Professors, students to collect soil samples to determine mud and sediment sources
The Midwest floods of 2008 and the resulting pollutants left in Cedar Rapids, Iowa, will be the focus of a year-long, $100,000 National Science Foundation (NSF) study by University of Iowa (UI) researchers in cooperation with the Linn County Board of Supervisors, beginning Aug. 26.Project principal investigators Keri Hornbuckle and Thanos Papanicolaou, professors of civil and environmental engineering and researchers at IIHR-Hydroscience and Engineering, said that they and about a dozen UI undergraduate and graduate students will begin collecting soil samples from lawns adjacent to roadways and grassy land within the flood zone of the city."We hope to determine the major sources of the mud and sediments that the floodwaters left behind," Hornbuckle said. "We will measure radionuclides, stable isotopes of nitrogen and carbon and persistent organic pollutants such as PCBs [polychlorinated biphenyls] and chlordanes in Cedar Rapids sediments to trace the suspension, transport and deposition of sediments within Cedar Rapids. Although much of the mud and muck has disappeared, we are confident that the chemicals needed for their research remain." She added that Linda Langston, chair of the Linn County Board of Supervisors, will be a key person in the overview of data collection sites.Researchers will be equipped with small shovels, sampling jars and bags, GPS units and clipboards. The goal is to collect about 400 soil samples from grassy areas of the city, with additional sampling conducted in the Cedar River and Cedar Lake via a boat through core sampling and bed-load sediment measurements. Used as a cooling lake for the Sixth Street Generating Station and having an average depth of less than 4 ft, Cedar Lake is especially important because it is contaminated with chlordanes and PCBs."The origin of the sediments that now cover the city of Cedar Rapids is the focus of this project," Hornbuckle said. Hornbuckle and Papanicolaou said that the project and its findings will be of interest to the city as well as their fellow engineers. The project will use state-of-the-art measurement techniques, and the strategy being tested can be used by other researchers to track sediments in similar floods.The UI researchers are scheduled to report their findings to the National Science Foundation by July 2009.