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Characterization of Mercury Emissions from ASGM Goldshop Activities in Peru
Citation:
Ryan, J., M. Livingood, AND S. Durkee. Characterization of Mercury Emissions from ASGM Goldshop Activities in Peru. Intl Conf on Mercury as a Global Pollutant, Edinburg, SCOTLAND, July 28 - August 04, 2013.
Impact/Purpose:
The US Environmental Protection Agency (EPA), a member of the UNEP Global Mercury Partnership, assembled a team of researchers to travel to two geographically-distinct regions in Peru to empirically characterize the Hg emissions from amalgam burning in ASGM shops. Specifically, this study was intended to make the first known speciated emissions measurements for RGM, while also improving the knowledge of overall Hg emissions, thereby providing information for further impact analyses. The study also afforded the opportunity to better understand the inhalation exposures to workers in these ASGM shops.
Description:
Mercury (Hg), used in artisanal small-scale gold mining (ASGM) practices, is recognized as a significant source of Hg release to the environment and is a major area of focus of the United Nations Environment Programme (UNEP) Global Mercury Partnership. Hg is used to bind (form an amalgam with) gold, where the Hg present is subsequently burned off from the amalgam to recover the remaining gold while releasing the volatilized Hg. This process is performed in the field as well as in the central “shops”, where the gold is ultimately purchased. Little is understood of the forms and distribution of Hg species emitted from the amalgam burning practice and the resulting local, regional, and global implications associated with the Hg releases. The oxidized form of Hg, also known as divalent or reactive gaseous mercury (RGM), is of particular interest because it is water soluble and can deposit locally. Moreover, it is this water soluble form that provides the route to methylation and subsequent bioaccumulation. The ASGM Hg amalgam burning practices also often result in significant inhalation exposure to those involved, especially in the confined shop environments. The US Environmental Protection Agency (EPA), a member of the UNEP Global Mercury Partnership, assembled a team of researchers to travel to two geographically-distinct regions in Peru to empirically characterize the Hg emissions from amalgam burning in ASGM shops. Specifically, this study was intended to make the first known speciated emissions measurements for RGM, while also improving the knowledge of overall Hg emissions, thereby providing information for further impact analyses. The study also afforded the opportunity to better understand the inhalation exposures to workers in these ASGM shops. Using EPA-developed measurement approaches, the EPA research team characterized the Hg emissions from ASGM gold shops in Puerto Maldonado ( a town in the Madre De Dios Amazonian Region) and La Rinconada (a town in the high elevation Andes Region). Various Hg speciating measurement samples were collected while gold-containing Hg amalgam was burned in ASGM shop “hoods” of various configurations, including several equipped with EPA’s Mercury Control System (MCS). Ambient and personal exposure measurements were made with conventional badge samplers. Ancillary data were collected to aid in characterizing overall emissions.This presentation will describe the measurement methodologies used, the results of emissions characterizations at the two locations, and results of personal exposure assessments. In addition, the emission characterizations will be used to estimate overall speciated mass emissions, including mass balances, for the high altitude region.