![]() ![]() This paper indicates a health risk, particular to collectors, but with knowledge and appropriate precautions the potential risks can be reduced.Ĭopyright © 2012 Elsevier Ltd. The risk from old watches containing radium appears to have been largely forgotten today. Estimates of the activity of (226)Ra in the watches ranged from 0.063 to 1.063 μCi (2.31 to 39.31 kBq) for pocket watches and from 0.013 to 0.875 μCi (0.46 to 32.38 kBq) for wrist watches. Over 6 weeks highs of the order of 2000 Bq m(-3) were routinely recorded when the heating/ventilation system in the room was operating at reduced rates, peaking at over 3000 Bq m(-3) on several occasions. Workers who used their lips to bring the. Then in 1920, she was headhunted to train dial painters, and returned to radium. She took a job in the office of a roller-bearing company. Others, like Katherine Schaub and some of her friends, left in search of more stable employment. Radon concentration average was 259☙ Bq m(-3) over 16 h, compared to background average over 24h of 1.02 Bq m(-3). Radium paint is used on the dials of watches and faces of clocks. Though demand was still through the roof, the company dismissed a number of dial painters. All watches were placed in a room with a RAD7 real-time radon detector. Radium ((226)Ra) decays to the radioactive gas radon ((222)Rn), and atmospheric radon concentration measurements taken around a pocket watch in a small sealed glass sphere recorded 18,728 B qm(-3). The maximum skin dose from a wristwatch was 14 mSv, with 4.2 mSv effective dose in vest pocket. This assumes exposure from the back of the watch which is generally around 60-67% of that from the front. For this condition we estimated maximum skin dose for our pocket watches as 16 mSv per year, with effective doses of 5.1 mSv and 1.169 mSv when worn in vest and trouser pockets respectively. There was roentgenographic evidence of radiation changes in almost the entire skeleton. The first sarcoma originated at one such site, and microscopic evidence of early sarcoma was found in at least one other. A phantom experiment using a TLD suggested an effective dose equivalent of 2.2 mSv/y from a 1 μCi (37 kBq) radium dial worn for 16 h/day throughout the year (dose rate 0.375 μSv h(-1)). Autoradiography of the bones of the amputated leg showed that radium was still concentrated at the sites of the former epiphyseal plates. Eighteen wristwatches have also been assessed, but their dose rates are generally much lower (the arithmetic mean being 3.0 μSv h(-1)), although the highest ambient dose equivalent rate noted was 20 μSv h(-1). A pocket compass gave rise to a similar ambient dose equivalent rate, of 20 μSv h(-1), to the pocket watches, with its cover open. ![]() Ambient dose equivalent rates have been measured for fifteen pocket watches giving results of up to 30 μSv h(-1) at a distance of 2 cm taken with a series 1000 mini-rad from the front face (arithmetic mean ambient dose equivalent for pocket watches being 13.2 μSv h(-1)). This study re-examines the risk to health from radium ((226)Ra) dial watches. ![]()
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