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5
Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
DOI: 10.4408/IJEGE.2014-01.O-01
P
atrizia
TrefileTTi
(*)
, i
laria
PieTrini
(**)
, D
ario
rigamonTi
(*)
& l
uca
alberTi
(**)
(*)
Tethys srl - Viale lombardia 11 - 20131 milan, italy
(**)
Politecnico di milano, Dipartimento ingegneria Civile e ambientale (D.i.C.a.), ed. 9, Sezione geoscienze - 20133 milan, italy
e-mail: patrizia.trefiletti@tethys-geco.it - ilaria.pietrini@polimi.it - dario.rigamonti@tethys-geco.it - luca.alberti@polimi.it
ApplicAtion of compositionAl fingerprinting
to An itAliAn site contAminAted by hydrocArbons
eXtended AbstrAct
l’analisi della composizione di una miscela inquinante, costituita da petrolio o dai suoi prodotti di raffinazione, può dare utili informazioni
circa l’origine della contaminazione e i processi da essa subiti, attraverso l’identificazione di composti omologhi e di parametri di
correlazione che consentono di tracciare il percorso e la storia della contaminazione stessa. Questo risulta particolarmente importante
qualora esistano più potenziali sorgenti di inquinamento e si voglia individuare il responsabile, come ad esempio nel caso di due stazioni
di servizio adiacenti o quando su una stessa area si succedono diversi proprietari.
in questo articolo viene presentato un caso di applicazione di tecniche di fingerprinting composizionale per la caratterizzazione di un sito
contaminato da idrocarburi, collocato nell’italia settentrionale. nell’area di studio sorge una stazione di servizio con un distributore di
carburante distaccato, ma in passato il sito, ora sede del solo punto di ristoro, era suddiviso in due zone che includevano un punto ristoro di
dimensioni inferiori all’attuale e un distributore di carburante, proprietà di un’altra società. Durante lo scavo per l’espansione di un edificio, è
stata riscontrata una contaminazione da idrocarburi, fatto che ha determinato la necessità di attribuire la responsabilità della contaminazione e
quindi l’onere della bonifica a una delle due società interessate. a tale scopo sono stati prelevati dagli scavi 7 campioni di terreno e sottoposti ad
analisi di fingerprinting composizionale per determinare la sorgente di contaminazione degli idrocarburi e la loro età di rilascio nell’ambiente.
Sebbene le tecniche di fingerprinting siano ben note nella letteratura scientifica, la loro applicazione in italia risulta essere ancora scarsamente
diffusa. Quando si parla di contaminazione da idrocarburi in realtà si indica una contaminazione costituita da una miscela di alcune centinaia di
composti. il fingerprinting composizionale, attraverso lo studio di classi contaminanti omologhi presenti, permette di identificare tali composti
e conseguentemente di distinguere la tipologia di contaminazione (es. benzina, gasolio, cherosene) e l’età di rilascio. in particolare attraverso
la valutazione dei rapporti tra specifici composti della miscela indici del livello di degradazione subito dalla contaminazione, nel caso di studio
sono state condotte analisi mediante gC-mS sia su idrocarburi volatili (composti leggeri quali benzene, toluene, etilbenzene e xileni_bTeX e
gli additivi utilizzati come antidetonanti utilizzati nelle benzine quali metil ter-butiletere_mTbe, dibromoetano_1,2-eDb e dicloroetano_1,2-
eDC) che semivolatili e/o non volatili (famiglie omologhe di idrocarburi) presumibilmente presenti nell’area. nei 6 campioni prelevati a
4 e a 5 m dal piano campagna, è stata riscontrata la presenza di idrocarburi semivolatili e/o non volatili, la miscela era infatti caratterizzata
dall’assenza di bTeX e antidetonanti. Questo ha consentito di escludere che potesse trattarsi di un prodotto leggero, quale la benzina.
