General Situation of the Radiological Consequences of the Chernobyl
Accident in Ukraine
Dmytro M. GRODZINSKY
Institute of Cell Biology and Genetic Engineering, National Academy of Sciences of Ukraine
148 Zabolotnogo St., Kiev, GSP-22, Ukraine
fax: +044 267 1050, e-mail: phyto@rbio.isf.kiev.ua
and south-west plumes. Much more than 2*1018 Bq ofradionuclides were released from this unit anddispersed over wide areas (1).
The scale of radionuclide contamination of theterritories is very significant. As we have shown, thearea highly contaminated with 137Cs in Ukraine
occupies a space over 37 thousand sq. km. In
consequence of the radionuclide contamination
Ukraine lost tens of thousands sq. km of forest andarable land.
The surface contamination is extremely spotty.
Spots of radioactive contamination have been formed
after the trace of the plumes on very large territories.
At the present time, we know well the spatial
distribution of radioactivity in Ukraine. The spots
differ in sizes having diameters from few meters tohundreds of km.
The population inhabiting the contaminatedterritories in Ukraine is as follows (1, 3):

Introduction
April 26, 1986, will go into history as the date whenthe 4th reactor of the Chernobyl Nuclear Power Station
exploded causing radioactive contamination of a wide
area practically in all Europe. The initial explosions
and heat carried volatile radioactive materials up to 1.5
km height from where these materials were transported
over large territories. Plumes containing numerous
quantities of radionuclides moved with prevailingwinds to the north, east, south and west, precipitating
radioactive particles on areas thousands of miles away.
Regions affected with the radionuclides from the
Chernobyl's wrecked reactor included not only
Ukraine itself but also Belarus, Russia, Poland,
Sweden, Norway, Finland, Germany, Hungary,
Slovenia, Lithuania, Greece, Bulgaria, Slovakia andmany others. The volatile radioiodine, otherradionuclides and small hot particles were detected inthese countries on the very first days after the
Accident. Crops, vegetables, grasses, fruits, milk, dairy
products, meat and even eggs were sometimes so
contaminated with radionuclides that they had to beabandoned.
The total amount of radioactivity released exceeded
significantly 50 Mega Curies. On the roof of thedestroyed reactor building, dose rate in May-June 1986
reached a very high level of 100,000 Roentgens perhour (1).
The main dose load on the Ukrainian population iscaused by radionuclide contamination of the country
territories located outside the alienated zone following
the Chernobyl accident.
The territories contaminated with radionuclide137
Cs in Ukraine are as follows (2,3):
Levels of surface
contamination,
Ci/km2
5-15
15-40
above 40
Total

Levels of surface
contamination,
Ci/km2
1-5
5-15
15-40
above 40
Total

Population, thousands ofpeople1,227.3
204.2329.7
19.2
1,480.4

The radionuclide contamination of the areas
marked the beginning of a series of very dangerous
radiological and radioecological consequences on alarge scale and for a long time.
Ecological and radioecological consequences,economic burden, political pressure and speculation
prevailing among politicians, and large moral andpsychological symptoms affecting the Ukrainian
population are linked together by that heavy chain
which the Chernobyl accident had brought in Ukraine
eleven years ago.

Contaminated territories
space, km2
2,355
740
680
3,775

Radioecological Consequences
This main radioecological consequences of theChernobyl accident are as follows:
1. The large activity of fission products escaped into
the atmosphere and further into ecosystems. The
radionuclides are migrating through all componentsof the ecosystems in the landscapes and, as a result,alllivingbeingsbecameradioactive;

Clearly the territory of agricultural use with a level ofthe surface contamination of an order of 1-5 Ci/km2 ismuch more - 33,160 square km.
The radioactive materials from the reactor had been
deposited along the north, west, east, south, south-east

