Effects of radioactive contamination on Scots pines in the remote period after the Chernobyl accident

Abstract

A 6 year study of Scots pine populations inhabiting sites in the Bryansk region of Russia radioactively contaminated as a result of the Chernobyl accident is presented. In six study sites, (137)Cs activity concentrations and heavy metal content in soils, as well as (137)Cs, (90)Sr and heavy metal concentrations in cones were measured. Doses absorbed in reproduction organs of pine trees were calculated using a dosimetric model. The maximum annual dose absorbed at the most contaminated site was about 130 mGy. Occurrence of aberrant cells scored in the root meristem of germinated seeds collected from pine trees growing on radioactively contaminated territories for over 20 years significantly exceeded the reference levels during all 6 years of the study. The data suggest that cytogenetic effects occur in Scots pine populations due to the radioactive contamination. However, no consistent differences in reproductive ability were detected between the impacted and reference populations as measured by the frequency of abortive seeds. Even though the Scots pine populations have occupied radioactively contaminated territories for two decades, there were no clear indications of adaptation to the radiation, when measured by the number of aberrant cells in root meristems of seeds exposed to an additional acute dose of radiation.

Study of needle morphometric indices in Scots pine in the remote period after the Chernobyl accident

“…The results obtained confirm that both radionuclides could impact necrosis appearance, but 137 Cs is supposed to be more significant. This is in line with our previous estimates that β-radiation contributed only 0.4-9.3% to the total dose at the study sites (Geras'kin et al, 2011).…”

“…The study sites are similar in soil properties, the stands of trees are homogeneous, and pine trees as an edificator species take up a significant part of the phytocenosis. The heavy metal contents in soils and cones are within background levels (Geras'kin et al, 2011). There were two reference populations (Ref and Ref1).…”

“…Monitoring of exposure dose rates and radionuclide activity concentrations in soils and pine cones at the study sites has been provided annually since 2003. Detailed information on the radioactive contamination of the study sites can be found in (Geras'kin et al, 2011). Table 1 gives general information about the main radionuclide activities in soils and cones as well as the dose and dose rate levels at the study sites (Spiridonov et al, 2008).…”

“…Studies of the effects of radiation exposure on Scots pine populations in the initial period after the Chernobyl accident revealed death of sprouts, dying needles, reduced reproductive capacity, chromosomal aberrations and mutations in enzyme loci (Kozubov and Taskaev, 2002;Fedotov et al, 2006). In the remote period, an increased mutational and cytogenetic variability in chronically irradiated pines was shown to be significantly associated with the levels of radiation exposure (Geras'kin et al, 2011;Geras'kin and Volkova, 2014). Nevertheless, any stable effects on productivity, seed survival or adaptive capacity were not identified (Geras'kin et al, 2011).…”

“…In the remote period, an increased mutational and cytogenetic variability in chronically irradiated pines was shown to be significantly associated with the levels of radiation exposure (Geras'kin et al, 2011;Geras'kin and Volkova, 2014). Nevertheless, any stable effects on productivity, seed survival or adaptive capacity were not identified (Geras'kin et al, 2011). Moreover, information on makarenko_ek_obninsk@mail.ru the possible alterations in morphometric traits of pine trees in the contaminated territories in the remote period after the accident is virtually absent.…”