Toxicologie environnementale et analytique

Quantification of Metal in the Hair of Copper Miners in Katanga Province, Democratic Republic of Congo

Abstract

Myriam Molayi Elenge, Jean-Claude Aubry, Luc Jacob and Christophe De Brouwer

This study aims to demonstrate the exposure of artisanal miners to the contents of mineralised gangue and to assess whether the different workstations and their related operating processes potentiate such exposure. The population sampled (n=100) consisted of artisanal miners operating in the mine of Ruashi, in the south of the Katanga copper belt. We made use of hair as a biomarker and performed our analyses using ICP-MS. According to recommendations from the Agency for Toxic Substances and Disease Registry, we have compared our results to those of an unexposed population living in the same area in order to point out the occupational origins of such exposure. In our hair analysis, we identified and quantified 22 elements. For almost all of these elements, the artisanal miners had much higher values as compared to the control population. In addition, non-diggers had higher levels than diggers for almost all of the elements that could be directly linked to those present in the mineralised gangue. Median values obtained for the artisanal miners were systematically higher than those of the control population, reflecting a higher than normal exposure. Such differences between the two sample populations can only be explained by the occupational (mining) origin of exposure, since the living environment, hair nature, sampling method, and analysis techniques were the same for both populations. Medians within the miner samples showed different exposure profiles for non-diggers versus diggers, resulting from the fact that non-diggers were more exposed to the mineralised gangue. The results attest to the reality and the large extent to which artisanal miners in Katanga Province are exposed to chemical components of mineralised gangue. This exposure is more significant within the workstations related to the raw mineral processing phase as opposed to the extraction phase.