Total mercury and methylmercury levels in eggs from laying hens in a mining area in Bajo Cauca, Antioquia, Colombia

Abstract

Thanks to their unique nutritional components, eggs constitute the source of nourishment for many people. Yet they can also absorb concentrations of several environmental contaminants. This study sought to assess the total mercury (THg) and methylmercury (MeHg) levels in eggs of laying hens from one of the areas with the highest gold mining activity in Colombia. THg and MeHg concentrations were processed in a Direct Mercury Analyzer (DMA) and by gas chromatograph respectively. Risk assessment was conducted based on a dietary survey. The geometric mean Hg concentrations in egg samples were between 3.50 and 10.55 μg g−1 and the highest concentrations of these contaminants were found in the whole egg, followed by the white and the yolk. Mercury showed the highest levels of exposure, which exceeded the safe dose by one unit approximately. Its risk ratio was 2.3. Therefore, daily exposure is likely to cause non-cancer adverse effects during an individual's lifetime. It is critical that this research field continues to investigate risk-mitigation strategies involving the optimization of resources used in mining and agricultural techniques to avoid negative consequences to human health and threats to food security.