Hydrogen peroxide treatment effects on the particle size distribution of alluvial and marsh sediments

Pretreatment of sediment with hydrogen peroxide to remove organic constituents and aid deflocculation is a common component of particle size analyses of terrestrial and marine sediments. This study quantitatively determined the effect of a range of treatment levels on particle size distribution among four sediment types representing a range of mineral/organic particle size distributions, organic content and particle characterisation (charcoal or detrital plant material). The hypothesis was that complete removal of organic particles would lead to improved repeatability of results for a given sample and treatment level. Repeatability was assessed with a coefficient of variance calculation and a comparison of particle size distribution patterns within and across treatments. The effect of treatment levels on commonly used distribution descriptors (e.g. texture ratios and measures of central tendency) were then examined for each sample. Samples characterised primarily by detrital material responded most readily to treatment, whereas charcoal-dominated samples required higher levels of treatment to achieve increased repeatability and disappearance of large organic particles. Certain distribution descriptors, such as modal analysis, were found to be more resilient to organic particle presence, although amplitude of the organic distribution and the degree of overlap with the inorganic signal in some cases obscured even this metric. Thus, final treatment recommendations are based on sample characteristics and the types of distribution descriptors used in a study.