Distributions of contaminant concentration and particle size in fluvial sediment

The pipet procedure for particle size distribution of fluvial sediment was evaluated to determine if it can also be used as part of an approach for measuring concentration of contaminants on specific particle size fractions (e.g., clay, fine silt, coarse silt, and sand). Actual distributions of particle size and a contaminant (137Cs) were represented by the results of a settling column procedure. These results were compared with results from the pipet procedure. Particle size distribution results were similar for both procedures. To calculate the distribution of contaminant concentration on particle size fractions, two different approaches for analyzing information from the pipet procedure were used. Results from one of these pipet-based analyses compared very well with the distribution of contaminant concentrations measured with the settling column procedure; the other analysis based on the pipet data did not provide good results. The new procedure is especially useful for contaminated sediment applications.