Air Mercury Contamination in the Gold Mining Town of Portovelo, Ecuador

Portovelo is one of the oldest gold mining towns in Ecuador. Artisanal gold mining still uses mercury in the process of gold recovery. In this study, mercury concentrations in the air of Portovelo were evaluated. High mercury levels in the ambient were found in El Pache sector, where most gold mining processing plants are located. These varied between 2,356.7 ± 1,807.6 and 3,699.5 ± 1,225.3 ng/m3 during the rainy and dry seasons, respectively. Lower levels were detected in the urban (central) area of Portovelo, with 214.6 ± 43.7 ng/m3 in the rainy season and 574.2 ± 72.8 ng/m3 in the dry season, exceeding the Agency for Toxic Substances and Disease Registry minimum risk level of 200 ng/m3. Average mercury concentrations in exhaled air from miners, measured before and after amalgam burning ranged between 179–1,352 and 2,007–3,389 ng/m3, respectively. These data suggest Portovelo air is polluted with mercury and humans are being dangerously exposed. Therefore, strong actions must be undertaken to protect human and environmental health, including changing gold recovery systems.