Re: Commenting on EPA FRG 13 (was Commenting on USNRC EISs)

[BobCherry@AOL.COM]

Mike Shaeffer and I collaborated on the Department of Defense comments during the Federal staffing phase of the draft FRG 13. The essence of our non-concurrence was that the FRG 13 did not include errors in the risk coefficients it espoused, thereby implying a greater precision than warranted. 


IMO, the errors in the risk coefficients undoubtedly would depend on dose, dose rate, and who knows what else. I am sure that the risk coefficients would overlap zero (implying possibly no risk or hormesis, take your pick) at low doses and dose rates.


Of course, the EPA apparently disregarded DOD's comment about including errors.


I hope that use of FRG 13's risk coefficients without errors is not a mandate to other Federal agencies. NRC Reg Guide 8.29 uses a risk factor for cancer death of 0.04 per sievert, with no error, but the text states, "...departure from linearity cannot be excluded at low doses below the range of observation. Such departures could be in the direction of either an increased or decreased risk. Moreover, epidemiologic data cannot rigorously exclude the existence of a threshold in the 100-mrem dose range. Thus, the possibility that there may be no risk from exposures comparable to external natural background radiation cannot be ruled out. At such low doses and dose rates, it must be acknowledged that the lower limit of the range of uncertainty in the risk estimates extends to zero." (Hormesis proponents maintain that risk estimates extend to below zero.)


The EPA's risk coefficient of 0.06 per sievert is 50% higher than that in NRC Reg Guide 8.29. Wasn't the risk factor in an old ICRP report about 25 years ago equal to 0.01 per sievert? Is radiation six times riskier than it was in 1975?


Bob Cherry, Ph.D., CHP

Colonel, U.S. Army (retired)


In a message dated 2/26/2003 1:53:00 PM Central Standard Time, mark.hogue@SRS.GOV writes:


> It includes the following note: "c: Latent cancer fatalities are calculated by multiplying dose by the Federal Guidance Report 24 
>
> (FGR) 13 health risk conversion factor of 0.06 fatal cancer per person-Sv (6 × 10-4 fatal cancer per person- 25 
>
> rem) (Eckerman et al. 1999)." 
>
>
> The question is this: Is the process of  calculating deaths in this fashion really a mandate to the NRC? I would think that in light of much discussion to the contrary, that a threshold value should be used. 
>
>
> Please, I am not trying to start a rant on LNT. If anyone can help me research this a bit, I would just like to make a helpful and useful comment to the NRC.