Contamination of Slovak Bilberry (Vaccinium Myrtillus L.) with Radiocaesium ¹³⁷Cs in Selected Slovak Locations

The aim of this study was to determine the activity of post-Chernobyl ¹³⁷Cs in Slovak bilberry (Vaccinium myrtillus L.) from selected locations of Slovakia depending upon: the season, location and the soil-plant transfer factor (TF). The ¹³⁷Cs activity was determined in samples of forest soil and bilberry bushes (stems, leaves and fruits) growing on the soil in three locations: Arboretum Mlyňany (1), Hodruša-Hámre (2) and Javorníky (3). Altogether we collected 35 samples; namely 15 samples from Arboretum Mlyňany, 10 samples from Hodruša-Hámre and 10 from Javorníky. The samples of soil were examined also for the activity of ⁴⁰K. The samples were collected in the spring, summer and autumn in the years 2019 and 2020 and were analysed by a gamma-ray spectrometry method. The highest levels of ¹³⁷Cs activity concentrations were determined in Hodruša-Hámre in September where they reached 161 ± 13 Bq.kg⁻¹ in the soil, 3.95 ± 1.07 Bq.kg⁻¹ in the stems and 14.7 ± 4.26 Bq.kg⁻¹ in the leaves. The lowest levels were determined in the Arboretum Mlyňany in October where the ¹³⁷Cs activity in the soil reached 13.1 ± 1 15 Bq.kg⁻¹, while in the stems, leaves and fruits it was lower than the minimum detectable level. In the latter location, we also determined the highest activity of ⁴⁰K, the radioactive isotope physiologically and metabolically similar to ¹³⁷Cs. The mass activity of ¹³⁷Cs in all samples of bilberries were lower than the minimum detectable activity (MDA). The comparison of the results obtained in this study with the limit for total mass activity of radiocaesium (¹³⁴Cs + ¹³⁷Cs) in the food (600 Bq.kg⁻¹) allowed us to conclude that the fruits, stems and leaves of Slovak bil-berries present neither health nor environmental risk.