High human exposure to cobalt and other metals in Katanga, a mining area of the Democratic Republic of Congo

Metal-bearing airborne particles from mining activities: A review on their characteristics, impacts and research perspectives

The presence of various contaminants in airborne dusts from metal mining sites poses obvious risks to human health and the environment. Yet, few studies have thoroughly investigated the properties of airborne particles in terms of their morphology, size distribution and chemical composition, that are associated with health effects around mining activities. This review presents the most recent knowledge on the sources, physicochemical characteristics, and health and environmental risks associated with airborne dusts from various mining and smelting operations. The literature reviewed found only one research on atmospheric dust associated with hydrometallurgical plants compared to a larger number of pyrometallurgical processes/smelters studies. In addition, there are relatively few works comparing the distribution of metals between the fine and coarse size fractions around mining sites. Our analysis suggests that (i) exposure pathways of metal(loid)s to the human body are defined by linking concentration data in human biosamples and contaminated samples such as soils, drinking water and food, and (ii) chitosan and its derivatives may serve as an environmentally friendly and cost-effective method for soil remediation, with removal rates for metal(loid)s around 70-95 % at pH 6-8, and as dust suppressants for unpaved roads around mining sites. The specific limit values for PM and metal(loid)s at mining sites are not well documented. Despite the health risks associated with fine particles around mining areas, regulations have tended to focus on coarse particles. While some air quality agencies have issued regulations for occupational health and safety, there is no global alignment or common regulatory framework for enforcement. Future research priorities should focus on investigating PM and secondary inorganic aerosols associated with hydrometallurgical processes and dust monitoring, using online metal(loid)s analysers to identify the driving parameters in the deposition and resuspension process.

From Critical Raw Materials to Circular Raw Materials

This perspective addresses the key challenge of advancing the use of Critical Raw Materials (CRMs) and proposes a transition towards circular raw material management. In the context of our current economy, the unsustainable consumption, environmental degradation, geopolitical risks, and economic vulnerabilities associated with CRMs highlight the limitations in ensuring long-term CRM availability, emphasizing the environmental, social, and economic implications. In response, this perspective underlines a multifaceted technological approach to mitigate CRM criticality, focusing on reducing CRM use, substituting CRMs with less critical materials, and enhancing recovery and recycling processes, with Design for Circularity as the most impactful solution. The latter advocates for a paradigm shift in product design and material utilization, emphasizing principles like modular design, product life extension, and the transition from product ownership to service models. Such a holistic approach is not only crucial for sustainable CRM management, but is also key to fostering a resilient and low-carbon economy.

Assessing bioavailability risks of heavy metals in polymetallic mining regions: a comprehensive analysis of soils with varied land uses

To accurately assess the bioavailability risk of heavy metals (HMs) in a representative polymetallic mining region, we undertook an exhaustive analysis of Cu, Pb, Ni, Co, Cd, Zn, Mn, and Cr in soils from diverse land-use types, encompassing agricultural, forest, residential, and mining areas. We employed speciation analysis methods and a modified risk assessment approach to ascertain potential ecological threats posed by the HMs. Our findings reveal that both the total potential ecological risk and the modified bioavailability risks are most pronounced in the soil of the mining area. The modified bioavailability threats are primarily caused by Pb, Ni, Cd, and Co. Although the total potential ecological risk of Cu is high in the local soil, the predominance of its stable forms reduces its mobility, thereby mitigating its detrimental impact on the ecosystem. Additionally, medium modified bioavailability risks were identified in the peripheries of agricultural and forest areas, potentially attributable to geological processes and agricultural activities. Within the urban district, medium risks were observed in residential and mining areas, likely resulting from mining, metallurgy, industrial operations, and traffic-related activities. This study provides critical insights that can assist governmental authorities in devising targeted policies to alleviate health hazards associated with soils in polymetallic mining regions.

Application of soil amendments to reduce the transfer of trace metal elements from contaminated soils of Lubumbashi (Democratic Republic of the Congo) to vegetables

The extraction of copper and cobalt from mines has led to the contamination of agricultural soils by trace metal elements (TMEs) (e.g. Cu: 204 to 1355 mg/kg). The mining industry is one of the sources of metal discharges into the environment, contributing to water, soil, and air contamination and causing metabolic disorders in the inhabitants of the city of Lubumbashi (R.D. Congo). This study assessed the effectiveness of organocalcareous soil improvers applied to TME-contaminated soils to reduce their transfer to plants. Following a factorial design, increasing doses of organic soil improvers (chicken droppings and sawdust) and agricultural lime were applied to the soils of three market gardens (high, medium, and low Cu contamination). The experiment was monitored for 60 days. Soil physicochemical properties (pH, TOC, and total and available copper, cobalt, lead, cadmium, and zinc (mg/kg)) were determined for the three gardens and in the vegetable biomass. The daily consumption index of the vegetables was determined based on total TME content. The results show that organocalcareous soil improvers did not promote plant growth and survival on soils with high and medium levels of copper contamination. However, on soils with low copper content, organocalcareous soil improvers improved germination and plant survival and reduced the transfer of metals from the soil to the plants. The best germination and plant survival rates were obtained with the lightly contaminated market garden. In addition, the organo-limestone amendments applied to the soils slightly increased the soil pH from acidic to slightly acidic, with pH values ranging from (5.43 ± 0.07 to 7.26 ± 0.33). The daily vegetable consumption index obtained for cobalt in the low-contaminated garden ranged from (0.029 to 0.465 mg/60 kg/day), i.e. from 0.5 to 8.45 times higher than the FAO/WHO limit, unlike the other trace metals (Cd, Cu and Pb) for which the daily consumption index found was lower than the FAO/WHO limit. Organocalcareous soil improvers can only be applied to soils with low levels of TME contamination, but for soils with medium to high levels of metal contamination, new soilless production techniques such as hydroponics or bioponics are needed.

Simultaneous removal of Cd(II) and phosphate by nanoscale zero-valent iron from solution: Co-sorption and implication of corrosion

Nanoscale zero-valent iron (nZVI) has been extensively utilized in environmental remediation, but its reactivity in the presence of co-contaminants requires further investigation for effective application in complex environments. Here, we conducted batch removal experiments to systematically investigate the co-removal behaviors of Cd(II) and phosphate by nZVI. Results showed that nZVI can synergistically remove Cd(II) and phosphate in solution, with the removal efficiency of Cd(II) and phosphate in the binary system being approximately 2 and 5 times higher than those in the single system, respectively. Sequential removal experiments combined with characterization analysis revealed the co-sorption of Cd(II) and phosphate onto the corrosion product of nZVI mainly by forming the ternary complexes (≡Fe-P-Cd). The Fe(OH)2 formed as the initial nZVI corrosion product provides numerous active sites for immobilization of Cd(II) and phosphate. Such effective co-sorption of Fe(OH)2 inhibits its subsequent phase transformation to Fe3O4. Overall, our work sheds light on how nZVI, Cd(II), and phosphate interact in solution as well as highlights the influence of phase transformation on co-removal, which can broaden the potential applications of nZVI in the practical environment.

Occupational, environmental, and toxicological health risks of mining metals for lithium-ion batteries: a narrative review of the Pubmed database

BACKGROUND

The global market for lithium-ion batteries (LIBs) is growing exponentially, resulting in an increase in mining activities for the metals needed for manufacturing LIBs. Cobalt, lithium, manganese, and nickel are four of the metals most used in the construction of LIBs, and each has known toxicological risks associated with exposure. Mining for these metals poses potential human health risks via occupational and environmental exposures; however, there is a paucity of data surrounding the risks of increasing mining activity. The objective of this review was to characterize these risks.

METHODS

We conducted a review of the literature via a systematic search of the PubMed database on the health effects of mining for cobalt, lithium, manganese, and nickel. We included articles that (1) reported original research, (2) reported outcomes directly related to human health, (3) assessed exposure to mining for cobalt, lithium, manganese, or nickel, and (4) had an available English translation. We excluded all other articles. Our search identified 183 relevant articles.

