Mercury Levels of Environmentally and Occupationally Exposed Residents in Bornuur and Jargalant Districts of Mongolia

Introduction: Bornuur and Jargalant districts are sites with relatively long history of artisanal gold mining. The findings of this study are presented in the context of previous mercury exposure assessment conducted in 2008 by the WHO. This article summarizes the assessment of environmental and occupational exposure to mercury in the region following recent implementation of National Mercury Risk Management policies. Methods: A total of 79 blood and urine samples were analyzed for mercury content and grouped as: (1) as occupational exposure for high and medium values and (2) as an environmental exposure for low values. Mongolian background values for mercury content in blood and urine were used as a control. Internal mercury content distributions of the subgroups were compared using statistical tests. Results: The study revealed substantial reduction of mercury urine levels for both occupational (from 5.7µl/L in 2008 to 2.5µl/L in 2012) and environmental (4.78µl/L in 2008 to 1.09µl/L in 2012) exposure, opposite to the increase its level in blood (from 0.55µl/L in 2008 to 0.7µl/L in 2012 for occupational and from 0.33µl/L in 2008 to 0.48µl/L in 2012 for environmental exposure). Conclusion: Lowered urine levels of mercury indicate tendency for gradual decrease of exposure to it in study area, despite recent to the time of study exposure. Mining is remaining to be main exposure source for mercury in Mongolia; therefore the issue of mercury pollution could be regulated and prevented by proper policy measurements from the government towards artisanal mining.