Diffusion of mercury from artisanal small-scale gold mining (ASGM) sites in Myanmar

Abstract

In some developing countries, such as Myanmar, mercury used for gold refining in artisanal small-scale gold mining (ASGM) is emitted into the atmosphere and water, causing environmental pollution. In this study, the diffusion of mercury from ASGM in Thabeikkyin Township, Mandalay Division, Myanmar was investigated. Air samples, water samples and hair were collected from the ASGM sites. The mercury concentration in the atmosphere in the gold mining area reached 74,000 ng/m3 at the maximum concentration, which exceeded the WHO guideline of 1,000 ng/m3. The mercury concentration in the Ayeyarwady River and the groundwater pumped from the gold mining tunnel was 4.6 ng/l and 29-35 ng/l, respectively. The limit of mercury in hair is considered to be 50 μg/g, at which concentration nervous symptoms may appear, while 11 μg/g is the concentration at which adverse effects on fetuses could take place. The average mercury concentration in hair was 1.5 μg/g for ASGM workers, while it was 1.1 μg/g for nonworkers. An analysis of hair indicated that the mercury was not at a level that would adversely affect human health, so far.