Evaluation of two sediment tracers under simulated rainfall

A number of different tracing approaches have already been established, including the use of rare earth oxides or environmental radionuclides. However, since existing techniques face various limitations, the search for alternative procedures continues. Two alternative tracing approaches involve the use of organophilic clays and magnetic iron oxides. This study performed a combined test of these tracers to assess potential contrasts in their behaviour under a controlled rainfall simulation experiment. The experiment consisted of a simulated rainfall event of 55 mm.h(-1) applied to a bed shoulder system (2 x 1.14 m). The results highlighted differences between the tracers in terms of their enrichment in sediment and different soil aggregate classes. Comparison of the contribution of the different plot sections to the total sediment export using both tracers suggested that most of the sediment originated from the shoulders.