Assessment of effective doses from radon levels for tour guides at several galleries of Santana Cave, Southern Brazil, with CR-39 detectors: preliminary results.

Indoor radon concentrations have been measured in Santana cave, the most frequented cave of PETAR (High Ribeira River Tourist State Park), situated southern of Sao Paulo State, Brazil. The measurements were carried out with CR-39 detectors installed in four of the most frequently visited galleries. Preliminary results from November 2009 to June 2010 show radon concentrations varying from 1.9 ± 0.1 to 8.4 ± 0.6 kBq m(-3). The total annual effective dose for all galleries was 3.32 mSv. The complete evaluation will be concluded by September 2010.