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Re: Re[2]: Cs137 in soil and cancer ris
Group,
For additional perspective:
Jean-Michel MURE writes,
> These figures are for external exposure from a contaminated soil only.
> Pathways such as ingestion or inhalation are out of the scope of the initial
> question raised by Mike Baker who is only concerned with external exposure.
> Anyway these Exposure to Dose coefficients are meant to be used to give an
> idea of the dose (pathway=external exposure) that is related to a given
> level of contamination of the soil assuming exposure occurs all time of year.
>
> The figures are for a semi-infinite slab geometry and for exposure at 1 m.
> Soil density is 1600 kg/m3. Exposure is continuous over a year.
>
> The mistake I made is that I forgot to take into account the thickness of
> contaminated soil that Mike assumed to be equal to1 cm.
> The dose conversion factor hence becomes 1.9E-7 Sv/y per Bq/kg. (Ref :
> External Exposure to Radionuclides in air, water and soil, exposure to Dose
> Coefficients for General Application, Based on the 1987 Federal Radiation
> Protection Guidance, ORNL 1993)
> Csoil(Cs137)=0.629 Bq/kg
> ---> EDE=1.19e-7 Sv/y assuming exposure 24h/24h and 365days/365days
> --->letal cancer risk = 6e-9 cancer/y
Worldwide data, UNSCEAR 1993:
Concentration (Bq/kg) Dose rate
(nGy/h) Mean Range Mean
Range K-40 580+-200 12-2190
24 0.5-90 Th-232+ 49+-28 1.5-440
31 0.9-270 U-238+ 40+-34
1.8-520 ( from Ra-226+ ) Ra-226+ 37+-22
2.4-430 17 1.1-200
In Yangjiang County China (Kondo 1993, from Wei 1990:
"The average annual absorbed doses from external gamma rays in the high
background (radiation) area (HBRA) is about 0.21 rad, in the control area (CA)
0.08 rad"
"The HBRA is 540 km^2, 463 villages, and a population of about 80,000."
"The EDE of residents aged 70 in the (HBRA) are 35-53 rem, avg 38 rem.
Therefore, if the life-time dose limit of 35 rem adopted as the intervention
level for evacuation were to be applied, the entire area .. would be evacuated
immediately. Chinese radiation experts have not taken such measures because
they have obtained epidemiological evidence that the natural radiation in this
area is not harmful to residents." From extensive studies from 1970
(retrospective until 1978, prospective since, with individual badging and
medical folllowup: "Cancer mortality is lower in the areas of high background
radiation."
More recent data, including extensive clinical evaluation of thyroid
conditions in women >50 by US thyroid specialists, and other specific studies,
confirm a small statistically significant lower cancer rate in the HBRA. These
populations are highly homogeneous in genetic (all Han peasants) and lifestyle
and geographic conditions, and lived typically >4 generations in their
respective regions.
And from Prof emeritus Zbigniew Jaworowski, Member of UNSCEAR, "..why are
people not evacuated from Norway where all country average lifetime dose is
365 mSv, or high background regions in India with a lifetime dose >2000 mSv,
and in Iran with lifetime dose >3000 mSv? Perhaps in Iran, the gov't chose to
not follow the ICRP guidelines when it considered the fact that in a house in
the city of Ramsar several generations were receiving avg lifetime doses of
17,000 mSv (240 times ICRP exposure limit). Yet these individuals show no
increased incidence of any disease, and some lived to be 110 years of age.
(Sorabi 1990)" [Jaworowski, 1995, "Beneficial Radiation", Nukleonica, 40, 3-11
reporting on the UNSCEAR 1994 report, Appendix B, on Adaptive response. I can
provide a copy of the paper since Nukleonica is a Polish journal of radiation
research to anyone interested, and another by Jaworowski in the June 95 J. of
Regulatory Toxicology and Pharmacology.) Note that the "high background
area" of Norway is significantly higher than the "country average" dose, along
with many other areas in the world.
Clearly, statements of "fear" on going to the Chernobyl area are based on
a political definition of "radiation risk", stated by NCRP and BEIR to be
conservative "for radiation protection purposes" not as predictions of actual
health effects. They are not based on the scientific data of dose effects on
humans, and are contradicted by animal studies and biology. Many in the FSU
and elsewhere decry the massive waste and human suffering caused by the
unjustified application of these conservative "rad protection" principles to
damage real people by forcing unnecessary evacuation in conditions in which no
adverse health effects can be expected to occur. This is part of the reason
why Prof emeritus Dr. Gunnar Walinder, the great radiobiologist and associate
of Rolf Sievert wrote his monograph: "Has Radiation Protection become a Health
Hazard?" and states that this is "the greatest scientific scandal of the
century"!
> Sorry for the initial lack of detail.
>
> Best regards
> JM
>
>
> At 16:05 07/01/1997 -0600, you wrote:
> >
> >_
> >>Dose conversion factor for a contaminated soil assuming Ba137m and Cs137 are
> >in secular equilibirum (which is reasonably acceptable regarding Ba137m
> >half-life (T=4.86E-6 y))
> >= 1.09 E-6 Sv/y per Bq/kg (AECL, 1989) *
> >or = 1.14E-6 Sv/y per Bq/kg (ORNL, 1993)
> >
> >*********
> >How have these dose conversion factors been calculated? Do they take into
> >account ground shine, resuspension, transfer to food and/or water, kids eating
> >dirt etc etc etc... I'm curious as to the applicability of a single "number" to
> >all possible critical groups when the pathways of exposure vary with land use.
> >
> >Regards
> >
> >Alex Zapantis
> >Environmental Radiation Officer
> >Office of the Supervising Scientist
> >40 Blackall Street
>
> >Barton ACT 2600 AUSTRALIA
> >
> >Email: azapantis@mgdestmx01.erin.gov.au
> >Fax : (int+) 61 6 274 1519
> >Phone: (int+) 61 6 274 1642
> >
> >The Office of the Supervising Scientist is a Branch of the
> > Federal Environment Protection Group
> >
> ***************************************************
> Jean-Michel MURE
> ANDRA
> DESS/SBSE
> Parc de la Croix Blanche
> 1-7, rue Jean Monnet
> 92298 CHATENAY MALABRY Cedex
> FRANCE
> ****************************************************
> Tel : (1) 46 11 83 74
> Fax : (1) 46 11 80 13
> ****************************************************
> Email : Jean-Michel.Mure@andra.fr
> ****************************************************
Thanks. I'll provide supporting papers to those interested in biology and data
rather than unfounded "policies" and politics, which are estimated to
cost/waste public wealth worldwide >US $2-million-millions for "environmental
cleanup" (for no public health benefit); and many more $100,000s-millions in
future decommissioning costs. This while destroying the economics and public
acceptance of nuclear and radiation technologies, and human benefits, at
massive economic and environmental cost to the growing populations and food
and energy resource requirements in the world of our children and
grandchildren. These policies make nuclear safety and rad protection "experts"
into destructive overhead, and contributors to management incentives to
eliminate nuclear technologies, instead of valued contributors to the economic
success of nuclear technologies through providing responsible provision for
health and safety of workers and the public. (Note that costs are not in "rad
protection", but rather in the unjustified costs imposed on the organization
for rad releases, worker "protection", waste management, and decommissioning
and cleanup, and associated "regulation", all of which are supported by those
reaping the windfalls, plus those who benefit from eliminating the viability
of nuclear technologies, who never hesitate to use our self-identified
"radiation risks" argument for political and marketing gain).
Regards, Jim Muckerheide
jmuckerheide@delphi.com