ResearchPDF Available

Abstract and Figures

Summary Title: “Chernobyl: 30 Years of Radioactive Contamination Legacy” Lead writer and coordination of report: Prof. Valerii Kashparov The consequences of the Chernobyl accident – the largest radiation accident in the world - including data accumulated during the last 30 years are observed in this report. It is noted that until now there has been no reliable information on the dynamics of the radionuclides release during the accident and the long-term behaviour of the radionuclides in the environment, which have fallen out in the content of the particles of the exposed nuclear fuel. The fuel particles are a specific form of Chernobyl radioactive fallout. The results of the use of protective measures after the accident and changes to Protective Action Levels caused by these measures were analyzed. The possibility of changes in the zone division of the radioactively contaminated territories was considered. The possibility of re-evacuation of the population and use of the Chernobyl Exclusion Zone in economic activity were also considered. Analysis of the current radiological situation outside the Exclusion Zone was conducted, and methods leading to the improvement of this situation are proposed. Keywords: Cesium, Strontium; Plutonium; Americium; Chernobyl, Chernobyl accident; Chernobyl NPP; Terrestrial density of contamination; Chernobyl Exclusion Zone; Radioactive fallout; Fuel particles; Countermeasures; Ionizing radiation, Rehabilitation, Remediation http://www.uiar.org.ua/30_years.htm
Content may be subject to copyright.
Ukrainian Institute of Agricultural Radiology (UIAR) of
National University of Life and Environmental Sciences of Ukraine
(NUBiP of Ukraine)
Mashinobudivnykiv Str. 7, Chabany, Kyiv-Svjatoshin distr., Kyiv reg., 08162 UKRAINE
phone: (38044) 526 1246, fax: (38044) 526 0790, e-mail: vak@uiar.kiev.ua, www.uiar.org.ua
.
Report
Chernobyl: 30 Years of Radioactive Contamination Legacy
Lead writer and coordination of report
Professor Valerii Kashparov
Kyiv - 2016
1
Analysis by
Prof. Valerii Kashparov
Director of UIAR of NUBiP of Ukraine
Dr Sviatoslav Levchuk
Head of the Laboratory of UIAR of NUBiP of Ukraine
Prof. Iuryi Khomutynyn
Head of the Laboratory of UIAR of NUBiP of Ukraine
Dr Valeriia Morozova
Researcher of UIAR of NUBiP of Ukraine
Marina Zhurba
Researcher of UIAR of NUBiP of Ukraine
Commissioned by Greenpeace Belgium
This report, publications discussed, and conclusions made are solely the responsibility of the
authors
Acknowledgements
We gratefully acknowledge James Peter McAllister, Elena Anastopoulos and Iryna Labunska, UK,
for their valuable help in editing the English translation of the document!
2
Table of Contents
Summary .............................................................................................................................................. 4
List of conventional signs and abbreviations ....................................................................................... 5
1. Introduction: The Chernobyl Accident ............................................................................................ 6
1.1. Timing and scale of radioactive releases ................................................................................... 6
1.2. Background on Radioactive Contamination and Evacuation .................................................. 13
1.3. Overview of Protective Action Levels after the nuclear disasters ........................................... 21
1.4. Proposed changes to Protective Action Levels and analysis of those changes ....................... 24
1.5. Radiation protection of environment ....................................................................................... 26
1.6. Proposed changes to Protective Action Levels ........................................................................ 27
2. Chernobyl’s Contamination 30 years later with sections on food, environment (ground and
wildlife) and water ............................................................................................................................. 28
2.1. Evacuation Zones Around Chernobyl and general evacuation policies .................................. 29
2.1.1. Special Zone of Radiation Danger (SZRD) of the ChNPP ............................................... 33
2.1.2. Biosphere Radiological Reserve in ChEZ ........................................................................ 35
2.2. Proposals to lift evacuation zones around Chernobyl ............................................................. 37
2.3. Risks of recontamination — forest fire .................................................................................. 39
2.4. Radiological situation outside the ChEZ ................................................................................ 44
2.4.1. 137Cs .................................................................................................................................. 44
2.4.1.1. Milk ................................................................................................................................ 45
2.4.1.2. Wild mushrooms and berries ......................................................................................... 46
2.4.2. 90Sr .................................................................................................................................... 47
2.4.2.1. Cereal ............................................................................................................................. 47
2.4.2.2. Firewood ........................................................................................................................ 48
3. Analysis of interplay of current levels of radioactive contamination and Evacuation Policies in
Ukraine, Belarus, Russia .................................................................................................................... 49
Conclusion .......................................................................................................................................... 53
References .......................................................................................................................................... 54
3
Summary
Title: “Chernobyl: 30 Years of Radioactive Contamination Legacy
Lead writer and coordination of report: Prof. Valerii Kashparov
The consequences of the Chernobyl accident the largest radiation accident in the world -
including data accumulated during the last 30 years are observed in this report. It is noted that until
now there has been no reliable information on the dynamics of the radionuclides release during the
accident and the long-term behaviour of the radionuclides in the environment, which have fallen out
in the content of the particles of the exposed nuclear fuel. The fuel particles are a specific form of
Chernobyl radioactive fallout.
The results of the use of protective measures after the accident and changes to Protective
Action Levels caused by these measures were analyzed.
The possibility of changes in the zone division of the radioactively contaminated territories
was considered. The possibility of re-evacuation of the population and use of the Chernobyl
Exclusion Zone in economic activity were also considered.
Analysis of the current radiological situation outside the Exclusion Zone was conducted, and
methods leading to the improvement of this situation are proposed.
Keywords: Cesium, Strontium; Plutonium; Americium; Chernobyl, Chernobyl accident; Chernobyl
NPP; Terrestrial density of contamination; Chernobyl Exclusion Zone; Radioactive fallout; Fuel
particles; Countermeasures; Ionizing radiation, Rehabilitation, Remediation
4
List of conventional signs and abbreviations
AED
Annual effective dose
Bq; kBq
Activity unit — Becquerel, c-1; 1 kilo Becquerel=1000 Bq
Bql-1; Bqkg-1
Volume or mass specific activity
BSS
Basic Safety Standards
BY
Belarus
ChBRR
Chernobyl Biosphere Radiological Reserve
ChEZ
Chernobyl Exclusion Zone
ChNPP
Chernobyl Nuclear Power Plant
Ci
Activity unit Curie, 1 Ci=3.71010 Bq
Cikm-2
Terrestrial contamination density unit, 1 Cikm-2=37 kBqm-2
EDR
Equivalent and effective dose rate, units mSvh-1; μSvh-1 mSvy-1
EU
European Union
FP
Fuel particles
EPIC
Environmental Protection from Ionizing Contaminants
Gy
Absorbed dose unit — Grey
IAEA
International Atomic Energy Agency
ICRP
International Commission on Radiological Protection
INES
International Nuclear Event Scale
kBqm-2
Terrestrial contamination density unit
Kg
Unit of mass — kilogram
L
Unit volume — liter
mGy·d-1
Absorbed dose rate unit, milliGrey per day,
mRh-1
Exposure dose rate unit, milliRoentgen per hour, 1 mRh-1 is about
10 μSv
h
-1
NPP
Nuclear Power Plant
NUBiP of
Ukraine
National University of Life and Environmental Sciences of Ukraine
PL
Permissible levels
PNEDR
Predicted no effect dose rate
RNG
Radioactive noble gases
RSSU-97
Radiation Safety Standards of Ukraine
RU
Russia
SZRD
Special Zone of Radiation Danger
Sv; mSv; μSv
Equivalent and effective dose unit — Sievert; 1 milliSievert=0.001 Sv;
1 microSievert=0.000 001 Sv
SZRD
Special Zone of Radiation Danger
T1/2
Half-life of the radionuclide
TPL
Temporary Permissible Levels
TUE
Transuranic elements
UA
Ukraine
UIAR
Ukrainian Institute of Agricultural Radiology
UNSCEAR
United Nations Scientific Committee on the Effects of Atomic Radiation
USSR
Soviet Union
5
1. Introduction: The Chernobyl Accident
The Chernobyl accident which took place on April 26, 1986 is the largest radiation
catastrophe in history (INES Level 7: Major accident). As a result of the Chernobyl accident, a
considerable territory of Belarus, Russia and Ukraine, as well as of Western Europe, primarily the
Scandinavian countries and Alpine region, was the most severely contaminated. Until now there has
been no consensus on the dynamics and values of the radionuclides release (especially for volatile
radionuclides) during the Chernobyl accident.
The first official announcement of the accident at Chernobyl Nuclear Power Plant (ChNPP)
was made on television on April 28, 1986. In a rather scholastic report the fact of the accident was
communicated, including the deaths of two people. Later, the actual scale of the accident started to
be communicated. Concerns for prevention of panic amongst the population were given as an
argument for the accident’s secure classification. However, the fast and well-organized evacuations
of the residents of Pripyat and Chernobyl (April 27, 1986 and May 06, 1986 respectively) promptly
became known to the population of Ukraine, Belarus and Russia. At the same time, by the middle of
May 1986, doctors of the Ministry of Health, scientists and mass media were forbidden to inform
citizens of the USSR about the activities carried out to minimize the impact and consequences of
the accident, protection methods, and scale of the accident. It resulted in a large part of the
population, particularly those living in rural areas, using garden and farm products, particularly
milk. This led to increased exposure, with particular effect on the thyroid gland. Maps of radiation
contamination and radiation levels were classified until 1990. (Ministry of Ukraine of Emergencies,
2011). For the purposes of strategic planning of radiation exposure protection of the population a
temporary annual effective dose limit of 100 mSv for the period from April 26, 1986 to April 25,
1987 was set by the USSR Ministry of Health. The population resettlement after the Chernobyl
accident was carried out at the levels of terrestrial contamination by radionuclides and the radiation
doses of population that were lower than that ones used according to the current Radiation Safety
Standards of Ukraine.
In the later phase of the Chernobyl accident in the settlements the effective dose of external
and internal exposure for a representative person is respectively 1.8 times and 3 times higher than
the average dose for population in the settlement (IAEA, 2006). Therefore, the limit adopted in
Ukraine of an average annual effective dose for population radiation exposure of 1 mSvy-1
corresponds to an annual effective dose to the representative person of 2–3 mSv. Using the
reference level of an annual effective dose to the representative person of 1 mSvy-1 the average
annual effective dose for the population in a settlement will be of 0.3–0.5 mSv. Therefore, the use
of reference level of an annual effective dose to a representative person of 1 mSv will result in a
significant increase of the zone size according to the Law of Ukraine.
There were no standards of environmental radiation protection when the Chernobyl accident
occurred.
1.1. Timing and scale of radioactive releases
Durable (for 10 days) dynamics of radioactive substances released from the Chernobyl
reactor during the accident (Fig.1.1), as well as the change of meteorological conditions (Fig. 1.2)
(Chernobyl, 1996) provided a complex picture of contamination of the vast territories (Fig. 1.3).
6
a
b
Fig. 1.1: Dynamics of 131I (a) and 137Cs (b) release from Chernobyl reactor in April 26 - May 5,
1986: 1- Abahyan, et al.1986 and 2 – Izrael, et al., 1987
Fig. 1.2: The trajectories of radioactive contamination of the territory (Chernobyl, 1996).
0
5
10
15
20
25
Apr 26 Apr 27 Apr 28 Apr 29 Apr 30 1 May 2 May 3 May 4 May 5 May
PBq
Date
1
2
0
5
10
15
20
25
Apr 26 Apr 27 Apr 28 Apr 29 Apr 30 May 1 May 2 May 3 May 4 May 5
PBq
Date
1
2
7
a
b
Fig. 1.3: Density of 137Cs contamination of Europe (a) (De Cort, et al., 1998) and SIC (b) (IAEA,
1991)
8
As a result of the initial explosion on April 26, 1986 a very narrow (100 km long and up to
1 km wide) straight western fuel trace of radioactive fallout was formed (in the direction of Tolsty
Les village). The trace of the contamination is characterized mainly by finely dispersed nuclear fuel
(Fig. 1.4). This trace of fallout could have been formed only by short-term release of fuel particles
(FP) with overheated vapour to a low height at night time with stable atmosphere. It is considered
that at the moment of the accident surface winds were weak with no particular direction, and only at
a height of 1500 m there was south-western wind with a velocity of 8–10 ms-1 (IAEA, 1992).
Cooling of the release cloud resulted in the decrease of its volume, water condensation and wet
deposition of radionuclides (moist radioactive fallout). The western fuel trace contains only about
10–15 % of the fuel particles that have been released outside the Chernobyl Nuclear Power Plant
(ChNPP) industrial site during the accident. Later, the main mechanism of the fuel particles’ (FP)
formation was the oxidation of the nuclear fuel (Kashparov, et al., 1996). The absence of
experimental data on meteorological conditions in the area of the ChNPP (the closest observations
were carried out only at a distance of more than 100 km (Izrael, et al., 1990; Talerko, 1990), as well
as the absence of the information about source of the radionuclide release including data on the
dispersion composition of radioactive fallout, did not allow an efficient prediction of the nearest
zone contamination to be made.
Up to this point, the nature and timing of the formation of the cesium southwest trace of
radioactive fallout in the area of the settlements "Vesnyanoe - Poliske - Bober" are still unclear
(Fig. 1.3, 1.4). Probably, this trace was formed on the first day of the accident on April 26, 1986
after the destruction of the reactor and fuel heating due to the remaining heat generation that caused
the increase of the volatile fission products leakage such as radioactive noble gases (RNG) and the
iodine and cesium radioisotopes. Until now there has been no consensus on the dynamics progress,
(Fig. 1.1) nor the values of the radionuclides release (especially for volatile radionuclides) during
the Chernobyl accident (Table 1.1). The increase of the iodine and cesium radionuclides release
during the first days after the accident seems more reliable than the decrease of it. But the decrease
of radionuclides release after the reactor destruction is generally accepted (Fig. 1.1) (Izrael, et al.,
1990). Usually describing the radionuclides release during the Chernobyl accident instead of
radionuclides activity the activity of the so-called radioactive materials is used (these materials are
often associated with nuclear fuel) (IAEA, 2006; Ministry of Ukraine of Emergencies, 2011).
For the integral value of the release, most reliable data were obtained only for long-lived
cesium radioisotopes and for radionuclides contained in the fuel component of the radioactive
fallout. These values were obtained years after the accident on the basis of mapping of
radionuclides contamination over vast territories.
The relative release of fission products of uranium (IV) oxide at high temperatures decreases
with the increase of them binding energy with oxygen in the following sequence: Kr> Xe> I> Ag>
Cs> Te> Sr> Ru> Ba> Zr> Ce (Andriesse & Tanke, 1984). Information about the dynamics of the
iodine radioisotopes release is the most controversial, because during the high-temperature
annealing of the irradiated nuclear fuel the relative release of the iodine radioisotopes is much
higher than the relative release of the radioactive cesium. Thus the relative release of the iodine
radioisotopes and the relative release of the radioactive cesium cannot be equal, as it is shown in
Fig. 1.1. At the same time the ratio of 131I/137Cs activity in the radioactive fallout was changing
during the first days of the accident. For this reason the reconstruction of the terrestrial
contamination density of 131I according to the later obtained maps of the terrestrial contamination of
137Cs was not fully correct. The main part of the radioiodine release should have occurred during
the first 3 days of the accident (on April 26–28, 1986) in the western, northern and eastern
directions, but not in the southern route, when there was no more iodine in the fuel (Fig. 1.2) (The
Atlas, 2009). The reconstruction of the terrestrial contamination of iodine radioisotopes depending
on the release dynamics and the direction of their transfer with the air flow was extremely important
for the reconstruction of the radiation doses for the population in the acute period of the accident.
9
a
b
Fig. 1.4: Density of 137Cs (a) and 239240Pu (b) contamination of ChEZ (Kashparov, et al., 2001;
Kashparov, et al., 2003)
10
As a result of the clustered fuel heatup during April 2630, 1986, highly mobile volatile
fission products (radioactive noble gases, iodine, tellurium, and cesium) were released from nuclear
fuel and raised in the convective flow to a height above 1 km on April 26, 1986, and to 600 m in the
following days (IAEA, 1992; Izrael, et al., 1990). The highest release of the radioactive cesium
occurred at maximum heating of the fuel on April 27–28, 1986. (Fig. 1.1). This caused the
formation of the south-western (the settlements "Poliske - Bober"), north-western (spreading to
Sweden), western and north-eastern condensed radioactive traces with insignificant decreasing
portion of oxidised fuel particles, that had been formed at a temperature below 1200 K on the
periphery of the heating areas. Cesium spots outside the ChEZ were formed at the rate of 137Cs
fallout with precipitation. When the temperature in the reactor decreased (April 30–May 03, 1986),
and thus, the release of volatile fission products from the fuel became less (Izrael, et al., 1990), the
dispersion of nuclear fuel at the rate of its oxidation in the air became more important (this process
is the most intensive at the temperature 600–1200K). This provided the formation of the southern
fuel trace of radioactive fallout in the direction of Kiev and Tarashcha. After the covering of the
reactor, heat exchange of fuel deteriorated. Bad heat exchange of fuel caused the rise in temperature
(May 03–06, 1986), increase of the release of volatile fission products and melting of materials,
which covered the fuel. Aluminosilicates form thermally stable compounds with many fission
products and bind cesium and strontium very well at high temperatures (Hilpert & Nurberg, 1983).
It caused a sharp reduction of the release from the destroyed reactor due to the formation of fuel-
containing lava on May 06, 1986.
The changes of the nuclear fuel annealing temperature during the accident had a strong
effect on both the release ratio of different volatile fission products (migratory properties of Xe, Kr,
I, Te, Cs increase with the temperature rise and may differ significantly in the presence of UO2), as
well as on the destruction rate of the nuclear fuel during its oxidation with the formation of
micronic fuel particles (Kashparov, et al., 1996). Mainly the area near the accident was
contaminated by the radionuclides (90Sr, 238241Pu, 241Am, etc.) of the fuel component of the
Chernobyl radioactive fallout. This area was the Exclusion Zone and the adjacent territories in the
north of the Kiev region and west of the Chernihiv region, and also Bragin and Hoyniki districts of
Gomel region (Belarus). The contamination of the near area only occurred due to the following
reason. In the atmosphere the rate of the dry gravitational sedimentation of the fuel particles is
higher, because of their high density (about 10 gcm-3), than the sedimentation of lightweight
condensation particles containing iodine and cesium radioisotopes.
Low activity and sensitivity of the available equipment did not allow to detect 110mAg, in
most cases, in the soil after the Chernobyl accident. However, it has been detected in the liver of
cattle at levels frequently exceeding 134,137Cs content in it (Kashparov, 1987).
