SOURCES, EFFECTS
AND RISKSOF IONIZING RADIATION
United Nations Scientific Committee on the Effectsof Atomic Radiation
1988 Report to the General Assembly, with annexes

UNITED NATIONSNew York, 1988

NOTE
The report of the Committee without its annexes appears as Official Records of theGeneral Assembly, Forty-third Session, Supplement No. 45 (A/43/45).
The designations employed and the presentation of material in this publication d o
not imply the expression of any opinion whatsoever on the part of the Secretariat of theUnited Nations concerning the legal status of any country, territory, city or area. or of its
authorities, or concerning the delimitation of its frontiers o r boundaries.

UNITED NATIONS PUBLICATION
Sales No. E.88.IX.7
ISBN 92-1- 142143-8
09000PANNEX D

Exposures from the Chernobyl accident

CONTENTSParagraphs

INTRODUCTION .......................

1-7

I . T H E ACCIDENT ..................

8-42

A

. The reactor ....................
I . Location ..................
2. Design characteristics .......
3. Cause of the accident ........

B . Radionuclide release and dispersion
1 . Release sequence and composition .....................
2. Atmospheric transport ......
C . Emergency measures ............

Paragraphs

B.

9-22
9-12
13-19
20-22
23-33
23-28
29-33

C

D.

ASSESSMENT ....................

43-99.............

43-61
49-53
54-57
58
59-61

A . Scope and approach
1. Geographic coverage ........
2. Pathways ..................
3. Radionuclides considered ....
4 . Doses evaluated ............

B. Calculational methods for first-yearC.

114-1 16
117-119120
121-123

1 . Iodine-131 in foods ......... 127-130
2 . Caesium- 137 in foods ....... 131.135
The human body ................ 136- 142

IV . FIRST-YEAR DOSE ESTIMATES ...

143-170. Thyroid dose equivalents ......... 145-149. Effective dose equivalents ........ 150-152
C . Pathway contributions ........... 153-155
D . Radionuclide contributions ....... 156-157
E. Transfer relationships ........... 158-170

AB

doses .........................
1 . External irradiation during
cloud passage ..............
2. Inhalation .................
3. External irradiation from
deposited material ..........
(a) During the first month . .
(b) After the first month ....
4 . Ingestion ..................
Calculational methods for projected
doses .........................
1. External irradiation .........
2. Ingestion ..................

1. Transfer from deposition todose from external irradiation
2. Transfer from deposition to
thyroid dose equivalent of
iodine-131 .................
3. Transfer from deposition todose from ingestion ofcaesiurn137 .......................
(a) Transfer from deposition
to diet(b) Transfer from diet to body(c) Transfer from body toeffective dose equivalent159-162
163-164
165-170................ 165-167

111. EVALUATED INPUT DATA .......

100-142

A . Air ...........................

105-113105-107108-1 10I . Radionuclide composition ...
2. Concentrations in air ........

11 1-1 13..................... 114-123. Diet .......................... 124-135

34-42

I1. METHODOLOGY FOR THE DOSE

3. Ratios of integrated concentrations ......................
Deposition
1 . Deposition of caesium-137 ...
2 . Deposition of other radionuclides ...................
3 . Quotient of deposition density
and integrated air concentration .......................
fromexposure
4 . External
deposited materials .........

1

168
169-170

V . DOSE COMMITMENTS ........... 171-184
A Transfer relationships ........... 173- 179
1. Transfer from deposition todose from external irradiation
173.

Paragraphs

Paragraphs

Transfer from deposition todose from ingestion .........
(a) Transfer from deposition
to diet ................
( b ) Transfer from diet to body( c ) Transfer from body toeffective dose equivalent
B. Average dose equiv;rlent commitments in large region\ ...........
C . P a t h ~ a andj radionuclide contributions.. ........................

174- 179
174-175
176
177-179180-181182-184

V1. COLLECTIVE DOSE COMhlIThlENT 185-209.4. Caesium-137deposition with distancefrom Chernobyl ................ 186-188

Inrroducrion

1. The accident in April 1986 at the Chernobyl
nuclear power station in the Union of Soviet Socialist
Republics, in which large amounts of radioactive
materials were released into the environment. was themost serious to have occurred in connection with theuse of nuclear energy t o generate electricity. S\viftemergency response was required, first of all in the
USSR to control and contain the damaged reactor andthen, also, in other countries t o monitor and evaluate
the radiation levels. Because of the attention focusedo n the accident and its aftermath and the large database that was accumulated. the Committee has decided
to assess in derail the population esposures that
resulted from the accident in order to improve thecomparability of results between countries and todevelop further the methodology for dose assessment
from this type of radiation source.

2. The radiation levels from released radionuclides
were highest in the immediate vicinity of the reactor.
The released radioactive materials affected then mainly
the western part of the USSR and the countries ofEurope. Exten~ivenleasurenlents have been made inthese regions, allou.ing the radiation doses t o theaffected populations t o be evaluated in some detail.
Because the released materials became further dispersed throughout the northern hemisphere. estimatesof exposures to populations in other countries h a l ealso been made.
3 . In presenting the results of the assessment. a shortaccount is given of the conditions under tvhich theaccident took place, mainly to convey informationthat will help t o evaluate the radiological impact.
General aspects of the dispersion of the released
radioactive materials are described. The environmental
concentrations and radiation levels encountered aresystematically evaluated and then-applied in a common
methodology for estimating radiation doses.

One of the major uncertainties in this dosimetricassessment is that pertaining t o projected future

4.

Transfer factor for total dose
commitment based on caesium-137
deposition .....................
C . Estimates of collectite effective dose
equivalent commitment ..........
D. Collective dose commitment per unit
release ........................
E. Collective dose commitments fromother radionuclides. .............
B.

2.

V11. SUMMARY .......................

189-194
195-200
20 1-207
208-209110-214
Pages

Tohles .................................

344

References ..............................

370

exposures from the residual radioactive materials in
the environment. Environmental levels and radiation
doses continue to be measured, and the Committee
plans t o use these d a t a t o refine the values of theparameters required for the calculations. It will, forssample, consider further the regional variabilities d u e
to different meteorological o r ecological conditions.
Such analyses would greatly help in refining thetransfer factors and the models used by the C o m mittee in dose assessments.

5 . The Committee has received a great deal ofassistance a n d co-operation from many individuals
and organizations in carrying out this assessment. A
team of experts was formed in the UNSCEAR
Secretariat by staff seconded by the Institute ofBiophysics at the Ministry of Health in Mosco~v.
USSR; by the National Cancer Institute and theDepartment of Energy in the United States: by thehlonitoring a n d Assessment Research Centre in London
and the National Radiological Protection Board in the
United Kingdom; and by the National Committee for
the Research and Development of Nuclear Energy a n d.L\lternatii,e Energies in Italy.
6. Xian! countries submitted scientific data either
directly to the UNSCE.4R Secretariat or to the d a t abank set up in Vienna by the International Atomic
Energy Agency. The UNSCEAR team of experts had
free access to this d a t a bank for the purpose ofderiving data for the assessment. T o obtain additionaldata, the UNSCEAR Secretariat also maintained
frequent and extensitte contacts with experts in various
countries and discussed with them the interpretationand evaluation of results. These contacts were s onumerous that i t would be impossible t o acknowledge
then1 separately. They proved essential to the conductof' the project and they are here collectively recognizedwith appreciation.

7. In approving this Report, the Committee wishes
to acknowledge this help and express its gratitude. It
would also like to draw attention to and commend thespirit of full collaboration and free exchange of dataand ideas between countries, international organizations, laboratories and scientists. which has greatly
enhanced the outcome of this study.

'.

B Y E L O R U S S I A

:

River
Dniepr;,.'I. THE ACCIDENT
8. O n 26 April 1986 at 0123 hours local time an
accident occurred at the fourth unit of the Chernobyl
nuclear power station. The accident destroyed thereactor core and part of the building in which the core
was housed. The radioactive materials released werecarried away in the form of gases and dust particles by
air currents. In this manner. they were widely dispersed over the territory of the Soviet Union. overmany other (mostly European) countries and. in trace
amounts. throughout the northern hemisphere.
A.

THE REACTOR
1. Location

9. The Chernobyl nuclear power station is located in
the Ukrainian Soviet Socialist Republic in the western
USSR, near the boundary with the Byelorussian
Soviet Socialist Republic. It lies about 100 km northwest of Kiev a n d 310 km south-east of .Minsk, o n theRiver Pripyat, which flows into the Dnieper (Figure I).
The nearest boundaries with neighbouring countries.
Poland (eastern part) and Romania (northern part),are 150 km away.

-

KIEV

6

30 km

Figure I. The site of the Chernobyl nuclear power station.

10. The eastern Byelorussian-Ukrainian woodlands
region is characterized by a relatively flat landscape.
with minor slopes down to the river or its tributaries.
The soils of the region are mostly soddy-podzolic,distinguished by low natural fertility. They are. as arule, acid (pH 4.5-5.5) and have a low content ofminerals. The area north of the reactor consists ofabout 50% agricultural land and 50% natural complexes (forests, bogs, water basins). Ploughed land
makes up about half of the agric~ilturalland, with theremainder devoted to natural fodder grasses (cereals
a n d sedge meadows). Dairy and cattle husbandry iswell developed in the region. Potato crops occupy 8%
of rhe territory. T o the south of the reactor. in the
Ukraine. the agricultural use of the land incressrs. andonly 10% of it consists of natural landscapes [I?].
11. The average population density in the region had
been approximately 70 inhabitants per km2 up t o thestart of construction work on the Chernobyl power
plant. At the beginning of 1986, the total population
within an area of 30 km radius around the power
plant was approximately 100,000; of this total, 49.000
lived in the town of Pripyat, situated to the west of theplant's 3-km safety zone, and 12,500 in the town ofChernobyl, the regional centre, about 15 km to thesouth-east of the plant.
12. The construction of the Chernobyl nuclear power
station was carried out in three stages; each comprised
two 1,000-MW reactor units. The first stage (Units 1
a n d 2) was constructed between 1970 and 1977 andthe second (Units 3 and 4) was completed in late 1983.
In 198 1, work was started on two more units of thesame type at a site 1.5 km to the south-east of theexisting site [I I].
2.

Design characteristics

13. The reactors of the Chernobyl nuclear power
station are graphite-moderated, light-water-cooledsystems knorvn as RBMK-1000. The installed electricalgenerating capacity of each unit is 1,000 M W. Eachpair of reactors at the station shares a turbine
generator room that houses four turbine generatorsand their associated multiple forced circulation systems.
The reactor pairs are located in separate blocks
adjoining the central service unit.

13. The core matrix of the RBMK-1000 reactor
consists of graphite blocks (250 mm X 250 mm. 600 mmhigh) stacked together t o form a cylindrical configuration 12 m in diameter and 7 m high. It is located in aleak-tight cavity formed by a cylindrical shroud, thebottom support structure and the upper steel cover.
Apart from the solid graphite blocks forming theradial reflector, each block has a central hole providing
the space for the fuel channels or absorber rod
channels. There are 1.661 individual vertical fuelchannels. Fuel and control rod channels penetrate thelower and upper steel structures and are connected to3.

two separate cooling systems, below and above thecore.
15. The fuel. in the form of U 0 2 pellets. is sheathedin a zirconium-niobium alloy. Eighteen fuel pins.
approximately 3.5 m long, are arranged in a cylindricalcluster; two of these clusters f i t on top of each otherinto each fuel channel. Fucl replacement is done onpower by a fuelling machine located above the core.
One or two fuel channels can bc refuelled each day.
16. The coolant system consists of two loops. The
coolant enters the fuel channels from the bottom at
270cC. heats as i t moves upward, and partially
evaporates. The mass steam content at the core outlet
is approximately 14.5% at full-power operation. The
outlet pressure and temperature are 7 MPa (70 bars)
and 284°C. The wet steam of each channel is fed to
steam drums. of which there are two for each coolingloop. The dry steam from the drums is fed into one oftwo 3.000 rpm 500-MW(e) turbine generators. The
circulation pumps supply the coolant to headers,which distribute it to the individual fuel channels of
the core. In each loop. four pumps are provided, oneof which is normally on stand-by during full-power
operation. The coolant flow of each fuel channel canbe independently regulated by an individual valve tocompensate for variations in the power distribution.
The flow rate through thc core is controlled by feedpumps [I I].
17. Approximately 95'70 of the energy from thefission reaction is transferred directly to the coolant.
The remaining 5% is absorbed within the graphite
moderator and mostly transferred to the coolant
channels by conduction. which leads to a maximum
temperature within the graphite of approximately
700°C. A mixture of helium and nitrogen gases
enhances the gap conductance between the graphite
blocks and provides chemical control of the graphite
and pressure tubes.
18. The Chcrnobyl Unit 4 reactor had the following
principal specifications [I 11:
Thermal power
Fuel enrichment
Mass of uranium in fuel assembly
Fuel burn-up
Maximum design channel power
Isotopic composition of unloaded fuel
U-235
U-236
Pu-239Pu-240Pu-241
19. At equilibrium fuel irradiation, the reactor has aposirive void reactivity coefficient. However, the fueltemperature coefficient is negative and the net effectof a power change depends on the power level. Under
normal operating conditions, the power coefficient isnegative at full power and becomes positive below
approximately 20% of full power. The operation of
the reactor below 700 MW(th) is therefore restrictedby normal operating procedures. The radionuclide
composition of the Chernobyl Unit 4 core is shown in
Table 1.

Cause of the accident

20. The accident happened while a test was being
carried out on a turbine generator during a normal,scheduled shutdown of the Unit 4 rcactor. The test
was intended to ascertain the ability of a turbine
generator, during station blackout, to supply electricalenergy for a short period until the stand-by diesel
generators could supply emergency power. Written test
procedures that were unsatisfactory from the safety
point of view, and serious violations of basic operating
rules put the reactor at low-power [200 XIW(th)]operation in coolant flow rate and cooling conditions
that could not be stabilized by manual control. In
view of the design features already mentioned (thepositive power coefficient at low power levels), thereactor was being operated in an unsafe regime. At thesame lime. the operators, deliberately and in violationof rules, withdrew most control rods from the coreand switched off some important safety systems [I I].
21. The subsequent events led to the generation of
an increasing number of steam voids in the reactor
core, which enhanced the positive reactivity. The
beginning of an increasingly rapid rise in power was
detected, and a manual attempt was made to stop thechain reaction (the automatic trip, which the test
would have triggered earlier, had been blocked).
However, there was little possibility of rapidly shutting
down the reactor as almost all the control rods had
been completely withdrawn from the core. The continuous reactivity addition by void formation led to aprompt critical excursion. It was calculated that thefirst power peak reached 100 times the nominal power
within four seconds [I I]. Energy released in the fuel by
the power excursion suddenly ruptured part of the fuelinto minute pieces. Small, hot fuel particles (possibly
also evaporated fuel) caused a steam explosion.
22. The energy released shifted the 1,000-tonne coverplate of the reactor, cutting all the cooling channels on
both sides of the reactor cover. After two or threeseconds. another explosion occurred, and hot pieces of
the reactor were ejected from the damaged reactor
building. The damage to the reactor permitted theinflux of air, which then caused the graphite to burn.

B.

RADIONUCLIDE RELEASEA N D DISPERSION

1. Release sequence and composition
23. Damage to the reactor containment and core
structures led to the release of large amounts ofradioactive materials from the plant. The release did
not occur in a single massive event. On the contrary,
only 25% of the materials released escaped during thefirst day of the accident; the rest escaped over a nineday period. The estimated percentages of various
radionuclides released from the total in the inventory
are shown in Table 1. Soviet experts were able toreconstruct the overall release process, as shown in thetime-dependent release-rate curve in Figure 11.

special measures taken, which caused the fission
products to be included in compounds that werechemically more stable.

Sharp drop

-3

I

I
r -1
r - i II
I I

I-> 400 - 350 450

v

n.
m

Heat-up p e r i o dY= 300 -

4
C

"7
W

5
2

w

-1

I
I

l

4I
I

150

100
50
0

-

I

-

I
,
J

1

Z

I----

-----

-J

---------

3

4

S

b

.

I

I

--1
- - 1 ----I

I
I

+

l

r- I
Cool-down p e r i o d-----II--4
200 F 1
I 1
250

--- 3
0

m
U
n

'f

(U

I
7

8

9

l

O

25. On the basis of radiation measurements a n d
a n a l y e s of samples taken within a 30 km radius o f theplant and throughout the USSR. it ivas estimated thatmaterials with activity in the range of 1-2 EBq h a dbeen released from the fuel during the accident. .4n
error range of 50% has been quoted. These figures
d o not include the release of the noble gases xenon
and krypton. which are thought to have been released
completely from the fuel. About 10-20% of the volatile
radionuclides iodine, caesium and tellurium and 3-65,
of other more stable radionuclides. such a s barium.
strontium, plutonium, cerium etc., were estimatedto have been released (Table 1). The estimate of the
I3'Cs release is compared in section V1.D with theamount calculated from estimated deposition in thenorthern hemisphere. The agreement is reasonable,considering the wide uncertainties associated with both
estimates.

M

DAYS AFTER INITIATIO1i OF ACCICENT ON 26 APRIL

Figure il. Daily release rate to the atmosphere of radioactive
materials, excluding noble gases, during the Chernobyl accident.
The values are decay-corrected to 6 May 1986 and have arange ol uncertainty of + 50%. [ I l l

24. The release-rate curve may be subdivided into fourstages:( a ) The initial release on the first day of the accident.
During thls stage, the niechanical discharge ofradioactive materials was the result of the
explosion in the reactor;(b) A period of five days during which the release
rate declined to a minimum approximately six
times lower than the initial release rate. In thisstage, the release rate decreased owing to themeasures taken to fight the graphite fire. These
measures. which consisted of dropping about
5,000 tonnes of boron carbide, dolomite, clay andlead on to the core from helicopters, led to thefiltration of the radioactive substances released
from the core. At this stage, finely dispersed fuel- escaped from the reactor directly with a flow of
hot air and with the fumes from the burning of
the graphite.
(c) A period of four days during which the release
rate increased again to about 70%) of the initial
release rate. Initially, an escape of volatilecomponents, especially iodine. was observed;
subsequently, the composition of theradionuclides resembled that in spent fuel. Thesephenomena were attributed to heating of the fuelin the core to above 2000°C, owing to residual
heat release.
(d) A sudden drop in the release rate nine days after
the accident to less than 1% of the initial rate anda continuing decline in the release rate thereafter.
This final stage, starting on 6 May, was characterized by a rapid decrease in the escape of fission
products and a gradual termination of discharges.
These phenomena were the consequence of the

26. Only two earlier reactor accidents caused significant releases of radionuclides: the one at Windscale(United Kingdom) in October 1957 and the other atThree Mile Island (United States) in March 1979 [U I].
While it is very difficult to estimate the fraction of theWindscale radionuclide core inventory that was released
to the atmosphere. it has been estimated that that
accident released twice the amount of noble gases thatwas released at Chernobyl. but 2,000 times less "'1
and "'Cs [D5]. The Three Mile Island accident
released approximately 2% as much noble gases a n d0.00002% as much IJ1Ias the Chernobyl accident.
27. From the c o m ~ o s i t i o n of air s a m ~ l c s taken
during the Chernobyl release and the total release-rate
data. tentative isotopic release rales for individual
radionuclides were constructed [ I l l . These generally
follow the pattern of the total release rate (I;igure 11).
with decreasing release rates initially and increasing
rates until the end of the release period. .Additional
information has been presented [I31 that showschanging isotopic ratios during the release period(Table 2): for example, variable '"1 relative to "'Cs ininitial emissions and higher Io3Ru. Io6Ru, I4'Ce and"'Ce in later emissions. The changing physical conditions and. possibly, the involvement of fuel of varying
burn-up may explain these features. The chemical formof the materials released as aerosols was auite
variable. The particle size of aerosols ranged from lessthan 1 micrometre to tens of micrometres.
28. For the region around the Chernobyl site detailed
maps of radionuclide deposition could be drawn in1986 and 1987 based on measurements of external
dose rates and analyses of environmental samples [A9,1121. The pattern of deposition within other regions of
the Soviet Union was also established through gamma
dose-rate measurements from aircraft and analyses of
the radionuclide content of soil samples taken at alimited number of locations. These procedures enabled
a n estimate to be made of the total amounts ofradionuclides deposited in the Soviet Union. Thisestimate was used in deriving the total amount ofradionuclides released, as mentioned before. The
proportions of the core inventory deposited at various
distances from Chernobyl were estimated to be as
follows p 11:
On-site:0.3-0.59t
0-20 km:
1.5-296
Beyond 20 km:
I-1.5%

2. Atmospheric transport
29. At the time of the accident, surface winds at the
Chernobyl site were very weak and variable indirection. However, at 1,500 n~altitude the winds were
8-10 m/s from the south-east. The initial explosions
a n d heat from the fire carried some of the radioactive
materials to this height, where they were transportedby the stream flow along the western parts of the
USSR toward Finland and Sweden. The arrival ofradioactive materials outside the USSR was first noted
in Sweden on 27 April [Dl]. The transit time of
36 hours over a distance of some 1.200 km indicatestransfer at an average wind speed of 10 m/s.