RESULTS

Toxicological hazards were reported in 110 studies. Exposure to cobalt and nickel mining were most associated with respiratory toxicity, while exposure to manganese mining was most associated with neurologic toxicity. Notably, no articles were identified that assessed lithium toxicity associated with mining exposure. Traumatic hazards were reported in six studies. Three articles reported infectious disease hazards, while six studies reported effects on mental health. Several studies reported increased health risks in children compared to adults.

CONCLUSIONS

The results of this review suggest that occupational and environmental exposure to mining metals used in LIBs presents significant risks to human health that result in both acute and chronic toxicities. Further research is needed to better characterize these risks, particularly regarding lithium mining.

Protective effect of cholecalciferol against cobalt-induced neurotoxicity in rats: ZO-1/iFABP, ChAT/AchE and antioxidant pathways as potential therapeutic targets

Cobalt (Co) toxicity has been reported to produce central nervous system and gastrointestinal abnormalities. This study assessed the therapeutic effect of cholecalciferol (Cho) supplementation against damages caused by sub-acute (14-day) cobalt chloride (CoCl2) exposure in the brain and intestines. Thirty-five male Wistar rats were divided equally into five groups: Group I (control) received no treatment; Group II received oral CoCl2 (100 mg/kg) only; Groups III, IV, and V received 1000, 3000 and 6000 IU/kg of cholecalciferol, respectively by oral gavage, and concurrently with CoCl2. Cobalt-treated rats showed neuronal vacuolation and presence of pyknotic nuclei in the cerebral cortex and hippocampus, depletion of Purkinje cells in the cerebellum, as well as inflammation and congestion in the intestinal mucosa. Cobalt also increased brain and intestinal hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations, while simultaneously reducing glutathione (GSH) content, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities. Further, CoCl2 induced increases in brain acetylcholinesterase (AchE) activity and serum zonulin (ZO-1) levels. Conversely, Cho administration suppressed CoCl2-induced damages in the brain and intestines by reducing lipid peroxidation and increasing the activities of antioxidant enzymes. Remarkably, Cho produced stimulation of brain choline acetyltransferase (ChAT) and suppression of AchE activity, along with dose-dependent reduction in serum levels of ZO-1, intestinal fatty acid-binding protein (iFABP) and nitric oxide. In conclusion, the protective role of cholecalciferol against cobalt-induced toxicity occurred via modulation of cholinergic, intestinal permeability and antioxidant pathways. The results may prove significant in the context of the role of gut-brain connections in neuroprotection.

Cottage industry as a source of high exposure to lead: A biomonitoring study among people involved in manufacturing cookware from scrap metal

In low-income countries, a widespread but poorly studied type of cottage industry consists of melting scrap metal for making cookware. We assessed the exposure to lead (Pb) among artisanal workers, and their families, involved in manufacturing cookware from scrap metal. In a cross-sectional survey, we compared artisanal cookware manufacturing foundries with carpentry workshops (negative controls) and car battery repair workshops (positive controls), all located in residential areas, in Lubumbashi (DR Congo). We collected surface dust in the workspaces, and blood and urine samples among workers, as well as residents living in the cookware workshops. Trace elements were quantified in the samples by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In surface dust, median Pb concentrations were higher in cookware foundries (347 mg/kg) than in carpentries (234 mg/kg) but lower than in battery repair workshops (22,000 mg/kg). In workers making the cookware (n = 24), geometric mean (GM) Pb blood cencentration was 118 μg/L [interquartile range (IQR) 78.4-204], i.e. nearly twice as high as among carpenters [60.2 μg/L (44.4-84.7), n = 33], and half the concentration of battery repair workers [255 μg/L (197-362), n = 23]. Resident children from the cookware foundries, had higher urinary Pb [6.2 μg/g creatinine (2.3-19.3), n = 6] than adults [2.3 (2.2-2.5), n = 3]. Our investigation confirms the high Pb hazard linked to car battery repair and reveals a high exposure to Pb among artisanal cookware manufacturers and their families, especially children, in residential areas of a city in a low-income country.

Hypoxaemia and risk of asphyxia during underground work in artisanal cobalt mines

BACKGROUND

More than half the cobalt needed for vehicle electrification originates from the southern part of the Democratic Republic of the Congo (DRC), with a substantial part being extracted by artisanal miners.

AIMS

To investigate oxygen saturation during underground work among cobalt artisanal miners.

METHODS

In a field survey, we measured oxygen saturation (SpO2) and heart rate by pulse oximetry in 86 miners from two underground mines and 24 miners from a surface mine at four different time points: before descent into the mine (T1), at 50 minutes in the mine (T2), upon leaving the shaft (T3), and 10 minutes after having left the mine (T4).

RESULTS

Miners working underground (-36 to -112 meters) were somewhat older (34.8 ± 6.7 years) than those working in the surface mine (32.0 ± 6.5 years), and they worked more hours daily (12.6 ± 1.2 hours) than controls (9.0 ± 0.0 hours). All participants had SpO2 >95% at T1 and T4. At T2, SpO2 dropped below 93% and 80% in 35% and 10% underground miners, respectively; SpO2 was still <93% at T3 in 13%. SpO2 remained stable among surface miners. Later, we showed that underground ambient oxygen levels decreased well below 21% in several pits.

CONCLUSIONS

Pulse oximetry revealed relevant hypoxaemia during underground work in a substantial proportion of artisanal miners. Such hypoxaemia without evidence of underlying cardiovascular disease is indicative of low ambient oxygen, due to insufficient mine ventilation. This may cause deaths from asphyxia. The hazards of low ambient oxygen in artisanal mines must be prevented by appropriate technical measures ensuring the supply of sufficient fresh air.

Transplacental transfer of cobalt: Evidence from a study of mothers and their neonates in the African Copperbelt

BACKGROUND

Transfer of the trace metal cobalt (Co) from mother to foetus has not been documented in populations with high environmental exposure to Co, as is the case in the African Copperbelt mining region. We analysed data obtained from 246 mother-infant pairs included (at delivery) in a previously published case-control study on birth defects, done in Lubumbashi (Democratic Republic of Congo) between March 1, 2013, and Feb 28, 2015.

METHODS

Co was measured by Inductively Coupled Plasma Mass Spectrometry in maternal blood, maternal urine, umbilical cord blood and placental tissue, as available.

RESULTS

The Co concentrations [geometric mean (GM) with interquartile range (IQR)] in maternal blood (GM 1.77 µg/L, IQR 1.07-2.93) and urine (GM 7.42 µg/g creatinine, IQR 4.41-11.0) were highly correlated (Spearman r = 0.71, n = 166; p < 0.001) and considerably higher than reference values determined for general populations elsewhere in the world. The concentrations of Co in umbilical cord blood (GM 2.41 µg/L) were higher (Wilcoxon test, p < 0.001) than in maternal blood (GM 1.37 µg/L), with a correlation between both values (Spearman r = 0.34; n = 127, p < 0.001). Co concentrations in placental tissue (geometric mean 0.02 µg/g wet weight) correlated with concentrations in maternal blood (Spearman r = 0.50, n = 86, p < 0.001) and in neonatal blood (Spearman r = 0.23, n = 83, p = 0.039).

CONCLUSION

This first study of maternal and neonatal Co concentrations in the African Copperbelt provides strong evidence of a high transfer of Co from mother to foetus.

Bioaccessible metals in dust materials from non-sulfide Zn deposit and related hydrometallurgical operation

Mining and processing of ores in arid (desert) areas generates high amounts of dust, which might be enriched in potentially harmful elements. We studied dust fractions of ores, soils, and technological materials from mining and related hydrometallurgical operation at former Skorpion Zinc non-sulfide Zn deposit in southern Namibia (closed and placed under maintenance in 2020). Chemical and mineralogical investigation was combined with oral bioaccessibility testing of fine dust fractions (<48 μm and <10 μm) in simulated gastric fluid (SGF) to assess potential risk of intake of metallic contaminants (Cd, Cu, Pb, Zn) for staff operating in the area. The bulk metals concentrations were largely variable and ranked as follows: soils < tailings ≪ Skorpion ores < imported ores and dross used for feed ore blending. Maximum contaminant concentrations in the original granular materials were 927 mg Cd/kg, 9150 mg Cu/kg, 50 g Pb/kg and 706 g Zn/kg, respectively, and generally increased as a function of decreasing grain size. The highest bioaccessible concentrations of Cd and Pb yielded imported ores from Taiwan and Turkey and, together with the milled dross, these samples also exhibited the highest Zn bioaccessibilities. The exposure estimates calculated for a worker (weighing 70 kg) in this mining/ore processing operation at a dust ingestion rate of 100 mg/day indicated that most dust samples (soils, tailings, Skorpion ores) exhibited metals intake values far below tolerable daily intake limits. The overall health risk was limited in all mining and ore processing areas except for the ore blending area, where imported ores and recycled dross enriched in bioaccessible Cd, Pb and/or Zn were used for the ore blending. Safety measures required by the mine operator (wearing of masks by the operating staff) helped to prevent the staff's exposure to potentially contaminated dust even in this blending ore area.

