Mercury contamination of two e-waste recycling sites in Ghana: an investigation into mercury pollution at Dagomba Line (Kumasi) and Agbogbloshie (Accra)

This study investigated mercury pollution at two e-waste recycling sites in Ghana-Dagomba Line in Kumasi and Agbogbloshie in Accra. A total of 129 soil samples taken at 100 m and 50 m resolutions, respectively, for Dagomba Line and Agbogbloshie, were analysed for mercury using a Zeeman atomic absorption spectrometry. Mercury concentrations from the recycling sites (ranging from 0.11 to 7.57 mg/kg Dagomba Line, and 0.01-4.36 mg/kg at Agbogbloshie) were significantly higher than that of the surrounding areas (0.01-0.17 mg/kg in Kumasi and 0.01-2.18 mg/kg in Accra) and unpolluted control sites (0.05 mg/kg in Kumasi and 0.02 mg/kg in Accra). The dismantling sites at both locations had the highest mercury concentrations. Furthermore, the concentrations were significantly higher at the Dagomba Line site in Kumasi than at Agbogbloshie, even though the Dagomba Line site is relatively recent. The mercury concentrations at both sites exceeded the pollution prevention and abatement level of 0.1 mg/kg. However, the estimated human health risk showed no potential human health effects. Moreover, the mercury concentrations in water and sediment (0.12-7.69 ng/L and 0.02-0.28 ng/L for Dagomba Line and Agbogbloshie, respectively) were below the US EPA standards. Findings from this study show that e-waste recycling can contaminate the topsoil with mercury, irrespective of the scale of the activity.

Mercury (Hg) use and pollution assessment of ASGM in Ghana: challenges and strategies towards Hg reduction

Reduction or possible elimination of Hg from artisanal and small-scale gold mining (ASGM) is one of the main goals of the Minamata Convention on Mercury, which has been signed by many countries involved in ASGM, including Ghana. This article provides a recent overview of ASGM gold production and Hg use in Ghana. In addition, in order to highlight the impacts of Hg use in Ghana, a review was conducted on research studies investigating Hg pollution in waterbodies, soils, fish, and humans caused by ASGM over the past two decades. The continued use of Hg in Ghana's growing ASGM sector has resulted in reportedly high Hg levels found in water, sediments, crops, and miners, which exceed international guidelines. A subsequent ASGM ban and increased monitoring of illegal mining activities in Ghana have not ultimately been successful at significantly reducing Hg use and its associated impacts caused by rampant use in the country. Moreover, Hg alternatives in the ASGM sector are limited in Ghana, with little funding, support, education, and training in place to promote their implementation. As gold produced by ASGM continues to increase annually, clear policy reforms targeting Hg use are vitally needed, as well as efficient strategies to remediate Hg-contaminated areas.

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.

Recent advances in understanding and measurement of mercury in the environment: Terrestrial Hg cycling

This review documents recent advances in terrestrial mercury cycling. Terrestrial mercury (Hg) research has matured in some areas, and is developing rapidly in others. We summarize the state of the science circa 2010 as a starting point, and then present the advances during the last decade in three areas: land use, sulfate deposition, and climate change. The advances are presented in the framework of three Hg "gateways" to the terrestrial environment: inputs from the atmosphere, uptake in food, and runoff with surface water. Among the most notable advances: These and other advances reported here are of value in evaluating the effectiveness of the Minamata Convention on reducing environmental Hg exposure to humans and wildlife.

Mercury Exposure Among Artisanal and Small-Scale Gold Miners in Four Regions in Uganda

BACKGROUND

Artisanal and small-scale gold mining is a human health concern, especially in low-income countries like Uganda due to the use of mercury (Hg) in the mining process.

OBJECTIVE

The aim of the present study was to assess Hg exposure among artisanal and small-scale gold miners in Uganda through biologic monitoring parameters and Hg-related clinical manifestations.

METHODS

A cross-sectional study was conducted from June to July 2018 among 183 miners from Ibanda (Western region), Mubende (Central region), Amudat (Karamoja region) and Busia (Eastern region) in Uganda. An interviewer-administered questionnaire and health assessment were used to collect socio-demographic, exposure and self-reported Hg poisoning symptoms. In addition, 41 urine, 41 blood and 26 environment samples were assessed. Descriptive statistics, Kruskal-Wallis test and Wilcoxon signed-rank test for comparison of Hg levels in urine and blood among miners were performed while logistic regression was used to assess associations between exposure and Hg poisoning-related symptoms.

