Radioactive Contamination of Food in Stepanivka Village, Zhytomyr Region,
Ukraine: in 1992 and in 2001
Volodymyr TYKHYYInstitute of Mathematical Machines and Systems, the National Academy of Science of Ukraine
42 Glushkova str., Kyiv 187, Ukraine: eeic@gluk.org

Abstract
Two series of measurements of radioactive contamination in food samples were performed in
1992 and in 2001 in a village contaminated by the Chernobyl accident. The village, Stepanivka islocated 120 km to the west of Chernobyl NPP and has a typical level of Cs-137 surface contamination
around that area (3 – 5 Ci/km2). The study was performed by the Independent Environmental
Laboratory in Kyiv, jointly founded by the Ukrainian NGO "Green World", Greenpeace International
and the International Renaissance Foundation.
It is shown that the Cs-137 contamination in milk in 2001 became 9 times lower than in 1992,
while the Cs-137 contamination in wild mushrooms and berries remained at the same level. Annual
intake of Cs-137 by the people in Stepanivka through food products and water was about 3 times lower
in 2001 than in 1992. On the contrary to the trend of Cs-137, activity of Sr-90 in milk and dried berries
was significantly higher in 2001 than in 1992.

1. Introductory note
The idea of the study was not merely scientific, but included also a social aspect. In 1992, generalpublic usually did not trust "official" data on radioactive contamination because the Soviet era attempts ofhiding the consequences of the Chernobyl disaster were still fresh in memory. Thus the results of an
independent laboratory which was run by non-governmental organizations with strong "green" reputation
would have an important social value. At that time (1991-1992), as became clear from later publications,many scientific organizations were studying radioactive contamination of food, but very few results werepublished yet. Of course, there were no attempts to make the results of the investigations available andunderstandable for general public. Only later results of investigation were presented at conferences, see, forexample, [1].
The first research was undertaken in spring-summer of 1992 by the Radiological Laboratory ofGreenpeace Ukraine (this laboratory was a joint project by Greenpeace International, Ukrainian NGO"Zelenyi Svit (Green world)" and the Kyiv-based International Renaissance Foundation. Part of theequipment was donated to "Green world" by two German universities).
The idea of the study included "on-site" measurements of food samples. This was very important torelieve possible feeling of insecurity in local communities. On-site measurements were possible because thelaboratory possessed portable gamma-radiation monitors LB200 (manufactured by Berthhold, Germany)with the low limit of Cs-137 detection in 0.5-0.8 kg samples. Indeed, the attitude of the villagers was rather
negative when the investigation began: "you are just another team that will fool us". Later we managed tobuild their trust. The people of Stepanivka and other villages nearby were informed about the results of the1992 study through local newspaper and at various meetings.
The second research was conducted in summer of 2001, owing to a support from the grant of theMinistry of Education of Japan. The study would reveal some changes (first of all - radioactive
contamination of food) that took place in Stepanivka village during almost 10 year period.
For both studies, analyses of Cs-137 and Sr-90 were performed by the Laboratory of the Radiation
97

Hygiene of the Ukrainian Institute of Hygiene and Medical Ecology. Cs-137 was measured using Camberra
Ge spectrometer with the lower limit of detection 0.17 Bq (for 10,000 sec measurement). Sr-90 was detectedby Y-90 radiochemical method.
2. General information
Village Stepanivka is located 120 km to the west of Chernobyl NPP. In 1992, there lived 369 people,
including 75 children and 108 retired people. In 2001, the population slightly decreased and became older:
45 children, 145 retired. The main enterprise in the village is a collective (in 1992 - state) farm that produces
milk, potato, hops and some other crops. Most officials (director of the farm, village Council Head,radiologist, agronomist) have been working in the same positions since 1992. Villagers have cows in private
sector and produce potato and vegetables in their vegetable gardens for their own consumption. In 1992,
many people collected and ate mushrooms (8 families out of 25 interviewed) and berries (15 out of 25) fromnearby forests. They indicated that they were eating less mushrooms and berries than before the Chernobyl
accident, because they knew about radioactive contamination. Several families ate fish from the small river
Zherev.
Soils in the vicinity of the village are light sour turf-podzol and grey, with pH from 4.6-5.5. Soilsamples were taken on plowed fields, from the upper layer 0-20 cm (same fields in 1992 and 2001). Several
samples collected in 1992 by 5 cm layers showed a uniform distribution of radioactivity. In 2001, radiationlevels on sites varied between 0.06 - 0.13 µSv h-1. Radioactive contamination of soil in 1992 and 2001 issummarised in Table 1.
The results of measurement of radioactive contamination of soil are close to the data provided by thelocal agrochemical service (surface contamination by Cs-137 between 3 - 5 Ci/km2). Thus Stepanivka could
be considered as a typical village for the areas not located directly on the so-called “Western plume ofChernobyl contamination”.
Dietary habits and local food consumption were investigated in 1992. Out of 100 families, 25 wereinterviewed (10 of them had children). Average consumption of main locally produced food products perperson is summarised in Table 3. Milk products (usually - white cheese and sour cream) were re-calculated
into milk (with the assumption that milk products retain all radioactivity that was in milk). The diet(milk-based) is characteristic for this region of Ukraine [2]. In 2001, the consumption patterns were thesame. Bread, other cereals, fruits, soft drinks and beer are imported from different regions of Ukraine, andwere not included in the study. In Table 3 we also included values of permissible levels (regulations of1997) for Cs-137 and Sr-90 in food products included in the study [3].
Samples were collected and measured first on-site using LB200 gamma monitor (in 1992), and later ina laboratory. In 2001, on-site measurements were impossible due to low activities of samples. In 1992, milk
samples were collected in two more villages of the same region.
Table 1. Soil contamination in and around Stepanivka.
Cs-137Year

