Tracer properties of eroded sediment and source material

This paper examines the conservativeness of tracers through the sediment generation process. This is done by comparing a selection of tracer properties of sediment eroded from large plots by simulated rainfall, with the corresponding properties of the source materials within the plots. Sediment was generated using three simulated rainfall events for each of rive selected erosion source types in the Tarago catchment, Victoria, Australia. As there were particle size and organic content differences between the source material and the generated sediment, the measured tracer properties of the source material were corrected for these differences. The possible role of analytical errors in this investigation was also addressed. The gechemical property, concentration of Fe2O3, was not conservative for any of the process sources investigated. Concentration of Al2O3, was not conservative for three of the four process sources investigated, and the sum of molecular proportions of CaO**, Na2O, K2O and Al2O3 was not conservative for two of the four process sources investigated. Mineral magnetic properties, IRM850 and X were also found to be not conservative, although this may be the result of the complex relationship between particle size and mineral magnetic properties not being adequately accommodated in this analysis. The radionuclide tracers, Cs-137 and Pb-210(ex), were found to be conservative through the sediment generation process. Copyright (C) 2002 John Wiley Sons, Ltd.