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Journal of Environmental Radioactivity 127 (2014) 171e175

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Journal of Environmental Radioactivity

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Accumulation and distribution of 137Cs and 90Sr in the body of the wildboar (Sus scrofa) found on the territory with radioactivecontamination

Andrey Vladimirovich GulakovFrancisk Skorina Gomel State University, Gomel, Belarus

a r t i c l e i n f o

Article history:Received 1 June 2011Received in revised form14 June 2013Accepted 18 June 2013Available online 17 July 2013

Keywords:Wild boar137Cs90SrThe Chernobyl disaster

E-mail address: gulakov.andr@yandex.ru.

0265-931X/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.jenvrad.2013.06.008

a b s t r a c t

We studied the concentration and distribution of 137Cs and 90Sr in the bodies of 188 wild boar (Sus scrofaLinnaeus, 1758) taken near the Chernobyl site. Of these, 111 animals were taken in the Alienation Zone, 41animals were taken in the Permanent Control Zone and 36 animals were taken in the Periodic ControlZone. The samples included muscle and bone (rib) tissues and samples of heart, liver, lungs, kidneys,spleen, genitals and skin. The weight of the samples was 0.5 kg fresh weigh. The average concentration of137Cs in the muscles of the wild boar found in the Alienation Zone was 46 � 10 kBq/kg, in the PermanentControl Zone e 13 � 3.0 kBq/kg and in the Periodic Control Zone e 0.6 � 0.1 kBq/kg. The largest con-centration of 137Cs was detected in the muscle tissue and kidneys taken animals. In some samples ofmuscle tissue it reached more than 660 kBq/kg. The 137Cs concentrations were also high in heart andspleen up 64.3 kBq/kg and 67.5 kBq/kg e animals from the Alienation Zone and 10.3e10.6 kBq/kg e

animals from the Permanent Control zone. The lowest concentration of 137Cs was found in the lungs andskin of animals. The analyses of 90Sr concentration in the organs and tissues of the wild boar showed that90Sr was concentrated mainly in the bone tissue. The average level of 90Sr concentration in bone was17.6 kBq/kg fresh weight animals from the Alienation Zone and 13.47 kBg/kg e animals from the Per-manent Control zone. In muscle tissues and organs contained 90Sr e 30.0e110.0 Bq/kg in the AlienationZone and 11.0e30.0 Bq/kg in the Permanent Control zone.

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1. Introduction

During the time of the nuclear power development there havebeen some nuclear disasters but the Chernobyl disaster is the mostsevere among them. Ecological problems that followed the disasterare very diverse. Radiocaesium released after the Chernobyl nu-clear power plant accident caused a total ground contaminationmost of the territory Republic of Belarus. The Chernobyl accidenthas no analogs in both area of radioactive contamination andabsorbed doses to biota species. The total release of fission products(ignoring inert radioactive gases) was estimated to be1.85 � 1018 Bq (IAEA, 2006).

As a result of the contamination of the natural environmentfrom the Chernobyl nuclear power plant, the human populationwas evacuated and this formed new and in its way uniqueecological niches with free living space for the settlement of rep-resentatives of macro fauna. Wild ungulates are an essentialcomponent of forest biocenosis and as herbivores can serve as

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reliable indicators of the degree of pollution. In Belarus, wild boarsare common (Savitsky et al., 2005). Wild animals can representmajor sources of radiation exposure to humans. The contaminationof the meat of wild boar with 137Cs has been studied by severalauthors (Putyrskaya et al., 2003; Hohmann and Huckschlag 2005;Vilic et al., 2005; Steiner and Fielitz 2008).

The mechanism of radionuclide penetration into the animalbody, the distribution of these radionuclides among organs andtissues and the speed of excretion of the body determine theradiological impact. Chronic effects of radionuclides in the body ofanimals will continue for a long time. There are several importantanimal pathways for radionuclide transfer to the diet of humans.The most important for many contamination scenarios for radio-logically important radionuclides 137Cs and 90Sr is milk consump-tion, but muscle consumption is also a significant source for someradionuclides (Annenkov et al., 2004). Therefore, quantification ofthe transfer of radionuclides through foodchains to humans haslong been a key focus of radiation protection (Pröhl et al., 2006;Strebl and Tataruch 2007).

