Authors:J. Torres, S. Olivares, D. De La Rosa, L. Lima, F. Martínez, C. Munita, and D. Favaro
Adsorption of mercury(II) and methylmercury by two tannin sorbents was investigated using radiotracers. High sorption capacities
for mercury are registered for both sorbents at pH 7. ForEucaliptus Saligna Sm sorbent (ETS) the maximum sorption capacity was 1.2±0.2 mmol/g and forLysiloma latisiliqua sorbent (LTS) was 8.5±0.2 mmol/g. Methylmercury adsorption maximum was recorded at pH 4 and in buffered solutions at pH2.
This species can be recovered in the presence of mercury(II). Influence of different ions present in water was examined. High
recoveries were reported for ETS in tap water samples but a decrease of uptake is observed for seawater.
Authors:D. Fávaro, V. Maihara, D. Mafra, S. Souza, M. Vasconcellos, M. Cordeiro, and S. Cozzolino
In the present work, the concentration of the 14 elements Br, Ca, Cl, Co, Cs, Fe, K, Mn, Na, Rb, Sc Se and Zn have been determined by INAA in diets of four different groups: (a) 19 pre-school children, (b) 18 healthy adults, (c) 23 elderly people living in private institutions and (d) 19 patients with chronic renal failure (CRF). The contents of proteins, lipids and carbohydrates were also analysed in the diets. The daily intakes of the elements analysed were compared to the recommended values set by RDA or WHO.
Authors:D. Araripe, A. Bellido, S. Patchineelam, R. Latini, L. Bellido, and D. Fávaro
The Itingussú drainage basin is situated at 22°44′–22°55′ SL and 44°53′–43°55′ WL, in Coroa-Grande district, Sepetiba Bay,
southwest of Rio de Janeiro, Brazil. Its total area is less than 10 km2 and includes a waterfall with three drop offs. The study area is located in a granitic pre-Cambrian embasement, discharging
in a mangrove forest fringe. This work attempts to investigate the influence of lithology types in the elemental composition
of soil of region and sediments of related mangrove. Instrumental neutron activation analysis and subsequent gamma-ray spectrometry
were used. This technique enabled the measurement of at least twenty-one chemical elements. The more representative soil samples
were enriched with U and Th. Multivariate Statistical Analysis showed that the soil and sediments formed in this area have
been influenced by the leucocratic rocks, enriched with LREE and Th. The factorial analysis enables the identification of
five factors of influence in the ordination of elements: presence of iron minerals (biotite); presence of allanite; marine
influence in the sediment; differentiated kinetic of transport and diagenesis.
Authors:C. Gonçalves, D. Fávaro, S. De Oliveira, R. Boulet, M. Vasconcellos, and M. Saiki
This study presents preliminary results on mercury distribution, released by gold mining activities, in soils from Vila Nova
River region, an area located in Serra do Navio, Amapá, in the Brazilian Amazon. The soil samples were separated in two grain
sizes, sand (between 2 and 0.063 mm) and silt+clay (<63 μm), and have been analysed by radiochemical neutron activation analysis.
The precision and accuracy of the method were verified by means of the reference material analysis GXR-5 (USGS).
Authors:P. S. C. Silva, B. P. Mazzilli, and D. I. T. Fávaro
Cubatão River is located in Santos Basin, São Paulo State, Brazil. This region is characterized by the occurrence of estuaries
and mangrove. Due to its location, near the coastal line, it is also an important industrial area, where phosphate fertilizer
plants, petrol refineries, and chemical and steel industries are present. Such human activities contribute to the enhancement
of elemental composition in sediments and, in some cases, also increase the radionuclide concentrations, the so called Technologically
Enhanced Natural Occurring Radioactive Materials (TENORM). The contamination of land and sediments by TENORM is of major concern.
