Guest Speaker: Dr. Sarah Diringer on mercury contamination in rainforests of Peru

A recent report from The Guardian suggests a "chronic mercury epidemic" in Peru. Dr. Sarah Diringer visits SFEI to share her new findings on the impacts of gold mining and deforestation on mercury mobilization in the Peruvian rainforest. Join us!

Title: Artisanal and small-scale gold mining (ASGM) exacerbates soil and heavy metal mobilization in Peru

Description: Artisanal and small-scale gold mining (ASGM) is the largest anthropogenic source of mercury (Hg) to the atmosphere worldwide and a significant contributor to deforestation. In Madre de Dios Peru, mining and deforestation have increased dramatically since the 1980s. Field sampling in Feb 2015 identified a strong correlation between Hg and suspended solids concentrations, with especially high suspended solids concentrations downstream of ASGM activity. This supports the hypothesis that Hg transport in this region is facilitated by soil mobilization and runoff. In order to understand how ASGM activity in the Puquiri affects sediment mobilization from the watershed over time, we employed a watershed-scale soil mobilization model in ArcGIS using satellite imagery from 1986 to 2014. The model estimated that soil mobilization in the Colorado River watershed increased by 2.5 times during the time period, and increased by 6 times in the heavily mined subwatershed, leading to between 10 and 60 kg of Hg mobilized in 2014. If deforestation continues at its current exponential rate through 2030, soil and heavy metal mobilization may increase by five times. This research shows that deforestation associated with ASGM in Madre de Dios can exacerbate soil mobilization and Hg contamination downstream.