The concentration of 137Cs in different components of a forestecosystemdepends on the level of area contamination, radionuclide

Table 1Concentrations of 137Cs in the muscle tissue of the wild boar found in the Alienationzone, giving the mean � the standard error of the mean, the minimum andmaximum and the coefficient of variation (standard deviation/mean).

Year Number ofanimals

The concentration of 137Cs in themuscle tissue, kBq/kg fresh weight

Coefficient ofvariation, %

Mean � SE Min Max

1991 3 12 � 0.96 10 14 141992 4 120 � 87 10 381 1461993 9 19 � 4.5 1 38 721994 6 104 � 61 2 366 141995 2 40 17 62 801996 3 240 � 210 8 661 1491997 3 52 � 31 3 65 1041998 3 10 � 1.95 6 13 331999 4 170 � 140 6 589 1702000 3 11 � 4.2 4 19 672001 2 7 4 9 542002 7 5 � 2.0 1 14 962003 6 11 � 2.54 6 19 582004 5 16 � 11.1 3 61 1532005 13 21 � 7.53 1 70 262006 8 30 � 19.9 1 166 302007 20 33 � 7.70 2 116 332008 10 37 � 22 1 217 37

A.V. Gulakov / Journal of Environmental Radioactivity 127 (2014) 171e175172

bioavailability and on the individual abilities of species to accumu-late 137Cs. Therefore, wild animals inhabiting the same forest havevery different levels of 137Cs meat contamination. Therefore thestudy of the features of accumulation and distribution of radionu-clides, the identificationof species, sex, age, and seasonal differencesin the concentration of radionuclides in the body of wild animalsliving in polluted biogeocenosis will be both scientific and practicalinterest. In addition, the gifts of nature, including the meat of wildungulates can be an additional source of radionuclides in the humanbody and lead to an increase in radiation dose to the populationliving in the contaminated area. In this connection is required toexamine the levels and dynamics of radionuclide contamination ofthe body of game animals.

2. Materials and methods

The monitoring of distinct populations of wild hunting animalwas carried out on the territory of Belarusian Polesie. It occupies anarea more than 6.1 million hectares, or 30% of the total land-usearea of the Republic of Belarus (Ilina et al., 1998). The mostcontaminated area is situated in the Alienation Zone near the vil-lages of Borschevka, Molochki, Pogonnoe, Radin, Arevichi andDroniki. The villages lie in the Choyniki district, Gomel region. The137Cs contamination level here is 1100e8184 kBq/m2 and 90Sr e

185e1633 kBq/m2. The territory where samples were collected issituated between the rivers the Prypyat and the Dnieper that is 10e35 km from Chernobyl Nuclear Power Station.

We have also taken samples in the Permanent Control zone inBragin district, Gomel region near the villages of Savichi, Puchinand Zherdnoe. The contamination density of this land is e 137Cs e185e1480 kBq/m2 and 90Sr e 74e420 kBq/m2. This territory issituated between the rivers the Prypyat and the Dnieper that is 30e35 km from Chernobyl Nuclear Power Station.

The Periodic Control zone is the territory of the Gomel districtnear the village of Kravtsovka lying on the border with Chernigovregion of the Ukraine on the river Sozh, that is a tributary of theriver Dnieper. This territory lies at a distance of 40 km from the cityof Gomel and approximately 100 km from Chernobyl Nuclear Po-wer Station. The contamination level is e 137Cs e 18.5e37.0 kBq/m2

and 90Sr e 1.0e1.85 kBq/m2.We took the samples on the tested territory twice a year e in

winter (DecembereFebruary) and in summer (JulyeAugust). Theseperiods show the most obvious seasonal changes in the levels ofcontaining radioactive elements in the food and bodies of wildungulates. In winter we got all the animals in the morning beforenoon. If there was not much snow, the animals were brought to bayor were shot when approaching. In summer the animals were killedmainly at night or early in the morning while feeding. All capturedanimals have been shot with a hunting weapon.