30. According t o aircraft measurements within the
USSR. the plume height exceeded 1.200 m on 27 April,\vith the maximum radiation occurring at 600 rn [I4].
On subsequent days, the plume height did not exceed
200-400 m. The volatile elements iodine and caesium,
were detectable at greater altitudes (6-9 km), withtraces also in the lower stratosphere [Jl]. The refractory elements, such as cerium. zirconium, neptuniumand strontium, were for the most part of significanceonly in local deposition within the USSR [13. 141.

3 1. Changing meteorological conditions, with winds ofdifferent directions at various altitudes, and continuing
releases over a 10-day period resulted in a very
complex dispersion pattern. The plumes of contaminated air that spread over Europe are described in ahighly simplified manner in Figure 111, along with thereported initial arrival times of radioactive material.
37. The initial plume, depicted as A in Figure 111.
arrived on 27 April in Sweden and Finland. A portionof'this plume at lower altitude was directed southward
to Poland and the German Democratic Republic.
Other eastern and central European countries became

Flgure Ill. Descrlpllve plume behavlour and reported lnltlal arrlval llmer of detectable actlvlv in alr.
Plumes A, 8. and C correspond to air mass movements orlglnating from Chernobyi on 26 Aprll.
27-28 Aprll, and 29-30 Aprll, rerpecllvely. The numbers 1 lo 8 lndlcate lnltlal anlval tlmes: 1 (26 Aprll).
2 (27 April), 3 (28 April), 4 (29 April), 5 (30 Aprll), 6 (1 May), 7 (2 May), 8 (3 May).

affected on 29 and 30 April (plume B). Activity in air
entered north-east Italy during 30 April (also plume B).
Central and southern Italy first had evidence of theplume's arrival during the following day. Switzerland
reported its first arrival on 30 April. The generally
northward flow air across western Europe brought
detectable activity to eastern France, Belgium and theNetherlands on 1 May and to the United Kingdom on
2 May. Contaminated air (plume C) arrived in Greece
on 2 May in the north and on 3 May in the south[GZ]. Airborne activity was also reported in Israel.
Kuwait and Turkey in early May [K 1. S6. TI].
33. Long-range atmospheric transport spread thereleased activity throughout the northern hemisphere.
Reported initial arrival times were 2 May in Japan.
4 May in China, 5 May in India, and 5-6 May in
Canada and the United States [B 1, C7, L2, L6. N4].
The simultaneous arrival at both western and easternsites in Canada and the United States suggests a largescale vertical and horizontal mixing over wide areas[L2. R8]. No airborne activity from Chernobyl has
been reported in the southern hemisphere.

radiological monitoring. Provisions were made fordecontaminating people's skin and, in some cases, forchanging their clothing.
37. In view of the duration of the release of radioactive gases and aerosols from the damaged reactor, it
was decided that the accident zone should be further
evacuated. As a result of this decision, over 88.000
people, including 21,000 children, were evacuatedfrom the Kiev region and a further 25,000 people.
including 6,000 children, were evacuated from theGomel region of Byelorussia. After the radiation
situation had been verified, about 1.000 people were
evacuated from the Zhitomir.region in the Ukraine
and a similar number from the Bryansk region in the
RSFSR. The total number of evacuees rose to 1 15.000.
All of these people were medically examined andresettled in neighbouring districts [A9, 1121.

C. EMERGENCY MEASURES

38. To prevent the iodine radioisotopes (mostly "'I)
present in the plume from accumulating in the
thyroid. potassium iodide preparations weredistributed
to the population in the surrounding zone starting on
the morning of 26 April. During the following days.
iodine prophylactics were given to 5.4 million people
in the USSR. including 1.7 million children [I 12. 1161.

34. After the accident, the first emergency measurestaken at the nuclear station were fire-fighting andshort-term operations to stabilize the reactor. During
the night of 25-26 April 1986, 176 reactor operational
staff and workers from different departments andmaintenance services were on duty at stages one andtwo (Units 1-4) of the nuclear power station. In
addition. 268 builders and assemblers were at work on
the night shift at the construction site of the third
stage.

39. Some tens of thousands of cattle also had to be
removed from the contaminated area. Measures weretaken to prevent or reduce the contamination of water
bodies and ground-water supplies. The extensive
environmental radiological monitoring that took placefrom the very beginning revealed many foodstuffs had
been contaminated. On the basis of derived intervention levels for the most important items in the diet. theconsumption of locally produced milk and otherfoodstuffs was banned over a considerable area [I 121.

35. Of the on-site personnel and fire-fighters, about

40. According to measured levels of contamination,
the area within a 30-km radius of the reactor was
divided into three zones: (a) a zone of some 4-5 km
around the plant, where no re-entry of the general
population is foreseeable in the near future and where
no operations other than those required at the
installation will be permitted: (b) a 5-10 km zone.
where partial re-entry and special operations may beallowed after some time; and (c) a 10-30 km zone.
where the population may eventually be allowed to reenter and agricultural activities may be resumed.
subject to strict radiological surveillance. Personnel
and vehicles are being controlled at the zone boundaries
to reduce the spread of contamination.

300 had to be hospitalized for burns and the diagnosisof possible radiation injuries. These individuals wereobserved and given care and, if necessary, specialized
treatment. The short-term effects and treatment ofradiation injuries caused by the accident arc discussed
in the Appendix to Annex G . "Early effects in man ofhigh doses of radiation".
36. A system of meteorological and radiologicalmonitoring was organized to survey the contaminationlevels in the surrounding area. Aerial radiologicalmonitoring was carried out by aircraft and helicopters
equipped with air samplers and radiation-detection
instruments. On the morning of 26 April, people in
the town of Pripyat were instructed to remain indoors
and to keep their windows and doors shut. Schools
and kindergartens were closed. Late at night on
26 April, radiation levels in Pripyat started rising,reaching about 10 mSv/h on 27 April. I t soon became
apparent that both the lower intervention level for
evacuation (250 mSv whole-body dose) and eventuallyeven the upper intervention level (750 mSv wholebody dose) could be exceeded if the population
remained in their homes and no other countermeasures
were taken. The evacuation of Pripyat started on themorning of 27 April. after safe evacuation routes had
been established on the basis of the first results of

41. Great effort has been devoted to decontaminating
off-site areas. In a 7,000 km2 area surrounding thereactor, houses and, particularly. public buildings(schools, nurseries, etc.) were repeatedly treated.
Houses that could not be brought to acceptable levels
and contaminated, old buildings of low value were dismantled and buried. Roads and other contaminatedsurfaces were covered with asphalt, gravel, broken
stone, sand or clean soil, which brought about 10- to
100-fold decreases in gamma dose rates. In contaminated agricultural areas, deeper ploughing was carriedout and more mineral fertilizers were added. Grasslands and pastures were also ploughed and reseeded.

All of these measures substantially reduced radionuclide transfers and radiation levels.
42. In many countries the countermeasures taken
immediately after the accident were effective in reducing
individual and collective doses. Thyroid dose equivalents were reduced by 80-9092 in the most contaminated region of the USSR. Estimates of theeffectivenessof the I3'Cs countermeasures in that country varied
between 20'% and 90%. depending on the level ofcontamination. In Austria, the Federal Republic of
Germany and Norway, doses were reduced between
30% and 50% by countermeasures, and in other
European countries they were reduced somewhat less[N5]. These countermeasures were taken into accountin the Committee's assessment, as far as possible, byconsidering the reduction in intakes of contaminatedfoods.

11.

METHODOLOCJ' FOR THE DOSEASSESSMENT
A. SCOPE A N D APPROACH

Since the accident, a sufTicient number of measurements have been made t o show the basic features toconsider in a dosimetric evaluation. The main pathways
a n d radionuclides contributing to doses are external
irradiation from deposited radioactive materials (primarily 13'Cs in the longer term) and the dietaryingestion of radionuclides ("'1 in milk and leafy
vegetables during the first month and, after that. lJ4Cs
and I3'Cs in foods).
43.

The inhomogeneous deposition of dispersedmaterials makes i t necessary to take a regional
approach to dose calculation. Enough information isavailable to calculate doses in the most affected
region. which includes most of the European countries(some of these countries were further subdivided). The
input values for the calculations make full use ofmeasurement results through the first year following
the accident. Thereafter. projections are required toestimate future environmental behawour. primarily of"7Cs. and the continued contribution to dose for a
few decades, These projections were made on the basisof long-term observations of global fallout from
nuclear weapons testing.

(local fallout) was largely ignored; its distribution wasvery uneven and its contributions to the total collective dose commitments were small, and (b) following
releases from nuclear installations, environmental
concentrations and body burdens are often below thedetection limits of the measuring instruments. Doses
are calculated using generic source terms characteristicof the particular type of nuclear installation underconsidcrntion and using environmental transfer models.
the parameter values of which are largely independentof the location of the installation.
In the case of the accident at Chernobyl. a
different set of conditions prevailed: ( a ) the release
was into the troposphere and took place from a single
location at a specific time of year; ( b ) even so. theduration of the release over several days, the large sizeof the affected region and changing weather throughout the region resulted in a locally varying deposition
pattern; (c) the accident occurred a t different stages in
the agricultural growing season: in the north ofEurope, the season had not yet begun. in the south it
was already under way; (d) protective measures varied
from country to country; (e) a large number ofenvironn~ental measurements were made available,
providing input data for comprehensive dose assessments.

46.

In these circumstances. UNSCEAR was able toperform its dose assessment for the Chernobyl accident
in some detail, accounting for regional variabilities but
applying uniform calculational methods to achieve
comparability of results between countries. The Committee relied as much as possible on measured results
and used a general model to project the dose
commitment.
47.

34.

It may be instructive to consider the differences
between this dose assessment and the previous
UNSCEAR dose assessments carried out in connection with nuclear fallout or routine. low-level releases
from nuclear fuel-cycle installations; namely. that(a) much of the radioactive debris from nuclear
weapons tests in the atmosphere was injected into thestratosphere, from which altitude there was rather
more uniform hemispheric deposition over the course of
several years. Doses could be assessed o n the basis of alatitudinal deposition distribution derived from a
relatively small number of measurements and on thebasis of transfer factors inferred from measurements inonly a few countries. Representative rather than comprehensive results were required. Short-term deposition
45.

This report includes estimates of average doses topopulations of countries. Occupational exposures arc
not included. because dose information for workers
participating in the restoration work in the USSR is not
yet available.

48.

1.

Geographic coverage

There are practical reasons for considering countries as the basic geographic units: most measurements
have been co-ordinated and averaged country bycountry and much of the secondary data, such as
population, food production and consumption. isavailable only o n a similar basis. This approach also
allows the Committee to compare its calculations offirst-year dose equivalents with the calculations of theindividual countries. Dose commitments are thencalculated o n a regional basis.
49.

50. Although it was the countries of Europe thatwere most affected by the Chernobyl accident. theradioactive materials became dispersed throughout thenorthern hemisphere, and so the dose assessment
considers the entire hemisphere. It is well establishedthat, for an atmospheric release into the lower
troposphere. there is very little transfer of particles
from one hemisphere to another. Although there may
be some transfer of dose to southern hemisphereresidents through imported foods, this increment in
the collective dose equivalent can be accounted for byconsidering total production as well as consumptionof foods in the affected regions.
51. Because they were closest to the release point.
the countries of northern. eastern and western Europe
and the western part of the USSR require the mostdetailed consideration. It was in these places that
deposition u a s greatest and most non-uniform. In
countries further removed from the release point. themore widely dispersed material was deposited withmore regional uniformity and was, at any rate. lesssignificant from a dosimetric standpoint.
52. For almost all the countries of eastern andwestern Europe, enough radiation-monitoring dataand other information were available to allow detailed
dose calculations for the first year. In so far as was
possible, each country was considered as a single
geographic unit. However, to avoid averaging wideranging dosimetric data, several countries were subdivided. These geographical breakdowns within thevarious countries of Europe are indicated in Figure IV.
For the calculation of dose equivalent commitments.
countries were combined into broad geographicalregions.

53. In Asia and North America. only IOU, levels ofradioactivity could be detected. The approximate dose
estimates for some countries in these regions havebeen extrapolated to obtain estimates for larger
geographic areas. Although they were not significantly
affected by the airborne transport of radioactive
materials from the accident. other developing countries have been concerned about the possible contarnination of imported foods. Further. the accident has
prompted several countries to engage in activities toevaluate and assess immediate and late effecrs of thisand other possible accidents. I t is clear that international agencies must become involved in the trainingof scientists and technicians: the procurement ofequipment; the development of simplified techniques
for measurement and assessment; and procedures on
which to base setting of restrictions on imports ofcontaminated foods.

There are two primary pathways t o be consideredin thts dose assessment: (a) external irradiation fromradioactive materials deposited on the ground and(b) ingestion of contaminated foodstuffs. T w osecondary pathways have been considered as well,54.

Figure IV. Divislon of Europe by country, or by subregions within counlrles, for purpose of the dose assessment.

since the concentrations of radionuclides in air, on
which they depend, have been generally available:(a) external irradiation from radioactive materials
present in the cloud. referred to as "cloud gamma".
a n d (b) inhalation of radionuclides during passage ofthe cloud. The inhalation pathway can. in fact. beimportant right after an accident and if people are subsequently evacuated and received no further exposure. it
can turn out to have been the most important
pathway.

55. Some data available from different countries
show a small amount of resuspension of the depositedmaterial that led to measurable concentrations in air
some weeks or months after the accident. The
contribution of resuspension to further inhalation
doses is considered to be s n ~ a l lin comparison to thatof the other exposure pathways.
56. The path\va!.s of cloud-gamma exposure andinhalation of radionuclides are effective only for the
short period before the airborne material has been
deposited. Transfers along the two primary pathways
continue for a length of time that depends on the halflives of the radionuclides, some tens of days for "'1.
for example, and some tens of years for "'Cs.
57. For the ingestion pathivay, only the basic fooditems have been considered: milk products, grain
products, leafy vegetables, other vegetables and fruit,
a n d meat. Those five categories are sufficient toaccount for the food ingeslion of most individuals.
Radionuclide uptakes in other foods, such as mushrooms and lake fish, have been noted. Although theseother foods may be irnportant for some consumers,
they, like other possible, but minor, pathways, havelittle effect on collective dose estimates.

3.

Radionuclides considered

58. Only "'I. '"Cs and "-Cs. the most important
contributors to the total dose. have been consideredsysten~aticallyby the tarious countries. Other radionuclides ("Zr, I0'Ru. ;"bRu. ."re. '"OBa and .'Ice)
were reported in air or deposition. Several of the latter
were important short-term contributors to cvternal
irradiation from deposited material; when not measured
directly, they may be accounted for by scaling to 13-Cso r "I1 deposition. The long-lived radionuclidss 'H,"C. 85Kr and "'1 are discussed later. They. too. are
but minor contributors to the total dose.

4.

Doses evaluated

59. The assessment of doses has two components:(a) the committed dose equivalents resulting fromexposures and intakes during the first year following
the accident and (b) the collecti\,e effective dose
equivalent commitment due to the accident. In assessedcountries and subregions, estimates are made of thefirst-year effective dose equivalent, i.e. the dose
received in the first year from external irradiation andthe dose committed from first-year inhalation andingestion of radioactive materials. First-year dose
equivalents to the thyroid of adults and one-year-old
infants are also estimated.
60. The evaluations of dose for the first year reflect
as nearly as possible the prevailing conditions, taking
into account not only measured values but also
shielding and occupancy factors and protective measures. The recently observed and reported reduction in
exposure levels in urban areas as a result of runoff has
been incorporated into the dose models. Other factors
are introduced and described along with the calculational methods.

The second component of the dobe assessment is
the collective effective dose equivalent commitment.
which requires projection of doses to be received in
the future from deposited materials. For this purposethe models developed by the Committee for estimatingdose commitments from fallout have been used.
Because the parameters for these niodels were obtainedby averaging results from widely separated regions.
wider groupings of countries have been selected toreflect regional deposition patterns. The dose commitments have been evaluated for each large region
and used for calculating the collective dose commitment. The estimates are based on both consumption
and production of foods.
61.

B.

CALCULATIONAL hiETHODSFOR FIRST-YEAR DOSES

For the most part, the calculations simply
involve multiplying integrated concentrations by dose
factors, with reduction factors taken into account. The
integrated concenlrations in food are derived, where
possible, from measurements through the first year
follo\ving the accident. T o supply missing data, use ismade of ratios to other measurements or to "default"
values, tvhich are values derived from measurements
at other sites o r averaged from representative resultsfrom neighbouring locations. The methods for eachpathway are described below.
61.

1.

Exterrlal irradiation during cloud passage

63. During a very brief period, usually only hours
but sometimes a few days. the passing cloud ofcontaminated air exposes people to external irradiation. This exposure is referred to as cloud-gamma
irradiation. .Although this exposure rate could intheory be measured direaly. -in practice it is notpossible to distinguish this component from radiation
caused by deposited activity on the ground. The doses
from cloud-gamma exposure can be easily calculated
from measured air concentrations. Thc equation forradionuclide i is

FIE.Ji) = C 3 i ) Oc(i) ( I - Fo)+ C:(i)aC(i) Fo Fs

where FIE.c ( i ) is the cloud-gamma effective dose
equivalent (Sv): C:(i) is the integrated concentrationin outdoor air (Bq d/m3); a, (i) is the effective dose
equivalent factor per unit integrated air concentration

(Sv per Bq d/m3); F, is the indoor occupancy factor(the fractional time spent indoors); and F, is thebuilding shielding factor (the ratio of indoor to
outdoor dose rates).
64. The first term in the equation is the outdoor
component of effective dose equivalent and the second
term is the indoor component. An additional small
component of dose from contaminated air indoors has
been neglected in this calculation. The effective dose
equivalent factors have been derived for uniform semiinfinite cloud geometry. A list of effective dose
equivalent factors is given in Table 3. The same values
are assumed to apply to both infants and adults.

65. F o r the calculations here. an indoor occupant).
factor of 0.8 and a building shielding factor of 0.2
have been used for all countries. The values of thesefactors had been previously used by the Committee[UI. U2]. I t is to be noted, however. that measurements a s well as calculations of the shielding factor
afforded by buildings show a large range of variation
depending on the kind of building: from 0.01 to 0.1
for multi-storey buildings and from 0.1 to 0.7 forsingle-family houses in Sweden [C25], while in Norway the mean shielding factor of houses \itas reported
a s 0.5 during the first month and 0.29 during the sixth
month following the accident [S14]. For typical
European houses, calculations for "'Cs deposition
yield values of 0.44. 0.084, and 0.0063 for the groundfloors of prefabricated. semi-detached. and multistorey houses, respectively [M8].
66. T o calculate cloud-gamma (and also inhalation)
doses, it is necessary to knot\ the integrated concentrations in air of many short-lived radionuclides. In somecountries, complete data were available. In others,
only one or a few radionuclides were reported. soconcentrations of other radionuclides were inferredfrom ratios measured in nearby countries. In a few
cases, n o measured air concentrations were available.
s o the integrated air concentration of I3'Cs wasinferred from its ground-deposition density and anominal quotient of ground deposition to integrated
air concentration of 1,000 m/d: the integrated concentrations of other radionuclides were then inferredfrom ratios to "'Cs measured at nearby locations.

2.

Inhalation

67. Contaminated air is inhaled during the shorttime that the radioactive materials remain airborne.
This is a straightforward calculation from measured
integrated concentrations in air. The equation forradionuclide i is:where H,,,(i) is the inhalation effective dose equivalent(Sv); C:(i) is the integrated concentration in outdoor air(Bq d/m3); B is the breathing rate (m3/d); @,(i) is thedose per unit intake from inhalation (Sv/Bq): F, is theindoor occupancy factor; and F, is the indoor air
concentration reduction factor (the ratio of indoor to
outdoor air concentrations).

68. The first term is the outdoor component and thesecond term is the indoor component. The breathing
rates are taken to be 22 m3/d for adults and 3.8 m3/d
for infants [I6]. Indoor occupancy is the same as in theprevious calculation. Air concentrations are assumed
to be lower indoors due to filtration effects. For all
countries, the value of the indoor air concentration
reduction factor is taken to be 0.3. Experiments in
Finland and Norway showed a range of values. from
0.22 to 0.47, for this factor [C23]: in Denmark theyranged from 0.1 to 0.5 [R9]. Calculations have been
made both for the thyroid and for the effective dose
equivalents. This calculation also depends upon dataof integrated concentration in air with "'I being ofparticular importance. Such data were inferred where
needed as discussed under the section above. Doseequivalent factors are listed in Table 4.

3.

External irradiation from deposited material

69. External irradiation from radioactive materials
deposited on the ground makes a significant contribution to the total dose equivalent. During the firstmonth after deposition. a number of short-lived
emitters. including "ZTe. ":I. !''I, "OBa. I4OLa and'3bCs. were important components of the total external
gamma exposure rate. For several months, ""Ru a n d
IohRu made contributions, but since then only "'Csand ]"Cs have been of significance. External gamma
esposure rates will remain elevated for some years due
to '"Cs and for some tens of years due to "'Cs.
70. Calculation of the effective dose equivalent fromexternal irradiation from deposited material proceeds
in two steps: the exposure in the first month isconsidered separately from exposure in subsequentmonths.
(u)

During rhcfirsr month

71. The outdoor exposure XI (C/kg) during the firstmonth was assessed by four different methods. withthe choice dependent upon the data available. If
continuous or daily data were provided, the exposure
rates were integrated. If incomplete data were provided. a n attempt was made to fit a power function of
the forn; a t h to the data. where t is time (days) and a
and b are constants to be determined. X , is then thein~egralof this function from arrival day I to day 30.
7 2 . If measurements of external gamma-exposure
rate were nor available, two approaches were used. If
data on the ground deposition of the radionuclides
were provided, the exposure rate from each wascomputed using the factors published by Beck [BlO]
for a relaxation depth of 0.1 cm. The term relaxation
depth follows from the assumption that the activity
mass concentration S(z) of a radionuclide decreases
exponentially with depth z in soil:

and the relaxation depth is defined by u-I. In this case,X , was evaluated as the sum of the integrated
exposure rate from each radionuclide.

