Abstract: Natural hydrocarbon seepage has helped petroleum
exploration as a direct indicator of gas and/or oil subsurface
accumulations. Surface macro-seeps are generally an indication of a
fault in an active Petroleum Seepage System belonging to a Total
Petroleum System. This paper describes a case study in which
multiple analytical techniques were used to identify and characterize
trace petroleum-related hydrocarbons and other volatile organic
compounds in groundwater samples collected from Sousse aquifer
(Central Tunisia). The analytical techniques used for analyses of
water samples included gas chromatography-mass spectrometry (GCMS),
capillary GC with flame-ionization detection, Compound
Specific Isotope Analysis, Rock Eval Pyrolysis. The objective of the
study was to confirm the presence of gasoline and other petroleum
products or other volatile organic pollutants in those samples in order
to assess the respective implication of each of the potentially
responsible parties to the contamination of the aquifer. In addition,
the degree of contamination at different depths in the aquifer was also
of interest. The oil and gas seeps have been investigated using
biomarker and stable carbon isotope analyses to perform oil-oil and
oil-source rock correlations. The seepage gases are characterized by
high CH4 content, very low δ13CCH4 values (-71,9 ‰) and high
C1/C1–5 ratios (0.95–1.0), light deuterium–hydrogen isotope ratios (-
198 ‰) and light δ13CC2 and δ13CCO2 values (-23,8‰ and-23,8‰
respectively) indicating a thermogenic origin with the contribution of
the biogenic gas. An organic geochemistry study was carried out on
the more ten oil seep samples. This study includes light hydrocarbon
and biomarkers analyses (hopanes, steranes, n-alkanes, acyclic
isoprenoids, and aromatic steroids) using GC and GC-MS. The
studied samples show at least two distinct families, suggesting two
different types of crude oil origins: the first oil seeps appears to be
highly mature, showing evidence of chemical and/or biological
degradation and was derived from a clay-rich source rock deposited
in suboxic conditions. It has been sourced mainly by the lower
Fahdene (Albian) source rocks. The second oil seeps was derived
from a carbonate-rich source rock deposited in anoxic conditions,
well correlated with the Bahloul (Cenomanian-Turonian) source rock.
Abstract: The cuticular hydrocarbons of Pamphagus elephas
(Orthoptera: Pamphagidae) has been analysed by gas
chromatography and by combined gas chromatograph-mass
spectrometry. The following hydrocarbon classes have been
identified in insect cuticular hydrocarbons are: n-alkanes and
methylalkanes comprising Monomethyl-, dimethyl-and
trimethylalkanes. Sexual dimorphism is observed in long chain
alkanes (C24-C36) present on male and female. The cuticulars
hydrocarbons of P.elephas ranged from 24 to 36 carbons and
incluted n-alkanes, Dimethylalkanes and Trimethylalkanes. nalkanes
represented by (C24-C36,72,7% on male and 79,2% on
female), internally branched Monomethylalkanes identified were
(C25, C30-C32,C35-C37;11% on male and 9,4% on female),
Dimethylalkanes detected are (C31-C32, C36; 2,2% on male and
2,06% on female) and Trimethylalkanes detected are (C32, C36;
3,1% on male and 4, 97 on female). Larvae male and female (stage
7) showed the same quality of n-alkanes observed in adults.
However a difference quantity is noted.
Abstract: 15 strains of oil-destructing microorganisms were
isolated from oil polluted soil of Western Kazakhstan. Strains 2-A
and 41-3 with the highest oil-destructing activities were chosen from
them. It was shown that these strains oxidized n-alkanes very well,
but isoalkanes, isoparaffin, cycloparaffin and heavy aromatic
compounds were destructed very slowly. These both strains were
tested as preparations for bioremediation of oil-polluted soil in model
and field experiments. The degree of utilizing of soil oil by this
preparation was 79-84 % in field experiments.
Abstract: The concentrations of aliphatic and polycyclic aromatic hydrocarbons (PAH) were determined in atmospheric aerosol samples collected at a rural site in Hungary (K-puszta, summer 2008), a boreal forest (Hyytiälä,
April 2007) and a polluted rural area in Italy (San Pietro Capofiume, Po Valley, April 2008). A clear distinction between “clean" and “polluted" periods was observed. Concentrations obtained for Hyytiälä are significantly lower than those for the other two sites. Source reconciliation was performed using diagnostic parameters, such as the carbon preference index and ratios between PAH. The presence of an unresolved complex mixture of hydrocarbons, especially for the Finnish and Italian samples, is indicative of petrogenic inputs. In K-puszta, the aliphatic hydrocarbons are dominated by leaf wax n-alkanes. The long range transport of anthropogenic pollution contributed to the Finnish aerosol. Industrial activities and vehicular emissions represent major sources in San Pietro Capofiume. PAH in K-puszta consist of both pyrogenic and petrogenic compounds.