Deposition flow of Mercury and Selenium in hair of riverine in habitants of the Amazon, Brazil

Abstract

This paper provides an estimation of Hg, CH3Hg+ and Se levels in hair samples of riverine inhabitants belonging to Itaituba municipality - Barreiras community (area impacted by gold mining underground) and Juruti municipality - Tabatinga community (area without mining impact) (masculine and feminine genus), Pará state (Amazon, Brazil), as well as Hg, CH3Hg+ and Se levels in 12 fish species (carnivores and non-carnivorous), which stand out as the main species consumed by riverside inhabitants, to evaluate a relationship between fish consumption frequency; and Hg, CH3Hg+ and Se concentration, and also to evaluate possible protection mechanisms (or nonprotection) to Hg exposure by Se. Results showed that the levels of Hg, CH3Hg+ and Se found in the present study, which were an average of 15.21 µg g−1 of Hg, 10.48 µg g−1 of CH3Hg+ and 3.64 µg g−1 of Se for male inhabitants and an average of 13.89 µg g−1 of Hg, 10.68µg g−1 of CH3Hg+ and 3.60 µg g−1 of Se for female inhabitants belonging to the Barreira community, were higher than the Hg, CH3Hg+ and Se levels found in hair samples from inhabitants of Tabatinga community and other gold-producing areas, indicating risk for river side populations along the Tapajós river and for Barreira community. From the information of protective effect (or not) of selenium in hair, given the variation in Se concentration and Hg exposition between the two populations, the molar ratio Hg/Se and Hg millimole revealed a plausible correlation averaged for hair samples of riverine inhabitants belonging to Barreiras (R2 = 0.86, p<0.05) and Tabatinga (R2 = 0.57, p<0.05) community. Similarly for the fish, the molar ratio Hg/Se and Hg millimole revealed a plausible correlation averaged for fish samples carnivorous and non-carnivorous (R2 = 0.97, p<0.05).