i composti omologhi rilevati hanno invece permesso di affermare che per 2 campioni (f5_1 e f5_2, prelevati a fondo scavo) la
contaminazione è legata esclusivamente a gasolio. in particolare la concomitante presenza degli isoprenoidi pristano (i-C
19
) e fitano (i-C
20
)
e l’alta abbondanza degli idrocarburi policiclici aromatici (iPa) fenantrene, dibenzotiofene e di C
4
-naftalene, supportano la conclusione
che si tratti di un gasolio altamente degradato. anche nel campione f2 (prelevato lungo la parte meridionale dello scavo) non sono stati
trovati prodotti idrocarburici leggeri, ma sono stati complessivamente riscontrati composti attribuibili a un prodotto più pesante del gasolio
(olio lubrificante). in particolare l’assenza di isoprenoidi e la relativa abbondanza di C
4
-fenantrene e C
4
-dibenziotiofene supportano questa
conclusione. infine nell’ultimo gruppo di campioni (f1, f3 e f4_prelevati rispettivamente lungo la parete settentrionale, occidentale
ed orientale) è stata riscontrata la presenza di un range di prodotti idrocarburici più ampio che oltre al gasolio comprende una frazione
idrocarburica più leggera (probabilmente cherosene) e una più pesante (olio lubrificante).
i vari composti contenuti nei prodotti di raffinazione sono più o meno sensibili alla biodegradazione e per questo motivo è possibile definire una
sequenza temporale con cui questo processo influisce sulle alterazioni dei prodotti, a partire dagli n-alcani (più suscettibili alla biodegradazione)
sino ai terpani (più recalcitranti) , permettendo valutazioni sulle variazioni della composizione dell’ intera miscela contaminante nel tempo. nel
caso in esame è possibile riscontrare una generale deplezione degli n-alcani a catena più corta e degli iPa con il minor numero di gruppi metile.
al fine di stimare il tempo intercorso dal rilascio di un gasolio in ambiente naturale è possibile utilizzare il rapporto tra eptadecano (n-alcano
con 17 atomi di carbonio) e pristano (isoprenoide con 19 atomi di carbonio) che per il caso in esame ha fornito un’età della contaminazione
compresa tra 15 e 25 anni. l’assenza di contaminazione legata a benzine, oggi ancora utilizzate nel sito, e la forte degradazione dei prodotti
ritrovati nel sottosuolo, hanno pertanto permesso di attribuire l’evento inquinante al proprietario precedente dell’area.
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p. trefiletti, i. pietrini, d. rigAmonti & l. Alberti
6
Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
AbstrAct
in this paper, a case study of compositional fingerprinting appli-
cation to characterize an italian site, with evidence of hydrocarbons
contamination, is presented. Though the fingerprinting approach is
not widely used, especially in italy, this methodology permits to
identify the type of contamination and its level of degradation by
the study of the homologues classes of contaminants present in the
mixtures. in characterization of contamination due to spillage of
diesel, through the use of specific ratios between compounds of the
mixture, it is possible to determine the contaminant grade of altera-
tion and thus gives a prediction of the contamination age. in case
study here presented, using the ratio heptadecane/pristane (n-C
17
/
pr), a prediction of the contamination age was carried out for the
identified diesel contamination. These aspects are also fundamental
for a correct characterization of the site and therefore to choose the
most suitable site-specific remediation strategy. all these data, com-
bined with the usual geochemical analysis, can give an added value
in order to assess the responsibility of contamination and therefore
the duty of reclamation, especially in case of different owners. in
this way, a successful reclamation, from the point of view of both
the expected results and the economic view, is possible.
K
ey
words
: hydrocarbons contamination, compositional fingerprinting,
characterization, remediation
introduction
Thousands of chemicals with different properties and toxicity
are daily employed in our modern and industrialized world and
many of them can be detected in all the compartments of the envi-
ronment (e.g., water, sediment, soil, air and biota). Contaminants
of particular interest are the refined products of crude oil since,
nowadays, fossil fuels cover almost the totality of the amount of
energy needed. in fact, refined products are used as fuels in cars
(gasoline and diesel), aircrafts (jet fuels) and ships (heavy fuel oil);
for heating and electricity generation, as lubricants in machinery;
as asphalt for road building and in the production of chemicals and
plastics. as consequence, the exploration, the production, the trans-
portation and the widespread use of this family, inevitably result in
contamination of the environment (a
limi
et alii, 2001).
