Mercury concentrations in muscle tissue from sportfish in Lake Mead, Nevada

Mercury Concentrations in Muscle Tissue from Sportfish in Lake Mead, Nevada by Joanna L. Kramer Dr. Shawn L. Gerstenberger, Committee Chair Professor, Department of Environmental and Occupational Health School of Community Health Sciences University of Nevada, Las Vegas Lake Mead is the largest reservoir by volume in the United States and provides fishing opportunities for numerous anglers. Considerable attention has been given to the bioaccumulation of methylmercury in fish tissues, however, no formal study utilizing approved USEPA methodology has been conducted to quantify the amount of mercury present in fish tissue from Lake Mead. The purpose of this study is to determine the concentrations of mercury present in the most commonly consumed fish from Lake Mead and to identify if any of the 4 major basins contain fish with elevated concentrations of mercury. Largemouth bass (n=49), striped bass (n=94), and channel catfish (n=78) were collected from selected sites in Boulder Basin, Overton Arm, Virgin Basin, and Gregg Basin of Lake Mead by gill netting or electrofishing. Muscle tissue was homogenized, digested, and analyzed for mercury in accordance with USEPA Method 245.6 which must be used to construct human health based fish consumption advisories. Mean mercury concentrations were (x ±SD) 0.089± 0.065 ppm, 0.154±0.127 ppm, and 0.098± 0.080 ppm in largemouth bass, striped bass, and channel catfish, respectively. An