Re: linear hypothesis

[a.zapantis@qut.edu.au (Alex Zapantis)]

>
>And that's the whole point. Radiation protection standards are not
>"scientific." They never have been. 


How do you define scientific? If you mean based on actual experimental
results which are exactly analogous to the situation (ie low doses & dose
rates) in question then you are correct. If you mean based on extrapolation
of data which is not exactly analogous (ie high doses, dose rates) then I
think your statement is a bit harsh.

Unfortunately, as implied in my previous posting, proving or disproving the
linear no threshold model at low doses is near to impossible. However, the
linear model is well established at higher doses, and in the absence of
credible contradictory evidence, I believe that extrapolation of this data
to low doses is defendable AND scientific. 


The ICRP and NCRP have taken the
>most conservative hypothesis possible consistent with using radiation
>and radioactive material at all. There never has been public debate on
>whether such an idea had, or currently has, merit. 


Debate on the model should be constrained to appropriately trained
scientists with access to the best available data, not the general public.
Perhaps I am naive but I consider the ICRP, NCRP, IRPA etc to fit that
description.


All I want to do is
>create reasonable debate. We have had the linear hypothesis forced down
>our throats for more than 50 years. The time has come to question
>whether the hypothesis is appropriate in this day and age recognizing
>what has happened to public opinion about the danger of radiation and
>the consequent gradual, programed demise of the nuclear option.


What does public opinion have to do with testing a scientific hypothesis? It
is OUR responsibility to educate the public and to communicate the merits
and shortcomings of the model. If we allow the results of scientific
endeavour to be influenced by public opinion we are merely politicians.



 If we
>are to loose employment for 4 million in the nuclear industry and an
>annual contribution to the gross domestic product of some 350 billion
>dollars, there better be measurable compensatory benefit. 


I am not familiar with the economics of the nuke industry up there and if
your figures are correct it is a social tragedy. However, once again, it
should not influence the model itself. Rather, more reasonable regulatory
requirements (assuming current requirements are unreasonable) based on the
model and socially acceptable risk should be implemented. Lets face it,
based on the model, the risks associated with micro Sv doses are negligible
and regulatory requirements should reflect this. I'm pleased to say that
here in Queensland Australia, for the most part, they do.


Scientists
>HAVE DICTATED results. They have DICTATED radiation protection standards
>for more than 50 years. And the standards they dictated have been
>corrupted in the public mind. Now, either the scientists should fix the
>corruption or we need different standards. I don't see the scientists
>fixing anything. All they do is make things more complex without ANY
>measurable increase in safety. 

Scientists do not dictate anything. Scientists present hypotheses based on
data. Advisory bodies make general recommendations based on those models and
regulatory agencies dictate what thou shalt do based on those recommendations.

If the standards have been corrupted in the public mind, this is not a
failing of the model, rather it is a reflection of the general radiophobia
exhibited by the public due to poor comunication between the scientists and
the public or the "headlines" philosophy of the popular media. I strongly
disaggree with the suggestion that new standards should be introduced
because the public has a tainted view of the existing ones.


I don't know that 300 rem spread over a
>lifetime will, for sure, cause cancer or anything else.

Either does anyone else. Its a numbers game - probability according to the
model.


 Maybe the Techa
>river data will tell us something. Maybe the Chernobyl data, if it is
>any good, will tell us something. But, until we know radiation at such
>levels over those time frames is, in fact, harmful, I think it is
>unethical and immoral to frighten members of the public into thinking a
>little radiation, no matter how small can and will hurt you.


We do not seek to frighten the public. We seek to educate the public. If
anyone is telling the public that a little radiation "can and WILL hurt you"
that person is acting irresponsibly.


 It is even
>worse for knowledgable individuals to let that idea remain loose in the
>world. If scientists, regulators and other knowledgable people would, in
>a concerted manner, work to eliminate the corruption of the idea that a
>little radiation MAY cause harm into a little radiation WILL cause harm,
>I might be more charitable toward the hypothesis. At this point I don't
>know what else to do except excise the hypothesis.


How can you base your rejection of any hypothesis on the warped
understanding of it which the public may or may not have? If your rejection
was based on studies, data, or even your personal experience, I could
understand that.  If someone showed me a series of credible studies which
shot the linear model down in flames, I would drop it faster than a hot rock.  

Please don't mistake me for one of the "good old boys" who is forever loyal
to the linear model no matter what. (I'm much to young for that) I use and
teach the model, including its shortfalls, because it is the current
generally accepted hypothesis.

PS, its good to see a bit of full on debate on Radsafe!

Regards




                        Alex Zapantis
                        Radiation Safety Officer                               
                        Queensland University of Technology          
                        Health & Safety Section                             
                        Locked Bag No.2
                        Red Hill Qld 4059
                        AUSTRALIA

                        Ph     : 61 7 864 3566
                        fax     : 61 7 864 3993
                        email  : a.zapantis@qut.edu.au