Tag: Collective dose

Given that the ICRP predicted excess cancers will probably appear in the next10 years, they will not be measurable above the normal rate unless they are rarecancers. Examples are leukaemia in children or thyroid cancer.The ECRR absolute risk method cannot be formally used unless we know theindividual radionuclide exposures. However it can be used if we approximate that 1/3of the dose is internal and that 1/3 of the internal dose carries a weighting of 300(which was the overall weighting factor obtained form the weapons test falloutspectrum of radionuclides epidemiology). Then the annual internal dose is 5.6mSvand 1/3 of this is 1.9mSv which we weight at 300. The total ECRR dose is thus575mSvECRR. The collective dose is then 3,338,900 x 575 x 10

-3

to give 1,919,867person Sieverts and a lifetime (50 year) cancer yield of 191,986 extra cancersassuming the ECRR risk factor of 0.1 per Sievert ECRR. Given the different timeframes, these numbers obtained from the Tondel et al 2004 regression and the ECRRabsolute model based on the atmospheric test cancer yields in Wales and England arein reasonable agreement.The three predictions are given in Table 5

Table 5

. The predicted cancer increases in the 100km zone near the Fukushima site

Model Cancer yield Note, assumptions

ICRP 2838 In 50 years, based on collective doses atexposure of 2

µ

Sv/h for one yearECRR Tondel 103,329 In ten years following the catastrophe, based onsurface contamination onlyECRR absolute 191,986 In 50 years, based on collective doses atexposure of 2

µ

Sv/h for one year; probably halfof these expressed in the first ten years.

Cancer excess in 200km annulus population

The methods employed above may be extended to the 200km annulus if thecontamination levels are known. Presently no data is available of contamination inthese areas although dose rates are available. NOAA Computer modelling carried outby us and published on the internet (www.llrc.org) and elsewhere suggest that theplumes from the catastrophe have travelled south over the highly populated areasshown in Fig4. Dose rates have been published for these areas and from these doserates it can be assumed that significant exposures have occurred. From Table 4 andFig 3 we can assume that the exposures are of the order of 1

µ

Sv/h with associatedcontamination levels. Therefore the methods employed for the 100km area may beextended to the 200km area. The population is, however much greater at 7,874,600.The results