We examined removal efficiency of radioactivity from radioactive organic liquid waste by active charcoal or by salting out. Hydrophilic organic liquid was treated by active charcoal. More than 90% of radioactivity of radioiodine in hydrophilic organic liquid was removed by powdered active charcol packed in a paper bag. Hydrophobic organic liquid was treated by salting out with aqueous saturated NaCl solution and the removal percentage (%) of radioactivity of hydrophilic radiolabeled compound and vaporizable decomposition products in hydrophobic organic liquid was more than 90%, however that of hydrophobic radiolabeled compound was only 6.1%. Radioactivity in saturated NaCl after salting out was efficiently removed by active charcoal packed in a paper bag.
A smear measurement system for a low-energy β emitter has been developed, which uses a paraffin scintillator for a radiation detector. In sample preparation, the radioactive contamination on a smear sample can be solidified immediately by adding small amount of a liquid-solid reversible paraffin scintillator. This technique overcomes many disadvantages of a conventional liquid scintillation technique ever employed, and allows the smear sample to be measured repeatedly and stored.