the well water control was 40 percent. Mortality was 10 

 percent or less in all of the river water/effluent dilutions. 

 However, reproduction of the daphnids in the 4.0 percent 

 effluent was noticeably less. Only 3.4 offspring were 

 produced per female compared to 10.6 in the control. 



An additional seven-day Ceriodaphnia test was also 

 conducted using the Clark Fork River water from nine loca- 

 tions--three above and six below Champion's discharge. There 

 were no statistical differences between stations with respect 

 to survival (all greater than 90 -percent). The only differ- 

 ence in reproduction among the stations was at Huson (below 

 Champion) where the number of offspring produced per female 

 was significantly greater than at all other stations. 



FUTURE ACTIVITIES r A report outlining the results of the 

 above studies will be prepared in the autumn of 1985. 



The EPA suggests that additional trout studies should be 

 conducted using only river water for dilution. A greater 

 number of test fish per dilution could, therefore, be 

 measured giving better detection of subtle effects on growth. 



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