Home > Science Themes > Transport of Contaminants

Transport of Chemical and Biological Contaminants

What are the processes involved in movement of contaminants within the basin and into the Great Salt Lake?

Lake sediment cores will allow comparison of prehistory to history, and contrasting of tributary watersheds in terms of pollen, other ecological markers, sediment flux, and contaminant flux. Complementary monitoring of fluxes of dissolved and suspended constituents in tributaries to the Great Salt Lake and the lake itself provides the opportunity to relate present flux to historic accumulation within the lakes. These comparisons will also provide a basis for evaluation of biogeochemical processes controlling the fate of dissolved and suspended constituents within the watershed, and the consequences of these processes to ecological systems.

Many specific issues can be examined within this context. For example, methyl Hg (biotoxic form of Hg) is quite elevated in the Great Salt Lake, especially in a deep brine layer that covers 50% of the south basin of the lake (David L. Naftz, USGS, personal communication). These elevated concentrations raise ecological concerns for the wetlands surrounding the GSL, which are of hemispheric significance to migratory waterfowl. Since Hg-methylation is mediated by sulfate reducing bacteria, it is likely that the rate of methyl-Hg production is controlled by lake level fluctuations via exposure and re-oxidation of sulfides. As another example, contaminant introduction to the Great Salt Lake may also result from ostensibly beneficial processes, for example, the Jordan Valley Water Conservancy District is presently considering treating impaired groundwater in the Salt Lake Valley, an action that could postpone importation of Bear River water and associated ecological consequences to that watershed. However, treatment of impaired water by reverse osmosis (RO) yields elevated Se and other heavy metals in the RO concentrate. The consequences of release of the RO concentrate to the wetlands surrounding the lake are as yet uncharacterized (see www.deq.utah.gov/issues/nrd/).

Pages:  1 | 2 | 3 | 4 | 5 | 6 | 7 | 8