<p>RADIATION SOURCES – RISK ASSESSMENT</p><p>Risk assessment for teachers using radioactive sources in class The following practices can be employed to reduce the exposure of radiation emitted by radioactive sources used in teacher demonstrations: </p><p>1. Minimise time – minimising the time spent around a source of radiation will reduce the total exposure to radiation. 2. Maximise distance – maximising the distance from a source of radiation will reduce the total exposure to radiation. Radiation levels decrease rapidly with distance due to the inverse square law, so even small increases in distance can have a large impact on reducing the total radiation exposure. Radiation is also absorbed by air and other particles/materials. The further you stand away from the radioactive source the less exposure will occur. 3. Use shielding – staying behind the shields as much as possible will reduce the total exposure to radiation. Lead and concrete are good absorbers of radiation, particularly the most penetrating, gamma rays.</p><p>Also, a good policy to follow is to use the less harmful  and  emitters and stay away form the more harmful -ray emitters. Sources should be handled with tongs and forceps only. Teachers should be experienced in handling these types of materials. Only teachers and not students should use radioactive materials. Radioactive substances should be stored in lead lined boxes.</p><p>The website <http://www.unimelb.edu.au/rmo/comference/proceedings_part6.pdf> has a broad- scope risk assessment based on radioactive substances by Mr A Barber, Senior Human Resources Officer (Radiation Safety), Health and Safety Advisory Services, Queensland University of Technology. It also includes a protocol for purchasing, handling, storing and using radioactive substances, the radiological risks involved, an assessment of users of radioactive substances and specific data about common radioactive substances used in educational forums and found in educational laboratories including activity type, half life, Emax, range and how to handle them.</p>