Environmental impact of the Chernobyl accident: mutagenesis in bank voles from Sweden.

An investigation was carried out in Sweden aimed at studying the possible genetic effects of the Chernobyl fallout on wild small mammals. The bank voles (Clethrionomys glareolus Schreb.) were obtained from three differently contaminated areas in Sweden and, for control, in an area with negligible contamination by fallout. Radionuclide determinations to assess the content of 137Cs and mutagenicity tests (bone marrow micronucleus test and sperm abnormality assay) were performed. The results obtained showed a positive correlation between the increase of micronucleated polychromatic erythrocytes (MPCE/1000 PCE) and both 137Cs content in muscle and in soil contamination. The estimated doses absorbed by the animals were far lower than those required for the same effect in laboratory experiments. An explanation of this discrepancy between dose and measured biological effect is not available, yet similar results have been repeatedly reported after the Chernobyl accident and should be a matter for further discussion. An increased frequency of micronucleated cells might occur at minimal dose gradients, and the micronucleus test appears to be a valid tool to show such effects.

Long-term transfer from soil to plant of radioactive corrosion products.

The uptake by swards of three activation products ((54)Mn, (57)Co and (63)Ni) was studied in a long-term field experiment. Some of the soils used in the investigation were sampled in the vicinity of four Swedish nuclear power plants, while the others represented the most frequent types of agricultural soils occurring in Sweden. Data on the uptake by clover and timothy during a 9-year period were used for the calculation of soil-plant transfer factors of these nuclides. The temporal distribution of the transfer factors and the variations exhibited by the different nuclides were examined, as well as the differences between crops. The increased uptake at the early stage of the experiments (first year effect) observed in clover is discussed. Regression analyses employed to quantify the dependence of uptake on soil parameters showed that the soil characteristics that most influenced the uptake are the pH and the soil contents of calcium and potassium.

Chernobyl's challenge to the environment: a report from Sweden.

This paper reports the levels of radiocesium registered in about 9000 samples collected in different parts of Sweden following the Chernobyl accident during the period May-November 1986. The maximum Cs levels were detected in reindeer, freshwater fish and mushrooms. Parameters possibly affecting the nuclide concentration in different biota are briefly discussed.

Small mammals as biological indicators of radioactive contamination of the environment.

An investigation was carried out in Sweden aimed at studying the contamination of small mammals (orders Rodentia and Insectivora) following the Chernobyl accident. The animals were captured in three differently contaminated areas in Sweden and, for control, in an area with negligible fallout. The results obtained show that the activity in the captured animals was correlated with surface deposition. The differences between the species investigated and the influence of feeding habits on the contamination levels are discussed.

137Cs determination and mutagenicity tests in wild Mus musculus domesticus before and after the Chernobyl accident.

Wild rodents were collected alive in a suburban area to the north of Rome before, during, 6 months and 1 year after the Chernobyl accident. Radionuclide determinations to assess their content of (137)Cs and mutagenicity tests (bone-marrow micronucleus test and sperm abnormalities assay) were performed on the captured animals. The results obtained for the species Mus musculus domesticus (which was the rodent captured in highest numbers), compared with the results obtained before the fallout, showed an increase of both micronucleated polychromatic erythrocytes (MPCEs/1000 PCEs) and (137)Cs content during and after the fallout.

Genetic damage in urban mice exposed to traffic pollution.

Wild rodents (Mus domesticus) were collected in three areas in Rome exposed to different traffic flows to ascertain a possible correlation between genetic damage and heavy metal concentration. The concentration of lead, cadmium and zinc were determined in liver, kidney and bones and two mutagenicity tests (micronucleus test and sperm abnormality assay) were employed. The results obtained showed that the contents of lead and cadmium were higher in animals collected in areas with high traffic flows than in those from control areas. A statistically significant increase of the frequency of micronucleated erythrocytes and of abnormal sperm cells was also obtained in animals collected in sites with high traffic flows. The investigation confirmed the suitability of using wild rodents as bioindicators of environmental pollution and as key-organisms in programs of pollution monitoring and environmental conservation.

Predicting the radionuclide fraction transferred to consumption through grain foods.

Data on the root uptake by wheat of three activation products, 54Mn, 65Zn and 63Ni, and two fission products, 90Sr and 137Cs, were obtained in a long-term field study. Soil-plant transfer factors calculated from these data were used to determine the amount of various radionuclides that may reach the humans through grain foods. The temporal variation of this contribution showed that the fraction of 54Mn and 65Zn transferred to human consumption during the first year was considerable, but owing to decay and decreasing uptake the gradients diminished and the accumulated fraction flattened to a plateau. In contrast, the fractions of the long-lived 63Ni, 90Sr and 137Cs transferred to human consumption were smaller and with nearly constant gradients. This study shows that the long-lived radionuclides are transferred to the same extent as 54Mn and 65Zn. In the long-term, the greatest doses from grain products are contributed by the long-lived radionuclides.

Environmental impact of the Chernobyl accident : mutagenesis in bank voles from Sweden

An investigation was carried out in Sweden aimed at studying the possible genetic effects of the Chernobyl fallout on wild small mammals. The bank voles (Clethrionomys glareolus Schreb) were obtained from three differently contaminated areas in Sweden and, for control, in an area with negligible contamination by fallout. Radionuclide determinations to asses the content of 137Cs and mutagenicity tests (bone marrow micronucleus test sperm abnormality assay) were perfomed. The results obtained showed a positive correlation between the increase of micronucleated polychromatic erythrocytes (MPCE/1000 PCE) and both 137Cs content in muscle and in soil contamination. The estimated doses absorbed by the animals were far lower than those required for the same effect in laboratory experiments. An explanation of this discrepancy between dose and measured biological effect the Chernobyl accident and should be a matter for further discussion. An increased frequency of micronucleated cells might occur at minimal dose gradients, and the mocronucleus test appears to be a valid tool to show such effects(AU)