Mercury emissions from Peruvian gold shops: Potential ramifications for Minamata compliance in artisanal and...

Ratification of the Minamata Convention on Mercury has led to the establishment of Peruvian regulations limiting mercury concentrations in air to 2000 ng/m³over a 24-hr measurement period. As a result, three communities in Madre de Dios, Peru were mapped during October 2017 to determine Hg⁰ vapor concentrations in the air. The town of Tres Islas exhibited Hg⁰ concentrations less than 200 ng/m³: 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 Hg⁰ vapor that exceeded 2,000,000 ng/m³ surrounding active gold shops, where amalgams and processed amalgams were heated with open flames. Laberinto was reevaluated in May 2018 during which time Hg⁰ levels on the sidewalks in front of gold shops again exceeded 2,000,000 ng/m³. Within the scope of this paper a rapid mapping technique allows for the detection of sources of Hg⁰ pollution and identifies neighborhoods that require intervention to decrease Hg⁰ emissions. In addition, this work highlights the difficulties of measuring total gaseous mercury in ASGM communities with gold shops according to the Peruvian law.