Method for monitoring radioactive cesium concentration in water using cesium adsorption disk and GM survey meter

Nagano, Tetsushi  ; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika  ; Yasuda, Kenichiro   ; Yoshida, Zenko; Yamaguchi, Hiroaki*

An on-site monitoring method for radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to rapidly and easily ascertain whether the water quality meets standards on radiological contaminants in water. In this method, both dissolved and suspended forms of radioactive cesium are collected on the cesium adsorption disk by means of filtration of a water sample. Beta counting rate of the disk is converted into radioactivity using a conservative calibration factor obtained here. The present on-site method was applied to monitoring of decontaminated water of an outdoor school swimming pool in Date city after Fukushima Dai-ichi Nuclear Power Plant accident.