One of the characteristics of the accident at ChNPP is the presence in the fallout of fuel hot
particles with the matrix of uranium oxides with various admixtures. Radionuclide composition of
fuel particles is similar to the composition of irradiated nuclear fuel from Unit 4 during the accident
(Table 1.1), but it is characterised by the fractionation of volatile highly mobile fission products
(Kuriny, et al., 1993). Fuel particles were found in the radioactive fallout both in close proximity to
the reactor (Kuriny et al., 1993; Krivokhatsky, et al., 1991; Salbu, et al., 1994) and at a considerable
distance from it in European countries: Finland, Sweden, Norway, Lithuania, Poland, Germany,
Czech Republic, Austria, Switzerland, Hungary, Romania, Bulgaria, Greece, etc. (Jost, et al., 1986;
Kauppinen, et al., 1986; Kolb, 1986; Mattsson & Hatakka, 1986).
According to various estimates (IAEA, 1996a; Kashparov, et al., 2003; The Atlas, 2009;
UNSCEAR, 2008) 100% of noble radioactive gases, 20–60% of iodine isotopes, 12–40% of
134,137Cs and 1.4–4% of less volatile radionuclides (95Zr, 99Mo, 89,90Sr, 103,106 Ru, 141,144Ce, 154,155Eu,
238241Pu etc.) in the reactor at the moment of the accident were released to the atmosphere during
the accident (Table 1.1).
Dynamics of the release, and dispersion composition of aerosol and meteorological
parameters (including precipitation) determined the formation of radioactive contamination of the
territory during the accident at ChNPP.
11
Table 1.1: Radionuclides activities in the ChNPP Unit 4 (on May 06, 1986) and their relative
release outside the ChNPP industrial site during the accident (the value printed after ± indicates an
error of estimation data from Kashparov, et al., 2003; UNSCEAR, 2008).
Radionuclide
Radionuclide activity in
the ChNPP Unit 4 (Bq)
Radionuclide relative release, %
previous estimate*
present estimate
3H
1.41015
-
-
85Kr
3.01016
100
100
90Sr
2.31017
4.0±2.0
1.8±0.6
95Zr
5.81018
3.2±1.6
1.4±0.5
106Ru
8.61017
2.9±1.5
1.4±0.5
125Sb
1.51016
-
1.4±0.5
129I
8.01010
20±10
5060
131I
3.11018
20±10
5060
133Xe
7.01018
100
100
134Cs
1.71017
10±5
33±10
137Cs
2.61017
13±7
33±10
144Ce
3.91018
2.8±1.4
1.4±0.5
154Eu
8.51015
3.0±1.5
1.4±0.5
238Pu
1.31015
3.0±1.5
1.4±0.5
239Pu
9.21014
3.0±1.5
1.4±0.5
240Pu
1.51015
3.0±1.5
1.4±0.5
241Pu
1.81017
3.0±1.5
1.4±0.5
241Am
1.61014
3.0±1.5
1.4±0.5
*- Reported by USSR State Committee on the Utilization of Atomic Energy (1986)
As the result of the Chernobyl accident the south-western part of the East-European plain
and the Ukrainian and Belorussian Polessye were the most contaminated areas (Fig. 1.3).
During the first month after the Chernobyl accident the short-lived 131I with a half-life T1/2=8
days (Table 1.2) was the most dangerous (caused the highest health risk for the population). The
surface contamination of vegetation by 131I (effective ecological half-life is about 5 days) was the
cause of milk contamination and rural population intake of iodine radioisotopes, which has led to
high radiation doses and later to thyroid cancer (Ministry of Ukraine of Emergencies, 2011).
35 Days after the accident, the 131I activity had decreased to the value of the 137Cs activity, and by
the end of 1987 there was not one atom of 131I released during the accident in the environment. One
month after the accident, the biggest radiological danger was posed by the cesium radioisotopes
(134,137Cs) throughout the radioactively contaminated area and strontium-90 (90Sr) in the 30-km
Chernobyl Exclusion Zone (ChEZ). Now, 30 years after the accident, the activity of 137Cs and 90Sr
has decreased by a factor of 2 because of radioactive decay (T1/2=30 years and 29 years,
respectively). The radioactive contamination of the ChEZ by the long-lived radionuclides 239Pu
(T1/2= 24100 years) and 240Pu (T1/2=6563 years) will persist for millennia.
The ratio of 131I/137Cs activity in the radioactive fallout, that was calculated for a single
timepoint in order to register the radioactive decay, was changing during the first days of the
Chernobyl accident. For this reason the reconstruction of the terrestrial contamination density of 131I
according to the later obtained maps of the terrestrial contamination of 137Cs was not fully correct.
The reconstruction of the terrestrial contamination of iodine radioisotopes depending on the release
dynamics and the direction of its transfer with the air flow was extremely important for the
reconstruction of the radiation dose for the population in the acute period of the accident.
It is believed that the release of iodine radioisotopes during the Chernobyl accident was
much higher than the release during the accident at the Fukushima-1 NPP (Table 1.2). However its
absolute value depends on the date according to which the 131I activity was calculated. It is also very
difficult to evaluate the injection of iodine and cesium radioisotopes into the ocean. According to
12
calculations (Stohl, A., et al., 2012) the release of noble gases (85Kr and 133Xe) during the accident
at the Fukushima NPP (Table 1.2) was higher than for the Chernobyl accident (Steinhauser et al.,
2014). This indicates that the addition and correct estimation of the release of iodine and cesium
radionuclides during the Fukushima Dai-ichi nuclear power plant accident is necessary.
Before the Chernobyl accident, information about the radionuclides behaviour in the
environment and the extent of the radiological risk of contamination by the radionuclides of fuel hot
particles was absent. It resulted in erroneous forecasts during estimation of the changes in the
radiological situation, such as overestimating the content of strontium radioisotopes in water and
food products, and alpha-emitting radionuclide content in the air.
Table 1.2: Comparison of the atmospheric release estimates of radiological important
radionuclides for the nuclear accidents at Chernobyl and Fukushima NPPs (Kashparov, et al., 2003;
UNSCEAR, 2008; Steinhauser, et al., 2014; Aliyu, et al., 2015).
Radionuclide
T
1/2
Release, PBq
Chernobyl
Fukushima
85Kr
10.75 y
33
44
133Xe
5.25 d
6500
14000
131I*
8.03 d
1760**
150
134Cs
2.07 y
47
12
137Cs
30.1 y
85
12 (6.1–62.5)
90Sr
28.9 y
4
0.02
239+240Pu
24100 y and 6560 y
0.03
(1-2)10-6
Total (excluding
noble gases)
~5300
~520
*- the lower threshold of an INES 7 accident is tens PBq
** - two levels of magnitude larger than the lower threshold of an INES 7 accident
1.2. Background on Radioactive Contamination and Evacuation
The accident at the ChNPP is the largest radiation catastrophe in the history of humanity and
resulted in the industrial radioactive contamination of all European countries (Fig. 1. 5). Primarily,
the Chernobyl accident had a negative impact on the rural population and agricultural production of
the three most affected countries: Belarus, Russia and Ukraine (Fig. 1.3). More than 150,000 km2 of
these three countries has been designated to various zones of radioactive contamination (Table 1.3).
In general, 70% of released cesium and almost all 90Sr and transuranic elements (TUE) in the fuel
particle forms were deposited in these three countries. About one third of the contaminated territory
was agricultural land. This extensive contamination of agricultural and semi-natural land had a
significant effect on humans via contaminated food consumption. Over time, the impact of forest
ecosystems (accounted for about a third of the contaminated area) on the radionuclides human
intake has increased.
13
Fig. 1.5: Terrestrial contamination density of 137Cs in Europe exceeding 40 kBqm-2, thousands km2
(De Cort, et al., 1998).
Population was resettled from the most contaminated areas (6200 km2 in Belarus (Ministry
for Emergency Situations of the Republic of Belarus, 1994), 193 km2 in Russia, 4200 km2 in
Ukraine, including 2000 km2 outside the Chernobyl Exclusion Zone (Radiological state, 2008).
Also, traditional economic activity was stopped or largely limited in these territories.
Table 1.3: The area of the territories in Belarus, Russia and Ukraine contaminated with 137Cs after
the Chernobyl accident on 10.05.1986 (estimated in 1998) (Ministry of Ukraine of Emergencies,
2011; De Cort, et al., 1998; The Atlas, 2009), thous. km2
Country
Total area,
thous. km2
Contamination density, kBqm-2
Total
40–
100
100–
185
185–
555
555–
1480
>1480
Russia (European part)
3800
44
7.2
5.9
2.2
0.46
59.8a
31.1b
Belarus
210
21
8.7
9.4
4.4
2.6
46.1
Ukraine
600
29
4.3
3.6
0.73
0.56
38.2c
21.5d
The regime of secrecy of the true extent and consequences of the accident, the disadvantages
of the management system and the limits of material resources made it impossible to use stable
iodine drugs (iodine prophylaxis) operatively for the radiation protection of personnel and the
general population during and after the Chernobyl accident. The evacuation of the population
around the ChNPP was carried out quite quickly and in an orderly way.
In the period from April 26 to May 6, 1986 when the main part of the release occurred and
radioactive contamination of the territory was arisen, the evacuation of population was being carried
out for the prevention of acute radiation injuries among the population and to avoid exceeding the
a 65.1 thous. km2 according to the estimation provided in 2006
b on 2006
c 42.8 thous. km2 according to the National report in 2011
d on 2011 14
set "Criteria of Decisions to Be Taken on Measures for People Protection in Case of a Reactor
Accident" (Ill`in & Avetisov, 1983):
External gamma exposure
0.75 Sv
Thyroid exposure in the result of radioactive iodine intake
2.5 Sv
Integrated concentration of iodine-131 in the air, MBq.s.l-1:
for children
14.8
for adults
25.9
Total intake of iodine-131 with food, MBq.day-1
0.555
Maximum contamination by iodine-131 of fresh milk, MBq
.
l
-1
, or a day
ration, MBq
.
day
-1
0.037
The initial density of the iodine-131 fallout on the pasture, MBq.m-2
0.259
The initial evacuation zone was formed as a result of arbitrary decisions made on the basis
of geographical indication, forming a circle around the Chernobyl nuclear power plant with a radius
of 30 km. In the initial phase of the accident (until May 7, 1986) 99,195 people were evacuated
from 113 settlements including 11,358 people from 51 villages in Belarus and 87,837 people from
62 settlements in Ukraine (including about 45,000 people evacuated at 14.00–17.00 on April 27,
1986 from the town of Pripyat located 4 km from the ChNPP).
In the acute period after the accident, it was not possible to differentiate the levels of
contamination in animals (live monitoring and clean feeding of animals) and in the period of May-
July 1986, the total number of slaughtered animals reached 95,500 cattle and 23,000 pigs evacuated
from ChEZ. A technique for in vivo measurements of 137Cs in animals (live monitoring of animals)
that effectively reduced the production of contaminated meat was developed and used since 1987.
Before the introduction of this method, in light of a lack of clean forage for the evacuated animals,
difficulties in managing large numbers of animals, they could die that would cause a panic among
the population. And in order to prevent the psychological influence of possible death of animals on
the population, more than 100,000 agricultural animals were slaughtered. The 134,137Cs content in
the meat of these animals exceeded the permissible levels (3700 Bqkg-1). Taking into account the
deficiency of meat products in the USSR, it was decided to mix this meat with clean meat for the
production of meat products that satisfied hygiene standards, decision which angered society. As a
result, meat from the ChEZ was not used and was stored in refrigerators in various regions of the
USSR for several years, and eventually it was buried in the Exclusion Zone.
The analysis of live data on the radiation situation conducted in May 1986 revealed that the
territory of the radioactive contamination where comprehensive measures for population protection
were required extended far beyond the ChEZ 30-km zone. For the purposes of strategic planning of
radiation exposure protection of the population, a temporary annual effective dose limit of 100 mSv
for the period from 26 April 1986 to 25 April 1987 (50 mSv from external and 50 mSv from
internal dose) had been set by the USSR Ministry of Health. For the practical implementation of the
concept of the emergency division of zones the derivative levels were introduced. These levels
corresponded to the basic dose criteria and the appropriate dose quotas.
For the division of zones according to external dose rate it was proposed that the average
value of the dose rate of gamma radiation in an open air area cited on May 10, 1986 be used. In this
case, on May 10, 1986 the annual external dose rate for the critical group of the population of
11 mSv corresponded to the value of the exposure dose rate of 1 mRh-1 (about the equivalent dose
rate (EDR) of gamma radiation of 10 μSvh-1 ).
The following zones were established:
> 20 mRh-1(>200 µSvh-1) Exclusion Zone, it is the territory where the population was
evacuated forever;
5–20 mRh-1 (50200 µSvh-1) the Temporary Evacuation Zone, residents were
supposed to return to this territory after the normalization of radiation situation;
3–5 mRh-1 (3050 µSvh-1) Strict Controlled Zone, it is the territory, where the
organized resettlement of children and pregnant women to clean areas for summer period in 1986
was conducted. 15
For the zone division according to the internal dose rate it was proposed at the end of May
1986 to use the average density of long-lived biologically significant radionuclides 137Cs, 90Sr,
239,240Pu present in the surface contamination of the soil in the settlement . The numerical values of
the criteria by the surface contamination density amounted to 15 Cikm-2 (555 kBqm-2) of 137Cs, 3
Cikm-2 (111 kBqm-2) of 90Sr and 0.1 Cikm-2 (3,7 kBqm-2) of 239,240Pu. Official information
support of such division of zones was carried out at the beginning of July 1986 by the USSR State
Committee for Hydrometeorology after the approval of maps of radioactive contamination (Izrael,
et al., 1990).
According to initial assessments, the values of the internal radiation doses from 134Cs и 137Cs
in the first year after the accident in areas with terrestrial contamination density of 137Cs of
1 Cikm-2 (37 kBqm-2) accounted for 6.2 mSvy-1 for permanent residents and 2.8 mSvy-1 for
residents temporarily resettled to clean territories in a period from May 5 to September 1, 1986.
Thus, internal radiation doses of about 100 mSvy-1 for permanent residents and 50 mSvy-1 for
temporary resettled persons corresponded to the density of the contamination of 15 Cikm-2 (555
kBqm-2).
The selection of the limit of 3 Cikm-2 (111 kBqm-2) of 90Sr was determined based on the
experience of the accident at the Mayak Production Association (1957), where the value of the
density of the soil contamination of 2 Cikm-2 (74 kBqm-2) was used as a limit value for the
population habitation without any restrictions.
In evaluating the dose from plutonium, the gross simplification was accepted that the
resuspension factor by the wind at 10-7 m-1 was constant over the course of a year, except in winter .
In this case at the contamination density of 0.1 Cikm-2 (3.7 kBqm-2) of 239,240Pu the equivalent dose
in the lung in 50 years after the accident would amount to 0.3 mSvy-1.
In reality the main criterion for evacuation was the exposure dose rate (Roentgen per hour -
Rh-1). The evacuated population from the territories where the exposure dose rate exceeded
5 mRh-1 (the equivalent dose rate (EDR) about 50 μSvh-1) did not return.
In Russia, in regions further from the Chernobyl Nuclear Power Plant, mass evacuation
wasn’t performed. In 1988 the individual dose limit of 350 mSv per 70 years or 5 mSvy-1 was
accepted as a criterion for safe habitation (National Committee on Radiation Protection, 1988). This
limit encompassed the dose received during the course of a life from the total external and internal
radiation. Therefore, in 1986, the population have not been evacuated from settlements in Russia
where the contamination density was over 1.5 MBqm-2, which, obviously, was a big mistake. It
caused additional impact on the increase of the social and psychological stress on the population in
the following years.
A consolidated list of evacuated settlements in the three countries is represented in
Table 1.4.
Table 1.4: Summarized data on the resettled in 1986 territories and evacuated settlements (Ministry
of Ukraine of Emergencies, 2011; The Atlas, 2009)
Evacuation/Exclusion Zone
Square, km2
Number of the
settlements
Number of people
Belarus
1542
108
24725
Russia
193
4
186
Ukraine
2157
75
91406
Total
3699
187
116317
In Ukraine the population of 62 settlements was evacuated in May 1986. In addition, the
population from 7 settlements in the Kyiv region and 7 settlements in the Zhytomyr region were
evacuated. In Russia the evacuation was performed only in 1988: 186 people were resettled from 4
settlements.
Thus, in 1986 the boundary of the population evacuation zone was designated by the level of
equivalent dose rate of 5 mRh-1 (EDR about 50 μSvh-1). At this level of the EDR, the ratio
16
between short-lived gamma-emitting radionuclides (95Zr, 95Nb, 103,106Ru, 141,144Ce), which
precipitated with fuel particles, and long-lived condensed 137Cs was different in different parts of
the Exclusion Zone. Therefore, after the disintegration of the short-lived radionuclides the
contamination density of the Exclusion Zone by the long-lived 137Cs is very different in different
parts of the territory, especially in the fuel and condensation traces (Fig. 1.4).
Two years after the accident with the improvement of the radiation situation the dose limits
of population radiation were reduced respectively to 30 mSvy-1 and 20 mSvy-1 in the 3rd and 4th
year after the accident.
In 1988 the National Commission on Radiation Protection (NCRP) of the Ministry of Health
of the USSR proposed the concept of the limit on the received life-dose of 350 mSv per 70 years as
a regulatory framework for the long-term habitation of population. As a result of this limit the
restrictions were cancelled for a number of the contaminated areas (National Committee on
Radiation Protection, 1988).
The purpose of this Concept (Verkhovna Rada of Ukraine. On the Concept, 1991) was the
formulation of principles and justification of practical measures that were aimed at reducing the
consequences of the accident for human health, the reduction of received damage through the
decrease of the permissible radiation level received during a life-span from 350 to 70 mSv, and
guarantee of the mass evacuation of people in case of exceeding of this level.
Based on the concept (Verkhovna Rada of Ukraine. On the Concept, 1991) laws about the
legal regime of the areas affected by the Chernobyl accident were accepted in the three countries.
According to these laws the division of zones by radiation level and additional resettlement of
population were provided in 1991–1994 (Table 1.5) (Levonevsky, 1991; Legislation of Russia,
1991; Verkhovna Rada of Ukraine. On the Legal, 1991; Verkhovna Rada of Ukraine. On the Status,
1991).
