Mercury exposures in riverside Amazon communities in Pará, Brazil

Cross-sectional studies were conducted in three riverside communities in the state of Pará in the Amazon Region of Brazil. Two of these communities, Brasília Legal and São Luís do Tapajós, are located in a watershed exposed to mercury pollution from artisanal gold mining, and the third, Santana do Ituqui, is outside this area. The studies were based upon a community census and included all persons volunteering for participation in each community. All participants were surveyed by questionnaire for health history, occupation, residence, and diet. Clinical evaluations were also done on each subject, along with collection of blood, urine, feces, and hair. Fish samples were collected to represent the most frequently consumed species. Mercury was measured in hair and fish. Although no signs or symptoms of overt mercury intoxication were observed, persons in Brasília Legal and São Luís do Tapajós had higher levels of mercury in hair than residents of Santana de Ituqui, located out of the risk area. Levels of mercury in fish were below Brazilian health guidance limits, but the high rates of fish consumption among these populations raise concerns for the possible effects of chronic exposure, especially among young children and women of childbearing age.