Ss08-02 Biomonitoring of Trace Metals in Blood and Urine Among Artisanal Miners in the Democratic Republic of the Congo

Introduction In the Democratic Republic of the Congo, artisanal and small-scale mining employ an estimated 200,000 people, and over a million are indirectly involved through trade and transport. We assessed metal exposure in artisanal miners involved in mining three types of commodities (copper-cobalt, tin, diamonds). Materials and Methods In cross-sectional studies (March 2021 - August 2022), we measured trace metals by Inductive Coupled Plasma Mass Spectrometry (ICP-MS) in blood (µg/L) and urine (µg/g creatinine) in convenience samples of miners (mostly males) extracting copper-cobalt (n=147, four mines, Kolwezi), tin (n=99, three mines around Manono), and diamonds (n=80, Mbuji-Mayi). Results Diamond miners had generally low concentrations (GM with IQR) for most trace metals, except for Pb in blood [74.2 (60.6-90.4)] and urine. Compared to diamond miners, copper-cobalt miners had higher blood concentrations for several elements, especially Co [5.55 (2.87-10.74)], but also Ge, As and Hg; they also had higher urinary concentrations for Co [28.3 (13.5-60.5), Mn, As, Sn, and U [0.031 (0.018-1.265)]. In general, tin miners did not exhibit higher metal concentrations than diamond miners, except for Pb in blood [318 (260-727)] and urine, Tl in blood [0.20 (0.14-0.26)] and urine, as well as As, Sn and U in urine; compared to copper-cobalt miners, tin miners had lower Sn in blood and in urine. Conclusions In this cross-sectional study, we found evidence of substantially higher occupational exposure to cobalt and toxic trace metals in copper-cobalt artisanal miners than in diamond and tin miners. The relatively high concentrations of lead and thallium among tin miners need further research.