Gschwend%20thesis.pdf

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The naphthalene-to-methyl napthalenes ratios are plotted for all
the year-round samples in figure 3-15. A sinusoidal pattern is apparent
with low ratios in the summer and high ones in the winter. The March,
1977 sample was contaminated by the oil spill and consequently had a
very low ratio.
Also shown (figure 3-15) are the ratios found in laboratory studies
of various possible sources of these aromatic compounds. Gasoline,
gasol ine and oil for outboards, diesel fuel, and API standard no. 2 fuel
oil were diluted and analyzed directly by GC. Car exhaust and diesel
exhaust were collected in glass flasks, stripped onto charcoal traps,
extracted with CH2Cl2, and analyzed by GC. These exhausts were also
connected to flasks containing exhaustively prestripped Seawater (gently
stirred) and allowed to exchange the volatiles between the vapors in one
flask and the water in the other. After one day, the water was stripped
and chromatography was performed on the volatile concentrate.
These source data, in conjunction with the year-round pattern,
suggest that more direct inputs to coastal seawater occurred in the
summer than in the winter. The ratios seen in the winter samples indicate
that a good deal of fractionation must have taken place to produce such
high values from any of the known sources. The general trend in the
experimental data was to increase the ratio by burning a fuel and to
increase it still further by atmospheric transport. Therefore, these
data may indicate that atmospheric sources become more important in the
winter (e.g., from the burning of home heating oil).
A significant concentration of naphthalene was also found in the
restrips (figure 3-14). This suggests that this compound was somehow
unavailable for exchange into the vapor phase of the purging bubbles.
The relatively low air-water partition coefficient (O.016 as compared
l.