Table 1.5: Criteria to establish the zones of radioactive contamination in Ukraine (Verkhovna Rada
of Ukraine. On the Legal, 1991)
Zones
Criteria to establish the zones
1. Exclusion zone
Area where the population was evacuated in 1986 (includes 30 km
zone around ChNPP)
2. Zone of an Unconditional
(Obligatory) Resettlement
Where D
eff
>5 mSvy-1 or
137Cs > 555 kBqm-2 or
90Sr > 111 kBqm-2 or
Pu> 3.7 kBqm-2
3. The Zone of a Guaranteed
voluntary resettlement
Where D
eff
>1 mSvy-1 or
185 < 137Cs <555 kBqm-2 or
5.5< 90Sr < 111 kBqm-2 or
0.37 < Pu < 3.7 kBqm
-2
4. The Zone of an Enhanced
Radioecological Monitoring
Where D
eff
>0.5 mSvy-1
37<137Cs< 185 kBqm-2,
0.74 <90Sr< kBqm-2,
0.185 <Pu< 0.37 kBqm
-2
Zone of Subsequent Evacuation and Zone of Primary Evacuation in Belarus, Zone of
Evacuation in Russia and Zone of Unconditional (Mandatory) Resettlement in Ukraine were the
areas where the average annual effective dose could exceed 5 mSv and the contamination density of
cesium radioisotopes was higher than 555 kBqm-2 or of 90Sr was higher than 111 kBqm-2 or of Pu
radioisotopes was higher than 3.7 kBqm-2.
Zone with the Right to Evacuation in Belarus and Zone of Guaranteed Voluntary
Resettlement in Ukraine (Table 1.5) were the areas where the average annual effective dose was 1
5 mSv per year and the contamination density of the cesium radionuclides was 185–555 kBqm-2 or
17
of 90Sr it was 5.55–111 kBqm-2 or of Pu it was 3.7 kBqm-2. Russia Living Zone with the Right to
Resettle was the territory with contamination density of 137Cs of 185–555 kBqm-2.
Nowadays more than 9000 settlements in Belarus (2402 settlements, Table 1.6), Russia
(4413 settlements) and Ukraine (2293 settlements, the 4th Zone has been abolished in 1290
settlements on 28 December 2014, Table 1.6) have been assigned to the zones of radioactive
contamination (Table 1.5), where about 5 million people reside.
Now the main criterion of the possibility of safe residence of population in the territory
contaminated after the Chernobyl accident is the limit of the average annual effective dose of 1 mSv
(Levonevsky, 1991; Legislation of Russia, 1991; Verkhovna Rada of Ukraine. On the Legal, 1991).
Because of the acceptance of international principles and recommendations, the limit of the
annual average effective dose (permissible dose) of 1 mSv was adopted in 1991 in the USSR. After
the collapse of the USSR this concept was adopted in the three republics. In addition, new Radiation
Safety Standards in 2000 in Belarus (RSS-2000, 2000), in 1996, 1999 and 2009 in Russia (RSS-
99/2009, 2009) and in 1997 in Ukraine were enacted (RSSU-97, 1998).
Table 1.6: Distribution of the settlements/number of residents among radioactively contaminated
zones in the Republic of Belarus as of Jan 01, 2014; in the Russian Federation as for April 7, 2005;
in the Ukraine Jan 01, 2008
Zone name
Number of the settlements/
Number of
people, thous. people
Belarus
(BY)
Russia
(RU)
Ukraine
(UA)
Exclusion Zone (BY, RU, UA) and
Zone of Primary Evacuation (BY)
126/0
4/0
76/0.12
Zone of Subsequent Evacuation (BY),
Zone of the Resettlement (RU),
Zone of an Unconditional (Obligatory) Resettlement
(UA)
17/1.8
202/75.7
86/9.0
Zone with the Right to Evacuation (BY)
Zone of Residence with the Right to Evacuation
(RU), Zone of a Guaranteed Voluntary Resettlement
(UA)
464/112.6
492/169.2
841/637.2
Zone of Residence with Periodic Radiation Control
(BY), Zone of Residence with Privileged
Socioeconomic status (RU), Zone of an Enhanced
Radioecological Monitoring (UA)
e
1849/1028.2
3715/1372.9
1290/1645.5
Total
2402/1142.6
4413/1617.5
2293/2291.9
In the early phase, 131I was the main contributor to the internal dose through the pasture–
cowmilk pathway. Peak concentrations occurred rapidly (within about 1 day) after deposition (in
late April or early May 1986, depending on when deposition happened in certain places). In late
April/early May 1986 in Ukraine dairy cows were already grazing outdoors and there were
significant levels of the activity concentration of 131I in cow milk exceeding acceptable levels,
which ranged from a few hundred to a few tens of thousands Becquerel per litre. The activity
concentration of 131I in milk decreased with an effective half-life of 45 days owing to its short
physical half-life and the processes that removed it from pasture grass. Consumption of leafy
vegetables onto which radionuclides had been deposited also contributed to the intake of
radionuclides by humans.
e This zone was eliminated in Ukraine December 28, 2014 (On Amendments, 2015) 18
In order to decrease the internal radiation doses of the population, the first Temporary
Permissible Levels (TPL) (4104–88) were approved by the USSR Ministry of Health only on
May 6, 1986. These levels concerned the 131I activity concentrations in some foodstuffs, which were
decreasing with the improving radiological situation (Table 1.7). The next TPLs adopted on 30 May
1986 (TPL 129–252) concerned the content of all beta-emitters in food products caused by surface
contamination but were primary focused on the ecologically mobile and long-lived cesium
radionuclides. The latter TPLs put in force since 1988 (TPL-88) and 1991 (TPL-91) referred to the
sum of 134Cs and 137Cs activities. TPL-91, for the first time included TPLs for both cesium
radionuclides and 90Sr.
Before the Chernobyl accident there were not any permissible levels (PL) for radionuclides
in foodstuff in the USSR. Permissible levels for 131I in milk (370 Bql-1) that were ten times lower
than the previous ones were already accepted in Austria on May 02, 1986. And it was recommended
to use milk below 185 Bql-1 for drinking purposes. The permissible level of 137Cs in baby food of
11 Bqkg-1 was accepted in Austria on May 23, 1986 (IAEA, 1994.).
In the USSR including time of the Chernobly accident, the food production system could be
divided into two groups: large collective farms and small private farms. Collective farms routinely
used land rotation combined with ploughing and fertilisation to improve productivity. Traditionally
small private farms had one or several cows producing milk mainly for personal consumption.
Table 1.7: Temporary permissible levels (TPL)/action levels for radionuclides in foodstuff
after the Chernobyl accident in the USSR (IAEA, 2006), Bqkg-1
FOODSTUFF
Date
May 06,
1986 for
131
I
May 30, 1986
for total beta
activity
Dec 15, 1987
for 134+137Cs
Oct 06, 1988
for 134+137Cs
Jan 22, 1991 for
134+137
Cs and 90Sr
Drinking water
3700
370
20
20
20
Bread and bakery
products, cereals
370
370
370
370
Milk
3700
370
370
370
370
Condensed milk
18500
1110
1110
1110
Sour cream
18500
3700
370
370
370
Cheese
74000
7400
370
370
370
Butter
74000
7400
1110
1110
370
Meat and meat
products
3700
1850
1850
740
Fish
37000
3700
1850
740
Vegetables
3700
740
740
600
Leaf vegetables
37000
3700
740
740
600
Fresh fruit and
berries
3700
740
740
600
Dried fruits and
berries
3700
11100
1110
2900
Fresh mushrooms
and wild berries
18500
1850
1480
Dried mushrooms
11100
7400
Baby food
370
370
185
Radiation monitoring of the agricultural production contamination at large milk plants and
in collective farms was arranged in 1–2weeks after of the accident had occurred:
19
urban population was mainly protected against consumption of radioactive
contaminated agricultural products, especially milk, through the distribution network
(foodstuffs were delivered from clean regions);
rural population that had cows in private farms was not informed about
contamination of milk with 131I, that resulted in high doses to the thyroid gland and
increase of thyroid cancer morbidity in children after the accident.
In the first few days after the accident, countermeasures were largely directed towards
collective milk and few private farmers were involved. Information on countermeasures for milk
was confined to managers and local authorities and was not distributed to the private farming
system of the rural population. This resulted in limited application of the countermeasures with
some delay, especially in rural settlements for privately produced milk, resulting in a low
effectiveness in some areas (Ministry of Ukraine of Emergencies, 2011).
In the first weeks after the accident the main aim of the application of countermeasures in
the USSR was to decrease the 131I activity concentrations in milk or to prevent contaminated milk
entering into the food chain. To achieve this the following measures were recommended (IAEA,
1994):
radiation monitoring and subsequent rejection of collective milk at processing plants
in which 131I activity concentrations were above action levels (3700 Bql-1 at that
time).
processing rejected milk (mainly converting milk to storable products such as
condensed or dried milk, cheese or butter) in order to decrease the 131I activity due to
its radioactive decay (T1/2=8 day).
exclusion of contaminated pasture grasses from animals diet by changing from
pasture to indoor feeding with uncontaminated feed.
Table 1.8: Current non-emergency permissible levels of specific activity (Bq kg-1) of cesium
radionuclides in food products adopted after the Chernobyl accident (IAEA, 2006) and after the
Fukushima accident.
Country
Codex
Alimentarius
Commission
(international
trade)
EU
Belarus
Russia
Ukraine
Japan
Year of adoption
1989
1986
1999
2001
1997 and 2006
2012
Milk
1000
370
100
100
100
50
Infant food
37
40–60
40
Bread, flour, cereals
600
40
40–60
20–50
100
Meat and meat
products
180–500
160
200
Dairy products
50–200
100–500
100
Fish
150
130
150
Vegetables, fruits,
potato, root-crops
40–100
40–120
40–70
Fresh wild berries and
mushrooms
185–370
160–500
500
Dried wild berries and
mushrooms
2500
2500
2500
20
Due to the feeding of animals with "clean" fodder the 137Cs content in cattle meat would
reduce to permissible levels 1–2 months after the beginning of the countermeasure implementation.
However, this countermeasure was not in widespread use at this stage, partly due to a lack of
uncontaminated feed at this early time in the growing season (there was no additional reserve of the
clean fodder) (Ministry of Ukraine of Emergencies, 2011).
Current non-emergency national Permissible Levels for foodstuffs, drinking water and wood
in Belarus, Russia and Ukraine are comparable and all of them are substantially lower than the EU
maximum permissible levels (except for dried wild berries and mushrooms) (Table 1.8). Higher
permissible levels in the EU are caused by a small (insignificant) part of products from Belarus,
Russia and Ukraine in the ration of Europeans.
The Permissible Levels of 90Sr in foodstuffs in Belarus, Russia and Ukraine are lower than
those for 137Cs: 3.7–25 Bql-1 for milk, 11–40 Bqkg-1 food grain, 1.85–5 Bqkg-1 for bread, 1.85–
5 Bqkg-1 for infant food etc.
After the Chernobyl accident non-emergency permissible levels were accepted only 11 years
after the accident. In Japan they were accepted after 1 year. The reason for this was that these two
accidents differ in their extent, levels of radioactive contamination of products, dynamics of the
decrease of radioactive contamination of vegetation in the conditions of different soils and climate,
and also by the countermeasures that have been used, or not. The main reason for high levels of
radioactive contamination of products in Belarus, Russia and Ukraine was the extensive system of
agricultural production. In Japan the radioactive cesium content in local animal products had not
already exceeded the permissible levels just in a year after the accident because of the intensive
system of agricultural production and the use of imported feed for animals from other countries. For
example, in Ukraine after the Chernobyl accident the level of internal exposure to the population
was higher than the level of external exposure due to consumption of radioactively contaminated
food products (Likhtarev, et al., 2012, 2013). In contrast, in Japan the level of external exposure to
the population after the accident at the Fukushima NPP was higher than the level of internal
exposure because of the low content of radionuclides in food products.
1.3. Overview of Protective Action Levels after the nuclear disasters
Different radionuclides are especially relevant from a health perspective. After the Chernobyl
accident, radiation levels were dominated by 137Cs and 90Sr which are both beta-emitters, 137m Ba - a
gamma-emitter, and 238,239,240Pu with 241Am, which are alpha-emitters. External dose rate depends on
the density of the contamination of territory with 137Cs. Internal dose is formed by the consumption of
137Cs and 90Sr with food and water. Inhalation of alpha-emitting radionuclides (238,239,240Pu and 241Am)
with contaminated air is the main source of internal radiation dose.
To protect human health from radiation exposure, actions need to be taken to reduce or
shield people from exposure, remove them from exposure or limit the period of their exposure.
Depending on the radionuclide, different protective measures are needed at different times.
Protective Action Levels refer to the exposure levels used to trigger the deployment of an
emergency measures.
On the basis of the Basic Safety Standards (IAEA, 1996b), based on the experience of the
Chernobyl accident (IAEA, 1992), ten years after the accident Radiation Safety Standards were
developed and enacted in the three most affected countries (RSS-2000, 2000; RSS-99/2009, 2009;
RSSU-97, 1998).
According to the Radiation Safety Standards of Ukraine (RSSU-97, 1998) any intervention
(countermeasures) after a radiation accident may be qualified as unjustified, justified and
unconditionally justified.
The intervention is not justified if the benefit for people health from the countermeasure is
equal to or less than the amount of damage caused by this intervention.
The interventions are qualified as unconditionally justified if the averted dose value is so
much that the benefit to health from such intervention is definitely higher than the amount of
21
damage which this action causes. Certainly such urgent interventions should be qualified as justified
if by the implementation of these interventions it is possible to avoid the threat of acute clinical
manifestations of radiation damage: radiation sickness, radiation skin burns, radiation-induced
thyroiditis, etc., and other deterministic (tissue) effects (> 100 mSv).
Between the border of justified interventions on one side and unconditionally justified
interventions on another there is a range of values of averted doses which imply that
countermeasures must be optimized before the implementation.
At the initial (acute) phase of the accident the main and most effective urgent and immediate
countermeasures are: shelter, evacuation, iodine prophylaxis, limiting of population outdoor activity
(Table 1.10), and temporary ban on the consumption of certain locally produced foods and on the
use of water from local sources (RSSU-97, 1998). After the Chernobyl accident the mandatory
evacuation of population was carried out when the expected dose was higher than 100 mSv in the
first year. According to the current Radiation Safety Standards of Ukraine (RSSU-97) a mandatory
evacuation must be carried out when the averted dose in the first 2 weeks after the accident is higher
than 500 mSv (Table 1.10). Thus, after the Chernobyl accident the regulations for the evacuation of
population were not significantly tightened in case of nuclear and radiation accidents.
The long-term countermeasures that can be performed in the early and late phases of the
accident are (Table 1.11):
temporary evacuation;
resettlement (for permanent residence);
limiting of the consumption of radioactively contaminated water and foods;
decontamination of the territories;
different agricultural countermeasures;
other countermeasures (hydrological, including flood control, limitations related to
forest management, hunting, fishing, etc.).
Any long-term countermeasures must be stopped when the dose estimates indicate that
further continuation of these countermeasures is unjustified because the residual dose level is lower
than the acceptable level. The population resettlement after the Chernobyl accident was carried out
under the levels of terrestrial contamination with radionuclides and radiation doses to the population
which were lower than that ones used according to the current Radiation Safety Standards of
Ukraine (RSSU-97, 1998) — Table 1.11.
Table 1.10: The values of averted doses used for the classification of urgent
countermeasures as justified and unconditionally justified (RSSU-97, 1998)
Countermeasures
Averted dose per the first 2 weeks after the accident for
Justified countermeasures
unconditionally justified
countermeasures
mSv
mGy
mSv
mGy
For whole
body
For
thyroid
For
skin
For whole
body
For
thyroid
For
skin
Shelter
5
50
100
50
300
500
Evacuation
50
300
500
500
1000
3000
Iodine prophylaxis: children
adults
-
1
50f
200f
-
-
-
-
200f
500f
-
-
Limiting of population outdoor
activity: children
adults
1
2
20
100
50
200
10
20
100
300
300
1000
f The expected dose of the internal exposure by iodine radioisotopes received by the organism during the first
two weeks after the accident. 22
Table 1.11: The lower limits of criteria used for the qualification of countermeasures as
justified, and levels of these criteria used for the qualification of countermeasures (including
resettlement) as unconditionally justified right after the Chernobyl accident / and now (RSSU-97,
1998) - Table 1.5 (Verkhovna Rada of Ukraine. On the Legal, 1991)
Criteria for decision
Lower limits of
the justification
Unconditionally
justified intervention
levels and action
levels
Averted dose for the whole period of the
resettlement
g
, mSv
70/200
350/1000
Averted dose per the first year (12 month) after the
accident
g
, mSv
50
100/500
Summarized averted dose per whole period of the
temporary resettlement
g
, mSv
100 1000
Radionuclide contamination density by long-lived
radionuclides, kBq·m2
137
Сs
185/400
555/4000
90Sr
5.5/80
111/400
α- emitting (238,239,240Pu, 241Am, and others)
0.37/0.5
3.7/4
According to the RSSU-97 the following summarized levels of external and internal
radiation are acceptable (RSSU-97, 1998):
1 mSv per year for chronic exposure of more than 10 years;
5 mSv in total for the first two years;
15 mSv in total for the first 10 years.
These values must be taken into account when the measure (boundary) of the communal
accident is being determined.
Temporary resettlement and evacuation implies population displacement from the accident
area for a limited period of time. The evacuation is carried out as an emergency countermeasure in
the early phase of the accident. At the same time temporary resettlement is carried out only after a
detailed study of the radiation environment (usually in the middle and even later phase).
The criterion for evacuation after the Chernobyl accident was an expected effective dose
during the first year after the accident (from April 26, 1986 until April 25, 1987) of 100 mSv (see
paragraph 1.2 above). Since 1991 the criterion for the resettlement was the average annual effective
dose of 1–5 mSv (Table 1.5). Now according to the RSSU-97 the lower limit of the justified
evacuation corresponds to higher levels of radiation exposure, and it is more than the averted dose
of 50 mSv in the first 2 weeks after the accident (Table 1.10). Therefore, the level of the
unconditionally justified evacuation corresponds to the averted dose of 500 mSv in the first 2 weeks
after the accident. According to the RSSU-97 the criteria for resettlement of population is the
averted dose of 50–500 mSv during the first year (12 months) after the accident (Table 1.11). In
1986 the averted dose in Chernobyl due to resettlement was in this range (100 mSv). In 1991 the
values of the permitted average annual effective dose of 5 mSv for an obligatory resettlement and
1 mSv for a voluntary resettlement were enacted in the three countries. These values were
significantly lower than the limits established by the RSSU-97 (Table 1.9, 1.10). At the same time
the permitted contamination densities of 137Cs (of 555 and 185 kBqm-2), 90Sr (of 111 and 5.5
kBqm-2) and 238240Pu (of 3.7 and 0.37 kBqm-2) (Table 1.5) which were used as criteria for the
g It needs for the forecast of the changes in the radiation situation 23
resettlement in 1991 and also for the division of radiation zones do not correspond to levels of the
justified intervention according to RSSU-97 (Table 1.11).
