FLAVIO ROBERTO ROCHA
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Artigo IPEN-doc 30344 Oyster shell element composition as a proxy for environmental studies2024 - SILVA, PAULO S.C. da; FARIAS, WELLINGTON de M.; GOMEZ, MAURO R.B.P.; TORRECILHA, JEFFERSON K.; ROCHA, FLAVIO R.; SCAPIN, MARCOS A.; GARCIA, RAFAEL H.L.; SIMONE, LUIS R.L. de; AMARAL, VANESSA S. de; VINCENT, MOUCHI; LAURENT, EMMANUEL; RUDNICKI-VELASQUEZ, PAWELThe use of mollusks' shell as a proxy for long-term trend prediction in the variability of coastal zones has been used as an attempt to understand the consequences that environmental changes may cause to the functioning of coastal ecosystems. This study exploited the elemental concentration, elemental ratios and mineralogy of oyster shells of the genus Crassostrea to infer spatial variations in the environment of the animal's growth. Modern oyster shell samples of the Crassostrea brasiliana and Crassostrea mangle species were analyzed by neutron activation analysis, X-ray diffraction, X-ray fluorescence and Graphite Furnace Atomic Absorption Spectrometry. Data normalization by the enrichment factor relative to lanthanum (La), considered as a conservative element in seawater, and statistical multivariate analyses indicate that the elemental composition and trace element ratios differ when comparing oyster shells from different regions. The results showed that the performed analyses may be useful for the characterization of the environment in which oysters grow.Artigo IPEN-doc 25799 Natural and artificial nuclides in Salesópolis reservoir2019 - SILVA, P.S.C.; SEMMLER, R.; ZAHN, G.S.; ROCHA, F.R.; DAMATTO, S.R.; FAVARO, D.I.T.Natural radioactivity is ubiquitous in the environment mainly due to the presence of the nuclides from the ura-nium and thorium series and 40K. Although in the South Hemisphere nuclear tests have been fewer in number than that in the North, artificial radionuclides can also be found spread at ground level. In this study, the activity concentrations of natural nuclides from the uranium and thorium series, 40K and the artificial 137Cs were deter-mined in a sediment core with 42 cm depth collected in the middle of the Salesópolis reservoir, located in the Metropolitan Region of São Paulo city (SPMR). The Usina Parque Rio Tietê reservoir belongs to the Alto do Tietê system for the capture, storage and treatment of water for SPMR. Therefore, the quality of the water and sediments of this dam is of great importance. The activity concentrations were measured by gamma spectrome-try. Samples were measured and saved at regular intervals at a maximum of 160 000 seconds. The gross area were determined for each peak and plotted against time and the counting rate was obtained by the slope of the curve. Background and reference materials were also counted and treated in the same way. Results showed that 226Ra varied from 45 to 116 Bq kg-1; 228Ra, from 80 to 165 Bq kg-1; 40K, from 155 to 1 187 Bq kg-1 and 137Cs varied from 0.3 to 7 Bq kg-1. The methodology applied for determining low levels of 137Cs in sediment proved to be effi-cient and reproducible.Resumo IPEN-doc 25012 Metal and trace element assessment in bottom sediments from medium Tietê River Basin, by INAA and ICP OES techniques2017 - ROCHA, FLAVIO R.; ANGELINI, MATHEUS; HENRIQUES, HELOISE R.; SOARES, JOSIANE S.; SILVA, PAULO S.C.; FAVARO, DEBORAH I.T.Artigo IPEN-doc 24078 Natural and artificial nuclides in Salesópolis reservoir by gamma spectrometry2017 - SILVA, PAULO S.C.; SEMMLER, RENATO; ZAHN, GUILHERME S.; ROCHA, FLAVIO R.; DAMATTO, SANDRA R.; FAVARO, DEBORAH I.T.Resumo IPEN-doc 21548 Trace elements by neutron activation analysis in three sediments cores from the Alto Tietê River sub-basin, São Paulo-Brazil, dated by 210Pb method2015 - FAVARO, DEBORAH; ROCHA, FLAVIO; DAMATTO, SANDRA R.; WAKASUGI, DENISE; SILVA, PAULO S.