Application of radiochemical methods and dispersion model in the study of environmental pollution in Brazil

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 for^239+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.