Prediction of groundwater contamination with super(137)Cs and super(131)I from the Fukushima nuclear accident in the Kanto district

We measured the concentrations of super(131)I, super(134)Cs, and super(137)Cs released from the Fukushima nuclear accident in soil and rainwater samples collected March 30-31, 2011, in Ibaraki Prefecture, Kanto district, bordering Fukushima Prefecture to the south. Column experiments revealed that all super(131)I in rainwater samples was adsorbed onto an anion-exchange resin. However, 30% of super(131)I was not retained by the resin after it passed through a soil layer, suggesting that a portion of super(131)I became bound to organic matter from the soil. The super(137)Cs migration rate was estimated to be approximately 0.6 mm/y in the Kanto area, which indicates that contamination of groundwater by super(137)Cs is not likely to occur in rainwater infiltrating into the surface soil after the Fukushima accident.