Comparison of Mercury in Water, Bottom Sediment, and Zooplankton in Two Front Range Reservoirs in Colorado, 2008-09

摘要

The purpose of this report is to compare mercury concentrations in water, bottom sediment, and zooplankton samples collected from two Front Range reservoirs in Colorado during 2008 and 2009 and to evaluate factors that may be contributing to bioaccumulation of mercury in fish. Additionally, this report presents results of a sediment-incubation experiment conducted in 2009 to evaluate the methylation potential of sediments in these two reservoirs. The two reservoirs, Brush Hollow and Pueblo Reservoirs, are located in the Arkansas River drainage within 20 miles of each other yet have very different fish-tissue mercury concentrations. Mercury concentrations in walleye, which is the top predator fish in each reservoir, are below analytical detection in tissue samples from Pueblo Reservoir but exceeded the fish-tissue criterion for the State of Colorado in some tissue samples from Brush Hollow Reservoir.