from 19 ASGM villages in Kakamega and Vihiga counties. Associated health risks for residents and ASGM workers were assessed. This paper focuses on As, Cd, Cr, Hg, Ni and Pb for which 96% of soil samples from mining and ore processing sites had As concentrations up to 7937 times higher than the US EPA 12 mg kg-1 standard for residential soils. Soil Cr, Hg and Ni concentrations in 98%, 49% and 68% of the samples exceeded respective USEPA and CCME standards, with 1-72% bioaccessibility. Twenty-five percentage of community drinking water sources were higher than the WHO 10 µg L-1 drinking water guideline. Pollution indices indicated significant enrichment and pollution of soils, sediment and water in decreasing order of As > Cr > Hg > Ni > Pb > Cd. The study revealed increased risks of non-cancer health effects (98.6) and cancer in adults (4.93 × 10-2) and children (1.75 × 10-1). The findings will help environment managers and public health authorities better understand the potential health risks in ASGM and support evidence-based interventions in ASGM processes, industrial hygiene and formulation of public health policy to protect residents and ASGM workers' health in Kenya.

Our evolved understanding of the human health risks of mercury

Mercury (Hg) is a chemical of health concern worldwide that is now being acted upon through the Minamata Convention. Operationalizing the Convention and tracking its effectiveness requires empathy of the diversity and variation of mercury exposure and risk in populations worldwide. As part of the health plenary for the 15th International Conference on Mercury as a Global Pollutant (ICMGP), this review paper details how scientific understandings have evolved over time, from tragic poisoning events in the mid-twentieth century to important epidemiological studies in the late-twentieth century in the Seychelles and Faroe Islands, the Arctic and Amazon. Entering the twenty-first century, studies on diverse source-exposure scenarios (e.g., ASGM, amalgams, contaminated sites, cosmetics, electronic waste) from across global regions have expanded understandings and exemplified the need to consider socio-environmental variables and local contexts when conducting health studies. We conclude with perspectives on next steps for mercury health research in the post-Minamata Convention era.

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.

Adverse Health Effects and Mercury Exposure in a Colombian Artisanal and Small-Scale Gold Mining Community

The aim of this study was, first of all, to associate the mercury (Hg) concentrations and respiratory functions of the gold miners in the artisanal small-scale gold mining (ASGM) environment in San Martín de Loba, Colombia. We carried out a cross-sectional study using a survey whereby we collected basic demographic information, occupational medical history, and applied two validated questionnaires (Q16 and SF36). We measured Hg levels in all volunteers using direct thermal decomposition-atomic absorption spectrometry. Univariate and bivariate statistical analyses were carried out for all variables, performing logistic regression to assess the effect of ASGM on health outcomes. Volunteers enrolled (n = 124) were between the ages of 20 and 84 years (84% miners and 79% males). No changes were found in the systolic blood pressure, diastolic blood pressure, and heart rate from the ASGM miners, in crude and adjusted statistical analyses. ASGM miners increased 8.91 (95% confidence interval, 1.55-95.70) times the risk of having these than of having neurotoxic effects. Concentrations of total whole blood mercury (T-Hg) in all participants ranged from 0.6 to 82.5 with a median of 6.0 μg/L. Miners had higher T-Hg concentrations than non-miners (p-value = 0.011). Normal and abnormal respiratory spirometry patterns showed significant differences with the physical role and physical function of quality-of-life scales (the (p-value was 0.012 and 0.004, respectively). The spirometry test was carried out in 87 male miners, with 25% of these miners reporting abnormalities. Out of these, 73% presented a restrictive spirometry pattern, and 27%, an obstructive spirometry pattern. The ASGM population had higher Hg concentrations and worse neurotoxic symptomatology than non-miners of the same community.

Integrative Metallomics Studies of Toxic Metal(loid) Substances at the Blood Plasma–Red Blood Cell–Organ/Tumor Nexus

Globally, an estimated 9 million deaths per year are caused by human exposure to environmental pollutants, including toxic metal(loid) species. Since pollution is underestimated in calculations of the global burden of disease, the actual number of pollution-related deaths per year is likely to be substantially greater. Conversely, anticancer metallodrugs are deliberately administered to cancer patients, but their often dose-limiting severe adverse side-effects necessitate the urgent development of more effective metallodrugs that offer fewer off-target effects. What these seemingly unrelated events have in common is our limited understanding of what happens when each of these toxic metal(loid) substances enter the human bloodstream. However, the bioinorganic chemistry that unfolds at the plasma/red blood cell interface is directly implicated in mediating organ/tumor damage and, therefore, is of immediate toxicological and pharmacological relevance. This perspective will provide a brief synopsis of the bioinorganic chemistry of AsIII, Cd2+, Hg2+, CH3Hg+ and the anticancer metallodrug cisplatin in the bloodstream. Probing these processes at near-physiological conditions and integrating the results with biochemical events within organs and/or tumors has the potential to causally link chronic human exposure to toxic metal(loid) species with disease etiology and to translate more novel anticancer metal complexes to clinical studies, which will significantly improve human health in the 21st century.

Health and Safety Risk Mitigation among Artisanal and Small-Scale Gold Miners in Zimbabwe

Artisanal and small-scale gold mining (ASGM) is often associated with no or compromised attention to health and safety. Although headlines of fatal accidents in Zimbabwe characterise ASGM, little attention is paid to prevention strategies. This study, therefore, explores health and safety risk mitigation in ASGM in Zimbabwe to inform prevention strategies. A qualitative design was used with focus group discussions and in-depth interviews. Data were analysed using thematic analysis, coding, and descriptive statistics. Reported factors contributing to compromised health and safety included immediate causes, workplace factors, ASM related factors, and contextual factors, with interconnectedness between the causal factors. In addition, factors related to ASGM were significant. For risk mitigation, formalisation, organisation of risk reduction, behaviour change, and enforcement of prevention strategies is proposed. A multi-causal analysis is recommended for risk assessment and accident investigation. A multi-stakeholder approach could be considered for risk mitigation including community and public health interventions. However, risk mitigation has been characterised by gaps and weaknesses such as lacking ASM policy, lack of capital, poor enforcement, negative perceptions, and non-compliance. Therefore, we recommend addressing the threats associated with health and safety mitigation to ensure health and safety protection in ASGM.