18

microorganisms, mushrooms, plants, insects, otheranimals and human beings.
2. Radioactivity is moving to ground water andcontaminating surface water.
3. Radionuclides come to the trophic chains and are
moving to people. All things around people becomeradioactive as well as the bodies of adults andchildren. For one example, the radioactivity ofleaves of some trees in the central Kiev’s streets in1986 varied from 70,000 to 400,000 Bq/kg (1, 4).
4. Dispersed radionuclides migrate in the biosphereand this process is accompanied by shaping of doseload on all living beings, including a large number of
population. Exposure of population due to the fallout
from the Chernobyl reactor accident occurs via threepathways: external irradiation from radioactive
materials deposited on the ground, inhalation of
airborne material, and ingestion of contaminatedfoodstuff. The contribution of ingestion ofcontaminated foods to the total irradiation dose isvery high. It is worthy to note that internal irradiationis characterized by its much more higher biologicaleffectiveness than external irradiation.
5. Excess of irradiation over the natural background
could lead to manifestations of different kinds ofdiseases in people and deterioration in flora andfauna on the territories contaminated withradionuclides.
Plants being cultivated on soil contaminated withradionuclides uptake these radionuclides in proportion
to their concentrations in soil solution and to biologicalsignificance of corresponding carriers. An example ofradionuclide activity in sod-podzolic soil and someplants is shown in Table 1.
As evident from the data of Table 1, the uptake rateof radionuclides varies considerably depending onplant species. The radionuclide accumulation differs
not only by the species of plants, but also significantly
by the varieties within the same species. For varieties
of winter rye, for example, the values of specificactivity of dry masses varies from 14,900 to 1,100
Bq/kg for 137Cs.
The coefficient of radionuclide accumulation byplants (CA) has been intensively investigated lastyears. Attention is drown to the fact that the values ofthese coefficients are very variable being dependent onplants, physical-chemical state of radionuclides andtheir carriers in soil (1).
 s p c ific a c tiv ity o f d ry p la n t m a s s 
fo r a c e ita in ra d io n u c lid e

CA 


s p e c ific a c tiv ity o f s o il

depends also on soil acidity. Typical values of CA forpea, corn, winter wheat, barley, sugar beet and cabbage
range from 0.06 to 0.30.
The CA coefficients are much higher insalt-tolerant plants. This is apparent from Table 2.
The total reserves of radionuclides in different
components of ecosystems and the rates of transfer ofradionuclides to the food-stuffs (mainly milk, meat,
mushrooms, fishes ) set the extent of exposure ofpeople to irradiation.
A very dangerous place within the 30 km zone
around the destroyed reactor is the “Sarcophagus”

Table 1 Contents of radionuclides in soil and plants grown in the vicinity of the wrecked Reactor. July
1987 (4)Activity, Bq/kg of dry weight
Object
137
144
106
95
Cs
Ce
Ru
Zr/95Nb
Soil
51,800296,000
92,20040,700Vetch
71,78017,4303,700
410
Clover
45,50090,3008,000
14,360Melilo
9,770
9,200
1,400
1,400
Pea
4,400
1,500
330
150
Lupine4,100
10,7005,550
1,440
Alfalfa
1,800
2,150
1,400
70
Oats
330
520
150
75
Barley
260
330
40
40
Table 2 Coefficients of 90Sr accumulation (CA) in some salt-tolerant plants (4)Plant species
CA
Chenopodiacea
Climacoptera salsa
2.38
Kochia scoparia
1.59
Kochia prostrata
2.03
Atriplex Fominii
1.59
Atriplex acuminata
1.06
Petrosimonia crassifolia
2.80
Salicornia europaea
1.70
19

protectively entombing the fourth unit. This
entombment covers the monstrous ruin and radioactive
remains spewed from the reactor core. The
Sarcophagus remains a hazardous building because it
contains about 200 tones of the fuel materials in theform of solidified lava with very high levels ofradioactivity. In the contemporary state, thefuel-containing materials are sub-critical. But ingressof water into the Sarcophagus, earthquake, alterationof the Sarcophagus construction can change thesub-critical state of fuel into critical. The fate of theSarcophagus as well as the fate of sedimentation inponds and rivers within the contaminated region, andthe radioactivity of the “Red Forest” which had died asa result of accumulation of large radioactivity are now
hard to be forecast.

Thirdly, the real levels of irradiation dose to people
were much higher than we believed in the first years
after the Catastrophe.
In such a situation we have no basis to apply the
traditional radiological knowledge to elucidating,quantitatively evaluating and predicting the real threatof the Chernobyl radionuclide contamination.
The population living on the contaminatedterritories (above 0.5 Ci/km2) exceeds five millions
people. The victims of the Catastrophe can be logicallyclassified into six groups according to conditions ofirradiation. These groups are as follows:
1. people who took part in overcoming the accident
consequences within the territory where the wrecked
reactor is located. This territory represents a roundarea ringing the reactor. The radius of this area isequal to 30 km. It is named as the 30-km Zone or
Alienation Zone. People having worked in this Zone
are named Liquidators;
2. people evacuated from Prypyat’ city and othersettlements located within the 30-km Zone;
3. people evacuated from the territories contaminatedwith very high radioactivity;
4. people living on the highly contaminated territories;
5. children who had received high doses on thyroid
gland from radioactive iodine;
6. children from irradiated parents.
I would like to show a sketchy description of themain factors of the radiological effects being formed in
the territories contaminated with radionuclides.
Two general types of radiological effects arerecognized: non-stochastic and stochastic effects.
Non-stochastic effects consist of somatic damages
and deficiencies of the immune system. These effects
induce the secondary diseases which can be manifested
as illnesses mainly non-specific for radiation. At thesame time, acute radiation sickness refers also to
non-stochastic effects of irradiation. Manifestation ofthese effects depends on dose, dose-rate, types ofradiation and the relationship between external andinternal irradiation.
Stochastic effects are characterized by probabilistic
nature of its manifestation. Cancernogenesis based oncell transformations, mutagenesis of somatic orgametes cells refer to stochastic effects of irradiation.
What is known at the present time about revealingof these effects in people?
It is very sad, but the state of people's health has
been affected to a great extent during ten years after the
Accident.
The main information basis to evaluate health ofthe people suffering from the Chernobyl Catastrophe is
the National Register of victims. As for January 1995,
the National Register in Ukraine included 432,543
persons. The Military Medical Register of the Ministryof Internal Affairs of Ukraine includes nearly 36,000
persons.

