TAPPIZ, B.SILVA, P.S.C.OSTERMANN, C.K.LIMA, N.P.BRAGUIN, L.N.M.BOTIA, S.LEVIN, I.BUSTILLOS, O.V.2024-02-022024-02-02TAPPIZ, B.; SILVA, P.S.C.; OSTERMANN, C.K.; LIMA, N.P.; BRAGUIN, L.N.M.; BOTIA, S.; LEVIN, I.; BUSTILLOS, O.V. Assessment of 238U and 226Ra activity concentration along the Amazon Tall Tower Observatory site. In: INTERNATIONAL CONFERENCE ON ENVIRONMENTAL RADIOACTIVITY, 7th, September 17-22, 2023, Seville, Spain. <b>Abstract...</b> Seville, Spain: Universidad de Sevilla, 2023. p. 51-51. Disponível em: http://repositorio.ipen.br/handle/123456789/34457.http://repositorio.ipen.br/handle/123456789/34457The Amazon Tall Tower Observatory (ATTO) site is a region located within the Uatumã Sustainable Development Reserve (USRD), approximately 150 km northeast of Manaus city, in the Brazilian state of Amazonas. At the ATTO site, there are 3 tall towers, which are used for studies on the Amazon rainforest and its interaction with the soil and the atmosphere. The activity concentration of 238U and 226Ra was determined in soil samples collected in the footprint of the ATTO site by gamma spectrometry. The activity concentration of these radionuclides is important for understanding the 222Rn exhalation rate and 222Rn flux from soils. Knowledge of the 222Rn flux at the ATTO site can be useful for applications in atmospheric research, e.g., the 222Rn tracer method can be used to estimate local and regional emissions of greenhouse gasses; simulating 222Rn transport is a powerful tool for evaluation and validation of transport schemes in atmospheric chemical transport models. In this study, 39 samples collected from 13 sampling sites along a transect from the ATTO site to the river were analyzed. The highest activity concentrations were found in the Igapó forest (69 ± 2 Bq/kg for 238U and 47 ± 5 Bq/kg for 226Ra), a region near the Uatumã river with prevailing flooded black-water forest, whereas the lowest activity concentrations occurred in the Campina (Savanna on white-sand soils) and Campinanara (white-sand forest) ecosystems (18 ± 1 Bq/kg for 238U and 13 ± 2 Bq/kg for 226Ra), a transition area located between river terraces and the Terra Firme forest.51-51openAccessResumo de eventos científicoshttps://orcid.org/0000-0002-4712-4057https://orcid.org/0000-0002-9351-9201