Mercury use in artisanal small-scale gold mining threatens human health: measures to describe and reduce the health risk

Steckling N. Mercury use in artisanal small-scale gold mining threatens human health: measures to describe and reduce the health risk. Bielefeld: Universität Bielefeld; 2016.**Background:** Mercury is used in more than 70 countries to extract gold in artisanal small-scale gold mining (ASGM). The application of mercury is simple and plays a key role in the livelihood for more than 16 million gold miners. Mercury is added to the crushed ore and builds an amalgam with the gold it contains. The amalgam is then smelted, the mercury evaporates, and gold remains. The amalgam smelting is the main source of mercury exposure in ASGM. ASGM is the largest anthropogenic source of global mercury pollution. The toxic metal poses a risk to the health of both the miners involved and the residents in the area, who do not work in ASGM. Mercury can be detected in critical quantities in the human bodies of both groups. The local threat aside, the mercury released is also of global concern due to its high transportability and persistence in the environment as well as its tendency to bioaccumulate. Mercury is neurotoxic and its harmful effects on the development of unborn children and infants are particularly alarming. Describing and reducing the health risk posed by the mercury used in ASGM are urgently needed measures, as demanded in the 2013 agreed Minamata Convention on Mercury. Objective and research questions: The overall objective of this thesis is to apply public health measures to describe the health risk due to the use of mercury in selected ASGM areas and to test the feasibility of a mercury-free extraction procedure using borax to reduce the risk. The main research question is: How to describe and reduce the human health risk of mercury used in ASGM? Four subquestions regard (I) the relevance of addressing different subgroups when attempting to describe and reduce the human health risk of mercury used in ASGM, (II) the mercury body burden in ASGM, (III) the health burden due to mercury exposure in ASGM, and (IV) a means of reducing the health risk due to the use of mercury in ASGM. The response to the research questions is included in the present synopsis and based on five published and peer-reviewed scientific papers. **Materials and methods:** This thesis comprises different materials and methods. The literature used was searched by applying narrative and systematic approaches (papers P1, P2, P3, P4, P5). P1 is a narrative review about children’s health and exposure to mercury. In P2 and P3, the mercury body burden was determined using human biomonitoring (HBM) data collected in Mongolia in 2008 (P2) and Zimbabwe in 2004 and 2006 (P3) and compared with the German HBM values, HBM I and II (P2, P3). Health effects attributable to mercury were analyzed for the sample from Zimbabwe using anamnestic data, neuropsychological testing, and clinical examination (P3). Cases of chronic mercury intoxication were identified and the sample prevalence determined and extrapolated to all of Zimbabwe (P3). The environmental burden of disease (EBD) was quantified in terms of disability-adjusted life years (DALYs) including primary, secondary, and modeled data (P3). Disease-specific and generic health state descriptions were developed which could be used to derive disability weights (DWs) for disease stages of the intoxication due to exposure to mercury in gold mining. Information about the health-related quality of life (HRQoL) and a comprehensive list of possible symptoms were gathered by expert elicitation. The list of symptoms was supplemented by a systematic literature search (P4). The feasibility of a mercury-free gold extraction method using borax was tested in a field project in Kadoma, Zimbabwe, in 2013 (P5). **Results:** Children are particularly vulnerable to mercury exposure. They might be exposed directly and indirectly to it from ASGM while several subgroups (pregnant and breastfeeding women, parents working as miners, etc.) play a role in the children’s exposure (P1). In the districts Bornuur and Jargalant, Mongolia, a sample of women of child-bearing age involved in mining or living in mining areas (P2), and in Kadoma, Zimbabwe (P3), a sample of adult and child male and female miners were investigated. Both samples showed raised mercury concentrations in human specimens above health-related exposure limit values. The analyses of health data showed a higher frequency of possibly mercury-related health effects in miners in comparison to controls (P3). The EBD in male and female adult and child miners in Zimbabwe in 2004 was high (total of 95,400 DALYs, 8 DALYs/1,000 population) while subgroup analyses identified males, particularly male children and young male adult workers, as the group with the highest burden (P3). The HRQoL of individuals with chronic metallic mercury vapor intoxication (CMMVI) caused by mercury exposure from ASGM can be substantially reduced by a number of health symptoms of varying severities (P4). In field testing, the application of a mercury-free gold extraction method using borax has been considered as feasible, what could reduce the health risk posed by mercury in ASGM (P5). **Discussion:** This thesis provides evidence to improve the understanding of the human health risk due the use of mercury in ASGM. The human health risk posed by mercury in ASGM can be described as considerable, subgroup-specific, and, indeed, reducible. The health risk is considerable given the particular risk of children (P1), the high mercury concentrations in specimens obtained from miners and not occupationally exposed residents in ASGM areas (P2, P3), the high prevalence of intoxications and EBD of miners (P3), the extensive range of possible health symptoms, and the reduced HRQoL due to mercury intoxication (P4). The health risk can be considered subgroup-specific for several reasons. These include the particular risk to children and the influence which the behavior of other subgroups has on the children’s exposure (P1), the human body burden detectable in miners and non-occupationally exposed residents in ASGM areas varying by sex and age (P2, P3), the prevalence of intoxications and EBD of intoxications in miners varying by sex and age (P3), and the extensive range of possible health symptoms which can but do not have to occur in individuals as a result of exposure to mercury (P3, P4). The health risk is reducible with regard to the fact that a mercury-free gold extraction method has been tested successfully (P5). Research of international literature reveals significant differences in mercury concentrations in human specimens of subgroups in ASGM areas. Combining HBM with health data is reasonable for identifying cases of chronic mercury intoxication, has also been done in samples of other countries. Based on the preliminary DALY estimates, chronic mercury intoxication from ASGM was integrated in the top 20 causes of the BoD in Zimbabwe in 2004 as estimated by the World Health Organization (WHO) in the GBD 2004 update. A national estimation of DALYs due the use of mercury in ASGM had not been investigated up to this point. Other DALY quantifications with focus on mercury are available, however, the research gaps for the use of mercury in ASGM (e.g., missing DWs) are mentioned in international literature. Results about the HRQoL of CMMVI enabled comparisons with the HRQoL of other health states investigated in other studies. The mercury-free gold extraction procedure using borax was identified as feasible in ASGM in Kadoma, Zimbabwe, and was also reported from other ASGM areas. However, a sustainable introduction needs follow-up implementation activi-ties. Further main limitations of this thesis are restricted literature search strategies, small sample sizes, and the reliance on assumptions and modeled data. The results of this thesis can be integrated into 8 of 9 steps of a human health risk analysis. Measures used to describe the risk should be applied in a health impact assessment (HIA) to monitor the success of a comprehensive introduction of a mercury-free extraction procedure. **Conclusions:** It is the conclusion of this thesis that the human health risk from mercury used in ASGM is considerable, subgroup-specific, and reducible. Various materials and methods were used, while some (e.g., estimation of DALYs and determination of HRQoL) had not been applied to this topic before. The relevance of different subgroups in the effort to describe and reduce the risk due to mercury from ASGM was identified. Some subgroups require attention most urgently either due to their particularly high vulnerability (fetuses and children), their influence on the exposure of others (e.g., pregnant women), or their particularly high EBD (young male gold miners). This thesis underlines the necessity to reduce the human health risk due to mercury in ASGM. The results of this thesis should be understood as an impetus to finding solutions for the continuing threat to human health from the use of mercury in ASGM