Assessment of Radiological Consequences
Since the very beginning of the accident, theinformation about the scale of the disaster has been
misjudged and misleading. Even today the world
opinion is far from truly elucidating the real scope of
the impact of the Catastrophe on mankind. A sharply
outlined controversy among specialists in the field ofradiology exist till now about the medical
consequences of the Chernobyl accident. Opinions
differ as to the real causes of the increasing numerous
diseases in the Ukrainian population after the
Chernobyl accident. There are many supporters of a
speculation that the morbidity augmentation after the
Accident is due to psychological factors and no other.
The term “radiophobia” was embedded in radiologicalliterature. However, there is also a speculation that themorbidity is deeply allied to the radionuclide
contamination in the environment. There are reliabledata about the effects of low dose of irradiation and thehealth consequences of iodine influence on thyroid
gland.
I would like to note that there are disgraceful andinhumane attempts to mendaciously diminish theconsequences of the Chernobyl accident or even treat it
as a thing of the past to be forgotten and erased frommemory. This point of view come up mainly fromprejudiced supporters of atomic energy, dignity ofwhich has been suffering from the accident at the
Chernobyl Nuclear Power Station. I believe, however,that this accident should not be forgotten. On thecontrary, we should be very attentive to revealing of
the consequences of the Accident because it is related
to principally new aspects of radiation accidents
ecologically dangerous in a large scale as follows.
Firstly, the conditions of combined irradiation by
mixture of beta-, gamma- and alpha- rays are of rather
high radiological effectiveness.
Secondly, the scope of people exposed to the actionof ionizing radiation is unprecedentedly numerous.

20

Table 3 Birth-rate and mortality after the Chernobyl accident in Ukraine(cases on one thousand of residents)
Natural alteration ofYear
Birth-rate
Mortality
population
1990
12.7
12.1
0.6
1991
12.1
12.9
-0.8
1992
11.4
13.4
-2.0
1993
10.7
14.2
-3.5
1994
10.0
14.7
-4.7
1995
9.6
15.4
-5.8
Data of the Health Ministry of Ukraine, September 1996.
Table 4 Infantile mortality after the Chernobyl accident in Ukraine
Year
Number of cases in country Number of cases per 1,000
1990
8,525
12.84
1991
8,831
13.90
1992
8,429
13.98
1993
8,431
14.93
1994
7,683
14.54
1995
7,314
14.68
Table 5 The main causes of infantile mortality in 1990-1995
Diseases
Number of cases per 10,000
Pathological states arisen during
48.4
prenatal period
Inherent anomalies
42.6
Diseases of respiratory system
14.5
Infectious and parasitic diseases
11.2
Altogether over 3,200,000 people in Ukraine areconsidered to be ill owing to the Chernobyl
Catastrophe. Almost 1,000,000 of them are children(5). A brief mention should be made on the health stateof the people in Ukraine which has been heavily
deteriorating last years. It can be seen from the next
Tables (6).
From Table 3 we notice that the mortality rate
exceeds the birth rate in Ukraine from 1991. The paceof the increase in infantile mortality is very high lastyears (Table 4). The main causes of the infantile
mortality are identical to that for the population
affected by the Chernobyl accident (Table 5).
Mortality in the able-bodied residents in Ukraine has
increased sufficiently last years particularly in men(Table 6).
Epidemiological investigations of the influence of
the Chernobyl accident should be carried out with due
regard for total deterioration of the state of health as awhole in Ukraine.
After the Chernobyl accident an annual increase of
sickness incidence among the victims has beenregistered (5).
The alterations of a very general index of the stateof people's health, namely percentage of practically
healthy people, testify that there exists a sharp
deterioration in the health state of adults, adolescentsand children of the affected population (Table 7).

