3,3',4,4',5,5'-hexachlorobiphenyl (Stalling et al . 1985a, b). For example, 

 analytical results of fish, birds, and sediments indicated that every sample 

 that was positive for 2,3,7,8-TCDD also contained 2,3,7,8-chlorine substituted 

 dibenzofurans (Stalling et al. 1985a, b). 



