Chernobyl fallout: Swedish bank voles


Scenario 

     Field rodents, bank voles (Clethrionomys glareolus Schreb) were collected from three differently contaminated forest areas and one negligible ground deposition of radionuclides as controls in south-eastern Sweden. For small animals, direct contact with ground deposited fallout and the ingestion of contaminated food are sources of external and internal irradiation.

     A total of 104 field mice were captured during July-August 1988 with traps using high-quality, uncontaminated baits. Sex, age and somatic features were determined. After removal of skulls and digestive organs, the carcasses were weighted, homogenized and the radionuclide body burden was determined.

     Femurs were dissected, their bone marrow cells were flushed out, and the frequencies of micronucleated polychromatic erythrocytes (MPCEs) were studied in 2000 polychromatic erythrocytes (PCEs) for each individual. In order assess any toxicity effects, the frequency of normochromatic erythrocytes (NCEs) was also counted and PCE/NCE ratio was determined. 

Reference 

     Cristaldi, M., Ieradi, L. A., Mascanzoni, D. and Mattei, T. (1991): Environmental impact of the Chernobyl accident: mutagenesis in bank voles from Sweden. Int. Nat. J. Radiat. Biol., 59:31-40. 

Micronucleus assay in bone marrow polychromatic erythrocytes 
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. Site Ground deposition No. of Body burden (Bq/kg) Whole body dose rate*, (ƒÊGy/day) Bone marrow micronucleus assay
137Cs animals 134Cs 137Cs 134Cs 137Cs Total** MPCE/1000PCE PCE/NCE
(Bq/m2) collected mean SD SE mean SD SE ƒÁE ƒÁI ƒÀI ƒÁE ƒÁI ƒÀI mean SD SE mean SD SE
1 1,800 22 9 10 2 39 54 11 0.04 0.01 0.02 0.05 0.01 0.10 4.23 1.3 1.4 0.3 0.97 0.29 0.06
2 22,000 22 279 193 41 1,031 636 136 0.49 0.17 0.61 0.65 0.25 2.66 8.83 1.5 1.2 0.3 1.19 0.27 0.06
3 90,000 22 1,356 872 186 5,119 3,315 707 1.88 0.82 2.96 2.65 1.27 13.21 26.79 1.9 1.7 0.4 1.26 0.40 0.09
4 145,000 38 2,151 2,322 377 7,784 8,169 1,325 3.06 1.31 4.70 4.28 1.92 20.09 39.36 2.6 1.4 0.2 1.47 0.53 0.09
*) ƒÁE: external gamma-rays. ƒÁI: internal gamma-rays. ƒÀI: internal beta-rays. **) Background radiation of 4.0 ƒÊGy/day is included in all locations.
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