Weight, %
33.0
29.0
9.9
7.6

The percentage of healthy people decreases
drastically with time in three groups of the Chernobyl’svictims. Since 1987 the percentage of healthy
population decreased from 80 % to 20 % andsometimes less. To site one example, in the
Dubrowitzki district of the Riwno region there havebeen no healthy children last years. The high level ofinternal irradiation was observed in this place.

Health state of the participants of the liquidationof the Chernobyl accident consequences and of
the people evacuated from the 30-km Zone (zoneof alienation)
Territory of Ukraine was divided into zones
depending on levels of radionuclide contamination insoil and values of average effective dose (1). There are
the next four zones:- Zone of alienation: the 30-km Zone around theChernobyl Nuclear Power Station;- Zone of obligatory settling out: level of a surface
density of contamination with 137Cs above 15
Ci/km2, with 90Sr above 3 Ci/km2 or Pu above 0.1
Ci/km2. In addition, the territories covered with thesoils in which intensive migration of radionuclides
occurs with a surface density of 137Cs
contamination of 5 - 15 Ci/km2, with 90Sr of 0.15 - 3
Ci/km2, or Pu from 0.01 to 0.1 Ci/km2 are also
included in this category. The effective equivalentdose stands out above 5 mSv /yr.
21

Table 6 Mortality in the able-bodied residents (Number of cases on 100,000)
Year
1990
1992
1994
1995
All causes of death:
Men
697.7
826.9
942.8
1055.1
Women
199.3
216.9
234.7
256.8
Tumor:
Men
226.5
279.9
312.0
349.7
Women
41.2
49.3
54.1
60.2
Diseases of blood circulation:
Men
202.1
242.0
286.4
322.2
Women
50.4
54.1
60.2
65.9
Table 7 The index of practically healthy people , %The groups of victims
Evacuees fromYear
Liquidators
30-km Zone
1987
82
59
1988
73
48
1989
66
38
1990
58
29
1991
43
25
1992
34
20
1993
25
16
1994
19
18
- Zone with the right for settling out: territories
contaminated with 137Cs in the range from 5 to 15
Ci/km2, 90Sr in the range from 0.15 to 3 Ci/km2 or
Pu in the range from 0.01 to 0.1 Ci/km2. When thesoils on territories are characterized by intensive
uptake of radionuclides, the limits of the surface
density are as follows: 137Cs of 1 - 5 Ci/km2; 90 Sr of
0.02 - 0.15 Ci/km2 or Pu of 0.005 - 0.01 Ci/km2.
The effective equivalent dose should not exceed 1
mSv/yr over the pre-accident level of irradiation.
- Zone of residing with strict radiation control:
territories contaminated with 137Cs in the range
from 1 to 5 Ci/km2, 90Sr from 0.02 to 0.15 Ci/km2 or
Pu from 0.005 to 0.01 Ci/km2. When the soils on
this territory are characterized by intensive uptake
and migration of radionuclides, the limit of thesurface density is 137Cs of 0.2 - 1 Ci/km2. The
effective equivalent dose should not exceed 1
mSv/yr.
The victims of the Chernobyl accident in official
documents are divided into four groups in thefollowing way:
- The first group encloses the participants in theliquidationoftheChernobyl
accident
consequences. 245,587 persons fall in this group.
Amongst this group, there are 223,908 men and21,679 women.
- The second group embraces the people evacuatedfrom the Zone of alienation and emigrants from theIncrease compared
to 1990, %
+51.2
+28.9
+54.4
+46.1
+59.4
+30.1

Children from
irradiated parents
86
78
72
62
53
45
38
26

Zone of obligatory settling out. This group consistsof 70,483 persons, among which there are 31,365
men and 39,128 women.
- The third group covers the residents who are living
now or were living some years after the Accident in
the Zone with strict radiation control. This group isvery numerous, it consists of 2,096,000 persons(45.7% men and 54.3% women).
- The fourth group encompasses the children born fromthe parents of any one of the listed groups. This
group consisted of more than 317,000 children in
1995.
The epidemiological data testify that the morbidityof the victims of the Chernobyl accident as a whole andby main classes of diseases is higher than the averagevalues in Ukraine and has a very clearly defined
tendency of increasing with time (7, 8 ). It can be seenfrom Table 8 that the index of morbidity is drasticallygrown with time. The data of morbidity about maindiseases are shown in Table 9.
The number of patients among the participants of
the liquidation of the Chernobyl accident
consequences increased by 2.7 times in relation to
1987. Among the children of the fourth group,morbidity has been increased by 2.5 times last years.
The number of patients increased by 56.3 % in the thirdgroup and by 33.6 % among people related to thesecond group.

