Re: radon limits

["J. J. Rozental" <joseroze@netvision.net.il>]

chapter 4 is part of the following doc:

Risks Arising From Exposures To Radon Progeny

S. Guy

Alara Consultants cc

4. Dose Limits

Limitation on occupational exposures to radon and its decay products has been

recommended as far back as the 1930's by various authorities. Goodman and Evans

recommended a maximum concentration of radon of 370 Bq.m-3 in uranium mines in 1940.

In the following decade limits were given by various authorities always in terms of radon

concentrations. When the importance of radon daughters was realised exposure limits

were adjusted to reflect this influence but the adjustment was manifest in two different ways

resulting in essentially two standards. The ICRP expressed the limit in terms of radon gas

concentration with some stipulations concerning radon daughters. In the report of

Committee Two (1959) the maximum permissible concentration (MPC) for radon and

radon daughters was given as :

3E-6 (1+ 1000f) uCi.cm-3.

Where f is the fraction of unattached 218Po ions.

Assuming no unattached ions this equates to a maximum average annual radon

concentration of about 1100 Bq.m-3 of radon in full equilibrium with its daughter products.

This value was again recommended in ICRP Publication 24 (1976) however in ICRP

publication 47 (1985) the ICRP set down the new limits published in ICRP 32 (1982).

In the USA the US Public Health Service had introduced the Working Level in the 1950’s

and set a limit at 1 WL which is equivalent to a concentration of 3700 Bq.m-3 of radon in

equilibrium with its decay products.

It should be noted that the limits set down for radon or thoron are referred to as “derived

limits” since they are derived from the primary limits which are expressed as an effective

dose in mSv. The following limits for radon or radon daughter exposures and intakes are

therefore secondary limits.

Note

If you are interested in the complete document I can send you by attachment

 

Considering IAEA document - The IAEA Safety Series Number One, 1958 consider:

Rn-220 + including its daughter products = 10^-7microCi/cm³

Rn-222 + including its daughter products = 10^-7microCi/cm³ 

Jose Julio Rozental

joseroze@netvision.net.il

Israel

----- Original Message -----

From: Jan Skowronek

To: Otto G. Raabe ; Radsafe

Sent: Tuesday, October 29, 2002 11:59 AM

Subject: radon limits

Dear Otto,

I have a G. Akerblom's report to SSI "Radon Legislation and National Guidelines" (SSI Reprt 99:18, Juli 1999, ISSN 0282-4434) where he wrote (page 4):

"... In 1941, the US Advisory Committee on X-Ray and Radium Protecction set 10^-8 microCi/cm³ (370 Bq/m³ EER) as the value of maximum permissible concentration (MPC) for ocupational exposure (40 hr/week) to ²²²Rn, including its daughter products (National Bureau of Standards, 1941: Safe Handling of Radioactive Luminous Compounds. Handbook H27. Superintendent of Documents, Washington, D.C.)."
This value is lower than the MPC introduced by ICRP in 1953 (3700 Bq/m³). I wrote these informations in my paper but  the revisors questionned it. I have only G. Akerblom's paper and I can not verify it.

Jan Skowronek
Central Mining Institute
Plac Gwarkow 1
40-166 Katowice, Poland
e-mail: brxjs@boruta.gig.katowice.pl or brxjs@o2.pl