RESUMO
(129)I and (127)I concentrations in animal thyroids coming from several regions of Argentina were determined by accelerator mass spectrometry (AMS) and gas chromatography (GC), respectively. The measured (129)I/(127)I ratios, ranging from 3 × 10(-12) to 4 × 10(-10), are significantly lower than those typical for areas in the northern hemisphere (10(-10)-10(-7)). The (129)I concentrations show a clear dependence with latitude and season, which can be understood considering tropospheric circulation patterns, possible (129)I sources and regional precipitation rates.
Assuntos
Poluentes Radioativos do Ar/análise , Exposição Ambiental , Iodo/análise , Glândula Tireoide/química , Animais , Argentina , Bovinos , Cromatografia Gasosa/veterinária , Monitoramento Ambiental , Radioisótopos do Iodo/análise , Espectrometria de Massas/veterinária , Estações do AnoRESUMO
Concentrations of (210)Pb and (137)Cs in sediment samples collected from two cores at a drainage channel to the La Plata river estuary in Buenos Aires, Argentina, were measured using ultralow-background detection systems. The (210)Pb data were used to determine the rate of sediment accumulation of the sites. These results were correlated with some heavy metal (chromium and lead) concentrations of the samples in an attempt to characterize the historical input of contaminants due to the industrial development, which has taken place in this area over the last century. The (137)Cs measurements demonstrate that cesium dating is not adequate in regions of the southern hemisphere.