Mercury exposure among artisanal gold miners in Madre de Dios, Peru: a cross-sectional study

Exposure to mercury, a toxic metal, occurs primarily from inhaling mercury vapors or consuming methylmercury-contaminated fish. One third of all anthropogenic mercury emissions worldwide are from artisanal gold mining, which uses mercury to extract gold. Although recent reports suggest that the Madre de Dios region in Peru (with >30,000 artisanal miners) has extensive mercury contamination, residents had never been assessed for mercury exposure. Thus, our objective was to quantify mercury exposure among residents of an artisanal mining town in Madre de Dios and to assess risk factors for exposure.

We conducted a cross-sectional assessment of 103 residents of an artisanal gold mining town in July 2010. Each participant provided a urine and blood sample and completed a questionnaire assessing potential exposures and health outcomes. We calculated geometric mean (GM) urine total mercury and blood methylmercury concentrations and compared log-transformed concentrations between subgroups using linear regression.

One third (34.0 %) of participants were gold miners. All participants had detectable urine total mercury (GM, 5.5 μg/g creatinine; range, 0.7-151 μg/g creatinine) and 91 % had detectable blood methylmercury (GM, 2.7 μg/L; range, 0.6-10 μg/L); 13 participants (13 %) reported having kidney dysfunction or a neurological disorder. Urine total mercury concentrations were higher among people who heated gold-mercury amalgams compared with people who never heated amalgams (p < 0.05); methylmercury concentrations were higher among fish consumers compared with nonfish consumers (p < 0.05).

Our findings suggest that mercury exposure may be widespread in Huaypetue.