Jen Barnes is a radiological consultant and RPA at Jacobs . In this article she discusses the radiation protection issues associated with the historical use of radium , which became widely used for industrial purposes and in consumer products following its discovery by Marie and Pierre Curie in 1898 .
Radium has 33 known isotopes , all radioactive , of which Ra-226 ( half-life 1,600 years ) is the most stable . It occurs naturally as a decay product of U-238 , and decays by alpha emission to its daughter product radon-222 , which is a radioactive gas . If the gas does not escape , the decay products of Rn-222 ( half-life 3.8 days ) can be used to identify the presence of radium .
Radium was initially heralded as a ‘ wonder substance ’ of benefit to human health , claimed to cure everything from constipation to cancer and adding a bit of ‘ zing ’ to the elderly . In the early 20th century it became a popular ingredient in consumer products such as cosmetics , toothpaste , shampoos , ‘ tonic water ’ and even chocolate . Radium was also widely used to make self-luminous paint that was used on watches , clocks and aircraft instrument dials – and famously caused serious and often fatal health effects for the ‘ Radium Girls ’ who used to lick their brushes as they painted the dials . These women suffered from chronic exhaustion , anaemia , bone fractures , tooth decay , had still-born babies and developed ‘ radium jaw ’ due to necrosis .
When the detrimental health impacts of significant radiation exposure became recognised , the inclusion of radium in products such as chocolate and make-up was thankfully discontinued - although you can still buy old ‘ Tho-Radia ’ products on eBay ( a favourite hobby of a friend of mine who shall remain nameless …) but the use of radium in self-luminous paints continued until the early 1970s .
One of the main ways the radiation protection community now comes across radium is in the remediation of locations with legacy radium items or contamination from historical activities . This might be when decontaminating premises that previously housed a radium luminising workshop , surveying old airfields prior to development , disposing of legacy sources from schools or museums , retrieving radium particles that have been released from an old disposal site following incineration and burial , or even cleaning up Ernest Rutherford ’ s old university desk !
1921 advertisement for Undark luminous paint
One hazard to be managed during the cleanup of radium contamination is worker exposure to radon gas , especially in old facilities that lack good ventilation . Real-time
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20 Radiation Protection Today www . srp-rpt . uk