ANDRE RODRIGO DA SILVA

ANDRE RODRIGO DA SILVA

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Radionuclides of natural origin in environmental samples collected in the catchment area of Ponte Nova reservoir, São Paulo, Brazil
2018 - SILVA, A.R.; DAMATTO, S.R.; LEONARDO, L.; GONÇALVES, P.N.; SOUZA, J.M.; MADUAR, M.F.
Natural radiation is generally classified as terrestrial primordial radiation or cosmogenic radiation. Primordial radiation is mostly due to the decay series of 238U and 232Th and is present in soil, sediments and water; another important source of natural radiation is 40K. Reservoirs are a very dynamic system with several phenomena to study, due to their huge impact on ecosystems and river flow. Ponte Nova reservoir (23°34'43.23"S, 45°56'56.76"W) is the first reservoir in a cascade system that was built in the 1970s to control the Upper Tietê River basin water flow. In the present work, the activity concentrations of 238U, 226Ra, 210Pb, 232Th, 228Th, 228Ra and 40K were determined using instrumental neutron activation analysis and gamma spectrometry in soil profiles collected in the catchment area of Ponte Nova Reservoir and sediment cores collected close to the soil samples. The highest concentration obtained in the soil samples was for 40K that varied from 49 to 2410 Bq/kg and 210Pb in the sediment samples, which varied from 20 to 774 Bq/kg. Cluster analysis and principal component analysis were applied to all the results obtained to verify a probable correlation between the radionuclides determined in the soil and sediment samples.
Major, minor and trace elements determination using INAA in soil profile and sediment core samples collected in the catchment area of ponte nova reservoir, São Paulo – Brazil
2017 - SILVA, A.R.; DAMATTO, S.R.; LEONARDO, L.; SOUZA, J.M. de; GONÇALVES, P.N.; MADUAR, M.F.
Elemental Chemical Characterization is a keystone in understanding environmental phenomena and its effects. Major and trace elements give important data about geological, physical, chemical and biological phenomena undergoing in natural environments. Ponte Nova reservoir (23 34’43.23" S, 45 56’56.76" W) is the first reservoir in a cascade system that was built in the 1970s to control Upper Tietê River basin water flow. Nowadays, this reservoir serves as a source of water for agricultural and industrial enterprises and as drinkable water source, and were a major concern for the population of São Paulo state due to a recent severe drought in the years of 2014 and 2015. In the present work, major and trace elements (As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Tb, Yb and Zn) were determined using Instrumental Neutron Activation Analysis (INAA) in the IEA-R1 nuclear reactor using the comparative method. This procedure consists in exposing 200mg of the sample and reference materials sealed in polypropylene bags to a thermal neutron flux of 1 1012 cm􀀀2s􀀀1. Geo-accumulation indexes and enrichment factors were determined and physicochemical parameters (grain size analysis, pH, real and apparent densities, Loss on Ignition, porosity and humidity) were measured. The major and trace element concentrations were compared with the Upper Continental Crust values. Cluster analysis, correlation matrix and principal component analysis were applied in all the results obtained to verify a probable correlation between the major and trace elements determined in the soil and sediment samples.
Natural radionuclides from U-238 and TH-232 series and inorganic chemical characterization of soil profiles and sediment cores of the Taiaçupeba Reservoir, São Paulo, Brazil
2017 - SOUZA, J.M.; DAMATTO, S.R.; LEONARDO, L.; SURKOV, A.M.; SILVA, A.R.; MADUAR, M.F.; GONÇALVES, P.N.
Taiaçupeba reservoir, located in the state of São Paulo, Brazil, belongs to Producer System of Alto Tietê (Sistema Produtor Alto Tietê) and it is responsible for water supply for about 3.1million of people. The water quality of a reservoir is very important, but this is reduced by the increase of environmental degradation of the soil around the reservoir and its different uses. The study of soil profiles and sediment cores is an important tool for understanding the geophysical and geochemical aspects of an aquatic ecosystem. The objective of this work was to present the natural radionuclides 238U, 226Ra, 210Pb, 232Th, 228Th, 228Ra and 40K activity concentrations and also the inorganic chemical characterization of four soil profiles and four sediment cores collected in the area of influence area of Taiaçupeba reservoir. The analytical techniques, gamma spectrometry and instrumental neutron activation analysis were used in the determination. In the soil profiles the highest activity concentrations were obtained for the radionuclides 40K and 228Th and the lowest for 210Pb; in the sediment cores the highest activity concentrations were obtained for the radionuclide 210Pb and the lowest for 226Ra and 228Ra. For the inorganic chemical characterization the highest values obtained were for Na, As and Sb; in a sediment core a very high concentration was obtained for the element Zn indicating a probable accumulation of this element inside the reservoir; enrichment factor was used to evaluate a possible anthropic contamination in the soil and sediment at the margins of Taiacupeba reservoir.
Assessment of natural radionuclides of the 238U and 232Th series determined in soil profiles and sediment cores from Taiaçupeba reservoir, São Paulo, Brazil
2016 - SOUZA, JOSEILTON M.; DAMATTO, SANDRA R.; LEONARDO, LUCIO; SURKOV, ANDREY M.; SILVA, ANDRE R.; MADUAR, MARCELO F.; GONÇALVES, PEDRO N.