personal conimunicution) that chlorination of guaiacyl propane units 

 may result in formation of di- and tetrachlorocatcchol, A pictorial 

 representation of the three compounds is presented below. The latter 

 two compoimds are broadly classified as chlorinated aromatic compounds 

 and are in a category called polyhydric phenols or phenolic compounds, 

 OK OH ^^ 



OCHo 



C-C-C 01 



guaiacyl propane unit dichlorocatechol tetrachlorocatechol 



The toxicity of chlorinated catechols to fish has not been 

 reported, but an indication of relative toxic strength to be expected 

 can be deduced from comparisons with compounds of similar chemical 

 structure. The chlorinated phenols, of which pentachlorophenol is 

 the most widely known fish toxicant, are structurally similar to 

 chlorinated catechols, as comparison of the following diagram with 

 the previous one indicates. 



OH 



Cl>~^=::^ 



dichlorophcnol 



CI 



CI 



CI 



CI 



CI 



pentachlorophenol 



According to Sexton (1953), toxicity of phenolic compounds to 

 bacteria depends upon the number of chlorine and hydroxyl groups on 

 the molecule. He explained that toxicity increased as chlorine was 

 added to a phenolic molecule, but that polyhydric phenols (such as 

 catechol) were less toxic to bacteria than was phenol itself. It can 

 be deduced from Sexton's generalizations that dichlorocatechol would 

 be less toxic to fish than tetrachlorocatechol, ana that the chlorinated 

 catechols would be less toxic than the corresponding chlorinated phenol. 

 Therefore, for comparative purposes, the acute toxicities of di- and 



