Re: Question: Proposals for a Non-LNT world?

[Bernard Cohen <blc+@PITT.EDU>]

Franz Schönhofer wrote:



>One serious question I have to those who want the LNT to be abandoned:

>What is their idea of radiation legislation? Would there be any limits

>now in force regarding maximum permissible doses, MPC's for

>radionuclides in food, air, waste etc. abandoned? Would doctors subject

>their patients to 50 CT's per day? Would consumer products become

>radioactive? Would NPP's be allowed to discharge all their waste in the

>environment? Or would simply all those nice figures multiplied by

>hundred, thousand or one million?

>

>  

>

       ---You are essentially saying that LNT is necessary for 

regulatory purposes. My response to this is the following:



IS LINEAR-NO THRESHOLD THEORY JUSTIFIABLE FOR REGULATORY PURPOSES



            A former ICRP Chairman supports the linear-no threshold 

theory (LNT) because it simplifies bookkeeping. LNT is certainly 

convenient for making health physics calculations. It allows us to 

calculate the risk from any given radiation exposure in quantitative 

terms, which is the goal of any risk analysis. Without LNT, the risk to 

a person from a given dose depends on the concentration of radon in his 

home, his experiences with medical X-rays, etc; effectively, there is a 

synergism between a given exposure and all other radiation exposures. 

Since most of the latter are unregulated, it is impractical to take them 

into account. If we abandon LNT, we largely abandon quantitative risk 

assessment, which might seem to make regulation more difficult.



            But is this really a very serious problem?  It is a problem 

that occurs in nearly every other area of environmental concern. For 

example, LNT is not used for air pollution. There are regulations on 

releases and on ambient levels of SO2, of NOx, of total suspended 

particulates, of fine particulates, of ozone, of lead, etc. For none of 

these can the risk of each additional exposure be calculated 

quantitatively., even if no other pollutants are present.  No 

consideration is given to synergisms between these various pollutants, 

although such synergisms are quite likely to be important.  By the 

standards we apply to radiation, the scientific bases for air pollution 

regulations are mediocre at best.



            But they work quite successfully. They prevent catastrophes 

and generally avoid identifiable deaths. Most importantly, they give the 

public confidence that it is being protected. This confidence is not 

even shaken by studies concluding that tens of thousands of Americans 

die annually from air pollution1. The Media give scant attention to 

these studies, and the public shows little interest as long as no 

victims are identifiably tied to the pollution..



            Is this situation reprehensible? I think not. It allows our 

technology to progress and to increase Society's wealth, and technology 

and wealth create health, far outstripping the harm to health done by 

the pollution. Air pollution reduces our life expectancy by something 

like 30 days2, whereas technology and the wealth it has created have 

increased our life expectancy by 30 years in this century.



            We thought we could do much better with radiation, using LNT 

to calculate risks in quantitative terms. For every little bit of 

radiation, we calculate the number of deaths, and killing is something 

the Media are quick to report. People are moved by such reports and view 

these deaths as real, perhaps even afflicting themselves or their loved 

ones. The public has thus  been driven insane over fear of radiation, 

losing all contact with reality. As a result, we have largely lost the 

benefits of nuclear power which could be averting tens of thousands of 

deaths per year from air pollution (and also solving other environmental 

problems like global warming, acid rain, etc). We are losing many other 

benefits of radiation such as food irradiation which could be averting 

millions of cases of food poisoning, saving thousands of lives, each 

year. We are wasting our Society's wealth on ridiculous clean-up 

programs at nuclear facilities; this wasted wealth could save thousands 

of lives each year if it were spent on biomedical research, on public 

health programs, or on highway safety.



            Our passion for doing much better for radiation than has 

been done for air pollution by using LNT has backfired horribly, costing 

our Society dearly. Perhaps it could be argued that we must be honest 

and scientific at all costs. But is accepting LNT honest science? I have 

reviewed this question in detail in a recent paper3 and concluded that 

it is not. The Health Physics Society Position Paper of January 1996 

concludes that the science does not exist for supporting LNT in the low 

dose region. The situation is the same as for low levels of air 

pollution -- the science just isn't there. The best they can do is 

regulate by assuming a threshold for harm, and that is the best we can 

do for regulating radiation. Far from making regulation of radiation 

more complicated as is often assumed, this would greatly simplify our 

regulatory process



            Thus, there is no honest scientific reason why radiation 

should be treated differently than air pollution in the low dose region  

We should abandon this phony effort to be more scientific in our 

regulatory practices. That way we would be more honest, and we would 

have a much more positive impact on the Society we serve.



 



REFERENCES



1. H. Ozkaynak and J.C. Spengler, Analysis of health effects resulting 

from population exposure to acid precipitation,   Environmental Health 

Perspectives 63:45ff; 1985



 



2. B.L. Cohen, Catalog of risks extended and updated, Health Physics 

61:317-335; 1991



 



3. B.L. Cohen, Validity of the linear-no threshold theory of radiation 

carcinogenesis in the low dose region, Technology 6:43-61; 1999