Human health risk assessment due to mercury use in gold mining areas in the Ecuadorian Andean region

Mining activity drives economic development and has established itself as one of the main industrial spheres globally. However, illegal, and artisanal gold mining, which uses mercury (Hg), is a major source of global pollution. Hg is highly toxic and persistent in the environment, affecting human health and the ecosystem. The objective of this research is to; (a) analyze Hg concentrations in surface waters of nine provinces of the Andean region of Ecuador and compare them with the maximum permissible limits of Ecuadorian regulations, and (b) evaluate the health risk of people exposed to waters with high Hg content through residential and recreational scenarios. In this study, 147 water samples from rivers and streams were analyzed. The results revealed worrying levels of Hg, especially in the provinces of Azuay and Loja where Hg values of up to 0.0913 mg/L and 0.0387 mg/L, respectively, were detected. In addition, it was found that 45% of the samples did not meet the water quality criteria for the preservation of aquatic life, which represents a severe risk to the ecosystem. The probabilistic risk analysis yielded values that exceeded the acceptable exposure limit for adults and children in residential settings in Azuay and Loja, while in the recreational scenario the safe exposure limit was exceeded for both receptors only in the province of Azuay. The elevated presence of Hg in the provinces, mainly in Azuay and Loja, possibly related to illegal gold mining activity, represents a threat to water quality and aquatic life in the Andean region of Ecuador. Children are especially vulnerable, and effective regulation is required to ensure the safety of the population. This study provides valuable information for decision makers regarding the risk associated with Hg exposure in areas of mining activity in the Ecuadorian Andean region. In addition, it can contribute to the development of policies and strategies to control contamination in mining environments and protect human and environmental health in the region.

Accumulation of Trace Metals in Fruits from Mango and Syzygium guineense Growing in Residential Households from a Contaminated District of Lubumbashi (DR Congo): Is Fruit Consumption at Risk?

Copper smelting has been a source of soil contamination with trace metals in Penga Penga (Lubumbashi). The residents are exposed to trace metal ingestion, and planting trees is challenging in such soil conditions. Nevertheless, planting trees in former household dumps or using various types of amendments has allowed the provisioning of fruits in a few residences. From the perspective of scaling up the process, a survey has been conducted with the aim of assessing the effectiveness of the planting processes on the trace metal content in fruits and leaves of Mangifera indica L. and Syzygium guineense (Willd) DC. Samples were collected from residential households in Penga Penga and Kalebuka (a non-polluted suburb). The bioconcentration factor (BCF) and the safe weekly consumption (SWC) were calculated for each species. The results showed higher values of total and soluble concentrations of Cu, Pb, and Zn in the rhizosphere of the two species in Penga Penga. Metal concentrations were higher in the fruits and leaves from Penga Penga, with 47% of samples above the FAO and WHO thresholds (vs. 18.5% in Kalebuka). The BCF values were below 1, demonstrating the effectiveness of the process in reducing the translocation of metals to leaves and fruits. Recommendations from the SWC limit Pb consumption to 9 kg for mango flesh and Cd consumption to 6.6 kg for S. guineense fruits in Penga Penga (vs. 78 kg and 68 kg in Kalebuka). Finally, the results of this study provide interesting lessons for the scaling up and technical itinerary of planting trees in Penga Penga.

Sequestration of cobalt and nickel by biofilm forming bacteria isolated from spent nuclear fuel pool water

In the current study, six bacterial types, isolated from spent nuclear fuel (SNF) pool facility, were investigated for their ability to sequester heavy metals (cobalt and nickel). Biofilm formation by the six bacterial isolates, viz., Bacillus subtilis, Staphylococcus species, Staphylococcus arlettae, Staphylococcus epidermidis, Staphylococcus auricularis, and Chryseobacterium gleum, were assayed, and they were found to have significant biofilm forming property. Their biofilms were characterised using confocal scanning laser microscopy, and their potential to accumulate Co²⁺ and Ni²⁺ from bulk solutions was analysed with respect to time. A comparative assessment of bioaccumulation capacity was done using biofilms, planktonic cells, and live vs dead cells. The strains accumulated Co²⁺ and Ni²⁺ in the range of 4 × 10^-4 to 1 × 10^-5 g/mg of cell biomass. It is interesting to note that dead biomass also showed significant removal of the two metal ions, suggesting an alternative process for metal removal. This study suggests that hostile environments can be a repertoire of putative bacterial species with potential heavy metals and other contaminants remediation properties.

Reference intervals for cd, hg, Mn and Pb in the general children population (3-14 years) of Kinshasa, Democratic Republic of Congo (DRC) between June 2019 and June 2020

The reference intervals (RIs), proposed by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and the International Union of Pure and Applied Chemistry (IUPAC), were derived for Cd, Hg, Mn and Pb in the blood and urine of the children population living in Kinshasa (n = 200, aged 3-14 years with 97 girls). Levels of metals were measured using coupled plasma mass (ICP-MS). In blood, the proposed RIs [P5-P95 (GM)] were 0.022-1.112 μg/L (0.074), 35.69-144.50 μg/L (71.43), 0.060 to 1.161 μg/L (0.208) and 6.597-15.740 μg/L (9.882) for Cd, Pb, Hg and Mn, respectively. Urinary levels [(P5-P95 (GM)] were 0.082-1.530 μg/L (0.366) for Cd, 1.827-18.500 μg/L (5.458) for Pb, 0.323-1.953 μg/L (0.709) for Hg and 0.070 to 1.703 μg/L (0.186) for Mn. As compared to the CDC updated blood Pb reference value (35 μg/L), Pb levels remain higher of public health concern. Cd and Mn levels were similar to those found in the same city in 2015 and databases involving non-occupationally exposed populations from other countries. Hg levels significantly lower than those found in the same city in 2015, probably due to exclusion criteria of metal exposure applying in the present survey (occupationally exposed to the studied metals, smoking habits, amalgam tooth fillings, fish consumption habit more than one time per week, etc.). These background metal exposures will be useful for future occupational and/or environmental surveys as well as undertaking a reliable regulation of chemical exposure in Kinshasa via a national HBM program.

“They polluted our cropfields and our rivers, they killed us”: Farmers’ complaints about mining pollution in the Katangese Copperbelt

The adverse impacts of mining industries on human health, local biodiversity, and food security are well-documented in the Katangese Copperbelt. However, farmers' perceptions of pollution and their struggles to obtain compensation for the externalities of mining industries are little addressed in scientific and public debates. Drawing on interviews with smallholder farmers, local civil society archives, oral histories, and analysis of satellite images, this article presents a case of farmers of Mulungwishi Valley whose fields and waterways were polluted by mining effluents. While 25% of respondent farmers argued that they had noticed pollution from the beginning of the 2000s, testimonies from civil society, customary authorities, and farmers concurred that the phenomenon has increased since 2010. Particularly between 2013 and 2014, the death of fish in the Mulungwishi River, the coloration of the water, the spread of mining effluents across the valley, and crop failure raised concerns and despair among farmers. Remarkable changes in land cover and use were noticeable. Since a joint impact assessment in 2014 by la Générale des Carrières et des Mines' (Gécamines) experts and farmers, civil society unsuccessfully continued a struggle to obtain compensation for about 2570 farmers affected by pollution. Despite an absolute silence of the polluter, 88% of these farmers insisted on the depollution of the valley and were willing to accept, if it was offered, financial compensation of $US 2820 per farmer. The decade-long persistence of farmers in asserting these requests debunks the view of farmers as passive or not concerned about environmental pollution. This article will be helpful for stakeholders (victims and polluters) to find common ground when resolving this environmental issue that has resulted in socio-economic difficulties beyond the valley.