RESULTS

The miners ranged from 15 to 65 years old and were primarily male (72.6%). The majority (73.3%) had worked directly with Hg for an average duration of 5.3 years. Symptoms associated with working directly with Hg included chest pain (odds ratio (OR)=9.0, confidence interval (CI)=3.3 to 24.6), numbness (OR=8.5, CI=2.1 to 34.4), back pain (OR=6.2, CI= 2.2 to 17.5), fatigue and stress (OR=5.4, 2.0 to CI=14.9), headache (OR=4.7, CI=1.9 to 11.3), dizziness (OR=3.8, CI=1.5 to 9.7) joint pain (OR=3.2, CI=1.3 to 8.3) and respiratory problems (3.2, 1.0 to 10.1). Statistically significant differences in Hg levels with p-values less than 0.05 were observed across district, gender and type of work. Mubende had the highest blood and urine levels (136 μg/l and 105.5 μg/l) in comparison with Busia (60 μg/l and 70.6 μg/l) and Ibanda (43 μg/l and 58 μg/l). Females (84.7 μg/l), panners (109 μg/l) and those with knowledge of occupational health and safety measures (95.6 μg/l) reported higher levels of Hg in urine. The average levels of Hg in water and soil samples were 23.79 μg/l and 0.21 μg/l, respectively.

CONCLUSIONS

Variation in Hg levels were attributed to varied duration of exposure across geographical sites. There was considerable exposure to Hg as indicated by both clinical manifestations and biologic parameters among miners in Uganda with Hg in urine exceeding the recommended thresholds.

PARTICIPANT CONSENT

Obtained.

ETHICS APPROVAL

Ethical approval was obtained from the Makerere University School of Health Science Institutional Review Board (reference number SHSREC REF 2018-2019) and Uganda National Council for Science and Technology (reference number SS 4577).

COMPETING INTERESTS

The authors declare no competing financial interests.

Mercuric pollution of surface water, superficial sediments, Nile tilapia (Oreochromis nilotica Linnaeus 1758 [Cichlidae]) and yams (Dioscorea alata) in auriferous areas of Namukombe stream, Syanyonja, Busia, Uganda

The mercury content and the contamination characteristics of water, sediments, edible muscles of a non-piscivorous fish (Oreochromis nilotica Linnaeus 1758 [Cichlidae]) and yams (Dioscorea alata) from Namukombe stream in Busia gold district of Uganda were evaluated. Human health risk assessment from consumption of contaminated fish and yams as well as contact with contaminated sediments from the stream were performed. Forty-eight (48) samples of water (n = 12), sediments (n = 12), fish (n = 12) and yams (n = 12) were taken at intervals of 10 m from three gold recovery sites located at up, middle and down sluices of the stream and analyzed for total mercury (THg) using US EPA method 1631. Results (presented as means  ±  standard deviations) showed that water in the stream is polluted with mercury in the range of < detection limit to 1.21  ±  0.040 mg/L while sediments contain mean THg from < detection limit to 0.14  ±  0.040 ugg^-1. Mean THg content of the edible muscles of O. nilotica ranged from < detection limit to 0.11 ± 0.014 ugg^-1while D. alata contained from < detection limit to 0.30  ±  0.173 ugg^-1mean THg. The estimated daily intake ranged from 0.0049 ugg^-1day^-1 to 0.0183 ugg^-1day^-1 and 0.0200 ugg^-1day^-1 to 0.0730 ugg^-1day^-1 for fish consumed by adults and children respectively. The corresponding health risk indices ranged from 0.0123 to 0.0458 and 0.0500 to 0.1830. Estimated daily intake was from 0.0042 ugg^-1day^-1 to 0.1279 ugg^-1day^-1 and 0.0130 ugg^-1day^-1 to 0.3940 ugg^-1day^-1 for D. alata consumed by adults and children respectively. The health risk indices recorded were from 0.011 to 0.320 and 0.033 to 0.985 for adults and children respectively. The mean THg content of the sediments, edible muscles of O. nilotica and D. alata were within acceptable WHO/US EPA limits. About 91.7% of the water samples had mean THg above US EPA maximum permissible limit for mercury in drinking water. Consumption of D. alata grown within 5 m radius up sluice of Namukombe stream may pose deleterious health risks as reflected by the health risk index of 0.985 being very close to one. From the pollution and risk assessments, mercury use should be delimited in Syanyonja artisanal gold mining areas. A solution to abolish mercury-based gold mining in the area needs to be sought as soon as possible to avert the accentuating health, economic and ecological disaster arising from the continuous discharge of mercury into the surrounding areas. Other mercury-free gold recovering methods such as use of borax, sluice boxes and direct panning should be encouraged. Waste management system for contaminated wastewater, used mercury bottles and tailings should be centralized.

