Pollution of radiocesium and radiosilver in wharf roach (Ligia sp.) by the Fukushima Dai-ichi Nuclear Power Plant accident

Radionuclide concentrations in wharf roaches inhabiting coastal areas of Honshu, Japan, were investigated in October 2011 and June 2012. Relative high concentrations of 110mAg (2.1–127 Bq kg-wet−1), 134Cs (2.6–61 Bq kg-wet−1), and 137Cs (3.5–92 Bq kg-wet−1) were detected in specimens from the eastern Honshu areas. Significantly lower 137Cs concentrations (0.7–1.6 Bq kg-wet−1) were detected in specimens from western and northern Honshu. The decay-corrected 137Cs concentration was significantly inversely correlated with the distance from the Fukushima Dai-ichi Nuclear Power Plant. Thus, wharf roach may serve as a good bioindicator for monitoring radioactive contamination of its habitats.