The local health impacts of natural resource booms

This paper uses novel micro-data on natural resources and administrative health data in Brazil to study how economic booms in minerals affect health at birth. By implementing a reduced-form estimation of shift-share research designs, the identification strategy relies on the exogeneity of global commodity prices to municipality-specific health outcomes. I find that, following changes in international prices, municipalities with historically more endowments have a higher number of premature births and births with low Appearance, Pulse, Grimace, Activity, Respiration scores. The impacts are primarily driven by metallic minerals. Instead, industrial minerals do not appear to have any effect on birth outcomes. Even though booms in metallic minerals generate benefits through resource windfalls-by increasing wealth and generating economic opportunities-the investigation of mechanisms reveals that they also result in costs-due to pollution-which seem to prevail. Hence, some metallic minerals remain a curse more than a blessing.

Contaminant Binding and Bioaccessibility in the Dust From the Ni-Cu Mining/Smelting District of Selebi-Phikwe (Botswana)

We studied the dust fractions of the smelting slag, mine tailings, and soil from the former Ni-Cu mining and processing district in Selebi-Phikwe (eastern Botswana). Multi-method chemical and mineralogical investigations were combined with oral bioaccessibility testing of the fine dust fractions (<48  and <10 μm) in a simulated gastric fluid to assess the potential risk of the intake of metal(loid)s contaminants. The total concentrations of the major contaminants varied significantly (Cu: 301-9,600 mg/kg, Ni: 850-7,000 mg/kg, Co: 48-791 mg/kg) but were generally higher in the finer dust fractions. The highest bioaccessible concentrations of Co, Cu, and Ni were found in the slag and mine tailing dusts, where these metals were mostly bound in sulfides (pentlandite, pyrrhotite, chalcopyrite). On the contrary, the soil dusts exhibited substantially lower bioaccessible fractions of these metals due to their binding in less soluble spinel-group oxides. The results indicate that slag dusts are assumed to be risk materials, especially when children are considered as a target group. Still, this exposure scenario seems unrealistic due to (a) the fencing of the former mine area and its inaccessibility to the local community and (b) the low proportion of the fine particles in the granulated slag dump and improbability of their transport by wind. The human health risk related to the incidental ingestion of the soil dust, the most accessible to the local population, seems to be quite limited in the Selebi-Phikwe area, even when a higher dust ingestion rate (280 mg/d) is considered.

Landscape Analysis of Cobalt Mining Activities from 2009 to 2021 Using Very High Resolution Satellite Data (Democratic Republic of the Congo)

The cobalt mining sector is well positioned to be a key contributor in determining the success of the Democratic Republic of the Congo (DRC) in meeting the Sustainable Development Goals (SDGs) by 2030. Despite the important contribution to the DRC’s economy, the rapid expansion of mining operations has resulted in major social, health, and environmental impacts. The objective of this study was to quantitatively assess the cumulative impact of mining activities on the landscape of a prominent cobalt mining area in the DRC. To achieve this, an object-based method, employing a support vector machine (SVM) classifier, was used to map land cover across the city of Kolwezi and the surrounding mining areas, where long-term mining activity has dramatically altered the landscape. The research used very high resolution (VHR) satellite imagery (2009, 2014, 2019, 2021) to map the spatial distribution of land cover and land cover change, as well as analyse the spatial relationship between land cover classes and visually identified mine features, from 2009 to 2021. Results from the object-based SVM land cover classification produced an overall accuracy of 85.2–90.4% across the time series. Between 2009 and 2021, land cover change accounted to: rooftops increasing by 147.2% (+7.7 km2); impervious surface increasing by 104.7% (+3.35 km2); bare land increasing by 85.4% (+33.81 km2); exposed rock increasing by 56.2% (+27.46 km2); trees decreasing by 4.5% (−0.34 km2); shrub decreasing by 38.4% (−26.04 km2); grass and cultivated land decreasing by 27.1% (−45.65 km2); and water decreasing by 34.6% (−3.28 km2). The co-location of key land cover classes and visually identified mine features exposed areas of potential environmental pollution, with 91.6% of identified water situated within a 1 km radius of a mine feature, and vulnerable populations, with 71.6% of built-up areas (rooftop and impervious surface class combined) situated within a 1 km radius of a mine feature. Assessing land cover patterns over time and the interplay between mine features and the landscape structure allowed the study to amplify the findings of localised on-the-ground research, presenting an alternative viewpoint to quantify the true scale and impact of cobalt mining in the DRC. Filling geospatial data gaps and examining the present and past trends in cobalt mining is critical for informing and managing the sustainable growth and development of the DRC’s mining sector.

Impacts of Trace Metals Pollution of Water, Food Crops, and Ambient Air on Population Health in Zambia and the DR Congo

Zambia and the DR Congo are situated in the central African Copperbelt, which is part of the Lufilian geological structure arc stretching over from Kolwezi in Katanga Province in the DRC to Luanshya in Copperbelt Province in Zambia. The area has large copper-cobalt deposits of which the extraction causes severe ecosystem damage due to pollution of water, food crops, and the ambient air negatively impacting population health. Contamination of drinking water for domestic use and foods (cereals, roots and tubers, vegetables, and fruits) was determined by assessing the contents of trace metals including Mn, Ni, Pb, Zn, Co, As, U, Cd, and Cu and through a questionnaire for environmental damage. Food samples were analyzed by inductively coupled argon plasma/optical emission spectroscopy (ICP-OES), while water and urine samples were analyzed by inductively coupled argon plasma mass spectrometry (ICP-MS). Concentrations of Ni, Pb, and Cd were higher in almost all food crops, although Cu was more in samples of Cucurbita maxima and Amaranthus hybridus. Mean contents (μg/L) of Mn, Zn, Cd, Pb, and U were, respectively, 5,454.6, 2552.2, 138.7, 39.7, 2361.1, and 21.4 in the DRC and 108.9, 543.3, 0.3, 0.2, 1.5, and 0.5 in Zambia, being significantly higher and always far above World Health Organization maximum limits in the DRC. Urine samples taken only from the DRC contained trace metals with children's samples being more contaminated than adult ones. Our results conclusively echo the most critical challenges of toxic pollutants causing numerous health issues among the population. Given an outcry among households adjacent to mines about land degradation and food spoilage, and health problems over years, joint efforts are needed from public and private sectors for stringent mining exploitation monitoring for sustainable governance to protect the environment and ensure food and nutrition safety, and population well-being in Zambia and the DR Congo.

Quantification and Simulation of Landscape Anthropization around the Mining Agglomerations of Southeastern Katanga (DR Congo) between 1979 and 2090

In Southeastern Katanga, mining activities are (in)directly responsible for deforestation, ecosystem degradation and unplanned building densification. However, little is known about these dynamics at the local level. First, we quantify the landscape anthropization around four agglomerations of Southeastern Katanga (Lubumbashi, Likasi, Fungurume and Kolwezi) in order to assess the applicability of the Nature–Agriculture-Urbanization model based on the fact that natural landscapes are replaced by anthropogenic landscapes, first dominated by agricultural production, and then built-up areas. Secondly, we predict evolutionary trends of landscape anthropization by 2090 through the first-order Markov chain. Mapping coupled with landscape ecology analysis tools revealed that the natural cover that dominated the landscape in 1979 lost more than 60% of its area in 41 years (1979–2020) around these agglomerations in favor of agricultural and energy production, the new landscape matrix in 2020, but also built-up areas. These disturbances, amplified between 2010 and 2020, are more significant around Lubumbashi and Kolwezi agglomerations. Built-up areas which spread progressively will become the dominant process by 2060 in Lubumbashi and by 2075 in Kolwezi. Our results confirm the applicability of the Nature–Agriculture-Urbanization model to the tropical context and underline the urgency to put in place a territorial development plan and alternatives regarding the use of charcoal as a main energy source in order to decrease the pressure on natural ecosystems, particularly in peri-urban areas.

