Pre-enrichment of radioactive cesium in muddy water separated into suspended and dissolved substances for trace analysis

Abstract A new in-situ pre-enrichment system was developed for trace analysis of radioactive Cs in environmental water such as rivers, ponds, and seas, where the radioactive Cs is separated into suspended substances (SS) and dissolved substances (DS). The SS component was collected as the enrichment slurry by cross-flow filtration, thereby compact systems were realized. The DS component was collected in a small cartridge filled with a non-woven fiber with immobilized adsorbent nanoparticles. The recovery rate was estimated at around 95%. The size distribution of the SS and the concentration of radioactive Cs after enrichment were the same as that of the raw water before enrichment. The condensed SS can be used for other evaluations such as ignition loss. From the field test at a pond in the Fukushima-area, the Cs concentration of the SS was found to be 4–5 times higher than that of the sediment in the same pond. The organic content estimated by ignition loss was also three times higher.