Ill 



WDr'» Conclunom and Recommendation* 



WDF'e general conclusions (Schroder and Fresh 1992) were that: 



(1) many potentially toxic chemicals were in the effluente; 



(2) Weyerhaeuser tended to have more detectable compounds than ITT; 



(3) all chemicals were typical of pulp mills; 



(4) all known chemical concentrations were below known danger levels for 

 aquatic organisms; and 



(5) none of the compounds could be directly linked to salmon survival. 



Schroder and Fresh (1992) recommended continuing to coded wire tag coho smolts 

 at least until the 1992 brood year; resuming hatchery fall Chinook tagging; 

 and investigation into the role of sediment contamination in the pollution 

 block. In the event that tagging does not indicate improved survival, they 

 recommended investigating the interaction of the intensity and location of 

 parasite infestation, particularly N&nophyetus , with effluent composition. 



Relative Iaportance of Effluents to rish Mortality 



Through painstaking research, the agencies ruled out virtually every other 

 hypothesis for Chehalis syBtem smolt mortality. Some of the substantiating 

 evidence follows. 



(1) Upper Chehalis coho smolt production is similar to production in other 

 western Washington rivers (Seiler 1987). 



(2) Northern squawfish (Ptychocheilus oregonensis) could only be consuming 

 about seven percent of hatchery smolts and less than one percent of wild 

 smolts in the Chehalis River (Schroder and Fresh 1992). 



(3) Upper ChehaliB waters do not have chronic or widespread toxicity 

 problems (Michaud 1989). 



(4) Neither the Aberdeen, Hoquiam, and CoBtnopolis sewage treatment plants 

 were impairing aquatic organisms (Schroder and Fresh 1992). 



(5) Physiological tests determined that coho smolts usually entered the 

 lower Chehalis as robust, stress-free fish (Schroder and Fresh 1992). 



Recent Claan-uo of Pulp Mill Effluent 



In 1990, both mills began substituting oxygen or other chemicals for chlorine 

 in the bleaching process, and took steps to prevent accidental spills of toxic 

 materials into the mill waste stream. Each mill also took unique steps to 

 further reduce effluent toxicity (Reif 1989a; Johnson et *1. 1990). 



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