8292625 Biomonitoring of trace metals in blood and urine in workers from a non-ferrous metal smelter: a cross-sectional study in Lubumbashi, DR Congo

<h3>Objective</h3> Little is known about occupational exposure to trace metals during industrial mining and processing in the African Copperbelt. We measured trace metals in blood and urine among workers from a large smelter processing historic slag from the copper industry to produce cobalt, copper, zinc and germanium. <h3>Material and Methods</h3> In a cross-sectional study (July 2023-April 2024), we included, by exhaustive sampling, 292 workers from the smelter (‘smelters’), and for comparison 144 workers from a mineral sampling company (‘samplers’) and 358 brewery workers (‘controls’). Twenty trace elements were measured by ICP-MS in blood and in urine (spot samples) in all participants from the two metal-exposed groups, and in 61 randomly selected controls. Urinary concentrations were corrected by urinary creatinine concentration, with exclusion of highly diluted samples (creatinine &lt;0.3g/L). We compared groups using non-parametric tests. <h3>Results</h3> In blood, median (P25–P75) concentrations (µg/L) were higher for cobalt [0.82 (0.48–1.44)] and lead [190 (102–356)] in smelters than samplers [0.51 (0.29–1.08) and 48.8 (37.0–62.5, respectively] and controls [0.40 (0.29–0.51) and 56.1 (40.6–71.5)], respectively]; blood germanium was significantly higher in smelters [11.8 (11.0–13.0)] than samplers [11.0 (9.7–12.3)], but not different from controls [11.7 (11.0–12.6)]. Urinary concentrations (µg/g creatinine) were higher for cobalt [10.7 (6.64–18.5)], germanium [0.15 (0.04–0.39)] and lead [9.51 (4.08–23.3)] in smelters than samplers [0.83 (0.44–2.29), 0.009 (0.006–0.042) and 1.57 (0.99–2.18), respectively] and controls [0.46 (0.32–0.84), 0.023 (0.014–0.047) and 1.49 (1.15–-2.49), respectively]. <h3>Conclusion</h3> We documented high trace metal concentrations (cobalt, germanium and lead) among workers from a smelting plant. The specific sources of excess exposures should be determined, and policies should be strengthened to protect workers’ health.