Co-Exposure to Lead and Mercury among Artisanal Gold Miners

Abstract

Background: Illegal mining pitch and metal ores processing sites are frequently seen in many parts of Nigerian communities. Gold ore processing is widespread in communities of Zamfara State. These activities produce significant amount of dust that pollute the environment. Aim: The study was conducted to determine the extent of exposure to lead and mercury in artisanal gold miners in Bagega and Kawaye districts and Yargalma village of Anka and Bukkuyum Local Government Areas respectively. Methods:  Seventy gold ore miners were recruited from twelve different mining or processing sites of the affected villages. Serum lead determination was carried out using Atomic Absorption Spectrophotometer (AAS Perkin Elmer, 6300 model USA) and mercury was determined by cold vapor atomic absorption spectrometry (Spectra-10 varian). Results: The blood lead and mercury levels of the exposed individuals ranged between 15 – 561.2 µg/dl and 0.21 – 196 µg/dl respectively. Majority (75.7%) had blood lead levels beyond 45 µg/dl with average mean of 368.62±15.20 and mean blood mercury levels of 168.86±8.92 µg/dl. The blood lead and mercury levels were significantly (p<0.05) high in 16-30 age bracket compared to 0-15 and 31-45 age groups. Similarly, Individuals from Bagega village had significantly (p<0.05) high blood lead and mercury levels compared to Kawaye and Yargalma villages. The high blood lead and mercury levels recorded in this study are far above OSHA permissible limit (40 µ/dl) and are therefore a call for concern. Conclusion: The results indicate the co-exposure to lead and mercury in the artisanal gold miners. The individuals in age bracket 16-30 years are at high risk of synergistic adverse health effects of lead and mercury toxicities. The exposed individuals require urgent medical attention for proper intervention and possible total withdrawal from the work.