Primjena bioloških markera u identifikaciji zagađivača naftnog tipa u recentnim sedimentima - aluvijalna formacija rijeke Dunav, Rafinerija nafte Pančevo

The purpose of this paper was to examine to which extent the abundance and distribution of certain biological markers may be used for the identification of oil-type pollutants in recent sediments and ground waters. The samples were taken from the area of the Oil Refinery Pančevo (alluvial formation of the Danube River). The organic matter of the investigated samples was isolated using an extraction method with chloroform. The group composition and usual biological markers were analyzed in the obtained extracts. n-Alkanes and acyclic isoprenoids, pristane and phytane were analyzed using gas chromatographie (GC) analysis of saturated hydrocarbons. Polycyclic alkanes of the sterane and terpane type were analyzed using gas chromatography-mass spectrometry (GC-MS), i.e. by analyzing the carbamide non-adduct of the total alkane fraction (Single Ion Monitoring SIM-technique). The obtained results indicate that n-alkanes can be used for the identification of oil-type pollutants (for example, if the oil-pollutant is biodegraded or present in very low concentrations), and steranes and triterpanes can be used as very reliable indicators of oil-type pollution in recent sediments and ground waters.Cilj ovog rada bio je da se utvrdi u kolikoj mjeri se obilnosti i raspodjele pojedinih bioloških markera mogu upotrijebiti za identifikaciju zagađivača naftnog tipa u recentnim sedimentima i podzemnim vodama. Ispitivani su uzorci sa lokaliteta Rafinerije nafte Pančevo (aluvijalna formacija rijeke Dunav). Organska supstanca ispitivanih uzoraka izolovana je ekstrakcijom pomoću hloroforma. U dobivenim ekstraktima određen je grupni sastav i analizirani su najpoznatiji biološki markeri. n-Alkani i aciklični izoprenoidni alkani, pristan i fitan, analizirani su gasnohromatografskom (GC) analizom frakcije zasićenih ugljovodonika, a policiklični alkani tipa sterana i triterpana primjenom gasnohromato-grafsko-masenospekrometrijske (GC-MS) analize karbamidnog neadukta ukupnih alkana (Single Ion Monitoring SIM, tehnika), Dobiveni rezultati pokazali su da u slučajevima kada se n-alkani ne mogu upotrijebiti u identifikaciji zagađivača naftnog tipa (na primjer, ukoliko je naftni zagađivač biodegradovan i/ili prisutan u veoma niskim koncentracijama), sterani i triterpani mogu poslužiti kao veoma pouzdani indikatori prisustva ovog zagađivača u recentnim sedimentima i podzemnim vodama

Zechstein Main Dolomite oil characteristics in the Southern Permian Basin:I. Polish and German sectors

Geochemical analyses were used to classify 39 Zechstein (Late Permian, Lopingian) Main Dolomite (Ca2) crude oil samples from fields in the eastern and southern sector of the Southern Permian Basin (SPB) of Europe and to provide new insights into the origin of the oil. Geochemical data indicate that Ca2 oils were generated in the early-to-late oil window and are mostly non-waxy oils. Various biomarker and stable carbon isotopic ratios were used to identify source and depositional settings for source rocks of Ca2 oils arranged within 10 distinct oil groups. Specifically, the geochemical analyses and oil-oil correlations revealed a set of characteristic biomarkers including an even-over-odd predominance (EOP) for the C20-30n-alkanes, C40 carotenoid occurrence (isorenieratane, chlorobactane, β-isorenieratane), bisnorhopane/hopane (BNH/H) ratios >0.1, high abundances of C35 homohopanes and elevated concentrations of C32 and C34 homohopanes, a predominance of C29 homologues among 4-desmethyl steranes in the majority of oil samples, and a high abundance of diasteranes. Stable carbon isotopes and biomarkers provided ample evidence that Ca2 oils were generated from predominantly algal-rich marly carbonate/evaporite source rocks located in the lower slope/shallow-basin and lagoonal facies of the Ca2 basin, all deposited under suboxic-anoxic (euxinic) conditions. In the case of all higher maturity oils, the source rocks could not be reliably identified but high (>2) C24Tet/C23 values suggest a carbonate-evaporite depositional setting

Compilation of organic carbon distribution and sedimentology in the surface sediments on the continental margin offshore southwestern Africa