In the case of a radiation accident the limitations on food and water consumption may be
accepted in order to reduce the internal dose (Table 1.12). Action levels (Bqkg-1) for radionuclides
in food products adopted in Europe, by IAEA, in Ukraine and in Japan after the accident are rather
close. In response to the accident of Fukushima Daiichi NPP, the government of Japan has set
provisional regulation values of radionuclides in foods. The temporary permissible level for 131I in
milk in the USSR after the Chernobyl accident was 10 times higher. Based on the Chernobyl
experience of the application of countermeasures, two action levels are specified for the radiation
accident situations in Ukraine.
Table 1.12: Action levels (Bqkg-1) for radionuclides in food products adopted after nuclear
and radiological accidents in Europe (EC, 1986), by IAEAh (IAEA, 1994), in Ukraine (RSSU-97,
1998 and after Chernobyl in 1986 Table 1.7 ) and in Japan after the accident of Fukushima
Daiichi NPP
Radionuclide group
Activity concentration (Bqkg-1or Bql-1)
baby foods
dairy produce
other foodstuffs
Isotopes of I, especially 131I
EC
IAEA
Ukraine (RSSU
-97)
Ukraine (after Chernobyl)
Japan (after Fukushima)
150
100
100–200
500
100
400–1000
3700i
300
i
2000
1000
800–2000
37000
2000
All other nuclides with half-life greater than 10 days,
especially
134Cs and 137
Cs
EC
IAEA
Ukraine (RSSU
-97)
Ukraine (after Chernobyl)
Japan (after Fukushima)
400
1000
1000
1000
100–400
370
200
1250
1000
200–800
370–3700
500
Isotopes of Sr, especially 90Sr
EC
IAEA
Ukraine (RSSU -97)
75
100
5–50
125
100
20–200
750
100
40–400
Alpha emitting isotopes, especially 239Pu and 241Am
EC
IAEA
1
1
20
1
80
10
1.4. Proposed changes to Protective Action Levels and analysis of those
changes
According to the latest International Basic Safety Standards (IAEA, 2011) for optimization
of protection and safety in emergency exposure situations and in existing exposure situations
h These levels apply to national control where alternative food supplied are available: if this is not the case,
higher levels may applied
i and for drinking water 24
reference levels of doses are used, for avoiding deterministic effects (>100 mSv) and reducing the
likelihood of stochastic effects (<100 mSv) due to public exposure.
The reference levels are not dose limits and they are established or approved by the
government, the regulatory body or another relevant authority.
Any situation that results in a dose of greater than 100 mSv being incurred acutely or in one
year would be considered unacceptable, except under circumstances relating to exposure of
emergency workers. Reference levels of 20–100 mSv would be used for the residual dose after a
nuclear or radiation emergency to reduce the risk of stochastic effects (Table 1.13).
Reference levels of 1–20 mSv would be used for optimization of radiation protection of
population in existing exposure situations (for Chernobyl now) to levels that are as low as
reasonably achievable, as well as economic, societal and environmental factors being taken into
account. The minimum value of the reference level of 1 mSv is lower than the annual dose received
from natural sources (the worldwide average annual radiation dose from natural sources, including
radon, is 2.4 mSv (UNSCEAR, 2000)). While this optimization process is intended to provide
optimized protection for all individuals subject to exposure, priority shall be given to those groups
for whom residual dose exceeds the reference level. All reasonable steps shall be taken to prevent
doses remaining above the reference levels. Reference levels shall typically be expressed as an
annual effective dose to the representative person in the range of 1–20 mSv.
Table: 1.13: Generic criteria for protective actions and other response actions in emergency
exposure situations to reduce the risk of stochastic effects (IAEA, 2011)
Generic criteria
Examples of protective actions and other response
actions
Projected dose that exceeds the following generic criteria: Take urgent protective actions and
other response
actions
50 mSv for Thyroid in the first 7
days
Iodine thyroid blocking
100 mSv in the first 7 days
Sheltering; evacuation; decontamination; restriction of
consumption
of food, milk and water; contamination
control;
public reassurance
Projected dose that exceeds the following generic criteria: Take protective actions and other
response actions at early stage
100 mSv per annum
100
mSv for Fetus for the full
period of in utero
development
Temporary relocation; decontamination; replacement
of food, milk
and
water; public reassurance
The annual effective dose for a representative person (a critical group) is the average dose
for 10 % of the most exposed people who have received the highest doses of external and internal
exposure. In the later phase of the liquidation of the Chernobyl accident in the settlements, the
effective dose of external and internal exposure for a representative person was respectively 1.8
times and 3 times (IAEA, 2006) higher than the average dose for the population of the settlement.
Therefore, the limit of average annual effective dose adopted in Ukraine for population radiation
exposure (AAED) of 1 mSvy-1 for the third Zone of a guaranteed voluntary resettlement
(Verkhovna Rada of Ukraine. On the Legal, 1991) corresponds to an annual effective dose to the
representative person of 23 mSv. Using the reference levels of an annual effective dose to the
representative person of 1 mSvy-1 the average annual effective dose for the population in a
settlement will be 0.30.5 mSv;is equal to or even lower than the dose in the 4th Zone of an
enhanced radioecological monitoring, which was liquidated on 28.12.15 (Verkhovna Rada of
Ukraine. On Amendments, 2015).
According to the dosimetry certification in 2011-2012 only in 25 settlements the AAED was
higher than 1 mSv, in 60-101 settlements the AAED was 0.5-1 mSv and in less than 370 settlements
the AAED was 0.3-0.5 mSv (Lihtarov, et al., 2012; Lihtarov, et al., 2013). Therefore, the use of
reference levels of an annual effective dose for the representative person of 1 mSv will result in the
25
significant increase of the area of the contaminated territories according to the Law of Ukraine: "...,
in Ukraine, the territories radioactively contaminated as a result of the Chernobyl accident, are the
areas with persistent contamination of the environment by radioactive substances with levels above
those existed before the accident and which can result in population exposure dose more than
1.0 mSv per year, taking into account climatic and complex ecological characteristics of these
territories; and where the level of contamination requires implementation of measures to protect
the population from radiation, in addition to other special interventions aimed to limit additional
population exposure caused by the Chernobyl accident, as well as to ensure normal economic
activity of population" (Verkhovna Rada of Ukraine. On the Legal, 1991).
1.5. Radiation protection of environment
Recently the risk assessment of the exposure not only for humans but also for other
organisms has become very relevant. The main paradigm of radioecology is based on the statement:
"If humana are protected, other biological objects are protected too", but the question of the legality
of this paradigm is being raised (ICRP 103, 2007).
The general conclusion from the Environmental Protection from Ionizing Contaminants
(EPIC) database is that the threshold for deterministic radiation effects in wildlife lies somewhere in
the range of absorbed dose rate 0.5–1 mGyd-1 (the predicted no effect dose rate PNEDR) for
chronic low linear energy transfer radiation (IAEA, 2006). Quantitative dose rate/effect correlations
were established for morphological and cytogenetic changes in Scots pine trees exposed to chronic
irradiation (Yoschenko, et al., 2011; Watanabe, et al., 2015). Dose rate of 0.02 mGyd-1 and
1 mGyd-1 caused disappearance of the apical dominance in 10% and 50% of the sampled trees,
respectively (Fig. 1.6). This morphological effect and related suppression of development can, to a
certain extent, affect evolution of specific ecosystems in the Chernobyl Exclusion Zone, which
possibly has to be taken into consideration for establishment of the PNEDR values and similar
values for terrestrial ecosystems.
Different biological effects and changes in species richness of insects and animals in the
ChEZ have also been found (Møller and Mousseaue, 2007, 2009, 2011; Møller, et al., 2005, 2013;
Mousseaue and Møller, 2014). These effects and changes were caused by both the radiation
influence and changes in the environment because of the population evacuation, and the termination
of traditional economic activities in the ChEZ (Smith, 2008), and it requires further research.
The danger of the revealed radiobiological effects at the population level is still unclear, and
at the present time this question requires further research.
There were no standards of radiation protection of the environment when the Chernobyl
accident occurred. Now Biota Working Group of IAEA Environmental Modelling for Radiation
Safety and ICRP Committee 5 task group are developing such standards for the reference species of
organisms.
26
Fig.1.6: The morphological changes (the apical dominance) in Scots pine trees
References on ”Red forest” site (the absorbed dose up to 10 Gy per year now) (Ministry of Ukraine
of Emergencies, 2011; Yoschenko, et al., 2011 ) in ChEZ (a) and Japanese fir trees around the
Fukushima Daiichi Nuclear Power Plant (Watanabe, et al., 2015) (b)
1.6. Proposed changes to Protective Action Levels
During the regional Workshop on Transition of Areas Affected by the Chernobyl Accident
to Normal Radiological Conditions and Resumption of Economic activities in Abandoned Areas
(Vienna, October 7–8, 2015) Ukrainian national experts recommended the following changes to
Protective Action Levels in Ukraine for the existing exposure situation in order to improve radiation
protection of the population (Kashparov, V.A. 2015):
1. From the experience and according to the current situation and to the recommendations of the
BSS to use the level of 1 mSvy-1 as a reference level of the representative person exposure for the
post-Chernobyl situation and existing exposure.
2. Use the reference level of the representative person exposure of 1 mSvy-1 as a basic criterion of
the radiological classification of the territory instead of the terrestrial contamination density with
radionuclides for the post-Chernobyl situation.
3. The measures on radiation protection of population and other special interventions aimed to
limit the additional exposure of population of more than 1 mSvy-1 caused by the Chernobyl
accident and interventions aimed to ensure a normal economic activity should be considered
priorities.
4. Optimize permissible levels/action levels for radionuclides in foodstuff/commodities and the
system of radiation monitoring.
27
2. Chernobyl’s Contamination 30 years later with sections on food,
environment (ground and wildlife) and water
Thirty years after the Chernobyl accident the activity of 90Sr and 137Cs decreased by a factor
of 2. By 2016 (when about one half-life of 137Cs had elapsed) the total area with a contamination
density of 137Cs above 1 Cikm-2 (37 kBq m-2) in Belarus, Russia and Ukraine will be respectively
1.6, 2.9 and 2.7 times smaller. In 2046 (when 2 half-lives of 137Cs have elapsed) the areas with a
contamination density of 137Cs above 37 kBqm-2 (it is a legally defined bottom criterion of the
radioactive terrestrial contamination after the Chernobyl accident) in the three countries in
proportion to 1986 will be respectively 2.4, 5 and 7 times smaller (The Atlas, 2009; CD, ATLAS,
2008; Ministry of Ukraine of Emergencies. 2011).
At the present time the contamination with 137Cs of agricultural products has decreased by
factors of tens and hundreds due to fixing of the different soils, but herewith the content of
radioactive cesium in the non-wood forest products (mushrooms, berries, meat of wild animals) is
several times greater than it was earlier. The exceeding of the permissible content of 137Cs is
observed in milk and meat from cattle (PL-2006) grazed on peat soils and non-wood forest products
(Kashparov, et al., 2011; UIAR, 2015; Maloshtan, et al., 2015).
Throughout the period following the accident the increase of 90Sr bioavailability is occurring
due to the leaching of 90Sr from fuel particles, and now it has achieved its maximum value (half-life
of fuel particles in soils are 2–14 years). As a result of this the 90Sr content in an alimentary grain
and firewood in the near 60 km zone of the accident has been increasing during the last 15 years.
Now this parameter has achieved its maximum value and exceeds hygiene standards (Kashparov, et
al., 2013; Otreshko, L.N., et al., 2015).
During the time period after the accident, as a result of radioactive decay the activity of the
238Pu (T1/2=87.7 year) alpha-emitting radionuclides has decreased by 20%, and the activity of 239Pu
(T1/2=24100 year) and 240Pu (T1/2=6563 year) have barely changed. As a result of the radioactive
decay of the beta-emitting 241Pu (T1/2=14.4 year) and the 241Am (T1/2=432.8 year) radionuclides
have been accumulated and their activity has been increasing. At the present time the activity of
241Am is higher than the activity of 238+239+240Pu by 33% and it will be increasing during the next 50
years by 16%. After this the activity of 241Am with a half-life of 432.8 years will slowly decrease.
The increase of the radioactive contamination of 241Am in the environment due to the
radioactive decay of 241Pu has no significant effect on the radiological situation (total alpha-emitted
radionuclides activity) because of future insignificant increase (<20%) and simultaneous decrease
of 238Pu (T1/2=87.7 year) activity (Fig. 2.3).
High levels of contamination of the 10 km Exclusion Zone by the long-lived 239Pu
(T1/2=24100 year), 240Pu (T1/2=6563 year) and the presence of dangerous radiological objects
(including radioactive waste disposal, processing of radioactive waste, storage of nuclear fuel,
Unit 4 of the ChNPP) make the returning of population and inhabitation of these areas impossible
for tens of thousands of years (Kashparov, et al., 2015a). In the Chernobyl Exclusion Zone
numerous morphological, cytogenetic and biochemical changes in plants, insects and animals are
observed even at relatively low dose loads (from 0.02 mGy·d-1) (Geraskin, et al., 2003; Ministry of
Ukraine of Emergencies, 2011; Yoschenko, et al., 2011; Kashparov, et al., 2012; Møller and
Mousseaue, 2007, 2009, 2011; Møller, et al., 2005, 2013; Mousseaue and Møller, 2014).
The results of active experiments and mathematical modelling show that fires in the
Chernobyl Exclusion Zone don’t significantly increase the secondary contamination of the
territories outside the ChEZ and the exposure doses to population, see paragraph 2.3 (Kashparov, et
al., 2000;Yoschenko, et al. 2006a; Yoschenko, et al., 2006b; Khomutinin, et al., 2007; Kashparov,
et al., 2015b).
For everywhere outside the ChEZ the content of radionuclides in the groundwater and
surface water is within the hygiene standards for drinking water (Ministry of Ukraine of
Emergencies, 2011). In the Exclusion Zone around the places of temporary localization of
radioactive wastes the migration of 90Sr and plutonium radionuclides to groundwater from landfills
28
was found (Bugai, et al., 2012; Levchuk, et al., 2012). After the reduction of the water level in the
cooling pond of the Chernobyl Nuclear Power Plant by 3.5 m during the past year (pumps for filling
the cooling pond have not worked since September 2014) the content of 90Sr and 137Cs in the water
of this pond is a few Bq·l-1. There is a risk of catching fish containing 90Sr and 137Cs above the
permissible level (150 Bqkg-1 and 35 Bqkg-1) in the Kiev reservoir near the borders of the ChEZ,
but only 5 from 100 caught fishes will be contaminated.
There is no such danger in the rest of Ukraine with the exception of certain closed water
bodies with low potassium content in the water, where the content of 137Cs in fish can be several
times higher than the Permissible Level -2006 (Khomutinin, et al., 2011; Khomutinin, et al., 2013;
Khomutinin, 2014).
At the present time there are no official proposals to lift the Exclusion Zone around
Chernobyl Nuclear Power Plant.
There are different opinions about the future of the Exclusion Zone in Ukraine (SAUEZ,
2015a.): not to change anything; to create a Biosphere Radiological Reserve; and to create a Special
Zone of Radiation Danger of the ChNPP (a zone of special industrial use with the exceptional
"lifelong" status of the unfitness for population inhabitation).
2.1. Evacuation Zones Around Chernobyl and general evacuation policies
At the present time and over the next ten years in the Chernobyl Exclusion Zone the
radiological threat will be posed mainly by medium-lived and long-lived radionuclides: 90Sr
(T1/2=29 y), 137Cs (T1/2=30.2 y), 238Pu (T1/2=87.7 y), 239Pu (T1/2=24100 y), 240Pu (T1/2=6563 y),
241Am (T1/2=432.8 y).
The ChEZ is also called the «30-km zone». The most contaminated areas around the
Chernobyl nuclear power plant with a special mode of the admission (fenced, with additional
checkpoint) is also called the 10-km zone or Zone No.1, however its shape is not round but
elongated along the spread of the radioactive contamination in the western direction (Fig. 2.1)..
According to the Laws of Belarus, Russia and Ukraine (see chap. 1) the areas rendered
hazardous due to radiation are territories where the average annual effective dose of population
radiation exposure is greater than 5 mSv or the contamination density of 137Cs > 555 kBq·m-2, 90Sr
> 111 kBq·m-2, plutonium isotopes > 3.7 kBq·m-2. Habitation by humans and production of
agricultural and other products is forbidden in these areas. By the Law of Ukraine (Verkhovna Rada
of Ukraine. On the Legal, 1991) it is not indicated exactly what plutonium isotopes should be
considered (alpha-emitting 239240Pu isotopes have been assumed). It causes contradictions in the
interpretation of boundaries in the radioactive zones, because now the activity of beta-emitting 241Pu
(T1/2=14 y) is more than 10 times higher than the activity of 238240Pu and the contour line of the
territory where contamination density of 241Pu>3.7 kBq·m-2 extends beyond the ChEZ territory
(Ministry of Ukraine of Emergencies, 2011).
The analysis of the border of the hazardous areas due to the radionuclides contamination
(Table 1.5) shows that after 500 years the contamination density of 238-240Pu will be higher than 3.7
kBq·m-2 in the 10-km zone around the ChNPP (about 450 km2) and therefore the 10-km zone will
not be habitable- Fig. 2.1 (Kashparov, et al., 2015a).
The maps with the expected effective radiation doses for the representative person in 2016
and 2516 show that levels of radiation higher than 1 and 5 mSv·y-1 are now beyond the borders of
the 30-km and 10-km ChEZ, respectively (Fig. 2.2). Probably, even in 500 years in the south
direction the effective dose will be higher than the dose limit of 1 mSv·y-1 (Fig. 2.2) because of
possible ingestion of 239240Pu and 241Am with contaminated soil (unwashed vegetables, hands, etc.).
Even in 500 years within the area of 500 km2 the radiation level may be higher than the dose limits
for the representative person.
29
a
b
Fig. 2.1: The terrestrial contamination density of 238240Pu in the ChEZ: a – in 2016 and b – in 2516.
30
a
b
Fig. 2.2: Expected effective doses for the representative person in 2016 (a) and 2516 (b)
31
In the future the increase of 241Am activity due to the radioactive decay of 241Pu will not
increase the Equivalent Dose Rate and inhalation threat significantly in the ChEZ
territory (Fig. 2.3).
