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 28500 Trace and major elements, natural and artificial radionuclides assessment in bottom sediments from Tietê River basin, São Paulo State, Brazil2022 - MAZZILLI, BARBARA P.; LAVIERI, LETICIA G.S.; SOARES, JOSIANE S.; ROCHA, FLAVIO R.; ANGELINI, MATHEUS; FAVARO, DEBORAH I.T.This paper aims at quantifying natural and artificial radionuclides, trace and major elements in sediments collected along the Tietê River basin. The results obtained for Cd, Cr, Cu, Ni and Zn, indicated that the region of “High Tietê” is highly polluted, followed by the region of “Middle Tietê” and the region of “Low Tietê” does not present evidence of contamination. The natural radionuclide concentrations were of the same order of magnitude of world average values and can be defined as basal levels of the region. Cesium-137 activity concentration ranged from 0.22 ± 0.08 Bq kg−1 to 0.96 ± 0.12 Bq kg−1.