73. In several cases, only data on the deposition of'"Cs were available. and XI was evaluated on thebasis of the relationship of the exposure to "'Cs
deposition density as measured at a specific location,e.g.. Neuherberg. Federal Republic of Germany [GI].
74. The effective dose equivalent during the firstmonth was calculated from X I by:

HL,c,= AXl(! - F,) + AXIF,,F,
where H,cel is the effective dose equivalent fromexternal exposure during the first month (Sv), A is theconversion factor (23.6 Sv per C/kg, i.e.. 33.7 Gy per
C/kg X 0.7 Sv/Gy), F,, is the indoor occupancy factor
and F, is the building-shielding factor. The values ofthe latter two factors are 0.8 and 0.2. the same as used
for the calculation of effective dose equivalent fromcloud-gamma irradiation.
(b)A.fier l h e j i r s l nronrll

75. The calculation of external gamma dose beyond
one month is based on the measured total depositionof "'Cs and I"Cs and, although less important, "'Ru,'06Ru and "'I. The conversion factors for long-term
deposition to dose rate depend on the penetration ofthese radionuclides in soil. Change with time isaccounted for by using factors appropriate for arelaxation depth of 1 cm during the first year and3 cm thereafter. The latter value had been previously
used by the Committee for its assessment of doses
from nuclear weapons fallout [U 1, U2].
76. Follouing the deposition of radioactive material
from the Chernobyl accident, several groups observedthat the measured external gamma exposure rate
decreased more rapidly over urban surfaces than overgrass surfaces [J2, K6. S18]. Although varied. theseresults are consistent with the loss of half of thematerial with a half time of 7 days and the other halfbeing firmly fixed on urban surfaces. This urban
runoff effect has been reflected in this assessment byapplying these factors to that portion of a country's
population considered to be urban.
77. The equation for the calculation of external
gamma effective dose equivalent for the time period
between one month and one year for radionuclide i is

H,,,(i)= [F(i)/i(i)J [Qe2(i)(e' 'f"13'12- e-""l")I[ I - F,(I - F,)][1 - Fp(l - F,)]
where H,,,(i) is the external gamma effective dose
equivalent for the time from one month to one year(Sv); F(i) is the deposition density (Bq/mz): @,:(i) isthe deposition density to effective dose equivalent
conversion factor during the period between one
month and one year (relaxation depth of I cm) ( S V per
Bq/m2); i.(i) is the radioactive decay constant (a I); F,
is the urban fraction of a country's population; F, isthe fraction of the deposition that remains fixed on
urban surfaces (assumed in this Annex to be equal to0.5) and F,, and F, are as previously defined.
78. The equation applies to the period between
30 days and I year. The overall reduction foroccupancy and shielding of buildings is 0.36 and the

reduction for urban areas is 0.75 with the assumed
parameters. The proportion of populations living inurban and rural areas is given in national statisticalreports. The urban proportion is around 80% in most
European countries, according to the various definitions of urban areas. However, as urban populations
also include people living in suburban locations, theurban fraction (F,). for purposes of this calculation,
was assunled not to exceed 0.5. Effective dose equivalent conversion factors are listed in Table 5.
Data were available from almost all countries in
Europe and elsewhere on the deposition of "'Cs. If
data \icere not reported for "'Cs. a measured ratio in
air was used, or a nominal ratio of 0.5. Data were also
typically available for "'I, but if not. deposition wasinferred based on ratios measured on airborne particles
or ratios of deposition in nearby countries. Data on'O'Ru and IUbRuwere available from about half of thecountries; if they were not, the calculations were madeon the basis of the ratio to I3'Cs measured in air ordeposition in nearby countries.
79.

4.

Ingestion

80. The ingestion of radionuclides in foods is asecond primary pathway for radiation doses. As
determined by an initial sensitivity analysis, only theradionuclides "'1, "4Cs and I3'Cs make significant
contributions and need be considered. The dose
estimation is based on measured or inferred concentrations during the first year, but projections are
required to take account of caesium transfer in futureyears.

8 1. The food categories considered include milk andmilk products, grain products. leafy vegetables. othervegetables and fruit. and meat. The occurrence of ')'I
in foods was of significance only for milk and milk
products and leafy vegetables, with the exception ofhigh relative values reported for the radish in Japan[N4]. Root vegetables and fruits were. in general. lessaffected, and they have been considered together. An
integrated food concentration (Bq a/kg) has been
calculated or inferred for each food category; it isbased on all types of individual foods to the extent
data were available. weighted by consumption amounts.
For esa~nple,the concentration for meal wascalculatedon the weighted average concentration in beef, pork.
lamb, poultry, game and fish. Similarly. the concentration in rnilk products was calculated as a weighted
average of the concentration in milk (of cows, sheep
and goats), cheese, butter etc.
82. Food consumption by adults has been takenfrom national estimates or from data tabulated by theUnited Nations Food and Agriculture Organization[FIO]. There are substantial variations in these values
from country to country. National consumprion estimates for infants were more variable than would bereasonable, probably because different age groups
were considered. Accordingly, consumption estimatesfor infants up to one year old were standardized andused uniformly in calculations for all countries: milk
products, 200 kg/a; grain products, 20 kg/a; leafy

vegetables, 5 kg/a; vegetables/fruit, 15 kg/a; and meat,
5 kg/a.
83. Doses from ingestion of contaminated foods arecalculated simply as the product of integrated concentrations in foods during the first year (from the
beginning of May 1986 to the end of April 1987).
consumption amounts and dose equivalent factors.
The integrated concentrations are summations ofmeasured values averaged over the regions considered.
In some cases, extrapolations were required to complete the full year of data.
84. If countermeasures were known to have beentaken in different countries, the effects were includedin the integrated concentrations in foods. For example,
Austria banned leafy vegetables, so the concentrationof ')lI in leafy vegetables is given as 0.0 [M3]. In othercountries. foods with radionuclide concentrations abovecertain limits were withheld from markets; any reported
concentrations in foods above that limit were therefore. disregarded.
85. Nearly all countries reported measurements of"'I in milk and leafy vegetables. Levels of I3Ts
and I3'Cs were usually reported for milk and leafy
vegetables. The reporting of concentrations in grain,meat and other vegetables and fruits was more
limited. Methods of inferring concentration varied
depending upon what other data had been reported
and the general relationships among food categories
deduced previously [UI]. The concentration of "'Csor 'j7Cs, if necessary. was typically inferred using afirst-year transfer factor. Specific values varied fromregion to region. As an example. "'Cs in meat wasestimated from 'j7Cs deposition using a first-year
transfer factor of 3-4 Bq a/kg per kBq/m2, in somewest European countries; in others, it was inferredfrom a ratio of integrated concentrations of meat tomilk of 2-3. The concentration in other vegetables andfruits was similarly deduced using a transfer factor of
0.8-1.6 Bq a/kg per kBq/m2 or by using a ratio of 0.3
for integrated concentration relative to milk. Grain
presented a special difficulty because measurements
were lacking and because some data showed a verystrong effect of time of contamination before harvest.
as noted earlier by Aarkrog [A4]. A more complete
discussion of how concentrations in grain were calculated is provided in the next section.
86. The equation for this part of the ingestion
pathway calculation for food category g and radionuclide i is
HE.$,(^) = Cp+(i)1,9g(i)where HE,gl(i)is the effective dose equivalent fromfirst-year ingestion of food group g (Sv); C;(i) is theweighted integrated concentration in food group g (Bqa/kg); I, is the consumption rate for food group g(kg/a); @,(i) is the effective dose equivalent per unit
intake from ingestion (Sv/Bq). Summation is required
over the relevant food categories for the total dose
equivalent from each radionuclide. Values of the dose
factors are listed in Table 6. Specific values ofconsumption rates are taken as reported by theindividual countries or as derived from F A 0 data
[FIO].

87. The dose assessment for the first year after the
Chernobyl accident depends on the use of measured
concentrations of radionuclides in foodstuffs. Such
concentrations are assumed to represent consumptionweighted averages for the area concerned. Reliable
estimates of such averages depend on systematic
sampling plans specially designed for this purpose.
For some types of foodstuffs. the prime example being
dairy milk, it is relatively easy to achieve reasonably
reliable estimates, because a measurement on a single
sample can be assumed to typify both a large production area and a large consumer group. For otherdietary components, reliable estimates necessitate bothlarge numbers of samples and well-designed sampling
plans. This is especially the case when there has beenboth small-scale and large-scale variability of thedeposition density, as was the case after the Chernobyl
accident.
88. After the Chernobyl accident. the affecred countries started sampling and measurement programmes.
These programmes were in many cases control programmes. designed to assure that foodstuffs contaminated above a particular level did not reach consumers.
Such programmes are often characterized by a plannedor unplanned bias, such that sampling is concentrated
in areas where high contamination levels are suspected. The average calculated from such programmes
therefore tends to overestimate consumption-weighted
averages. and there is little possibility of correcting
afterwards for a bias of this kind.
89.

For the long-lived caesium isotopes, there will bea time-averaging that results in less variability forcontamination levels in such foodstuffs as milk. green
vegetables and meat. Since the short half-life of "'I
precluded such averaging, the estimated average levels
must in many cases be regarded as tentative.
C.

CALCULATIONAL METHODSFOR PROJECTED DOSES
1. External irradiation

90. External exposure from radioactive materials
deposited on the ground was evaluated by thefollowing equation:
HF.c3(i)= [F(i)/i(i)J [@,,(i) e - ; ( ~ )[I~ ]- F,(1 - F,)][I - Fp(l - Fu)1
The symbols were defined in paragraph 77. The
deposition density to effective dose equivalent factor,@,,(i), to be used beyond one year after deposition,
uses a relaxation depth of 3 cm, as has been assumed
previously in UNSCEAR assessments. Values of thisfactor are listed in Table 5.
2.

Ingestion

91. Projections are required to estimate ingestion
doses beyond the periods for which measurements areavailable. Over many years, a deposition-diet transfer
model has been developed and used by the Committee

t o describe the behaviour of fallout radionuclides. *Sra n d "'Cs, in the environment and t o estimate dose
equivalent commitments [U I]. The basic transfer
relationship for radionuclide i and for food category gof the weighted diet total is:
C: (i) = Pz3(g,i) F(i)where C:(i) is the integrated concentration in foodover all time (Bq a/kg); P2,(g.i) is the transfer factor
from deposition density (compartment 2) to food o r
total diet (compartment 3) (Bq a/kg per Bq/mz); andF(i) is the total deposition density (Bq/m2).
92. The values of deposition density and concentrations in food have been determined on an annual basis
a n d the parameters in the transfer function evaluatedby regression fitting. The model for the transfer
function is
P2! = b, + b2 + b3e-"
where b , is the component of first-year transfer; b 2 isthe second-year transfer; and b,e-" is the subsequenttransfer (the latter accounts for both environmental
loss and radioactive decay). Tliis model was developed
for the rather more uniform a n d continuing deposition
pattern of radioactive fallout from atmospheric nuclear
weapons testing. Thus it is not specifically intended to
predict time-integrated concentrations in foods inspecific countries for a release such as that which
occurred from the Chernobyl reactor. However, inso far as seasonal and local conditions are largely
accounted for by direct measurements of the first year,
the model may be applied t o obtain projected behaviour
for the second year and beyond over large areas, suchas groups of countries. The part of the transfer
function that accounts for the time-integrated concentrations beyond the first year, the second and thirdterms, is referred to as P21.2+:= b 2 + b?e-"
P2>.?_
93. Detailed evaluation of the P, factor for ''-Cs for
all food categories is available from fallout measurements in Denmark and .4rgentina, reported in [ U I]. A
similar analysis has been made for Chicago in the
Lnited States [E7]. The values of these parameters arelisted in Table 7. The three locations are far apart. andthe results show some of the variability that can be
expected as a result of different soil types, agricultural
practices and other local conditions. These results
have been combined and the averaged values ofused in the dose calculations for all food categories
except grain products.
94. A separate assessment is required for grain
products, whose contamination has been shown to bevery dependent on the maturity of the plant [A4,C131. Contamination by root uptake is negligible incomparison to contamination by direct deposition. as
is generally the case for any vegetable product. Under
controlled conditions, the transfer of caesium to grain
has been studied in relation to time of harvest [A4].
Uniform deposition to a test area of a barley field
three months before harvest resulted in a 100-foldlower concentration in grain than applications twomonths before harvest. There was little difference intransfer for applications at other times within twomonths of harvest.

95. Grain is usually harvested in the summer months
and later processed into flour and bran or used a sanimal feed. The transfer factors from grain to breado r other products for human consumption and thecomposition of grains in the consumed products havebeen reported for Denmark [A5].

Rye
Wheat
Oats

Transfer fromgrain to bread

Percenrageof grain consumption

1
0.5
0.5

36
55
9

Applying these factors to the measured "'Cs activity
mass concentrations in grains harvested in 1986 resultsin P2, transfer factors of 0.5 Bq a/kg per kBq/m2 in
Finland; 0.25 in Norway, 3.3 in Denmark. 4 inFrance, 4.5 in Czechoslovakia and 16 in Japan. The
average P2, for grain products delivered after theatmospheric testing of nuclear weapons was 15 Bq a/kg
per kBq/m2 (Table 7). The latitudinal dependence of
the Chernobyl contamination reflects the different
stages of grain maturity at the time of the accident.
\+'here grain contamination is not reported for aparticular country, values of P,, for grain products
have been assumed to be 0.5 Bq a/kg per kBq/m2 forlatitudes above 55" N, 5 for temperate latitudes(40-55' N), and 20 for latitudes below 40° N. Higher
values are not likely because the grain at latitudes
below 30" N was about to be harvested when thecontamination occurred.
96. Assunling that the grain products derived from agiven summer harvest are available from November ofthat year to November of the follotving year, the grain
contaminated by the deposition in \lay 1986 can beconsidered t o have been distributed for six months(November to April) during the first year after theaccident and for six months during the second year. sothat b , = PI3/2 and P?,.?+ = P13/2.
97. Estimates of projected doses from the ingestion
pathway are obtained by multiplying the factor P_13.2+
by the deposition in the region, the consumption rate
and the dose per unit intake from ingestion:
where HE,g2(i)is the effective dose equivalent fromingestion of radionuclide i in food group g beyond thefirst year (Sv); P,,,,+(g.i) is the deposition density todiet transfer factor; F(i) is the total deposition density(Rq/m2): I, is the consumption rate (kg/a): and @,(i)is the effective dosc equivalent per unit intake (Srp/Bq).
98. Collective dose estimates are made for eachpathway by multiplying doses by the relevant population of each region. For the ingestion pathway two
estimates are made: namely, (a) a consumption-based
estimate, whereby the intake per individual is multiplied by the number of individuals and (b) a productionbased estimate which is derived from the country's total
production. The estimates are usually in fairly close
agreement, certainly within the uncertainty of the two
methods. The production-based estimates account for
any additional collective dose outside the country iflarge amounts of food are exported.

99. Countries were grouped together. and populationweighted values of deposition density and transfer
factors were used in evaluating the collective effective
dose equivalent commitments.

111.

EVALUATED lKPUT DATA

100. Following the Chernobyl accident, extensive
national monitoring programmes were undertaken to
determine the extent and degree of contaminationfrom the radionuclides released and to evaluate theneed for countermeasures. Continued measurements
in many countries of the environmental levels and ofconcentrations in the diet and in the human bodyprovide a basis for evaluating the radiation exposures.
101. The material in this chapter is not intended to
document the many results obtained; rather. it comprises, in summary form, the representative input datarequired for the dose calculations. In most cases, thesedata are the first-year integrated concentrations foreach country or subregion. Relationships between
integrated quantities have been used to check theconsistency of the results and to form the basis for
estimates where data are incomplete or missing. as
indicated in the previous chapter. The input data usedin the dose assessment are presented in tabular form,
and measured and inferred data are carefully distinguished.
102. Various types of input data are required tocomplete the dose calculations. These include nonradiological data, such as population, area. foodproduction and consumption, and radiation data.
such as integrated concentrations in air and foods anddeposition densities. The values of the non-radiolog~calparameters for each country or subregion are listed inTable 8. Food-production estimates, when not reported
directly by countries. were obtained from reports of
the Food and Agriculture Organization of the United
Nations [FlO. FI I], adjusted to reflect food-use
amounts by accounting for feed and non-food processed amounts. Other sources for non-radiological
data included publications of the United Nations andEuropean and other regional publications [E4. E5. E6,
P5:LT3].

-103. It has not been possible to substantiate fully allof the reported radiation measurement results. In
selecting representative values for specific regions,considerable care and judgement are required. Althoughscientists in each country were asked to review the
input data. some inconsistencies and questionablevalues remain. However. these should not affect themore general results of the assessment.
104. The sources of radiological data have been
numerous; some of the data was obtained directlyfrom scientists in the relevant countries and some of it
came from published reports. The references for thecountries are as follows: North Europe: Denmark [A3,
RI. R2]; Finland [A8. F1. 114, 115, N6, PI, R3, R7,
RIO, R11, R12, R13, S22. S23, S24. S25, S26. S27];
Norway [B4, B5, S14, S15, W3]; Sweden [A6. El. E8.

F4, F5. F6. H5, K2. K3, K 6 . 1 3 , S I . S 8 , S 9 , S131;
Central Europe: Austria [Al. B7, D2, F7, K7, M3,
0 1. S 18. S19, S201; Czechoslovakia [B 12. I1 I. M7.
M9); German Democratic Republic [LI]; Federal
Republic of Germany [B13. D4. D6. GI. 110. J5. K1.
S2. S16. W2, W4]; Hungary [A2, B9. HI. H4. S7];
Poland [CI, CZ]; Romania [R6]: Switzerland [B2. B3.
C14. HZ. PZ, S12. V2. W?]; West Europe: Belgium[CIO. G4,S4. S5]; France [C5, C21, C22. D3. 15, S3,
S17. S211; Ireland [C9]; Luxembourg [CIO. S3, S5]:
Netherlands [C8. C261; United Kingdom [C3. C11.
F2. F?. F12, 512, WI]; South Europc: Bulgaria [C1.
P41: Greece [G2, G3]; Italy [C15. C16. C17. C18. CIO.
C20. E2, M3, M5. M6. R4. R53: Portugal [L1]: S p a ~ n[C6. G5, G6]; l'ugoslavia [F8. F9. 17. 18. 531; USSR:[A9, 11. 12, 13. 14, 112. 113. 116. P6. US. U6]: \Vest.Asia: Cyprus [C12]; Israel [S6]: Syrian Arab Republic[Sl I]; Turkey [TI, T2]; East Asia: China [B8. C21,
L6]; India [Bl]; Japan [A7. NZ. N4. SIO]; North
America: Canada [C7, R8]: United Stales [DS, E3. Uj].
A.

AIR

1. Radionuclide composition
105. Radionuclides in air. identified by filter sampling.
\wre predominantly volatile clements (iodine, caesiun~,
tellurium) rather than non-volatile ones. The radionuclldes detected by gamma spectrometry included
J*Xlo. 9YmTc. ; O J R ~ , !::St,. 12%.
13:Te 1311 1321 1331.
13JCs. 1 1 6 ~ ~lj. :cs '"Ba, and "OLa. Some additional
radionuclides ('5Nb, lohRu."""Ag. I2'Sb. IzqmTe."lCc.
IJ4Cc) could be dctected only after the decay ofinterfering gamma lines.

.

. . .

106. Other radionuclides in air were determined bybeta or alpha spectrometry. Strontium radionuclides
were present in low concentrations, the "'CS/~"S~
ratlcl being approximately 110 to I as measured at
Xlunich-Ncuherberg and the "Sr/'*Sr ratio about 10
to I (on I May). Transuranic elements were estimatedto be present on I May at concentrations of 1 30pBq/m3(?''Pu). 200 pBq/m3 (:39.240Pu) and 1.500 pBq/m3(242Cm)[W4]. Other radionuclides assumed to havebeen present but which were below the detection limits
were 12"1 and ''C [W4]. The noble gases h5Krand l"Xe
were detectable in air. as was 'H in rain water.
107. The composition of iodine activity in air at thehiunich s ~ t eon initial arrival was found to be 40%
aerosol form. 35% elemental gaseous form and 25%
organically bound; however. these fractions changed
somewhat in subsequent days as rainfall depleted theaerosol and elemental forms more than the organic
form (Figure V) [W4]. The particulate iodine fraction
measured at Nurmijarvi in Finland on 28 April was
15% [S7] in a sample collected between 29 April and
2 May and 3-24% in samples collected through June[Sl]. Other determinations were 33% in Belgium on
2 May [S4], 29-3196 at two sites in Hungary on 2 and4 Ma); [HI], 50% on 29 April and about 33% on
following days in Austria [All, 20% on 4 May anddecreasing to 10% thereafter in Switzerland [H2]. 25%
in the United Kingdom during 7-12 May [C3], about
33% in China on 4-5 May [L6] and 30% on 5-6 May

-----

particles
gaseous..... o r g a n i c bound

Apri 1Figure V.

