OBJECTIVE: The objective of this study was to perform a passive and time-integrated radon monitoring in several soil and water samples and indoor environments of the São Vicente, SP, rock massif with the purpose of evaluating the presence and distribution of that radioactive gas in this region. MATERIALS AND METHODS: The technique employed consisted of exposing Makrofol E-type polycarbonate plastic detectors (SSNTD), using the closed cup method, to radon emanated from ground water samples and to the gas accumulated inside indoor environments (dwellings) and inside rock cavities existing in the São Vicente rock massif. RESULTS: The radon concentration values obtained ranged from 8.1 to 36 Bq/l in natural ground waters; between 68 and 610 Bq/m³ in dwellings; from 0.41 to 3.46 kBq/m³ in soils and from 0.72 to 5.85 kBq/m³ inside rock cavities of the São Vicente rock massif. CONCLUSION: In some dwellings and in most of ground water samples, the radon concentration values found in this study have exceeded the maximum levels proposed by international agencies. Thus, intervention actions are recommended for radon dissipation in dwellings and during consumption water collection.
Radon; Natural radioactivity; Nuclear track detectors; Environment; Uranium
