The role of vegetation in the regulation of fluxes of technogenic radionuclides at different stages after radioactive fallout

Abstract

In the remote period after the radioactive fallout in the Chernobyl accident, the biological cycle of 137Cs in pine forests of the northern forest-steppe zone and in those of Bryanskoe Polesye become essentially different. In the cleaner northern zone with dark-gray forest soil, the 137Cs flux to the soil with litterfall exceeds its influx to the vegetation by a factor of 5; i.e., the 137Cs cycle differs from that of stable K, the descending flux being still dominant. In the more contaminated Bryanskoe Polesye zone with podzolic illuvial-iron sandy soil, the annual 137Cs influx to above-ground vegetation via root uptake exceeds its return to the soil with litterfall, i.e., the 137Cs cycle approaches the biological cycle of stable K.