Assessing the knowledge and practices of occupational safety and health in the artisanal and small-scale gold mining sector of Ghana: A case of obuasi

It is noted that most developing countries such as Ghana are still grappling with health and safety policies and practices as governments and corporations have made insignificant efforts. This study utilized a questionnaire since it is suitable for both illiterate and literate respondents and allows for the gathering of massive quantities of data in a short space of time. The descriptive statistics, chi-square, likelihood ratio test regression, and correlation were used to assess the occupational safety and health knowledge and practices of employees in the artisanal small-scale gold mine in Obuasi. Although majority of the respondents had less than 5 years of job experience, however about 36% and 19% of the respondents had between 4-10 years and 11-15 years of experience respectively. However, the study further observed that an increase in health and safety practices such as safety training, committee, education, facilities, etc. will increase the level of knowledge of respondents on health and safety policies. The study further revealed that the more health and safety practices, the higher the primary responsibility of site managers to ensure that workers are practicing safety. However, the general working conditions of respondents did not meet acceptable standards as revealed by the observation checklist. The study, therefore, recommends that prime Stakeholders in the ASGM need to consider investing in future research on ASGM safety issues to acquire accurate database on ASGM operations safety.

Mercury Exposure in Artisanal Mining: Assessing the Effect of Occupational Activities on Blood Mercury Levels Among Artisanal and Small-Scale Goldminers in Ghana

A cross-sectional survey of 425 male artisanal and small-scale goldminers (ASGM) was conducted to examine the relationship between the occupational activities of the miners and their blood mercury levels while controlling for relevant biosocial and socio-cultural factors. The data was subjected to descriptive and inferential statistics. Initial findings showed that 43.29% of the ASGM miners had blood mercury levels above the occupational exposure threshold. Among the occupational factors, ASGM miners who amalgamate gold, burn amalgam, and ASGM miners who smelt gold were 2.260, 1.881, and 2.094 times respectively more likely to have high blood mercury levels as compared to ASGM miners who did not carry out these activities. Also, ASGM miners who suck excess mercury with their mouth (OR = 0.197, p < 0.001) were less likely to have high blood mercury levels. For the biosocial and socio-cultural attributes, high blood mercury levels was less likely among older ASGM miners (OR = 0.507, p < 0.05). Inversely, high blood mercury levels was more likely among ASGM miners who are married (OR = 1.627, p < 0.05), ASGM miners with junior (OR = 2.240, p < 0.001) and senior (OR = 1.575, p < 0.05) high school education, and ASGM miners who have 6-10 years (OR = 3.802, p < 0.001) and above 10 years (OR = 2.591, p < 0.001) work experience. ASGM miners who amalgamate gold, burn amalgam, and smelt gold are exposed to mercury and are at risk of mercury poisoning. This could, however, be minimized with the right capturing devices and personal protective equipment. This notwithstanding, unsafe, and unsustainable occupational practices such as working in mercury contaminated water and sucking excess mercury with the mouth should be discouraged.

Reducing disease and death from Artisanal and Small-Scale Mining (ASM) - the urgent need for responsible mining in the context of growing global demand for minerals and metals for climate change mitigation

Artisanal and small-scale mining (ASM) takes place under extreme conditions with a lack of occupational health and safety. As the demand for metals is increasing due in part to their extensive use in 'green technologies' for climate change mitigation, the negative environmental and occupational consequences of mining practices are disproportionately felt in low- and middle-income countries. The Collegium Ramazzini statement on ASM presents updated information on its neglected health hazards that include multiple toxic hazards, most notably mercury, lead, cyanide, arsenic, cadmium, and cobalt, as well as physical hazards, most notably airborne dust and noise, and the high risk of infectious diseases. These hazards affect both miners and mining communities as working and living spaces are rarely separated. The impact on children and women is often severe, including hazardous exposures during the child-bearing age and pregnancies, and the risk of child labor. We suggest strategies for the mitigation of these hazards and classify those according to primordial, primary, secondary, and tertiary prevention. Further, we identify knowledge gaps and issue recommendations for international, national, and local governments, metal purchasers, and employers are given. With this statement, the Collegium Ramazzini calls for the extension of efforts to minimize all hazards that confront ASM miners and their families.

Accidents, Injuries, and Safety among Artisanal and Small-Scale Gold Miners in Zimbabwe

Artisanal and small-scale gold mining (ASGM) employs 14-19 million people globally. There is limited research on accidents, injuries, and safety in Zimbabwe's ASGM. This study investigates the prevalence of accidents and injuries, as well as the associated risks and existing safety practices. A cross-sectional survey was conducted among artisanal and small-scale gold miners. Data from 401 participants were analyzed using descriptive statistics and regression analysis. The prevalence of accidents and injuries was 35.0% and 25.7%. Accidents associated with experiencing injuries included mine collapses and underground trappings. The major injury risk factors were digging, blasting, being male, being 18-35 years old, crushing, and the underground transportation of workers and materials. Injuries were reported highest among the miners working 16 to 24 h per day. Participants had heard about personal protective equipment (PPE). There was training and routine inspections mainly on PPE use. Mine owners and supervisors were reported as responsible for OSH, which was mainly PPE use. Practices including the use of wire winch ropes and escape routes were rare. There was ignorance on underground mine shaft support. The mining regulations that had the potential to introduce comprehensive safety controls were not adaptable. We recommend applicable health and safety regulations for Zimbabwe's ASGM.

Hazards and Control Measures among Artisanal and Small-Scale Gold Miners in Zimbabwe

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Climate Change, Conflict, and Resource Extraction: Analyses of Nigerian Artisanal Mining Communities and Ominous Global Trends

Background:

The 2010 lead poisoning outbreak that claimed the lives of more than 400 children in artisanal gold mining villages in Zamfara, Nigeria is the tragic result of high gold prices, a geologic anomaly, and processing of ores in residential areas. Today, these villages face a growing crisis related to conflict and climate change. While the situation in Zamfara is unparalleled in many ways, the interactions between climate change, conflict, and mining consistently overlap a global scale. The scope of this analysis extends beyond the Nigerian crisis.

Objectives:

Understanding the complexities of challenges faced in Zamfara provides insight into how these issues impact vulnerable communities globally, and which strategies should be considered to solve this wicked problem.

Methods:

Analysis of the relationships between climate change, conflict, and mining in Zamfara and globally via literature review and examination of current events in the Sahel region.

Findings:

Supporting healthy artisanal mining communities, as was prioritized in Zamfara, must be a focus of environmental, health, and mineral management policies. This includes the consideration of multiple environmental health challenges, the protection of vulnerable groups, government-supported formalization programs, and meaningful involvement of local leadership in developing, implementing, and sustaining intervention strategies to enshrine ASM as a poverty reduction, climate change adaptation strategy.

