137Cs losses from a loamy surface water gleyed soil (Inceptisol); a laboratory simulation experiment

137Cs was applied with simulated rainfall to 0.25 m2 soil boxes at an intensity of 20 mm hr−1 for 30 minutes. Ten simulations were performed on six soil boxes at 2° and 4° slopes. Soil was compacted in one box to simulate the effects of tractor wheelings. The depth distribution of 137Cs was analysed in six soil cores. In addition, a 1 m long × 16 cm wide soil trough was placed under the simulator until a constant rate of overland flow was generated. 137Cs was added at four locations at increasing distance from the trough outflow. Overland flow, drainage water and suspended sediments were collected and analysed separately for 137Cs in all experiments. slopes, the highest proportion of the 137Cs input was lost by drainage. At 4° slopes, and with compaction, the greatest amount of 137Cs was eroded with sediment. Approximately 10% of the added 137Cs was lost from the compacted soil over the ten simulations. 137Cs retention in the upper 10 cm of the profile ranged from more than 95% (compacted soil) to less than 45% (uncompacted soils). Results from the trough experiment suggested that 137Cs could be preferentially adsorbed by sediments entrained in overland flow.