In total, we took samples from 188 animals found on the terri-tory with various densities of radioactive contamination. Amongthese 111 animals were shot in the Alienation Zone, 41 e in thePermanent Control zone and 36 e in the Periodic Control zone. Theextracted animals do not have other injuries besides bullet wounds.

We retained samples of muscle and bone (rib) tissues and of theheart, liver, lungs, kidneys, spleen, genitals and the skin. Hereafterall the values were calculated on a fresh weight basis. Wemeasuredthe activity concentration of 137Cs in the organs and tissues of thewild animals on the gamma-beta-spectrometer MKC-AT1315(minimal tested activity is not less 2 Bq/kg in geometry 1.0 l(Marinelli), the registration effectiveness of energy 661 keVe2.46 � 10�2 MMF/quantum (MMF e Measuring of Magnetic Field),the energy range of registered g-radiation from 50 to 3000 keV)and on gamma-radiometer PLG-AT1320A (minimal tested activitye 3.7 Bq/kg, the registration effectiveness e 2.2 � 10�2 MMF/

quantum). The measuring inaccuracy is not more than 15%. Thedifferences in equipment indexes (spectrometer, radiometer) whentested again were not more than 4% (Shevchyuk, 1998). 90Sr wasmeasured using a radiochemical method according to basicmethods (Derzhavin, 1985) and using b-meter Canberra-2004.

The data were processed with Statistica 8 and Microsoft Excelprograms. Whether on not the data fitted the normal distributionhad been determined beforehand. Logarithms were taken of thevalues when needed. The data were then treated by regressionanalysis and analysis of variance (ANOVA).

3. Results and discussion

3.1. The evolution of 137Cs concentration in the muscle tissue of thewild boar

The most important fluctuations of 137Cs concentration in themuscle tissue of the wild boar were detected in the Alienation Zone(Table 1). The average concentration of 137Cs in the muscle tissue ofthe wild boar found the Alienation Zone among the years sampledfluctuated from 10.0 kBq/kg to 243 kBq/kg. The minimum con-centration was 1.0 kBq/kg and the maximum concentration e

661 kBq/kg. This wide range is because the level of contaminationof the land and the food is not the same everywhere, especially inthe Alienation Zone, and it is also connected with the high migra-tion of animals. In the past years the tests have shown that 137Csconcentration in the bodies of animals was 30.0 kBq/kg e 37.0 kBq/kg (Gulakov and Saevich, 2006; Gulakov, 2008). The average con-centration of 137Cs in themuscle tissue of thewild boar found in theAlienation Zone during the sampling was 49.7 � 15.4 kBq/kg. Thereason for the absence of decrease in 137Cs concentration in themuscle tissue of ungulates in recent years is due to the constantlevel of radioactive contamination of food supply.

The concentration evolution of 137Cs in the muscle tissue of thewild boar in the Permanent Control zone was very similar to theanimals found in the Alienation Zone (Table 2). However, the con-centration level of 137Cs in the muscle tissue was much lower. Theminimal concentration in muscle tissue was detected in the animalgot in 1993e0.4 kBq/kg, and the maximum was in 1996e105 kBq/kg (the difference is more than 284 times). In recent years 137Cs

Table 2Concentrations of 137Cs in the muscle tissue of the wild boar found in the Permanentzone, giving the mean � the standard error of the mean, the minimum andmaximum and the coefficient of variation (standard deviation/mean).

Year Number ofanimals

The concentration of 137Cs in themuscle tissue, kBq/kg fresh weight

Coefficient ofvariation, %

Mean � SE Min Max

1991 2 1 1 2 261992 3 10 � 2.18 6 13 391993 3 2 � 1.66 0.4 6 1271994 4 16 � 8.64 4 41 1071995 5 11 � 2.37 6 20 491996 9 33 � 12.5 0.6 105 1141997 5 18 � 7.15 4 36 881998 4 6 � 1.51 2 9 501999 2 6 5 6 52000 4 5 � 1.79 0.5 9 101

Table 4137Cs activity in the muscle tissue of the wild boar found on the territory withradioactive contamination, kBq/kg.

