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Siletz River nutrients: Effects of biosolids application
Citation:
SIGLEO, A. C. AND W. E. FRICK. Siletz River nutrients: Effects of biosolids application. Presented at Pacific Estuarine Research Society Meeting, Newport, OR, February 28 - March 01, 2008.
Impact/Purpose:
Stream water nutrients were measured in the Siletz River, Oregon, with the goal of comparing dissolved nutrient concentrations, primarily the nitrogenous nutrients nitrate and ammonium, with previously collected data for the Yaquina and Alsea Rivers for the nutrient criteria program.
Description:
Stream water nutrients were measured in the Siletz River, Oregon, with the goal of comparing dissolved nutrient concentrations, primarily the nitrogenous nutrients nitrate and ammonium, with previously collected data for the Yaquina and Alsea Rivers for the nutrient criteria program. An additional concern on the Siletz River was the application of biosolids on adjacent fields from several sewage treatment plants. For that reason, a primary goal of the monitoring was to ascertain effects of biosolids application on the river water chemistry. Stream chemistry down-stream of the biosolids application was monitored hourly during late fall through the first winter storms using a YSI 6920 continuous monitor for nitrate, ammonium, temperature, pH and conductivity. During the first storm of the Fall season on October 19-20, 2007, dissolved nitrate concentrations increased by a factor of 3 and then decreased slightly for the remainder of the month. Ammonium concentrations increased by approximately 10% during the October 19-20 storm. During the major flood (> 20,000 cfs) of December 3, 2007, the concentrations of neither nitrate nor ammonium increased appreciably, although conductivity and pH decreased sharply as expected. The results suggest that biosolids application may increase the nitrogen components slightly during the first storm but does not strongly affect long-term river chemistry.