Sr-90

Number ofsamples

Activity (range),
Bq/kg

Number ofsamples

Activity (range),
Bq/kg

1992

10530

334

2001

4485 (250-825)

2

3.8 (2.0-5.5)

98

3. Results and discussion
Water. Two types of drinking water supply are used in the village: centralised supply from 120 m deep
artesian well and private water wells 1 - 3 m deep. Some people use both pipeline water and wells. Waterfrom artesian well was rather radioactive (total gamma-activity by LB200 monitor about 100 Bq/1 apparently radium, thorium and their daughter products - the region is known for its granite deposits).
Average gamma activity of water in private wells (measured by LB200) was 59 Bq/1, ranging from 0 - 179
Bq/1. In this research, we had no opportunities for investigation of radioactivity of drinking water in details.
In 1999, in the other study of villages in the same Polisse region and with similar level of radioactive
contamination of soil (Cs-137 1.1 - 3.9 Ci/km2), Cs-137 activity of water in wells varied from 0.06 - 2.6 Bq/l[4]. According to this study, activity of water in 1992 was 9 times higher than in 1999.
Milk. Results of analyses of milk are presented in Table 2. Average contamination of milk with Cs-137 in
2001 was 9 times lower than in 1992. In our study, in 1992 average activity of five samples of hay was 500
Bq/kg (dry weight, measured by gamma-monitor LB200) and in 2001 activity of Cs-137 in two samples of
hay were 1,125 and 711 Bq/kg. It is not possible to conclude what is the main source of radioactive
contamination of milk - more detailed studies are needed.
Radioactive contamination of food samples is summarised in Table 3.
Meat, poultry, eggs and fish. Only several samples of meat, poultry, fish and eggs were available formeasurements, because these food products are scarce and people plan their consumption (usually this isconnected with seasonal or family celebrations, and even in these periods they are not in abundance).
Potato is very important as a food product and also as forage for pigs and chickens. All consumed potato is
produced locally, and daily consumption for food is higher than the average for Ukraine (0.63 and 0.36kg/day, respectively).
Mushrooms and berries. Fresh, canned, dried mushrooms (many different species) and berries (mainlyblackberry Vaccinium Myrtillus) are very important food products in Stepanivka. Most people harvest themin forests and eat. People know that these products are radioactive, but they constitute very significantadditives of protein (mushrooms), minerals and vitamins (berries) that are unavailable from other sources.
When filling up interview sheets in 1992, we re-calculated fresh and canned berries into dry berries. In 2001,
consumption of mushrooms and berries was apparently higher than in 1992, but we used the same figures
for our calculations.
Calculation of intake of radionuclides. The results of calculation of intake of Cs-137 and Sr-90 from themain food items in the investigated area are presented in Table 3. The shares of Cs-137 intake from the mainfood products are plotted on two diagrams in Fig.1.
Table 2. Average activity of Cs-137 in milk samples, Bq/l; n - number of samples.
19922001

Cs-137

Villagen
Stepanivka

51

Dibrova

14

RudniaRadovelska

19

Activity(range)228(28-940)71(14-150)298(45-720)

Sr-90
n

Cs-137

Activityn

Activity(range)25.5(7.1-43.8)

Sr-90
n

6

0.34

10------------

99

4

Activity(range)1.00(0.74-1.37)

Table 3. Permissible levels of contamination (PL) and activity (Bq/l or Bq/kg) of water and food in Stepanivka, and average annual intake(Bq). Absent data are marked "na".
Cs-137
Consumption(kg/pers/year)

PL(Bq/l, kg)

