RESUMEN
Gold mining in the savannah region of northern Brazil (Roraima) has increased dramatically since 1989. Elemental mercury is used to extract gold from sediment. Mercury released into the Amazon aquatic ecosystem may convert into the organic form and bioconcentrate in the food chain, posing a hazard for fish-eating peoples such as some of the Makuxi. This survey compared blood organic mercury levels among Makuxi villagers along mined (Rio Cotingo) and unmined (Rio Surumu) rivers. Seventy-five blood samples were obtained from villagers who did not participate in gold mining or processing procedures in three Makuxi villages: Maravilha (heavily exposed), Limão (limitedly exposed), and Matarucca (minimally exposed). Blood was analyzed for total and inorganic mercury content by cold vapor spectrophotometry. Mean blood organic mercury levels among the villagers of Maravilha, Limão, and Matarucca were 31.3 mg/L, 9.3 mg/L, and 2.0 mg/L, respectively (p = 0.001). The authors conclude the gold mining process is contaminating the environment of Roraima and may pose a health hazard to its fish-eating populations, such as the Makuxi people.
