The Role of Fluvial Sediments in Modifying Phosphorus in a Stream Environment.

The Illinois River Watershed is a source of a large amount of research concerning the fate and transport of phosphorus (P) from the landscape to surface waters. This is largely due to the regions rapid urban population growth and predominance in poultry production paired with a large surface network of streams and rivers. Five streams were selected consisting of 2 predominately agriculture, 2 predominately forest, and 1 predominately urban sub-basins. Within the stream, multiple locations of a reach were sampled for <20 mm sediment. The sediment was immediately brought back to a simulated stream environment (fluvarium). A sub-sample was set aside and P sorption-desorption properties determined using the Langmuir isotherm approach. The fluvarium experiment consisted of three phases (1) an initial equilibrium phase, (2) a poultry litter spiked P phase, and (3) a final flushing phase. Each phase consisted of monitoring flow in the fluvarium for 48 hours, with water samples taken at regular intervals to measure changes in P concentration with time of flow. Preliminary data showed that P uptake by sediments during flow increased in the order agricultural, urban, and forest, and those sediments from agricultural areas could support the highest concentration of P in stream water.