Measured concentrations of iodine-131 and caesium-137 in air at
Munich-Neuherberg, Federal Republic of Germany. [W4]in Japan [A7]. Over the monitoring period shown in
Figure V. the integrated concentration of I3'I was 23%
aerosol. 27% gaseous and 50% organically bound.
Approximately similar results were obtained for l3'l.
Ninety-eight per cent of "*Te was associated withparticles. as was 65% of its daughter '>:I. Of theremaining 132J,30% was gaseous and 5% organicallybound.

2.

Kay

Concentrations in air

108. The first arrival of contaminated air at theaffected places usually brought the peak concentrations of radionuclides in air. The continuing releases
from the reactor and the complex air movements oftencaused secondary peaks on subsequent days, as
illustrated in Figure V. The integrated concentrationsof radionuclides in air for the duration of elevatedlevels are listed in Table 9.
109. Reported peak concentrations of I3'I and I3'Cs
in air at several locations gives an indication of thelevels encountered. For "'I, the peak values were

400 Bq/rn3 at the Berezinsky National Park 120 km
north-east of Minsk, 300 Bq/m3 at Varyshevka 140 km
sourh-east of Chernobyl [I3], 210 Bq/m3 at Helsinki.
170 Bq/m3 at Vienna, 52 Bq/m3 at Munich-Neuherberg.
3 I Bq/m3 at Brussels. 2.5 Bq/m3 at Fukui and 0.3 Bq/m3
at Beijing. For I3'Cs, the peak values were 12 Bq/m3 at
Helsinki and Berlin, 9.6 Bq/m3 at Vienna, 9 Bq/m3 at
Munich-Neuherberg, 6 Bq/mJ at Brussels, 0.04 Bq/rn3
in Japan, and 0.02 Bq/m3 at Beijing.
110. Relationships between peak and integrated concentrations of radionuclides in air varied with local
meteorological conditions, the sampling times, andwhether more than one wave of contaminated air passed
the site. The quotients of integrated to peak air
concentrations (Bq h/m3 per Bq/m3) were comparable
for I3'I and Ij7Cs at individual sites. Values of thisquotient were determined to be 15 at Helsinki and
Nurrnijarvi in Finland, where a sharp peak occurred,
39 at four sites in Germany (West Berlin, Braunschweig, Karlsruhe. Neuherberg), 83 at two sites in
Hungary (Budapest, Paks), where three peaks occurred.
and about 70 in Japan (Chiba). where a more diffuse
peak occurred.

3.

Ratios of integrated concentrations

1 1 I. The radionuclide composition of contaminated
air masses varied depending on when the material had
been released from the reactor and the time it took fordispersion to the particular location. The ratios ofradionuclides of ruthenium, cerium and caesiumsuggest that the average irradiation periods of fuel inthe reactor had been 400-600 days during the initial
release period [C33.

112. The ratios of integrated concentrations in air
relative to 'j7Cs are listed in Table 10. The 1311/L'7Cs
ratio was around 25 in Scandinavia and 5-10 in mostother European locations. The 134Cs/137Cs
ratio varied
from 0.4 to 0.7 on separate days during May [C3,W4], but the rario of integrated concentrations was
relatively constant, around 0.5. in most places. The
ratios of other radionuclides to "'Cs showed somevariability. but there were no significant differences
between regions. The median values for all countries
are indicated in Table 10.

113. The ratios of refractory elements relative to
IJ7Cs differed significantly with distance from thereactor. For example. the ratios of 90Sr, I4'Ce and*j9Pu to IJ7Csin dust samples from within the Soviet

Figure VI.

Union were 35 times higher than in air samples inwestern Europe [A4]. The refractory components ofthe debris and also '"Sr were deposited closer to theaccident site than the more volatile constituents.
B. DEPOSITION
1. Deposition of caesium-137
114. The deposition of radioactive materials is associated mainly with rainfall. and since rainfall occurredvery sporadically throughout Europe during the passageof the contaminated air, the deposition pattern wasvery irregular. The highest deposition of "'Cs outside
the USSR was recorded in Sweden north of Stockholm,
where the deposition density exceeded 85 kBq/m2.
The region of Tessin (Region 1) in Switzerland
received 43 kBq/m2 and southern Bavaria in theFederal Republic of Germany up to 45 kBq/mZ. The
provinces of Upper Austria. Salzburg and Carinthia inAustria received estimated average deposition densitiesof 59,46 and 33 kBq/m2, respectively.
115. Average deposition densities for "'Cs of > I
and >5 kBq/m2 in Europe are illustrated in Figure VI.

Average caeslum-137 deposition density in countries or larger subregions in Europe.

325

Country-wide deposition densities of >5 kBq/m2 forentire country averages are indicated for Austria.
German Democratic Republic and Poland. Table I I
lists these average deposiiion densities.
1 16. The deposition of "'Cs and other radionuclides
outside Etirope and the USSR was, accordingly, muchless. Representative 4 u e s of l"Cs deposition densities
were 16-300 Bq/m2 i n Japan, 20-90 Bq/m2 in the
United States and 20-40 Bq/m2 in Canada.

2.

Deposition of other radionuclides

117. Radionuclides of importance to the external
gamma-irradiation dose from deposited materials
beyond the first month include "'Cs. 13JCs.'06Ru and'nlRu. The deposition of )"I, I3'Cs and "-Cs is ofimportance in determining doses from the ingestion
pathway. The deposition densities of these radionuclides in different countries and the ratios to "-Csare given in Table I I. The ratio of l J I I to "'Cs ishigher i n Norivay and Sweden than in other countries.
The ratios of other radionuclides to I3'Cs are relati~ely
uniform. The median ratios of radionuclide deposition
to that of "'Cs for all countries are "'Ru, 1.6; '"Ru.
0.5; '"I. 6.2; and '"Cs. 0.5.
118. On an individual measurement basis, there aredifferences of more than an order of magnitude in theratios of radionuclide depositions, particularly in theiodine/caesium ratio. Therc appear to be two reasonsfor this: the first is the difference in isotopic release atdifferent times during the course of the accident itself;
the second is the effect of differcnt rates of precipitation during the passage of the radioactive plume.

4.

External exposure from deposited materials

121. External irradiation from deposited radioactive
materials is. in the long term, due primarily to '"Cs
and 1J7Cs.In the first month after initial deposition,
however, a number of short-lived emitters, including
I3'Te, IJ2I, I j 1 I . I4OBa, 140La,Io3Ru and 1 0 6 R ~were,more significant contributors to the external exposure
rate.
122. The exposure rate in air from natural background is about 0.7 pC/(kg s). Off-site external exposure
rates i n air folloiving the accident were, at maximum.
40-60 pC/(kg s) at Kiev, USSR, 27 in south-west Finland; 12 at Sofia, Bulgaria; 12 at Salzburg, Austria;
7.9 at Munich-Neuherberg and 1.5 at Karlsruhe.
Federal Republic of Germany; and 1.4 at Athens.
Greece. The component of the external exposure rate
attributable to the Chernobyl release was typicallylower than the initial value by a factor of 5 by the endof the first month.
123. The exposure rates in air oirer the first month
have been summed in order to evaluate the specificcontribution of short-term emitters to effective dose
equivalent. These results have been norn~alized to"'Cs deposition density in Table 13. While the outdoor
effective dose equivalent in the first month is not due
primarily to I3'Cs, the normalized values can be useful for estimating effective dose equivalents where
measurements were incomplete or absent. Anomalies
in results can point to errors in data. With a few
exceptions, the results range from 5 to 40jtSv per
kBq/m2. The median value is 15pSv per kBq/m2.
These results are illustrated in Figure VII.

119. The release of radionuclides took place overabout 10 days and the fire spread through fuel ofvarying burnup and power rating, resulting in adifferent relative release of nuclides over the 10-day
period. Moreover, the plumes of radioactive material
left the Chernobyl site travelling in different directions
and were subjected to different meteorological conditions. Some experience showed that where the plumeradionuclide content was fairly similar. deposition was
related to the intensity of rainfall. Where the plume
passed and there was no rainfall. caesium deposition
tvas significantly less than that of iodine. Where it
rained through the plume, iodine deposition was
higher. and caesium deposition was similar to that ofiodine [Cl I].
3.

Quotient of deposition density andintegrated air concentration

120. Values of the quotient of the deposition densityof a radionuclide to its integrated concentration in air
depend on thc proportions of wet and dry deposition,
as well as on the nature of the particles or vapour andof the receiling surface. Table 12 lists these country
average results for "'Cs. The quotients are mostly inthe range between 0.6 and 1.2 cm/s. The higher values(those obsened. for instance. in Sweden and in
Ireland) are strongly influenced by rainfall.

Figure VII. Outdoor effective dose equivalent from external
Irradiation in the flrst month after the accidenl relative l ocaesium-137 deposition density. The regression line corresponds
to 15 pSv per kBqIm2.

C.

DIET

124. Ingestion of contaminated foods is an important
pathway leading to radiation doses from " l I and"'Cs, and all countries paid particular attention tothis pathway following the accident. These radionuclides are rapidly transferred to man through theconsumption of milk and leafy vegetables, following
their direct deposition on to pasture grass and plants.
Other basic foods. such as cereals, root vegetables.
fruit and meat. are produced during longer growing
periods and are. therefore, not so relevant for shortlived I3'I.
125. Numerous measurements are available for "'I
and 'I7Cs concentrations in foods in the first weeks
after the accident (data for "'Cs are available forlonger periods). The great variability in results reflected
the irregular deposition pattern. .4s indicated inchapter 11, attention often centred on the highest
levels in foods from areas of greater deposition:
however, for the dose assessment, i t is representative
levels in widely consumed foods that are needed.
Assessed results of representative integrated concentrations of "'1 and '37Csin foods during the first year
are given in Tables 14 and 15.
126. A degree of comparability between areas can beachieved by considering the integrated concentrations
in foods normalized to the deposition densities, andthis is the basis for the discussion below. Such relativetransfer factors can be used to help establish representative levels in foods from more widely based deposition measurements and to fill in gaps in food data. Of
course. the relative transfer depends on local conditions, such as feeding practice'during May 1986, so
differences in widely separated regions can be expected.
1. Iodine-131 in foods
127. Integrated concentrations of I3lI in milk andleafy vegetables relative to "'I deposition density arelisted in Table 14. In the case of "'I. there may besome additional variability because of uncertainties indetermining total "'I deposition. but a general pattern
emerges. In Scandinavia, cows were not yet on pastureat the time of the accident. By keeping cows indoors
for some days more. the integrated concentrations of"'1 in milk were kept rather low. Some grazing
restrictions were also imposed in the Netherlands. In
other areas, cows were already on pasture. Normalized
transfer of I3'I to milk ranges from 0.01 Bq a/kg
per kBq/mZ in Scandinavia to 0.1-1 in central Europe
and to 1-3 in some southern and Asian countries.
This suggests a latitudinal dependence, which in turnreflects agricultural conditions; this is illustrated in
Figure VIII. Only results based largely on measurements arc included. The probability distribution of
normalized integrated concentrations of "'1 in milk is
illustrated in Figure IX.
128. At several locations. concentrations of radioactivity in milk were higher for sheep and goats thanfor cows; this phenomenon is associated with differences in metabolism and feeding habits. For example.
during the first week after the accident, the average
concentrations of "'1 in milk in Greece were 9.000 Bq/l(sheep), 2.000 Bq/l (goats) and 200 Bq/l (cows) [G2].
If a non-typical food makes an important contribution
to radion~~clide
intake in a food category (milk or
milk products in this case), the food has been
included. weighted by consumption amount.
129. The extent to which "'I is transferred to leafy
vegetables depends on the growing season, which was
not far advanced in Scandinavia but was well under
way in southern Europe. The values of normalized
integrated concentrations in Table 14 generally reflect
this. The latitudinal dependence of all measured
values is illustrated in Figure VIII. The probability
distribution is shown in Figure IX.

Leafy

0.01

!

20

Flgure VIII.

I

30

I

40
50
LATITUDE (ON)

I

Y

60

I'

70

0.01 !
20

-

1

I

I

1

30

40

50

I

i

60

70

LATITUDE ( O N )Integrated concentretlons of iodine-131 In milk and leafy vegetables per unlt lodlne-131 deposltlon density.

iOO1

Elilk

0 Leafy vegetables

PERCENTAGE
Figure IX. Probability distribution of integrated concentrations of iodine131
In milk and leafy vegetables per unit iodine-131 deposltion denslty.

130. The ratios of integrated concentrations of "'I inleafy vegetables to those in milk are given in Table 14.
This comparison removes uncertainties in l3!I deposition, but there is still great variability among regions.
suggesting differences in definition of the individual
results, the use of milk of different sources, differencesin local agricultural practice and the effect of various
countermeasures. The majority of values of this ratio
lie in the range 1-5 with a median of 2.

2.

growth. Increases later in the year were due to the useof animal feeds produced earlier in the year. Thesechanges can be adequately modelled by an appropriate
choice of parameters [J5]. Similar variations havebeen noted elsewhere. Also shown in Figure XI1 is thecountry-wide average concentration of "'Cs in milk in
Finland [R3]. The initial peak was relatively small andoccurred a few weeks after the accident because thecows had initially been off pasture; also, the variability
with time was less marked, presumably because thedata came from wider-ranging samples.

Caesiuni-137 i n foods

131. The assessed first-year integrated concentrations.
norn~alizedto unit deposition density. of 13'Cs in thebasic food categories are listed in Table 15. These
concentrations are based on measurements, as reported
and averaged over the countries or subregions.
Generally the transfer for all food categories is higher
in southern Europe. The latitudinal dependence ofintegrated concentrations of "'Cs in foods is illustrated
in Figure X. The probability distributions of all
measured values are shown in Figure XI.
132. The ra~iosfor leafy vegetables/milk and formeat/milk are compared in Table 15. Relative to its
concentrations in milk, the integrated concentrationsof "'Cs in leafy vegetables are lower by a factor of
about 2 and in meat are higher by a factor of about 2,
with some deviations.
133. The longer-term monitoring of I3'Cs in milk
from a dairy farm in the south-eastern part of theFederal Republic of Germany [J5] gave the results
shown in Figure XII. Concentrations of "'Cs in milk
decreased through the summer of 1986, primarily
because the "'Cs was diluted in pasture grass of fresh

134. Country-wide monitoring results for I3'Cs inmeat in Finland are shown in Figure XIII. For
reference, the concentrations in milk are also shown.
The curve labelled "average meat" is weighted toreflecr average consumption of three parts pork forevery tivo parts beef. A beef/milk ratio of about 4 isseen to prevail and an average meat/milk ratio of
about 2. as referred to in paragraph 132. Owing todifferences in feed sources. the concentrations of I3'Cs
were generally lowest in pork and poultry, higher inbeef and lamb and highest in game.
135. Some foodstuffs that are consumed in small
amounts by most people or in large amounts byrelatively few people had. on average. much higher
activity mass concentrations of "'Cs than the foods
presented in Table 15. Foods that should be mentioned
in this regard are reindeer meat, mushrooms and lake
fish: (a) the feeding habits of reindeer (consuming
lichens) lead to exceptionally high levels of I3'Cs, as
was observed in the 1960s following atmosphericnuclear testing. After the accident. a large fraction of
the reindeer in Sweden had "'Cs levels of more than
10,000 Bq/kg [SI]: (b) enhanced levels of "'Cs havebeen found in mushrooms, although there was wnsider-

loO1
Milk

Grain
\

0-

m

0.1

t

I

I

I

I

I

20

30

40

50

60

70

0.1 !
20

I

I

30

40

LA1ITUOE ('11)

-

-

I

I

50

60

1

70

LATITUDE (ON)

1'1

Leafy vegetables

A
m

a

0.1

I
,
ao
io
50
io
-.a

20

40

50

60

I

70

50

LATITUDE (ON)

I

6'0

70

LATITUDE (ON)

100 7

-

Meat

.

Total d i e t

"E

c

A
CD

L

a
0

.u 7

10

2

+a

c

rn

z

0

r
U

<
1L:
L
W

e

3

C

I

0.1 20304050

LATITUDE ('11)

Figure X.

60

70

0.1 20304050
LATITUDE (ON)6070Integrated concentrations of c&eslum-137 in food8 and total dlet in the flnt year atler the accident
per unit caeslum~l37deposition density.

O.OD1

0.ooOl1-

Vegetableslfrui t (100)

]

I

2

5

I

10 15

io

30

5b

1

4b
60
PERCEIITAGE

I

70

1

I

I

7

90

95

98

Figure XI. Probablllty dlrtrlbutlon of Integrated concentratlons of
caeslum-137 In foods In the flrst year per unlt caeslum-137 deposltlon
denslty. Because of slldlng scale on left axls, multlply values by numbers
In parentheses. Geometric mean values are 2.7 mllk, 4.5 meat, 1.1 grain,
1.5 leafy vegetables and 1.6 vegetables/frult (Bq alkg per kBq/m2).

--

c:

A

- Fed. Rep. of GERMANY

B - FItiLAND

1

I

BO 85

I
10

Figure XII.

I

25

I
I
I
30
35
40
UEEK I H 1986

I

35

I
501

I

j

1

:n

I

15

I

20
HEEK 1;:

I

I

I

I

25
1907

30

35

40

Weekly monltorlng results of caerlum-137 concentrations i n mllk from the Federal Republlc ofGermany (dalry farm In south-eart Bavaria) and Finland (country-wlde mean).
155. R31WEEK I N 1986

WEEK I N 1987

Figure XIII. Country-wide mean concentrations of caeslum-137 in meat and milk In Finland[R3. R7]. (Meat average obtained by weighting according to consumption).

able variability depending on type and location. The
highest levels were measured in mushrooms of thefamily Boletaceae that live in symbiosis with trees(mycorrhiza), e.g.. in Xerocomus badius (Maronenrohrling). In this species, the 13'Cs levels were around
250 Bq/kg, but peak values of around 20.000 Bq/kg
were measured at the beginning of September 1986 in
the Federal Republic ofGermany [W2], and 800 Bq/kg
average and 7.800 Bq/kg maximum were measured in
the German Democratic Republic. also in September
1986 [Ll]. In other Boletaceae. e.g., the popular
Bolerus edulis (Steinpilz or ctpe). the levels were lower.
usually below 100 Bq/kg. In non-mycorrhizal mushrooms. e.g.. mushrooms of the genus Agaricus. such as
the common mushroom, "'Cs levels were very low;a n d (c) concentration of "'Cs in freshwater fish werein some places, e.g., Sweden, found to be many
thousands of Bq/kg, though there were large differences
between types of fish and even between nearby lakes[Sl]. Values of about 300 Bq/kg in plankton-eatinglake fish were measured in the Federal Republic of
Germany [W2]. Marine fish accumulate only very low
concentrations of "'Cs.
D.

