US Fish & Wildlife Service


Date of this Version



Published in Contaminant Report Number: R6/704C/92, 1-27, (1992)


The U.S. Fish and Wildlife Service conducted a monitoring study in 1989,1990
and 1991 to determine if trace elements occur at levels that may affect the Wyoming toad (Bufo hemiophrys baxteri), a federally-listed endangered species. The study will provide information to help the Wyoming Toad Recovery Team to select reintroduction sites and in habitat acquisition efforts. Biologists collected water, sediment, aquatic invertebrates, algae and emergent insects from Mortenson Lake, historically occupied areas and proposed reintroduction sites. No major problems are apparent with trace elements in water, sediment and biota from sites providing existing or potential habitat for the Wyoming toad. Two algae samples from Lake Gellat had elevated cadmium concentrations of 1.19 and 2.19 µg/g dry weight; however, the source of cadmium is unknown as cadmium concentrations- in water and sediment were below detection limits. Additional analyses of algae from Lake Gelatt should be performed to verify cadmium concentrations.