15 



Thirty-one Jay Exposure 



During the 31-day exposure to chlorinated catechols, fish in 

 Group 1 progressed from the alevin into the fry stage, 14 days in 

 the former and 17 days in the latter. Fish m Group 2 v;ere at a 

 less advanced stage of development at the start of the bioassay and 

 spent 29 days as alevms and two as fry m contact with tetra- or 

 dichlorocatechol . 



Mortalities of sockeye alevins exposed to 0,6 ppm 

 tetrachlorocatechol were 79 and 76 per cent in Groups 1 and 2, 

 respectively, after nine days (TABlii U) , Fish remaining alive 

 after nine days m 0.6 ppm tetrachlorocatechol were severely 

 distressed, some being moribund, so this concentration was 

 discontinued in order to conserve reagent which was in short supply. 

 The bulk of the mortalities in both groups occurred primarily during 

 a IS-hv interval from the seventh to the ninth days of exposure. 

 No significant mortalities occurred at tetrachlorocatechol 

 concentrations of 0.2, 0,1 or 0.06 ppm. 



At 0.2 ppm dichlorocatechol (TABLL 4), no mortalities were 

 recorded among either group tested. Unfortunately, higher 

 concentrations of dichlorocatechol could not be tested vjithout 

 exhausting supplies required for other experiments. 



With the exception of fish exposed to 0.6 ppm tetrachlorocatechol, 

 all surviving alevins apparently progressea normally to the fry 

 stage and readily accepted food. 



Acute Toxicity of Chlorinatcci Phenols 



Thtt chlorinated phenols were found to be more toxic than the 

 respective catechols. The 96-hr TL 's of tetra- and dichlorophenol 

 were 0.4-8 and 1.7 ppm, respectively, for sockeye fry from Pitt Lake 

 incubation channel. That is, tetra- and dichlorophenol were about 

 1.8 and 1.6 times as toxic, respectively, as the corresponding 

 catechol. 



