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Radon and progeny are potentially relevant in radioecological studies, as they contribute more than half of the exposure to environmental radiation. The investigation of 222Rn in internal environments of municipalities of Paraíba and Rio Grande do Norte in Brazil was carried out using passive dosimetry with α Espec-222, installed in environments selected by the history of natural radiative occurrences. The monitoring time was eight months to consider seasonal influence. Concentrations from 26.91 to 316.35 Bq m-3 were obtained, with a maximum effective dose of almost 8 mSv y-1. The influence on households exceeds, by almost 31%, the average obtained for occupational environments. The municipalities of Paraíba presented higher results for Rn, with an average of almost 176 Bq m-3 and an effective dose greater than 4 mSv y-1. The application of individual occupancy factors for home and work environments made it possible to combine the dosimetric models, making the scenario closer to the real exposure of individuals who work and reside in the same municipality, with a dosimetric response of 21.45% lower than the model used worldwide. The different scenarios applied allowed expanding the radiometry of the environments, generating a database that precedes studies of environmental and radioecological impacts, strengthening security and enabling new works to interpret public health problems in search of joint and shared solutions. • Indoor radon flux was used to calculate radioecological risk. • The study shows high levels of radon indoors in areas with NORM. • Passive dosimetry was used to diagnose airborne radon levels and environmental impact. • Different situations were used to calculate the risks arising from radon exposure. • The number of cancer cases and estimated deaths in the region impacted by radon were calculated. [ABSTRACT FROM AUTHOR]

Radon is important in indoor radiometry, where radiological impact is relevant. The improvement of low-cost methods makes it possible to maximize the monitored areas. Thus, a simple and robust monitoring device based on SSNTD CR-39 was designed. Detector conditions were standardized to reduce operational errors and increase productivity. The calibration factor by the slope method allowed efficiency greater than 93%. The monitoring system is satisfactory in terms of operation and performance, suitable for a wide range of radon monitoring situations. • An air diffusion chamber (α SPEC-222) for use with a CR-39 SSNTD was developed for radon measurement. • The calibration factor was obtained by the angular coefficient method, the efficiency was higher than 93%. • The method was tested, validated, and applied in a case study to test the functionality of the spectrometer. • The measurement system is sensitive and capable of integrating response from low values to anomalous levels. [ABSTRACT FROM AUTHOR]

The Metropolitan Region of Recife and its surroundings are heavily exploited to capture water for public supply through tubular wells. However, a survey of the levels of natural radionuclides from these sources had never been carried out, even though part of this region contains a phosphate deposit that has a high concentration of natural uranium. In this context, this research aimed to identify 228Ra and 226Ra levels in groundwater in the coastal region of Pernambuco, Brazil. About 110 points (wells) of drinking water for public supply were identified and studies were carried out to estimate the level of ingestion and subsequent risk due to the presence of this radionuclide. The average concentration of combined radium was 104 mBq.L−1. For 228Ra an effective dose of 0.46, 0.11, 0.12 and 0.0276 mSv.y−1 for infants, children aged 1 and 10 and adults, respectively, were obtained. Although doses above those recommended by WHO were found, the equivalent dose and the induction of bone sarcoma did not indicate a risk to the population. Groundwater with higher dose values is influenced by local geology. • The activity concentration of 228Ra and 226Ra in groundwater used for public supply was determined. • The effective dose for infants and children exceeded five and two times, respectively, the value recommended by the WHO. • A strong correlation was observed between the hot spots and the geology of the area. [ABSTRACT FROM AUTHOR]