22

Table 8

Index of morbidity of the victims by the Chernobyl accident (per 10,000)
Groups of the victims
Year
Adults and adolescentsChildren (less than 14 yr)
1987
4,210
7,866
1994
12,55916,026

Table 9Index of morbidity in adults and adolescents of the suffering people (per 10,000)
Year
Nosological forms
Mean in population
1987
1996
Diseases of blood and hemopoetic system
12.7
30.5
12.6
Diseases of endocrinologic system
41.1
70.0
41.6
Neoplasia of the lymphatic and hemopoetic
3.0
6.7
systemTable 10 Structure of morbidity in adults and adolescents of the victims in 1994
Nosological form%
Diseases of respiration system
35.6
Diseases of nervous system
10.1
Diseases of blood circulation system
8.6
Diseases of digestion system
6.4
Diseases of osseous-muscular system
6.4
Genito-urinary diseases
6.1
Table 11 Index of morbidity in people living in territories of strict radiation control.
(Data of 1996, per 10,000)
Nosological form
Victims
Mean for population of Ukraine
Diseases of hemopoetic system
30.2
12.6
Diseases of blood circulation system
430.4
294.0
Diseases of endocrinologic system
54.2
37.8
Diseases of digestion system
280.9
210.1
Diseases of osseous-muscular system
333.0
307.1
Table 12

Index of mortality in the groups of the victims in 1996
Groups of victims

Participants of the liquidation of the Chernobyl accident consequences
People evacuated from the Zone of alienation
Residents in the territories of strict radiological control
Able-bodied population in Ukraine
Mean for population of Ukraine

The structure of morbidity is specific for thevictims of the Chernobyl accident. The pattern of thenosological forms is shown in Table 10. Diseases ofblood and hemopoetic organs increased during lasteight years by 3.9 times.
Morbidity in people living in the territories
contaminated with radionuclides is well above themorbidity in the average in population of Ukraine. It isseen from the data of Table 11.
The mortality of adults and adolescents subjected toradiation exposure due to the Chernobyl accident
essentially increased after 1987. It can be seen from
Table 12.
The structure of the death causes of the Chernobyl
victims is as follows:

Index (per 1,000)
9.06
11.60
18.42
6.50
15.20

- diseases of blood circulation system; 61.2 %,- neoplasm; 13.2 %,(incidence of death from malignant tumors in thesecase ranges up 98 .4 %);- traumatism; 9.3 %,- diseases of respiration organs; 6.7 %,- diseases of digestion organs; 2.2 %.
The primary disablement in the suffering people
has drastically increased last years. It can be seen from
Table 13.
The data on the health state of the people who
suffered from excess of irradiation confirm beyond any
possible doubt that the environmental situation in thenorth part of Ukraine is unfavorable and inauspicious
for people life.

23

Mortality of children of 0 -14 years increased from
0.5 per 1000 in 1987 to 1.2 in 1994.
The children mortality increases at the expense of
diseases of the nervous system and sense organs(augmentation by 5 times), congenital defects(increasing by 2.4 times) along with the infectious andparasitic diseases, and the diseases of blood circulation
system.
Dynamics of the mortality by malignant tumors ofvarious localization has no regular trend, but the levelof oncological mortality of the suffering children ishigher than this form mortality of the inhabitants inanother parts of Ukraine.

Health state of children subjected to radiation
exposure due to the Chernobyl accident
Increase of primary and total morbidity of children
subjected to radiation exposure due to the Chernobyl
accident was registered on the majority of diseaseclasses for the period 1987 - 1996, as well as constantaugmentation of the number of children with chronic
pathologies. Table 14 gives the value of morbidity andprevalence of diseases in children of the regions
affected by the Chernobyl accident.
It follows that the prevalence of diseases increased
for 10 years by 2.1 times and the rate of morbidity
increased by 2.5 times. It should be pointed out that thehighest level of morbidity increase is registered forneoplasm, congenital defects and diseases of blood andhemopoetic organs. The highest level of morbidity isinherent to the children of the third group of victims(residents of the zone with strict radiation control). It
should be mentioned that the morbidity of children in
all Ukraine decreased by 20.8 % for the same period.
Thus, the morbidity of the suffering children
exceeds significantly the all-Ukrainian level ofchildren morbidity (7, 8 ). The structure of morbidity isshown in Table 15.
Morbidity of the suffering children by malignant
tumors has noticeably increased as compared with theindex of oncological morbidity of children in anotherparts of Ukraine. Oncological morbidity of children in
the affected zones increased for ten years after 1987 by
3.6 times.
The rate of congenital defects increased for thesame period by 5.7 times and morbidity of children by
diseases of blood circulation system and hemopoetic
organs increased by 5.4 times.
Along with the increase of the pregnancy pathology
and confinement, there increases new born children
mortality.

