Transfer of ¹³⁷Cs and ⁹⁰Sr from finnish soils to cereal grains

STUK, Radiation and Nuclear Safety Authority, Research and Environmental Surveillance, P.O. Box 14, 00881 Helsinki, Finland

Abstract

The transfer of ¹³⁷Cs and ⁹⁰Sr from soil to cereal grains in various regions in Finland was studied in 1994-1997. The samples of cereal grains were collected from private farms and combined to represent different soil types and regions in Finland. Altogether 318 composite regional samples of rye, wheat, oats and barley were analysed for ¹³⁷Cs, and 45 for ⁹⁰Sr. The aggregated transfer factors from the mean regional ¹³⁷Cs deposition (kBq m^-2) to cereal grains were calculated. The soils were classified in three main types: organic, sand and silt, and clay soils. The mean transfer factors (m² kg^-1 (dw)*10^-3) of ¹³⁷Cs for cereal grains were highest in organic soils ranging from 0.013 to 0.12, lowest in clay soils, ranging from 0.015 to 0.061, and decreased in the order : oats > rye > barley on wheat. The concentrations of ⁹⁰Sr were higher in the cereal grains from sand and silt soils than from the clay and organic soils. The regional ¹³⁷Cs transfer factors from soil to cereal grains found in this study were compared with data for the nuclear weapons fallout period and for a few post-Chernobyl years.