In Vivo Gammaspectrometric Investigation of Thorium Body Burdens in the Egyptian Monazite Area

In this paper thorium body burdens in the Egyptian monazite area have been investigated using a whole body counter provided by a 4 in. × 8 in. NaI(Tl) crystal. In the course of analysing the results, it was assumed that 232Th which is initially 100 in equilibrium with its daughters reaches a steady state of 40–50 equilibrium in the body due to the metabolic effects. The measurements have been performed for the inhabitants of Rosetta as well as workers of the Egyptian black sand refinery plant. The detection sensitivity for a single individual worker or inhabitant was 3.04 nCi and 3.01 nCi respectively. Treating each group as statistically equivalent, the minimum detectable activity was 0.8 and 0.93 nCi respectively. However no activity in either case was found.