Malignant thyroid tumor
It is now indisputable that the Chernobyl accident
has influenced the increase of thyroid gland tumor
morbidity. It is established that the growth ofmalignant thyroid tumor is connected withradionuclides of iodine released during the Accident
from the damaged reactor unit. Before the Accident
thyroid cancer was rare and characteristic mainly for
elderly people. In children and adolescents anestimated annual incidence of thyroid cancer wasaround 0.2 to 0.4 cases per million children,
representing around 3 % of all tumors. In 1981 -1985
there were only 25 cases of thyroid cancer in children
in Ukraine.
The latency period between irradiation and cancer
development varies with an average period around
8-10 years. There is no correlation between radiationdose and the length of the latency period. However, theincrease of thyroid cancer morbidity began well before
the time it was predicted, namely, after 4 years fromthe Accident and is continuing up to now.
The risk of thyroid cancer has sharply increased
within the children subjected to irradiation at the age
under 3 years old at the moment of the Accident. A

Table 13 Index of the primary disablement (per 10,000)
Groups of people
Year
Participants of the liquidation of the People evacuated from the
Chernobyl accident consequences
Zone of alienation
1987
9.6
20.5
1994
232.4
95.2

Other
5.4
9.3

Table 14 Index of morbidity and prevalence of diseases in children of the affected regions(per 1,000)
Year
Index of morbidity
Index of prevalence of diseases
1987
455.4
786.6
1994
1138.51651.9
Table 15 Structure of morbidity of children of the suffered regions
Nosological forms%
Diseases of respiration system
61.6
Diseases of nervous system
6.2
Diseases of digestion system
5.7
Diseases of blood and hemopoetic system
3.5
Diseases of endocrinologic system
1.2
24

characteristic feature is a high aggressiveness of
thyroid cancer. In a half of cases the tumor goesoutside of thyroid gland and grows into surrounding
tissue and organs.
Number of the cases of childhood thyroid cancer isseen from the data of Table 16 (9).
The majority of cases of children thyroid
carcinoma, 94 % are papillary forms.
It seems reasonable to say that the tendency toaugmentation of manifestation of this cancer inchildren will continue many years. It appears this formof cancer did not peak yet.

The results of radiobiological investigations carriedout in the contaminated territories near the Chernobyl
Nuclear Power Station have shown last time very
important new facts.
The most important radiobiological effects related
to irradiation at low doses have been revealed in thefollowing:
1. Significant non-linearity in dose-dependent curvesof radiobiological effects of irradiation at low doses.
2. Induction of genome instability under the influenceof irradiation at low doses has come to light based on
the chromatographic pattern of restricted DNA
which has been studied in the experiments on
different plant species growing in the soil
contaminated with radionuclides.
3. Disruption of the position control owing toalteration of repeated sequences of DNA molecules
is considered as a likely target at low doses.
4. Deterioration of the accuracy of DNA repair withincells. In our studies to date, by measuring
unscheduled DNA synthesis, we have observed acomplete failure of DNA repair in birch pollen in thefirst generation of pollen after the Chernobyl
accident. Inhibition of unscheduled DNA synthesisin the next generation of birch pollen from the samesite was less. However, later pollen from Chernobyl
failed to achieve proper DNA repair, suggesting thata hidden damage still persisted in the overallmechanisms for DNA repair after chronic irradiation
at low dose rates.
The data of these experiments are presented inTable 17. It is clear that the genotoxicity of irradiationfrom a mixture of radionuclides is much higher thansimilar doses from external gamma-irradiation only.
It was shown that the stochastic effects, likemutagenesis, was closely related to internal irradiationfrom accumulated radionuclides in cells. In this casethe relative biological effectiveness of internal
irradiation was much greater than under external
irradiation. The waxy-mutation of barley and tests forpigment-mutants formation were used in theseexperiments under the controlled level of prolonged
mutagenesis (12).
It is apparent that mutagenic effects in plant cells,in the case of radionuclide contamination of soil, couldRadiobiological appraisal of the radiologicalconsequences
The real reasons responsible for the worsening of
population health in Ukraine can be recognized fromthe radiobiological research carried out on the
biological test-systems of different kinds. We usedplant-systems to reveal the role of chronic irradiation
at low doses on forming the stochastic andnon-stochastic effects. Experiments have been carriedout under the controlled conditions in the area
influenced by the Chernobyl’s radionuclides fallout.
The intimate linkage between the rate of the mitotic
crossingover and irradiation has been proved in the
mutant system of special plants. DNA repair processes
in pollen cells were initially blocked or seriously
reduced in accordance with the level of irradiation at
Chernobyl (10). The present generations of pollen
from trees exposed to continuous irradiation at
Chernobyl fail to repair with fidelity the genesequences in a series of experiments so far carried out.
Epigenetic imprinting during morphogenesis showed ahigh sensitivity to internal irradiation and the hotparticles located on the meristematic tissue (11).
Alterations of mobility of some restriction fragmentsof DNA after chronic irradiation of cells bear witness
to the significance of irradiation at low doses forstability of genom of somatic cells.
The results of fundamental radiobiological researchshould be considered in the attempts to understand themechanism of the changes occurring in irradiated cells
and of the augmentation of numerous diseases owing
to the Chernobyl accident.

