was there a toxic metal detected in that lake?
Yes,  high level of methylmercury
Great Salt Lake
During a survey in the mid-1990s, U.S. Geological Survey and U.S. Fish and Wildlife Service researchers discovered a high level of methylmercury in the Great Salt Lake with 25 nanograms per liter of water. 
what kind of fish are in the great salt lake in utah UNANSWERABLE is it a freshwater lake or a saltwater lake? Salt water lake what could be the reason for the salinity of this water body? Most of the salts dissolved in the lake and deposited in the desert flats, lake's waters are slightly enriched in potassium and depleted in calcium. where exactly is this water body found? Northern part of the U.S. state of Utah how deep is this water body? In 1963 it reached its lowest recorded size at 950 square miles (2,460 km²), but in 1988 the surface area was at the historic high of . what are some of the biotic components found in this lake? Brine shrimp,  brine flies, and several forms of algae what is the approximate size of the first species mentioned? UNANSWERABLE
wiki:5399427
Great Salt Lake [SEP] Elevated mercury levels
During a survey in the mid-1990s, U.S. Geological Survey and U.S. Fish and Wildlife Service researchers discovered a high level of methylmercury in the Great Salt Lake with 25 nanograms per liter of water. For comparison, a fish consumption advisory was issued at the Florida Everglades after water there was found to contain 1 nanogram per liter. The extremely high methylmercury concentrations have been only in the lake's anoxic deep brine layer (monimolimnion) below a depth of , but concentrations are also moderately high up in the water column where there is oxygen to support brine shrimp and brine flies.