Banca de QUALIFICAÇÃO: FÁBIO XIMENES DA SILVA

Assessment of human exposure to Methylmercury in riverside of the Lower Madeira River, Porto Velho (Rondônia).

mercury, human contamination, MeHg, human hair, Braszilian Amazon

Methylmercury (MeHg) is an organic derivative of mercury (Hg), a metal available in various chemical forms in nature. The cycle of this element in nature has influences inherent to the environment and also to human actions. This organic variant of mercury spreads throughout the aquatic trophic chain, promoting its accumulation in the tissues of fish, especially piscivores. This fact makes riverside dwellers and indigenous people the most vulnerable populations to methylmercury poisoning, since these communities have a diet rich in fish, which is their main source of protein. In this sense, the objective of this work is to evaluate human exposure of adults to methylmercury through ingestion of fish in four locations in Baixo Madeira, districts of the municipality of Porto Velho-RO (Demarcação, Calama, Nazaré and São Carlos). 701 hair samples were collected in these locations. Participants responded to an individual interview to assess their diet, and hair samples were also collected to investigate prolonged exposure to methylmercury. The work was previously approved by the UNIR Ethics and Research Committee. 366 samples were analyzed for Total Mercury (HgT), including Demarcação (65 samples), Nazaré (137 samples) and 60.7% of the samples collected from Calama (164 samples). The general average of HgT in the community of Demarcação was found to be 7.86 mg.kg^-1, in Nazaré the average was 7.23 mg.kg^-1, and in Calama the preliminary value reached 7.71 mg.kg^-1. It is noteworthy that these values are above the limit considered a guideline value of 7.00 mg.kg^-1 as established by the World Health Organization.