Human health risk assessment of atmospheric mercury inhalation around three artisanal small-scale gold mining areas in Indonesia

Abstract

To clarify the human health risk of inhalation of gaseous elemental mercury (GEM), we measured GEM concentrations in three artisanal small-scale gold mining (ASGM) areas of Palu (Central Sulawesi, 342 000 residents), Muara Aman (Benkulu in Sumatra, about 1000 residents), and Palangka Raya (Central Kalimantan, 236 000 residents). These sites differed with regard to the scale and method of gold mining (ball mill and dredging systems). Although the scale of ASGM activity at these three sites differed for both the ball mill and dredging methods, gold amalgams were always made during the refining process. The air in these cities was therefore polluted by the mercury used in extracting the gold, although the levels of pollution differed. The highest GEM concentrations were measured at gold shops (5 × 10⁵ ng m⁻³). In the ASGM activity area, the measured GEM concentrations were high (100–14 000 ng m⁻³) near grinding drums. GEM concentrations in Palu and Palangka Raya ranged from 2.06 to 375 ng m⁻³ and 2.04 to 25.3 ng m⁻³, respectively. GEM concentrations within an ASGM community area in Muara Aman ranged from 4.10 to 11.5 ng m⁻³. Our results indicated that the health of residents of Palu—not only in the ASGM area but also in the city—may be at risk due to GEM inhalation. In Muara Aman, the health of people who engage in gold refining and of gold shop employees may be at risk, whereas the health of residents of Palangka Raya appears not to be at risk.