Summary

Description

The Nevada Fish and Wildlife Office of the U.S. Fish and Wildlife Service, in cooperation with the U.S. Department of Interior National Irrigation Water Quality Program, investigated the aquatic toxicity of water in irrigation drains in the Newlands Project area near Fallon, Nevada in 1995. The purposes of this report were to: 1 investigate the degree of seasonal variability and its effects on the quality of irrigation drainage in the Newlands Project near Fallon, Nevada; 2 identify source areas of the Newlands Project where irrigation drainage contributes most to aquatic toxicity in Lahontan Valley; and 3 identify specific water quality parameters that contribute to toxicity of aquatic biota. Water samples were collected from a number of drains during March, May, and August 1995 in the Lahontan Valley for trace element residue analysis and toxicity testing. Samples collected in August 1995 were also analyzed for the presence of a variety of pesticides commonly used in the Lahontan Valley. Water samples were used in two types of bioassay tests. Constituent concentrations and bioassay test results were used to fulfill the above purposes.