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Cesium-137 in forest fruits
VRBOVÁ, Anežka
Significant artificial radionuclides occurring in the environment include Cs-137 from nuclear weapons tests that took place in the atmosphere during the 1950s and 1960s, and nuclear power plant accidents, such as at Chernobyl block 4 and crash at Fukushima. This bachelor thesis compares the amounts of Cs-137 and K-40 in different types of forest fruits, such as blueberries, raspberries and blackberries. Certain sites in Šumava were selected for their collection, where there was significant radioactive fallout after the Chernobyl nuclear power plant accident in 1986. Using semiconductor gamma-ray spectrometers, the specific activity of Cs-137 and K-40 was measured. All samples were measured in the dry state (dry matter). Cs-137 measurement values ranged from 1,143 Bq.kg-1 to 500 Bq.kg-1. For K-40 measurements, the values ranged from 166 Bq.kg-1 to 1280 Bq.kg-1. Differing values in individual localities are the result of uneven rainfall when the radioactive cloud passed over our territory after the Chernobyl disaster. However, there are also differences between species of forest fruits, which exhibit different accumulation properties due to different root system depths and their surrounding soil properties. The measured values were compared to the established limits and radiation sources found in our environment. The values measured are not high and compared to other sources of radiation are negligible, which has little impact on our health.
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