Re: Radioactive Material Thresholds

[simpsoj@citec.qld.gov.au (John Simpson)]

In Australia the Queensland Act is more antiquated (1958-78) than the NSW
version and still uses Curies for deinitions of what constitutes a
radioactive substance. Written ofcourse in appalling legalese, my
understanding is that a concentration of more than 0.002 micro-curie per
gram of any substance is required before any substance is classed as a
radioactive substance. Then depending upon the isotope (grouped into 4
categories as with the NSW act)there is a total activity level threshold
which is equivalent to the NSW version measured in micro-curies. For any non
categorised isotopes the threshold is 10 micro-curies.

The UK 1985 ionising radiations regulations defines a radioactive substance
as any substance with an activity concentration of > 100 Bq/g and any
substance whose activity can not be disregarded for the purpose of radiation
protection.

John Simpson
Director of Medical Physics
Townsville General Hospital
Queensland, Australia
simpsoj@citecuf.citec.qld.gov.au