Conclusions:

Rapidly rising metal prices and demand will continue to fuel environmental health crises associated with mining. Given Africa’s growing role in the global mineral economy and the massive number of subsistence communities who will continue to be impacted by climate change, strategies that support responsible artisanal mining are both a necessity for preventing future health crises and an opportunity for promoting regional stability and peace.

Analysis of the Mercury Distribution in Blood as a Potential Tool for Exposure Assessment - 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.

Mercury Contamination: A Growing Threat to Riverine and Urban Communities in the Brazilian Amazon

In recent decades, widespread and uncontrolled use of mercury (Hg) in artisanal small-scale gold mining has released thousands of tons of mercury-contaminated waste in the Amazon biome, endangering the largest tropical rainforest worldwide. In this study, we assessed and compared blood Hg levels in individuals living in urban and riverine areas in the lower Tapajós basin and examined the association between Hg exposure and specific biochemical parameters. In total, 462 adults from eight riverine communities and one urban area were assessed. Overall, 75.6% of the participants exhibited Hg concentrations exceeding the safe limit (10 µg/L). Hg exposure was higher in the riverine population (90%) than in urban areas (57.1%). Mean Hg levels were 21.8 ± 30.9 µg/L and 50.6 µg/L in urban and riverine residents, respectively. The mean Hg level was higher in those aged 41–60 years in both urban and riparian areas, with riparian residents exhibiting a mean double that of urban residents. The highest glucose and hepatic biomarker levels were detected in the urban area, whereas the highest levels of renal biomarker occurred in the riverine population. Our results indicate that Hg contamination remains a persistent challenge for the urban population of Santarém, a major city in the Brazilian Amazon.

Mercury Exposure and Its Health Effects in Workers in the Artisanal and Small-Scale Gold Mining (ASGM) Sector—A Systematic Review

Gold is one of the most valuable materials but is frequently extracted under circumstances that are hazardous to artisanal and small-scale gold miners’ health. A common gold extraction method uses liquid mercury, leading to a high exposure in workers. Therefore, a systematic review according to the PRISMA criteria was conducted in order to examine the health effects of occupational mercury exposure. Researching the databases PubMed^®, EMBASE^® and Web of Science^TM yielded in a total of 10,589 results, which were screened by two independent reviewers. We included 19 studies in this review. According to the quantitative assessment, occupational mercury exposure may cause a great variety of signs and symptoms, in particular in the field of neuro-psychological disorders, such as ataxia, tremor or memory problems. However, many reported symptoms were largely unspecific, such as hair loss or pain. Most of the included studies had a low methodological quality with an overall high risk of bias rating. The results demonstrate that occupational mercury exposure seriously affects miners’ health and well-being.

Environmental and health risks posed to children by artisanal gold mining: A systematic review

There are an estimated 5 million children working in artisanal and small-scale gold mines worldwide; however, the hazards are poorly characterized and often underreported. We systematically reviewed the literature on reports of hazards among children as a consequence of such activities through PubMed database using pre-defined search terms. We identified 113 articles published between 1984 and 2021 from 31 countries. Toxicological hazards were reported in 91 articles, including mercury, lead, and arsenic. Infectious hazards, noted in 18 articles, included malaria, cholera, and hepatitis. Six articles reported occupational hazards, including malnutrition, heat stroke, and reactive airway disease. Three articles reported traumatic hazards, including cave-ins, burns, animal attacks, falls, and weapon-inflected wounds. Those findings likely indicate a profound underreporting of the prevalence and consequences of such hazards among children. More work is needed both to characterize the burdens of those hazards and to address the underlying drivers of child labor in those settings.

Examining Preference Heterogeneity in Best-Worst Scaling: Case of Preferences for Job Opportunities in Artisanal Small-Scale Gold Mining (ASGM) Communities in Indonesia

This research empirically examines the preferences for job-related attributes among rural villagers living close to artisanal and small-scale gold mining (ASGM) in Indonesia. Based on hypothetical scenarios in which a private company collaborates with the local government to establish a food processing industry in these villages, a questionnaire survey designed with best-worst scaling (BWS) was administered to households to determine their preferences. Additionally, the heterogeneity among the villagers was examined by applying a latent class logit (LCL) model. The main household survey was conducted in 2019 in Bone Bolango Regency, Gorontalo Province. The estimation results revealed that villagers are separated into four classes, and each class has different and unique preferences. Creating more job opportunities for society is a highly evaluated attribute; however, the preference for skill acquisition differs among groups. The results indicate that accounting for heterogeneous preferences regarding job opportunities is helpful to delink dependency on ASGM and health hazards and improve the livelihoods of rural villagers. The study yields key information to substantially reduce environmental and health hazards in the poverty-plagued ASGM community by facilitating job opportunities in Indonesia.

Economic Impacts on Human Health Resulting from the Use of Mercury in the Illegal Gold Mining in the Brazilian Amazon: A Methodological Assessment

Artisanal small-scale gold mining (ASGM) in the Amazon results in the dumping of tons of mercury into the environment annually. Despite consensus on the impacts of mercury on human health, there are still unknowns regarding: (i) the extent to which mercury from ASGM can be dispersed in the environment until it becomes toxic to humans; and (ii) the economic value of losses caused by contamination becomes evident. The main objective of this study is to propose a methodology to evaluate the impacts of ASGM on human health in different contexts in the Brazilian Amazon. We connect several points in the literature based on hypotheses regarding mercury dispersion in water, its transformation into methylmercury, and absorption by fish and humans. This methodology can be used as a tool to estimate the extent of environmental damage caused by artisanal gold mining, the severity of damage to the health of individuals contaminated by mercury and, consequently, can contribute to the application of fines to environmental violators. The consequences of contamination are evaluated by dose-response functions relating to mercury concentrations in hair and the development of the following health outcomes: (i) mild mental retardation, (ii) acute myocardial infarction, and (iii) hypertension. From disability-adjusted life years and statistical life value, we found that the economic losses range from 100,000 to 400,000 USD per kilogram of gold extracted. A case study of the Yanomami indigenous land shows that the impacts of mercury from illegal gold mining in 2020 totaled 69 million USD, which could be used by local authorities to compensate the Yanomami people.