Region The content 137Cs in a muscular tissue, kBq/kg

Mean � SE Min Max Range

The alienation zone 46 � 10 0.5 661 660.5The permanent control zone 13 � 3.0 0.3 105 104.7The periodic control zone 0.6 � 0.1 0.1 2.4 2.3

A.V. Gulakov / Journal of Environmental Radioactivity 127 (2014) 171e175 173

concentrations in animal bodies got in the Permanent Control zonewere 5.0e6.0 kBq/kg. The average concentration of this radioactiveelement in the muscle tissue of the wild boar got in the PermanentControl zone for the whole period of testing was 12.8 � 3.1 kBq/kg.This is 3.9 times lower (P < 0.05) than in the animals from theAlienation Zone. The coefficient of variation was from 5% to 127%.

The animals found in the periodic control zone had relativelylow 137Cs concentrations in their bodies (Table 3). The averageconcentration level was 0.3e0.9 kBq/kg during the period oftesting. The minimum 137Cs concentration in the muscle tissue wasdetected in the animal got in 2000 e 0.1 kBq/kg, the maximumconcentration in 1998 e 2.4 kBq/kg (the differences are 20 times).The coefficient of variation was 16%e112%.

The average 137Cs concentration in the muscle tissue of the wildboar got in the Periodic Control zone during the whole period oftests made up 0.6 � 0.1 kBq/kg. That is 88.7 times lower (P < 0.05)than in the animals got from the Alienation Zone and 28.8 timeslower (P < 0.01) than in the animals got in the Permanent Controlzone. It should be mentioned that animals with excess concentra-tion level of 137Cs in the muscle tissue were also found in the Pe-riodic Control zone.

In Table 4 we have average concentration of 137Cs in the muscletissue of the wild boar found on the territory with a different levelof radioactive contamination for all period of research. The averageconcentration of 137Cs in the muscles of the wild boar found in theAlienation Zonewas 46� 10 kBq/kg, in the Permanent Control Zone

Table 3Concentrations of 137Cs in the muscle tissue of the wild boar found in the PeriodicControl zone, giving the mean � the standard error of the mean, the minimum andmaximum and the coefficient of variation (standard deviation/mean).

Year Number ofanimals

The concentration of 137Cs in themuscle tissue, kBq/kg fresh weight

Coefficient ofvariation, %

Mean � SE Min Max

1991 3 0.5 � 0.16 0.4 0.9 491992 3 0.5 � 0.19 0.4 0.6 161993 3 0.5 � 0.12 0.3 0.7 441994 3 0.5 � 0.10 0.2 0.7 541995 2 0.4 0.3 0.5 291996 3 0.7 � 0.43 0.2 1.5 1121997 2 0.3 0.2 0.4 581998 6 0.9 � 0.35 0.2 2.4 1021999 5 0.6 � 0.25 0.1 1.4 992000 4 0.4 � 0.15 0.1 1.0 842003 2 0.4 0.2 0.5 65

e 13 � 3.0 kBq/kg and in the Periodic Control Zone e 0.6 � 0.1 kBq/kg. These results show that 137Cs concentration in the muscle tissueof the wild boar changes in accordance with the contaminationdensity of their habitat. It should be noted that the more unequallycontaminated is the animal’s habitat, the greater the range in valuesobtained. The range of concentrations for the Alienation Zonemadeup 660.5, the Permanent Control zone e 104.7, and in the PeriodicControl zone e 2.3.

3.2. 137Cs distribution in the organs and tissues of the wild boar

It should be noted that the distribution and accumulationmechanism of radioactive elements in organs and tissues is well-studied but mainly for cattle (Korneev et al., 1977; Korneev andSirotkin, 1987; Sirotkin and Iljazov, 2000). The data concerningradioactive distribution and the bodies of wild animals living for along time on the territory with various densities of radioactivecontamination are not sufficient (Tataruch et al., 1990; Eriksson,1996).

