POTENTIAL HEALTH HAZARD The significance of the levels of radioactivity in environmental samples published in this Report may be understood more readily by comparing these levels with the following "permissible levels for the general population" which have been adopted for use in New Zealand. These levels have been set as a guide to limit the controlled release of radioactive substances into the environment by licensed users in New Zealand. They are levels which individually would not require remedial or preventive action and have been chosen to protect the most sensitive age group in the population, It is considered that any risk associated with these levels is exceedingly small and that levels many times as great would involve ~ a hazard which is small compared to commonly accepted risks of life. "Permissible levels" of Radioactivity These levels were derived so as to ensure that the dose to any member of the public arising from the controlled use of radioactive materials does not exceed the Dose Limit recommended by the International Commission on Radiological Protection. Strontium-90 In Milk: In Bone: : 270 Strontium Units - maintained indefinitely in the milk. 67 Strontium Units. Caesium~-137 In Milk: 7,000 pCi/g K - maintained indefinitely in the milk. Todine-131 In Milk: 200 pCi/litre - as an average intake over one year. Total Beta Activity of Mixed Fission Products Between 10 and 80 Days 01d In Air: 300 pci/m? - for continuous breathing. In Rainwater: 6,000 pCi/litre - for continuous consumption. Iti = 5