The activity concentration of U and Th series radionuclides was determined in five sediment samples from Cubatão River. The
activity concentration ratio was also determined. Equilibrium was observed for the ratio 234U/238U. The activity ratios of Th/238U, 228Ra/226Ra and 210Pb/226Ra were higher than the unity. In the first two cases, the observed values are due to the higher activity of Th in the sediment
and in the last case are probably due to the atmospheric deposition of 210Pb.
Authors:G. Lalor, M. Vutchkov, C. Grant, J. Preston, A. Figueiredo, and D. Favaro
The biological standard reference materials Orchard Leaves SRM 1571 and Oyster Tissue SRM 1566a was analysed by instrumental neutron activation analysis (INAA) at the International Centre for Environmental and Nuclear Sciences, Jamaica at (ICEN) and at the Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Brazil. The comparison of the results with those obtained with the more powerful reactor are used to evaluate the possibilities of INAA for the analysis of biological samples at ICENS. The detection limits, the precision and accuracy of the results obtained in both laboratories are compared. The advantages and disadvantages of the different irradiation facilities are discussed. Some results obtained for Jamaican biological samples are also presented.
Authors:S. Oliveira, F. Larizzatti, D. Fávaro, S. Moreira, B. Mazzilli, and E. Piovano
Using instrumental neutron activation analysis, the vertical distribution of La, Ce, Nd, Sm, Eu, Tb, Yb and Lu was determined in 3 well dated sedimentary cores collected from Laguna Mar Chiquita, Argentina. Validation of the methodology was done using the Soil 7 (IAEA) reference material. The REE contents vary according to core location and lithological units, depending on the proportion of fluvial terrigenous components in the lake sediments. Lithologies with higher proportion of terrigenous components show higher REE concentrations, suggesting that the dominant REE carrier phase might be a detrital mineral. There is a consistent value of about 1.2 for (La/Yb)N and (LREE/HREE)N ratios for all sediments at the three sites, indicating a slight LREE enrichment in relation to the average shale NASC. Ce/Ce* values are close to 1.0, meaning that Ce behaves similarly to other light REE's.
Authors:M. Vasconcellos, M. Saiki, D. Fávaro, V. Maihara, A. Figueiredo, and M. Catharino
The Research Reactor Center (CRPQ) of IPEN/CNEN-SP operates the IEA-R1 Research Reactor, at a nominal power of 2 MW thermal,
on a 64 hour per week continuous cycle. The IEA-R1 is a pool type reactor, moderated and cooled by light water, with graphite
as a reflector. One of the main activities of CRPQ is the neutron activation analysis, which is applied to many fields of
research, in collaboration with other institutes and universities. The Research Reactor installations are also intensely used
for human resources development in the field of radiochemistry and neutron activation analysis, at graduate and post-graduate
levels. In the present paper, an overview will be presented of some of the neutron activation analysis research lines that
are being developed, comprising environmental and health-related applications.
Authors:V. Maihara, I. Gonzaga, V. Silva, D. Fávaro, M. Vasconcellos, and S. Cozzolino
Due to its essential characteristics, the daily dietary selenium intake of individuals should be monitored accurately. In
the current work, daily selenium intake of different Brazilian population groups based on duplicate portion diet analysis
was evaluated and compared with the new estimated average requirement values (EAR), to assess if selenium deficiency or excess
could be observed in these groups. Selenium content was determined by neutron activation analysis (NAA). The average daily
dietary selenium intake found was 26.3 (±8.3) ·g/day for children from the city of São Paulo, 37.4 (±16.0) ·g/day for children
from Belém, 107 (±107) ·g/day for children from Macapá, 28.4 (±7.5) ·g/day for institutionalized elderly, 32 (±6) ·g/day for
non-institutionalized elderly and 37 (±17) ·g/day for university students from São Paulo. Most daily dietary selenium intake
range observed were below the EAR values. The values obtained for children groups from Belém and Macapá cities, whose intake
levels were much higher than the recommendation, were an exception.