Assessment of Dose Rates to Non-human Biota of Terrestrial Environment around Kaiga Generating Station, Kaiga

In this study, the radiological impact of naturally occurring radionuclides ( 238 U and 232 Th) and fallout radionuclide ( 137 Cs) in the soil around the Kaiga Generating Station (KGS), Kaiga, on the terrestrial non-human biota was investigated. Through the analysis of 113 soil samples collected from 2015 to 2021, the study determined mean activity concentrations of 2.9 ± 1.4, 19.6 ± 5.2, and 24.1 ± 4.3 Bq kg −1 d.w. for 137 Cs, 238 U, and 232 Th, respectively, in surface soil samples. Utilizing the ERICA assessment tool ( v 2.0) and employing the Tier-2 approach, the study estimated radiological doses to reference organisms in the terrestrial ecosystem around Kaiga. Lichens and bryophytes exhibited the highest activity concentrations for 137 Cs, 238 U, and 232 Th, while annelids showed the lowest activity for 137 Cs, and for 238 U and 232 Th, amphibians exhibited the minimum activity. The total dose rates (internal + external) ranged from 1.9E−03 to 6.7E−01 µGy h −1 . Despite the highest dose rate of 6.7E−01 µGy h −1 observed in lichen and bryophytes, all assessed dose rates remained below the ERICA screening level of 10 µGy h −1 . Risk quotient values for all reference organisms were less than 1 (RQ