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Transfer of radioactive environmental load to the population of the wild boar (Sus scrofa) in selected localities of the south-western part of the Czech Republic
KOUBA, František
The contamination of the food chain of wild boar by post-Chernobyl radioactive fallout is a continuing problem in the forest ecosystems of certain localities in the Czech Republic. This study/PhD thesis is therefore focused on the evaluation of the results of radioactive contamination by radiocaesium (137Cs) of meat of wild boar caught in the localities of Novohradské Mountains and Šumava National Park in the period from December 2012 to December 2019. The aim of the work was to evaluate the occurrence of radioactive load in wild board, identification of possible seasonal trends in measured values of 137Cs, as well as possible differences in selected localities, and to evaluate the presence of 137Cs in raw materials of animal origin, specifically from wild boar, as a possible source of contamination in the human food chain. During the monitored period from December 2012 to December 2019, 137Cs content was measured in 1607 samples of wild boar, of which 654 samples were from the Novohradské Mountains in the South Bohemian Region and 953 samples from the Šumava - South Bohemian and Plzeň Region. The threshold value of 600 Bq/kg of the total amount of caesium was exceeded in 763 samples out of the total number of 1607, which is 47.5%. The maximum value of 137Cs activity was 22,540 Bq/kg, the median value was 522,4 Bq/kg and the average value was 1368,2 Bq/kg. Statistically significant differences were found between localities Novohradské Mountains and Šumava National Park. Samples from Novohradské Mountains exceeded the threshold 600 Bq/kg in 238 out of a total of 654 samples (36,4 %) of caught wild boar. In samples from the Šumava National Park, samples exceeded the threshold in 525 out of a total of 953 samples (51,1 %). When assessing the seasonal effect of the measured values of 137Cs activity in caught wild boar, statistically significant differences were detected in the winter period (November - April), when 137Cs activity reached higher values. The average value in the winter was 1674,23 Bq/kg, the median value was 741,87 Bq/kg while in the summer period (May-October) the average value was 1022,69 Bq/kg and the median value was 376,51 Bq/kg. Differences in measured values are also visible when taking into account the seasonality. In the period from December to May (each monitored year) there was a noticeable increase in measured values in the localities of Novohradské Mountains, in contrast, in the locality of the Šumava National Park this seasonality is not reflected. In general, higher measured values of 137Cs activity were shown by samples from localities of closed forest ecosystems with no or minimal share of pastures and agricultural land.
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