increased concentrations exceeded calculated chronic and 

 acute levels of copper that would protect aquatic life. 

 However, the fluctuations in copper and zinc were neither 

 high enough nor long enough in duration to produce signifi- 

 cant mortalities during the test period. 



FUTURE ACTIVITIES ; In order to accurately measure the 

 success of reclamation and restoration activities planned for 

 the upper river, there is a need to assess the toxicity of 

 the upper Clark Fork River ' s waters to trout and other 

 sensitive aquatic organisms during "normal" runoff condi- 

 tions. Hopefully, the bioassays conducted at Deer Lodge in 

 1985 will be repeated, either by the EPA or other research- 

 ers, at a time when critical water quality conditions are 

 present in the river. 



49 



