Survey of Radioactive Cesium and Potassium Intake from Food Using Duplicate Diet (Fiscal Years 2011–2014)

Abstract

Dietary intake of radioactive substances (¹³⁴Cs, ¹³⁷Cs, ⁴⁰K) from food in fiscal 2011–-2014 was surveyed using the duplicate diet method. 1,612 diet samples were collected from general households of 18 prefectures. ¹³⁴Cs and ¹³⁷Cs were detected in samples from Fukushima Prefecture, Miyagi Prefecture and Tokyo Prefecture. ¹³⁴Cs and ¹³⁷Cs were detected in 11 samples in fiscal 2011, 12 samples in fiscal 2012, and 7 samples in fiscal 2013, but none was detected in fiscal 2014. The largest radioactivity in a sample was 12 Bq/kg in Fukushima Prefecture in fiscal 2011. The detected levels gradually decreased and were less than 1.0 Bq/kg in fiscal 2014. The maximum estimated dose of radioactive cecium was 0.14 mSv/year in fiscal 2011. Radioactive potassium was detected in every meal, and showed little change through the four years (median around 30 Bq/kg).