gasoline, diesel and lubricants, are the end products of the re-
fining process of the petroleum. more in general, the term “petro-
leum” refers to the family naturally occurring (e.g. gases: natural
gases; liquids: gas condensates and crude oils; solid: bitumen and
oil shale/sand) that contain complex mixtures with ten thousands
of hydrocarbons and non-hydrocarbons (nitrogen-, sulfur- oxy-
gen- and metal containing compounds). The chemical, physical
(i.e. aPi gravity and sulfur content), and compositional (such
as ratio pristane/phytane and percentage of benzothiophenes)
properties of the petroleum vary with the different geographical
origin. The refined products maintain these differences plus the
ones related to the refining processes actuated in the different re-
fineries. moreover, each refined products has its fingerprints that
is due to its chemical composition, i.e. the typical hydrocarbon
range of gasoline is C
3
-C
12
, while in diesel is C
15
-C
25
and in the
residual oils, carbons range from 14
to more than 40
(H
eat
et alii,
1993; K
aPlan
et alii, 2001; o
Debunmi
et alii 2002).
in addition, gasoline and diesel fuels have a variety of addi-
tives. most of these are required for the purpose of lubricating and
keeping engine parts clean; they consist of detergents and antioxi-
dants and are considered proprietary by the various refineries that
are using them and thus their composition is not available. for the
purpose of assignment of source, most of the additives are not very
useful because many of them have similar chemical compositions
and may not be easily differentiated and furthermore they decom-
pose relatively quickly in water and may be not strong adsorbed on
soil particles. in this concern, the two organohalogenated, ethylene
dibromide (1,2-eDb) and ethylene dichloride (1,2-eDC) are of par-
ticular importance; in fact, the search of the these additives can give
useful information to date gasoline because in italy, until 1988, they
were added as anti-knocking or post-combustion gas evacuating.
Since the type and the amount of additives have changed with time,
the identification and quantification of the two organic compounds
in a free phase product is very useful even because, on the contrary
of lead alkylates that hydrolyze in water, they tend to be more per-
sistent and so more easily surveyed for a longer period (K
aPlan
et
alii, 1997). another additive used in gasoline is the methyl Terti-
ary-butyl ether (mTbe) and its presence indicates a more recent
pollution because it was introduced after the end of the eighties,
beginning of nineties, in the lead-free gasoline as substitute of the
lead additives (S
tern
& K
neiSS
, 1997; K
aPlan
et alii, 1997).
furthermore, once in the environment crude oils and refined
products are subjected to physical (e.g., evaporation, emulsifica-
tion, natural dispersion, dissolution and sorption), chemical (e.g.,
photodegradation) and biological (e.g., microbiological degrada-
tion or biodegradation) weathering processes that lead to the altera-
tion of their chemical composition and thus of their fingerprints (or
chromatograms). Specifically, the different compounds contained
in the refined products are more or less susceptible to biodegrada-
tion due to their chemical structures. for this reason it is possible
to define a temporal sequence starting from the n-alkanes (more
susceptible to biodegradation) to the terpanes (less susceptible),
leading to the possibility to evaluate compositional changes of the
whole contaminant mixture during the time (D
ouglaS
et alii, 1996;
K
aPlan
et alii, 1996; W
ang
et alii, 1998; U.S. ePa 1999; m
urPHy
& m
orriSon
, 2002). This is the core of the analytical methodol-
ogy called “compositional fingerprinting”, based on the use of a
gas chromatography - mass spectrometry (gC-mS) and that al-
lows to the identification of the type of contamination and of its
source among different possible sources and, furthermore, permits
the determination of degradative effects on it (n
orDteSt
m
etHoD
,
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ApplicAtion of compositionAl fingerprinting to An itAliAn site contAminAted by hydrocArbons
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
-of the market, organolectic evidences of a potential contamination
by hydrocarbons were found in the soil. Since the previous division
of the area showed the presence of a fuel station, an analytical inte-
gration by the use of compositional fingerprinting has been carried
out to determine the type of contamination and its possible age. a
total of seven soil samples have been collected from the four walls
and the bottom of the excavation in the following way (fig. 1b):
- one sample for each wall of the excavation at a depth of about
4 meters from the ground level (sample f1-northern wall, f2
-southern wall, f3 western, and f4 - eastern wall),
- one sample on the eastern wall at a depth of about 1 meter
from the ground level (f4_1), and
- two samples at the bottom of the excavation, at a depth of
about 5 meters from the ground level (samples f5_1 and
f5_2), in the surrounding of the area characterized by a
strong smell of hydrocarbons.
mAteriAls And methods
SamplInG
The samples were collected in sampling containers of glass
fully filled with sampled soils, in order to avoid headspace and
thus the loss of volatile compounds according to the protocol U.S.
ePa SW-846 (ePa, 2007, Chapter 4).