Registration status, mercury exposure biomarkers, and neuropsychological assessment of artisanal and small-scale gold miners (ASGM) from the Western Region of Ghana

The artisanal and small-scale gold mining (ASGM) sector is estimated to be the largest anthropogenic source of mercury pollution worldwide, and not surprisingly human exposures in this sector are amongst the highest of all population groups. While formalization of the sector has been proposed as a solution to help improve health and safety within ASGM sites, there are few empirical studies in support of this notion. The objective of this study was to assess if individuals working in ASGM sites that are registered have reduced mercury exposures and better neuropsychological scores than workers from unregistered sites. To achieve this objective, we studied biological samples (urine, hair) and survey data from a study of 404 ASGM workers (of which, 295 worked in registered ASGM sites) conducted in Tarkwa (Ghana) in 2014. Between miners working in registered and unregistered sites, there were few differences in socio-demographic characteristics. Median urinary mercury concentration (specific gravity-corrected) among those from unregistered mines was nearly 3-fold higher than those from the registered mines (18.5 versus 6.6 μg/L), and in the overall population the median concentration was 10.0 μg/L, and ranged from 0.3 to 2499 μg/L. Mercury biomarkers varied across ASGM work categories (e.g., those who burned or amalgamated had the highest) and users of personal protective equipment. Nearly 30% of the study population indicated having some challenges concerning, for example, reduced appetite, hair loss, or excess salivation. Ataxia and rigidity of gait were absent in most of the participants, and for those with slight, moderate, or marked responses, there were no differences between miners from registered and unregistered sites, across work groups, as well as in reference to mercury biomarker measures. For the pencil tapping, Frostig, matchbox, and Wechsler tests, no striking differences were found though a correlation was found between urinary mercury levels and matchbox scores among those who amalgamate and burn, and scores were similar to past studies using the same tests in ASGM sites. We believe this is the first study to compare mercury exposures and neuropsychological test results between miners from registered and unregistered ASGM sites. In doing so, the research findings provide the necessary evidence for stakeholders and parties of the Minamata Convention considering various response options to help fulfill their obligations.

Sex-specific neurotoxic effects of heavy metal pollutants: Epidemiological, experimental evidence and candidate mechanisms

The heavy metals lead (Pb), mercury (Hg), and cadmium (Cd) are ubiquitous environmental pollutants and are known to exert severe adverse impacts on the nervous system even at low concentrations. In contrast, the heavy metal manganese (Mn) is first and foremost an essential nutrient, but it becomes neurotoxic at high levels. Neurotoxic metals also include the less prevalent metalloid arsenic (As) which is found in excessive concentrations in drinking water and food sources in many regions of the world. Males and females often differ in how they respond to environmental exposures and adverse effects on their nervous systems are no exception. Here, we review the different types of sex-specific neurotoxic effects, such as cognitive and motor impairments, that have been attributed to Pb, Hg, Mn, Cd, and As exposure throughout the life course in epidemiological as well as in experimental toxicological studies. We also discuss differential vulnerability to these metals such as distinctions in behaviors and occupations across the sexes. Finally, we explore the different mechanisms hypothesized to account for sex-based differential susceptibility including hormonal, genetic, metabolic, anatomical, neurochemical, and epigenetic perturbations. An understanding of the sex-specific effects of environmental heavy metal neurotoxicity can aid in the development of more efficient systematic approaches in risk assessment and better exposure mitigation strategies with regard to sex-linked susceptibilities and vulnerabilities.

Mercury Exposure among E-Waste Recycling Workers in Colombia: Perceptions of Safety, Risk, and Access to Health Information

Exposures to the toxic element mercury (Hg) are exceptionally high among recycling workers globally. Recycling is a growing sector in Colombia, yet workers who directly handle e-waste are often unaware of the risks of exposure to mercury from post-consumer lighting products (e.g., fluorescent lamps). This qualitative study aimed to understand how recycling workers perceive their own risks from mercury exposure and how they find information about these risks, through interviews (n = 35) at the three largest formal recycling facilities in Colombia. Workers' risk perception was generally disconnected from their likely actual exposure to mercury, instead often seen juxtaposed to co-workers who worked more directly with hazardous waste. Recycling workers, who were predominantly men from lower-income socioeconomic backgrounds, had limited knowledge of health risks due to mercury exposure and were more likely to receive health-related information from informal sources. Over a third of interviewees had searched online for information about occupational health risks of mercury, but these searches were perceived as unsatisfactory due to information being difficult to find, not available in Spanish, or related to mercury exposure via seafood or mining rather than recycling. Workers expressed (over)confidence in personal protective equipment and concern about frequent employee turnover. This study points to weaknesses in environmental health literacy and public health communication around toxic exposures to mercury in the workplace. Stronger regulation and enforcement are needed to prevent toxic exposures and promote worker health equity.

Urgent Need for a Comprehensive Public Health Response to Artisanal Small-Scale Mining

Informal sector mining is a growing enterprise in countries around the world providing livelihood to >40 million self-employed miners. The use of mercury in gold processing has been the sole focus of most research and public health interventions in artisanal mining. Few programs work to improve health among communities mining other commodities including sand, aggregates, quartz, lead, gemstones, coal and other materials. Although mercury is a major environmental challenge in countries with extensive gold mining, artisanal miners are also exposed to silica dust, metals and other safety hazards. The available evidence regarding hazardous exposures among self-employed miners suggests that the public health implications are much broader. There is a growing body of evidence linking exposures to silica dust to tuberculosis and other lung diseases among artisanal miners. Studies have also documented exposures to lead and other metals including arsenic, cadmium, cobalt and chromium in informal mining communities. Silica-dust exposures are higher in artisanal mining than levels reported in large industrial mining. There is ample evidence that artisanal miners are experiencing health impacts not just from mercury but also from exposures to noise, silica dust and metals. Practical, low-cost solutions have been pilot tested and shown to reduce respirable silica dust and metal exposures among miners and ore processors. Governments, development agencies and global health funders should invest in comprehensive public health programs to respond to these needs.

Determinants of health and health needs assessment of artisanal and small-scale gold miners in Kadoma, Zimbabwe: A mixed method approach

BACKGROUND

The role of artisanal and small-scale gold mining (ASGM) as a source of income is rapidly gaining importance in the economically difficult times in Zimbabwe. Small-scale miners are now responsible for over 50% of the Zimbabwean gold production. However, the sector is still characterised by high labour-intensity, low productivity and capital, limited mechanisation and outdated technologies. Since increasing efforts in recent years to improve miners' health while reducing the exposure to mercury have not been effective, a more sustainable approach is needed to identify interventions targeting the health of artisanal and small-scale miners and the mining communities.

