Comparative analysis of radioactive cesium wash-off from contaminated catchment areas after accidents at the Fukushima Dai-ichi and Chernobyl nuclear power plants

Resumo

The paper presents quantitative data on radiocesium wash-off (dissolved and particulate) from catchment areas after the accident at the Fukushima-1 nuclear power plant. The evaluations are conducted based on published data on radiocesium monitoring in streams in the accident zone and monitoring at standard USLE plots. The characteristics of radiocesium wash-off and its distribution coefficient in riverine waters and surface runoff are analyzed by comparing data obtained on the territories of the Fukushima and Chernobyl accidents within a few years after the accidents. The normalized radiocesium wash-off coefficients in solution for the Fukushima river catchment area are one to two orders of magnitude lower than the analogous values for the Chernobyl catchment area. The normalized wash-off coefficients of radiocesium on particulate matter in the Fukushima and Chernobyl catchment areas are comparable. However, at least twice higher mean annual precipitation and steeper slopes in the Fukushima catchment area result in a higher annual wash-off coefficient than that of the Chernobyl area. It is demonstrated that characteristics of radiocesium wash-off obtained at USLE plots can be utilized to evaluate the scales of natural catchment areas.