||Increased Toxicity of Ammonia to Rainbow Trout 'Salmo gairdneri' Resulting from Reduced Concentrations of Dissolved Oxygen.
Thurston, Robert V. ;
Phillips, Glenn R. ;
Russo, Rosemarie C. ;
||Montana State Univ., Bozeman. Fisheries Bioassay Lab.;Environmental Research Lab.-Duluth, MN.
||EPA-R-800861 ;EPA-R-803950; EPA-600/J-81-587;
Salmo gairdneri ;
Water pollution effects(Animals)
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The median lethal concentration (LC50) of aqueous ammonia at reduced dissolved oxygen (D.O.) concentrations was tested in acute toxicity tests with rainbow trout (Salmo gairdneri) fingerlings. Fifteen 96-h flow-through tests were conducted over the D.O. range 2.6-8.6 mg/L, the former concentration being the lowest at which control fish survived. There was a positive linear correlation between LC50 (milligrams per liter un-ionized ammonia) and D.O. over the entire D.O. range tested; ammonia toxicity increased as D.O. decreased. Ammonia LC50 values were also computed for 12, 24, 48, and 72 h; the correlation with D.O. was greater the shorter the time period.