Biochemical and reproductive biomarker analysis to study the consequences of heavy metal burden on health profile of male brick kiln workers

The present study aims to assess the effect of a heavy metal burden on general health, biochemical parameters, an antioxidant enzyme, and reproductive hormone parameters in adult male brick kiln workers from Pakistan. The study participants (n = 546) provided demographic data including general health as well as body mass index. Blood was collected to quantitatively assess hematological, biochemical, and reproductive hormone parameters as well as heavy metal concentrations using both atomic absorption spectroscopy (AAS) and particle-induced X-ray emission (PIXE). The data showed that 10% of the brick kiln workers were underweight and 10% obese (P = 0.059), with workers also reporting multiple health issues. Heavy metal concentrations utilizing AAS revealed significantly (p = 0.000) higher levels of cadmium, chromium, and nickel, while PIXE detected more than permissible levels of Si, P, S, Cl, K, Ca, Zn, Ti (p = 0.052), Mn (p = 0.017), Fe (p = 0.055), Co (p = 0.011), Ni (p = 0.045), and Cu (p = 0.003), in the blood of kiln workers. Moreover, a significant increase in platelet count (P = 0.010), a decrease in sodium dismutase levels (p = 0.006), a major increase in reactive oxygen species (p = 0.001), and a reduction in protein content (p = 0.013) were evident. A significant increase in cortisol levels (p = 0.000) among the workers group was also observed. The concentration of LH and FSH increased significantly (p = 0.000), while that of testosterone decreased (p = 0.000) in the worker group compared with controls. A significant inverse relationship was found between cortisol, LH (r =  - 0.380), and FSH (r =  - 0.946), while a positive correlation between cortisol and testosterone was also evident (r = 0.164). The study concludes that increased heavy metal burden in the blood of brick kiln workers exposes them to the development of general and reproductive health problems due to compromised antioxidant enzyme levels, increased oxidative stress conditions, and a disturbing reproductive axis.

Metal biomonitoring using fractioned dust to investigate urinary and oxidative stress biomarkers among occupationally exposed chromite mine workers

Exposure to heavy metals has been associated with the generation of reactive oxygen species (ROS) among exposed individuals in occupational and environmental settings. Dust is considered a significant contributor to airborne metal exposure, and previous data suggest that their levels in dust may vary based on its particle sizes. However, no biomonitoring study has been reported so far to address the metal-induced oxidative stress using different dust fractions, particularly in occupational settings. We designed a systematic cross-sectional study involving 110 chromite mine workers stratified into loaders (n = 28), extractors (n = 47) and operators (n = 35), and controls (n = 30) to find out the association between dust-bound metal exposure and oxidative stress using urinary creatinine-adjusted metal level as a biomarker of metal exposure. Results suggested elevated urinary levels of Cr 51.34 ± 8.6 along with Pb 34.29 ± 4.39, Cd 21.1 ± 2.6, and Ni 18.98 ± 3.01 µg/g creatinine in exposed (extractor group) workers. Correlating metal levels with oxidative stress revealed elevated malondialdehyde (MDA) levels of 62.28 ± 5.52 nM/dl among the extractors showing high levels of lipid peroxidation. Furthermore, blood superoxide dismutase (SOD) was also found significantly correlated (P = 0.000) with urinary toxic metal levels among exposed workers. We report the association between metal exposure and oxidative stress in exposed mining workers that may give rise to workers' susceptibility towards genetic and non-genetic health implications. The current study emphasized on the need for exposure control measures in the chromite ore mining activity areas.

Assessment of Street Tree Diversity, Structure and Protection in Planned and Unplanned Neighborhoods of Lubumbashi City (DR Congo)

Street trees are always considered a vital part of urban green infrastructure in urbanized areas through mitigating the negative effects caused by urbanization taking part in human well-being. However, little is still known about their diversity, structure and protection, mostly in Lubumbashi city in the Democratic Republic of the Congo (DR Congo), where the pace of urbanization is not only rapid but also unplanned. In this study, using an inventory, we have characterized the diversity, structure and protection measures of street trees along a land-use planning gradient in Lubumbashi for both planned and unplanned neighborhoods. From the results, a total of 1596 trees were encountered, comprising 40 species, 33 genera and 17 families, mostly dominated by exotic species (65%). In addition, most of the studied trees (63%) belonged to four species only (Jacaranda mimosifolia, Leucaena leucocephala, Mangifera indica, and Acacia auriculiformis) with Leucaena leucocephala and Jacaranda mimosifolia being highly represented in unplanned and planned neighborhoods, respectively. The most abundant diameter classes in the planned neighborhoods were those with at most 10 cm against the classes larger than 50 cm in the planned neighborhoods. In both neighborhoods, trees with protection equipment represent less than 35%. Furthermore, in planned neighborhoods notably, nearly half of the observed equipment is in a good condition. Despite the benefits associated with street trees, there is a need to reduce the proportion of exotic tree species by planting native utilitarian tree species.

Heavy metals in fish nearby electronic waste may threaten consumer's health. Examples from Accra, Ghana

Electronic waste sites are rich in heavy metals contained in electronic and electric equipment waste and pose a risk of pollution if metals enter in the environment nearby. The Korle lagoon, located in the center of Accra, is receiving waste effluents from industries, households and the adjacent e-waste burning site Agbogbloshie which is the biggest in the country. Thus, the risk of heavy metal contamination of the water body and subsequent uptake in the aquatic food chain is particularly relevant. Small-scale fishing, not entering the commercial chain, occurs in the lagoon despite its consideration of biologically dead. We assessed if the exposure to heavy metals through these fish consumption is posing higher health risks than fish sold on Ghanaian markets. Using ICP-MS technology, we quantified concentrations of As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn in fish caught from the Korle Lagoon (Trachinotus ovatus, Mugil curema and Mugil cephalus) and compared them to fish from the Tema Newtown fishing market (Scomber colias, Pseudotolithus senegallus). Cobalt and lead concentrations, typical e-waste metals, were higher in fish from the Korle lagoon, even though they were of lower trophic level. Calculated risk indices revealed risk of elevated arsenic and mercury exposure, particularly through T. ovatus from the Korle lagoon, if consumed daily as it is common in the region. This study suggests the need of monitoring programs of Ghanaian catch, with a special focus in environmental risk areas like Korle lagoon to ensure human food safety.

Risk Analysis Approaches to Evaluating Health Impacts from Land-Based Pollution in Low- and Middle-Income Countries

Risk analysis offers a useful framework for evaluating and managing environmental health risks across different settings. In this Perspective, we question whether the principles and practice of risk analysis could be beneficial in the context of land-based pollution in low- and middle-income countries (LMICs) to better support risk-based decision making. Specifically, potential health and economic impacts from land-based pollution in LMICs has become an increasing issue of concern due to widespread environmental contamination from active and legacy operations, particularly informal activities that are becoming increasingly dispersed throughout communities, such as used lead acid battery recycling, artisanal and small-scale gold mining, and small-scale tanneries. However, the overall magnitude and scale of the public health problem arising from these sources remains highly uncertain and poorly characterized and cannot be compared to land-based pollution in high-income countries due to unique factors. This lack of knowledge has negatively affected the political priority and level of funding for risk mitigation actions targeting land-based pollution in these countries. Our primary objective is to raise further awareness of this emerging issue among risk analysts and decisionmakers and to advocate for more robust and focused research. Here, we highlight the types of industries and activities contributing to land-based pollution in LMICs and describe key findings and knowledge and data gaps that have hindered a fuller understanding of this issue. We also discuss how several risk assessment and risk management approaches might be useful in this resource-constrained context. We conclude that a combination of risk analysis approaches may be worthwhile, but more work is needed to determine which methods or tools will be most informative, technically feasible, and cost-effective for identifying, prioritizing, and mitigating land-based pollution in LMICs. Affected researchers, funding agencies, and local or national governments will need to work together to develop improved study designs and risk mitigation strategies.

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.