Fig. 2.3: The relative contribution to:
a – the formation of the equivalent dose of 137Cs and 241Am (the contribution of 241Am to the EDR
formation at present time is accepted as 1 unit);
b – the relative activity of alpha-emitting radionuclides (in proportion to the activity of the long-
lived 239 + 240Pu radionuclides) in the fuel component of the Chernobyl radioactive fallout
At present time almost throughout the ChEZ territory the 137Cs content in wild mushrooms
and berries may exceed the PL-2006 standards (500 Bqkg-1 for fresh and 2500 Bqkg-1 for dry
weight) (PL-2006, 2006). In the 10-km Zone and “Cesium spot” beyond the Zone near the
Vesnyanoe settlement (Fig.1.4a) the 137Cs content in milk and beef may also exceed the standards in
an area of about 440 km2. Nowadays the 90Sr content in grain may exceed the hygiene standards for
alimentary grain (20 Bq·kg-1) throughout the ChEZ territory and outside the CheZ in adjacent
regions (Kashparov, et al., 2013; Otreshko, L.N., et al., 2015). In 100 years in 2116 the
contamination by 137Cs above the PL-2006 standards will be observed only within the 10-km Zone
32
in an area of about 460 km2, and the 90Sr content may exceed permissible levels in grain outside this
zone on the total area of about 800 km2 (Fig. 2.4).
Fig. 2.4: Levels of 137Cs specific activity in milk (100 Bql-1) and mushrooms
(500 Bqkg-1), and 90Sr (20 Bqkg-1) in grain in the ChEZ in 2016 and 2116
The strictest requirements on the content of radionuclides in wood were established in
Ukraine for the specific activity of 90Sr in wood and brushwood (it is 60 Bq·kg-1) (SSSAR-2005,
2005). At the present time throughout the ChEZ territory the long-term production of firewood is
impossible (Fig. 2.5).
2.1.1. Special Zone of Radiation Danger (SZRD) of the ChNPP
Thus, around the ChNPP in the 10-km ChEZ long-term stable contamination with long-lived
alpha-emitting radionuclides has occurred. These conditions will not allow population to live there
in the foreseeable future. Taking into account the existing legislative framework of Ukraine with the
international safety standards and documents of the European Union it is being planned to create a
Special Zone of Radiation Danger (SZRD) of ChNPP (a zone of special industrial use with the
exceptional "lifelong" status of unfitness for habitation) on this territory. The rest of the ChEZ
where the return of population and the maintaining of traditional economic activities are not
planned should be a buffer zone between the SZRD of ChNPP and the territory where habitation
begins again (Kashparov, et al., 2015a). This is the official position of the ChNPP administration in
light of the results of the analysis of the radiation situation in the ChEZ. The possibility of the
creation of a radio-ecological biosphere reserve in this buffer zone, as in Belarus, and other variants
are also considered. The future status of this territory has not been determined yet.
33
a
b
Fig. 2.5: The 90Sr content in the wood in 2016 (a) and in 2116 (b)
>60 Bqkg-1
<60 Bqkg-1
The results of the analysis of radionuclides terrestrial contamination (Fig. 2.1),
contamination of products (Fig. 2.4, 2.5) and dose assessment (Fig. 2.2) show that the main criteria
for the SZRD location is the contamination density of the long-lived alpha-emitting radionuclides of
239-240Pu and 241Am (more than 3.7 kBq·m-2) and the expected average annual doses of radiation
exposure for the representative person caused by these radionuclides (more than 5 mSv) - Fig. 2.1,
2.2. These criteria are also used for the planning of the sites of placement of radiation-dangerous
objects (including, radioactive waste disposal, processing of radioactive waste, storage of nuclear
fuel, and 4th of ChNPP) and sites of the potential location of a deep geological storage of
radioactive wastes in the southern and western part of the ChEZ. In this regard the borderline of the
SZRD should lie within the contour line of the terrestrial density of the contamination by
238+239+240Pu at the level of 3.7 kBq·m-2 (with a probability of 90%) and within existing boundaries
of the ChEZ (Fig. 2.6) (Kashparov, et al., 2015a).
34
Fig. 2.6: The boundaries of the contamination density of 238+239+240Pu on the level of 3.7 kBq m2 in
the ChEZ in 2016 and 2516 as the main criteria for the SZRD location.
2.1.2. Biosphere Radiological Reserve in ChEZ
There are different opinions about the future of the Exclusion Zone in Ukraine (SAUEZ,
2015a.): not to change anything; to create a Biosphere Radiological Reserve (Fig.2.7); to create a
Special Zone of Radiation Danger of the ChNPP (a zone of special industrial use with the
exceptional "lifelong" status of the unfitness for population inhabitation). In order to prepare
documents needed for the establishing of the Chernobyl Biosphere Radiological Reserve (ChBRR)
a special group within the Ministry of Environment was created. It was proposed by this group that
the boundary of the ChBRR beyond the ChEZ in the South direction should be extended (fig.2.7a)
((Bondar, et al., 2013). Currently, the Ministry of Environment of Ukraine has proposed to reduce
the area of anthropogenic impact and combine the borders of the ChBRR and ChEZ (fig.2.7b)
(Ivanenko, 2015).
35
a
b
Fig.2.7: The previous proposals for functional zoning of the ChBRR: a proposal of Bondar et al.,
2013 and b official proposal of the Ministry of Ecology and Natural Resources of Ukraine
(Ivanenko, 2015)
36
2.2. Proposals to lift evacuation zones around Chernobyl
At the present time there are no official proposals to lift ChEZ around Chernobyl.
According to the data of the dosimetry certification of Ukraine in 2011 and 2012 the average
annual effective dose was higher than 1 mSv only in 25 settlements (Fig. 2.8) (Lihtarov, I.A., et al.
2012; Lihtarov, I.A., et al. 2013). According to the Law only these residential settlements should be
designated to the radioactively contaminated areas and protective measures to reduce radiation
exposure to the population must be carried out in these settlements. In these critical settlements
where the average annual effective dose (AED) is higher than 1 mSv internal exposure is caused
mainly by the consumption of local milk (Fig. 2.8b). The application of protective
measures/countermeasures such as the radical improvement (creating highly productive artificial
pastures) of fields or the use of a special sorbent for cows (ferrocyn) with a reduction factor
(radiological efficiency) of 3 allows the 137Cs content in milk to be reduced below the permissible
level (100 Bq·l-1) and the dose of radiation exposure below 1 mSv·y-1 in nearly all settlements.
Unfortunately, since 2009 the protective measures to reduce radiation exposure to the population
have not been applied in Ukraine (Ministry of Ukraine of Emergencies, 2011).
a
b
Fig. 2.7: The previous proposals for functional zoning of the ChBRR: a — proposal of Bondar, et
al., 2013 and b — official proposal of the Ministry of Ecology and Natural Resources of Ukraine
(Ivanenko, 2015)
37
On December 28, 2014 in Ukraine the 4th Zone of an Enhanced Radoecological Monitoring
that included 1290 settlements was abolished (Verkhovna Rada of Ukraine. On Amendments,
2015), although the criteria of the settlements attribution to other radioactively contaminated zones
were not changed. As a result of work of the UIAR in 2014 detailed maps of the contamination with
137Cs and 90Sr of the Ivankov district of Kyiv region were constructed (Fig. 2.9) and the average
levels of the radionuclide contamination of the settlements were determined (Table 2.1)
(Kashparov, et al. 2014). It was found that more than 10 settlements of the Ivankov district assigned
before December 28, 2014 to the 4th Zone of Radioactive Contamination (Table 2.1) had to be
redesignated to the 3rd Zone of a Guaranteed Voluntary Resettlement because of the density of the
90Sr contamination (that is higher than 5.5 kBq·m-2) from 1991 (Tabl1 1.5).
Fig. 2.9: Cartogram for density of soil contamination with 90Sr in Ivankov region near the ChEZ,
2014 (Kashparov, et al., 2014)
During the mapping of the density of the soil contamination with 90Sr and 137Cs in the
Ivankov region outside the ChEZ in 2014, separate "hot spots" with a size of several hectares and
high dose rate were revealed. In 1986 the military units that took part in the liquidation of the
consequences of the Chernobyl accident were situated in these areas. In these areas the dose rate
exceeded the background levels by factors of tens and hundreds because of the contamination of the
territory in 1986-1987 caused by decontamination of the equipment, etc. - Fig. 2.10 (Kashparov, et
al., 2014). At present there are no any restrictions to access such "hot spots" outside the ChEZ,
containing highly radioactive material. There are no danger warning signs in these areas, and they
can be freely accessed by the population, including children. For protection of the public, it is
necessary to identify and mark all of these "hot spots" through dedicated research of the territory
outside the ChEZ, where people reside. Danger warning signs should be installed; and
decontamination of the territory should be conducted if it is required.
38
Table 2.1: The terrestrial contamination density of 90Sr in the settlements of the 4th Zone of an
Enhanced Radioecological Monitoring abolished on 28.12.14 (Verkhovna Rada of Ukraine. On
Amendments, 2015), of Ivankov district of Kyiv region in 2014 (the criterion for the 3rd Zone of a
Guaranteed Voluntary Resettlement is 90Sr > 5.5 kBqm-2) (Kashparov, et al., 2014)
No
Settlement
Number of
analyzed samples
Terrestrial contamination density
Mean±STD, kBqm-2
Min–Max, kBqm-2
1
Domanovka
1
43.3
2
Zimovisсhe
3
7.5±3.5
4.3–11.3
3
Kovalevka
2
22.1±1.6
21.0–23.3
4
Leonovka
3
9.6±1.8
7.5–10.8
5
Malaia Makarovka
3
8.2±2.0
6.6–10.4
6
Novye Makalevichi
3
12.4±4.6
9.4–17.7
7
Pirogovichi
3
9.5±9.0
2.6–19.6
8
Potoki
1
6.2
9
Rusaki
4
14.6±7.8
6.5–23.1
10
Sosnovka
4
7.7±3.0
4.5–10.4
11
Teterevskoe
5
4.8±3.4
2.9–10.9
12
Fenevichi
7
8.3±2.9
3.8–11.6
13
Khocheva
2
28.5±10.9
20.9–36.2
14
Shpili
4
12.1±4.0
7.7–16.9
2.3. Risks of recontamination forest fire
In the period 1993–2013, more than 1100 wildfires of different kinds and scales were
officially registered in the ChEZ, including in the most contaminated 10-km zone. The most fire-
dangerous periods are April–May and August. The largest fires occurred on August 1992 in a total
area of 17 000 ha of meadows and forests, including a crown fire in the area of more than 5 000 ha
(Evangeliou, et al., 2015a).
In the absence of the traditional economic activity in the ChEZ during the last 30 years,
dangerous fuel material in the forests and meadows has accumulated intensively. Excessively high
density of plants in the pine forests throughout the ChEZ, a mixture of different tree ages, and the
presence of young trees on the edges of forests, all increase the risk of high-intensive, crown, and
extensive wildfires. The existing tools, structure and location of fire departments in the ChEZ are
insufficient to such a high risk of fire, as they do not guarantee a rapid response nor effective
firefighting in critical weather conditions. For example, in the ChEZ a fire department with two or
three old fire engines, with a limited amount of fuel and lubricant, and with 5–7 firefighters is
responsible for an area of more than 65 000 ha. At the same time outside the ChEZ every fire
department is responsible for an area that is about 15–20 times smaller. Besides this, about a third
of the territory of the ChEZ is not covered by fire detection (there are no fire lookout towers) and
almost 23 000 ha of forest is not reachable for fire engines and fire brigades (Evangeliou, et al.,
2015b). All of these factors cause a high risk of large-scale fires in the ChEZ. The largest of the
ChEZ fires after 1992 happened in the end of April 2015.
At the time of fire, high-temperature evaporation of radionuclides occurs and small-
dispersed radioactive aerosol appears due to ash-formation and radionuclide condensation on
various carriers. All these facts are accompanied by a rise of above-ground radionuclide
concentration in the air, up to hundreds and thousands of times higher than the normal levels
(Kashparov, et al., 2000; Yoschenko, et al., 2006a).
39
At the present time, large parts of the ChEZ territory are covered with forests, where
ordinary pine and birch trees prevail (64% and 23%, respectively). The part of flammable material,
which is burnt, depends on the type of fire and fire risk in various weather conditions, and varies
from 0% for wood to 97% for needles/leaves. During the forest fires up to 3–4% of the 137Cs and
90Sr and up to 1% of the Pu isotopes can be released from the forest litter. The released fraction of
the radionuclides during the forest fires may even be bigger if the source of release is a large-scale
and very intensive fire, since in this case a bigger burn-up of the combustible material can be
expected (Yoschenko, et al., 2006b). Experimental and calculated data demonstrate that, even under
the most unfavorable conditions, radionuclide resuspension during forest fires will not provide a
significant contribution to terrestrial contamination. Additional terrestrial contamination due to a
forest fire at a distance more than 100 m from the front of the fire can be estimated to be in the
range of 10-4–10-5 of its background value (Table 2.2, 2.3) (Kashparov, et al., 2000; Khomutinin, et
al., 2007; Yoschenko, et al., 2006a).
During the forest fire in the most contaminated areas of the Exclusion Zone (Fig. 2.10) the
additional radioactive contamination outside the ChEZ will be not significant and the expected dose
for personnel and population of the ChEZ will not exceed a few μSv (Table 2.2–2.4). Thus, the
radionuclide release outside the Exclusion Zone will be less than 1 percent of the radionuclide
content in the fire area (Table 2.4). The maximum doses of tens of μSv can be received by
firefighters (Table 2.3).
Fig. 2.10: Assessment of the effects of forest fires on the most contaminated areas near the
settlements: Vesniane (1), Krasne (2), Buryakivka (3), Chistogalivka (4), Kopachi (5) and Leliv (6)
40
Table 2.2: Estimates of the maximum radionuclide fallout density and the maximum doses
from radionuclide inhalation to the population of the settlements adjacent to the Chernobyl
Exclusion Zone (Khomutinin, et al., 2007)
The settlements adjacent to the ChEZ
(Distance from the fire)
Additional fallout density, Bq·m-2
Dose, µSv.
137Cs
90Sr
239+240Pu
Forest fire near settlement Buryakivka (3)
Nivetske (17 km)
0.4
0.3
0.00005
1.0
Cheremoshna (18 km)
0.6
0.3
0.00004
0.9
Forest fire near settlement Chistoalivka (4)
Cheremoshna (24 km)
0.4
0.2
0.00003
0.6
Nivetske (22 km)
0.5
0.2
0.00004
0.8
Forest fire near settlement Leliv (6)
Dytiatky (24 km)
0.1
0.1
0.00001
0.3
Table 2.3: Maximum values of terrestrial contamination density of radionuclides and
possible maximum values of doses received through the inhalation of radionuclides for personnel in
the Chernobyl Exclusion Zone and firefighters in the conditions of forest fire in the ChEZ
(Khomutinin, et al., 2007).
Distance from
the fire
Additional terrestrial contamination density,
Bq·m
-2
Dose, µSv
137Cs
90Sr
239+240
Pu
Forest fire near settlement Buryakivka (3)
Chernobyl (24 km)
0.2
0.01
0.00001
0.4
ChNPP (14 km)
1
0.5
0.0001
1.6
“Vector” (2 km)
2
1
0.0001
2.6
Firemen
22
Forest fire near settlement Chistoalivka (4)
Chernobyl (19 km)
1
0.4
0.00008
1.3
ChNPP (8 km)
4
2
0.0003
4.6
“Vector” (6 km)
3
1
0.0003
3.9
Firemen
40
Forest fire near settlement Kopachi (5)
Chernobyl (14 km)
1
0.6
0.0001
1.4
ChNPP (3 km)
4
3
0.0005
5.6
“Vector” (12 km)
1
0.8
0.0001
1.8
Firemen
24
According to the most conservative estimates the transfer of radionuclides outside the
Chernobyl Exclusion Zone as a result of large fires in April and August 2015 in the area of about
15 000 ha could cause the additional contamination of European territory outside the Exclusion
Zone of less than 10 Bq·m-2 for 90Sr and 137Cs (background level of global fallout before the
Chernobyl accident 12 kBqm-2) and 0.1 Bqm-2 for 238239Pu and 241Am (background level of
global 239Pu fallout is about 50 Bqm-2) (Evangeliou, et al., 2015b).
The effective dose of radiation for firefighting personnel in the ChEZ is formed of the
external irradiation from radionuclides found outside the human body (soil, litter etc.) plus internal
irradiation of the organism after radionuclide inhalation through respiratory organs, eyes and mouth.
41
For a wide range of forest fire scenarios related to the Chernobyl 137Cs radioactive fallout
outside ChEZ, the contribution of the inhalation dose to the total external dose (that is proportional
to the terrestrial density of the contamination of 137Cs) does not exceed several percent (Kashparov,
et al., 2000; Khomutinin, et al., 2007).
Table 2.4: Estimates of the maximum activity flux outside the 30-km zone and the
maximum possible dose from radionuclide inhlalation at the closest point of the zone border
(Khomutinin, et al., 2007).
Location (distance to the closest
point of the 30-km zone border; site
number on Fig. 2.10)
Activity fraction transported across the
border from the fire area, %.
Doses at the border
of the zone, µSv.
137Cs
90Sr
239+240
Pu
Forest fire near Vesniane (1 km; 1)
0.32
0.40
0.004
1.4
Forest fire near Krasne (5 km; 2)
0.26
0.33
0.004
0.3
Forest fire near Buryakivka (14 km;
3)
0.15
0.20
0.002
1.6
Forest fire near Chistogalivka
(20 km; 4)
0.11
0.13
0.002
1.1
Forest fire near Kopachi (11 km; 5)
0.20
0.25
0.003
1.8
Forest fire near Leliv (24 km; 6)
0.06
0.08
0.001
0.3
At the present time during forest and field fires the effective dose from the external exposure
will be higher than the expected doses from the internal exposure for the participants of firefighting
in the ChEZ territory even in the fuel traces of radioactive fallout at the highest levels of
contamination with 90Sr, 238241Pu and 241Am in proportion to the 137Cs contamination. In a forest
fire more than half of the expected effective dose of the internal exposure may be caused by the
inhalation of 90Sr. At field fires one third of the value of the expected effective dose of internal
radiation exposure of the firefighters can be caused by the inhalation of 90Sr, 238241Pu and 241Am
with the approximately equal contribution of these radionuclides. The influence of the beta-emitting
241Pu on the expected internal effective dose for the personnel is similar to this one of the alpha-
emitting radionuclides 238-240Pu and must be taken into account (Kashparov, et al., 2015b).
