Abstract
Field horsetail(Equisetum arvense) is a kind of fern, and the fertile shoots are eaten as vegetables in Japan in the spring. Since fern species tend to concentrate radiocaesium from soil, concentrations and distribution patterns of radiocaesium in the fertile shoots are of interest. In this study, distribution and food processing results were compared using samples collected in 2011(n＝1) and 2012(n＝3);the sample collected in 2011 received direct deposition from the Fukushima Daiichi Nuclear Power Plant accident while those collected in 2012 included radiocaesium mainly taken up from soil. About 200−300 shoots were collected at each sampling time. The 137Cs concentration in samples collected in 2012 decreased by 100−200 times compared to that in 2011. The radiocaesium distribution patterns in strobili, leaves and stems of 2012 samples were almost the same as those of 2011;however, the patterns were different from those of potassium. The radiocaesium removal percentage by food processing(washing＋boiling for 2.5min) was 70% in 2011, while that for 2012 samples was 32−72%;the effect of direct deposition and root uptake was not clear.
