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  • Author or Editor: R. Figueira x
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Abstract  

A radiochemical procedure for low level strontium-90 analysis in fish samples as well as the levels of this radionuclide in fish collected along the Brazilian coast are presented. The method developed was applied in reference samples from the IAEA in order to verify the precision and accuracy of the methodology established. Results obtained for strontium and yttrium yields were about 90%. Strontium-90 levels in fish bones varied from 3 to 12 mBq.g–1 Ca and these data are reference values to our country.

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Abstract  

Methodologies for analysis of anthropogenic and natural radionuclides in marine samples were developed and applied in environmental samples. Results of systematic measurements of these radionuclides have showed that artificial radioactivity levels are in agreement with the values from the regions not affected directly by nuclear accidents or nuclear reprocessing plant discharges and are due to the global fallout. The average concentration of137Cs is of 1.4 Bq·m−3 in seawater, ranges from 13 to 220 mBq·kg−1 in fish, and from 0.4 to 1.8 Bq·kg−1 for sediments.90Sr levels in seawater are of 1.8 Bq·m−3 and in fish vary from 19 to 75 mBq·kg−1. Sediments present concentrations of90Sr lower than 0.8 Bq·kg−1 and for239+240Pu of 0.03 to 0.18 Bq·kg−1.210Po levels in fish range from 0.5 to 5.3 Bq·kg−1. The data generated represent reference values for our country and are used to estimate the intake levels of these radionuclides by consuming of marine products.

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Abstract  

The137Cs radionuclide dispersion in the marine environment through the compartmental model is reported. The model simulates the surface water contamination caused by routine or accidental radionuclide releases. For the simulation the OCEAN program was applied in the North Sea, near to Sellafield and adjacent areas, based on published transfer coefficient data. The results are in good agreement with the literature and the model developed can be applied to the brazilian coastal regions.

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Abstract  

Methodologies for simultaneous analysis of 137Cs, 90Sr, 238Pu and 239+240Pu were developed and applied to seawater samples. 137Cs levels in Brazilian coastal seawater ranged from 0.12 to 4.7 Bq·m-3, for 90Sr from 2.0 to 8.6 Bq·m-3, for 239+240Pu from 0.8 to 4.5 mBq·m-3 and for 238Pu it was of 1.9 mBq·m-3. The artificial radioactivity levels in Brazilian seawater are typical values due to fallout deposition.

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Abstract  

The olive tree (Olea europaea) is an icon of southern Europe and awidespread evergreen in mainland Portugal. First results of a continuing studyon the ability of olive-tree bark to act as an air-pollution biomonitor arepresented and discussed here. Other than lower signals and an anticipatedsystemic control over some elements, there seems to be no a priori reasonfor ruling out the possibility of using bark in atmospheric trace-elementsurveys. In fact, nonparametric statistics show that, despite their relativemagnitude, the variation patterns of bark and lichen concentrations significantlyfollow one another all across the study area.

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Abstract  

Arsenic and cadmium contents in eight edible mushroom species (Agaricus bisporus, Agaricus sp, Pleurotus ostreatus, Pleorotus florida, Pleorotus eryngui, Pleurotus osteatus, Pleurotus salmoneostramineus, Lentinula edodes) consumed by Brazilian population were determined by instrumental neutron activation analysis (INAA) and graphite furnace atomic absorption spectrometry (GF AAS), respectively. Arsenic concentrations varied from 0.009 mg/kg in P. eryngui to 0.210 mg/kg dry weight in L. edodoes and Cd from 0.011 g/kg in P. eryngui to 0.229 mg/kg dw in P. salmoneostramineus. The consumption of mushrooms in São Paulo-Brazil may be considered safe from a toxicological point of view as As and Cd presented levels of ingestion are below the maximum levels recommended by the World Health Organization.

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Summary  

Guanabara Bay, located at Rio de Janeiro, is an example of an impacted coastal environment due to the high influx of industrial and domestic effluents. Four sediment cores were sampled in areas with different levels of pollution and were analyzed for trace elements and foraminifera for abundance. Instrumental neutron activation analysis (INAA) was used to determine As, Ba, Co, Cr, Fe, Sb, Sc, and Zn. The effects of metal concentrations in the benthic foraminifera were studied. The low concentrations of the benthic foraminifera and the dominance of opportunistic species in coastal regions such as Ammonia may be correlated to natural stress or anthropogenic impact.

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