I'r - Memorial University of Newfoundland

It is difficult to differentiate between the relative importance ofcar soot and fire soot
end members. As the car soot member demonstrates the widest rangeofstatistical
variation. it always overlaps with the range for fire soots. However. an increased
influence ofroad sweeps can be established for a nwnber ofstations. For example, the
station at Buffalo consistently plots closer to the crankcase oil-road sweep mixing curve
(Fig. 4.2.8, 4.2.11, 4.2.134.2. L7). The graphs demonstrate that as much as 80-90%of
PAH at this station derive from this secondary source. Contributi on from the road
sweeps may also be important at sites 955, 84. %2, 23, and935 (Fig. 4.2.8, 4.2.1 L,
4.2.15. 4.2.16).
To conclude. the PAH assemblage in most samples can be attributed to mixing of
four primary and secondary sources. However, there are a few stations (especially 1021,
946.966) where previously unidentified sources might influence the isotopic composition
of PAH . The contribution from combustion sources seem to be predominant throughout
the lake. Neverthe less, petroleum sources are important at some stations in the Western
Basin and the northern part ofthe Central Basin. Finally, at stations located closer to the
southern shore in the Central and Eastern Basins, the contribution ofroad sweeps can also
be important (955. 84, 962, 23. and 935). This importance is especially well seen at
Buffalo where it is close to 100"/0.
4.2.2.1 Pet f or isotopiccomposition (source identification)
As in the case with molecular composition, the final step to generalization ofresults
was made through app lication ofmultivariate statistics (Appe ndix. 84; for more
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