HEaDSpacE analySIS
all the samples were analyzed to determine the concentra-
tion of volatile aromatic hydrocarbons bTeX (benzene, toluene,
ethylbenzene and xylenes), of the oxygenate compound mTbe
and of the additives 1,2-eDb and 1,2-eDC. The vials for the
headspace analyses, containing 6 ml of the water samples plus
1991; W
ang
et alii, 1997; W
ang
et alii, 1999; D
aling
et alii, 2002;
b
eKinS
et alii, 2005; c
HriStenSen
& t
omaSi
, 2007, H
oStettler
et
alii, 2013). The compositional methodology pursues these aims
by the analysis of the contaminants composition, evaluating the
presence and the abundance of individual compounds and quanti-
tatively determining several ratios useful to measure the biodegra-
dation degree, such as, for diesel, n-C
17
/pristane and n-C
18
/phytane,
whereas n-alkanes (n-C
17
or heptadecane and n-C
18
or octadecane)
are correlated to the isoprenoids pristane and phytane. This because
bacteria preferentially consume the n-alkanes leading to a relative
enrichment in abundances of isoprenoids that are less susceptible
to biodegradation (a
limi
et alii, 2003; S
tout
, 2003; W
ang
et alii,
2003a; W
ang
et alii, 2003b, W
ang
et alii, 2003c).
The accurate characterization of polluted sites is still a chal-
lenge and the ongoing research is focused on the definition of valu-
able tools of analysis able to reduce the uncertainties that affect it.
During this study, the compositional fingerprinting has been applied
to identify the soil contamination and trying to define its relative age
in order to assess the responsibility of the contamination. These two
aspects are also fundamental to better characterize the site and then
to choose the most suitable remediation strategy both from the point
of view of the expected results and from the cost of remediation.
site cAse study
The area of study covers almost 2,500 m
2
(fig. 1a) and it is
located in a region in the central italy. at the present, in the studied
site it is located a service area with a separated fuel station, but in
the past the area of the market was divided into two zones includ-
ing a smaller market than the actual and a fuel station owned by a
different company. During the excavation for the construction of a
basement, planned in the context of expansion of existing buildings
Fig. 1 - Geographical localization of the site of study: (a) map of the area; (b) excavation with samples location
(a)
(b)
m
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p. trefiletti, i. pietrini, d. rigAmonti & l. Alberti
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
7.2 g of carbonate potassium (K
2
Co
3
) were incubated at an in-
cubation temperature of 85°C for 50 min in a heating block in
agitation (speed of 250 rpm). The syringe temperature of the au-
tosampler was 90°C. The gC temperature was first held at 40°C
for 8 min, then increased to 180°C at a rate of 5°C/min and held
for 2 min. Helium served as carrier gas.
The results of the gC-mS analyses showed the absence of these
three classes of compounds allowing to suppose that these samples
are not characterized by a contamination due to spillage of gasoline.
FUll Scan analySIS
The samples analyzed with the purpose to determine the semi-
volatile and non-volatile fraction were extracted in two different
ways, depending on the compounds researched. The Total Petro-
leum Hydrocarbons (TPH) have been extracted by ultrasonic ex-
traction in acetone followed by clean up of the extract with a 6
ml column containing florisil and sodium sulfate (purchased from
Thermo Scientific). Differently, the sample for the identification of
the homologue compounds families have been treated extracting
the contaminants in a soxhlet with a mixture of 50% methylene
chloride and 50% acetone v/v (total volume 100 ml). The extracts
where then analyzed as following; the temperature of the oven in
the gC was first held at 40°C for 5 min, then increased to 300°C at
a rate of 10°C/min and held for 20 min. Helium served as carrier
gas and the mass analysis range was m/z 40-1050.
RESUltS anD DIScUSSIOn
The results of gC-mS analyses showed the absence of the
oxygenate compound mTbe and of the anti-knock additives 1,2-
eDb and 1,2-eDC allowing to suppose that these samples are not
characterized by a contamination due to a spillage of gasoline.