Table 16 Number of cases of thyroid cancer in children in Ukraine after the Chernobyl accident (forcontingent with age from 0 to 19 years when the accident occurred)
Year
Number of Cases
Cases per 100,000
1986
15
0.12
1987
18
0.14
1988
22
0.17
1989
36
0.28
1990
59
0.45
1991
61
0.47
1992
108
0.83
1993
113
0.87
1994
134
1.00
1995
166
1.30
25

not be extrapolated on the basis of measured dose. The
yield of chromosome aberration is very high underchronic irradiation at low doses. This is supported byexperimental results presented in Table 18.
The frequency of chlorophyll mutation is also
increased by irradiation due to radionuclide
contamination. The results of experiments on rye aretabulated in Table 19.
The data discussed above point to the conclusionthat irradiation at low dose due to radionuclides
incorporated by tissue is followed by strong genetic
effects. It might be well to point out that themechanisms of radiation mutagenesis and celltransformation are identical both for plant and animalcells. There is no question that irradiation owing its
origin to radionuclides accumulated within cells isdistinguished for its high biological effectiveness. The
use of plant test systems which are capable of fast
responding to irradiation at low dose holds beyond any
reasonable doubt a great promise for the assessment ofradiological risk.

affected by radionuclide contamination in theenvironment. This deterioration of population healthembraces a broad spectrum of diseases.
Social psychological consequences of the Accident
are also very impressive. Under the influence of what
people has seen and heard from the first years after the
Accident, the confidence in many things has beensometimes completely lost for a long time. But there isa tendency to consider the morbidity augmentation
exclusively as a result having been associated withfactors of non-radioactive origin (chemicalcompounds,
heavy
metalsandmainlysocial-psychological syndrome development).
I should note that some specialists being mainly
under ascendancy of the Nuclear Energy Authorities
try to prove from the first days after the Accident thatall deterioration in the health state of the people livingon the territories contaminated with radionuclides aswell as of Liquidators are not directly related to theimpact of irradiation. Why are such doubts being castupon existence of the relationship between irradiationand frequency of diseases in the victims of theChernobyl catastrophe? Skeptics say that there are no
reliable and sufficient proofs of these relationships.
The evidences for this thinking are the following:

Discussion
Following the Chernobyl Nuclear Accident on
April 26,1986, epidemiological analyses of data point
to impressive deterioration of health of the people

Table 17 Frequencies of waxy reversion in barley pollen as a result of 55 days of exposure to various
levels of radionuclides released at Chernobyl and a pure gamma-field
Total reversion
Dose rate (µSv/h) Total dose (mSv)< Radionuclide contaminated conditions >Control (0.96)
174
1.3 ± 0.159226
78 ± 50320837
422 ± 41400
1235
528 ± 47515
1705
680 ± 47
< Chronic gamma-irradiation >Background
0.1
82
5
3.0
145
50
29.6
150
500
296
198
5000
2960
192
50000
29600
292

Radiation-induced
0
52
663
1061
1531
0
63
68
116
110
210

Table 18 Yield of chromosome aberrations (%) by chronic irradiation in root apical meristems ofdifferent plant species (activity of substrate 70,000 Bq.l-1) (4)Plant species
Control
1986
1987
1988
1989
Lupinus alba
0.9
19.4
20.9
14.0
15.9
Pisum sativum
0.2
12.9
14.1
9.1
7.9
Secale cereale
0.7
14.9
18.7
17.1
17.4
Triticum aestivum
0.9
16.7
19.3
17.7
14.2
Hordeum vulgare
0.8
9.9
11.7
14.5
9.8
Table 19 Yield of albina chlorophyll mutation (%) in rye in the 30 km Zone (4, 11)Contaminated soil (137Cs, 137Cs, 144Ce, 106Ru and others,
Variety of rye
Control
180,000 Bq.kg-1)
1986
1987
1988
1989
Kiev-80
0.01
0.14
0.40
0.91
0.71
Kharkow-03
0.02
0.80
0.99
1.20
1.14
26

