title: The use of an ordinary colour scanner to fingerprint sediment sources in the South African Karoo.
abstract: The widespread adoption of sediment fingerprinting methodologies for the purpose of catchment management has been restricted by the high cost of tracer analysis as well as the potential for significant uncertainties to be present in results. Sediment colour has shown potential to be an inexpensive tracer able to discriminate between sediment sources. However, at present colour has not been demonstrated to be conservative during sediment erosion and transport. Sediment particle size and organic matter have been shown to strongly affect sediment colour, introducing significant uncertainties associated with its use. This study aimed to assess the suitability of colour as a tracer when it is measured using a commercially available colour scanner. The use of hydrogen peroxide (H2O2) to decompose sediment-associated organic matter was assessed as a means of minimising uncertainty. The impact of particle size on the accurate use of colour signatures as a tracer was also assessed. It was concluded that colour performed comparably to mineral magnetic signatures and showed good potential for use as a tracer. The use of H2O2 pre-treatment and limitation of the analysis to either the <32 μm or the >32 μm fraction of the samples were indicated to be important methods to limit uncertainties associated with organic matter and particle size. The methods used were considerably more time and cost effective than the measurement of most conventional tracers.
authors.affiliation: Geography Department, Rhodes University, South Africa. Electronic address: s.pulley@ru.ac.za.
authors.forename: Simon
authors.initials: S
authors.lastname: Pulley
authors.affiliation: Geography Department, Rhodes University, South Africa.
authors.forename: Kate
authors.initials: K
authors.lastname: Rowntree
mesh_terms: D003116:Color; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry*; D006861:Hydrogen Peroxide; D010316:Particle Size; D013019:South Africa; D035501:Uncertainty
chemical_list: D006861:Hydrogen Peroxide
keywords: Colour; Inexpensive; Sediment fingerprinting; Sediment sources; Uncertainty