Abstract
Under the Law Concerning Prevention from Radiation Hazards due to Radioisotopes etc., the radioactive dry solid waste is composed into drums at an on-site warehouse until collection and disposal at the storage facility of the Japan Radioisotope Association (JRIA). The radioactivity levels of such dry solid waste that have been previously assumed and recorded by the experimental researchers have sometimes been in error. A methodological approach was investigated for re-evaluation of radioactivity in dry solid waste, prior to shipment to the JRIA for future disposal at a landfill site. The radioactivity of 51Cr-and 125 I-contaminated wastes generated from biomedical research was measured. In the 51 Cr-contaminated wastes, the measured radioactivity always showed higher values, ranging between 1.4 to 9.9 times that of the recorded radioactivity.In the 125I-contaminated wastes, 4 of 5 combustible type 2 samples showed 4.1 to 28.6 times higher measured radioactivities than those initially recorded. The ratio of measured versus used radioactivity was also evaluated. This study may contribute a fair assessment of the radioactivity levels in biomedical waste prior to shipment to the disposal sites, and thus afford protection of human health and the environment.