THE HUMAN BODY

136. Following the accident, extensive measurements
were made of I3'I in the thyroid or "'Cs in the
body. The thyroid measurements were not always madein a standardized way, and much variability was
encountered. These results cannot, therefore. be easilyinterpreted. although they served as a guide to general
exposure levels. Measurements of thyroid burdens in

the Federal Republic of Germany that were intended
to evaluate estimates of "I1 intakes through inhalationand ingestion showed that those intakes were overestimated by a factor of about 5 [S16].
137. The amount of "'Cs in the body is generally
measured by whole body counting, which can be
performed in a reliable, comparable way. These
measurements enable a direct assessment of internal
doses from I3'Cs. Although ingestion was responsible
for most of the dose, the contribution from inhalation
could also be measured during the first few weeks
following the accident [O I].
138. Examples of I3'Cs body measurements in theFederal Republic of Germany. France and the United
Kingdom are presented in Figure XIV. Generally theamounts increased until late spring or early summer
1987. Regional differences are accounted for by thevarying levels of "'Cs in the diet. Lower body burdens
are accumulated in children and adult females than in
adult males as a result of shorter retention half-times
in the body [NI].
139. It is of interest to compare the internal doses
estimated directly from body burden measurements
and those estimated indirectly from concentrations infoodstuffs. Accordingly, the information on measured
body burdens in adults that was available t o theCommittee was processed to obtain time-integrated
body burdens corresponding to the "'Cs intakes
during the first year after the accident. The results,
presented in Table 16, are the integrated amounts inthe body (Bq a ) for one year (May 1986 to April 1987)

0k---.=--'
Hay ' June ' J u l y ' Aug ' Sept ' Oct
--

1

9

8

I

Nov

' Oec

Jan

' Feb ' M a r ' Apr I 3ay

I June1

69' July ' Aug0

I Sept I

Oct

I Nov I Dec

7

Figure XIV. Caesium-137 in the human body al Munich, Federal Republic 01 Germany (A: males; El: females; C: children) [S16];
in Oxfordshire, Unlted Klngdom (D: adults) [F2]; and In France (E: Grenoble, adults; F: Saclay, adulls) (J4, LS].

and include retention beyond one year of the acquired
body burden. The integrated "'Cs body measurements
range from 100-200 Bq a in areas of the United
Kingdom and France to 2,000-3.000 Bq a in Austria.
Bulgaria. Finland, Italy and Norway: in Japan, they
were 34 Bq a. The retention function for the adult was
taken to be 10% of the burden retained with a half-lifeof 2 days and 90% of that retained with a half-life of
110 days [I9]. This retention function was used toestimate the time-integrated body burdens during thefirst year, when the measured information was limited
to one or two points in time. and also to calcula~ethefraction of the time-integrated body burden attributable to retention beyond one year. Continuous intake
of 'I7Cs at a rate of 1 Bq/d gives an integrated
concentration in the body of 87 Bq a at the end of one
year and a further integrated concentration of 56 Bq afrom continued retention with no further intake.
Thus. 1 Bq/d for one year gives 143 Bq a in the bodyor 2.0 Bq a/kg, which results in an effective dose
equivalent of 5.0 ySv to reference man.
140. The body burdens expected from the "'Csconcentrations in diet have also been calculated, using
reported concentrations in foods for the area considered, when available, or, when not, assuming thatthe concentrations in foods are proportional to thedeposition density of "7Cs. The ratios of the bodyburdens derived from measurements in man and
expected from concentrations in diet are presented in
the last column of Table 16.
141. In general, the body burdens are less thanwould be expected based on deposition in the country
or subregion and on local concentrations of "'Cs infoods. The retention function was tested in a controlled
study and was found to be adequate [VI]. When foodbasket or total diet samples were measured, as wasdone in regions 2 and 3 in France, in Sweden and in
the Federal Republic of Germany, the agreement was
better. These findings call into question the representativeness of the concentrations in foods and theamounts consumed. This was certainly a factor in theplaces where people refrained from eating foodstuffs
expected to present higher-than-average "'Cs concentrations. Ingestion of less typical foods explain why
the measured body burdens of some people, e.g.,
Lapps (see the Norwegian data in Table 16), aregreater than those predicted from the average diet.
142. The "7Cs concentrations in foodstuffs may heoverestimates. These overestimates could have comefrom a sampling bias towards high deposition areas or
they could have been due to the fact that losses during
food processing or preparation are usually not taken
into account: also commercial distribution could cause
large scale movements of food and a smoothing of theconcentrations over entire countries. This may explain
why the measured body burdens in Oslo. Vienna, andregions I of Finland and France (low-depositionareas) were higher than predicted and why the reverse
was true in the high-deposition regions of Finland andFrance.

IV.

FIRST-Y EAR DOSE ESTIMATES

143. Exposures of populations to radionuclides
released in the accident have been calculated for all
countries for which measurements are available. These
include the USSR, most countries in Europe and a few
countries in Asia and North America. Thirty-fourcountries are considered here. The results are used.
first, as direct determinations of first-year doses and,second, as a basis for establishing transfer factors tobe applied for estimating doses in other countries of
the northern hemisphere.
144. The dose equivalents to individuals in theassessed countries during the first year following theaccident are presented in Table 17. These are thethyroid dose equivalents to infants and adults, primarily
from "'I. and the effective dose equivalents from all

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147. The calculated results for thyroid dose equivalents. and also for effective dose equivalents. take
into account. where possible, the application ofcountermeasures. This was usually done by adjusting
the integrated concentrations in foods so that thevalues represented what was actually consumed. However, the Committee has not taken into consideration
the use of thyroid blocking agents or stable iodine
preparations. By reducing uptake, these would haveafforded some additional protection against inhaled
and ingested radioiodine.

148. The country averages of infant and adultthyroid dose equivalents are listed in Table 18 andshown in Figures XV and XVI. Infant thyroid dose
equivalents in Europe generally ranged from 1 to
20 mSv. but there were higher doses in some parts of
Romania, Greece, Switzerland, Bulgaria and the
USSR. Adult thyroid doses were usually smaller than
infant doses in the same country by a factor of about
5 in central and western Europe, but the differenceswere smaller in northern Europe, where milk was lesscontaminated because the cows had not been on
pasture, and in regions of southern Europe and Asia,
where the contamination of leafy vegetables increased
adult thyroid doses.
149. The thyroid dose estimates are compared withthe estimates reported by individual countries in Table
18. The country-reported results are those collected by
the Nuclear Energy Agency of the OECD [N5].
Differences from unity in the ratios of the estimates to

Figure XVII.

the country-reported results reflect differences in thevarious assumptions regarding intake. the age groupings
for infants and the ways of accounting for countermeasures. The dose estimates are both higher andlower than those reported by the countries, but thedifferences are generally not greater than a factor of 4
for infants and a factor of 3 for adults.

B.

EFFECTIVE DOSE EQUIVALENTS

150. The effective dose equivalents recei~redby individuals (adults) during the first year following theaccident are presented in Table 17, which also showsrural-urban differences. Contributions to dose fromthe ingestion pathway also include committed doses
from caesiurn in the body following the first-year
intake of caesium in diet.
151. The highest average first-year committed effective dose equivalent in subregions was 2 mSv in the
Byelorussian Soviet Socialist Republic. Subregions
where effective dose equivalents were 1-2 mSv werelocated in Romania and Switzerland and 0.5-1 mSv inAustria. Bulgaria, Federal Republic of Germany.
Greece and Yugoslavia. The effective dose equivalent in
the Byelorussian Soviet Socialist Republic approached
the yearly effective dose equivalent due to naturalradiation sources. The mean values for each country
arc listed in Table 18 and plotted in Figure XVII.

Country-wide average first-year committed effective dose equivalents from the
Chernobyl accldent.

C.

152. These estimates of first-year committed effective
dose equivalent are in reasonable agreement with theresults reported by individual countries [N5],as is also
shown in Table 18. While there are some greater
discrepancies between these estimates and other.
provisional dose estimates [Ml. DS], the latter werebased o n measurements made in the first months after
the accident. Differences in estimates from countryreported results can be attributed t o the averaging ofresults over larger subregions, the inclusion of additional food groups and the use of different assumptions for occupancy. shielding and food consumption.
Most results from individual countries did not accountfor urban run-off. On average, however, the comparability of the Committee's estimates and those ofindividual countries is good. the average ratio being
1.06 with a standard error of 0.6.

100

153. The pathway contributions t o the first-year
committed effective dose equivalents varied substantially by location for all pathways except cloud
gamma, which was everywhere less than 1%. The
contribution from inhalation averaged 5%. with arange from 0.1% in Ireland to 22% in Turkey.

154. The first-year committed effective dose equivalents resulted primarily from the ingestion pathway.
which in most countries accounted for over 60% of
the total dose and in southern countries for over 80%.
The differences in pathway contributions are illustrated
in Figure XVIII for three groupings of countries:
southern countries (<40° N latitude), temperate countries (41°-55' N latitude) and northern (Scandinavian)

PATMWAY-

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-

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-

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latitudelatitudelatitudeTemperate
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countries
countries
FIRST-YEAR COfITRIDUTIDN

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F l g u r e XVIII.

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countries (>55ON latitude). The contributions tocommitted first-year effective dose equivalents average
I I%, 19% and 27% from external irradiation and
8695, 76% and 69% from ingestion in the southern,temperate and northern countries, respectively.
155. The pathway contributions to the thyroid dose
equivalents in the first year also varied from north tosouth. Average results for all age groups showed thesignificance of the ingestion pathway (through milk
and leafy vegetables), which was generally responsible
for over 70% of the total dose but in northern Europe
was responsible for only 40%. The inhalation pathway
contributed 20-50% of the first-year thyroid dose insome northern countries.

D.

RADIONUCLIDE CONTRIBUTIONS

156. Contributions to the first-year committed effective dose equivalents were dominated by the radionuclides 13'1, I3'Cs and I3'Cs. For the cloud gamma
and inhalation pathways, some other radionuclides in
air were important, specifically I3*Te and Io3Ru. For
the external irradiation and the ingestion pathways,
some other short-lived radionuclides were also significant. Caesium-137 and !34Cs together contributed
over 50% of the dose from ingestion in most countries. For the committed first-year thyroid dose
equivalent,
typically contributed over 90%.
157. A seasonal dependence of the radionuclide
contribution to the committed first-year effective dose
equivalent is indicated in Figure XVIII. The dosefrom "'I ranged from less than 4% in Scandinavia.
where cows were not on pasture and leafy vegetableproduction was minimal, to some 20% in countries atlower latitudes, where quite different agricultural
conditions prevailed. The iemainder of the main dose
contribution from IJ7Cs varied in an inverse way.
becoming increasingly more important in northerncountries.

E. TRANSFER RELATIONSHIPS
158. The input data for the assessment of thecommitted first-year dose equivalents have been basedon measurements through the first year. These can beanalysed to infer transfer relationships to dose equivalents. Because of the differences in local conditions

Radionuclrd~

Outdoor effecrivedose equrvolenr(irSv per kBq/mL)First monthAll
15
Second totwelfth monthCS-137
8.04
CS-134
18.6
Ru- 1030.69 1
Ru- 106
2.09
I- 131
0.0 15
Total (first year)

Shreldmg/
occupancy
facror

0.36

0.36
0.36
0.36
0.36
0.36

and varying assumptions with regard to food consumption and in determining integrated concentrations, it would not be reasonable to expect uniformly
consistent values of transfer factors. Nevertheless. it isuseful to indicate the range of values that applied toconditions at the time.
1.

Transfer from deposition to dosefrom external irradiation

159. Doses due to external irradiation from depositedradionuclides are delivered directly. The transfer
factor for external radiation in the first month after
the accident depended upon the presence of many
short-lived radionuclides. As shown in Figure VII. theaverage outdoor effective dose equivalent was around
15 j1Sv per kBq/m2 of 'j7Cs. This multiplied by theshielding/occupancy factor of 0.36 [0.2 (outdoor
occupancy) plus the product of 0.8 (indoor occupancy)and 0.2 (shielding)] gives an average contribution of
5 pSv per kBq/m2.
160. Transfer factors for the period between one
month and one year may be taken directly from
Table 5. For 117Cs.the value is 8.04 pSv per kBq/m2.
When this is multiplied by the shielding/occupancy
factor of 0.36 and the urban population/runoff factorof 0.75 [0.5 (rural population) plus the product of 0.5(urban population) and 0.5 (urban removal)], theaverage contribution from 'j7Cs alone is seen to be
2.2 pSv per kBq/m2.
161. The one-month to one-year transfer factors forother inlportant radionuclides in deposited material.
from Table 5, are 18.6, 0.691, 2.09 and 0.015 pSv
per kBq/m2 of I3'Cs, '03Ru, IMRuand I3lI,respectively.
I t is convenient to relate these further to Ij7Cs
deposition density by using median values of theratios of these radionuclides to 13'Cs in deposition.
These ratios are 0.5 for I3'Cs and Io6Ru. 1.6 for Io3Ru
and 6.2 for I ' I I (Table I I). The total contribution,using the same factors (shielding/occupancy andurban population/runoff), to the effective dose equivalent from these radionuclides per unit I3'Cs deposition density is 3.1 jlSv per kBq/m2.
162. The components of the first-year transfer toeffective dose equivalent due to external irradiationfrom deposited radionuclides relative to unit IJ7Cs
deposition density may be summarized as follows:
Urbon
popularion/
rutro/jjoc!or

Rorio
ro
cnesium-137

Tronsjerfocror
componenrr(pSv per kBq/m2)

2.

Transfer from deposition to thyroid dose equivalentof iodine-131

163. The derivation of the transfer factor from
deposition to thyroid dose equivalent in the first year
is presented in Table 19. Since the thyroid dose
calculation includes inhalation and ingestion contributions, some differences may result from relating thetotal dose only to IJ1I deposition.
164. The results vary by orders of magnitude. Thevery 10~9values for Scandinavian countries reflect theearly stage of the growing season there and theconsequently low transfer to milk and leafy vegetables.
The relatively high values are due to several factors. In
southern countries, animals were already on pastureand in addition. in some areas contributions fromextensive use of sheep's milk was included, in which
the concentrations were about 10 times higher than in
cow's milk. Protective actions that were taken further
increased the variability of these results. The latitudinal

-

io

jo

40
5'0
LATITUDE (ON)io

7bFigure XIX. Transfer factor for infant thyroid dose equivalentfrom ingestion and inhalatlon relative to iodine-131 deposition
density.

dependencies in the transfer factor from deposition to
thyroid dose equivalent from "'I for infants andadults are shown in Figures XIX and XX.
3.

Transfer from deposition to dose from ingestion of
caesiurn-137(a)Transfer from deposirion to dier

165. The quotients of the first-year integrated concentrations of "'Cs in foods and the "'Cs deposition
density, which were presented in chapter 111 (Table 15)
for the individual food categories, define the first-year
deposition to diet transfer factors for lJ7Cs, the b,
values. These values have been combined and weighted
by consumption amounts to obtain the averagedeposition to first-year total diet transfer factors foreach country or subregion listed in Table 20. Also
listed are the average integrated concentrations of"'Cs in diet and the total first-year intakes of "'Cs.
166. The results of first-year transfers of lJ7Cs tototal diet under the conditions that prevailed at thetime of the accident are included in Figure X. The
least-squares fit through the measured values shows atrend toward increasing transfer per unit deposition at
southern latitudes, as seen also in the individualcomponents of diet from first-year measurements (alsoin Figure X). Most countries and subregions intemperate latitudes are in the range 1-4 Bq a/kg
per kBq/m2. There are, however, greater deviations insome countries that reported higher levels in foods
than would have been expected from estimated deposition. In some cases, there is uncertain transfer to somefood items as well as higher transfer to diet due to theinclusion of certain foods, such as milk and meat fromgoats and sheep. I t would be of interest to study inmore detail the local conditions that cause deviations
from the more widely applicable transfer factors
derived here.
167. The log-normal distribution of b, transfer factors
for "'Cs in total diet is shown in Figure XXI. A single
population-weighted value is plotted for each country:
for some countries. the values were largely inferred.
but these have also been included. The values range
from 1 to 9 Bq a/kg per kBq/m2, with a geometricmean of 2.6 Bq a/kg per kBq/m2. This mean may becompared with the average value of 4.1 Bq a/kg per
kBq/m2 (range 1.9 to 6.3) for the first-year transfer offallout "'Cs. derived from long-term measurements(Table 7).
(b)

1,

20

.

I

I

I

I

30

40

50

60

70

LATITUDE (O::)
Flgure XX. Transfer factor for adult lhyrold dose equlvaientfrom ingestion and inhaiatlon relative lo iodine-131 deporltlon
density.

Transfer from dier to body168. The transfer factor from diet to body burden,
P,,, is derived in Table 20. The integrated concentration of '"Cs in the body is obtained by multiplying
the dietary intake of IJ7Cs in the first year by astandard factor, 143 d/70 kg (the mean residence timeof "'Cs in the body divided by the body mass). The
integrated concentration includes retention in the
body beyond the first year. The transfer factor fromtotal diet to body burden is the ratio of integrated
concentrations in the body and in diet. Variability inthis factor reflects only differences in food consump
tion. The median value for this transfer factor is
2.9 Bq a/kg per Bq a/kg.

Figure XXI. Probability distribution of caesium-137 in first year total
diet relative to caesium-137 deposition denslty.

(c)Transferfrom bodv to effecrive dose equivalenr

169. The transfer factor from IJ7Csin the body to theeffective dose equivalent, P,,, is based on the dose factor
given in Table 6. For adults. this factor is 0.014 pSv per
Bq intake. The retention function for caesium in the
body was discussed in paragraph 139. Since the mean
retention time is 143 days, an intakeof I Bq corresponds
to 1 Bq X 143 d + 70 kg = 5.6
Bq a/kg in the body.
The transfer factor from integrated concentrationin the body to the effective dose equivalent is0.014 + 5.6 lo-', or 2.5 uSv per Bq a/kg.
170. The overall transfer factor from deposition to
the first year effective dose equivalent. P2J.I,is obtainedby sequential multiplication of the transfer factors P,,(which is referred to as bl for the first-year transfer). P,,
and Pas. These values for the ingestion of "?Cs in
countries or subregions are listed in the last column ofTable 20.

V.

DOSE COMMITMENTS

171. Dose equivalenr commitments have been calculated using transfer factors developed and used by
the Committee for its assessments of the dose commitments resulting from atmospheric nuclear weapons
tests [UI, U2]. Since those transfer factors weredeveloped for the rather more uniform and continuous
deposition patterns of fallout, they are here applied
only to regional groups of countries. Because first-yeardoses were for the most part calculated from measured
data. only the components of the fallout models
corresponding to transfers beyond the first year
following deposition were taken into consideration.
For that time, i.e.. more than one year after theaccident, the only pathways to be considered areexternal irradiation due to activity deposited on the

ground and ingestion of foodstuffs. and the only
radionuclides that contribute significantly to the dose
equivalents are 134Csand 137Cs.For these radionuclides, the effective dose equivalent and the thyroid
dose equivalent have the same value for a given
exposure.
172. The methods for obtaining projected dose
estimates were discussed in section 1I.C. After specificvalues for the transfer factors have been derived, they
are applied to the average I3,Cs and "7Cs deposition.
Since the IJ4Cs to I3?Cs deposition ratio was uniform
in all countries, the contributions to the dose fromboth radionuclides may be related to the L37Cs
deposition value.
A.

TRANSFER RELATIONSHIPS

1.

Transfer from deposition to dosefrom external irradiation

173. Values of the effective dose equivalent per unit
deposition density of radionuclides for the period after
one year are given in Table 5. These apply to a soil
relaxation depth of 3 cm. Assuming an initial runoff
loss of one half of deposition in urban areas, equal
proportions of urban and rural residents, a shielding
factor of 0.2 indoors and an indoor occupancy factorof 0.8, the transfer factors for the dose per unit
deposition from external irradiation beyond one year
are 7 1 pSv per kBq/m2 for I3'Cs and 9.8 pSv per
kBq/m2 for I3'Cs. An additional small contribution of
0 . 4 , ~ per~ s ~kBq/m2 comes from lo6Ru. Using a valueof 0.5 for the deposition ratio 1J4Cs/'37Csas well as
for 106R~/1"Cs,the total dose may be estimateddirectly from "'Cs deposition: 76 pSv per kBq/m2. The
derivation of this transfer factor may be summarized
as follows:Radionuclide

Ourdoor effecrivedose equivalenr(pSv per kBq/rn2)

Shielding/ocrupancy
facrorLlrhanpopular~on/
runo//jocror

Rarro
10

coes~um-137

Transfer facror
cornponenrs(PSI' per kEq/ml)

Total for theperiod beyond 1 year

2. Transfer from deposition to dose from ingestion(a)Transfer front dcposirion 10 dier174. The model for the transfer from deposition todiet is:PZj= bl + b: + b3e-"
where b2 is the second-year transfer and b3e->' is thesubsequent transfer. in which the elimination of radiocaesium by environmental and physical processes istaken into account. The transfer from deposition todiet beyond the first year is thus represented by:
Values of P,,,, and PzSderived from long-term fallout
measurements of IJ7Cs are given in Table 7. For all
foodstuffs except grain products, the average values ofPz3,?-given in Table 7 were used for "7Cs in all of thelarge regions considered in the assessment: 2.1. 1.4. 2.0
and 8.0 Bq a/kg per kBq/m2 for milk products, leafy
vegetables, vegetables/fruit and meat. respectively. In
the case of grain products, the value of P23.2+for "'Csin a large region was assumed to equal the populationweighted mean of the b l values estimated for that
region (see paragraph 96).
175. The deposition to total diet transfer factor is
obtained by weighting the values for the food groups
by consumption amounts. Population-weighted foodconsumption estimates for the large regions consideredin the commitment assessment are listed in Table 21.
The regional value for the transfer factor for grain
products is given along with the weighted total diettransfer factor.
(b)Transfer from diet lo body176. The transfer factor from total diet to bodyburden, P,,, is the quotient of normalized bodyburden and normalized dietary concentration. These
values vary only because of consumption differences.
The value can be derived by multiplying total foodconsumption (kg/a) by 143 Bq d per Bq (residence
time in body) and dividing by 365 d/a and 70 kg(body mass). The results are listed in Table 21. The
median value for these large regions is 2.8 Bq a/kg per
Bq a/kg.
fc)

Transfer front body ro e f l e c ~ i ~ dose
* c equiralen I

177. The transfer factor from the time-integrated
concentration in the body to the effective dose
equivalent, Pd5. is, for IJ7Cs, equal to 2.5pSv per
Bq a/kg, as derived in paragraph 169.

