Repeatability and reproducibility of measurements of low dissolved radiocesium concentrations in freshwater using different pre-concentration methods

Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; Kubota, Tomijiro*; Maehara, Yuji*; Maeyama, Takeshi*; Okizawa, Yusuke*; Ota, Hiroaki*; Otosaka, Shigeyoshi  ; Sakaguchi, Aya*; Tagomori, Hisaya; Taniguchi, Keisuke*; Tomita, Masatoshi*; Tsukada, Hirofumi*; Hayashi, Seiji*; Lee, S*; Miyazu, Susumu*; Shin, M.*; Nakanishi, Takahiro   ; Nishikiori, Tatsuhiro*; Onda, Yuichi*; Shinano, Takuro*; Tsuji, Hideki*

We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the Cs results were within 2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.