Sr-90

1992
Activity(Bq/l, kg)

2001
Intake(Bq)PL(Bq/l, kg)

1992

Activity(Bq/l, kg)

Intake(Bq)Activity(Bq/l, kg)

0.05

182na

2001
Intake(Bq)Activity(Bq/l, kg)

Intake
(Bq)

0.25

91

1.0

256

Water

365

2na

Milk

256

100

210

53,800

25.5

6,528

20

0.34

Meat,poultry

80

200

62

5,000

43.9

3,512

20na

0.540

Fish

0.6

150

330

200

472835na

2.2

1.3

Eggs
(pieces)

300

6

1.5

450

na

2na

na

Potato230

60

122,800

14.9

3,427

20

na

0.5

115

Drymushrooms

0.7

2,500

30,50021,30020,047

14,033

250

na

4.8

3.4

Dry berries

0.3

2,500

18,0005,400

17,650

5,295

250

4.5

56.6

17

Total intake from local food

88,95032,841**Including water

100

87

1.4523*

Annual intake of Cs137 with local food in 1992
(total 88 kBq)

6%
24%

Milk
Meat
PotatoMushrooms
Berries

61%

3%
6%

Annual intake of Cs137 with local food in 2001(total 33 kBq)

16%

20%

11%
10%

43%

Milk
Meat
PotatoMushrooms
BerriesFig.1. Intake of Cs-137 from main food sources.
Discussion
From the results of our study it is clear that average intake of Cs-137 in 2001 is almost three times
lower than in 1992: 89 kBq and 33 kBq, respectively. In 1992, milk contamination accounted for 61 % ofannual intake of Cs-137, and mushrooms and berries accounted for 30 % together. In 2001, the share of milk
dropped to 20 % and the share of mushrooms and berries became 59 %. The content of Cs-137 in berries andmushrooms has been more or less stable in 1992-2001, as it was also shown in other studies (see, forexample, [5] for the period 1991-1999).
Our results prove that Stepanivka is located in a rather "good" area, because in many other villages(even to the west of Stepanivka) radioactive contamination of milk remains significantly higher. In 1998,
out of 34,233 samples of private sector milk in Ukraine, contamination of 19.7 % of them with Cs-137 washigher than permissible level 100 Bq/l [6].
It is also clear that contamination of food with Sr-90 increased significantly: almost three times formilk and 12 times for dry berries. There exist numerous investigations which show that the migration ofSr-90 in plants increases with time due to chemical transformations of deposited fuel particles. (See, forexample, a paper by Yu.O.Ivanov with quite comprehensive bibliography [7]).
In 1992, we used (to make a rough estimate) the results presented by Smoliar [2] that an intake of eachkBq/year of Cs-137 results in an annual dose of 0.011 mSv/year. In this case the average dose in Stepanivka(from locally produced food) was 1.2 mSv/year in 1992. This dose was lower than 1992 permissible level of
5 mSv/year.
Later, several regulations on calculation of internal doses from food and other sources were publishedby international organizations and in Ukraine [see, for example, 8]. But, if we use the same assumption by
Smoliar for Cs-137 intake results of 2001, then the annual dose from local food would be 0.37 mSv/year,101which is lower than the permissible radiation dose for population - 1 mSv/year, stipulated by National
Radiation Protection Norms. Of course, this calculation does not account for doses from incorporated
strontium and alpha-emitters, as well as for inhalation and external irradiation doses. As it is shown in [3],for people living in similar environment, internal irradiation from food contamination by Chernobyl
radionuclides comprises only about 40 % of the total internal dose, while 60 % of internal dose is formed bynatural radionuclides such as Rn and Tn and their daughter products (results of the 1996-1997 studies; thepaper provides a breakdown of the total intake of Cs-137 and Sr-90 from various food products).
It should be noted, however, that we did not investigate patterns of individual intake of radionuclides,
which vary very significantly even for people living in the same village.
Acknowledgements
The paper was discussed and recommended for publishing at the Laboratory of Radiation Hygiene of
the Institute of Hygiene and Medical Ecology of the Academy of Medical Science of Ukraine.
The author expresses his gratitude to Prof. Edmund Lengfelder from Munich University who organizeddonation of equimpent to Ukrainian Ecological Association "Green World" in 1990, Dr. LyudmilaNagovitsyna from Ukrainian Scientific Hygien Center, and Imanaka Tetsuji from Kyoto Research Reactor
Institute for the support of the second stage of the study.
The author also thanks the people of Stepanivka village and Luginy district, first of all Mykola
Kaminsky, the Head of the village Council and Yuri Grinevytch, teacher, and Volodymyr Prekrasny andVolodymyr Ovdienko who participated in field expeditions and measurements.
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