Mercury Reduction in Munhena, Mozambique: Homemade Solutions and the Social Context for Change

A Bibliometric Analysis of the Scientific Research on Artisanal and Small-Scale Mining

Mineral resource exploitation is one of the activities that contribute to economic growth and the development of society. Artisanal and small-scale mining (ASM) is one of these activities. Unfortunately, there is no clear consensus to define ASM. However, its importance is relevant in that it represents, in some cases, the only employment alternative for millions of people, although it also significantly impacts the environment. This work aims to investigate the scientific information related to ASM through a bibliometric analysis and, in addition, to define the new lines that are tending to this field. The study comprises three phases of work: (i) data collection, (ii) data processing and software selection, and (iii) data interpretation. The results reflect that the study on ASM developed intensively from 2010 to the present. In general terms, the research addressed focuses on four interrelated lines: (i) social conditioning factors of ASM, (ii) environmental impacts generated by ASM, (iii) mercury contamination and its implication on health and the environment, and (iv) ASM as a livelihood. The work also defines that geotourism in artisanal mining areas is a significant trend of the last decade, explicitly focusing on the conservation and use of the geological and mining heritage and, in addition, the promotion of sustainable development of ASM.

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.

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.

A systematic review on the management and treatment of mercury in artisanal gold mining

Artisanal gold mining (AGM) continues to be a pervasive global health issue. While there are various problems associated with AGM, mercury exposure is the primary hazard contributing to adverse health effects in exposed human populations. Over the last several decades, many interventions have been developed and implemented to curb mercury emissions and releases, notwithstanding a comprehensive review of context specific effectiveness. A systematic review was conducted in order to specifically assess the impact of current mercury interventions within the AGM sector worldwide. To aid in this review, a resource pool of information on AGM and mercury, treatment and management of emissions and releases, and interventions was assembled through a search conducted via multiple search engines. This search determined that there have been many strategies used to reduce or eliminate mercury, through interventions or programs focusing on education, processing centers, or mercury alternative techniques. Education has focused on environment or health awareness or more specifically on cleaner or alternative techniques. Processing centers offered artisanal miners rudimentary equipment for grinding and amalgamation that extract less than 30% of the gold as an exchange for their tailings. Some techniques reduced mercury releases including retorts, mill leaching, vat-leaching, and others replaced mercury from the process such as magnets, direct smelting, sluices, and borax. There are both positive and negative outcomes associated with every intervention. Novel and comprehensive strategies-including mercury removal technology, miner education on mercury hazards, economic gains, and policy-are needed to address mercury public health issues associated with AGM.

The Mercury Problem in Artisanal and Small-Scale Gold Mining

Mercury-dependent artisanal and small-scale gold mining (ASGM) is the largest source of mercury pollution on Earth. In this practice, elemental mercury is used to extract gold from ore as an amalgam. The amalgam is typically isolated by hand and then heated-often with a torch or over a stove-to distill the mercury and isolate the gold. Mercury release from tailings and vaporized mercury exceed 1000 tonnes each year from ASGM. The health effects on the miners are dire, with inhaled mercury leading to neurological damage and other health issues. The communities near these mines are also affected due to mercury contamination of water and soil and subsequent accumulation in food staples, such as fish-a major source of dietary protein in many ASGM regions. The risks to children are also substantial, with mercury emissions from ASGM resulting in both physical and mental disabilities and compromised development. Between 10 and 19 million people use mercury to mine for gold in more than 70 countries, making mercury pollution from ASGM a global issue. With the Minamata Convention on Mercury entering force this year, there is political motivation to help overcome the problem of mercury in ASGM. In this effort, chemists can play a central role. Here, the problem of mercury in ASGM is reviewed with a discussion on how the chemistry community can contribute solutions. Introducing portable and low-cost mercury sensors, inexpensive and scalable remediation technologies, novel methods to prevent mercury uptake in fish and food crops, and efficient and easy-to-use mercury-free mining techniques are all ways in which the chemistry community can help. To meet these challenges, it is critical that new technologies or techniques are low-cost and adaptable to the remote and under-resourced areas in which ASGM is most common. The problem of mercury pollution in ASGM is inherently a chemistry problem. We therefore encourage the chemistry community to consider and address this issue that affects the health of millions of people.

