Environmental Engineering Reference
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pyrogenic inputs, probably because FP1/FP0 < 1 for some petrogenic sources such
as coals (Fig. 13 ; Yunker et al. 2002 ). The FP1/FP0 and the PA1/PA0 ratios may not
correlate with emissions from old vehicles (Yan et al. 2006 ; Yunker et al. 2002 ).
Yunker et al. ( 2002 ) suggested that the FP1/FP0 ratio is better used for detecting
combustion and is less variable than the PA1/PA0.
Sporstol et al. ( 1983 ) showed that the alkyl fluoranthene plus pyrene (alkylation
level: 1-3) homologue distributions of soot and oil differ significantly. The ratios
FP
0
BC
CC
0
23
of
and
(proportion of alkylated PAHs) were used by Stout
FP
2
+
FP
3
+
et al. ( 2003 ) to classify pyrogenic and petrogenic sources. These thermal parameters
range from 1.9 to 3.6 for pyrogenic sources, whereas petrogenic values (crudes)
FP
0
range from 0.05 to 0.06 (Stout 2007 ). In coal tars, the
ratio is more
FP
2
+
FP
3
prone to changes from evaporation than from biodegradation (Uhler and Emsbo-
Mattingly 2006 ). Thus, caution is advised when applying FP0/FP2 + FP3 to differ-
ent matrices.
Methylpyrenes and benzofluorenes (MW 216) are relatively stable isomers that
are suitable for comparing light fuel oils (e.g., gas oil), which rapidly degrade in the
environment (Dahlmann 2003 ; Hansen et al. 2007 ; Uhler and Emsbo-Mattingly
2006 ). In addition, the ratios of benzo[ a ]luorene/4-PY1, benzo[ b + c ]luorene/4-
PY1, 1-PY1/4-PY1 and 2-PY1/4-PY1 are recommended in the oil spill identification
methodology of the European Committee for Standardization (Hansen et al. 2007 ).
Roush and Mauro ( 2009 ) used the benzofluorenes to methylpyrene ratio to
exclude petroleum as having contaminated soils and sediments. Contamination
from coal tar or creosote is possible if this ratio is >1. Craig and Mauro ( 2012 )
reported that, in sediments contaminated with coal tar, the ratio of benzo[ b + c ]luo-
rene to monomethylpyrenes is little changed by weathering and can be used to dis-
criminate sources such as coal tar (3.9) and MGP tar (1.5).
The PAH pyrogenic indicator (PPI)—not to be confused with the pyrogenic
index (Sect. 5.8 )—is the PPP
FP
234
0
++ ratio (Fig. 14 ). It reflects the relative abun-
dance of petrogenic PAHs and decreases as the pyrogenic contamination increases
(Bence et al. 2007 ; Luo et al. 2008 ; Page et al. 1999 ). According to Neff et al.
( 2005 ), the PPI is almost always higher than 9 for petrogenics (50-100 for Exxon
Valdez crude at different stages of weathering) and lower than 0.3 for pyrogenic
PAHs. If TPAH >0.1 ʼg/g, and PPI < 4, then the PAH contamination probably has a
pyrogenic component (Bence et al. 2007 ; Neff et al. 2006 ; Page et al. 1999 ). Values
of PPI for wood burning and creosote have also been reported (Fig. 14 ; Neff et al.
2006 ; Page et al. 1999 ).
The PPI has been used to show that forest fire fallout contributed to PAHs in
nearshore subtidal sediments (Page et al. 1999 ). The PPI was used to differentiate
petrogenic from pyrogenic PAHs in sediments and biological samples at the site
of the 1989 Exxon Valdez oil spill, and also in other cases (Neff et al. 2005 , 2006 ;
Pies et al. 2008 ). Bence et al. ( 2007 ) showed that PPI is unaffected by weathering.
 
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