178. The overall transfer factor for 'j7Cs from
deposition to total diet to body to effective dose
equivalent in the time period beyond the first year,
P,.,-. is given in Table 21. The values average 20pSv
per kBq/m2 in the northern and temperate countries
and about 25 pSv per kBq/m: in southern countries.
179. The transfer of '"Cs from deposition to effective
dose equivalent may be related to I3'Cs deposition,
taking into account the lower deposition (1'4Cs/137Cs=
0.5) and the higher dose per unit intake ("4Cs/'37Cs =1.4). This gives effective dose equivalents from " T s
70% of those from lJ7Cs in the first year. Subsequenttransfer is less because of the shorter half-life of "'Cs.
but most significant transfer to most foods occurs
within the first feu? years of deposition. Average
results for all countries show the "'Cs ingestion doseto be 65% of that from l"Cs. corresponding to 70% of
the first-year '"Cs dose and 60°/0 of the subsequent"'CS dose.
B. AVERAGE DOSE EQUIVALENTCOMMITMENTS I N LARGE REGIONS
180. The effective dose equivalent commitments fromall radionuclides released in the accident are evaluatedin Table 22. These are the average results for the large
regions. The first-year dose is the population-weighted
result of the effective dose equivalents given in Table 18.
The component of dose from exposure or intake after
the first year is determined by multiplying the population-weighted I'*Cs deposition density in the region by
the total Pz,,. transfer factor. comprising external
gamma exposure (invariant across regions and derived
in paragraph 173) and doses from "'Cs and lJ4Cs infoods (derived in paragraphs 178 and 179).
181. The results range from 1,ZOOpSv in southeastern Europe (Bulgaria. Greece, Italy, Yugoslavia),
970 j~Sv in Scandinavia, 940pSv in central Europe,
SZOpSv in the USSR and 510/1Sv i n eastern Mediterranean countries to 20 1rSv or less in other regions.
These results are illustrated in Figure XXII. Further
evaluations of regional effective dose equivalent commitments are presented in the following section, V1.C.

C.

PATHWAY AND RADIONUCLIDECONTRIBUTIONS

182. The relative contributions of external and internal irradiation to the effective dose equivalent com-

COLLECTIVE DOSE COMMITMENT

VI.

185. On the basis of available measurements, calculations have been completed of the first-year doses in
34 countries and the dose commitments in several
large regions. Using transfer factors derived fromthese results, dose estimates may be made for theremaining areas of the northern hemisphere. These
areas, generally far removed from the accident site,
received only trace deposition of radioactive materials
and therefore make only small contributions to thetotal collective dose equivalent. Nevertheless. forcompleteness. the entire northern hemisphere is considered in the dose assessment. This is done in two
steps: (a) by considering the relationship between
deposition and distance to estimate "'Cs deposition in
all regions; and (b) by applying a general transfer
factor based on I3'Cs deposition to estimate theeffective dose equivalent commitment from all pathways and all radionuclides.
A.

Figure XXII. Regional average effective dose equivalentcommitments from the Chernobyl accident.

mitment vary from one region to another. The
external irradiation dose pathway becomes relatively
more important as time goes on, and is the dominant
contributor to the effective dose equivalent commitment in all but the southern countries. The median
contributions to the effective dose equivalent commitments from external irradiation and ingestion areapproximately 60-40% in northern countries, 5545%
in temperate countries and 45-55% in southern countries.
183. Caesium-137 is the dominant radionuclide contributing to the effective dose equivalent commitment,
accounting for about 75%, 70% and 65% in northern,temperate and southern countries, respectively. Becauseof its shorter half-life, I 3 T s contributes much less tothe effective dose equivalent commitment than I3'Cs
via the external exposure pathway. Overall, thecontribution of II4Cs to the effective dose equivalentcommitment is about 20% of the total in all regions.
The contribution from ')'I ranges from less than 1%
in northern countries to about 10% in southerncountries. The remaining 4% or 5% of the effective
dose equivalent commitment comes from other radionuclides that caused exposures within the first year.
184. The pathway and radionuclide contributions to
the effective dose equivalents, including both the firstyear components and the contributions over all time,
are illustrated in Figure XVIII.

CAESIUM- 137 DEPOSITION WITHDISTANCE FROM CMERNOBYL

186. I t may be expected that radionuclide deposition
and radiation doses generally decrease with distancefrom a release by virtue of geographic spreading anddilution in the atmosphere. Of course, there may besignificant variations within the first hundreds ofkilornetres, depending on the exact course of theplumes and the rainfall pattern. In the case of theaccident at Chernobyl. however, the release lasted
several days, during which the wind changed to all
directions. so even these variations were minimized.
187. Figure XXIII shows the relationship between
I3'Cs deposition and distance, based on measurementsin the 33 assessed countries outside the USSR. Thereis seen to have been a relatively uniform decrease in
the average 13'Cs deposition density with distancefrom Chernobyl. An envelope of points is shown
along with the central power-function curve, fromwhich the I3'Cs deposition densities in the various
regions are estimated. The average I3'Cs deposition
densities in the five main regions of Europe, based on
measurements, are shown.
188. In Figure XXIII the distance to a particularregion is the population-weighted average of the
distances to the capital cities or to the approximate
population centres of the countries in the region. The
average I3'Cs deposition density in the region is thenselected from the central curve in Figure XXIII.
B. TRANSFER FACTOR FOR TOTAL DOSECOMMITMENT BASED ON CAESIUM-137
DEPOSITION
189. For the purpose of estimating exposures fromthe Chernobyl accident in countries for which measurements are unavailable, it is necessary to have a generaltransfer factor that accounts for the total effective
dose equivalent commitment from all radionuclides
and all pathways based on extrapolated estimates of
I3'Cs deposition density.

outhwest Asia.. .:. ':'Scuth Asia
. . . . . . . % o r t h A t l a n t i c Ocean

Central and Rest A f r i c a..Central Asia
Southeast Asia

Southwest Europe..

...........Cariobean
Country reasurenwnt
0 Regional average
0 Xegional estimate

0.001. ' . . . .Central Anerica'.... North P a c i f i c Ocean

I
100

1000

10000

100000D?STAtlCE FTO!! CHECNOBYL (km)Figure XXIII.

Deposition density of caesium-137 with distance from the Chernobyl reactor.

190. The first component of this transfer factor fromexternal irradiation was derived in paragraphs 159-161
and 173. The summary values are entered in Table 23,
which compiles the general transfer factors for southern(<40°), temperate (4!-55') and northern (>55O) latitudinal regions. For external irradiation, the same
assumptions are used for all regions, so the components of the transfer factor per unit '"Cs deposition
are the same.
191. Because of differences in agricultural conditions
in countries at the time of the accident, somelatitudinal dependence must be introduced into thecomponents of the transfer factor from the ingestion
pathway. The transfer factors to effective dose equivalent for '37Csfrom first-year ingestion were derived inTable 20. The population-weighted values for northern,temperate and southern latitudes are approximately 15,
20 and 25 pSv per kBq/mZ. The values for I3'Cs. basedon '"Cs deposition amounts, are 70% of the corresponding values for 'j7Cs. These estimates areentered in Table 23.
192. After the first year, the transfer factor components for lJ7Csingestion are 20 pSv per kBq/m2 at
northern and temperate latitudes and 25pSv per
kBq/m2 at southern latitudes (Table 21 and paragraph178). The corresponding estimates for "'Cs are 60%,of the 13'Cs estimates (paragraph 179).
193. Regional (i.e., northern, temperate or southern)values of "'I transfer factors may be selected from

Table 19 and from Figure XX. Based on the fit tocalculated values for individual countries or their subregions. approximate average values are 5, 50 and
100pSv per kBq/m2 for countries at northern, temperate and southern latitudes, respectively. These are
the thyroid dose equivalents relative to I 3 ' I deposition
density. The contribution to the effective dose equivalent is obtained by multiplying them by the weighting
factor for the thyroid (0.03). The transfer factor may
be based on Ij7Cs deposition by multiplying further by
the average ratio of "'I to 'I7Cs deposition. 6.2(Table I I ) . The resulting transfer factor components
for "'I. for the first year only, are 1, 10 and 20pSv
per kBq/m2.
194. The components of the transfer factor based on
I3'Cs deposition to effective dose equivalent commitment from the two major pathways and from thedominant radionuclides are summarized in Table 23.
I t must be understood that these factors apply to theconditions at the time following the accident and to
the average composition of radionuclides in thedispersed material as observed. The latitudinal differences apply only to the ingestion pathway.
C.

ESTIMATES O F COLLECTIVE EFFECTIVE
DOSE EQUIVALENT COMMITMENT

195. Estimates of collective dose equivalent commitments for all regions of the northern hemisphereare compiled in Table 24. To allow an estimate to bemade of the total release of '"Cs. this listing includes
also the ocean areas north of the equator. The country
populations given in [U3] have been adjusted, basedon individual country growth rates, to values appropriate for 1986. The population of the northernheniisphere (4.3 10') makes up 88'3 of the total world
population.
196. The effective dose equivalent commitments inthe large regions (Table 22) were estimated on thebasis of measurements in the first year and projections
for subsequent times. The estimates for European
regions are carricd forward to Table 24. with a few
additional countries having been included in someregions. The product of pop~ilationand effective dose
cquivalsnt comnlltnient is the estimated collective
effective dose equivalent commitment.
197. Countriesoutside Europe but still in the northernhemisphere (i.e.. the countries of .4sia, North America
a n d parts of Africa and South America) have beengrouped in several regions. 'The population-weighted
distances to individual countries are used as the
distances to the regions for the purpose of estimating
average !I-Cs deposition (1-igure X X I I I ) . For theseregions. all of ~ h i c hlie at southern latitudes (<40°).
the transfer factor 190 pSv per kBq/m2 (Table 23) isused. The estimated effective dose equivalent commitments for all geographical regions are illustrated in
Figure XXII. hlultiplication by the populations of theregions gives the collective effective dose equivalentcommitments.
198. The total collective cffecti1.e dose equivalentcommitment from the accident is estimated to be
600.000 man Sv. From Table 24. it is seen that 53% isexperienced in turopean countries. 36':i in the USSR.
8% in Asia. 2% in Africa and 0.3% in North, Central
a n d South America.
199. Alternative estimates of collective effective dose
equivalent commitnient have been made for the
34 countries for which more detailed radiological data
were available. These estimates are based on the total
production for human consumption of foods in all thecountries. There is no need t o consider where thefoods are consumed. The collective effective dose
equivalent commitment estimates based on production
are generally in close agreement with the estimates
based on individual consunlption rates in countries
and populations. The production-based est~rnatedtotal for all 34 countries is just 10% greater than the
consumption-based estimate.
200. I t is difficult to assess the uncertainty in theCommittee's estimates. Much of the dose commitment
has not ye1 been experienced. a n d can only becalculated on the basis of projection models. The
general methodology for projections used by theCommittee, has been detteloped after some years ofstudying the transfer factors for "'Cs. the radionuclide of primary concern. The comparison of thecalculations b) the Cornniittee for the first year andthe calculations by individual countries (Table 18)
showed reasonable agreement. When the first-year
integrated body burdens calculated by the Committee

are compared with the actual measurements (Table 16).
i t can be seen that the estimate of effective dose
equivalent commitment from ingestion may be highby perhaps 50%. As discussed above, a possible
explanation for this discrepancy is the difficulty ofknowing the radionuclide content of what is acrually
being consumed, given the limitations of food-samplingtechniques. The Committee believes, accordingly, thatits estimate is unlikely to be an underestimate of theeffective dose equivalent commitment that will actuallyoccur but that it might be an overestimate by a few
tens of per cent.

D. COLLECTIVE DOSE COMMITMENTPER UNIT RELEASE
20 1. From estimates of the average 'I-Cs deposition
density in the regions included In Table 21. anestlmate can be made of the total amount of "'Cs
rclcased in the accident, independent of estimates that
could be made near the reactor site at the time of theaccident. The sum of the products of average deposition density and area for all land and ocean regions
gives an estimated total Il7Cs deposit of 70 PBq. Of
this total, some 42% was deposited within the USSR.
37% in Europe. 6% in the oceans and the remainder inthe other regions of the northern hemisphere.
202. This estimated "'Cs total deposit in the northernheniisphere may be conipared with the original "'Cs
release estimate of 38 PBq 50% (Table 1). Theseestirnates arc in reasonable agreement, given themagnitude of the uncertainties associated with eachestimate. The estimated release of 70 PBq would
correspond to about 25%, of the "'Cs calculated tohave been in the reactor core.

+203. The reported release of "'Cs from the damaged
reactor was about 10% of the core inventory (Table 1).
Based on the higher estimate of "'Cs release and on
the activity relationship. the "'Cs release could havebeen 35 P B q . corresponding to a percentage release of
Itif;. If the release of ' " I . originally estirnated t o havebeen 2 0 5 of the total "'1 in the core, was, instead.
25%. the estimated release would be 330 PBq.
204. From the calculations or estirnates of thecollective el?ective dose equivalent commitments listed
in I'able 24, i t may be determined that 430,000 man Sv
is due to Ii7Cs. 120.000 man Sv to "4Cs, a n d
37.000 man Sv (collective effective dose) to "'1. The
remaining 20.000 man Sv was contributed by shorterlived radionuclides deposited immediately after theaccident.
205. From these values, the collective effective dose
equivalent commitments per unit release of the major
radionuclides may be estimated as follows:"'Cs: 430,000 man Sv/ 70 PBq = 6 IO-"man Sv per Bq"'Cs: 120,000 man Sv/ 35 PBq = 3 10-"man Sv per Bq1311: 37,000 man Sv/330 PBq = 1 10-"man Sv per Bq
For the thyroid dose equivalent from 13'I. the estimate
would be the above value divided by the thyroid
weighting factor of 0.03.

206. These estimates pertain to the particular conditions that prevailed at the time of the accident, butthey may be a useful point of reference for this type ofradiation source. For comparison. the collective effective dose equivalent commitments per unit releasefrom another source. atmospheric nuclear testing. are
as follows [UI]:
I3'Cs: 2,200.000 man Sv/960 PRq=2 10-"man Sv per Bq
110,000man Sv/700EBq=2 10-lbman Sv per Bq

1311:

These resulted from releases largely into the stratosphere and apply to world populations of 3.2 lo9
persons (for "'1) at the time of the main releases and4 lo9 persons (for I3'Cs) during the main exposure
period. Because the fallout frorn weapons tests was
injected into the stratosphere, a longer time elapsed
for decay of "'I before deposition.
207. Estimates of collective effective doses per unit
release have also been made for modelled dispersion
from nuclear installations (Annex B). Based on a
population density of 25 persons per km:. theseestimates are [W'5]:
13'Cs:5 lo-'? man Sv per Bq"'1: 4 10 I' man Sv per Bq
E.

COLLECTIVE DOSE COMMITMENTS
FROM OTHER RADIONUCLIDES

208. This assessment has accounted for the mainradionuclides contributing to the collective dose. A
few other radionuclides in the release from theaccident \\,ere widely dispersed and could be considcrcd
as additional contributors to the total collective dose
commitment. For completeness, the collective effective
dose equivalent commitments may be summarized asfollows:

Radonurlrde

Rdcase
(PBq)

H-3
C- I4
Kr-85
Xe- 133
1- 129

0.005
33
1700
0.00003

Total

7

CoI/rrrr~c, ~ / / l v c t l v<10\1*,~
cqurl ~ I / ~ + I I I
Dosr factor
rommrrmcnr(man St pcr P B y ) Inrun .\v)

0.4
I 10000
0.2 1
0.05
170000

I
5 50
7
85
5

650

209. The amounts of noble gases 85Kr and "'Xe in
the reactor core, which were assumed to bc entirely
released, \\ere given in Table 1. Releases of 'H. "C,and '?'I were not reported, but their generation rates
in the reactor are assumed, roughly. to be 1,000, 10
and 0.05 GBq per M W a. respectively. which may becompared to the BJKrgeneration rate of 14.000 GBq
per M W a [W5]. The percentage release has beentaken as 100% for IH and (as for I3'Cs) 2 5 9 for I4C
and "'I. The 1291 dose has been truncated at 10.000
years. The doses from lz9I and ''C are delivered overlong times but at very low dose rates. The collective
effective dose equivalent commitment from theseradionuclides is negligible.

VII.

SUMhlARY210. The accident at the Chernobyl nuclear power
station was a serious occurrence. indeed a tragic eventfor the people most closely affected in the USSR. The
material costs of control. resettlement and decontamination have been enormous. Some of the people who
dealt with the emergency lost their lives. Although
populations were exposed in the countries of Europe
and, to a lesser extent. in countries throughout thenorthern hemisphere. the radiation exposures were. inperspective. not of great magnitude.
211. The detectability of radiation in very small
concentrations has allowed extensive measurement of
the released radioactive materials in the environment,
and i t has been possible to make a complete inventoryof "'Cs, the main component of the release. The
amount 70 PBq of "'Cs corresponds to 22 kg of
caesium, which was. however, dispersed across anentire hemisphere of the earth. Radionuclides area unique class of substance whose environmental
behaviour can be studied in detail at such trace levels.
212. I n Europe. the highest effective dose equivalentsin the first year were 760jrSv in Bulgaria, 670 j1Sv inAustria. 590 pSv in Greece and 570 1rSv in Romania,
follo\ved by other countries of northern. eastern andsouth-eastern Europe (Table 18). For reference, theaverage annual effective dose equivalent from natural
sources is 2.400 pSv. The doses in countries farther tothe west in Europe and in the countries of Asia. Africa
and North and So~lthAmerica were much less, whichis in accord with the deposition pattern.
2 13. Exposures, mainly from released "'Cs, willcontinue for a few tens of years from the external
irradiation and ingestion pathways. Estimates of dose
commitments have been made for larger geographicalregions, based on projection models developed fromfallout measurement experience. Transfer factors
derived for northern, temperate and southern latitudes
provide estimates of the effective dose equivalentcommitment from all radionuclides and all pathways
referred to the deposition density of '"Cs. From the"-Cs deposition versus distance relationship, dose
estimates for the entire northern hemisphere are
obtained. The estimated coUective effective dose equivalent commitment from the accident is of the orderof 600.000 man Sv.

2 14. This assessment of radiation exposures from the
Chernobyl accident has dealt with the main radionucltdes and pathways that contribute to the collective
dose. I t is recognized that many more features of
exposure from other radionuclides and other pathways have been and continue to be investigated invarious countries. The Committee will undoubtedly
wish to review these findings in the expectation thatthey will lead to a better understanding of the
behaviour and effects of radionuclides in the environment and to improved methods for assessing radiation
exposure.

T a b l e

1Core l n v e n t o r v and e s t l m a t e of t o t a l r e l e a s e o f r a d l o n u c l l d e ?
1111

Radlonuc 1l d e

a/
-

b/
C/

Half-llfea/Inventory(Em)

Percentage
releasedb/

C/

Reference: [ I S ]Decay c o r r e c t e d t o 6 Ray 1986.
S t a t e d a c c u r a c y : f SOX, e x c e p t f o r n o b l e gases.

T a b l e2

A c t l v l t v r a t l o s o f r a d l o n u c l l d e s released I n t h e Chernobyl a c c l d e n tr e l a t l v e t o caeslum-137
[I31

Date

Zr-95

Ru-103

Ru-106

1-131

30 A p r l l 1986
1 Hay 1986
2 Ray 1986
4 Ray 1986
6 Hay 1986

0.4
1.5
6 .
5.3
11

2.1
5.2
2.9
5.2
6.4

0.3
0.8
0.8
1.1
3.8

4.0
13
4.1
6.2
4.1

Ba-140Ce-141

Ce-144

5.7
9.6
5.1

0.6
3.2
5.5
4.8
10

0.7
5.5
4.3
3.8
11

T a b l e

3

Lffectlve dose eaulvalent factors for cloud q a m Irradlatlon
IK51

Radlonuclidea/

Effective dose equlvalent
per unlt tlme-Integrated
concentratlon In atr(nSv per 00 d/rn3)

Includes daughter radlonucllde.

T a b l e

4

Oose equlvalent factors for the lnhalatton of radlonucllder[H3. N31

Radionucl lde

InhaThyroid dose equivalentlatlon per unlt Inhaled actlvlty
class(nSv/Bq)

a/
-

Sr-89
0
Sr-90
0
Zr-95
w
Y
Nb-95
no-99 b/ Y
Ru-103 b/ Y
Ru-106 b/ Y
Ag-llOm b/ Y
Cd-115Y
Sb-125W
W
Sb-127
Te-129m b/ W
Te-131111&/ W
Te-132 b/ W
D
1-131
1-133
0
0
Cs-1340
Cs-136
Cs-137 b/ 0
0a-1400W
La-140Ce-141Y
Ce-143Y
Ce-144 b/ Y
Np-239Y

a/ 0, W ,Infants
-

8.0
22
2.2
0.42
0.23
0.82
12
38
0.12
2.1
0.39
1.1
180
260
2200
420
6.5
4.2
5.6
1.5
0.20
0.039
0.045
1.4
0.043

Effectjve dose egulvalent
per unlt Inhaled actlvlty(nSv/Bg)

Adults
-

0.41
2.2
0.78
0.36
0.033
0.26
1.7
6.4
0.018
0.32
0.062
0.16
33
58
2 70
44
11
1.7
7.9
0.26
0.069
0.025
0.00620.29
0.0058

Infants

Adults

21
130
26
27
7.9
8.0
900
21 0
8.9
27
12
4.7
21
37
66
14
7.3
4.7
6.4
8.2
8.6
17
6.8
700
4.7

1.8
59
4.3
1.6

-

1.1

2.4
130
22
1.1
3.3
1.6
6.5
1 .6
2.5
8.1
1.5
13
2.0
8.6
1 .O
1.3
2.4
0.92
100
0.66

Y refer to retentlon tlmes In the lungs (days, weeks andyears, respectlvely).
b/ Includes daughter radtonucllde.

