Effects of ionizing radiation on the boreal forest: Canada's FIG experiment, with implications for radionuclides

Autor: S.C. Sheppard, B.D. Amiro
Rok vydání: 1994
Předmět:
Zdroj: Science of The Total Environment. 157:371-382
ISSN: 0048-9697
DOI: 10.1016/0048-9697(94)90600-9
Popis: The Field-Irradiator Gamma (FIG) experiment chronically irradiated a section of the Canadian boreal forest over a period of 14 years. Forest trees were affected at dose rates > 0.1 gGy·h −1 , but a herbaceous plant community thrived at dose rates up to 65 mGy·h −1 . Irradiation resulted in the establishment of four zones of vegetation: a herbaceous community, a shrub community, a narrow zone of dying trees, and a zone with no apparent impacts. Concentrations of 14 C, 99 Tc, 129 I, 137 Cs and 226 Ra that could cause a dose rate of 0.1 mGy·h −1 within vegetation were calculated. Chemical toxic effects on plants would be caused by 99 Tc and 129 I before radiological effects are predicted to occur. The calculated 226 Ra concentration is about a factor of 10 greater than that measured at some natural sites. Sufficiently high concentrations of 14 C and 137 Cs to cause an impact are unlikely unless a site is severely contaminated.
Databáze: OpenAIRE