ICMGP - Conference Presentation

Abstract Information :

A compilation of data on total mercury levels (HgT) in muscle tissue of fish collected in the Brazilian Amazon was carried out, with bibliographic review and primary data generated in CETEM/LEMA in the last 20 years (1999 to 2019). Fish were collected in different watersheds (Tapaj¢s River, Madeira River, and others) of different sub-basin levels (IV, III, II) and in areas affected by small-scale gold mining, deforestation/agriculture, and in reference areas. The inventory of available information on the popular name of the fish, their scientific names, mercury levels and eating habits of each species, as well as the date of collection, was organized in spreadsheets. The primary data generated in LEMA make up about 50% of the total of 2,250 results analyzed here. The weighted averages of mercury for this sample resulted in 282.94æg/kg (n=2,250). The mercury levels in carnivorous fish resulted in 518.99æg/kg and in non-carnivorous fish resulted in 196.34æg/kg, expressing the recognized biomagnification of methylmercury in the aquatic trophic chain. The species with carnivorous feeding habits that presented the highest levels of mercury are tra¡ra (945.3æg/kg; n=207) and tucunar‚ (517.98æg/kg; n=148). The levels of HgT in fish observed from this compilation certainly do not represent the reality of such huge territory, more than 5 million km2, but rather, they allow obtaining a dimension, in terms of order of magnitude, of these levels. We emphasize the importance of integrating all the data generated by several studies already carried out on Hg in fish from the Brazilian Amazon. This task can be facilitated by creating a database fed by all researchers. From the critical analysis of the uncertainties associated with the HgT data in Amazonian fish, we will present as a suggestion for the standardization of the database, the insertion of minimum parameters and others, desirable.