The use of 137Cs as a tracer in an erosion study in south limburg (the Netherlands) and the influence of chernobyl fallout

Abstract The 137 Cs radioactivity of soils was used as a tracer of soil erosion in a catchment in the Netherlands: 143 samples were analysed to map the 137 Cs redistribution using geostatistical interpolation methods. Caesium‐137 activities on grassland are significantly higher than on arable land. Also, 137 Cs activities on waning slopes are higher and activities on steep slopes are lower. The soil erosion estimates, derived from the 137 Cs data, are used to validate the USLE erosion model. The recent Chernobyl nuclear accident also contributed to the 137 Cs activity. However, the Chernobyl input of 137 Cs, with a constant ratio of 1.765:1 to 134 Cs, cannot be used as a tracer of soil erosion. Because of the rapid decay of 134 Cs, we will not be possible to separate the sources of 137 Cs in the near future in areas significantly influenced by Chernobyl fallout and in these areas 137 Cs can no longer be used as a soil erosion tracer.