Radionuclides in imported foods consumed in Hokkaido were examined by germanium (Ge) gamma-ray spectrometer system.
The values of radioactive cesium (¹³⁷Cs+¹³⁴Cs) concentration of 480 samples collected during 1989-1999 were lower than the temporary limit (370Bq/kg) . These values of 441 samples (92%) were lower than 1 Bq/kg. The maximum values of ¹³⁷Cs and ¹³⁴Cs were 62.4Bq/kg, 3.8Bq/kg in black tea imported from China.
From the relation between concentration of ¹³⁷Cs and cesium unit, the contribution from Chernobyl reactor accident was estimated qualitatively on 24 samples with higher values than 0.40Bq/g-K. Based on the concentration of ¹³⁴Cs and ¹³⁷Cs detected in 16 samples, the contribution of ¹³⁷Cs from this accident were calculated.