Contrarily, the analysis of the semivolatile compounds re-
vealed that the only sample that does not appear to be contami-
nated by hydrocarbons is the f4_1 (eastern wall, take at about 1
meter of depth), while the chromatograms relative to n-alkanes
(ion m/z 85) and isoprenoids (m/z 113) of the other samples show
three different situations; the samples f5_1 and f5_2 can be
grouped together, in the same way the samples f1, f3 and f4 can
be grouped, whereas the sample f2 represents a group by itself.
SamplES F5_1 anD F5_2
figure 2 shows the chromatograms of the samples collected
from the bottom of the excavation. These chromatograms reveal
that the samples f5_1 and f5_2 are contaminated by a diesel highly
degraded, exposed to environmental processes of attenuation for a
considerable period of time. in fact, the chromatograms, very simi-
lar among them, are characterized by the complete absence of n-
alkanes and by the apparent abundance of the isoprenoids pristane
(i-C
19
) and phytane (i-C
20
), which are characteristic of the diesel
used for cars or as heating fuel.
moreover, the analysis of the chromatogram relative to the
Fig. 2a - n-alkane chromatograms of the F5_1
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ApplicAtion of compositionAl fingerprinting to An itAliAn site contAminAted by hydrocArbons
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
homologues family of the alkylated cyclohexanes (CHs) (fig. 3a)
and the pattern of distribution of the polycyclic aromatic hydrocar-
bons (PaHs_fig. 3b) provide additional support to the hypothesis
that the contamination is due to spillage of diesel. in this case, due
to the high similarity between the two samples, only the figures
relative to the samples f5_1 are reported as example. The cited
chromatogram (fig. 3a) shows the higher abundances of CH-7 and
CH-8, characteristic of the diesel fingerprint and no compounds
with a chain shorter than CH-5, supporting the thesis of a contami-
nation highly degraded (H
oeStettler
& K
venvolDen
).
furthermore, the histograms in fig. 3b show a high abun-
dance of phenanthrene and dibenzothiophenes, characteristic of
the fingerprints of diesel and heavier fraction, and the presence of
C
3
and C
4
-naphthalene; the latter are not included in lighter frac-
tions and this is a further confirmation of the absence of gasoline
fuels. in addition, the removal of C
0
and C
1
-naphthalene, C
0-
phen-
anthrene, C
0
-dibenzothiophene and the relative increase of C
3
-
naphthalene, C
2
-phenanthrene and C
2
-dibenzothiophene are other
evidences of the high level of degradation of the contamination.
SamplES F1, F3 anD F4
in the chromatograms of the samples f1, f3 and f4 it is possi-
ble to determine the presence of three different ranges of distribu-
tion of hydrocarbons, identifiable as diesel highly degraded, as for
the samples collected at the bottom of excavation, together with
a lighter fraction (probably kerosene) and a heavier one (fig. 4).
The chromatograms for these samples are very similar among
them and are characterized by the presence of the C
17
and C
18
n-
alkanes in the typical region of middle distillates, n-alkanes be-
tween the n-C
12
and n-C
16
(range of light distillates) and between
n-C
30
and n-C
36
(range of heavy distillates).
another evidence of the presence of diesel fuel is done by
the identification of the isoprenoids pristane and phytane. The
light fraction may be composed by degraded kerosene, because
the fresh product is characterized by a range of number of car-
bons between 9 and 16 with the n-alkanes decane (n-C
10
), un-
decane (n-C
11
) and dodecane (n-C
12
) as main compounds (fig.
5) and that are absent or are highly depleted in the sample an-
alyzed, while are still identifiable the n-alkanes with a longer
chain (from n-C
13
to n-C
16_
, fig. 4).
moreover, the pattern of distribution of the PaHs shows a
high abundance of naphthalene and phenanthrene. Unlike the pre-
vious group, the isomers of the dibenzothiophene show a lower
abundance than that of the other two PaHs (fig. 6; the sample
f3 is taken as example of this group). Dibenzothiophenes are not
present in lighter refined products, as kerosene, while these prod-
ucts are rich of naphthalene. The pattern of distributions of the
PaHs seems a snapshot of the mixed situation revealed by the
chromatograms of the n-alkanes.
