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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., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

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., Competing Interests: Competing interests: PMO owns the pharmacy where the study took place., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)