Radionuclide Contents of Leafy Vegetables; Their Reduction by Cooking

Abstract

Decontamination ratios of ¹⁰³Ru ¹³⁴Cs, and ¹³⁷Cs were determined for leafy vegetable samples after they were cooked. Samples contaminated with radionuclides from the Soviet Chernobyl reactor accident were obtained in Akita City. The decontamination ratio of the ¹⁰³Ru content of washed spinach samples to that of similar unwashed samples was 0.83 ± 0.21. The ratio of the ¹⁰³Ru content of leafy vegetables and edible wild grass samples which were boiled in water to that of similar washed samples was, on the average, 0.72 ± 0.20. The overall decontamination ratio of ¹⁰³Ru in boiled leafy vegetable samples to unwashed vegetable samples was 0.52 ± 0.20. The decontamination ratios of ¹³⁴Cs and ¹³⁷Cs after washing were 0.65 ± 0.42 and 0.64 ± 0.17, respectively. The reduction ratios of ¹³⁴Cs and ¹³⁷Cs by boiling were 0.50 0.15 and 0.53 ± 0.13. The overall decontamination ratios were 0.33 ± 0.24 for 134 Cs and 0.34 ± 0.12 for ¹³⁷Cs. These results indicate that the decontamination ratio of 0.5 which is stipulated by the Nuclear Safety Commission, Japan, is a practical value.