Monitoring Hg emissions from gold shops in Peru: Science vs policy

Author

Adam M. Kiefer, Chemistry Dept., Mercer University, Macon, GA
kiefer_am@mercer.edu

Monica Silva González, Ministerio del Ambiente, Lima, Peru
Caryn S. Seney, Mercer University
Keegan H. Moody, Mercer University
Kazi Hasan, Mercer University
Victoria Blakeman, Mercer University
Lillian Hicks, Mercer University
Danielle Loving, Mercer University
Sumeja Aljic, Mercer University
Craig McMahan, Mercer University
Matthew E. Moore, Mercer University

Presentation

257th ACS National Meeting - Orlando
Monday, April 1, 2019, 10:00am-10:45am
Orange County Convention Center Room W308D
"Monitoring Hg emissions from gold shops in Peru: Science vs policy”

Abstract

Artisanal and Small-scale Gold Mining (ASGM) activities in Madre de Dios, Peru have resulted in widespread deforestation and environmental contamination with mercury. Amalgamation of gold ore concentrated on sluice boxes and the subsequent heating of the amalgam to isolate sponge gold releases large quantities of Hg° into the atmosphere. This problem is compounded by the fact that gold buyers in the region are often located in populated residential areas, burn the amalgams and reheat the sponge gold, releasing mercury vapor directly into the air at street level. For compliance with the Minamata Convention, monitoring and estimation of Hg emissions is essential. Peru requested the assistance of Mercer University to perform a preliminary assessment to quantify Hg emissions in ASGM areas. As a result, a study was organized to preliminarily quantify Hg emissions from gold shops. During October of 2017 and May of 2018, the location of gold shops and point sources of Hg° contamination throughout the city of Laberinto were mapped using a Lumex RA-915M AAS coupled with a GPS unit. The Peruvian standard norm establishes that total gaseous mercury (TGM) concentrations do not exceed an average of 2,000 ng/m3 over 24 hours. However, concentrations of Hg° in and around these gold shops often exceeded 2,000,000 ng/m3. While these concentrations far exceed the national air quality standard for total gaseous mercury (TGM) in Peru, the spectrometer used to measure these concentrations only monitors Hg° - one component of TGM. Because the standard norm requires TGM measurements, the data collected cannot be used for assessment purposes. The findings of the present study demonstrate 1) the need for a more specific environmental assessment of ASGM communities based on Hg° vapor as opposed to TGM and 2) the need for development of a correction factor for Hg° measurements to estimate TGM. Currently, protocols are being developed to define guidelines for monitoring airborne Hg concentrations throughout Peru including ASGM areas.