T a b l e

5Effectlve dose equlvalent factors
for external l r r a d t a t l o n f r o m d e ~ o s l t e d r a d l o n u c l l d e s
ta101

Effectlve dose equlvalent
per u n i t d e p o s l t l o n d e n s l t y
f o r outdoor e x p o s u r e( n S u per ~q/rnZ)
Radlonucltde
3 0 d a y s t o 1 )ear

T a b l e

After 1 y e a rbDose equlvalent f a c t o r s f o r the l n a e s t l o n of r a d l o n u c l l d e s[H3, N31

Radlonuc 1 lde

Thyrold dose equlvalent
per u n l t lngested a c t i v i t y(nSv/8~)
Infants

Adultsfffectlve dose equivalent
per unlt lngested actlvlty( nSv/Bq)
Infants

AdultsT a b l e

7

Parameters of caeslum-137 d e D o s l t l o n t o d l e t t r a n s f e r f u n c t i o n
d e r i v e d from l o w - t e r m f a l l o u t measurements[Ul.E71( 8 9 a/kg p e r k8q/mL)-transferbl

Transferbeyondf l r s t year
P23,2+

Total
transfer
P23

TOTAL D I E T
Argentina
Denmark
Unlted States

6.3
4.0
1.9

1.8
8.0
3.5

8.1
12
5.4

Average

4.1

4.4

8.5

F l r s t year
Country

M \ l k products
Argentlna
Denmark
Unlted States
Average
Graln products
Argentlna
Den~rkUnlted States
Average
Vegetables
Argentina
Denmark
United States
Average
Frult
Argentlna
Denmark
Unlted States
Average
Meat
Argentlna
Denmark
Unlted States
AverageT a b l e

8Area, population. food productlon and food consumptlon In assessed countrtes

Area

(

lo3 km2)

Food consumptlon per caput( kg/aFood roductlon( 1 0 kg/a)t

Population(lo6)

Country
Infants

NORTH EUROPE
Denmark
Flnland
NorwaySwedenReglon 1
Reglon 2
Reglon 3
CENTRAL EUROPE
AustrlaCzechoslovakia
Reglon 1
Reglon 2
Region 3
German Oem. Rep.
Reglon 1
Reglon 2
Reglon 3
Germany,
Fed. Rep. of
Reglon 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Regton 2
PolandRomanlaReglon 1
Reglon 2
Regton 3
Switzerland
Reglon 1
Reglon 2
Reglon 3
Reglon 4
W E S T EUROPE
Belglum
FranceReglon 1
Reglon 2
Region 3
Ireland
Luxembourg
Netherlands
Untted Kingdom
Reglon 1
Reglon 2
Regton 3
SOUTH EUROPE
Bulgarta
Reglon 1
Region 2
GreeceReglon 1
Reglon 2
Italy
Regton 1
Reglon 2
Portugal
Spaln
Reglon 1
Region 2
Yugoslavia
Region 1
Reglon 2
Reglon 3

Total

Ullk
prod.

Graln
prod,

Leafy
veg.

Veg./
frult

neat

Mllk
prod.

Graln
prod.

Leafy
veg.

Veg./
frult

Heat

Table 8, continued

Area(103 km2)

Populatlon(lob)

Food production(106 kg/a)

Food consumptlon per caput(@/a)

Country
Infants Total

Milk
prod.

Graln
prod.

Leafy
veg.

Veg./
frult

Meat

Mllk
prod.

Graln
prod.

Leafy
veg.

Veg./

Heat

frutt

USSR
207.6
269.4
485.1
4532.616696.3

0.17
0.35
0.51
2.47
2.12

10.01
21.94
29.80
139.7077.37

6360 1300
10800 3050
8270 1780
49300 20900
17900 10000

217
785
474
4630
1180

754
2270
1510
14800
5670

1040
1800
1300
9400
3600

332
332
332
332
332

133
133
133
133
133

37
31
37
37
37

118
118
118
118
118

63
63
63
63
63

WEST ASIA
CyprusIsraelSyrla
Turkey

9.3
20.7
185.2
774.8

0.01
0.08
0.18
1 .OO

0.64
3.87
8.98
52.00

50
20
470
200
1100 1900
5000 20000

100
660
300
5000

100
950
1500
20000

50
220
200
2000

83
120
10
125

94
130
190
200

87
140
30
100

315
190
340
150

83
60
22
40

EAST ASIA
Chlna
India
Japan

9571.33287.3358.8

18.63 1046.39
25.38 750.90
1.43 121.01

5380 216000 28400 170000 30000
26300 120000 18900 61000 3060
4660 13500 5600 16800 16900

5
39
50

229
183
193

29
28
30

173
89
180

30
5
120

NORTH AMERICA
CanadaUnited States

9215.49372.60.38
3.754550 10600
39400 71800

281
5970

181
114

93
91

21
25

301
260

130
146

Region 1
Region 2
Reglon 3
Reglon 4
Reglon 525-36
238.745080 3980
61600 31700

T a b l eCountry
SORlH EUROPE
Denmarkf InlandNorwaySwedenReglon 1
Reqlon i
Reglon 3

Sr-90

Zr-95

no-99

0.012

CENTRAL EUROPE
Austrla(0.58)
C~echoslovakla
Reglon 1
Regton 2
Reglon 3
German Oem. Rep.
Reglon 1
Reqlon 2
Reglon 3
Germdny. Fed.Rev.of
Reqlon 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Reglon 2
PolandRomdnlaReglon 1(1.2)
Reglon 2(1.9)
Region 3(1.5)
kltzerland
Rcqlon 1
Reglon 2
Reglon 3
Reqlon 4
YES1 EUROPE
Belgiumf rance
Reg lon I
Reglon 2
Reglon 3
Ireland
Luxembourg
Netherlands
Unlted Klngdorn
Reglon 1.2
Reglon 3
SOUTH EUROPE
Bulgarla
Reglon 1.2
GreeceReqlon 1
Reqlon 2
Italy
Reglon 1
Reylon 2
Portugal
Sva l nReqlon 1
Reglon 2
Yuqoslavla
Reglon 1
Reqlon 2
Reqlon 3

0.05

0.05

1 .O
1 .O

USSR
Reglon 1
3.7
Reqton 2
2.4
Reqlon 3
0.7
Reqlon 4(0.5)
Reqlon 5(0.02)*EST ASIA
CyprusIsraelSyrlan Arab Rev.
lurteyEAST ASIA
Chlna
Indla
Japan
NORTH AMERICA
CanadaUnlted Stateshunbers In parentheses are Inferred values.

Ru-103

Ru-1061-13]

9Te-132

Cs-134

Cr-136

Cs-137

8a-I40Ce-141

Ce-144

ND-239

T a b l e

10

Ratlos of tnteqrated concentrations of radlonuclldes ln alr to caeslum-137

Country
NORTH EUROPE
Denmark
Flnland
NorwaySwedenReqlon 1
Reqlon 2
Reqlon 3
CENTRAL EUROPE
AustrlaRu-103

2.2
0.28
(2.0)
1.3
1.4
1.9
(2.0)

Czechoslovakia
Reqlon 1
1.3
Reqlon 2
1 .6
Reqlon 3
2.4
German Dem. Rep.
Reqlon 1
0.61
Reqlon 2.3
0.72
Germany.
fed.Rep.of
Reqlon 1
1.3
Reglon 2
1.3
Reqlon 3
1.3
Hungary
Reqlon 1
4.0
Reqlon 2
3.5
Poland2.5
RomanlaReqlon 1
1.3
Reqlon 2
5.0
Reqlon 3(3.6)
Swltzerland(1.9)
Reqlon 1
Reqlon 2(1.9)
Reqlon 3
(1.9)
(1.9)
Reqlon 4
NEST EUROPE
Belqlumf rance
Reqlon 1,2,3
Ireland
Luxembourg
Netherlands
Unlted Klnqdom
Reqlon 1,2
Regton 3
SOUTH EUROPE
Bulqarla
Reqlon 1.2
GreeceReqton 1
Reglon 2
Italy
Reqlon 1
Regton 2
PortugalSpa 1nReqlonl
Reqlon 2
Yuqoslavla
Reqlon 1
Reqlon 2
Reqlon 3

1.3
1.5
1.5
1.3
1.3
1.9
1.9

3.1
4.0
4.0
1.8
1 .8
(2.0)
(1.5)
(1.5)
1.8
1.5
1 .8

USSR
Reqlon 1
Region 2
Reqlon 3
Reqlon 4
ReqlonS

1.1
1.2
1.4
1.4
(1.3)

Ru-lob

1-131

Te-132

Cs-134

Cs-136

Ba-140Ce-141

Table 10, continued

Country

Ru-103

Ru-106

WEST ASIA
CyprusIsrael
2.2
Syrian Arab Rep.
Turkey3.3

1-13] le-132

Cs-134

(2.9)
3.1
(5.3)
2.4

5.4

(0.50)
0.52(0.50)
0.51

0.78

4.8

2.2

Cs-136

Ba-140Ce-141

2.3

EAST ASIA
Chlna
Indla
Japan

(1.4)
(2.1)
(2.5)

(0.30)(0.30)(0.50)

(6.7)
5.0
12

(3.9)
(0.47)(3.9)(0.51)
0.29
0.50(0.15)
0.10(0.12)(0.59)
0.29(0.07)NORTH AMERICA
CanadaUnlted States

(1.3)
(2.4)

0.52
(0.30)

2.5
(10)

(4.0)
(1.7)

(0.50)(0.50)(0.20)(0.50)MEDIANVALUES

1.5

0.37

8.2

4.2

0.50

0.19

0.50

0.69

0.13

Numbers In parentheses are Inferred values.

T a b l e

11

De~osltlonof radlonuclldes

Deposltlon denslty(k8q/m2)
Country
NORlH EUROPE
Denmark
FlnlandNoruaySuedenReglon 1
Reglon 2
Reglon 3
CENTRAL EUROPE
AustrlaCzechoslovakla
Reglon 1
Reglon 2
Reglon 3
German Oem. Rep.
Reglon 1
Reglon 2
Reglon 3
Germany.
Fed. Rep. of
Reglon 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Reglon 2
PolandRomanlaReglon 1
Reglon 2
Reglon 3
Sultzerland
Reglon 1
Reglon 2
Reglon 3
Reglon 4

Ru-103

Ru-106

1-131

Cs-134

Ratlos of deposltlon denslttes
to caeslum-137
Cs-137

Ru-103

Ru-106

1-131

CS-134

Table 11, cont\nued

Oeposltlon denslty(kBq/mZ)
Counrry

Ru-103

Ru-106

1-131

Cs-134

R a t l o s of d e p o s l t l o n d e n s l t l e s
t o caestum-137
Cs-137

Ru-103

Ru-106

1-131

Cs-134

1.6

0.5

6.2

0.5

W E S T EUROPE
0elglum
FranceReglon 1
Regton 2
Reglon 3
Ireland
LuxemDourg
Netherlands
Unlted K l n g d o mReglon 1
Reglon 2
Reglon 3
S O U T H EUROPE
Bulgaria
Region 1
Reglon 2
GreeceRegion 1
Reglon 2
Italy
Reglon 1
Reglon 2
Portugal
Spain
Reglon 1
Reglon 2
Yugoslavla
Reglon 1
Reglon 2
Reglon 3
USSR
Realon 1
Reglon 2
Reglon 3
Reglon 4
Reglon 5
NEST ASIA
CyprusIsraelS y r l a n A r a b Rep.
TurkeyE A S T ASlA
Chlna
Indla
Japan
hORTH AMERICA
CanadaUnited S t a t e s-p~

M e d i a n values
N u m b e r s I n Darentheses a r e I n f e r r e d v a l u e s .

T a b l e

12

Q u o t l e n t s o f d e D 0 5 l t l o n d e n s l t y and t l m e - l n t e q r a t e d c o n c e n t r a t l o n I n a l r
f o r caeslum-137

Country

Oeposltlon
d e n s l t y a/
( k8u/rn2)

NORTH EUROPE
DenmarkFInland
NorwaySwedenCENTRAL EUROPE
AustrlaCzechoslovak!aGerman Oem. Rep.
Germany. Fed. Rep. o f
Hungary
PolandRomanlaSvltzerland
WEST EUROPE
Belglum
FranceIreland
Luxembourg
Netherlands
U n i t e d Klngdom
SOUTH EUROPE
Bulgarla
Greece
Italy
PortugalSpa lnYugoslavla

8.5
4.8
4.8
0.02
0.03
14

USSR

1.4

1.3
11
1.1
9.5
23
4.2
7.2
5.1
2.7
5.2
(9.4)
3.4

0.84
1.1
3.3
2.1
1.8
0.9

WfST ASIA
CyprusIsraelS y r i a n Arab Rep.
TurkeyEAST ASIA
Chlna
Indla
Japan

(0.15)
0.035
0.18

NORTH AMERICA
CanadaUnlted States

0.030
0.026

a/

(0.6)
(0.4)
(0.13)
4.0

A r e a - u e l g h t e d average values.

Integrated
concentratlon
I n a i r a/
(Bq d/m3)

Ouotlent(cm/s)

T a b l e

13

Outdoor effective dose equlvalent ln the flrst m o n t hfrom external lrradlatlon per unit caeslum-137 deposltlon

Country

NORTH EUROPE
Denmarkf inlandNorwaySwedenReglon 1
Reglon 2
Reglon 3
CENTRAL EUROPE
AustrlaCzechoslovakia
Reglon 1
Reglon 2
Reglon 3
German Oem. Rep.
Reglon 1
Reglon 2
Reglon 3
Germany.
Fed. Rep. of
Reglon 1
Reglon 2
Region 3
Hungary
Reglon 1
Reglon 2
PolandRomanlaReglon 1
Reglon 2
Reglon 3

Switzerland
Reglon 1
Reglon 2
Reglon 3
Reglon 4
WEST EUROPC
Belglum
FranceReglon 1
Reglon 2
Reglon 3
lreland
Luxembourg
Netherlands
United K l n g d o mReglon 1
Reglon 2
Reglon 3
S O U T H EUROPE
Bulgarla
Reglon 1
Reglon 2
GreeceReglon 1
Reglon 2
Italy
Reglon 1
Reglon 2
PortugalSpa 1 nReglon 1
Region 2
Yugoslavla
Reglon 1
Reglon 2
Reglon 3

Effectlve
dose
equivalentI n flrst
month

Populatlonuelghted
deposltlon
denslty of
caeslum-137(usv)(k8p/m2)

Effectlve
dose
equivalent
per unlt
caeslum-137
deposltlon( u S v per k8p/m2)

Table 13, contlnued

Effectlve
dose
equivalentI n flrst
month

Populationuelghted
deposltlon
densIty of
caeslum-137(usv)(k8q/m2)

Effectlve
dose
equivalent
per unIt
caeslum-137
deposltlon( ~ S Vper k8q/m2)

Reglon 1
RegIon 2
Region 3
Reglon 4
Regton 5

1200
860
190
86
(1.3)

39
15
10
2.8
0.09

31
59
19
31
(14)

WEST ASIA
CyprusIsrael
SyrIan Arab Rep.
Turkey

(5.6)
(5.6)
(3.9)
5.6

(0.6)
(0.4)
(0.1)
4.0

(9)
(1 4 )(39)
1(0.13)(0.13)

0.03
0.026

(4)
(5)

Country

USSR

EAST ASIA
Chlnd
IndIa
Japan
NORTH AMERICA
CanadaUnlted States

Numbers In parentheses a r e lnferred values.

T a b l e

14lodlne-131 In foods

Integrated concentration(Bq a/kg)
Country

CENTRAL EUROPE
AustrlaCzechoslovakla
Reglon 1
RegIon 2
Reglon 3
German Dem. Rep.
Reglon 1
Reglon 2
Reglon 3
Germany.
Fed. Rep. of
Reglon 1
Reglon 2
Reglon 3
Hungary
RegIon 1
Reglon 2
Polandconcentrations

Leafy
vegetables

Leafy vegetables/mllkproducts

Ratlo oflntegrated

Latl tude(degrees
north)HORTH EUROPE
Denmarkf Inland
NoruaySwedenRegIon 1
Reglon 2
Reglon 3

Normallzed
Integrated concentration( B q a/kg per k8q/m2)

Mllk
products

Leafy
vegetables

MI lk
products

T a b l e 14. continued

Country

Latitude(degrees
north)

Integrated concentration(Bq alkg)

Normallzed
Integrated concentratlon( B q a/kq per k8q/m2)

Ratlo oflnteqrated
concentratlons

MI lk
products

Hllk
products

Leafy vegetables/mllkproducts

Leafy
vegetables

RomanlaReqlon 1
Reglon 2
Reglon 3
Sultzerland
Reglon 1
Reglon 2
Reglon 3
Regton 4
KEST tUROPL
Belqlum
FranceReqlon 1
Reglon 2
Reglon 3
Ireland
Luxembourg
Netherlands
Unlted Klngdom
Reglon 1
Reglon 2
Reqlon 3
S O U T H EUROPE
Bulqarla
Region 1
Reglon 2
GreeceReqlon 1
Reqlon 2
Italy
Reglon 1
Regton 2
PortugalSpa l nReqlon 1
Reglon 2
Yuqoslav\aReglon 1
Reglon 2
Reglon 3
USSR
Reqlon 1
Reqlon 2
Reglon 3
Reglon 4
Reglon 5
Y E S T ASIA
CyprusIsraelSyrlan Arab Rep
TurkeyEAST ASIA
Chlna
Indla
Japan
NORTH AMERICA
CanadaUnlted States
Numbers ln parentheses a r e lnferred values.

Leafy
vegetables

T a b l e

15

Caeslum-137 ln foods durlns the flrst year

Integrated concentration(8q a/kg)

Normallzed lntegrated concentratlon(8g a/kg per k8~/m2)

Ratlo of integrated
concentrations

Country
nllk
prod.

Graln
prod.

Leafy
veg.

Veg./
frult

neat

nllk
prod.

Graln
prod.

Leafy
veg.

Veg./
frult

neat

Leafy veg.
/ mllk

neat/
mllk

90
23
26
6.0
6.0
21
4.2
(1.7)
(0.16) (0.05)

25
17
10
(2.1)
(0.04)

200
33
8.0
55
10
50
(2.6) 14(0.06) (0.50)

2.3
1.8
2.1
1.5
(1.7)

0.6
0.4
0.6
(0.6)
(0.5)

0.6
l .2
1.0
(0.8)
(0.4)

0.9
0.6
1.0
(0.9)
(0.6)

5.2

0.3
0.7
0.5
(0.5)
(0.3)

2.2
2.1
2.4
3.3
(3.1)

NORTH EUROPE
Denmark
ilnlandNOrva ySwedenReglon 1
Reglon 2
Reglon 3
CENTRAL EUROPE
AustrtaCzechoslovakia
Reglon 1
Reglon 2
Regton 3
German Oem. Rep.
Reglon 1
Reglon 2
Reglon 3
Germany.
Fed. Rep. of
Reglon 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Reglon 2
PolandRomanlaReglon 1
Reglon 2
Reglon 3
Sultzerland
Reglon 1
Reglon 2
Reglon 3
Reglon 4
HEST EUROPE
Belglum
FranceReglon 1
Reglon 2
Reglon 3
Ireland
Luxembourg
Netherlands
Unlted Klngdom
Reglon 1
Regton 2
Region 3
SOUTH EUROPE
Bulgarla
Reglon 1
Reglon 2
GreeceReglon 1
Reglon 2
Italy
Reglon 1
Reglon 2
Portugal
Spaln
Reglon 1
Reglon 2
Yugoslavla
Reglon 1
Reglon 2
Region 3
USSR
Reglon 1
Reglon 2
Reglon 3
Reglon 4
Reglon 5

3.8

5.0
5.1
(5.3)

Table 15, contlnued

Integrated concentration(Bq a m )Country

Ratio of lntegrated
concentrations

nllk
prod.

Leafy veg.
/ mllk

neat/
mllk

nllk
prod.

Graln
prod.

Leafy
veg.

Veg./
fruit

WEST ASIA
CyprusIsraelSyrlan Arab Rep.
Turkey

(3.0)
(0.8)
(1.0)
21

(2.0)
4
(0.3)
2.0

(3.0)
(5.0)
(0.05)
6.5(0.6) (2.0)(2.0) (10)(0.02) (0.3)
3.5
17

(5.0)
(3.3) (5.0)(2.0) (lo)
(13)
(1.7)
(2.3) (0.4)
5.3
1.6
0.5

(1.0) (3.3)(5.0) (25)(0.2) (2.3)
4.3
0.9

(1.0)
(6.3)
(0.05)
0.3

(0.7)
(13)
(0.3)
0.8

EAST ASIA
Chlna
lndla
Japan

(0.18) (0.47) ( 1 . 1(0.16) (0.39) 0 . 1
0.22
0.056
0.29

(0.19) (0.78)(0.046) (0.18)(0.28) 0.29

(1.2) (3.2)(4.7) (11.2)
1.2
0.3

(7.4)
3.2
1.6

(1.3)
(1.3)
(1.6)

(5.4)
(5.1)
1.6

(6.2)
(0.7)
1.3

(4.5)
(1.1)
1.4

NORTH AMERICA
CanadaUnlted States(0.05) (0.08) (0.03) (0.02) (0.09)(0.04) (0.13) (0.03) (0.02) (0.08)

(1.5)
(1.5)

(1.0)
(1.0)

(0.8)
(0.8)

(3.0)
(3.0)

(0.7)
(0.7)

(2.0)
(2.0)

Numbers in parentheses are inferred values.

neat

Normallzed Integrated concentratlon(8q a/kg per keq/m2)
Graln
prod.

(2.5)
(5)

Leafy
veg.