Concurrent Heavy Metal Exposures and Idiopathic Dilated Cardiomyopathy: A Case-Control Study from the Katanga Mining Area of the Democratic Republic of Congo

Blood and/or urine levels of 27 heavy metals were determined by ICPMS in 41 patients with dilated cardiomyopathy (DCM) and 29 presumably healthy subjects from the Katanga Copperbelt (KC), in the Democratic Republic of Congo (DRC). After adjusting for age, gender, education level, and renal function, DCM probability was almost maximal for blood concentrations above 0.75 and 150 µg/dL for arsenic and copper, respectively. Urinary concentrations above 1 for chromium, 20 for copper, 600 for zinc, 30 for selenium, 2 for cadmium, 0.2 for antimony, 0.5 for thallium, and 0.05 for uranium, all in μg/g of creatinine, were also associated with increased DCM probability. Concurrent and multiple exposures to heavy metals, well beyond permissible levels, are associated with increased probability for DCM. Study findings warrant screening for metal toxicity in case of DCM and prompt public health measures to reduce exposures in the KC, DRC.

Occupational rhinitis and asthma in bakers: a cross-sectional study in the former Katanga province of DR Congo

OBJECTIVE

Bakers are at high risk of rhinitis and asthma, but the prevalence of these occupational diseases is not well known in Sub-Saharan Africa. We investigated the prevalence of occupational rhinitis and asthma among industrial bakers in the former province of Katanga.

METHODS

In a cross-sectional study conducted in eight towns from October 2018 to September 2019, we included 276 male workers from 18 industrial bakeries and 113 male controls (35 butchers and 78 bread sellers), all nonsmokers. Participants replied to a validated questionnaire (European Community of Respiratory Health Survey II), administered face to face, and performed spirometry at the work place. In 15 bakers with symptoms of work-related asthma, records of self-measured peak expiratory flow (PEF) 4 times per day during 4 weeks were analyzed by the OASYS (Occupational Asthma System) protocol.

RESULTS

The bakers and controls did not differ by age (32.2 ± 7.3 y vs 32.8 ± 10.3 y). According to the questionnaire, work-related rhinitis and asthma were significantly more prevalent among bakers (31% and 5%, respectively) than among controls (2% and 0%, respectively). However, the groups did not differ significantly with regard to spirometric parameters. Based on PEF records, 10 out of 15 were positive for occupational asthma (OASYS score > 2.5), so the rate of occupational asthma was 3.6% in this study.

CONCLUSION

This first study in DR Congo demonstrates the existence of occupational rhinitis and asthma among industrial bakers in Katanga. Further epidemiological studies are needed to clarify the extent and risk factors of baker's asthma in the area. In the meantime, advocacy and implementation of appropriate occupational hygiene measures are warranted to protect bakery workers in DR Congo.

Oceanic karma? Eco-ethical gaps in African EEE metal cycle may hit back through seafood contamination

The increasing global demand for electric and electronic equipment (EEE) such as smartphones, tablets and electric car batteries has resulted in an increase in heavy metal releases to the environment at different steps during its manufacture (e.g. mining, extraction, production and e-waste). Some critical raw materials (CRMs) that supply the worldwide demand of technology are mainly sourced from Africa, but their resulting heavy metal pollution can reach citizens from other regions of the world through seafood caught in African waters, which would act as a vector. In this study, we review heavy metal contents in African fish and, as proof of concept, we analyse heavy metal content in three tuna species (Thunnus alalunga, T. albacares and T. obesus) caught in different regions inside the Sustainable Fisheries Partnership Agreements (SFPAs) by Spanish fleets and commercialised in Spain. Thunnus alalunga and T. albacares from African waters had higher concentrations of heavy metals (especially Hg but also As and Pb) in muscle than samples of the same species caught in other waters. Metal profiles in tunas from African waters were significantly correlated with those of continental and coastal fish from nearby areas impacted by mines and e-waste, as found in the literature review. Based on these results we identify research priorities that should be addressed in order to improve the social and environmental sustainability of EEE metal manufacture in Africa.

Geochemistry, Mineralogy and Microbiology of Cobalt in Mining-Affected Environments

Cobalt is recognised by the European Commission as a “Critical Raw Material” due to its irreplaceable functionality in many types of modern technology, combined with its current high-risk status associated with its supply. Despite such importance, there remain major knowledge gaps with regard to the geochemistry, mineralogy, and microbiology of cobalt-bearing environments, particularly those associated with ore deposits and subsequent mining operations. In such environments, high concentrations of Co (up to 34,400 mg/L in mine water, 14,165 mg/kg in tailings, 21,134 mg/kg in soils, and 18,434 mg/kg in stream sediments) have been documented. Co is contained in ore and mine waste in a wide variety of primary (e.g., cobaltite, carrolite, and erythrite) and secondary (e.g., erythrite, heterogenite) minerals. When exposed to low pH conditions, a number of such minerals are known to undergo dissolution, typically forming Co2+(aq). At circumneutral pH, such aqueous Co can then become immobilised by co-precipitation and/or sorption onto Fe and Mn(oxyhydr)oxides. This paper brings together contemporary knowledge on such Co cycling across different mining environments. Further research is required to gain a truly robust understanding of the Co-system in mining-affected environments. Key knowledge gaps include the mechanics and kinetics of secondary Co-bearing mineral environmental transformation, the extent at which such environmental cycling is facilitated by microbial activity, the nature of Co speciation across different Eh-pH conditions, and the environmental and human toxicity of Co.

Respiratory Health and Urinary Trace Metals among Artisanal Stone-Crushers: A Cross-Sectional Study in Lubumbashi, DR Congo

Background: Thousands of artisanal workers are exposed to mineral dusts from various origins in the African Copperbelt. We determined the prevalence of respiratory symptoms, pulmonary function, and urinary metals among artisanal stone-crushers in Lubumbashi. Methods: We conducted a cross-sectional study of 48 male artisanal stone-crushers and 50 male taxi-drivers using a standardized questionnaire and spirometry. Concentrations of trace metals were measured by Inductively Coupled - Plasma Mass Spectrometry (ICP-MS) in urine spot samples. Results: Urinary Co, Ni, As, and Se were higher in stone-crushers than in control participants. Wheezing was more prevalent (p = 0.021) among stone-crushers (23%) than among taxi-drivers (6%). In multiple logistic regression analysis, the job of a stone-crusher was associated to wheezing (adjusted Odds Ratio 4.45, 95% Confidence Interval 1.09–18.24). Stone-crushers had higher values (% predicted) than taxi-drivers for Forced Vital Capacity (105.4 ± 15.9 vs. 92.2 ± 17.8, p = 0.048), Forced Expiratory Volume in 1 Second (104.4 ± 13.7 vs. 88.0 ± 19.6, p = 0.052), and Maximum Expiratory Flow at 25% of the Forced Vital Capacity (79.0.1 ± 20.7 vs. 55.7 ± 30.1, p = 0.078). Conclusion: Stone-crushers were more heavily exposed to mineral dust and various trace elements than taxi-drivers, and they had a fourfold increased risk of reporting wheezing, but they did not have evidence of more respiratory impairment than taxi-drivers.

Agnathia otocephaly: A case from the Katanga Copperbelt

BACKGROUND

Agnathia otocephaly is a rare craniofacial malformation complex characterised by absent/hypoplastic mandible, abnormally positioned ears meeting at level of neck. Besides mutations in two genes, PRRX1 and OTX2, a teratogenic cause has been suggested. A higher risk of congenital malformations has been associated with paternal work in mining in the Democratic Republic of the Congo's part of the Copperbelt.

CASE

We studied a female neonate with a clinical diagnosis of agnathia otocephaly, stillborn in Lubumbashi in 2019. The child's father had been working as an artisanal mineworker at the time of conception.

RESULTS

Genetic analysis did not reveal a causal mutation. The concentrations of cobalt, arsenic cadmium, and uranium in cord blood of the infant were much higher than those of normal neonates from a previous study.

CONCLUSION

In the absence of identified genetic causes, we hypothesize this case of agnathia otocephaly was related to an exogenous cause, possibly the father's mining-related job.