According to analyses of remote sensing data the area of large grass fires, ground and crown
forest fires in the Chernobyl Exclusion Zone in April 2015 was 10 127 ha in total: 1735 ha burned
on April 27, 5761 ha on April 28, and 2631 ha — on April 29. (Evangeliou, et al., 2015b). This
area is more than 30 times higher than the official data and is consistent with Greenpeace data
(Fires, 2015). Grass fire burned 6250 ha, while ground and crown forest fires burned 2737 ha and
1140 ha, respectively. The maximum terrestrial density of the radionuclide contamination inside the
perimeter of the forest surface fire in the areas number 306308 of Lubyanka forest ranger district
was 137Cs: 1040 kBq·m-2; 90Sr: 368 kBq·m-2; 238-240Pu: 11.4 kBq·m-2 and 241Am: 14.4 kBq·m-2
(Evangeliou, et al., 2015b). The expected effective doses for the firefighters were estimated on the
basis of data on the area and type of the largest wildfire since 1992 in the Chernobyl Exclusion
Zone on April 27–29, 2015 to levels of radionuclide contamination and fuel material. These doses
did not exceed 0.64 mSv for external and 0.37 mSv for internal exposure per work hour (Fig. 2.11;
Kashparov, et al., 2015b). On April 26–29, 2015 in a ten-hour working day the total expected
effective dose from Chernobyl radionuclides for firefighters is estimated at maximum 42 μSv,
which is lower than the reference levels of the individual doses for the ChEZ personnel of 3000 μSv
per year (RSSU-97, 1998).
The external dose of radiation for firefighters can be reduced by minimizing the time of
personnel staying in the area with high density of 137Cs contamination, shielding gamma radiation
by material of car cabins (down to a tenth), using remote-controlled tools (cars, tractors, etc.), and
by aviation used for forest freighting keeping a safe distance.
42
Fig. 2.11: Maps of the terrestrial contamination density of 137Cs in the ChEZ (a):
and expected effective radiation doses for the participants of firefighting for one hour of work near
the fire frontline in 26–29 April 2015 (Kashparov et al., 2015b):
Inhalation of radionuclides can be reduced by factors of tens and hundreds by the use of
respirators etc. In cases of meadow and forest fires, radioactive aerosols of micron and submicron
sizes are found in the air. The retention efficiency of these particles by Petrjanov cloth, used in
respirators, exceeds 98%. Therefore, in order to protect the respiratory tract during firefighting, it
seems expedient to apply various types of respirators and other individual protective tools for
respiratory organs, and also to use of sealed car cabins and, if it is necessary, shielded car cabins.
The contamination of skin and clothes of the firefighters due to radioactive aerosol
deposition is estimated as much lower than the permitted levels of surface contamination
(Kashparov, et al., 2015b).
<40 kBq/m2;
40-185 kBq/m2;
185-555 kBq/m2;
>555 kBq/m2
b – external dose
<0.1 µSv
0.1-0.3 µSv
0.3-0.64 µSv
c – internal dose
<0.01 µSv
0.01-0.1 µSv
0.1-0.37 µSv
43
Taking into account the sharp decrease of the airborne radionuclide concentration with the
distance from the source of release in case of forest fires, it can be stated that the inhalation
component of the total dose (as well as the external irradiation from radionuclides in air) does not
give a significant contribution to radiation exposure for people in the Exclusion Zone which are not
involved in firefighting and for the population outside of the Exclusion Zone (Yoschenko, et al.
2006a; Khomutinin, et al., 2007).
Besides of the radiological risk of fires for the participants of firefighting, personnel of the
ChEZ and population in the contaminated areas, providing information on fires in the Chernobyl
Exclusion Zone is socially and psychologically important for the population of both Ukraine and
other countries. In this connection, special attention should be focused on the firefighting capacity
in the ChEZ and also on the creation of modern systems of fire detection and firefighting
(Evangeliou, et al., 2014, 2015a,b).
2.4. Radiological situation outside the ChEZ
2.4.1. 137Cs
The milk, cattle meat and non-wood forest products (mushrooms, berries and bushmeat)
current exceed the permissible content of 137Cs.
In the settlements of the northern regions of Ukraine, where the average dose is more than
1 mSv·y-1, the main contribution to the total dose formation is provided by internal exposure due to
the consumption of milk and non-wood forest products (Fig. 2.8). At this point there are about 10
settlements (Fig. 2.8) where the specific activity of 137Cs in milk and cattle meat is always 3–4
times greater than PL-2006 standards. Also there are 50 settlements where the content of
radioactive cesium in milk may exceed the permissible levels (Likhtarev et al., 2012, 2013; UIAR,
2015; Ministry of Ukraine of Emergencies, 2011). The reason for such high levels of 137Cs in plants
and animal products is abnormally high bioavailability of the cesium on peat soils with a relatively
low contamination density of the soil with 137Cs (about 100 kBq·m-2) (Maloshtan et al., 2015).
Beside the waterlogged peats, abnormal high bioavailability of radioactive cesium that
slowly changes in time (Fig. 2.12) (Maloshtan et al., 2015; UIAR, 2015) is also known for arctic
and alpine ecosystems due to the low rate of decay of soil organic matter at high moisture content
and low temperature. As a result, such soils are characterized by high acidity of soil solution, high
concentration of ammonia and nutritional deficiency. High 137Cs transfer factors (TF) are also
caused by the species composition, low productivity and quality of the natural meadows, and by the
soil properties: high content of organic matter (> 70 %) in peat-bog soils formed at sands and low
contents of clay minerals, phosphorus, exchangeable potassium and calcium.
44
Fig. 2.12: The dynamics of the milk contamination by 137Cs which is produced in the private farms
of the most critical settlements during the grazing period (arithmetic mean, standard deviation,
n > 20) (Maloshtan et al., 2015; UIAR, 2015: Current radiation situation at the agricultural areas in
Ukraine)
2.4.1.1. Milk
The data of the last dosimetry certification of the settlements in 2012 for radiation protection
of population on the average specific activity of 137Cs in cattle milk (the arithmetic mean of five
samples) (Lihtarov, I.A., et al. 2013) and the results of the monitoring of the UIAR of the National
University of Life and Environmental Sciences of Ukraine indicate that most of the milk with 137Cs
content above the permissible hygiene state standards PL-2006 (100 Bq·l-1) and also most of the
beef with 137Cs content of over 200 Bq·kg-1 are produced in the private farms of Rivne and
Zhytomyr regions. The most critical villages, where the specific activity of 137Cs in cattle is several
times greater than the PL-2006 standards, are located only in Rokytne district of Rivne region.
The network of the monitoring investigations of the UIAR covers the most critical
settlements of Rokytne, Sarny and Dubrovytsia districts of Rivne region (Table 2.5). The
contamination density by 137Cs of the monitored territory varies from 20 to 100 kBq·m-2. The
samples of the whole milk were collected during the grazing period in the most critical settlements
of the region that were contributed to the third Zone of a Guaranteed Voluntary Resettlement.
The analysis of the obtained results revealed that the situation in these settlements of the
monitoring network (Rokytne district) has not changed significantly for the last five years, taking
into account the variability of the values due to different factors (Fig. 2.12, Table 2.5). In all
settlements of the monitoring network the 137Cs content in the collected milk samples was several
times higher than the permissible limits. During 2015 the highest average values of the 137Cs
content in milk were recorded in the Perehodychi village of Rokytne district (870 Bq·kg-1, in May).
The contamination of milk in a separate settlement depends on pastures where the cattle are
grazed because the contamination density of 137Cs of pastures can vary significantly even within the
area of this village. Besides it, the pastures are located on soils with the different agrochemical
properties and different mode of moisture and hence different transfer coefficients of 137Cs in
plants.
Milk, grazing season
0
200
400
600
800
1000
1200
2004 2006 2007 2008 2011 2012 2013 2014 2015
Year
А, B q k g
-1
Vezhitsa
Drozdyn'
Yelne
Stare Selo
PL-2006
45
The results of the monitoring confirm that in the near future the radiation situation will not
become significantly better, because the possibilities of the natural autorehabilitation (the fixing of
radioactive cesium in the soil) without the use of countermeasures are almost exhausted. In the
critical settlements where the measures to reduce the radioactive cesium intake in milk are not
applied the decrease of the contamination of milk products will occur only through the decay of this
radionuclide that is observed during the recent years (Fig. 2.12).
Table 2.5: The average values of the 137Cs content in samples of whole milk (Bq·kg-1)
produced in the private farms of the critical settlements of Rokytne district according to the results
of the monitoring during 2011–2015 (UIAR, 2015: Current radiation situation at the agricultural
areas in Ukraine) and the data of the certification in 2012 (Lihtarov, I.A., et al. 2013).
Settlement
Data of the the monitoring during 2011–2015, Bql-1
(Mean±SD n>20)
Data of the certification
in 2012, Bq
l
-1
2011
2012
2013
2014
2015
2012
Stare Selo
303±193
303±107
225±100
270±110
330±130
381
Drozdyn
434±215
453±169
186±41
270±120
323±135
186
Vezhytsya
482±128
560±183
258±94
440±120
418±160
288
Perehodychi
346±197
285±187
137±22
240±100
470±230
179
Berezovo
124±43
104±75
80±40
80±40
538
Yelne
193±147
185±99
350±200
134±111
18±5
364
2.4.1.2. Wild mushrooms and berries
Among all components of the forest ecosystems the largest accumulation of the radioactive
cesium from the soil is in mushrooms and berries (blueberries, cranberries, blackberries, etc.). In the
case of the organized procurement for export or sales in markets the radionuclide content in
mushrooms and berries is always controlled. But most of mushrooms and berries consumed by the
population are not controlled at all.
The transfer of cesium in wild mushrooms varies significantly between mushroom species
and depends on growing conditions (forest type) within each of them. In later years mushroom
sampling focused on the areas with highest 137Cs deposition in Ukraine. Mushroom species sampled
include commonly consumed mushrooms. Currently, 137Cs concentrations in Ukrainian mushrooms
(outside the Chernobyl Exclusion Zone) vary from <10 Bqkg-1 (fresh weight) up to >10 kBqkg-1
according to species and sampling sites. The maximum contamination level of dried mushrooms
can reach hundreds of kBqkg-1 (Ministry of Ukraine of Emergencies, 2011).
About 50% of all samples of mushrooms (n = 77) that were collected in different regions of
Ukraine during the monitoring in the UIAR in 2013–2014 did not comply with the requirements of
the PL-2006. Today, the probability of exceeding the permissible content of 137Cs (500 Bq·kg-1) in
types of mushrooms that are characterized by a strong accumulation of radionuclides is quite high
throughout the Ukrainian Polissia territory (at the contamination density of more than 20 kBq·m-2)
(IAEA, 2006).
In Ukraine blueberries are the most widespread wild berries which are stored by the
population for both personal consumption and sale. In contrast to mushrooms the parameters of the
137Cs contamination of blueberries are much better. According to the monitoring results of the
contamination of these berries in 2013–2014 samples with the exceeding of the permissible level
(500 Bq·kg-1) were not found. The 137Cs content in the collected samples varied within a range of
45 to 210 Bq·kg-1 (UIAR, 2015: Current radiation situation at the agricultural areas in Ukraine).
46
2.4.2. 90Sr
2.4.2.1. Cereal
The 137Cs content in grain products which are now produced in Ukraine usually is not bigger
than a few Bq·kg-1 and less than the established permissible level of 50 Bq·kg-1. The level of the
contamination of these agricultural products with another long-lived radionuclide originating from
Chernobyl, 90Sr, differs in some regions. Thirty years after the Chernobyl accident, the Ivankov
district of Kyiv region adjacent to the Exclusion Zone (Fig. 2.9) produces grain in which in some
cases the 90Sr content reaches 60 Bq·kg-1, exceeding the established in Ukraine permissible levels
for food grains (20 Bq·kg-1) (Kashparov, et al, 2013; Otreshko, et al, 2014). The soil contamination
density of this critical area with the 90Sr varies within the range of 5–40 kBq·m-2. The monitoring of
these products' contamination which was conducted in the UIAR of the NUBiP of Ukraine in 2009–
14 revealed that in spite of the long period of time that had passed after the contamination, in
general the situation of the grain contamination with 90Sr in this region has not improved, and in
some cases it has become worse. During the last three years in some areas the radioactive strontium
content in grain samples was significantly higher than the values that were recorded more than ten
years ago. In other words the bioavailability of 90Sr has increased in these areas (Fig. 2.13). There
are two reasons for this fact. Firstly, the 90Sr was in the matrix of the particles of the exposed
nuclear fuel in the content of the emergency fallout and was not available to plants. Over time, these
particles were dissolved and transferred into the soil solution and this radionuclide was introduced
into the migration processes (the bioavailability was increased). Secondly, in these areas
agrotechnical measures are not carried out properly (unbalanced fertilization, absence of the liming
of acid soils). Liming of the soil decreases 90Sr content in plants by half.
The dynamics of the contamination of vegetation (grain and wood) with 90Sr is mainly
determined by the kinetics of fuel particle dissolution and by changes in the mobile radiostrontium
content in the root-layer (Fig. 2.13). Depending on the fuel particle dissolution rate, root
contamination of plants with 90Sr is very important for radiating protection of the human and
environment after the Chernobyl accident (Kashparov, et al, 2013; Otreshko, et al, 2014).
Fig. 2.13: Dynamic of the 90Sr average CR (transfer factor) in grain and theoretical
dependence (solid line) for the Zone in Ivankov district of Kyiv region (Kashparov, et al, 2013;
Otreshko, et al, 2014).
According to the results of the research the 137Cs content in most samples was greater than
10 Bq·kg-1 (the standard value was 50 Bq·kg-1), while the specific activity of 90Sr in grain varied
47
within a range of 5 to 60 Bq·kg-1 (standard value was 20 Bq·kg-1). Overall, more than 50% of the
collected samples of grain did not comply with the established permissible levels of radionuclide
content (PL-2006, 2006). The area of these critical agricultural lands is less than 2000 hectares and
the gross grain yield is less than 2000 tons.
2.4.2.2. Firewood
Due to price increases of gas and other energy sources, wood is used by the population and
local administrations of Ukraine, including Chernobyl, more and more often. On 30 October 2015
the European Union sent a test furnace incinerator to Chernobyl for the burning of radioactive wood
and for water heating for the town of Chernobyl in the ChEZ (SAUEZb, 2015). A thermal power
plant where about 600 tons of wood a day can be burned has been built near the Ivankov village
(Ukrainian, 2014).
According to the hygiene standards the permissible levels of the 90Sr and 137Cs content in
firewood are 60 Bq·kg-1 and 600 Bq·kg-1, respectively.
The 90Sr and 137Сs content in soil and wood was measured along the southern fuel trace of
the Chernobyl fallout, in the Ivankov district of Kyiv region in 2012–2013 (Otreshko, et al., 2015).
The transfer factor of 90Sr to wood of deciduous trees and pine rose to 34±20 and
61±56 (Bq·kg-1)/(kBq·m-2), on average, that exceeds the values recommended by IAEA by more
than a factor of ten (IAEA, 2010). Among 26 analyzed samples, the 90Sr-specific activity was lower
than the permissible level for firewood in only four, and in 20 samples it exceeded 100 Bq·kg-1.
Burning of this wood can result in the formation of ash with the specific activity corresponding to
the level of radioactive waste (10 kBq·kg-1).
There is a risk of the exceeding of the hygiene standard of the 90Sr content in firewood and
brushwood almost throughout the territory of Ivankov district, where the density contamination by
90Sr is higher than 5.5 kBq·m-2, (Fig. 2.9). This raises a concern for the population of the region.
48
3. Analysis of interplay of current levels of radioactive contamination
and Evacuation Policies in Ukraine, Belarus, Russia
As a result of the Chernobyl catastrophe basic Laws of Belarus, Russia and Ukraine «On
legal regime of territories affected …» and «On the status and social protection of citizens suffered
…» were adopted in the beginning of 1991 before the collapse of the USSR based on the uniform
Concept for habitation of population within the territories of higher levels of radioactive
contamination. The basic principle of the Concept is that the value of effective dose of additional
exposure connected with the Chernobyl catastrophe should not exceed 1.0 mSv per year and
70.0 mSv per all life for the critical group of population (children born in 1986) besides the doses of
natural background radiation received by the population during a pre-accident period in the same
conditions. Protective measures provided by these laws (resettlement, providing of free residence,
special health service, various privileges and compensations such as early retirement, free transport
and food, reduced coast of utility bills, etc.) had to be financed by the funds of the general union
budget of the USSR. After the collapse of the Soviet Union in the end of 1991, the liquidation of the
consequences of the Chernobyl accident had to be financed by the budgets of the independent
states. Due to the economic crisis of those years it was impossible to finance all of measures
provided by the law.
The function of the state with respect to the Chernobyl catastrophe is represented in the
Constitution of Ukraine: «… overcoming of the consequences of the Chernobyl catastrophe a
catastrophe of global scale and preservation of the gene pool of the Ukrainian people, is the duty
of the State» (Article 16). In 1992–98 a special Fund for measures for mitigating Chernobyl
accident consequences and for social protection of population was created as part of the Ukrainian
Budget. This Chernobyl Fund received fees from enterprises and economic organizations
irrespective of subordination and proprietary forms in amount of 10–19% of payroll allocating
transferred sums to the costs of works and services. From January 1, 1999, fee allocation to the
Fund for Measures on Mitigating Chernobyl Accident Consequences and Social Protection of
Population was stopped. The Decree established that financing of the expenditures from the Fund
for Measures on Mitigating Chernobyl Accident Consequences and Social Protection of Population
is carried out at the expense of State Budget of Ukraine. Notwithstanding the fact that during the
years of independence Ukraine spent more than US$10bn on the liquidation of the Chernobyl
catastrophe consequences, in price equivalent the laws were not financed by more than 57%
(Ministry of Ukraine of Emergencies, 2011).
In Belarus US$19.4bn were spent for the financing of programs providing for the liquidation
of the consequences of the accident during the period 1991–2010. In 2011–15 the sum of
US$1 726.6bn was divided by the following way: 43.4% were given out for social protection and
medical care of the population; 41.9% for the social development of the affected regions; 13.6% for
the radiation protection and the targetted application of countermeasures; 1.1% for the scientific and
information support (Chernikov, 2014). In recent years the state policy of Belarus was aimed at the
redistribution of funds in individual payments to mitigate the potential risk for population health, at
the financing of the state programs for social and economic recovery of the regions, and at the
addressed health service of citizens.
During the post-accident period the radiation situation in the area radioactively contaminated
as the result of the Chernobyl NPP accident was improved significantly because of the radioactive
decay of radionuclides, application of countermeasures and autorehabilitation processes. In Belarus
the number of settlements officially designated to the different zones of the radioactive
contamination (the status is reconsidered by the Government of Belarus every 5 years) decreased by
a factor of 1.5 and the number of people who live there decreased by a factor of 1.9 (Fig. 3.1). The
application of the countermeasures made it possible to reduce the number of settlements which
registered milk contaminated with 137Cs and 90Sr above the permissible levels in private farms by
several orders of magnitude (Chernikov, V., 2014.). Also the last made it possible to reduce levels
of radionuclide content in products in general.
