Metals in water used by artisanal and small-scale gold miners for gold-mercury amalgamation in Western Kenya

Concentrations of arsenic, chromium, manganese and lead to which ASGM workers are exposed in the amalgamation process were approximately 5-100-fold higher concentrations than reported in prior studies of metals in surface waters near ASGM sites. These findings should be useful in assessments of exposure and health risk of the many thousands ASGM workers who amalgamate milled ore. The high concentrations of As, Mn and Hg put at risk the health of children who live near or work at ASGM sites. Policy measures and changes in occupational practices are urgently needed to reduce Hg use in ASGM and to protect individuals from metals present in milled ore.