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REPORT OF THE

UNITED NATIONSSCIENTIFIC COMMITTEE
ON THE
EFFECTS OF ATOMIC RADIATIONGENERAL ASSEMBLY

OFFICIAL RECORDS : TWENTY-FOURTH SESSIONSUPPLEMENT No. 13 (A/7613).

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UNITED NATIONSNew York, 1969

NOTE
Symbols of United Nations documents are composed of capital letters
combined with figures. Mention of such a symbol indicates a reference to aUnited Nations document.

A11nex ELETTER SENT AT THE REQUEST OF THE COM!\llTTEE BY ITS SECRETARY TO STATES I\ffil\I.
BERS OF THE UNITED NATIONS AI''D MEMBERS OF THE SPECL4.LIZED AGEl\'CIES AND OF
THE INTER:\"ATIONAL ATOl\llC ENERGY AGENCY ON 30 APRIL 1968
Sir,
I have the honour to inform you that the ScientificCommittee on the Effects of Atomic Radiation, which
was established by the General Assembly at its tenthsession, has completed its eighteenth session during
which it has reviewed, among other things, the information that it currently requires to assess levels ofradiation resulting from nuclear tests.
The Committee noted that in the past it had received
from a number of countries a large amount of information on radio-active contamination of the environment
from nuclear tests. It expressed its appreciation of
those comprehensive survey data that have greatly
assisted it in its evaluations. Although there are large
areas of Africa, South America and Asia, encompassing
nearly two thirds of the world population, from which
information has been fragmentary, nevertheless theCommittee has been able to make reasonable estimatesof the average e-xposure of the world population.
However, to guard against the possibility that population exposures in certain areas, and therefore theircontribution to world-wide population averages, may
have been underestimated owing to lack of information. the Committee felt that it would be valuable tohave some measurements of bone contamination in a
few selected locations. Extensive surveys in these areas
are not needed for the assessment of the average world
population exposure. but more information on environmental transfer mechanisms would be useful for estimating local exposures in possible future situations ofenvironmental contamination.
For those areas from which most of the information
has come. the general principles governing the transferof radio-active material to man through food chainsare now better understood than when the last request
for measurements was made by the Committee in 1960.
In the past. radio-active contamination has been largely
by direct deposition on the above-ground parts ofplants. but rates of deposition of the radio-active material are now relatively small and, unless large-scaleatmospheric testing is resumed. the future mode of entry of long-lived nuclides into food chains will mainlybe by root absorption of the deposit accumulated in
the soil. Opportunities for quantitative study of thismechanism. as well as of the behaviour of long-lived
radio-nuclides in the soil. have been limited in thepast. and the Committee e-xpressed the hope that surveys would continue in the future to proYide information on this problem.
The Committee considered that this information canbe obtained from surveys conducted in only a limited
number of countries where agricultural practices anddietary composition are representatiYe of those of awider area. and recommended that those countries
which haYe reported sun·ey data on contamination of162

both diet and human tissue since 1961 or earlier continue to do so in the future. The measurements neededby the Committee are, as before, the total amounts ofindividual long-lived nuclides in food and human tissue,levels of external radiation from deposited radionuclides and levels of contamination by short-lived nuclides in food.
The Committee's spec~fic requirements on continuingsurvey measurements are the following:(a) The Committee's estimates of the total amountof individual nuclides in the atmosphere and in soil
have so far been based on the results of two continuing world-wide surveys. The Committee expressed
the hope that the results of these sun'evs would still
be available to it in the future.
·(b) With regard to levels in food. the Committee
requires the results of measurements of Sr&o (inpCi/g Ca and pCi/kg) and Cs137 (in pCi/g K andpCi/kg) contamination in dairy produce, cerealsand vegetables. The Committee also e..xpressed interest in obtaining a few representative measurements of the levels of stable strontiwn in the samefood-stuffs.
(c) Tissue levels include (i) body contents ofCs 137 and (ii) Sr 90/Ca ratios in the skeleton. As
it is anticipated that the distribution of SrD0 in adultbones will become more uniform in the next fewyears. the Committee recommended that intercomparisons of contamination levels in various types ofbone and in v.·hole skeleton be made more regularly
than hitherto. The Committee also noted that anincreasing number of persons were now entering
adult life who had been exposed to Sr90 contamination during their growing years and in whom thedistribution of Sr 00 within the skeleton will be different from those who have only been exposed asadults. The Committee therefore recommended thatthe results obtained from adults should be reported
separately for those between twenty and thirty yearsof age and for those older than thirty in 1967, andthat for the next few vears results for children
should be presented by years of age up to four years
and as a group from five to nineteen years. Becauseof its importance in assessing the long-term behaviourof Sr90 in the human bodv. the Committee would
also be interested in obtaining measurements ofstable strontium in bones of both juveniles andadults from tho<:e populations where comoarable
data for diet are also ;n-ailable.
-(d) Le,·els of e..'i:ternal radiation from depositedradio-nuclides have been recorded continuouslv at
a few sites. and the Committee recommended ·that
these recordings be continued and that other measurements making it possible to impro\'e the accuracylof estimates of external gamma doses from Cs 137
and short-lived nuclides should also be made.
( e) The Committee has a continued interest inlevels of I1 31 in milk and vegetables because of thehigh concentration of iodine in the thyroid gland.
relative to other tissues. and of the resultant local
radiation doses. which can be of particular importance in infants and children.
(f) The Committee is also interested in data onother internal emitters in local areas, when theseemitters make a substantial contribution to radiation
exposure from environmental contamination.