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

Aspectos Psicossociais, Estresse e Estilo de Vida em Portadores de Doença CardiovascularPsychosocial Aspects, Stress and Lifestyle in Bearers of Cardiovascular Disease

Esta pesquisa objetivou analisar o estresse emocional e o estilo de vida em indivíduos portadores de doenças cardiovasculares, quando da manifestação aguda da doença. Este foi um estudo de campo, com uma amostra constituída de 25 indivíduos, participantes do Programa de Prevenção e Reabilitação Cardíaca, do Núcleo de Cardiologia e Medicina do Exercício, da UDESC. Os resultados encontrados indicam que indivíduos que apresentam comportamento tipo A estão mais propensos a desenvolverem doenças cardiovasculares, demonstrando que antes da manifestação aguda da doença, viveram altos níveis de estresse emocional, tensão, ansiedade, competitividade e perfeccionismo. Estes indivíduos não relataram estratégias de controle do stress, sentindo-se muito afetados por problemas de difícil solução. Eles geralmente possuíam um estilo de vida sedentário e maus hábitos alimentares, caracterizado por uma dieta hipercalórica e alta ingestão de gorduras saturadas. Palavras-chave: Stress emocional. Estilo de vida. Doença cardiovascular. This research aimed at to analyze the emotional stress and the lifestyle in individuals bearers of cardiovascular diseases, when of the sharp manifestation of the disease. This was a field study, with a constituted sample of 25 individuals, participants of the Program of Prevention and Heart Rehabilitation, of the Nucleus of Cardiology and Medicine of the Exercise, of UDESC. The found results indicate that individuals that present behavior type A are prone to develop cardiovascular diseases, demonstrating that before the sharp manifestation of the disease, they lived high levels of emotional stress, tension, anxiety, competitiveness and perfectionism. These individuals didn't tell strategies of control of the stress, feeling very affected for problems of difficult solution. They usually possessed a sedentary lifestyle and bad alimentary habits, characterized by a diet caloric and high ingestion of saturated fats.Key words: Emotional stress. Lifestyle. Cardiovascular diseases