Limitations in small artisanal gold mining addressed by educational components paired with alternative mining methods

Current solutions continue to be inadequate in addressing the longstanding, worldwide problem of mercury emissions from small artisanal gold mining. Mercury, an inexpensive and easily accessible heavy metal, is used in the process of extracting gold from ore. Mercury emissions disperse, affecting human populations by causing adverse health effects and environmental and social ramifications. Many developing nations have sizable gold ore deposits, making small artisanal gold mining a major source of employment in the world. Poverty drives vulnerable, rural populations into gold mining because of social and economic instabilities. Educational programs responding to this environmental hazard have been implemented in the past, but have had low positive results due to lack of governmental support and little economic incentive. Educational and enforced intervention programs must be developed in conjunction with governmental agencies in order to successfully eliminate this ongoing problem. Industry leaders offered hopeful suggestions, but revealed limitations when trying to develop encompassing solutions to halt mercury emissions. This research highlights potential options that have been attempted in the past and suggests alternative solutions to improve upon these methods. Some methods include buyer impact recognition, risk assessment proposals exposing a cost-benefit analysis and toxicokinetic modeling, public health awareness campaigns, and the education of miners, healthcare workers, and locals within hazardous areas of mercury exposure. These methods, paired with the implementation of alternative mining techniques, propose a substantial reduction of mercury emissions.

Mercury exposure, serum antinuclear/antinucleolar antibodies, and serum cytokine levels in mining populations in Amazonian Brazil: a cross-sectional study

Mercury is an immunotoxic substance that has been shown to induce autoimmune disease in rodent models, characterized by lymphoproliferation, overproduction of immunoglobulin (IgG and IgE), and high circulating levels of auto-antibodies directed at antigens located in the nucleus (antinuclear auto-antibodies, or ANA) or the nucleolus (antinucleolar auto-antibodies, or ANoA). We have reported elevated levels of ANA and ANoA in human populations exposed to mercury in artisanal gold mining, though other confounding variables that may also modulate ANA/ANoA levels were not well controlled. The goal of this study is to specifically test whether occupational and environmental conditions (other than mercury exposure) that are associated with artisanal gold mining affect the prevalence of markers of autoimmune dysfunction. We measured ANA, ANoA, and cytokine concentrations in serum and compared results from mercury-exposed artisanal gold miners to those from diamond and emerald miners working under similar conditions and with similar socio-economic status and risks of infectious disease. Mercury-exposed gold miners had higher prevalence of detectable ANA and ANoA and higher titers of ANA and ANoA as compared to diamond and emerald miners with no occupational mercury exposure. Also, mercury-exposed gold miners with detectable ANA or ANoA in serum had significantly higher concentrations of pro-inflammatory cytokines IL-1beta, TNF-alpha, and IFN-gamma in serum as compared to the diamond and emerald miners. This study provides further evidence that mercury exposure may lead to autoimmune dysfunction and systemic inflammation in affected populations.

Occupational health, mercury exposure, and environmental justice: learning from experiences in Tanzania

Mercury is a potent neurotoxin that is used by poverty-driven miners to extract gold in more than 50 countries. This article examines efforts of the United Nations to address occupational health and environmental justice amid these challenges, focusing on a 3-year campaign in one of the fastest-growing mining communities in Tanzania. By providing an integrative analysis of environmental health risks, labor practices, public health policies, and drivers of social inequity and marginalization, this study highlights the need for interdisciplinary public health approaches that support community development by strengthening local capacities. It illustrates why, to ensure that the needs of vulnerable populations are met, environmental justice and public health paradigms have to expand beyond the conventionally narrow attention paid to toxic exposure and emissions issues.

Human mercury exposure and adverse health effects in the Amazon: a review

This paper examines issues of human mercury (Hg) exposure and adverse health effects throughout the Amazon region. An extensive review was conducted using bibliographic indexes as well as secondary sources. There are several sources of Hg (mining, deforestation, reservoirs), and exposure takes place through inhalation or from fish consumption. There is a wide range of exposure, with mean hair-Hg levels above 15 microg/g in several Amazonian communities, placing them among the highest reported levels in the world today. Dietary Hg intake has been estimated in the vicinity of 1-2 microg/kg/day, considerably higher than the USEPA RfD of 0.1 microg/kg/day or the World Health Organization recommendation of 0.23 microg/kg/day. Neurobehavioral deficits and, in some cases, clinical signs have been reported both for adults and children in relation to Hg exposure in several Amazonian countries. There is also some evidence of cytogenetic damage, immune alterations, and cardiovascular toxicity. Since fish provide a highly nutritious food source, there is an urgent need to find realistic and feasible solutions that will reduce exposure and toxic risk, while maintaining healthy traditional dietary habits and preserving this unique biodiversity.

Socioeconomic consequences of mercury use and pollution

In the past, human activities often resulted in mercury releases to the biosphere with little consideration of undesirable consequences for the health of humans and wildlife. This paper outlines the pathways through which humans and wildlife are exposed to mercury. Fish consumption is the major route of exposure to methylmercury. Humans can also receive toxic doses of mercury through inhalation of elevated concentrations of gaseous elemental mercury. We propose that any effective strategy for reducing mercury exposures requires an examination of the complete life cycle of mercury. This paper examines the life cycle of mercury from a global perspective and then identifies several approaches to measuring the benefits of reducing mercury exposure, policy options for reducing Hg emissions, possible exposure reduction mechanisms, and issues associated with mercury risk assessment and communication for different populations.