STUDY NUMBER : 6.5 



ORGANIZATION ; Environmental Protection Agency (EPA) 



TITLE OF STUDY ; Toxicity Tests and Algal Assays of Missoula 

 Wastewater Treatment Plant (WWTP) 



CONTACT ( S ) ; Dick Montgomery, Environmental Protection Agency- 



449-5486 



Loren Bahls, Montana Department of Health and 

 Environmental Sciences, Water Quality Bureau- 

 444-2406 



OBJECTIVES ; 1) Evaluate the potential toxicity of ammonia and 

 chlorine in the Missoula WWTP effluent to aquatic organisms and 

 determine if other potentially toxic substances are present in 

 the discharge, 2) evaluate the algal growth potential of nutrients 

 discharged to the Clark Fork River. 



DURATION ; 1987 



CURRENT STATUS ; The Missoula WWTP discharge permit is scheduled 

 for renewal in September, 1987. Past operation problems at the 

 plant led to plant modification and new construction designed 

 to improve effluent quality. The toxicity and algal assay tests 

 are designed to evaluate the quality of the effluent and its 

 potential impact on the Clark Fork River. The data resulting 

 from the tests will be used along with data developed by the 

 Montana Water Quality Bureau to establish discharge permit lim- 

 itations. 



As a supplement to the tests with the waste water treatment 

 plant, toxicity tests will be conducted with Ceriodaphnia to 

 evaluate potential heavy metals toxicity associated with spring 

 runoff induced increases in heavy metals to the Clark Fork River. 

 Water Scimples collected at selected stations from Deer Lodge 

 to Missoula will be collected and tested over a seven day period. 



PUBLICATIONS AND REPORTS ; 



Preliminary planning documents only. 



49. 



