Conclusions from Chornobyl Research Projects
at Texas Tech University
Scientists from Texas Tech University have been collecting small mammals and studying the genetic effects of radiation exposure at Chornobyl since 1994.
Populations are vibrant and mammalian species diversity does not appear to be reduced, even in the most radioactive environments (Baker and Chesser, 2000; Chesser and Baker, 1996).
No birth defects or physical deformities have been detected (Baker et al., 1996).
Methods for assessment of absorbed dose from internally deposited radionuclides in small mammals were developed and applied to animals from many regions surrounding the Chornobyl reactor complex (Chesser et al., 2000).
The radiation dose received by mice annually (internal + external) often far exceeds the acute lethal dose (Chesser et al., 2000; Chesser et al., accepted).
We believe there is a risk associated with living in the most radioactive regions, but that the risk to small mammals does not appear to be great enough to counter the biological principal that more young are born than can survive (Baker et al., 1996; Baker and Chesser, 2000; Chesser and Baker, 1996).
No germline mutations were found in microsatellite DNA from exposed embryos of Apodemus agrarius (Baker et al., 1999).
We have been unable to document reproductive inhibition in several small mammal species (laboratory strains of Mus as well as native species such as Clethrionomys glareolus) exposed to 30-40 times the IAEA limits of exposure for terrestrial vertebrates (Rodgers et al., accepted; Rodgers et al., submitted; Chesser et al., accepted).
Comparison of mtDNA sequence data in voles reflects an elevated rate of mutation in comparisons of exposed individuals to reference individuals, though the difference is not statistically significant (Baker et al., 1999; Wickliffe et al., submitted).
Our data do not support genetically based radioesistance in voles living in the radioactive regions (Rodgers et al., accepted).
Uptake rates and biological loss rates of cesium and strontium in mammals has been determined (Chesser et al., accepted, in prep.).
Micronucleus formation is not elevated in exposed mice as compared to unexposed mice (Rodgers and Baker, 2000; Rodgers et al., accepted; Rodgers et al., submitted).
Genetic haplotype diversity is greater in vole populations in the most radioactive regions than in populations of voles from reference locations (Matson et al., 2000).
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