Radiocaesium contamination of bamboo shoots in Fukushima and surrounding regions after the Fukushima nuclear accident

Radiocaesium contamination of bamboo shoots was characterised using food monitoring data from 2011 to 2015 in Fukushima and surrounding prefectures in Japan. Though 134Cs + 137Cs activity concentration data on bamboo shoots exhibited a large variability in each prefecture and year, annual means of the activity concentrations gradually decreased with time. Until 2012 or 2013, some activity concentration data in each prefecture exceeded the regulatory limits for food in Japan, with the highest measurement of 3 100 Bq kg−1 fresh weight, and thereafter almost no data exceeded the limit. This activity concentration decrease was slower than that in farmed foods.