DETECTION LIMITS OF ABSORBED DOSE OF IONIZING-RADIATION IN MOLLUSCAN SHELLS AS DETERMINED BY EPR SPECTROSCOPY

The exposure of waters to ionizing radiation from radionuclides impris oned in dumped nuclear waste containers, freed in nuclear submarine ac cidents or released in underwater magma eruptions are difficult to be evaluated by conventional radiometric methods. Ionizing radiation evok es stable paramagnetic centers in crystalline lattice of mineral compo nents in bone skeletons of mammals and fishes as well as in exoskeleto ns of mollusca. They give rise in e.p.r. to Specific, extremely stable signals which are proposed to be applied as indicators of radiation e xposure levels. In present study the e.p.r. detection limits of the do se of ionizing radiation absorbed in shells of fresh water and marine mollusca (selected species) have been estimated. It has been found tha t with fresh water mollusca the dose of 1-2 Gy can be detected, while the sea water mollusca by one order of magnitude lower, i.e. about 0.1 Gy.