Wednesday, 23 March 2011

The radiation bogey man...

As an ex-radiographer I remember being taught to respect and avoid radiation. At work each day we used to put on a radiation monitoring badge which was sent every month to the National Radiation Laboratory in Christchurch where our exposure to what we called scattered radiation was assessed. We wore lead rubber aprons when working with prolonged radiology techniques, and some even wore lead rubber gloves when using old out-dated fluoroscopic equipment. Even today I have some distaste for dental xray techniques and the often cavalier attitudes of dental staff when taking them. Health risks from radiation are real, as the effects over a lifetime are cumulative.
However, in "nuclear-free" NZ, the militant anti-US brigade have succeeded in inducing hysteria among the general population over all nuclear issues. Food irradiation for example, to prolong shelf life was mooted and rejected with allegations of "frankenfood" mutations possible. Nuclear propelled ships are not allowed in our harbours because some feel they may become transformed into nuclear explosions.

A healthy respect for radiation is to be aware of its dangers, yet embrace its benefits. Much as we do with electricity and petrol. With this in mind I am delighted to see from a Mr Randall Munroe, a Radiation Dose Chart illustrating the wide range of radiation we may experience or hear about in a lifetime; from sleeping next to someone (0.05 micro-sieverts) to a flight from New York to LA (40 micro-sieverts) to the maximum yearly dose permitted for US radiation workers (50 milli-sieverts)...full chart here...

Another illustration of comparitive radiation exposures compares radioactive seepage of naturally occuring radon gas from rock...Radiation exposures in highly publicized nuclear accidents are thus considerably lower than those received by people in these (high radon) areas every day. Note that the Pennsylvania area includes the region around the Three Mile Island plant; people living near that plant get more radiation exposure from radon in their homes every day than they got from the 1979 accident. Within any area, there is a wide variation in radon levels from house to house. About 5% of us, 12 million Americans, get more than 1,000 mrem (1 mrem = 0.00001 Sv = 0.01 mSv = 10 ╬╝Sv ) per year, and perhaps 2 million Americans get over 2,000 mrem per year from radon. In a few houses, exposures have been found to be as high as 500,000 mrem per year...more here...

Radiation is and always has been part of all our lives. Its peaceful usage in medicine and in modern well controlled nuclear power plants will remain and help drive modern society into a more prosperous and safer future - Fukushima, Three Mile Island, Windscale and Chernobyl notwithstanding...hat tip PKH

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