Total and inorganic Hg in 55 samples of hair from riverines, mainly descended from Munduruku and Apiaka Indians, living along the rivers Teles Pires and Juruena have been determined. The sampled population represents 18% of the inhabitants of the region and they eat fish 6 or 7 days a week. Cold-vapor AAS and alkaline digestion with CdCl2/SnCl2 as reducing agent were employed to estimate total Hg in hair samples. A LDC Analytical, Mod. 1255, Mercury monitor was used for Hg determination. The mean value of total Hg was 34.2 mu g g(-1), with an average of 87.2% of organic Hg. Ninety-three per cent of the sampled population present levels of Hg above 10 mu g g(-1), and 18% over 50 mu g g(-1). A relationship between the mean value of Hg and age of the sampled population is presented. All women at child-bearing age present concentrations of Hg above 10 mu g g(-1). Fifty-four per cent of them had levels over 30 mu g, with a mean of 41.2 mu g g(-1). For the children under ten years of age, 14% show Hg concentration above 50 mu g g(-1). Comparison of these results with those obtained in 10 other Amazon surveys (n=1672) is shown. The results of the concentration of mercury in fish, mainly piscivorous (n=967) from Amazonian and Wetland (pantanal matogrossense) are also presented, with a mean of 726 ng mg(-1). There appears to be a relationship between level of Hg in human and their food ingestion habits.
