Caesium-137 as a Soil Erosion Tracer: a Review

This paper describes a method of soil erosion and soil movement measurements using 137Cs as a tracer. This technique has been used successfully employed for more than 30 years. Caesium-137 is a valuable tracer to study soil erosion. Its chemical and biological movement in soil is limited. Practically all redeposition of caesium-137 in soil after fallout occurs with soil particles due to strong fixation of caesium onto soil particles. This technique overcomes many problems of the traditional techniques to study soil erosion. First of all, this technique gives quantitative results of soil erosion and deposition for the medium-term (about 40 years). Moreover, these results are possible to obtain in a relatively short time compared to the traditional methods. The 137Cs method to obtain quantitative value of soil erosion and deposition requires the availability of undisturbed sites to obtain the reference value of 137Cs fallout for the study area and a numerical relationship. Currently, there are many calibration relationships available and the calculation of the soil erosion from 137Cs activity data strongly depends on the chosen relationship and the parameters that were used for a particular model.