Abstract by Natalie Barkdull
Mercury contamination in four Indonesian watersheds affected by small-scale artisanal gold mining
We evaluated mercury (Hg) contamination in four Central Java watersheds affected by artisanal and small-scale gold mining (ASGM). ASGM accounts for almost half of anthropogenic Hg emissions worldwide and causes widespread water pollution. Gold extraction by Hg amalgamation releases Hg-laden sediment and water into local watersheds where anaerobic organisms convert inorganic Hg into toxic organic methylmercury (MeHg). In Indonesia, several studies have identified harmful levels of Hg in fish, sediment, soil, crops, and human hair affected by ASGM; however, to our knowledge no study examines downstream transportation of total Hg and MeHg concentrations. Preliminary results show elevated total Hg concentrations downstream of ASGM sites, with concentrations exceeding 250 ng/L. Adjacent to tailings sites, concentrations exceed 2500 ng/L. This is significant because Indonesians use contaminated river water to irrigate terraced rice fields. This study provides important information to local government agencies in Indonesia seeking to improve water quality in their communities.