Veg./
frult

neat

T a b l e

16Comparlson o f body burdens o f caeslum-137 d e r l v e d f r o m measurements I n man
and expected f r o m f o o d s t u f f c o n c e n t r a t l o n s
Ifl r s t - y e a r t n t a k e s )Country

Numberofpersons

Caeslum-137
deposltlon
denslty(k~s/m2)

Time-Integrated
body burdens (Bq a )MeasuredI n manAus t r l a
VlennaCountry average
BulgarlaCountry average

Expectedfrom d l e t

Bodyburdenratlo

Ref.

(measured/
expected)

1200
7000
9200

Czechoslovakia
Country average
Finland
Aeglon 1
Reglon 2
Reglon 3
Reglon 4
Aeglon 5
Country average
FranceReglon 1
Reglon 2
Reglon 3
German Dem. Rep.
Country average
Germany,
Fed. Rep. o f
Reglon 1
Reglons 2.3
HungaryCountry average
Italy
Reglon 1
Reglon 2
Japan
Country average
Netherlands
Country average
Norway0s l oOpplandN. Tr.
'
f lnmark
PolandCountry average
SwedenReglon 1
Country average

3000
61 0
1BOO
4600
10000
1 6000
4500
40
430
1700
1700
670
2600
39

3.1

770

2300

0.3

[H41

43
67

6
4

3500
2600

4200
31 00

0.8
0.8

[HbI
[M61

19

0.18

34

43

0.8

[N41

20

1.8

250

4 80

0.5

LC261

38
151
78 b/

1 .O
27.8
18.7
0.4

1400
31 00
21000
5600

5 50
15000
10000
21 0

2.5
0.2
2.1
27

r~lli

535

5.2

1700

31 00

0.6

[C21

50
218

31
6.8

1900
820

3300
1200

0.6
0.7

[FbI
[F61

2.0

7 50

1500

0.5

[PZI

30

4

1700

1900

0.9

[ 12 I

30
300

0.1
3

190
710

120
2500

1 .6
0.3

IF121
[f121

45

c/

Switzerland
Mltteland
TurkeyCountry average
U n l t e d Klngdom
Reglon 1
Reglon 3a/b//Measured cornposlted d l e t samples g l v e r e l a t l v e r e s u l t s o f 0.8 and 0.7
f o r r e g l o n s 2 and 3. r e s p e c t l v e l y [S21].
Southern Lapps.
N o r t h e r n Lapps.

[El 1I

[ell]

[Ell1

T a b l e

17First-year dose eaulvalents(uSv)

Thyrold
dose equlvalent

Effective
dose equivalent

Infants

Rural

Country

NORTH EUROPE
Denmark
Flnland
NorwaySwedenReglon 1
Reglon 2
Reglon 3
CENTRAL EUROPE
AustrlaCzechoslovakla
Reglon 1
Reglon 2
Reglon 3
German Oem. Rep.
Reglon 1
Reglon 2
Reglon 3
Germany. Fed. Rep.
Reglon 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Reglon 2
PolandRomanlaReglon 1
Reglon 2
Reglon 3
Swltzerland
Reglon 1
Reglon 2
Reglon 3
Reglon 4
WEST EUROPE
Belglum
FranceRegton 1
Reglon 2
Reglon 3
Ireland
Luxembourg
Netherlands
Unlted Klngdom
Reglon 1
Reglon 2
Reglon 3
SOUTH EUROPE
Bulgarla
Reglon 1
Region 2
GreeceReglon 1
Reglon 2
ltaly
Reglon 1
Reglon 2
PortugalSpa lnReglon 1
Reglon 2
Yugoslavia
Reglon 1
Reglon 2
Reglon 3

AdultsUrban

Thyrold
dose e q u l v a l e n t

Effectlve
dose e q u l v a l e n t

Infants

Adults

Rural

Urban

Reqlon 1
Reglon 2
Reglon 3
Regton 4
Reglon 5

21000
24000
3800
3600
82

6900
6300
1400
910
25

2000
930
4 60
140
4.3

1900
880
420
130
3.9

WEST ASIA
CyprusIsraelS y r l a n Arab Rep.
Turkey

4700
1500
1400
2300

1200
1100
74
4 80

67
94
7.7
200

66
92
7.3
180

75
110

11
I5

1.4
1.5

1.3
1.4

Country

USSR

EAST ASIA
Chlna
lndla
Japan
NORTH AMERICA
CanadaUntted States

T a b l e

18

C o u n t r y a v e r a a e o f f l r s t - y e a r dose e a u l v a l e n t s

Rat10 t o r e s u l t r e p o r t e dfrom country [NS]T h y r o l d dose
equivalentCountry

InfantAdult

Effectlve
dose
equlvalent

T h y r o l d dose
Effectlve
dose

(usv)
EUROPE
Bulgarla
AustrlaGreeceRomanlaFinland
Yugoslavla
Czechoslovakla
Italy
PolandSwl t z e r l a n d
Hungary
NorwayGerman Oem. Rep.
SwedenGermany. Fed. Rep
Ireland
Luxembourg
FranceNetherlands
Belglum
Denmark
U n l t e d Klndom
Spa 1nPortugal
USSR
ASIA
TurkeyIsraelCyprus
S y r l a n Arab Rep.
Chlna
Japan
Indla
NORTH AMERICA
CanadaUnlted States(usv)

InfantAdult

T a b l e

19

T r a n s f e r factor f r o m d e p o s l t l o n t o t h v r o l d d o s e f o r iodine-131

Country

NORTH E U R O P E
Denmark
Flnland
NorwaySuedenRegion 1
Region 2
Reglon 3
CENTRAL E U R O P E
AustrlaCzechoslovakia
Reglon 1
Reglon 2
Reglon 3
G e r m a n Dem.Rep.
Heglon 1
Region 2
Reglon 3
Germany.
fed. Rep. o f
Region 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Reglon 2
PolandRomanlaReglon 1
Reglon 2
Reglon 3
Sultzerland
Reglon 1
Reglon 2
Reglon 3
Reglon 4
WEST EUROPE
aelglumf rance
Reglon 1
Reglon 2
Reglon 3
Ireland
Luxembourg
Netherlands
United K i n g d o mReglon 1
Reglon 2
Reglon 3
SOUTH EUROPE
Bulgaria
Reglon 1
Reglon 2
GreeceReglon 1
Reglon 2
Italy
Reglon 1
Reglon 2
Portugal
Spaln
Reglon 1
Reglon 2
Yugoslavla
Reglon 1
Reglon 2
Reglon 3

Iodlne-131
deposltlon
densl ty(k8q/m2)

Thyrold d o s e equlvalentln flrst y e a r
f r o m lodlne-131( USV)

T r a n s f e r factor (P25)d e p o s l t l o n t o thyrold
d o s e f o r lodlne-131( u S v per k8q/m2)

Infartts

AdultsInfants

Adults

6.1
100
85

130
1500
930

33
690
350

21
15
11

5.4
6.7
4.1

160
13
41

1500
17
820

280
13
190

9.4
1.3
20

1.8
1 .O
4.6

Table 19, continued

Iodlne-131
deposltton
Country

Thyrold dose equlvalent
In first year
from lodlne-131(usv)

Transfer factor (P25)
deposltlon to thyrold
dose for lodlne-131(uSv per kBq/mZ)

Infants

AdultsInfants

Adults

590
480
160
20
0.4

20000
23000
3500
3600
80

5100
5500
980
790
22

34
48
22
180
200

2.0
0.7

4700
1500
1400
2200

1200
1000
69
320

2400
2100

600
1400

0.1
0.15

75
110

750
740

94
94

USSR
Reglon 1
Reglon 2
Reglon 3
Reglon 4
Reglon 5
WEST ASIA
CyprusIsraelSyrian Arab Rep.
Turkey

8.6
11

6.0
40
55

EAST ASIA
Chlna
Indta
Japan
NORTH AMERICA
CanadaUnl ted States

T a b l e

9.4
14

20

Transfer factor from deposltlon t o flrst-year effecttve dose equlvalentfrom lnqestlan of caeslum-137

Flrst-year dietCountry

Deposltlon
denslty

TEMPERATE
AustrlaBelglum
Bulgar la
Reglon 1
Reglon 2
CanadaCzechoslovakld
Reglon 1
Reglon 2
Reglon 3
FranceReglon 1
Reglon 2
Region 3
G e r ~ n0em.Rep.
Reglon 1,3
Reglon 2

Effective(k8q/m2)(Bqalkg)(Bq)

Body burden
Integrated
concentration(89 a/kg)

1.3
14.7
5.3

1.35
20.8
14.1

660
12100
7030

3.7
68
39

9.2
170
98

1.4

2.7

2.7
3.3
2.8

31
0.81
2.3

17.3
(6.3)
6.3

8860
(32101
3210

50
(18)
18

120
(45)
45

0.6
(7.7)
2.7

2.9
2.9
2.9

Integrated

Intakeconcentration

NORTH
Denmark
Flnland
NorwaySwedenReglon 1
Reglon 2
Reglon 3

Transfer factors

23
0.84
3.9
12
0.03
2.3
5.3
2.8
0.18
0.66
3.2
6.1
11

dose
equlvalent
(uSv)

bl

P34

P25,1

a/

-b/

c/

1.0

7.2
12
19
4.0
(55)
20

Table 20. contlnued

Flrst-year dlet
Country

Deposltlon
denslty

Integrated

Intakeconcentration(k8qlrn2)
Germany,
Fed. Rep. of
Region 1
Reglon 2
Reglon 3
Hungary
Reglon 1
Reglon 2
Ireland
Italy
Reglon 1
Reglon 2
Luxembourg
Netherlands
PolandRomanlaReglon 1
Reglon 2
Reglon 3
Sul tzerland
Region 1
Reglon 2
Reglon 3
Region 4
Unlted Klngdom
Reglon 1
Reglon 2
Region 3
USSR
Reglon 1
Reglon 2
Reglon 3
Region 4
Regton 5
Yugoslavla
Reglon 1
Region 2
Reglon 3

Transfer factors
Body burden
lntegrated
concentration(89 a/kg)

Effectivedose
equlvalent
(~SV)

bl

'34

'25.1

a/

b/

c/

(8q alkg)

(89)

2
4
16

4.5
8.2
31 .9

1690
31 00
12000

9.4
17
67

24
43
170

2.2
2.0
2.0

2.1
2.1
2.1

12
11
11

4.8
1 .5
3.4

13.0
8.9
8.4

7300
5000
3280

41
28
18

100
70
46

2.7
6.0
2.5

3.1
3.1
2.2

21
41
14

6
4
2.7
1.8
5.2

23.2
16.9
4.6
2.4
14.6

10700
7770
221 0
1 1 70
81 60

60
43
12
6.6
46

150
110
31
16
110

3.9
4.2
1.7
1.4
2.8

2.6
2.6
2.7
2.7
3.1

25
27
11
9.1
22

4.5
18
9

(10.3)(41 .O)
20.5(7250)(29000)
14500

(41)
(160)
81

(100)
(410)
200

(2.3)
(2.3)
2.3

4.0
4.0
4.0

(23)
(23)
23

14.8
3.5
2.0
1.3

59.1
10.0
6.1
3.7

37900
6430
3890
2390

210
36
22
13

530
90
54
33

4.0
2.9
3.0
2.9

3.6
3.6
3.6
3.6

36
26
27
26

0.1
1.7
3.0

0.69
7.9
14.2

300
3500
6300

1.7
20
35

4.3
49
88

6.9
4.7
4.7

2.5
2.5
2.5

43
29
29

38.8

14.5
10.0
2.8
0.094

73.7
21.2
18.3
4.2
(0.15)

50400
14500
12500
2890
(100)

280
81
70
1b
(0.6)

700
200
170
40
(1.4)

1.9
1.5
1.8
1.5
(1.6)

3.8
3.8
3.8
3.8
3.8

18
14
18
15
(15)

23
10
4

23.5
9.8
3.4

12400
5200
1780

70
29
10

170
73
25

1.0
1.0
0.8

3.0
3.0
3.0

7.6
7.3
6.2

SOUTH
Chlna
CyprusGreeceReglon 1
Reglon 2
Indla
IsraelJapan
Portugal
Spaln
Reglon 1
Fteglon 2
Syrlan Arab Rep.
TurkeyUnlted Staterg/ oeP0~iti0nto flrst-year total dlet; unlts: Bq a/kg per k~q/rn2.

b/ Diet to body; unlts: Bq a/kg per 8q a/kg.

r/ OePoSltlon to flrst-year comnttted effectlve dose rqulvalent; unlts: uSv per k8q/rn2

T a b l e

21Transfer factor from deposltlon t o effectlve dose equlvalentfrom inqestlon of caeslum-137 after t h e flrst year

Food consumption (kg/a)

Transfer factors

R e g l o n a/
Ullk
prod.

Graln
prod.

Leafy
veg.

Veg. /
fruit

Heat

Total

P 2 3 , 2 + b/------------Total
Graln
dlet

North Europe
Central E u r o p eWest Europe
Southeast Europe
Southwest Europe
USSR
W e s t Asla
E a s t Asia
North Amerlca

a/ N o r t h Europe: D e n m a r k , F i n l a n d , Norway. S w e d e n .
C e n t r a l Europe: A u s t r l a , C z e c h o s l o v a k l a , G e r m a n D e m o c r a t l c Republlc. Federal R e p u b l l c o fGermany. Hungary, Poland. Romania. Swl t z e r l a n d ,W e s t Europe: e e l g l u m , France, Ireland. Luxembourg, N e t h e r l a n d s , U n l t e d Klngdom.
S o u t h e a s t Europe: B u l g a r i a , G r e e c e , I t a l y , Yugoslavia.
S o u t h w e s t Europe: Portugal. Spain.
W e s t Asla: Cyprus. Israel. S y r i a n Arab Rep.. Turkey.
E a s t Asla: Chlna, Indla. Japan.
N o r t h Amerlca: Canada. U n l t e d States.
b/ D e p o s l t l o n to total d l e t a f t e r f l r s t year; unlts: Bq a/kg p e r k8q/m2.
c/ D l e t t o body; unlts: Bq a/kg p e r Bp a/kg.
d/ D e p o s l t l o n t o e f f e c t l v e d o s e e q u i v a l e n t c o m n l t n e n t a f t e r f l r s t y e a r ; unlts: u S v p e r k ~ q / m 2 .

T a b l e

22

Reqlonal transfer factors appllcable after flrst year
and c o m p o n e n t s of t h e e f f e c t l v e d o s e e q u l v a l e n t c o m n l t m e n t

ReglonPopulationwelghted
caeslum-137
deposltlon
denslty(k8q/m2)

T r a n s f e r factor r e l a t e d t ocaeslum-137 d e p o s l t l o n
P25,2+
External
gamna

E f f e c t l v e d o s e equivalentcornnl tment ( ~ S V )P25,2+ i n g e s t l o n

P25,2+

Cs-137

Total---------------Cs-134

flrst
year

After
f lrstyear

Total

North Europe
Central E u r o p eWest E u r o p e
S o u t h e a s t Europe
S o u t h w e s t Europe
USSR
W e s t Asla
E a s t Asia
N o r t h Arnerlca

a/ N o r t h Europe: Denmark. F l n l a n d , Norway. Sweden.
C e n t r a l Europe: Austrla. C z e c h o s l o v a k l a , G e r m a n D e m o c r a t l c R e p u b l l c . Federal R e p u b l l c ofGermany. Hungary, Poland. Romanla. Sultzerland.
W e s t Europe: Belglum. France. Ireland. Luxembourg. N e t h e r l a n d s . U n l t e d Klngdom.
S o u t h e a s t Europe: Bulgarla. Greece. Italy. Y ~ g o s l a v l a .
S o u t h w e s t Europe: P o r t u g a l , Spaln.
W e s t Asia: C y p r u s , Israel. S y r l a n A r a b Rep., Turkey.
East Asla: C h l n a , Indla, Japan.
North Amerlca: C a n a d a , U n l t e d States.

T a b l e

23

T o t a l t r a n s f e r f a c t o r f o r effective dose e a u l v a l e n t
based on caeslurn-137 d e o o s l t l o n[ uSv per k8a/m2)

North
Pathway/
radlonucl lde

Temperate

South

flrst
year

After
flrst
year

Total

first
year

After
flrst
year

Total

Flrst
year

2.2
2.5
5.6

71
4.9
0.2

73
7
b

2.2
2.5
5.6

71
4.9
0.2

73
7
6

2.2
2.5
5.6

71
0.2

73
7
b

10

76

86

10

76

86

10

76

86

Cs-137
Cs-134
1-131

15
11
1

20
12

35
23

20
12

-

40
26
10

25
18
20

25
15

1

20
14
10

-

50
33
20

Subtotal

27

32

59

44

32

16

63

40

103

40

110

150

50

110

160

70

120

190

External gama
CS-137
Cs-134
Other
Subtotal

After
flrst
year

4.9

Total

Ingestion

T o t a l (rounded)Total caeslum-131 deposlt and dose comltnwnts tn the northern henlsphere

Effective dose eaulvalent comnltmcnt
Cs-137
deposit

Per caput (US,)

Coilectlve (man Sv)

Populatlon(Pea)

First year

Total

flrst year

8.2
7 .O
1.3
8.2
0.03

7 .O
6.0
1 .0
7.2
0.03

10.2
8.8
1.2
6.8
0.02

210
280
48
380
4

970
930
150
1200
7

4100
49000
6600
39000
180

1.4

5.0

30.9

260

810

72000

226000

2200
5400
7800
6600

1.0
0.08
0.03
0.04

1 .O
0.08
0.03
0.04

4.6
0.5
0.08
0.5

70
6
2
3

190
IS
6
8

8000
6100
510
3600

22000
16000
1400
9600

347.0
30.1
26.9
49.7

9000
9200
10700
10100

0.02
0.018
0.012
0.013

0.02
0.018
0.012
0.013

0.4
0.004
0.006
G.03

1
1
0.7
1

4
3
2
2

490
40
20
50

1300
100
60
120

8438
6118
2415
2117

128.4
172.3
16.3
59.5

3000
5600
5300
51 00

0.4
0.08
0.08
0.09

0.4
0.08
0.08
0.09

3.4
0.5
0.2
0.2

28
6
5
6

76
15
15
17

3600
970
100
380

9800
2600
280
1000

Greenland
North Atlantlc Ocean
North Paclf lc Ocean

2176
53000
102000

0.06

4000
5700
1 0900

C. 18

0.18

0.4
3.7
1 .O

7

30

Northern hemisphere
Total (rounded)

252800

5700

0.3

0.9

70

45

140

Area

Populatlon

Olstancefrom
Chernobyl(103km2)

(106)

(km)

Area

EUROPEa/
North
b/
Centralc/uestSoutheast
Southwest e/

1249
1253
936
829
596

22.8
178.0
137.7
101 .b
47.2

1300
1200
2000
1500
2900

USSR

22190

279.1

ASIA
Southwest f /91
SouthSoutheast h
East

4611
6786
2575
11720

114.9
1082
240.6
1268

AMERICA
horth
11
Carlbbean k/
1/
Central
South
!/

20560
21 6
51 7
2520

AFRICANorth
west
Central
East

i/

-n/
o/
e/
91

4304

Caeslum-131 deposltlon(k6q/m2) uelghied b y

C.07
6.01

0.4

200000

Total

22000
1 66000

21000
121 000
340

2

600000-a/ Denmark. Flnland. Iceland, Norway. Sweden.
-b/ Austrla. Czechoslovakla. Germn 0em.Rep.. Germany. fed.Rep.. Hungary. Poland. Romanla. Switzerland.
-C/ Belglum. France. Ireland. Luxecnbourg. Netherlands. Unlted Klngdom.
d/ Albanla. Bulgaria, Greece. Italy. Malta. Yugoslavla.

g/ Portugal. Spaln.
-f/ Bahraln. Cyprus. Oem. Yemen. Iraq, Israel. Jordan. Kuualt. Lebanon. Oman, Qatar. Saudl Arabla. Syrlan Arab Rep., Turkey.
Unlted Arab Emirates. Yemen.
q/ Afghanistan. Bangladesh. Bhutan. Indla. Iran. Nepal. Paklstan. Srl Lanka.
h/ Burma. Dm. Kampuchea, Laos Oem. Rep.. Malaysia. Phlllpplnes. Slngapore, Thatland. Vlet Nam.
l/ Chlna. Oem. Korea. Hong tong. Japan. Korea, Rep.. Mongolla.
Canada. Unlted States. Mexlco.
k/ Cuba. Oomlnlcan Rep.. Haltl. Jamalca. Puerto Rlco. Trlnldad/Tobago.
1/ Costa Rlca. E l Salvador. Guatemala. Honduras. Nlcaragua. Panama.
Coloinbla. Guyana. Surlnalae. Venezuela. French Gulana.
n/ Algerla. Egypt. Llbya. Morocco, Sudan. Tunlsla.
O/ Benln. Burklna Faso. Cape Verde, Cote d'lvolre. Gambla. Ghana. Gulnea. Gulnea-Blssau. Llberla. Mall, Maurltanla. Niger.
Hlgerla, Senegal. Slerra Leone, Togo.
p/ Cameroon, Central Afr.Rep., Chad. tpuatorlal Gulnea.
Q / Ethlopla, Socaalla. Uganda. DJlboutt.

I/b/

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