37 



consumption of pimkinseed simflsh after exposure to a concentration 



which was 25 per cent of the 96-hr TL (Cairns and Scheier, 1964). 



No effect on oxygen consuiaption v/as noted at a Jieldrin concentration 



which was 11 per cent of the 96-lir TL . The relative levels at 



m 



which sublethal effects of tetrachlorocatechol were obtained with 

 sockeye alevins in the present study are m the sane order of 

 magnitude as noted for Dieldrin and mdxcato that sorae sublethal 

 toxic effects may be readily noted at concentrations of 

 tetrachlorocatechol ranging from 10 to 30 per cent of the 96-hr TL . 



Respiration tests showed that young sockeye salmon v;ere 

 sensitive to tetrachlorocatechol over a v/ider range of concentrations 

 than were young pink salmon. The opposite result might have been 

 expected since, on the basis of acute toxicity, pink salmon were 

 less tolerant than sockeye. Indications are that although general 

 reactions of one species of Pacific salmon may bo applicable to the 

 other, specific results may not be. Therefore, proper consideration 

 must be given to the sensitivities of each species when considering 

 the effects of potential pollutants in specific locations. 



Biological Treatment and Chlorinated Phenolic 

 Compounds in Bleach VJaste 



Results have sho\m that tetrachlorocatechol was apparently 

 oxidized by biological treatment \dth activated sludge. It can 

 therefore be assumed that the less highly chlorinated catechols, 

 mono-, di- and trichlorocatcchol, would be oxidized as well, if 

 present in bleach waste, as this reasoning was shown valid for the 

 closely related chlorinated phenols (Ingols et al. , 1966). 

 Oxidation of tetrachlorophenol, if it exists m bleach waste, 

 would also be very likely. 



Toxicity reduction of ifBVJ to which 3 ppm tetrachlorocatechol 

 was added was slower than that of IffiW. This difference in rate of 

 toxicity reduction may have been caused by need for the biological 



