Environmental gamma and radon dosimetry in Venezuela

摘要

Environmental gamma exposure and radon concentration levels measured in Venezuelan regions are presented. A new generation image analyser was used for a particle track counting in CR-39 detectors. Mineral water wells from where 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 potable water activity is on the average around 5.3 +/- 12% Bq L-1. Indoor radon national average is 36 +/- 5% Bq m(-3); in two of the 36 monitored sites, the measured average is above 400 +/- 5% Bq m(-3). In air gamma dose values are between 100 and 144 nGy h(-1). In soil, Cs-137 concentration is around 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 concentration in tropical plants on Tepuy-s (sacred mountains in the Amazonas State). Geological active faults were identified by radon concentration measurements using LR-115. [References: 7]