RESUMEN
Located in the south-western part of Brazil, the state of Rio de Janeiro is geotectonically contained within a complex structural province that resulted in the amalgamation of the Western Gondwana Paleocontinent. To undertake an extensive radiological characterization of this complex geological province and investigate the influence of bedrock, soil type and soil chemical-physical characteristics on natural radionuclide levels in soils, 259 surface soil samples were collected that encompassed the main soil types and geological formations throughout the state. Gamma spectrometry analysis of the samples resulted in median values of 114 Bq.kg-1for 40K, 32 Bq.kg-1 for 226Ra and 74 Bq.kg-1 for 228Ra. The median value for 226Ra was similar to the world median value for soils, the 40K value was well below the worldwide value, and that for 228Ra exceeded the world median value. The intense weathering caused by the high rainfall rates and high temperatures may be responsible for the low levels of 40K in the soils, of which the strongly acidic and clayey soils are markedly K-depleted. A soil from a high-grade metamorphic rock (granulite) presented the lowest 226Ra (18 Bq.kg-1) content, whereas the highest levels for 226Ra (92 Bq.kg-1) and 228Ra (139 Bq.kg-1) were observed in a young soil enriched in primary minerals (Leptsol). A lowland soil (Gleysol) showed the highest median of 40K (301 Bq.kg-1). Strongly acidic soils tended to present high amounts of 226Ra, and sandy soils tended to contain low levels of 228Ra. The external radiation dose indicates that the state has a background radiation level within the natural range.
Asunto(s)
Monitoreo de Radiación , Contaminantes Radiactivos del Suelo/análisis , Suelo/química , Radiación de Fondo , Brasil , Radioisótopos de Potasio/análisis , Radiactividad , Radio (Elemento)/análisis , Torio/análisisRESUMEN
The lead (Pb) isotopes ²°6Pb and ²°8Pb are the final products of the radioactive decay of ²³8U and ²³²Th, respectively. Soils in the municipalities of Pedra and Venturosa, Brazil, present high levels of these radionuclides. We hypothesized that forage plants growing in these soils may take up high amounts of Pb and, consequently, intoxicate dairy cows. To test this, we quantified Pb concentrations in 23 forage samples from this region. Pb concentrations varied from 5 to 344 mg kg⻹. The highest values are one order of magnitude above the reported limit, therefore, indicating high risk of Pb contamination for dairy cows.
Asunto(s)
Enfermedades de los Bovinos/epidemiología , Intoxicación por Plomo/veterinaria , Plomo/análisis , Contaminantes del Suelo/análisis , Animales , Brasil/epidemiología , Bovinos , Clima , Industria Lechera , Dieta/estadística & datos numéricos , Exposición a Riesgos Ambientales/análisis , Exposición a Riesgos Ambientales/estadística & datos numéricos , Monitoreo del Ambiente , Monitoreo Epidemiológico , Intoxicación por Plomo/epidemiología , Plantas/química , Suelo/químicaRESUMEN
(210)Pb is widely distributed in the environment. In this context, the aim of this research has been: (1) to determine (210)Pb concentrations in milk and dairy products from farms located in the cities of Pedra and Venturosa in Pernambuco, Brazil; and (2) to calculate the dose due to the ingestion of (210)Pb in these products. The ion exchange resin method was used and the concentration of (210)Pb varied from 62 to 650 mBq l(-1) in fresh milk, from 202 to 1,494 mBq kg(-1) in curdled cheese and from 11 to 253 mBq l(-1) in milk whey. The estimated dose due to ingestion of milk and dairy products in this region was 0.2 Sv, which is at least two orders of magnitude above the maximum recommended levels.
Asunto(s)
Exposición a Riesgos Ambientales/análisis , Contaminantes Ambientales/análisis , Contaminación de Alimentos/análisis , Radioisótopos de Plomo/análisis , Leche/química , Animales , Brasil , Bovinos , Cromatografía por Intercambio Iónico , Clima , Industria Lechera , Monitoreo del Ambiente/métodos , Femenino , Resinas de Intercambio IónicoRESUMEN
The aim of this research was to determine (210)Pb concentrations in forage from farms located in the municipalities of Pedra and Venturosa, in the Brazilian state of Pernambuco, where rolled blocks of mafic rock with a high percentage of U(3)O(8) were found. The concentrations of (210)Pb varied from 2 to 503 Bq kg(-1) in the forage dry matter samples evaluated. Due to the elevated levels of (210)Pb in the forage samples, it is concluded that this radionuclide is highly available to be ingested by dairy cows and this could represent a hazard to the human population due to possible milk contamination.
Asunto(s)
Industria Lechera , Exposición a Riesgos Ambientales/análisis , Radioisótopos de Plomo/análisis , Leche/química , Contaminantes Radiactivos/análisis , Animales , Bovinos , Dieta/estadística & datos numéricos , Plantas/química , Monitoreo de RadiaciónRESUMEN
Vegetables grown with phosphate fertilizer (conventional management), with bovine manure fertilization (organic management) and in a mineral nutrient solution (hydroponic) were analyzed and the concentrations of (238)U, (226)Ra and (228)Ra in lettuce, carrots, and beans were compared. Lettuce from hydroponic farming system showed the lowest concentration of radionuclides 0.51 for (226)Ra, 0.55 for (228)Ra and 0.24 for (238)U (Bq kg(-1) dry). Vegetables from organically and conventionally grown farming systems showed no differences in the concentration of radium and uranium. Relationships between uranium content in plants and exchangeable Ca and Mg in soil were found, whereas Ra in vegetables was inversely correlated to the cation exchange capacity of soil, leading to the assumption that by supplying carbonate and cations to soil, liming may cause an increase of U and a decrease of radium uptake by plants. The soil to plant transfer varied from 10(-4) to 10(-2) for (238)U and from 10(-2) to 10(-1) for (228)Ra.