Patterns of PCDD, PCDF, and PCB contamination in Great Lakes fish and birds and their characterization by principal components analysis

Contamination of the Great Lakes with polychlorinated dibenzo- p -dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) has created concern because of the adverse effects of these chemicals on fish and wildlife. In addition, the use of fishery resources for recreation and food can be limited if harmful concentrations of these contaminants occur. Concerns about these residues are based on the observations that PCDDs and PCDFs in fish and birds are composed primarily of the highly toxic 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) and 2,3,7,8-tetrachloro-dibenzofuran (TCDF) and other 2,3,7,8-chlorine substituted penta- and hexa-chlorodibenzo- p -dioxins and -furans. The concentrations of 2,3,7,8-TCDD in fish and birds are greatest in regions where chlorinated organic chemicals are manufactured or near hazardous waste sites. The application of SIMCA, a principal components chemometric method, demonstrated that residue profiles differed between regions sampled. Ratios of PCDFs to PCDDs in the bird eggs examined were smaller than those observed in fish — perhaps indicating that in birds the rate of metabolism of PCDFs is higher than that of PCDDs.