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

Alterações na composição química do solo e no desenvolvimento inicial de plântulas de milho ocasionadas pela aplicação superficial de calcário e fertilizantes fosfatados

Despite the small mobility of phosphates and liming, addition of these materials on the soil surface, without incorporation, has often increased crop yield. However, it is unknown the behavior of plant roots developed in a soil with only a thin layer chemically ameliorated, as well as the result of combining large amounts of lime and phosphates on P availability. This study was carried out to evaluate the effect of surface addition of lime and phosphates on maize dry mattert yield as well as on some soil and root parameters. Lime rates applied on the soil surface were equivalents to 0, 1/8, 1/4 e 1/2 of the quantity required to raise the pH-H2O of a 17 cm soil layer depth to 6.0 (5.0 g kg-1), which was also added but incorporated into the soil. Phosphorus was applied at rate of 100 mg P kg-1, as diammonium phosphate (DAP) or triple superphosphate (TSF). The experiment was set in a greenhouse using pots containing 5.0 kg (dry base) of an acid Oxisol where five maize plants were grown for 26 days after emergence. Addition of lime on the soil surface improved the chemical characteristics of the most superficial soil layer (0 to 2.5 cm). Increases on maize dry matter yield due to surface liming occurred only with the smallest lime rate, which had the same efficiency of the integral rate incorporated into the soil. Liming increased P uptake regardless of rates applied or forms of addition, but had no effect on root parameters probably due to the high P values in the soil. The smaller values for soil P caused by diammonium phosphate, relatively to triple superphosphate, had no negative effect on root parameters, P uptake, or dry matter yield of 26-days old maize plants. Therefore, in absence of water deficit, addition of lime and P fertilizers over the soil surface improves the initial growth of maize plants.Apesar da baixa mobilidade dos fosfatos e do calcário, a aplicação desses insumos na superfície do solo, sem incorporação, tem freqüentemente aumentado o rendimento vegetal. Desconhece-se, entretanto, o comportamento das raízes em relação à existência de apenas uma camada superficial de solo melhorada quimicamente, assim como da combinação de grandes quantidades de calcário e fosfatos na disponibilidade de P. O presente trabalho objetivou avaliar o rendimento de matéria seca de milho e alterações em atributos de solo e de raízes ocasionados pela combinação de doses de calcário e de fertilizantes fosfatados, ambos aplicados sobre a superfície de um Latossolo Bruno ácido, em casa-de-vegetação. As quantidades de calcário aplicadas na superfície equivaleram a 0, 1/8, 1/4 e 1/2 da dose necessária para elevar o pH-H2O de uma camada de 17 cm para 6,0 (5,0 g kg-1), a qual foi também utilizada, porém incorporada ao solo. O P foi aplicado na dose de 100 mg kg-1, na forma de fosfato diamônio (DAP) e de superfosfato triplo (SFT). Foram cultivadas cinco plantas de milho por vaso (5,0 kg de solo, base seca) durante 26 dias após a germinação. A adição de calcário sobre a superfície do solo ocasionou melhorias significativas na composição química da camada mais superficial do solo (0 a 2,5 cm). O benefício da calagem superficial no rendimento de matéria seca da parte aérea do milho somente ocorreu com a menor dose aplicada (1/8 de SMP), cujo efeito foi semelhante ao proporcionado pela dose integral (1,0 SMP) incorporada. A calagem aumentou a absorção de P, independente da dose ou da forma de aplicação, porém não influenciou nenhum atributo radicular provavelmente devido ao alto teor de P no solo. Os menores valores de P no solo ocasionados pela adição de DAP relativamente ao SFT não se refletiram negativamente nos parâmetros radiculares, na absorção de P, nem tampouco no rendimento de matéria seca, nos primeiros 26 dias de desenvolvimento do milho. Não havendo déficit hídrico, portanto, a adição de calcário e de P sobre a superfície do solo melhora o desenvolvimento inicial das plântulas de milho

