Radioactive cesium flow in Rhus vernicifera

Abstract

"Urushi" syrup from Rhus vernicifera DC. was collected monthly from June to October 2011, to represent sieve tube exudates from trees, and the radioactivity of samples was measured. In the syrup, the cesium (Cs) concentration (134Cs and 137Cs) originating from the meltdown at the Tokyo Electric Power Company, Inc. (TEPCO) Nuclear Power Station in Fukushima peaked in July and decreased to a minimum in October, while the natural radioactive potassium-40 (40K) remained constant during the same period. On the basis of these results, we assumed that the radioactive Cs in the urushi syrup was directly translocated from the fallout adsorbed to tree bark rather than from contaminated soil. © 2012 Copyright Taylor and Francis Group, LLC.