49
Fig.3.1: Dynamics of the number of settlements and population in the contaminated areas of
Belarus (Tsybulko, 2015)
In Russia from 1991 (Government Decree No. 237-p from 28 December 1991) until 2005
the number of settlements in the zones of the radioactive contamination decreased from 7012 to
4413 (Government Decree No. 197 from 7 April 2005). By 2056 a significant reduction of the
number of settlements in the areas of the radioactive contamination to 984 is predicted. More than
95% of these settlements will be in the Zone of residence with privileged socioeconomic status
(Sanzharova, 2015). The number of settlements situated within the zones of the radioactive
contamination was reduced to 3864 settlements according to the Resolution of the Government of
the Russian Federation on October 8, 2015 No 1074 “On approval of the list of settlements situated
within the zones of the radioactive contamination after the Chernobyl accident” (Cabinet of
Ministers of Russia, 2015). At the end of 2015 small villages where now nobody lives and also a
part of the settlements of Zone with Preferential Socioeconomic Status with low doses for the
population have been excluded from this list (Bruk, et al., 2015).
In Ukraine, since 1991 the status of 2293 settlements designated to the different zones of the
radioactive contamination has not been reconsidered. Reasons for this include the difficulty of the
boundary-changing procedure of the contaminated zone by the Parliament of Ukraine, which was
legally approved in 1996, and the negative attitude of the local government and population to these
changes for fear of losing privileges and compensations. Only once in 2004, 6 settlements, where
the population was not really resettled, were reattributed from the second Zone of an Unconditional
(Obligatory) Resettlement to the third zone by the Decree of the President of Ukraine in order to
legalize the state financing of the countermeasure applying in these settlements (Verkhovna Rada
of Ukraine. Resolution, 2004). The population was resettled not from all of the settlements of the
second Zone of an Unconditional (Obligatory) Resettlement. Nowadays, the process of the
resettlement has been stopped and 532 families of the Zhytomyr region are still living in the second
zone. On 28 December 2014 the biggest, fourth Zone of an Enhanced Radioecological Monitoring
(1290 settlements), where the most of the affected population live (more than 1.5 million of people)
was eliminated as result of the changes in the Laws of Ukraine «On the legal regime of the
territories exposed …» and «On the status and social protection of citizens suffered …» (Verkhovna
Rada of Ukraine. On Amendments, 2015). To this day there is no decree of the Government of
Ukraine for the changes in the list of settlements designated to the zones of the radioactive
contamination. The fourth Zone does not exist anymore, but there are 1290 settlements still
classified as Zone 4.
The main items of expenditure of the state budget of Ukraine for the liquidation of the
consequences of the Chernobyl accident are the compensation and privileges providing to the
50
population for the potential hazard for health, and also the expenses for the ChEZ and ChNPP. In
Ukraine as a result of lack of financing of the measures provided for the social protection of the
affected population, the legislative social rights and guarantees of the population suffered from the
Chernobyl accident are not fully supported.
In 2015 the average annual effective dose of the population exposure in Belarus was equal
or higher than 1 mSvy-1 in 82 settlements which amounted 3.5% of the total number of settlements
(2396) located in the areas of radioactive contamination. In 9 settlements the dose was higher than
2 mSvy-1 but less than 5 mSvy-1 (The Catalog, 2015).
In Russia from 4413 settlements designated to the zones of radioactive contamination in 276
settlements the average annual effective dose for the critical group of the population (AAED90, the
ninth decile of the distribution excluding active countermeasures) was greater than or equal to
1 mSv, and in 8 settlements it was higher than 5 mSvy-1 (Bruk, et al. 2015).The maximum AAED90
was for the population of Zaborye village in the Bryansk region. At the contamination density of the
territory of 137Cs of about 2200 kBqm-2 in 2014 in this settlement the AAED90 from external and
internal exposure was 3 and 5 mSv, respectively. In Bryansk region 978 settlements have been
assigned in 2005 to the zones of radioactive contamination: 4 Exclusion Zone, 202 Zone of
Evacuation; 237 Living Zone with the Right to Resettle and 535 Zone with Preferential
Socioeconomic Status (Government Decree No. 197 from 7 April 2005). Now after October 2015 in
Bryansk region 749 settlements designated to the zones of radioactive contamination: 4
Exclusion Zone, 26 Zone of Evacuation; 191 Living Zone with the Right to Resettle and 528
— Zone with Preferential Socioeconomic Status (Cabinet of Ministers of Russia, 2015).
In Russia the relatively large doses of the radiation exposure of population are caused by the
fact that after the Chernobyl accident the evacuation of population was carried out in the territory at
a 137Cs contamination density of above 1480 kBqm-2 (40 Cikm-2), while in Belarus and Ukraine
the threshold was 555 kBqm-2 (15 Cikm-2). At the present time in Russia in Krasnogorsk districts
of Bryansk region the population continues to reside on the territories with contamination densities
above 1480 kBqm-2 (40 Cikm-2): Barsuki 2165 kBqm-2, Zaborje 2198 kBqm-2, Kovali -
1706 kBqm-2, Tugani 1576 kBqm-2, Nikolaevka — 1650 kBqm-2, Novoaleksandrovka — 1502
kBqm-2, etc.) (Bruk, et al., 2015).
In Ukraine from 2293 settlements assigned to the zones of radioactive contamination in
2012 (the last dosimetry certification was carried out) only in 26 settlements the average annual
effective dose for the population was equal or higher than 1 mSvy-1. In 6 settlements the dose was
higher than 2 mSvy-1 but less than 5 mSvy-1 (Lihtarov, et al. 2013). The main contribution to the
dose is made by the internal radiation as result of the consumption of local foods (milk, meat,
mushrooms and berries) with a high content of radionuclides.
In Ukraine, Belarus, and Russia, different officially approved methods of assessment of the
effective doses for the population with different degrees of conservatism are used for the
management decisions. As a rule, the calculated effective doses for population are 210 times
higher than the real ones (Bruk, et al., 2015; Lihtarov, et al., 2013). It makes the data on the
radiation doses of the population in different countries after the Chernobyl accident difficult to
compare (Table 4.1).
Nowadays, 30 years after the Chernobyl accident the resettlement of the population from the
contaminated area would be unjustified and not considered in Ukraine.
In Ukraine, Belarus and Russia the average annual effective dose of 1 mSv is accepted as the
dose limit. At the exceeding of this limit protective measures (countermeasures) are considered
justified. In Belarus protective measures in agriculture are applied when the expected effective dose
for the population is higher than 0.1 mSvy-1.
In the new version of the International Basic Safety Standards (IAEA, 2011) and the
European legislation developed on the base of them the definite dose limits are not used for the
decision making in the case of a radiation accident (evacuation, resettlement, etc.) and a situation of
existing radiation exposure (limiting of the food and water consumption, countermeasures applying,
etc.). The reference levels of radiation for the representative person of any values (but the values
51
should be as low as possible) must be established by the leadership of the country depending on the
concrete situation and taking into account economic and social factors. For the evacuation and
resettlement the IAEA recommends to use the reference level in the range of 20 to 100 mSv and for
the applying of the protective measures in the situation of the existing radiation exposure this one
may vary within the range of 1 to 20 mSvy-1 (IAEA, 2011).
Since in Ukraine the main contribution to the dose value is provided by the internal radiation
exposure, at the present time the use of protective measures in agriculture (radical improvement of
grassland and application of ferrocyn to cows) allows people to obtain products with radionuclide
content below the permissible level, and to decrease the average annual effective dose for the
population to the level below 1 mSv in all settlements of Ukraine (Jacob, et al., 2009).
Unfortunately, countermeasures for the radiation protection of the population have not been applied
in Ukraine since 2009, due to lack of funds in the state budget of Ukraine for the financing of all
programs for the liquidation of the consequences of the Chernobyl accident. Besides this, social
payments for the populations (compensations and privileges) are considered more important than
the expansion of the radiation protection.
In Russia for a long time in a number of settlements it has been impossible to decrease the
average annual effective dose below 1 mSv, because of the big contribution to the total dose is
provided by the external radiation exposure under the high contamination densities of the territory
with 137Cs and the low decontamination efficiency of the area (the radiological effectiveness is not
bigger than a factor of 1.5) (Jacob, et al. 2009).
At the present time the radiological and ecological situation outside the ChEZ changes very
slowly and will be dangerous for the population for several decades. Mainly it is connected with a
radioactive decay of 137Cs which half-life is about 30 years. High levels of the contamination of the
Exclusion Zone by the long-lived 239,240Pu and the presence of nuclear dangerous objects make the
returning and inhabitation of the population on these areas impossible for tens or hundreds of
thousands of years.
Table 4.1: The amount of settlements in Ukraine, Belarus, Russia where the effective doses are
greater than the established dose limits (The Catalog, 2015; Bruk, et al. 2015; Likhtarev, et al.,
2013)
Country
Year
Number of settlements
Total in zone
1–5 mSvy-1
>5 mSvy-1
Belarus
2015
2396
82
0
Russia
2014
4413
276
8
Ukraine
2012
2293
26
0
52
Conclusion
In spite of the improvement of the radiation situation 30 years after the Chernobyl accident a
whole complex of problems connected with the protection of the population and rehabilitation of
the lands still needs to be solved in the contaminated areas of Belarus, Russia and Ukraine. The
most important of these problems are presented below:
About 9000 settlements in Belarus (2396), Russia (4413) and Ukraine (2293) where
over 4.5 million people live are assigned to the zones of the radioactive contamination (IAEA,
2006). The average annual effective doses for the population exceed 1 mSv in more than
400 settlements.
More than 10000 km2 are unusable for economic activity.
For an indefinite period there will be an Exclusion Zone around the ChNPP in
Ukraine and Polesie State Radioecological Reserve in Belarus.
In the part of the radioactively contaminated area it is impossible to provide the
production of agricultural products which comply with radiation and hygiene standards;
Wood and other forest products will be radioactively contaminated for a long time.
Different radiobiological effects of non-human organisms are revealed in the ChEZ.
Among the post-Chernobyl problems the rehabilitation of the settlements is the most
difficult and important. Because in order to solve this problem it is need to solve not only
radiological but also economic, demographic and socio-psychological problems step by step.
For example, nowadays only in Ukraine more than 10000 residents receive the internal dose
of more than 1 mSv every year through the consumption of the radioactively contaminated milk in
25 settlements (Likhtarev, et al., 2012, 2013). The collective dose per year for these residents (more
than 10 man-Sv) is much higher than the collective dose for all staff of the ChEZ. Also this
collective dose will be more significant than the consequences of any hypothetical emergency
situations which can occur in the ChEZ such as forest fires (Khomutinin, et al., 2007, Ministry of
Ukraine of Emergencies, 2011). However, in recent years the protective measures aimed at the
reducing of the radioactive contamination of products and the decrease of the doses for the
population are not carried out according to the Law of Ukraine (Verkhovna Rada of Ukraine. On
the Legal, 1991).
Thus, at the present time the measures aimed at the radiation protection of the
population in the areas affected by the Chernobyl accident are the most important of the
Chernobyl tasks.
53
References
1. Abahyan, A.A., et al.1986. Information about the accident at the Chernobyl Nuclear Power
Plant and its consequences prepared for the IAEA. Atomic Energy 61(5): 301–320. (In
Russian)
2. Aliyu A.S., Evangeliou N., Mousseau T.A., Wu J.,Ramli A.T. 2015. An overview of current
knowledge concerning the health and environmental consequences of the Fukushima Daiichi
Nuclear Power Plant (FDNPP) accident. Environment International 85: 213–228.
3. Andriesse, C.D. & Tanke, R.H. 1984. Dominant factor in the release of fission products
from overheated urania. Nuclear Technology 65: 415–421.
4. Bondar O.I. et al. 2013. REPORT "The development of materials for the project of the
Chernobyl Biosphere Reserve", State Environmental Academy of Postgraduate Education
and Management, Kiev, Ukraine. (in Ukrainian).
5. Bruk, G.Ja., et al. 2015. The average annual effective doses for the population in the
settlements of the russian federation attributed to zones of radioactive contamination due to
the chernobyl accident (for zonation purposes), 2014. Radiation Hygiene 8(2): 32–128.
http://www.radhyg.ru/index.php/jour/article/view/6/8
6. Bugai D., Skalskyy A., Dzhepo S., et al. 2012. Radionuclide migration at experimental
polygon at Red Forest waste site in Chernobyl zone. Part 2: Hydrogeological
characterization and groundwater transport modelling . Applied Geochemistry 27(7): 1359–
1374
7. Cabinet of Ministers of Russia. Resolution of Cabinet of Ministers of Russia number 1074
on 8 October 2015 «On approval of the list of settlements situated within the zones of the
radioactive contamination after the Chernobyl accident» (in Russian).
8. CD, ATLAS, Ukraine, radioactive contamination, MES, “Intelligence Systems GEO”, Ltd.,
2008.
9. Chernikov V. 2014. Head of Department in the aftermath of the Chernobyl disaster Ministry
of Emergency Situations of the Republic of Belarus. Pers. comm.
10. Chernobyl Nuclear Power Plant and RBMK reactors. 1996. Bulletin of Ecological
Conditions of the Exclusion Zone 3: 4–8. (in Ukrainian, French)
11. De Cort, M., et al. 1998. Atlas of Caesium Deposition on Europe after the Chernobyl
Accident, Rep. 16733, Office for Official Publications of the European Communities,
Luxembourg. ISBN 92–828–3140-X.
12. EC, 1986. EUROPEAN COMMISSION, Council Regulation (EEC) No. 1707/86 OJ No. L
146 of 31 May 1986: 88–90.
13. Evangeliou N., Zibtsev S., Myroniuk V. et al. Resuspension of radionuclides due to
wildfires near the Chernobyl Nuclear Power Plant (CNPP) in 2015: An impact assessment.
(in press)//. 2015b.
14. Evangeliou, N., Balkanski, Y., Cozic, A. et al. 2014. Wildfires in Chernobyl- contaminated
forests and risks to the population and the environment: A new nuclear disaster about to
happen? Environment International 73: 346–358.
15. Evangeliou, N., Balkanski, Y., Cozic, A. et al. 2015a. Fire evolution in the radioactive
forests of Ukraine and Belarus: future risks for the population and the environment.
Ecological Monographs 85(1): 49–72
16. Geraskin S.A., Zimina L.M., Dikarev V.G. et al. 2003. Bioindication of the anthropogenic
effects on micropopulations of Pinus sylvestris, L. in the vicinity of a plant for the storage
and processing of radioactive waste and in the Chernobyl NPP zone. Journal of
Environmental Radioactivity 66: 171–180,
17. Hilpert, K. & Nurberg, H.W. 1983. Mass spectrometric study of the potential of Al2O3/SiO2
additives for the retention of caesium in coated particles. Nuclear technology 63: 71–76.
18. IAEA, 1991. International Chernobyl Project: Technical Report. International Advisory
Committee. Vienna.
19. IAEA, 1992. International Chernobyl project, technical report. ISBN 92–0-400192–5.
54
20. IAEA, 1994. Guidelines for agricultural countermeasures following an accidental release of
radionuclides. A joint undertaking by the IAEA and FAO. TRS No.363. ISBN 92–0-
100894–5.
21. IAEA, 1996a. One decade after Chernobyl: effect on the environment and further
prospectives. IAEA/J1-CN-63, Vienna, Austria.
22. IAEA, 1996b, International Basic Safety Standards for Protection Against Ionizing
Radiation and for the Safety of Radiation Sources. 1996. International Atomic Energy
Agency. Safety series No. 115, Vienna, 333p. ISSN 0074–1892; STI/PUB/996, ISBN 92–0-
104295–7
23. IAEA, 2006. Environmental consequences of the Chernobyl accident and their remediation:
twenty years of experience. Report of the Chernobyl Forum Expert Group “Environment”
(eds. L. Anspaugh and M. Balonov). Radiological assessment reports series, IAEA,
STI/PUB/1239, 166 pp.
24. IAEA, 2010. Handbook of parameter values for the prediction of radionuclide transfer in
terrestrial and fresh-water environments. Vienna: IAEA-TRS-472, 194p
25. IAEA, 2011. Radiation Protection and Safety of Radiation Sources: International Basic
Safety Standards. Interim Edition. General Safety Requirements. 2011. International Atomic
Energy Agency. Safety standards series No. GSR Part 3 (Interim), Vienna, 303 pp.
ISSN 1020–525X; STI/PUB/1531, ISBN 978–92–0–120910–8.
26. ICRP 103, 2007. 2007 Recommendations of the International Commission on Radiological
Protection (Users Edition). ICRP Publication 103 (Users Edition). Ann. ICRP 37 (2–4).
27. Ill`in, A.L., Avetisov, G.M. 1983. Criteria of Decisions to Be Taken on Measures for People
Protection in Case of a Reactor Accident. Medical Radiology 5: 92. (in Russian).
28. Ivanenko, I. 2015. Director of Department of Protected Areas of the Ministry of Ecology
and Natural Resources of Ukraine. Presentation “Chernobyl Radiation and Environmental
Biosphere Reserve - the stages of transformation”. http://dazv.gov.ua/ofitsijni-
dokumenti/derzhavni-zakupivli/808-materiali-kruglogo-stolu-yakij-vidbuvsya-13-listopada-
2015-r (in Ukrainian)
29. Izrael, Yu.A., Petrov, V.N., Severs, D.A.1987. Modeling of the radioactive fallout in the
neighboring to the accident on Chernobyl NPP zone. Meteorology and Hydrology 7: 5–12.
(In Russian).
30. Izrael, Yu.A., Vakulovsky, S.M., Vetrov, V.A., Petrov, V.N., Rovinsky, F.Ya., Stukin, E.D.
1990. Chernobyl: Radioactive Contamination of the Environment. Gidrometeoizdat
publishers, Leningrad, 223 pp. (in Russian)
31. Jacob, P., et al. 2009. Rural areas affected by the Chernobyl accident: Radiation exposure
and remediation strategies. Science of The Total Environment 408(1): 14–25.
32. Jost, D.T., Gaggeler, H.W., Baltensperger, U., Zinder, B., Haller, P. 1986. Chernobyl fallout
in size-fractionated aerosol. Nature 324: 22–23.
33. Kashparov, V., Levchuk, S., Protsak, V. et al. 2014. Mapping the contamination of Ivankiv
district territory with radionuclides. UIAR final report within the frameworks of contract
No.2013–04 from 19/11/2013, Kiev, UIAR, 47 pp.
34. Kashparov, V., Yoschenko, V., Levchuk, S., Bugai, D., Van Meir, N., Simonucci, C.,
Martin-Garin, A. 2012. Radionuclide migration in the experimental polygon of the Red
Forest waste site in the Chernobyl zone Part 1: Characterization of the waste trench, fuel
particle transformation processes in soils, biogenic fluxes and effects on biota. Applied
Geochemistry 27(7): 1348–1358.
35. Kashparov, V.A. 1987. Director of Ukrainian Institute of Agricultural Radiology, National
University of Life and Environmental Sciences of Ukraine. Pers. comm.