As you can see, the data in Fig. 1 show that the greatest con-centration of 137Cs was in the muscles and kidneys, the concen-tration level in some animals reached more than 660 kBq/kg. Highlevels of 137Cs were also found in the heart and spleen. The 137Csaccumulation in these organs was 64.3 kBq/kg and 67.5 kBq/kg inthe animals got in the Alienation Zone and 10.3e10.6 kBq/kg in thePermanent Control zone. The lowest 137Cs concentration wasdetected in lungs and skin.

It should be noted that the 137Cs concentrations decreased fromthe Alienation Zone to the Periodic Control zone, as observed forconcentrations in muscle. The concentrations decreased:muscles > kidney > heart > liver > spleen > genitals > lungs >skin. We have done the correlation analyses of 137Cs concentrationin the muscle tissue and main inner organs of the wild boar foundon the territory with various densities of radioactive contamination(Figs. 2 and 3). As we can see from the data (Figs. 2 and 3), there areclose correlative relations with coefficients from 0.75 to 0.99, be-tween the activity concentrations in the muscle tissue and innerorgans of the wild boar.

The analyses of 90Sr concentration in the organs and tissues ofthe wild boar showed that this radioactive element in concentratedmainly in the bone tissue of animals. The average 90Sr concentra-tion in this tissue made up 17.7 kBq/kg for the wild boar got in theAlienation Zone and 13.5 kBq/kg e in the Permanent Control zone.The muscle tissue and organs contained 90Sr in the range of 30.0e110.0 Bq/kg in the Alienation Zone and 11.0e30.0 Bq/kg in thePermanent Control zone. Our data are confirmed by other scien-tists’ researches (Bogatov et al., 1980), who also noted higheraccumulation coefficients of radioactive strontium in the bonetissue in comparison to other organs.

Apart from bone tissue 90Sr is more accumulated in genitals andskin of animals. There are no reliable differences in accumulationand distribution of 90Sr among other organs and tissues of the wildboar found in the Alienation Zone and the Permanent Control zone.

0

1

10

100

Alienation zone Permanent control zone Periodic control zone

kBq/

kg

muscle heart lungs liver kidneys spleen genitals skin

Fig. 1. The average 137Cs concentration, fresh weight basis, in the organs and tissues of the wild boar found on the territory with radioactive contamination.

muscles

heart

kidneys

lungs liver

0.84

0.970.85

0.95

0.910.80 0.93

0.990.80

0.75

Fig. 2. The coefficients of linear correlation between the 137Cs concentrations in theorgans and tissues of the wild boar found in the Alienation zone.

muscles

heart

kidneys

lungs liver

0,83

0.990.89

0.82

0.980.90 0.84

0.820.98

0.90

Fig. 3. The coefficients of linear correlation between the 137Cs concentrations in theorgans and tissues of the wild boar found in the Permanent Control zone.

A.V. Gulakov / Journal of Environmental Radioactivity 127 (2014) 171e175174

4. Conclusion

The data show that there are reliable changes in 137Cs concen-tration in the muscle tissue of the wild boar depending on thedensity of contamination of the habitat. It should be noted that themore unequally is the contamination of the habitat, the larger therange in values obtained. The highest 137Cs concentration in themuscle tissue was detected in the bodies of the animals found onthe territory with a high level of radioactive contamination: up to660.0 kBq/kg in the Alienation Zone, and up to 105.0 kBq/kg in thePermanent Control zone. The analyses of 137Cs distribution in theorgans and tissues of the wild boar showed that this radioactiveelement is mainly accumulated in muscle tissue and kidneys of theanimal.

90Sr was concentrated mainly in the bone tissue of animalswhere its concentration was by 2 or 3 times higher than in otherorgans and tissues. The muscle tissue and organs of the wild boarcontain 90Sr in the range of 11.0e110 Bq/kg.

It should be noted that for the whole period of testing we gotanimals with such a 137Cs contamination level of the muscle tissuethat was higher than the above normative values. These animalswere found in the Periodic Control zone with a relatively lowcontamination level of the territory and food supply. Thus, if wewant to avoid eating the meat of wild ungulates that exceeds thelevels in 137Cs concentration, it is necessary to do radiometric sur-vey of the animals regardless of the radioactive contamination levelof the habitat.

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