APPLICATION OF PATTERN-RECOGNITION TECHNIQUES TO ASSESSMENT OF BIOMAGNIFICATION AND SOURCES OF POLYCHLORINATED MULTICOMPONENT POLLUTANTS, SUCH AS PCBS, PCDDS AND PCDFS

Principal component analysis of PCB congeners and organochlorines in herring gull eggs from four of the Great Lakes reveals that, with the exception of Lake Erie, the two colonies within each lake contain distinctive patterns which did not change significantly between 1983 and 1990. Lake Ontario colonies were modelled by high percentages of mirex and photomirex, while high proportions of dieldrin, heptachlor epoxide and oxychlordane grouped the colonies in lakes Huron and Superior. The Middle Is. colony in the western end of Lake Erie showed high relative amounts of the higher chlorinated PCB congeners, due to continuing contamination from the Detroit R., or resuspension of contaminated sediments. PCDD/F patterns in the same colonies were dominated by 1,2,3,6,7,8 HxCDD and 1,2,3,7,8 PeCDD in lakes Erie, Huron and Superior while Lake Ontario patterns were dominated by 2,3,7,8 TCDD. Lake trout and walleye in the same lakes showed high levels of 2,3,7,8 TCDF which does not accumulate in herring gulls. It is concluded that the application of PCA techniques to Great Lakes data sets provides a useful screening procedure which can generate hypotheses on lake loading patterns and species residue differences by grouping samples with similar residue patterns.