Mercury emissions from Peruvian gold shops: Potential ramifications for Minamata compliance in artisanal and small-scale gold mining communities

Ratification of the Minamata Convention on Mercury has led to the establishment of Peruvian regulations limiting mercury concentrations in air to 2000 ng/m(3) over a 24-hr measurement period. As a result, three communities in Madre de Dios, Peru were mapped during October 2017 to determine Hg-0 vapor concentrations in the air. The town of Tres Islas exhibited Hg-0 concentrations less than 200 ng/m(3): the minimum risk level defined by the Agency for Toxic Substances and Disease Registry. These low concentrations were reflective of a town in the region with limited exposure to artisanal and small-scale gold mining (ASGM). However, the ASGM communities of Laberinto and Delta One exhibited concentrations of Hg-0 vapor that exceeded 2,000,000 ng/m(3) surrounding active gold shops, where amalgams and processed amalgams were heated with open flames. Laberinto was reevaluated in May 2018 during which time Hg-0 levels on the sidewalks in front of gold shops again exceeded 2,000,000 ng/m(3). Within the scope of this paper a rapid mapping technique allows for the detection of sources of Hg-0 pollution and identifies neighborhoods that require intervention to decrease Hg-0 emissions. In addition, this work highlights the difficulties of measuring total gaseous mercury in ASGM communities with gold shops according to the Peruvian law.