Impact of recent artisanal small-scale gold mining in Senegal: Mercury and methylmercury contamination of terrestrial and aquatic ecosystems

In Senegal, the environmental impact of artisanal small-scale gold mining (ASGM) using mercury (Hg) is poorly documented despite its intensification over the past two decades. We report here a complete dataset including the distribution and speciation of Hg in soil, sediment, and water in pristine and ASGM impacted sites of the Gambia River ecosystem (Kedougou region - eastern Senegal). Selective extraction showed that soils surrounding ASGM activities were contaminated with elemental Hg [Hg(0)] at concentrations up to 3.9 mg kg^-1. In the Gambia River, high total Hg (THg: 1.16 ± 0.80 mg kg^-1) and methylmercury (MeHg: 3.2 ± 2.3 ng g^-1) were also measured in sediment samples collected at ASGM sites. Along the stream, THg concentrations in sediment decrease with distance from the ASGM sites, while those of methylmercury increase downstream. The study of THg and MeHg partitioning between filtered surface water and suspended particles demonstrate that particulate transport is responsible for the downstream dissemination of the Hg contamination from ASGM sites. Sedimentation of fine particles enriched in Hg downstream ASGM sites likely favors MeHg production and accumulation in sediment. Although elemental Hg is weakly labile, surface soil erosion may also provide important and long-term Hg inputs to downstream aquatic ecosystems, where it can be oxidized and methylated. Finally, the dissemination of THg and MeHg downstream from the ASGM sites in the Gambia River may constitute a long-term source of contamination and can have a large scale impact on the aquatic ecosystem through biomagnification.

Understanding the Social Context of the ASGM Sector in Ghana: A Qualitative Description of the Demographic, Health, and Nutritional Characteristics of a Small-Scale Gold Mining Community in Ghana

This descriptive paper describes factors related to demographics and health in an artisanal and small-scale gold mining (ASGM) community in Ghana’s Upper East Region. Participants (n = 114) were surveyed in 2010 and 2011, adapting questions from the established national Demographic Health Survey (DHS) on factors such as population characteristics, infrastructure, amenities, education, employment, maternal and child health, and diet. In the study community, some indicators of household wealth (e.g., radios, mobile phones, refrigerators) are more common than elsewhere in Ghana, yet basic infrastructure (e.g., cement flooring, sanitation systems) and access to safe water supplies are lacking. Risk factors for poor respiratory health, such as cooking with biomass fuel smoke and smoking tobacco, are common. Certain metrics of maternal and child health are comparable to other areas of Ghana (e.g., frequency of antenatal care), whereas others (e.g., antenatal care from a skilled provider) show deficiencies. Residents surveyed do not appear to lack key micronutrients, but report lower fruit and vegetable consumption than other rural areas. The results enable a better understanding of community demographics, health, and nutrition, and underscore the need for better demographic and health surveillance and data collection across ASGM communities to inform effective policies and programs for improving miner and community health.

Integrated Assessment of Artisanal and Small-Scale Gold Mining in Ghana-Part 2: Natural Sciences Review

This paper is one of three synthesis documents produced via an integrated assessment (IA) that aims to increase understanding of artisanal and small-scale gold mining (ASGM) in Ghana. Given the complexities surrounding ASGM, an integrated assessment (IA) framework was utilized to analyze socio-economic, health, and environmental data, and co-develop evidence-based responses with stakeholders. This paper focuses on the causes, status, trends, and consequences of ecological issues related to ASGM activity in Ghana. It reviews dozens of studies and thousands of samples to document evidence of heavy metals contamination in ecological media across Ghana. Soil and water mercury concentrations were generally lower than guideline values, but sediment mercury concentrations surpassed guideline values in 64% of samples. Arsenic, cadmium, and lead exceeded guideline values in 67%, 17%, and 24% of water samples, respectively. Other water quality parameters near ASGM sites show impairment, with some samples exceeding guidelines for acidity, turbidity, and nitrates. Additional ASGM-related stressors on environmental quality and ecosystem services include deforestation, land degradation, biodiversity loss, legacy contamination, and potential linkages to climate change. Though more research is needed to further elucidate the long-term impacts of ASGM on the environment, the plausible consequences of ecological damages should guide policies and actions to address the unique challenges posed by ASGM.