Lateral and temporal variations in Fukushima Dai-ichi NPP-derived Cs and Cs in marine sediments in/around the Sado Basin, Sea of Japan.

Lateral and temporal profiles for concentrations of Cs and Cs were examined in marine sediments obtained from coastal and offshore areas on the Sea of Japan-side of central Honshu. In 2013, concentrations declined sharply from an estuarine (30 Bq/kg-dry for Cs) to offshore areas. In the offshore Sado Basin, the concentration of short-lived Cs, which was not detected (<0.3 Bq/kg-dry) in 2010, was 1-15 Bq/kg-dry in 2011-2013. Discharged riverine materials affected by radiocesium derived from the Fukushima Dai-ichi Nuclear Power Plant have been delivered to this offshore basin. [ABSTRACT FROM AUTHOR]