Fleck, Jacob A, Alpers, Charles N, Marvin-DiPasquale, Mark, Hothem, Roger L, Wright, Scott A, Ellett, Kevin, Beaulieu, Elizabeth, Agee, Jennifer L, Kakouros, Evangelos, Kieu, Le H, Eberl, Dennis D, Blum, Alex E, and May, Jason T, 2011, The effects of sediment and mercury mobilization in the South Yuba River and Humbug Creek Confluence Area, Nevada County, California: Concentrations, speciation, and environmental fate-Part 1: Field characterization: U.S. Geological Survey.