OBJECTIVE

The main objective of this study was the accurate and extensive empirical identification of the determinants of health in ASGM and of the miners' health needs. In tandem with these needs, topics which generate more effective, sustainable, and feasible future health interventions targeting occupational health should be identified.

METHODS

Based on the identification of determinants of health, a health needs assessment (HNA) was used to conduct miners' needs by applying a mixed methods approach and triangulation. This included qualitative and quantitative interviews with individuals, group interviews, focus group discussions, observations and informal conversations.

RESULTS

There were 85 structured and 84 semi-structured interviews, a focus group discussion, and observations conducted. Six main themes were identified around which miners' health needs can be aggregated as follows: living conditions, nutrition and hygiene; safe work environment and mining processes; financial support; health care services; formalisation and education.

DISCUSSION

The following aspects were considered most important for sustainable interventions: possible health impacts, feasibility, value for miners and their willingness to adapt. Accordingly, interventions aiming at increasing education, knowledge and awareness of miners were identified as most promising in improving occupational health.

Total blood mercury and its determinants in New Zealand children and adults

BACKGROUND

Mercury is a widespread persistent environmental pollutant associated with adverse health effects.

OBJECTIVE

This first national biomonitoring survey of blood total mercury (tHg) conducted in New Zealand aimed to provide baseline data and identify exposure determinants.

METHODS

Blood was collected from 191 children (age 5-18 years) and 304 adults (20-65) in 2014-2016 and analysed for tHg using inductively coupled plasma mass spectrometry. Linear regression was used to assess associations with demographic and lifestyle factors.

RESULTS

Blood mercury was detected in 93% of children and 99% of adults, with geometric means (GMs) of 0.86 and 1.65 µg/L, respectively. The 60-65-year olds had the highest GM (2.34 µg/L). Regression indicated that tHg was 40% higher in boys compared to girls. Eating fish ≥ 3 times/week (compared to ≤once/week) was associated with 2.7 and 1.7 times higher tHg in children and adults, respectively. Shellfish consumption was also associated with higher tHg. High daily tap water consumption (≥2 L for children, ≥3 L for adults) was associated with lower tHg. In adults, smoking and milk consumption were associated with higher tHg.

SIGNIFICANCE

Fish and shellfish consumption is a strong determinant of New Zealanders blood tHg levels, with water and milk consumption possibly acting as modulating factors.

Health Studies in the Context of Artisanal and Small-Scale Mining: A Scoping Review

Artisanal and small-scale mining (ASM) is an important livelihood activity in many low- and middle-income countries. It is widely acknowledged that there are a myriad of health risk and opportunities associated with ASM. However, little is known with regard to which aspects of health have been studied in ASM settings. We conducted a scoping review of peer-reviewed publications, using readily available electronic databases (i.e., PubMed, Scopus, and Web of Science) from inception to 14 July 2020. Relevant information was synthesized with an emphasis on human and environmental exposures and health effects in a context of ASM. Our search yielded 2764 records. After systematic screening, 176 health studies from 38 countries were retained for final analysis. Most of the studies (n = 155) focused on health in ASM extracting gold. While many of the studies included the collection of environmental and human samples (n = 154), only few (n = 30) investigated infectious diseases. Little attention was given to vulnerable groups, such as women of reproductive age and children. Our scoping review provides a detailed characterisation of health studies in ASM contexts. Future research in ASM settings should address health more comprehensively, including the potential spread of infectious diseases, and effects on mental health and well-being.

Exposure to total and methylmercury among pregnant women in Suriname: sources and public health implications

Previous research has found that women and children living in rural, interior communities in Suriname have high concentrations of mercury in hair. Freshwater fish from these areas also have high concentrations of mercury. Artisanal and small-scale gold mining operations in parts of the country use elemental mercury to extract gold from soils and sediments. Total mercury and methylmercury concentrations have been determined in hair and blood from pregnant women across the country. Pregnant women from interior communities have significantly higher concentrations of both total and methylmercury in hair (median total mercury in hair 3.64 µg/g) compared with pregnant women from two urban coastal cities, Paramaribo (0.63 µg/g) and Nickerie (0.74 µg/g). Total and methylmercury concentrations in blood and hair are highly correlated (r = 0.986, r = 0.974) with methylmercury making up 86% of the total in blood and 97% of the total in hair. Most women in the interior regions rely heavily on local fish as part of their regular diet, and many live outsides of areas with active ASGM operations. This study demonstrates that diet and fish consumption largely govern mercury exposures in pregnant women in Suriname.

A population-based mercury exposure assessment near an artisanal and small-scale gold mining site in the Peruvian Amazon

Human exposure to mercury is a leading public health problem. Artisanal and small-scale gold mining (ASGM) is a major source of global mercury emissions. Although occupational mercury exposure to miners (via mercury vapor inhalation) is known, chronic mercury exposure to nearby residents that are not miners (via mercury-contaminated fish consumption) is poorly characterized. We conducted a population-based mercury exposure assessment in 23 communities (19 rural, 4 urban) around the Amarakaeri Communal Reserve, which is bordered on the east by heavy ASGM activity. We measured total mercury in hair (N = 2083) and blood (N = 476) from March-June 2015 and performed follow-up measurements (N = 723 hair and N = 290 blood) from February-April 2016. Mercury exposure risk was highest in communities classified as indigenous, or native, regardless of proximity to mining activity. Residence in a native community (vs. non-native) was associated with mercury levels 1.9 times higher in hair (median native 3.5 ppm vs. median non-native 1.4 ppm total mercury) and 1.6 times higher in blood (median native 7.4 ng/mL vs median non-native 3.2 ng/mL total mercury). Unexpectedly, proximity to mining was not associated with exposure risk. These findings challenge common assumptions about mercury exposure patterns and emphasize the importance of population-representative studies to identify high risk sub-populations.