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

BACKGROUND Artisanal small-scale gold mining (ASGM) is the world's largest anthropogenic source of mercury emission. Gold miners are highly exposed to metallic mercury and suffer occupational mercury intoxication. The global disease burden as a result of this exposure is largely unknown because the informal character of ASGM restricts the availability of reliable data. OBJECTIVE To estimate the prevalence of occupational mercury intoxication and the disability-adjusted life years (DALYs) attributable to chronic metallic mercury vapor intoxication (CMMVI) among ASGM gold miners globally and in selected countries. METHODS Estimates of the number of artisanal small-scale gold (ASG) miners were extracted from reviews supplemented by a literature search. Prevalence of moderate CMMVI among miners was determined by compiling a dataset of available studies that assessed frequency of intoxication in gold miners using a standardized diagnostic tool and biomonitoring data on mercury in urine. Severe cases of CMMVI were not included because it was assumed that these persons can no longer be employed as miners. Cases in workers' families and communities were not considered. Years lived with disability as a result of CMMVI among ASG miners were quantified by multiplying the number of prevalent cases of CMMVI by the appropriate disability weight. No deaths are expected to result from CMMVI and therefore years of life lost were not calculated. Disease burden was calculated by multiplying the prevalence rate with the number of miners for each country and the disability weight. Sensitivity analyses were performed using different assumptions on the number of miners and the intoxication prevalence rate. FINDINGS Globally, 14-19 million workers are employed as ASG miners. Based on human biomonitoring data, between 25% and 33% of these miners-3.3-6.5 million miners globally-suffer from moderate CMMVI. The resulting global burden of disease is estimated to range from 1.22 (uncertainty interval [UI] 0.87-1.61) to 2.39 (UI 1.69-3.14) million DALYs. CONCLUSIONS This study presents the first global and country-based estimates of disease burden caused by mercury intoxication in ASGM. Data availability and quality limit the results, and the total disease burden is likely undercounted. Despite these limitations, the data clearly indicate that mercury intoxication in ASG miners is a major, largely neglected global health problem

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

Utilização do método de Papadakis na melhoria da qualidade experimental de ensaios com soja

The objective of this work was to verify the modifications in statistical analysis regarding the assumption fulfillment and the different precision indicators which can be attributed to the application of the Papadakis method, in the analysis of soybean grain yield experiments. The results of soybean yield of 226 trials of genotype competition, performed in a design of complete randomized blocks, were used. For each experiment, the assumptions were checked for: the variance analyses, hypothesis tests and other analysis to identify its precision. In order to verify the profit in precision, the same data were analyzed using the Papadakis method. The assumptions were adequate for both analysis types. The mean of Fasoulas differentiation index increased from 5 to 12.43, for homogeneous blocks, and to 13.85, for heterogeneous blocks. The determination coefficient, adequate to classify the precision of the experiments, was approximately 10% higher, when the Papadakis method was used, regardless the efficiency of block use. The efficiency of the Papadakis method does not depend on the efficiency of the blocks, and allows an improvement of the indicators of experimental precision.O trabalho teve como objetivo verificar as modificações na análise estatística, em relação ao atendimento aos pressupostos do modelo matemático e aos diferentes indicadores de precisão, que podem ser atribuídas à aplicação do método de Papadakis, na análise dos ensaios de competição de genótipos de soja. Foram usados os resultados da produção de grãos de soja de 226 ensaios de competição de genótipos, executados no delineamento de blocos completos ao acaso. Em cada ensaio, foram realizados: a verificação dos pressupostos, a análise da variância, os testes de hipóteses e outras estatísticas para identificação da precisão. Para verificar os ganhos em precisão, os mesmos dados foram analisados pelo método de Papadakis. Os pressupostos não foram violados em nenhum dos dois métodos de análise. A média do índice de diferenciação de Fasoulas aumentou de 5 para 12,43, em blocos homogêneos, e para 13,85, em blocos heterogêneos. O coeficiente de determinação, adequado para a classificação de precisão de experimentos, foi aproximadamente 10% superior com o uso do método de Papadakis, independentemente da eficiência do uso de blocos. A eficiência do método de Papadakis independe da eficiência do uso dos blocos e permite melhorias nos indicadores de precisão experimental

Disability Weights for Chronic Mercury Intoxication Resulting from Gold Mining Activities: Results from an Online Pairwise Comparisons Survey

Steckling N, Devleesschauwer B, Winkelnkemper J, et al. Disability Weights for Chronic Mercury Intoxication Resulting from Gold Mining Activities: Results from an Online Pairwise Comparisons Survey. International Journal of Environmental Research and Public Health. 2017;14(1): 57