Banca de QUALIFICAÇÃO: IURI APARECIDA DA SILVA OLIVEIRA

POTENTIAL BIOMAGNIFICATION OF METHYLMERCURY IN THE PLANKTONIC COMMUNITY OF ALTO RIO MADEIRA (RO)

Keywords: Contamination; Mercury; Methyl mercury; aquatic ecosystem.

Mercury (Hg) participated in numerous chemical reactions in our aquatic ecosystems, possibly transforming itself from this inorganic chemical form into an organic one and quickly incorporated into the biota. In these cases, monitoring is necessary, for intervention actions in cases of environmental imbalances, which may occur due to the presence of this element in the fixed ecosystems. Data from the laboratory database from data 2009 to 2019 will be used. Data from the laboratory database will be used. of Environmental Biogeochemistry WCP/UNIR. The samples were collected in nylon nets, stored, refrigerated and transported to the laboratory, to later be prepared for quantification of mercury levels. The results obtained in general showed that the average total Hg concentrations (THg), seasonally and over time, did not show great variations between the studied tributaries, seasonality affected the average concentrations of each tributary differently, the Jatuarana II stream presented the highest concentrations averages over time. The average concentrations of MeHg in general were lower in the Jaci Paraná River and higher in the Jatuarana II stream, zooplankton (160µm) stood out with the highest average concentrations in all seasonal periods and over time the average concentrations increased after rearing. of the reservoir (2011). The results obtained in this study are similar to the results of other studies carried out in the Amazon region and in the Madeira River basin, and demonstrate that the biomagnification of MeHg occurs in the studied planktonic community, the increase in MeHg concentrations downstream of the hydroelectric reservoir can be a indication that the methylmercury produced in the reservoir is being exported.