1. There are no plausible differences related tonon-specific diseases between the people living on
the contaminated territories and the control groups;
2. Techniques for diagnosis verification has become
last years much better than ten years ago. Hence acomparison between epidemiological data obtained
before and after the Accident is improper operation;
3. Deterioration of the state of health can be considered
as a result of other affecting factors; a lowering oflife
conditions,
includingnutrition,andpsychological stresses impact. As this takes place,so-called “radiophobia” attracts the largest notice.
I am sure that there are at least two means ofapproach to interpreting the epidemiological data inorder to solve these contradictions.
In context of this assumption I would like to outline
two considerations.
- The first consideration. Irradiated groups of people
on contaminated territories are too numerous andthey could not advantageously be compared withanother groups. So it is difficult to find adequategroups for comparison. Actually let us see a map of
total mortality of people in Ukraine. The
contaminated territories are found in the regions
where, before the Accident, mortality of people waswell below than in many other regions of Ukraine.
Hence it makes sense to consider the whole
population of Ukraine as the control group forcomparison of indexes of morbidity and mortality.
The alternative is to use a comparative analysis of
the tendencies for morbidity alteration.
- The second consideration. The data ofradiobiological investigations should be used inanalyzing real causes of health deterioration inpeople. Choosing correct controls in radiobiologicalexperiments is fully possible and we know many
biological test-systems particularly well suitable for
evaluating the dose-dependence of the main cellularand molecular genetic processes which can be
primary events of radiological effects.

to consider the morbidity augmentation as a result
having been associated with the factors of
non-radioactive origin (chemical compounds, heavy
metals and mainly social-psychological syndrome
development).
The Chernobyl catastrophe has implied a heavy
burden for Ukraine: pollution of air, water, soils andvegetation in all ecosystems, late radiological effects
in the health of people, losses of arable land and forest,
necessity of mass-evacuation from thousands ofsettlements in the contaminated regions, severe
psychological shock for millions of people, and painful
suffering of unexpected life tragedies.
Eleven years after, this tragic event with its causes
and consequences brings one to very important
conclusions concerning moral aspects of humanrelations within the nuclear society, as well asinteractions between the society and the environment.

References
1. Chernobyl Catastrophe/ Kiev: Naukova dumka.
1995. -547p. (in Russian).
2. Chernobyl catastrophe: causes and consequences.
Part 1 / Minsk: Senmurv. 1993. -242p. (In Russian).
3. Chernobyl catastrophe: causes and consequences.
Part.4 /Minsk:Senmurv. 1993.- 242p.(In Russian).
4. Grodzinsky D.M., Kolomietz O.D., Kutlachmedov
Yu. Antropogenic radionuclide Anomaly and Plants. /Kiev: Naukova dumka. 1991. -158p. (In Russian).
5. Data of the National Commission on RadiologicalProtection of Ukraine, 1996.
6. Medical Ukraine/ 1996, No 3, p.9-10. (In Ukrainian).
7. Data of the Ministry of Health of Ukraine.
8. Indexes of Health of victims due to the accident at
the Chernobyl Power Plant (1987 - 1995). Kiev:
Center of Medical Statistics. 1996. p.4-6. (InUkrainian).
9. Data of the Institute of Endocrinology of the
Academy of Medical Sciences of Ukraine, 1997.
10. Bubryak I., Naumenko V., Grodzinsky D. Genetic
damages occurred in birch pollen in condition ofradionuclides contamination/ Radiobiologia, 1991,
vol.31, No 4. p.563-567 (In Russian).
11. Grodzinsky D.M. Late effects of chronic irradiationin plants after the accident at the Chernobyl Nuclear
Power Station / Radiation Protection Dosimetry.
1995, vol.62, No 1/2. p.41-43.
12. Boubryak I., Vilensky E., Naumenko V.,
Grodzinsky D. Influence of combined alpha, beta andgamma radionuclide contamination on the frequencyof waxy-reversions in barley pollen / Sci. total
Environ. 1992, 112. p.29-36.

Conclusion
Following the Chernobyl Nuclear Accident on
April 26,1986, epidemiological analyses of data point
to impressive deterioration of the health of the people
affected by radionuclide contamination in theenvironment. This deterioration of population healthembraces a broad spectrum of diseases.
Epidemiological prediction of the rate of thyroid
cancer in children near Chernobyl seems strikingly
compatible with a real increase. But there is a tendency

27