tetrachlorophenol were deterrained in the present study in addition 

 to the toxicities of di- and tetrachlorocatechol. 



The mechanism by which chlorinated catechols cause toxicity 

 has not been reported, but a possible mode of action can be assumed 

 from knowledge of the toxic action of the structurally similar 

 compound, pentachlorophenol. Toxicity of pentachlorophenol results 

 from its interference with phosphorylation processes in the living 

 cell (White et al., 1959). This interference is termed "uncoupling 

 of oxidative phosphorylation" and occurs when a substance enters a 

 living cell and disrupts the flow of energy from ''energy yielding" 

 functions (e.g., oxidation of food) to "energy requiring" functions 

 such as cell maintenance and synthesis. Uncouplers are quick acting 

 toxicants and may cause death in a few minutes or hours at acutely 

 toxic concentrations. 



A symptom commonly associated with "uncoupling" is increased 

 respiration (oxygen consumption) which occurs because the metabolic 

 processes attempt to overcome a deficit in the flow of energy to 

 those functions requiring it. Since tetrachlorocatechol is somewhat 

 similar in chemical structure to pentachlorophenol, the possibility 

 exists that it too may be an "uncoupler", in which case respiration 

 rate of fish in contact with acute or subacute concentrations of 

 tetrachlorocatechol would be increased. In order to test this 

 possibility, respiration rates of young sockeye and pink salmon in 

 contact with di- and tetrachlorocatechol were compared with normal 

 respiration rates in water only. 



It has been assumed that chlorinated catechols may be present in 

 bleach waste. Since these v-iastcs are oxidized in biological systems 

 to reduce toxicity, it is logical to question whether chlorinated 

 catechols may resist this treatment and be discharged to the 

 receiving waters. Catechol can be oxidized during biological treatment 

 (Malaney, I960) , but there is no report of the oxidation of chlorinated 