Fig. 2b - n-alkane chromatograms of the F5_2 samples
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p. trefiletti, i. pietrini, d. rigAmonti & l. Alberti
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
SamplE F2
Differently from all the other samples, the sample f2 shows
a chromatogram relative to n-alkanes ranging from n-C
30
to n-C
36
(fig. 7.a). in this sample isoprenoids were not identified. also
the pattern of distribution of the PaHs differs from the other be-
cause shows the presence of C
4
-phenanthrene and the C
4
-diben-
zothiophene characteristic of the heavier fractions. Histograms
reveal also a high abundance of naphthalene (mainly C
3
and C
4
that are not present in light products) and of phenanthrene and
dibenzothiophene in general. also in this case the removal of C
0
and C
1
-naphthalene, C
0
-phenanthrene and the relative increase of
C
3
-naphthalene, C
2-
phenanthrene, C
2
and C
3
-dibenzothiophene
are evidences of the contaminant degradation (fig. 7b).
conclusions
a common element in all the samples analyzed is the
heightened state of degradation to which seems to have been
subjected the contaminant fuels (such as diesel and kerosene).
Fig. 3 - Sample F5_1 (a) alkylcyclohexanes chromato-
gram and (b) paHs pattern distribution (rela-
tive abundance)
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ApplicAtion of compositionAl fingerprinting to An itAliAn site contAminAted by hydrocArbons
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
Fig. 4b - n-alkane chromatograms in F3
Fig. 4a - n-alkane chromatograms in F1
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
This finding leads to suppose that is present an old contamina-
tion subjected to processes of biodegradation. in order to quan-
titatively estimate the time elapsed, from the spill of diesel, it
is possible to determine the C
17
/pristane and C
18
/phytane ratios
for diesel contamination (c
HriStenSen
& l
arSen
, 1993; a
limi
et alii, 2003), as in the compounds unaltered, the n-alkanes C
17
and C
18
are much more abundant compared to isoprenoids while
this situation is reversed in the compounds altered, since the mi-
croorganism present in the environment preferentially consume
the n-alkanes. Christensen and larsen (1993) shown that once
in the environment, the relationship n-C
17
/pristane, typical of
gas oils, decreases due to the biodegradation from the original
value in the diesel unaltered to values close to 0 in approxi-
mately 20-25 years. This situation occurs in the samples taken
from the bottom of the excavation f5_1, f5_2 and f3 where the
n-alkanes appear to be completely removed while in samples
f2 and f4 the relationship C
17
/pristane assumes the value of 0.8
which leads to a date of approximately 13 years.
furthermore, the n-alkanes are not the only compounds to
be reduced; in fact there is evidence of degradation at the level
Fig. 4c - n-alkane chromatograms in F4 samples
Fig. 5 - n-alkanes (c
9
-c
16
) pattern in the standard of kerosene
Fig. 6 - pattern distribution (relative abundance) of the
paHs in the sample F3
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Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
of PaHs (less susceptible than the n-alkanes to biodegradation)
and alkylcyclohexanes leading to the conclusion that the die-
sel contamination is highly altered (level of alteration 6/7), as
showed by a
limi
et alii (2003).
Considering all these factors, it can be concluded that the finger-
printing methodology was useful to identify the type of contamina-
tion, constituted mainly by degraded diesel (the refined product was
not present only in the sample f2, among the contaminated samples)
with also the presence of higher and lighter fractions. Since all these
contaminants are amenable to refined products, normally used by
fuel station, and the proposed dating for diesel contamination ranges
from 13 to 25 years, the data suggests that the responsibility of the
contamination and therefore the duty of the reclamation can be at-
tributable to the fuel station previously located in the site.
Acknowledgments
Thanks to the Professor andrea mele and the Dipartimento di
Chimica, materiali e ingegneria Chimica”giulio natta”, Politec-
nico di milano (italy), where the gC-mS (property of Tethys srl),
used in this study, is located.
Fig. 7 - Sample F2 (a) n-alkanes chromatogram,
(b) pattern distribution (relative abun-
dance) of the paHs
background image
p. trefiletti, i. pietrini, d. rigAmonti & l. Alberti
14
Italian Journal of Engineering Geology and Environment, 1 (2014)
© Sapienza Università Editrice
www.ijege.uniroma1.it
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Received march 2014 - accepted april 2014
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