Occupational human exposure to mercury in artisanal small-scale gold mining communities of Colombia

With the aim of protecting human life and the environment, the Minamata Convention seeks to reduce and monitor mercury (Hg) concentrations in the environment. Artisanal and Small-scale Gold Mining (ASGM) has been identified as the most important anthropogenic source of Hg at a global scale and an important route of human exposure to Hg. In this context, this study assessed total Hg (THg) in blood, urine and hair, and methylmercury (MeHg) in human hair samples from 238 participants with occupational exposure to Hg in the most relevant ASGM communities of Colombia. Mercury concentrations in different biological matrices were related to several variables of interest such as age, gender, body mass index, fish consumption, exposure time, and specific occupational activities, such as amalgamation and amalgam burning. The median values of THg in blood (3.70 µg/L), urine (4.00 µg/L) and hair (1.37 mg/kg), and hair MeHg (1.47 mg/kg) for all participants were below permissible concentrations set by WHO. However, about 40% of the miners showed Hg concentrations in blood, urine and/or hair above the WHO thresholds. In all the biological matrices studied, miners burning amalgams showed significantly higher concentrations than miners who did not burn amalgams, with values 7-, 7-, and 8-fold higher in blood, urine and hair, respectively. A multiple linear regression model revealed that burning amalgam and fish consumption were significant predictors of Hg exposure in miners. Miners from Guainía had the highest concentrations in urine and hair, most likely due to the high manipulation and burning of amalgam, and a high fish consumption. In contrast, miners from Caldas showed the lowest Hg concentrations in all the biomarkers because they do not manipulate or burn amalgam, as well as reporting the lowest fish consumption. Our study also highlighted that gold miners exposure to Hg depends on their work practices. Therefore, the implementation of a health education programme on gold mining strategies is required, especially in Guaina, Vaupés, Córdoba, and Antioquia departments.

How Occupational Mercury Neurotoxicity Is Affected by Genetic Factors. A Systematic Review

Occupational exposure to elemental mercury still represents a significant risk in the workplace. The sensitivity of the exposed subjects varies considerably. This study aims to summarize the literature on the role of genetic factors in occupationally exposed cohorts. A systematic search of the literature was carried out on PubMed Central (PMC), MEDLINE, and Google Scholar databases in accordance with the “Preferred Reporting Items for Systematic reviews and Meta-Analyses” (PRISMA) guidelines, from 1946 to July 2020. Ten cross-sectional studies were included in the review. All studies referred to the polymorphisms that can favour some neurotoxic effects of the metal in occupational cohorts. Some genetic variants may be associated with an increase in the occupational effects of mercury. Given the limited evidence, genetic screening of all mercury-exposed workers is not recommended. However, a personalized search for polymorphisms could be taken into consideration if exposed workers report early neurotoxic symptoms.

Colorimetric detection of Hg2+ with an azulene-containing chemodosimeter via dithioacetal hydrolysis

Azulene is a bicyclic aromatic chromophore that absorbs in the visible region. Its absorption maximum undergoes a hypsochromic shift if a conjugated electron-withdrawing group is introduced at the C1 position. This fact can be exploited in the design of a colorimetric chemodosimeter that functions by the transformation of a dithioacetal to the corresponding aldehyde upon exposure to Hg2+ ions. This chemodosimeter exhibits good chemoselectivity over other metal cations, and responds with an unambiguous colour change clearly visible to the naked eye. Its synthesis is concise and its ease of use makes it appropriate in resource-constrained environments, for example in determing mercury content of drinking water sources in the developing world.

Health-related quality of life (EQ-5D + C) among people living in artisanal and small-scale gold mining areas in Zimbabwe: a cross-sectional study

Background

In Zimbabwe, an estimated 500,000 people work in the sector of artisanal and small-scale gold mining (ASGM). Two million Zimbabweans are dependent on this sector. Using mercury is common to extract gold from ore. Long term exposure to mercury can cause various adverse health conditions including chronic mercury intoxication. The influence of these adverse health effects on the health-related quality of life (HRQoL) is still unknown. The aim of this study is to assess the HRQoL of people who identify themselves as miners, and to analyze potential influencing factors, such as age, years of working with mercury and health conditions caused by mercury exposure.

Methods

This cross-sectional study assessed the HRQoL using the standardized EQ-5D + C (3 L) questionnaire and collected human specimens (blood, urine) of people living and possibly working in ASGM areas in Zimbabwe. Factors such as age, years of working with mercury and adverse health conditions possibly caused by mercury exposure were analyzed with regards to their influence on the HRQoL.

Results

The 207 participants (82% male, mean age 38 years) reported 40 different health states. Of the study participants 42.5% reported to be in complete good health while 57.5% reported being unwell in different ways. Nine participants (4.3%) were identified with chronic mercury intoxication, whereas 92 participants (33.3%) had mercury levels above the “Alert” threshold in at least one specimen. Having chronic mercury intoxication has a significant negative influence on the HRQoL, when taking into account age, gender and years of working with mercury. Cognitive problems were the most reported in the questionnaire, however, the association between this domain separately and the HRQoL was not verified.

Conclusion

This study shows that adverse health effects caused by chronic exposure to mercury, have a negative influence on the HRQoL among people living in ASGM areas.

Comparing the self-reported health-related quality of life (HRQoL) of artisanal and small-scale gold miners and the urban population in Zimbabwe using the EuroQol (EQ-5D-3L+C) questionnaire: a cross-sectional study

Background

The role of artisanal and small-scale gold mining (ASGM) as a source of income is rapidly gaining importance in the economically difficult times in Zimbabwe. Besides limited epidemiological data, no data about the self-reported health-related quality of life (HRQoL) of artisanal and small-scale gold miners exist. The aim of the project was to access HRQoL of ASGM workers to improve the data base and compare the data to the urban Zimbabwean population.

Methods

Data from 83 artisanal and small-scale gold miners in Kadoma, Zimbabwe was analysed. The HRQoL was assessed using the EuroQol dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) accompanied by the cognition add-on questionnaire (EQ-5D-3L+C) and associated visual analogue scale (VAS). We described the EQ-5D dimensions and VAS values and computed health utility (HU) values using the Zimbabwean tariff. The proportions of miners reporting no problem in each EQ-5D dimension were compared with corresponding proportions reporting any problem (moderate or severe), and mean HU and VAS values were analysed across subgroups of the sample. To test differences between subgroups, Fisher’s exact test was used and between urban and mining population, Student’s t-test was used.

Results

The reported health states of miners were homogenous, with a large amount (42%) reporting ‘full health’. Mean (SD) VAS and HU values were 81.0 (17.5) and 0.896 (0.13), respectively. Subgroup analysis showed that miners with a lower education reported significantly more problems in the dimension of daily activities and miners with mercury contact had more problems in the dimensions of pain/discomfort and cognition. Comparison between mining and urban population showed that in the oldest age group, self-rated VAS values of miners were significantly higher than of their urban counterparts.