Assessment of exposure to toxic metals and measures to address deficiency of essential trace elements in young children in rural Hubei, China

Children are exposed to toxic metals via diet and environment, which results in adverse health effects. Several trace elements are important for the nutritional status of children; however, little information is available for rural regions in Asia. Our goal was to assess the body burden of lead, cadmium, and aluminum (Al) as toxic metals and calcium (Ca), zinc, copper, selenium (Se), strontium, and boron as trace elements in children. Multiple environmental samples, including soil, dust, fine particulates, drinking water, and food, were collected for each family. A survey was conducted by trained personnel to record detailed information about children attending a rural school. Twenty-four-hour urine samples were collected. The levels of toxic and essential trace elements were determined by inductively coupled plasma mass spectrometry. We found that the daily intake of toxic metals was below the recommended maximum, suggesting low health risks. More attention should be given to the ingestion of Al by the hand-to-mouth pathway. Ca deficiency was discovered to be a serious health problem for rural children, with Ca inadequacies reaching 96%. The excessive intake of Se-rich products from industry suggests an increased risk of toxicity. This study highlights the health risks to children who live in rural regions and the importance of dietary Ca supplementation in school meals.

Metal mining and birth defects: a case-control study in Lubumbashi, Democratic Republic of the Congo

BACKGROUND

Widespread environmental contamination caused by mining of copper and cobalt has led to concerns about the possible association between birth defects and exposure to several toxic metals in southern Katanga, Democratic Republic of the Congo (DRC). We therefore aimed to assess the possible contribution of parental and antenatal exposure to trace metals to the occurrence of visible birth defects among neonates.

METHODS

We did a case-control study between March 1, 2013, and Feb 28, 2015, in Lubumbashi, DRC. We included newborns with visible birth defects (cases) and healthy neonates born in the same maternity ward (controls). Mothers were interviewed about potentially relevant exposures, including their partners' jobs. Various trace metals were measured by inductively coupled plasma mass spectrometry in maternal urine, maternal blood, umbilical cord blood, placental tissue, and surface dust at home. Multivariable logistic regression analyses were done to calculate adjusted odds ratios and their 95% CIs (CI).

FINDINGS

Our study included 138 neonates with visible birth defects (about 0·1% of the 133 662 births in Lubumbashi during the study period) and 108 control neonates. Potential confounders were similarly distributed between cases and controls. Vitamin consumption during pregnancy was associated with a lower risk of birth defects (adjusted odds ratio 0·2, 95% CI 0·1-0·5). Mothers having paid jobs outside the home (2·8, 1·2-6·9) and fathers having mining-related jobs (5·5, 1·2-25·0) were associated with a higher risk of birth defects. We found no associations for trace metal concentrations in biological samples, except for a doubling of manganese (Mn; 1·7, 1·1-2·7) and zinc (Zn; 1·6, 0·9-2·8) in cord blood. In a separate model including placentas, a doubling of Mn at the fetal side of the placenta was associated with an increased risk of birth defects (3·3, 1·2-8·0), as was a doubling of cord blood Zn (5·3, 1·6-16·6).

INTERPRETATION

To our knowledge, this is the first study of the effects of mining-related pollution on newborns in sub-Saharan Africa. Paternal occupational mining exposure was the factor most strongly associated with birth defects. Because neither Mn nor Zn are mined in Lubumbashi, the mechanism of the association between their increased prenatal concentrations and birth defects is unclear.

FUNDING

Flemish Interuniversity Council-University Development Cooperation, The Coalition of the North-South movement in Flanders 11.11.11.

Removal of Elemental Mercury from Flue Gas Using Cobalt-Containing Biomaterial Carbon Prepared from Contaminated Iris sibirica Biomass

Iris sibirica biomass (ISBM) used for cobalt (Co) pollution remediation was prepared by one-step pyrolysis and employed to remove elemental mercury (Hg0) from flue gas. Results showed that the ISBM pyrolyzed at 700 °C (ISBM700) exhibited good Hg0 removal performance (about 86%) at 150 °C. The existence of NO and O2 facilitated the removal of Hg0, while SO2 and water vapor inhibited it. Characterization analysis (including N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry) showed that ISBM700 has a relatively higher specific surface area, a quantity of lattice oxygen derived from well-dispersed amorphous-phase CoO x , and abundant oxygen functional groups. A Mars-Maessen mechanism is thought to be involved in the Hg0 removal process. The adsorbed Hg0 could be oxidized to HgO by the surface oxygen species derived from CoO x , and then, the consumed surface oxygen species can be replenished by O2. Therefore, the Co-contaminated I. sibirica biomass (CCIB) from phytoremediation could be utilized for Hg0 removal after being pyrolyzed instead of any chemical modification.

Reduced Cd, Pb, and As accumulation in rice (Oryza sativa L.) by a combined amendment of calcium sulfate and ferric oxide

A combined amendment (CF) consisting of 90% calcium sulfate (CaSO₄) and 10% ferric oxide (Fe₂O₃) was used to investigate the feasibility, active principles, and possible mechanisms of the immobilization of heavy metals in paddy soil. A soil incubation experiment, two consecutive pot trials, and a field experiment were conducted to evaluate the effectiveness and persistence of CF on metal(loid) immobilization. Soil incubation experiment results indicated that the application of CF significantly decreased the concentrations of cadmium (Cd), lead (Pb), and arsenic (As) in soil solution. CF treatments simultaneously reduced the accumulation of Cd, Pb, and As in two consecutive pot trials. The total Cd, Pb, and As concentrations in the rice grains were respectively 0.02, 2.08, and 0.62 mg kg^-1 in the control treatment in the second year, which exceeded the safety limits of contaminants in food products in China. However, a high amount of CF amendment (CF-H, 0.3%) effectively decreased Cd, Pb, and As by 75.0%, 75.5%, and 46.8%, respectively. Further, with the CF amendment, the bioavailable Cd and Pb in the soil and the accumulation of Cd, Pb, and As in rice grain in the field experiment were also significantly decreased. The concentrations of Cd, Pb, and As in grains were respectively 0.02, 0.03, and 0.39 mg kg^-1 in the control treatment in the field experiment, which decreased to 0.01, 0.01, and 0.22 mg kg^-1 with CF addition, suggesting that grains produced in the field could pose less health risk. In conclusion, these results implied that CF was an effective and persistent combined amendment to immobilize heavy metals in soil and thereby can reduce the exposure risk of metal(loid)s associated with rice consumption.

Erectile dysfunction and mining-related jobs: an explorative study in Lubumbashi, Democratic Republic of Congo

Introduction

The African Copperbelt is a site of intense artisanal and industrial mining and refining of copper and cobalt. Anecdotal reports of erectile dysfunction (ED) among mineworkers in the area led us to conduct an explorative study to investigate the possible association between ED and working in mining-related jobs.

Methods

We included 42 consecutive men (18–40 years) buying sildenafil (the active substance of Viagra) from a pharmacy located in a popular neighbourhood in Lubumbashi, and 42 age-matched (±2 years) men buying painkillers. All participants replied to questionnaires administered face-to-face to obtain sociodemographic data, including information on occupation, and a score of erectile function using the International Index of Erectile Function (IIEF6).

Results

The IIEF6 score (maximum 30) was lower among sildenafil-buyers (median 17, range 8–30) than among painkiller-buyers (median 30, range 17–30). The proportion of mining-related jobs was higher among sildenafil-buyers (19/42, 45%) than among painkiller-buyers (7/42, 17%), yielding an OR of 4.1 (95% CI 1.5 to 11.3; p=0.009). The proportion of mining-related jobs was higher among men with ED (defined as IIEF6 <26) (24/45, 54%) than among men without ED (2/39, 5%) (OR 21.1; 95% CI 4.5 to 98.4; p<0.001). Using a more stringent definition of ED (IIEF6 <22) gave similar results: 55% (20/36) of men with ED had a mining-related job versus 13% (6/48) of men without ED (OR 8.7; 95% CI 2.9 to 25.7; p=0.001).

Discussion

The findings of this preliminary study justify further epidemiological studies of the possible role of occupational exposures in the pathogenesis of male sexual dysfunction among miners and workers in the copper and cobalt industry.

Holoprosencephaly: A case series from an area with high mining-related pollution

BACKGROUND

The extraction and processing of copper and cobalt in the African Copperbelt in the Democratic Republic of Congo have led to substantial environmental pollution, causing concerns about possible adverse effects on human health, including birth defects.

CASES

We report three neonates with clinically diagnosed holoprosencephaly who were part of a case-control study performed in Lubumbashi between February 2013 and February 2015. One mother had a high concentration of uranium in urine, and high manganese concentrations were found in blood of another mother and in cord blood of one infant. Two of the three fathers had a mining-related job.

