A method for quantitative characterisation of the radiocaesium availability
to plants in forest ecosystems has been developed. For this purpose an exp
ression has been proposed to calculate the radiocaesium availability factor
in soils, which is a combination of key soil characteristics: radiocaesium
exchangeability, exchangeable calcium in soil and effective selectivity co
efficient. The experimental dependencies of the radiocaesium soil to plant
concentration factors for fern and bilberry, on the availability factor cal
culated by the above equation were satisfactory described by linear functio
n. The advantage of this method to characterise bioavailability of radiocae
sium and to estimate site-specific values of concentration factor is that t
he necessary soil characteristics may be taken from the reference literatur
e, evaluated by experts or determined with a simple experimental procedure.
The method can be used in development of a radioecological Geographic Info
rmation Systems.