Conclusions

There were no significant differences in the HRQoL of mining and urban populations. However, the reason might be adverse health effects faced by the urban population that do not apply to rural mining areas. A higher education level of miners can improve the HRQoL, which is especially impaired by problems in the cognition dimension.

Localization of mercury and gold in cassava (Manihot esculenta Crantz)

The potential of cassava (Manihot esculenta Crantz.) for simultaneous Hg and Au phytoextraction was explored by investigating Hg and Au localization in cassava roots through Micro-Proton Induced X-Ray Emission, High-Resolution Transmission Electron Microscopy (HR-TEM) and X-Ray Diffractometry (XRD). The effect of Hg and Au in the cyanogenic glucoside linamarin distribution was also investigated using Matrix Assisted Laser Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (MALDI-FT-ICR-MS) imaging. Hg was located mainly in the root vascular bundle of plants grown in 50 or 100 μmol L^-1 Hg solutions. Au was localized in the epidermis and cortex or in the epidermis and endodermis for 50 and 100 μmol L^-1 Au solutions, respectively. For 50 μmol L^-1 solutions of both Hg and Au, the two metals were co-localized in the epidermis. When the Hg concentrations were increased to 100 μmol L^-1, Au was still localized to a considerable extent in the epidermis while Hg was located in all root parts. HR-TEM and XRD revealed that Au nanoparticles were formed in cassava roots. MALDI-FT-ICR-MS imaging showed linamarin distribution in the roots of control and plants and metal-exposed plants thus suggesting that linamarin might be involved in Hg and Au uptake and distribution.

Artisanal and small-scale gold mining: A cross-sectional assessment of occupational mercury exposure and exposure risk factors in Kadoma and Shurugwi, Zimbabwe

In artisanal and small-scale gold mining (ASGM) the toxic metal mercury is used for gold extraction. The objective of this cross-sectional study was to assess mercury concentrations in urine and blood and mercury-related symptoms of participants identifying themselves as miners from Kadoma and Shurugwi, Zimbabwe. Moreover, we aimed to explore possible risk factors influencing mercury body burden. In 2019, urine and blood samples of 207 participants were collected and analyzed for mercury using atomic absorption spectroscopy. All participants answered questions regarding their exposure risks. The median urine mercury value was 4.75 μg/L with a maximum of 612 μg/L. Median mercury concentration in creatinine corrected urine values was 3.98 μg/g with a maximum value of 478 μg/g. The median blood mercury value was 2.70 μg/L with a maximum of 167 μg/L. Correlations between exposure risks factors such as the lack of retort use and elevated mercury values were demonstrated. ASGM is very common in Zimbabwe. Thus, mercury exposure is a major occupational health risk for miners. Moreover, this study emphasizes the impact of exposure risk factors on the mercury body burden.

Lead and Mercury Exposure and Related Health Problems in Metal Artisan Workplaces and High-Risk Household Contacts in Thimphu, Bhutan

Background

Metal artisans have been using lead and mercury in their settings for centuries. Exposure to these toxic heavy metals causes adverse health effects. We assessed the occupational exposure of metal artisans and their high-risk household contacts at Thimphu, Bhutan.

Methods

A cross-sectional study in which 134 metal artisan center employees and 48 high-risk household contacts were tested for blood lead and mercury levels. Sociodemographic data, occupational exposure risk factors, and clinical syndrome related to lead and mercury exposure were further obtained and analyzed using EpiInfo 7.0.

Results

The mean age of the metal artisan center employees was 36.02 ± 10.3. The prevalence of elevated blood lead and mercury level was 38.4% and 51.9%, respectively. Significantly higher prevalence of mercury level was observed among the artisans compared to nonartisans (66.97 vs, 16.0). Among three centers, the goldsmith section of the Department of National Properties had the highest (94.1%). Profession as an artisan, mold designing, performing gold amalgamation, working for >8 hours a day, working for >5 years, and working at home were significant risk factors associated with elevated blood mercury level. Significant association was observed between elevated mercury level and complaints of burning or watery eyes (p=0.001), anxiety, nervousness, irritability, severe shyness (p=0.001), anxiety, nervousness, irritability, severe shyness (p=0.001), anxiety, nervousness, irritability, severe shyness (p=0.001), anxiety, nervousness, irritability, severe shyness (p=0.029), muscle aches (p=0.019), and stomach cramps or pain (p=0.009).

Conclusion

The prevalence of elevated blood mercury level is concerning among the artisans. Advocacy, proper usage of personal protective equipment, awareness on chemical safety, and hazard associated with lead and mercury usage are needed to minimize the exposure.

Maternal exposure to arsenic and mercury and associated risk of adverse birth outcomes in small-scale gold mining communities in Northern Tanzania

BACKGROUND

Exposure to arsenic and mercury in artisanal and small-scale gold mining (ASGM) communities is an issue that predominantly affects low and middle-income countries. Large epidemiology studies in these communities are rare, and the impact of such exposures on reproductive outcomes are not well understood.

OBJECTIVE

To examine associations between prenatal maternal arsenic and mercury exposure and birth outcomes in both ASGM and non-ASGM communities in Northern Tanzania.

METHODS

This longitudinal prospective study included 961 women (ASGM = 788, non-ASGM = 173) of the original cohort of 1056 who were followed until a pregnancy outcome was registered. Maternal spot urine samples and dried blood spots were used to measure total arsenic (T-As) and total mercury (T-Hg) in the second trimester of pregnancy. Data on adverse birth outcomes were collected in 5 categories: spontaneous abortion, stillbirth, preterm birth, low birth weight, and visible congenital anomalies. Mann-Whitney U-tests were used to test for differences between median T-As and T-Hg by area of residence. Logistic regression models were used to estimate the odds of stillbirth and visible congenital anomalies given maternal T-As and T-Hg levels. Modified Poisson regressions were used to estimate relative risk ratios between maternal T-As and T-Hg levels and composite adverse birth outcome, spontaneous abortion, low birth weight, and preterm birth.

RESULTS

Statistically significant differences were found in median T-As (9.6 vs. 6.3 µg/L, Mann-Whitney U-tests, Z = -3.50, p < 0.001) and median T-Hg blood concentrations (1.2 vs. 0.70 µg/L, Z = -9.88, p-value < 0.001) between women living in ASGM and non-ASGM areas respectively. In ASGM areas, the adjusted relative risk (aRR) of a composite adverse birth outcome increased with increasing T-As (aRR 1.23, 95%CI: 1.14-1.33, p < 0.0001) and T-Hg (aRR 1.17, 95%CI: 1.1-1.25, p < 0.0001) exposure. Spontaneous abortion (aRR 1.53, 95%CI: 1.28-1.83), stillbirth (adjusted odds ratio (aOR) 1.97, 95%CI: 1.45-2.66) and preterm birth (1.17, 95%CI: 1.01-1.36) were significantly associated with elevated T-As, whereas elevated T-Hg was significantly associated with stillbirth (aOR 2.49, 95%CI: 1.88-3.29) and visible congenital anomalies (aOR 2.24, 95%CI: 1.3-3.87).