The Committee's requirements on infor111atio11 fromareas not cot·cred b:,1 co11tin1ti11g sur..•eys ctre as follows:
Limited investigations only, rather than continuing surveys, would be adequate for the purpose ofobtaining information from those areas of the worldfrom which data are yet scant. Measurements of Sr90
in bones from selected areas need to be carried out
only once in the near future. The areas of greatest
interest to the Committee are those where the main

163

calcium contribution to the diet is from cereals suchas rice and maize. or from pulses and nuts. The
Committee believes that one effective way of carryingout such a limited collection of samples is by agencies
within the United Nations system and by existing
national laboratories.
The Committee emphasized that it had outlined theinformation at present required for its own purposes
only and noted that its requirements might need afurther revision if massive injections of radio-active
material into the atmosphere through nuclear tests
were to be resumed, and that the requirements would
in any case be revised as soon as sufficient additional
knowledge accumulated.
Accept. Sir. the assurances of my highest consideration.
(Signed) Francesco SELLA

Secretary
United Nations Scientific Committee
011 the Effects of Atomic Radiation

APPENDIX ILIST OF SCIENTIFIC EXPERTS, MEMBERS OF NATIONAL DELEGATIONSThe scientific experts who took part in the preparation of the present
report while attending Committee sessions as men1bers of national delegations
are listed below.
Dr. T. Ishihara
Professor E. Tajima

ARGENTINA

Dr. D. Beninson (Representative)
Dr. A. Placer
Dr. E. Ramos Zabarain
Dr. E. Vander Elst).f.E..XICO

Dr. l\L Martinez-Baez (Representative)
Dr. F. Alba-Andrade
Dr. A. Uon de Garay
Dr. R. Gonzalez Constandse

AUSTRALIA

Mr. D. J. Stevens (Representative)
Dr. R. .Motteram

SWEDEN

Proiessor B. Lindell (Representative)
Dr. L. J. G. Fredriksson
Dr. A. Nelson

BELGIUM

Professor J. A. Cohen (Representative)
BRAZILUNION OF SOVIET SOCIALIST REPUBLICS

Professor L. R. Caldas (Representative)
Professor C. Pavan (Representative)

Professor A. 1\1. Kuzin (Representative)
Mr. G. Apollonov
Professor A. Gus'kova
Dr. I. L. Karol
Dr. A. A. Moiseev

CANADA

Dr. G. C. Butler (Representative)
Dr. J. D. Abbatt
Dr. W. E. Grummitt
Dr. J.B. Sutherland

UNITED ARAB REPUBLICDr. l\L E. A. El-Kharadly (Representative)
Dr. K. E. A. A. l\fahmoud (Representative)

CZECHOSLOVAKIA
UNITED KINGDOM OF GREAT BRITAIN
AND NORTHERN lRELA)JD

Dr. V. Zeleny (Representative)

Dr. E. E. Pochin (Representative)
Mr. K. B. Dawson
Dr. W. G. Marley
Dr. R. S. Russell

FRANCE

Professor L. Bugnard (Representative)
Professor l\L P. Avargues
Dr. A. Benazet
Dr. R. B. Coulon
Professor ]. W. de Grouchy
Dr. M. H. Dousset
Dr. H. P. Jammet
Professor J. Lejeune
Professor P. Pellerin

UKITED STATES OF AMERICA

Dr.RH. Chamberlain (Representath-e)
Dr. A. :M. Brues
Dr. H. D. Bruner
Dr. C. L. Dunham
Dr. E. FurchtgottDr.]. H. Harley
Dr. W. HaymakerDr. D. ]. Kimeldorf
Dr. J. Rivera
Dr. F. Rosenthal
Mr. G. C. Spiegel
Dr. J. G. Terrill
Dr. C. A. Tobias
Dr. P. C. Tompkins

INDIA

Dr. A. R. Gopal-Ayengar (Representati\·e)
JAPAN

Dr. K. Misono (Representative)
Dr. K. Tsukamoto (Representative)
Professor Y. Hiyarna
Dr. R. Ichikawa

164

A.PPE2'DIX IILIST OF SCIENTIFIC EXPERTS WHO HAYE CO-OPERATED WITH THE co:rnmTTEE IN THE
PREPARATION OF THE REPORT
Dr. T. J. Leith

Dr. P. J. Barry
Dr. R. Berger
Dr. K. Edvarson
Professor H.J. Evans
Dr. :E.. I. ICornarovDr.]. Liniecki
Dr. P. C. Kowell
Dr. F. Sella
Dr. A. B. Tsypin
Dr. K. Zakrze,vski

Professor B. Larsson

165

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