Figure 1.
Sampling and fractionation of bamboo shoots.
(a) Map of Japan showing the location of the twelve sampling sites and the Fukushima Daiichi nuclear power plant. (b) Schematic workflow of the bamboo shoot fractionation. The basal part was cut off (black down-arrow), and about 10–15 culm sheaths were stripped (black right-arrow). The culm sheaths were cut into the upper and lower parts. The stripped bamboo shoot was separated into the apical culm sheath and the upper and lower edible parts (white arrows).
Figure 2.
Radiocesium contamination in bamboo shoots of Phyllostachys pubescens.
(a, b) Scatter plots of the radioactive concentrations of radiocesium, 134Cs (a) and 137Cs (b), of the surface soils and the upper edible part. (c, d) The radioactive concentrations of radiocesium, 134Cs (c) and 137Cs (d), in each part of the bamboo shoots collected in Tsukubamirai in Ibaraki Prefecture in April 2012. Error bars indicate measurement deviation.
Table 1.
List of sampling bamboo shoots and their Cs-134 and -137 concentrations in the upper edible part.
Figure 3.
Distribution of radiocesium in bamboo shoots sampled in April and May 2012.
(a, b) The radioactive concentrations of radiocesium, 134Cs (a) and 137Cs (b), in each part of the bamboo shoots collected in Date, Fukushima Prefecture (41 km from Fukushima Daiichi). (c, d) The radioactive concentrations of radiocesium, 134Cs (c) and 137Cs (d), in each part of the bamboo shoots collected in Ichikawa (215 km from Fukushima Daiichi) and Kashiwa (195 km from Fukushima Daiichi) in Chiba Prefecture. NS indicates not sampled. (e, f) The radioactive concentrations of radiocesium, 134Cs (e) and 137Cs (f), in each part of the bamboo shoots collected in Aizuwakamatsu in Fukushima Prefecture (102 km from Fukushima Daiichi) and Annaka in Gunma Prefecture (225 km from Fukushima Daiichi). Error bars indicate measurement deviation.
Figure 4.
Comparison of radiocesium and potassium in each part of the bamboo shoots of Phyllostachys pubescens.
(a, b) Scatter plots of the radioactive concentrations of radiocesium, 134Cs (a) and 137Cs (b), and the potassium concentrations. UEP, LEP, BP, ACS, UCS, LCS indicate the upper edible part, lower edible part, basal part, apical culm sheath, upper culm sheath and lower culm sheath, respectively. (c, d) The mean ratio of the radioactive concentrations of radiocesium, 134Cs (c) and 137Cs (d), to the potassium concentrations. Error bars show the standard deviation for three separate bamboo shoots in Tsukubamirai as shown in (a, b). Significance was determined using Welch's two-sample test. p-value *<0.01, **<0.003, ***<0.001.
Figure 5.
Radiocesium contamination in bamboo shoots of Phyllostachys pubescens with an outcrop length of 3.5 m.
(a) The separated tall bamboo shoot collected in Kashiwa in Chiba Prefecture (195 km from Fukushima Daiichi). The stripped bamboo shoots were cut at 30 cm intervals from the tip, separating the upper edible part, and the middle parts 1, 2 and 3. Scale bar indicates 30 cm. (b, c). The radioactive concentrations of radiocesium, 134Cs (b) and 137Cs (c), in each part of the bamboo shoots shown in (a). Error bars show one standard deviation.
Figure 6.
Relationship between outcrop lengths and the radiocesium concentrations in bamboo shoots of Phyllostachys bambusoides Sieb. Et Zucc.
(a) The collected Phyllostachys bambusoides bamboo shoots. Scale bar indicates 10 cm. (b) The scatter plot of the radioactive concentrations of radiocesium in tip parts and the outcrop length. (c, d) The radioactive concentrations of radiocesium, 134Cs (c) and 137Cs (d), in each part of the bamboo shoots shown in (a). Error bars show measurement deviation.