DISCUSSION

We hypothesize that these cases of holoprosencephaly were connected to mining-related pollution, possibly via epigenetic alterations induced by paternal occupational exposure to toxic metals.

Multiple exposure pathways and health risk assessment of heavy metal(loid)s for children living in fourth-tier cities in Hubei Province

In the past, most research focused on the children living near a typical contaminated area but ignored the health risks of children living in the fourth or fifth tier cities without typical contaminated sources. These cities are now facing a series of problems, such as serious environmental pollution, undeveloped health system and so on. Furthermore, the development of modern logistics for food delivery has altered lifestyles that directly impact diets and eating patterns. In this study, multiple exposure pathways and health risks of children to heavy metal(loid)s were studied based on questionnaire-based surveys and field sampling of soil, dust, fine particulates, drinking water and food. We found that Pb, Cd and Mn levels in environmental samples were very high indicating a serious pollution problem. Inhalation exposure via aerosol particles was the most important pathway and was greater than exposure by food ingestion. The hazard index for Mn via aerosol particles was >1 even at the 5th percentile and Mn levels in urine was 10 times higher than those of people living in typical contaminated areas. The total incremental lifetime cancer risk (ILCR) for all metal(loid)s was also higher than the threshold at the 95th percentile. This study highlights health risks to children living in fourth tier cities and the importance of air pollution control to protect heavy metal exposure for children.

Unprecedentedly High Dust Ingestion Estimates for the General Population in a Mining District of DR Congo

The mining of metals in low income countries is often associated with high exposure to dust that contributes to metal exposure. Here, dust ingestion estimates were made from fecal excretion of inert tracers with corrections for dietary contribution. The study took place in the cobalt mining area of Lubumbashi (DR Congo) and involved 120 nonoccupationally exposed participants in the dry season, with 51 of these being repeated in the rainy season. For each participant, duplicate meals (0-96 h), feces (24-120 h), and indoor/outdoor dust (<250 μm) were collected. The dust ingestion estimates (g day^-1) were derived from Nb, Ti, and V as best tracers and were 0.28 (geometric mean), 3.3 (mean), and 13 (P95); these values are almost a factor 10 above currently accepted estimates for the general population in high income countries. Mean dust ingestion in the dry season was twice that of the rainy season, and the P95s were significantly higher in children (3-15 years) than in male adults and toddlers; geophagy (>40 g day^-1) was suspected in three individuals. These data explain the previously reported extreme cobalt exposures in children and support the need to manage dust in the metal mining operations.

Synthesis of LiNi0.85Co0.14Al0.01O2 Cathode Material and its Performance in an NCA/Graphite Full-Battery

Nickel-rich cathode material, NCA (85:14:1), is successfully synthesized using two different, simple and economical batch methods, i.e., hydroxide co-precipitation (NCA-CP) and the hydroxides solid state reaction method (NCA-SS), followed by heat treatments. Based on the FTIR spectra, all precursor samples exhibit two functional groups of hydroxide and carbonate. The XRD patterns of NCA-CP and NCA-SS show a hexagonal layered structure (space group: R_3m), with no impurities detected. Based on the SEM images, the micro-sized particles exhibit a sphere-like shape with aggregates. The electrochemical performances of the samples were tested in a 18650-type full-cell battery using artificial graphite as the counter anode at the voltage range of 2.7–4.25 V. All samples have similar characteristics and electrochemical performances that are comparable to the commercial NCA battery, despite going through different synthesis routes. In conclusion, the overall results are considered good and have the potential to be adapted for commercialization.

Oral bioaccessibility of metal(loid)s in dust materials from mining areas of northern Namibia

Ore mining and processing in semi-arid areas is responsible for the generation of metal(loid)-containing dust, which is easily transported by wind to the surrounding environment. To assess the human exposure to dust-derived metal(loid)s (As, Cd, Cu, Pb, Sb, Zn), as well as the potential risks related to incidental dust ingestion, we studied mine tailing dust (n = 8), slag dust (n = 5) and smelter dust (n = 4) from old mining and smelting sites in northern Namibia (Kombat, Berg Aukas, Tsumeb). In vitro bioaccessibility testing using extraction in simulated gastric fluid (SGF) was combined with determination of grain-size distributions, chemical and mineralogical characterizations and leaching tests conducted on original dust samples and separated PM₁₀ fractions. The bulk and bioaccessible concentrations of the metal(loid)s were ranked as follows: mine tailing dusts < slag dusts ≪ smelter dusts. Extremely high As and Pb bioaccessibilities in the smelter dusts were caused by the presence of highly soluble phases such as arsenolite (As₂O₃) and various metal-arsenates unstable under the acidic conditions of SGF. The exposure estimates calculated for an adult person of 70 kg at a dust ingestion rate of 50 mg/day indicated that As, Pb (and also Cd to a lesser extent) grossly exceeded tolerable daily intake limits for these contaminants in the case of slag and smelter dusts. The high risk for smelter dusts has been acknowledged, and the safety measures currently adopted by the smelter operator in Tsumeb are necessary to reduce the staff's exposure to contaminated dust. The exposure risk for the local population is only important at the unfenced disposal sites at Berg Aukas, where the PM₁₀ exhibited high levels of bioaccessible Pb.

Adsorptive remediation of cobalt oxide nanoparticles by magnetized α-cellulose fibers from waste paper biomass

Remediation of engineered-nanomaterials is an up-coming major environmental concern. This study demonstrates adsorptive-remediation of cobalt oxide nanoparticles (CoO NPs) from the water. The α-cellulose-fibers were extracted from waste-paper biomass (WP-αCFs) and magnetized with Fe₃O₄ NPs (M-WP-αCFs). The XRD, FT-IR, and TGA were performed for detailed characterization of the newly developed bioadsorbent. The M-WP-αCFs was then applied for adsorptive remediation of CoO NPs. The adsorptive kinetics of CoO NPs adsorption onto the M-WP-αCFs reveals the pseudo-second-order model. The various adsorption isotherm studies revealed Langmuir is a best-fit isotherm. A prominently high adsorption capacity q_m (1567 mg/g) corroborated extraordinary adsorptive potential of M-WP-αCFs. Furthermore, CoO NPs were adsorbed onto M-WP-αCFs were analyzed by the XPS, VSM, and TEM. Therefore, this study gave rise WP biomass extracted and rapidly-separable nano-biocomposite of 'M-WP-αCFs' with a high-capacity for CoO NPs remediation and can be further applied in remediation of several other engineered-nanomaterials.

Preeclampsia and blood lead (and other metals) in Lubumbashi, DR Congo

Among parturient women in Lubumbashi, blood lead concentrations [geometric means (25th-75th percentiles)] were higher among 40 women with preeclampsia [6.66 µg/dL (5.16-79.4)] than among 39 control women matched for age and gestation duration [5.08 µg/dL (4.27-6.30)]. Blood lead exceeded 5 µg/dL in 33 (83%) preeclamptic women and 17 (44%) control women [odds ratio 6.1 (95%CI 2.1-17.1)]. In another study, we found high levels of lead in surface dust collected in front of homes in Lubumbashi (36/127 samples exceeding 120 µg lead/g dust). Our findings support the conclusions of a systematic review that increased blood lead level increases the likelihood of preeclampsia. Moreover, our study indicates that, as in other urban areas in Africa, exposure to lead is unacceptably high among pregnant women in Lubumbashi. Preventive measures are needed to protect mothers and children from the serious adverse effects of lead exposure.

Lead Exposure in Low and Middle-Income Countries: Perspectives and Lessons on Patterns, Injustices, Economics, and Politics

Lead exposure is a legacy issue that continues to affect vulnerable population groups globally, but particularly in low and middle-income countries (LMICS). We take a multi-disciplinary approach to examine the patterns of lead exposure in these countries, discuss the underlying injustices and socio-political causes, and the economic costs that are associated with exposure. We conclude with some lessons we drew from our discussion of lead across the disciplines and advocate for a number of approaches to solving this ongoing issue. These include (i) biomonitoring that could be integrated into existing health surveys or public health programs targeting young children; (ii) greater civic engagement to push for solutions; and, (iii) environmental control policies that represent a continuum of local, context-specific to broad, national-level, and even global approaches.