In this study we demonstrate the relevance of lateral particle transport in nepheloid layers for organic carbon (OC) accumulation and burial across high-productive continental margins. We present geochemical data from surface sediments and suspended particles in the bottom nepheloid layer (BNL) from the most productive coastal upwelling area of the modern ocean, the Benguela upwelling system offshore southwest Africa. Interpretation of depositional patterns and comparison of downslope trends in OC content, organic matter composition, and 14C age between suspended particles and surface sediments indicate that lateral particle transport is the primary mechanism controlling supply and burial of OC. We propose that effective seaward particle transport primarily along the BNL is a key process that promotes and maintains local high sedimentation rates, ultimately causing high preservation of OC in a depocenter on the upper slope offshore Namibia. As lateral transport efficiently displaces areas of enhanced OC burial from maximum production at highly productive continental margins, vertical particle flux models do not sufficiently explain the relationship between primary production and shallow-marine OC burial. On geologic time scales, the widest distribution and strongest intensity of lateral particle transport is expected during periods of rapid sea-level change. At times in the geologic past, widespread downslope lateral transport of OC thus may have been a primary driver of enhanced OC burial at deeper continental slopes and abyssal basins

Temperature reconstruction of sediment cores from the northeastern Arabian Sea

In order to reconstruct the monsoonal variability during the late Holocene we investigated a complete, annually laminated sediment record from the oxygen minimum zone (OMZ) off Pakistan for oxygen isotopes of planktic foraminifera and alkenone-derived sea surface temperatures (SST). Significant SST changes of up to 3°C which cannot be explained by changes in the alkenone-producing coccolithophorid species (inferred from the Gephyrocapsa oceanica / Emiliania huxleyi ratio) suggest that SST changes are driven by changes in the monsoon strength. Our high-(decadal)-resolution data indicate that the late Holocene in the northeastern Arabian Sea was not characterized by a stable uniform climate, as inferred from the Greenland ice cores, but by variations in the dominance of the SW monsoon conditions with significant effects on temperatures. Highest SST fluctuations of up to 3.0°C and 2.5°C were observed for the time interval from 4600 to 3300 years B.P. and during the past 500 years. The significant, short-term SST changes during the past 500 years might be related to climatic instabilities known from the northern latitudes ("Little Ice Age") and confirm global effects. Surface salinity values, reconstructed from delta18O records after correction for temperature-related oxygen isotope fractionation, suggest that in general, the past 5000 years were characterized by higher-than-recent evaporation and more intense SW monsoon conditions. However, between 4600 and 3700 years B.P., evaporation dropped, SW monsoon weakened, and NE monsoon conditions were comparatively enhanced. For the past 1500 years we infer strongly fluctuating monsoon conditions. Comparisons of reconstructed salinity records with ice accumulation data from published Tibetan ice core and Tibetan tree ring width data reveal that during the past 2000 years, enhanced evaporation in the northeastern Arabian Sea correlates with periods of increased ice accumulation in Tibet, and vice versa. This suggests a strong climatic relationship between both monsoon-controlled areas

Drmno lignite field (Kostolac basin, Serbia): Origin and palaeoenvironmental implications from petrological and organic geochemical studies

The objective of the study was to determine the origin and to reconstruct the geological evolution of lignites from the Drmno field (Kostolac Basin, Serbia). For this purpose petrological and organic geochemical analyses were used. Coal from the Drmno field is typical humic coal. Peat-forming vegetation dominated by decay of resistant gymnosperm (coniferous) plants, followed by prokaryotic organisms and angiosperms. Coal forming plants belonged to the gymnosperm families Taxodiaceae, Podocarpaceae, Cupressaceae, Araucariaceae, Phyllocladaceae and Pinaceae. Peatification was performed in neutral to slightly acidic, fresh water environment. Considering that organic matter of Drmno lignites was deposited at the same time, in the relatively constant climate, it could be supposed that climate probably had only small impact on peatification. Therefore, variations in compositions of macerals and biomarkers indicate changes in the water level, due to seasonal drying of the mire, which caused vegetation differences in the palaeoplant communities and changes of redox conditions (from anoxic to slightly oxic) during peatification. Diagenetic transformations of the organic matter were mainly governed by microbial activity, rather than thermal alteration