Environmental gamma and radon dosimetry in Venezuela

Environmental gamma exposure and radon concentration levels measured in Ven ezuelan regions are presented. A new generation image analyser was used for a particle track counting in CR-39 detectors. Mineral water wells from whe re water is supplied for massive consumption have an alpha activity around 0.450 Bq L-1 and few of them have concentrations above 50 Bq L-1. Coastal p otable water activity is on the average around 5.3 +/- 12% Bq L-1. Indoor r adon national average is 36 +/- 5% Bq m(-3); in two of the 36 monitored sit es, the measured average is above 400 +/- 5% Bq m(-3). In air gamma dose va lues are between 100 and 144 nGy h(-1). In soil, Cs-137 concentration is ar ound 0.5 and 10 Bq kg(-1) at the depth of down to 20 cm. Building materials were included in this study. Be-7 and Cs-137 were measured in low concentr ation in tropical plants on Tepuy-s (sacred mountains in the Amazonas State ). Geological active faults were identified by radon concentration measurem ents using LR-115.