CONCLUSION

Over half (54.7%) of women in ASGM areas of Northern Tanzania had adverse birth outcomes and the risk of adverse birth outcomes was significantly associated with increased prenatal exposure to arsenic and mercury.

Reducing Lead and Silica Dust Exposures in Small-Scale Mining in Northern Nigeria

Purpose

An ongoing health crisis across a large area of Northern Nigeria has resulted in hundreds of deaths and thousands of cases of lead poisoning from artisanal small-scale gold mining. Occupational Knowledge International (OK International) and Doctors Without Borders/Médecins Sans Frontières (MSF) have formed a partnership to conduct a pilot project to introduce safer mining practices in selected communities. The primary objective was to reduce lead exposures among artisanal small-scale miners and minimize take home exposures by reducing dust contamination on clothing and body surfaces.

Methods

Personal air samples were collected from miners and ore processors before and after the introduction of wet spray misting in mine processing activities to crush and grind gold ore. We measured reductions in total airborne lead and respirable silica dust levels. A total of 44 air samples were collected for airborne lead using NIOSH method 7082 and 29 air samples for respirable silica dust with NIOSH method 7500.

Results

Low-cost interventions to convert dry ore processing to wet methods with spray misting were effective at reducing arithmetic mean airborne lead levels by 95%. Mean airborne respirable silica (quartz) was reduced by 80% following the introduction of wet spray misting. Differences in geometric means between wet and dry ore processing methods were statistically significant for both airborne lead and respirable silica.

Conclusions

This pilot project has been successful in working cooperatively with miners to provide them with the necessary information and tools to reduce exposures in mining and processing, and minimize off-site contamination. As silica dust is a significant risk factor for silicosis and tuberculosis (TB), this intervention could provide public health benefits to small-scale mining communities even in areas without significant lead concentrations in the ore. Significant reductions in respirable silica and lead exposures are feasible in low-resource, small-scale mining communities.

Chemical analysis of Hg0-containing Hindu religious objects

Parad items used in Hindu practices and Ayurvedic medicines contain elemental mercury (Hg⁰) and have traditionally been used in prayer and to treat a variety of diseases including diabetes, heart conditions, and sexual dysfunction. These items are often referred to as amalgams of silver, and take the form of shivlings, statues of gods, necklaces, and other jewelry. Fourteen parad items were purchased from online vendors in India and the United States and analyzed. All items produced copious amounts of Hg⁰ vapor, with Hg⁰ concentrations exceeding 1,000,000 ng/m³ as measured using a Mercury Instruments Mercury Tracker 3000 IP atomic absorption spectrometer. Measured concentrations were highly variable, so a simple qualitative experiment employing a UV-C light source and a thin-layer chromatography plate impregnated with a fluorescent dye that glows green when irradiated at 254 nm allowed for the indirect visualization of the Hg⁰ being evolved. In addition, all items were screened using a hand-held X-ray fluorescence analyzer to estimate the concentration of Hg, Sn, Pb, As, and Cd on the surface of the item. Select samples were then digested in aqua regia and analyzed for Hg content using a direct mercury analyzer. All samples were found to exceed 20% by mass Hg. The digestates were analyzed using inductively-coupled plasma–optical emission spectrometry and were determined to be between 10–55% by mass Pb and contain up to 0.3% by mass As. While Article 4 of the Minamata Convention on Mercury specifically requires parties to stop importing, exporting, and manufacturing Hg-added products, products used in traditional and religious practices are excluded.

Rethinking Aid Allocation: Analysis of Official Development Spending on Modern Pollution Reduction

Background

Modern pollution - pollution attributable to industrialization and urbanization - is responsible for nearly 6 million deaths per year, more than all the deaths from HIV, malaria, and tuberculosis combined; yet it receives comparatively little attention in the international development agenda [1].

Objective/Methods

This study attempts to highlight the funding disparity between select key threats to global health by quantifying the levels of international official development aid (ODA) allocated to reducing pollution's negative impact on human health using a new metric - dollars spent per death caused by health threat.

Findings

Using only reported ODA spending for 2016, we calculate an average investment of $14/death for modern pollution, compared with $1,250/death for malaria, $190/death for tuberculosis, and $165/death for HIV/AIDS.

Conclusions

Although there are substantive limitations to this analysis, results are sufficient to galvanize action to better monitor and track investments in modern pollution reduction. Donor countries have failed to respond to this urgent public health crisis. Given the severity of its public health burden, there is a critical need for funding to be allocated specifically to pollution reduction.

Occupational Health Programs for Artisanal and Small-Scale Gold Mining: A Systematic Review for the WHO Global Plan of Action for Workers' Health

Background:

Workers in the informal economy often incur exposure to well-documented occupational health hazards. Insufficient attention has been afforded to rigorously evaluating intervention programs to reduce the risks, especially in artisanal and small-scale gold mining (ASGM).

Objectives:

This systematic review, conducted as part of the World Health Organization’s Global Plan of Action for Workers’ Health, sought to assess the state of knowledge on occupational health programs and interventions for the informal artisanal and small-scale gold mining (ASGM) sector, an occupation which directly employs at least 50 million people.

Methods:

We used a comprehensive search strategy for four well-known databases relevant to health outcomes: PubMed, Engineering Village, OVID Medline, and Web of Science, and employed the PRISMA framework for our analysis.

Findings:

Ten studies met the inclusion criteria of a primary study focused on assessing the impact of interventions addressing occupational health concerns in ASGM. There were no studies evaluating or even identifying comprehensive occupational health and safety programs for this sector although target interventions addressing specific hazards exist. Major areas of intervention—education and introduction of mercury-reducing/eliminating technology were identified, and the challenges and limitations of each intervention taken into assessment. Even for these, however, there was a lack of standardization for measuring outcome or impact let alone long-term health outcomes for miners and mining communities.

Conclusion:

There is an urgent need for research on comprehensive occupational health programs addressing the array of hazards faced by artisanal and small-scale miners.