Presence and Potential Significance of o-o’-Unsubstituted PCB Isomers and Trace Aroclor® 1248 and 1254 Impurities

Abstract

Determination of the potential impact of PCB contamination on aquatic ecosystems is facilitated by information on the toxico-logical significance of specific PCB constituents. In support of this approach, recent studies, (Goldstein et al 1977 and Poland and Glover 1977), indicate that physiological activity associated with the technical PCB mixtures may be largely due to the presence of trace levels of PCB isomers having no o-o’-chlorine substitution. Hepatic enzyme induction from exposure to the most active of these isomers may approach that of the chlorinated-dibenzofurans and -dioxins. Separation and isolation techniques for structurally similar components of Aroclor^1/ mixtures are prerequisites for structure-toxicity correlation studies.