Environmental mobility of cesium-137

Abstract

During a 2-year study, erosion, soil losses of 53, 2·5 and 0·9 metric tons/ha were coupled with 137Cs losses of 43, 19 and 7 per cent, on 2·3 × 2·3 m bare soil, poor meadow and good meadow plots respectively. Runoff and erosion losses of 137Cs from vegetation-covered plots occurred primarily in the initial stages following the application, due to washoff from vegetation, at a rate approximately ten times greater than would be expected on the basis of soil loss alone. Evidence of 137Cs redistribution was determined by sampling and analysis techniques which facilitate a fair material balance. Uptake of 137Cs by new vegetation was only a small fraction of originally applied 137Cs. An empirical relationship between cesium loss and soil loss of the form: ψ = A(x/b) n , where Ψ = Cs loss, x = soil loss, b = a units constant, A = a coefficient and n = an exponent, fits the data well. These results indicate that movement of radionuclides by runoff and erosion may be quite important.