Sediment-deposition rates and organic compounds in bottom sediment at four sites in Lake Mead, Nevada, May 1998

: In May 1998 the U.S. Geological Survey in cooperation with the University of Nevada Las Vegas investigated rates of sediment deposition and concentrations of selected synthetic organic compounds at four sites in Lake Mead. Sediment cores were extracted from two sites (one shallow and one deep) in Las Vegas Bay from one site in the Overton Arm, and from one site near the historic confluence of the Colorado and Virgin Rivers. The sediment cores were age-dated using cesium-137 and were analyzed for the presence of organochlorine compounds (pesticides and degradation products polychlorinated biphenyls dioxins and furans) and for semivolatile organic compounds (polycyclic aromatic hydrocarbons and phenols).