Radon-222 concentrations were determined in about 100 measuring points
in a uranium-prospecting area in the eastern part of Brazil. The sing
le measurement data in open areas, identified as environmental points,
present values between 4 +/- 2 Bq m(-3) and 404 +/- 16 Bq m(-3), with
a mean value of 69 +/- 6 Bq m(-3). Comparing the mean values for each
measuring site, the values obtained are between 15 +/- 2 Bq m(-3) in
the store room for mineral samples and 245 +/- 7 Bq m(-3) for the cent
ral point AN08 of the prospective mine. Makrofol SSNTD was used for th
e measurements and exposed for 120 day-alternated periods from May 199
2 to May 1994. (C) 1998 Elsevier Science Ltd.