36. Kashparov, V.A. 2015. Director of Ukrainian Institute of Agricultural Radiology, National
University of Life and Environmental Sciences of Ukraine. Pers. comm.
37. Kashparov, V.A., Ivanov, Yu.A., Zvarich, S.I. Protsak, V.P., Khomutinin, Yu.V., Kurepin,
A.D., Pazukhin, E.M. 1996. Formation of Hot Particles During the Chernobyl Nuclear
Power Plant Accident. Nuclear Technology 114: 246–253.
55
38. Kashparov, V.A., Levtchuk, S.E., Otreshko, L.M., Maloshtan, I.M. 2013. Contamination of
agricultural products by 90Sr in Ukraine in the remote period after the Chernobyl accident.
Radiatsionnaya biologiya. Radioekologiya 53(6): 639–650. (in Russian)
39. Kashparov, V.A., Lundin, S.M, Kadygrib, A.M., Protsak, V.P., Levtchuk, S.E., Yoschenko,
V.I., Kashpur, V.A., Talerko, N.M. 2000. Forest fires in the territory contaminated as a
result of the Chernobyl accident: radioactive aerosol resuspension and exposure of fire-
fighters. Journal of Environmental Radioiactivity 51: 281–298.
40. Kashparov, V.A., Lundin, S.M., Khomutinin, Yu.V., Kaminsky, S.P., Levtchuk, S.E.,
Protsak, V.P., Kadygrib, A.M., Zvarich, S.I., Yoschenko, V.I., Tschiersch, J. 2001. Soil
contamination with 90Sr in the near zone of the Chernobyl accident. Journal of Environment
Radioactivity 56: 285–298.
41. Kashparov, V.A., Lundin, S.M., Zvarich, S.I., Yoschenko ,V.I., Levtchuk, S.E.,
Khomutinin, Yu.V., Maloshtan, I.N., Protsak, V.P. 2003. Territory contamination with the
radionuclides representing the fuel component of Chernobyl fallout. The Science of The
Total Environment 317: 105–119.
42. Kashparov, V.A., Protsak, V.P., Khomutinin, Yu.V. 2015a. Report of UIAR of NUBiP of
Ukraine “Radio-ecological study of the functional zone division of the exclusion zone to
improve the efficiency of the activity of the removal of Chornobyl NPP and transformation
the object of “Shelter” into an ecologically safe system”. No 1–137–14, State code 015–97,
code 1.2.10, 71pp. (in Ukrainian).
43. Kashparov, V.A., Zhurba, M.A., Kireev, S.I., Zibtsev, S.V., Myroniuk, V.V. 2015.
Estimates of expected doses of fire brigades in the Chernobyl exclusion zone in April 2015.
2015. Nuclear Physics and Atomic Energy, 16(4): 399 – 407.
44. Kashparov, V.O., Polischuk, S.V., Otreshko, L.M. 2011. Radiological problems of
agricultural production on the contaminated as the result of the Chernobyl accident area in
Ukraine. Chernobyl Research Bulletin, Bulletin of Ecological State of the Exclusion Zone
and Zone of an Unconditional (Obligatory) Resettlement 2(38): 13–30. (in Ukrainian)
45. Kauppinen, E.I., Hillamo, R.E., Aaltonen, S.H., Sinkko, K.T.S. 1986. Radioactivity size
distributions of ambient aerosols in Helsinki, Finland, during May 1986 after the Chernobyl
accident: preliminary report. Environmental Science and Technology 20: 1257–1259.
46. Khomutinin, Yu.V. 2014. Evaluation of radioecological safety of fresh water reservoirs in
Ukraine during late phase of ChNPP accident. Nuclear Physics and Atomic Energy 15(4):
389- 401.
47. Khomutinin, Yu.V., Kashparov, V.A., Kuzmenko, A.V. Pavlyuchenko, V.V. 2013. Forecast
of the dynamics and the risk of the exceeding the permissible content of 137Cs and 90Sr in
fish in the Kiev reservoir fish during the late phase of the Chernobyl accident.
Radiatsionnaya biologiya. Radioekologiya 53(4): 411–427. (in Russian)
48. Khomutinin, Yu.V., Kashparov, V.A., Kuzmenko, A.V. 2011. Dependence of the
accumulation coefficients of 137Cs and 90Sr by fish on potassium and calcium content in
water of limnetic pond. Radiatsionnaya biologiya. Radioekologiya 51(3): 374–384. (in
Russian)
49. Khomutinin, Yu.V., Yoschenko, V.I., Kashparov, V.O., Levchuk, S.E., Glukhovskiy, O.S.,
Protsak, V.P., Lundin, S.M. 2007. Assessment of radiological danger of hypothetical
forestfire in the Chernobyl exclusion zone. Chernobyl Research Bulletin, Bulletin of
Ecological State of the Exclusion Zone and Zone of an Unconditional (Obligatory)
Resettlement 1(29): 28–33. (in Ukrainian)
50. Kolb, W. 1986. Radionuclide concentration in ground level air from 1984 to mid 1986 in
North Germany and North Norway; influence of the Chernobyl accident. Physikalisch-
Technische Bundesanstalt PTB-Ra-18: 53–56.
51. Krivokhatsky, A.S., Dubasov, Y.V., Smirnova, E.A., Skovorodkin, N.V., Savonenkov,
V.G., Alexandrov, B.M., Lebedev, E.L. 1991. Actinides in the near release from the
Chernobyl NPP accident. Journal of Radioanalytical Nuclear Chemistry Articles 147: 141–
151.
56
52. Kuriny, V.D., Ivanov, Yu.A., Kashparov, V.A., Loschilov, N.A., Protsak, V.P., Yudin, E.B.,
Zhurba, M.A., Parshakov, A.E. 1993. Particle associated Chernobyl fall-out in the local and
intermediate zones. Annals of Nuclear Energy 20: 415–420.
53. Legislation of Russia. Federal Law "On Social Protection of Citizens Exposed to Radiation
as a Result of the Chernobyl Accident", 15 May 1991.
http://pravo.gov.ru/proxy/ips/?docbody=&nd=102011440&rdk=&backlink=1 (in Russian)
54. Levchuk, S., Kashparov, V., Maloshtan, I., Yoschenko, V., Van Meir N. 2012. Migration of
transuranic elements in groundwater from the near-surface radioactive waste site. Applied
Geochemistry 27(7): 1339–1347.
55. Levonevsky. On Legal Regime of Territories Affected to Radioactive Contamination as a
Result of the Chernobyl Accident, Act of Republic of Belarus, on 12 November, 1991 No
1227-XII. http://pravo.levonevsky.org/bazaby/zakon/text56/index.htm (in Russian).
56. Lihtarov, I.A., et al. 2012. General dosimetry certification and monitoring results of human
radiation counters in the settlements contaminated after the Chernobyl accident. Data on
2011. 14 Collection. Kyiv, 99 p. (in Ukrainian).
57. Lihtarov, I.A., et al. 2013. General dosimetry certification and monitoring results of human
radiation counters in the settlements contaminated after the Chernobyl accident. Data on
2012. 15 Collection. Kyiv, 33 pp. (in Ukrainian)
58. Maloshtan, I., Polischuk, S., Khomutinin, Yu., Kashparov, V. 2015. Dynamics of 137Cs
uptake to herbaceous plants at the peat-bog soils with abnormally high radiocesium
bioavailability. Nuclear Physics and Atomic Energy 16(3): 263 — 272
59. Mattsson, R., Hatakka, J. 1986. Hot particle in inhalate air after the Chernobyl accident.
Finnish Association for Aerosol research. Report Series in Aerosol Science 2: 28–30.
60. Mining Awareness. Fires around Chernobyl Revive Nuclear Nightmare, April 2015.
https://miningawareness.wordpress.com/2015/04/30/fires-around-chernobyl-revive-nuclear-
nightmare/
61. Ministry for Emergency Situations of the Republic of Belarus 1994. The concept of the keep
of Exclusion and Evacuation Zones. Approved by the Head of the State Chernobyl
Committee of Belarus, I.A. Kenik on 6/7/94, Minsk, 94 pp. (in Russian).
62. Ministry of Ukraine of Emergencies 2011. Twenty-five Years after Chornobyl Accident:
Safety for the Future. National Report of Ukraine, KIM, Kiev, 328 pp. ISBN 978–966–
1547–64–2.
63. Møller A. P. 1998. Developmental instability of plants and radiation from Cher- nobyl.
Oikos 81: 444–448.
64. Møller A. P., Mousseaue T.A. 2007. Species richness and abundance of forest birds in
relation to radiation at Chernobyl. Biol. Lett. 3, 483–486.
65. Møller A. P., Mousseaue T.A. 2009. Reduced abundance of insects and spiders linked to
radiation at Chernobyl 20 years after the accident. Biol. Lett. 5, 356–359.
66. Møller A. P., Mousseaue T.A. 2011. Efficiency of bio-indicators for low-level radiation
under field conditions. Ecological Indicators 11: 424–430.
67. Møller A. P., Mousseaue T.A., Milinevsky G., Peklo A., Pysanets E., Szép T. 2005.
Condition, reproduction and survival of barn swallows from Chernobyl. Journal of Animal
Ecology 74: 1102–1111
68. Møller A. P., Nishiumic I., Suzukid H.,, Uedab K., Mousseaue T.A. 2013. Differences in
effects of radiation on abundance of animals in Fukushima and Chernobyl. Ecological
Indicators 24: 75–81.
69. Mousseaue T.A., Møller A. P. 2014. Genetic and Ecological Studies of Animals in
Chernobyl and Fukushima. Journal of Heredity 105(5):704–709.
70. National Committee on Radiation Protection 1988. The Limit for the Individual Life Dose
Established for the Population of Controlled Areas of the RSFSR, the Ukrainian SSR and
Byelorussian SSR, Contaminated as the Result of the Chernobyl Accident, Concept.of
National Committee on Radiation Protection 22/11/1988. Approved by the Ministry of
Health of the USSR.
57
71. Otreshko, L.N., Levchuk, S.E., Yoschenko, L.V. 2014. Concentration of 90Sr in grain on
fuel traces of the Chernobyl radioactive fallout. Nuclear Physics and Atomic Energy 15(20):
171–177 (in Ukrainian)
72. Otreshko, L.N., Zhurba, M.A., Bilous, A.M., Yoschenko, L.V. 2015. 90Sr and 137Cs content
in wood along the southern fuel trace of Chernobyl radioactive fallout. Nuclear Physics and
Atomic Energy 16(2): 183–192.
73. PL-2006, 2006. State hygiene standards GN.6.1.1–130–2006. Permissible levels of 137Cs
and 90Sr in food and drinking water (PL-2006). 2006. Ofitsiinyi visnyk Ukrayiny 29: 142. (in
Ukrainian)
74. Radiation Safety Standards of Ukraine (RSSU-97). 1998. State Hygiene Norms, Kyiv. (in
Ukrainian).
75. Radiological state of the territories referred to the radioactively contaminated zones. 2008.
(ed. V.I. Kholosha). Veta, Kyiv, 54 pp. (in Ukrainian).
76. RSS-2000, 2000. Radiation Safety Standards of Belarus RSS-2000. State Hygiene Norms
2.6.1.8–127–2000, Minsk, Belarus (in Russian).
77. RSS-99/2009. Radiation Safety Standards RSS-99/2009. SanPin 2.6.1.2523–09. 2009.
Rospotrebnadzor, Moscow. (in Russian).
78. Salbu, B., Krekling, T., Oughton, D.H., Ostby, G., Kashparov, V.A., Brand, T.L., Day, J.P.
1994. Hot Particles in Accidental Releases From Chernobyl and Windscale Nuclear
Installations. Analyst 119: 125–130.
79. Sanzharova N. 2015. Deputy Director for Research of the All-Russian Scientific-Research
Institute Radiology and Agroecology. Pers. comm.
80. SAUEZ, 2015a. Official site of the State Agency of Ukraine for Exclusion Zone.
http://dazv.gov.ua/anonsi/756-informatsijne-povidomlennya-pro-provedennya-kruglogo-
stolu-na-temu-zona-vidchuzhennya-sogodennya-ta-majbutne
81. SAUEZ, 2015b. Official site of the State Agency of Ukraine for Exclusion Zone.
/http://dazv.gov.ua/news/770-urochista-peredacha-insineratora/
82. Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). 2000. Sources and
Effects of Ionizing Radiation (Report to the General Assembly). United Nations, New York.
83. Smith J. T. 2008. Comment. Is Chernobyl radiation really causing negative individual and
populationlevel effects on barn swallows? Biol. Lett. 4, 63–64.
84. SSSAR-2005, 2005. Sanitary standard of specific activity of radionuclides 137Cs and 90Sr in
wood and products of wood. Approved by the Ministry of Health of Ukraine, Decree No 73
on 31/10/2005, 3 pp. (in Ukrainian)
85. Steinhauser G., Brandl A., Johnson T. E. 2014. Comparison of the Chernobyl and
Fukushima nuclear accidents: A review of the environmental impacts. Science of the Total
Environment 470–471: 800–817.
86. Stohl A., Seibert P., Wotawa G. 2012. The total release of xenon-133 from the Fukushima
Dai-ichi nuclear power plant accident. Journal of Environment Radioactivity 112:155–159.
87. Talerko, N.N. 1990. Calculation of radioactive admixture release from the accidental unit of
Chernobyl power plant. Meteorology and hydrology 10: 39–46. (in Russian)
88. The Academy of Sciences of the USSR 1992. The Concept of Population Habitation in
Areas Affected by the Chernobyl Accident. 1992. Decree number 164 of April 8, 1991
Approved by the Cabinet of Ministers, Nuclear power. Questions and answers. 48 pp.
89. The Atlas of recent and predictable aspects of consequences of Chernobyl accident on
polluted territories of Russia and Belarus (ARPA Russia-Belarus). 2009. (eds. Yu.A. Izrael
& I.M. Bogdevich). Foundation "Infosphere" - NIA-Nature, Moscow-Minsk, 140 pp.
90. The Catalog of average annual effective doses at inhabitants living on contaminated
territories of the Republic of Belarus. 2015. Approved by the Ministry of Health of the
Republic of Belarus on 08/18/2015. Repablican Scientific Center for Radiation Medicine
and Human Ecology, Gomel, 86 pp.
91. Tsybulko N.N. 2015. Deputy Head of Department in the aftermath of the Chernobyl disaster
Ministry of Emergency Situations of the Republic of Belarus. Pers. comm.
58
92. UIAR, 2015. Official site of the Ukrainian Institute of Agricultural Radiology.
http://www.uiar.org.ua/
93. Ukrainian radiation protection society. Problems of revival in conditions of post-Chernobyl
syndrome. 3/17/2014. http://urps-notices.blogspot.com/2014/03/problemy-vidrodzhennja-v-
umovakh-postchornobyljskogho-syndromu.html (in Ukrainian)
94. United Nations Scientific Committee on the Effects of Atomic Radiation, UNSCEAR, 2008.
2011. Sources and effects of ionizing radiation. Report to the General Assembly with
Scientific Annexes, vilume II, Annex D. Health effects due to radiation from the Chernobyl
accident. United Nations, New York, 178 pp.
95. Verkhovna Rada of Ukraine. On Amendments and Ceasing to be Invalid Some Legislative
Acts of Ukraine. 2015. Bulletin of Verkhovna Rada 6: Paragraph 40.
http://zakon5.rada.gov.ua/laws/show/76–19 (in Ukrainian).
96. Verkhovna Rada of Ukraine. On the Concept of the Population Habitation in the Territory of
the Ukrainian SSR with Elevated Levels of Radioactive Contamination from the Chernobyl
Accident. Resolution of the Supreme Soviet on 27 February, 1991 No 791-XII. 1991.
Bulletin of Verkhovna Rada 16: paragraph 197.
http://zakon3.rada.gov.ua/laws/show/79http://zakon3.rada.gov.ua/laws/show/791-121–12
(in Ukrainian).
97. Verkhovna Rada of Ukraine. On the Legal Regime of the Territories Exposed to Radioactive
Contamination in Consequence of the Catastrophe at the Chernobyl NPP. The Law of
Ukraine is being entered into force by the Supreme Council Decree No 795–12 of the
Supreme Soviet on 28/02/91. 1991. Bulletin of Verkhovna Rada 16: paragraph 199.
http://zakon2.rada.gov.ua/laws/show/791%D0%B0–12 (in Ukrainian).
98. Verkhovna Rada of Ukraine. On the Status and Social Protection of Citizens Suffered from
the Chernobyl Disaster, the Law of Ukraine is being entered into force by the Supreme
Council Decree No 797–12 of the Supreme Soviet on 28/02/91. 1991. Bulletin of Verkhovna
Rada 16: paragraph 201. http://zakon5.rada.gov.ua/laws/show/796–12 (in Ukrainian).
99. Verkhovna Rada of Ukraine. Resolution of Cabinet of Ministers of Ukraine number 106 on
23 July, 1991 Appendix 1. The list of the settlements referred to the radioactively
contaminated zones after the Chernobyl accident. http://zakon5.rada.gov.ua/laws/show/600–
94-%D0%BF/page (in Ukrainian).
100. Verkhovna Rada of Ukraine. Resolution of Cabinet of Ministers of Ukraine number 662 on
12 May 2004, 2004. Official site http://zakon5.rada.gov.ua/laws/show/622–2004-%D0%BF
101. Watanabe, Y., Ichikawa, S., Kubota, M., Hoshino, J., Kubota, Yo., Maruyama, K., Fuma,
Sh., Kawaguchi, I., Yoshenko, V.I & Yoshida, S. 2015. Morphological defects in native
Japanese fir trees around the Fukushima Daiichi Nuclear Power Plant. Scientific Reports 5,
doi: 10.1038/srep13232. http://www.nature.com/srep/.
102. Yoschenko, V., Kashparov, V, Melnychuk, M., Levchuk, S., Bondar, Yu., Lazarev, M.,
Yoschenko, M., Farfán, E., Jannik, G. 2011. Chronic irradiation of Pinus sylvestris in the
Chernobyl exclusion zone: dosimetry and radiobiological effects. Health Physics 101: 393–
408.
103. Yoschenko, V.I., et al. 2006a. Resuspension and redistribution of radionuclides during
grassland and forest fires in the Chernobyl exclusion zone: part I. Fire experiments. Journal
of Environmental Radioactivity 86(2): 143–163.
104. Yoschenko, V.I., Kashparov, V.A., Levchuk, S.E., Glukhovskiy, A.S., Khomutinin, Yu.V.,
Protsak, V.P., Lundin, S.M., Tschiersch, J. 2006b. Resuspension and redistribution of
radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part II.
Modeling the transport process. Journal of Environmental Radioactivity 87(3): 260–278.
59