RE: Fwd: Hot playground?

[jgbarnes@ix.netcom.com (JAMES BARNES)]

Dear Ms. Cartnell,

I passed your concerns along to Mr. Bob Tuttle.  Mr. Tuttle is the former manager 
of Atomic International's (now Rocketdyne's) Radiation Protection Department.  He 
is currently serving as a consultant to the division for environmental 
radioactivity.  Is is Certified by the American Board of Health Physics.

Jim Barnes, CHP
Radiation Safety Officer
Rocketdyne Division; Rockwell Aerospace
jgbarnes@ix.netcom.com
(818)-586-5766
==============================================
Bob Tuttle's reply: 
>
>
>I think the key to rational consideration of this situation lies in 
>understanding occupancy and relative risks.  Working against this is the 
>natural overwhelming desire to protect children (unless it takes very much 
>effort) and the widespread occurence of radiophobia.
>
>While we consider children to be more susceptible to radiation-induced harm 
>(cancer, particularly leukemia), by a convenient factor of 10 compared to 
>adults, a child's exposure at a playground is likely to be very limited. 
> Considering the locale, I suspect that essentially no exposure occurs in 
>the winter, either because of snow cover or because of the extreme cold 
>keeping children indoors.

>Depending on the availability of the school property, exposure may be prevented 
during the summer vacation?  Use of the playground may be 1 or 2 hours a day, 
weekdays, perhaps March-April-May-June and September-October-November.  This 
would be about 150-300 hours per year, or about 1/10 of an occupational work 
year.  If this is a 6-year grammar school, the exposure is likely to be no more 
than 6 years, less if people move around like they do here.  Upper schools are 
likely to have shorter and even less intensive occupancy.  Exposure to radon is 
not likely to be significant since the site is outdoors, and any radon from the 
ore will be well diluted by the wind.  Further, unless this is a high school, few 
of the children are likely to be cigarette smokers, and that is the real cause of 
lung cancer.

>Grass cover or paving, which would reduce airborne dust, would 
>essentially eliminate internal exposure, except for the few dirt-eaters or 
>the soil-grubbers who bite their nails.  The contact reading of 
>700-800 microR/hour on contact is not directly relatable to external 
>exposure.  A better measure would be exposure rate a little lower than a 
>child's waist, or at ground level.  Our exposure rate at 1 meter above the 
>ground is 15 microR/hour, somewhat higher than that in Ontario.
>
>Radiation risks are calculated based on a linear (direct proportionality) 
>model, and can be produced with impressive precision (not accuracy).  For 
>low exposures, such as the playground, this model is almost certainly wrong, 
>greatly overestimating the calculated risk.
>
>Accidents happen to children in playgrounds.  Children catch illnesses in 
>playgrounds.  Sometimes these accidents and illnesses are even fatal.  The 
>probabilities of such fatalities are extremely low, but so is the risk of 
>any harm from radiation exposure from the playground, if I understand the 
>situation properly.  My greater concern would be the instilling of excessive 
>fear for low-risk hazards in the environment:  fear can so badly spoil the 
>quality of life.
> ----------

Your original message:

>From: ljc@wbb.com
>To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
>Subject: Hot playground?
>
>I would appreciate the comments of medical and scientific
>professionals with regard to Surface Gamma Radiation levels recorded
>on a school playground located in Ontario, Canada. The school was
>built near the site of a plant which, during World War II, created
>high levels of radiation. A substantive volume of radioactive soil
>has been removed from residential properties in the area.
>
>One piece of Uranium ore recovered from the playground gave a
>Radioactivity reading of from 700-800 micro R/h on contact. The known
>range of background gamma radiation in southern Ontario is from 2.5 to
>10 micro R/h.
>
>Uranium results for a soil sample taken in the area where the ore was
>recovered gave a measurement of 65.11 ppm. The Ontario Typical Range
>is given as being 1.9 to 2.1 ppm for uranium in soil. The radium
>result for the soil sample was 3.49 pCi/g, which is more than twice
>the Upper Limit Normal for this area of 1.5 pCi/g.
>
>My question is this: Do readings such as those I've presented create
>any basis for health concerns on the part of those using a
>playground? Can scientists suggest acceptable levels of radiation and
>uranium in surface soil for a school property, or are there *no*
>demonstrably safe levels for such an environment?
>
>As a lay person I would appreciate informed comments. Thank you very
>much.
>
>Lori Cartmell.
>
>(ljc@wbb.com)
>
>
>