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It is well known that during biodegradation of oil under natural geological conditions, or oil pollutants in the environment, degradation of hydrocarbons occurs according to a well-defined sequence. For example, the major changes during the degradation process of n-alkanes occur in the second, slight and third, moderate level (on the biodegradation scale from 1 to 10). According to previous research, in the fourth, heavy level, when intensive changes of phenanthrene and its methyl isomers begin, n-alkanes have already been completely removed. In this paper, the ex situ natural bioremediation (non-stimulated bioremediation, without addition of biomass, nutrient substances and biosurfactant) of soil contaminated with heavy residual fuel oil (mazut) was conducted during a period of 6 months. Low abundance of n-alkanes in the fraction of total saturated hydrocarbons in the initial sample (identification was possible only after concentration by the urea adduction technique) showed that the investigated oil pollutant was at the boundary between the third and the fourth biodegradation level. During the experiment, an intense degradation of phenanthrene and its methyl-, dimethyl- and trimethyl-isomers was not accompanied by the removal of the remaining n-alkanes. The abundance of n-alkanes remained at the initial low level, even at end of the experiment when the pollutant reached one of the highest biodegradation levels. These results showed that the non-stimulated biodegradation of some hydrocarbons, despite their high biodegradability, had not proceeded completely to the end, even at final degradation stages. Under the condition of reduced availability of some hydrocarbons, microorganisms tend to opt for the less biodegradable but more accessible hydrocarbons., Dobro je poznato da se u toku biodegradacije nafte u prirodnim geološkim uslovima, ili naftnog zagađivača u životnoj sredini, degradacija ugljovodonika odigrava prema definisanom rasporedu. Na primer, glavne promene u procesu razgradnje normalnih alkana dešavaju se u toku drugog, "blagog", i trećeg, "umerenog", stupnja (na skali biodegradacije od 1 do 10). Prema dosadašnjim istraživanjima, u četvrtom stupnju, kada počinju intenzivne promene fenantrena i njegovih metil izomera, normalni alkani su već u potpunosti uklonjeni. U ovom radu u toku perioda od 6 meseci izvođena je ex situ prirodna bioremedijacija (nestimulisana bioremedijacija bez dodatka biomase, hranljivih sastojaka i biosurfaktanata) zemljišta zagađenog mazutom. Niska obilnost normalnih alkana u frakciji ukupnih zasićenih alkana u početnom uzorku (identifikacija je bila mogućna tek nakon koncentrovanja pomoću karbamida) pokazala je da je ispitivani naftni zagađivač na granici između trećeg i četvrtog stupnja biodegradacije. Tokom eksperimenta, intenzivnu razgradnju fenantrena i njegovih metil, dimetil i trimetil izomera nije pratilo uklanjanje ostatka normalnih alkana. Njihova obilnost je ostala na početnom, niskom nivou i na kraju eksperimenta kada je zagađivač dostigao jedan od najviših stepena biodegradacije. Dobijeni rezultati su pokazali da se razgradnja pojedinih ugljovodonika uprkos njihovoj visokoj biodegradabilnosti ne odigrava do potpunog kraja ni u završnim fazama degradacije. U uslovima njihove smanjene dostupnosti, mikroorganizmi se opredeljuju za teže degradabilne, ali dostupnije ugljovodonike.

A reliable model for the prediction of the heat of vaporization for n-alkanes at 298.15 K with the number of carbon atoms and normal boiling point as the only input parameters is recommended. The new model is compared with other literature models and was found to give the best results with absolute mean percentage deviation of 0.81 % and maximum absolute percentage deviation of 2.93 %., U ovom radu predložen je pouzdan model za procenu vrednosti toplote isparavanja n-alkana na temperaturi 298,15 K sa brojem ugljenikovih atoma i normalnom temperaturom ključanja, kao jedinim potrebnim vrednostima. Predloženi model upoređen je sa postojećim odgovarajućim modelima i dao je najbolje, kako srednje procentualno odstupanje 0,81 %, tako i najmanju vrednost maksimalnog procentualnog odstupanja 2,93 %.

This is the first report of n-alkanes in needle epicuticular waxes of the variety Bosnian pine, Pinus heldreichii var. pančići. n-Hexane extracts of needle samples, originating from seven isolated localities in Serbia, were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The results evidenced n-alkanes ranging from C18 to C33 in epicuticular waxes. The most abundant alkanes were C27, C23, C25 and C29 (12.53 %, 12.46 %, 12.00 % and 10.38 % on average, respectively). The carbon preference index (CPItotal) of Pinus heldreichii var. pančići ranged from 1.1 to 2.1 (1.6 on average), while the average chain length (ACLtotal) ranged from 25.0 to 25.8 (25.3 on average). A high level of individual quantitative variation in all of these hydrocarbon parameters was also found. The obtained results were compared with the bibliographic references for Pinus heldreichii var. leucodermis and other species of the Pinus genus., Ovo je prvo saopštenje o n-alkanima u voskovima iglica varijeteta munike, Pinus heldreichii var. pančići. n-Heksanski ekstrakti uzoraka iglica koji potiču sa sedam izolovanih lokaliteta u Srbiji analizirani su gasnom hromatografijom (GC) i gasnom hromatografijom-masenom spektrometrijom (GC-MS). Rezultati su pokazali da se n-alkani nalaze u opsegu od C18 do C33. Među njima su najobilniji C27, C23, C25 i C29 (12,53, 12,46, 12,00 i 10,38 % u proseku, redom). Ugljenični preferencijalni indeks (CPItotal) Pinus heldreichii var. pančići je bio u opsegu od 1,1 do 2,1 (prosečno 1,6), a dužina niza ugljenikovih atoma (ACLtotal) u opsegu od 25,0 do 25,8 (prosečno 25,3). Takođe je utvrđen visok nivo individualne kvantitativne varijabilnosti u svim analiziranim parametrima ovih ugljovodonika. Dobijeni rezultati su upoređeni sa literaturnim podacima koji se odnose na Pinus heldreichii var. leucodermis i druge vrste roda Pinus.

The influence of the intensity of interaction between oil pollutants and ground waters in alluvial sediments on the effect of microbial activity was investigated in this work. The study was based on a comparison of detailed analyses of two fractions of an oil pollutant originating from a Danube alluvial formation near the Pancevo Oil Refinery: fraction 1. separated from the aqueous layer by decantation. presumed to have been in less intensive interaction with water. and fraction 2. isolated from the aqueous emulsion by extraction with chloroform. presumed to have been in stronger interaction with water, Both fractions were shown to originate from the same type of oil pollutant. Nevertheless. significant compositional differences between the two fractions were observed. A significantly pronounced domination of even carbon number homologues of C-18-C-24 n-alkanes in fraction 2. atypical for crude oil pollutants, compared to the corresponding distribution observed in fraction 1, suggested a more intense activity. i.e., a much better effect of microorganisms in direct contact with the oil pollutant within the aqueous environment. The identification of even carbon number C-14-C-18 n-alcohols and C-14-C-18 fatty acids, as well as cholesterol, in fraction 2, suggested that microorganisms of the algal type in non-photosynthetic conditions were most probably responsible for the mentioned microbial processes., Procenjivan je uticaj intenziteta interakcije između naftnog zagađivača i podzemne vode aluvijalne formacije na intenzitet mikrobiološkog dejstva. U tom cilju poređani su sastavi dve frakcije naftnog zagađivača iz jednog pijezometra (krug Rafinerije nafte Pančevo, aluvijalna formacija reke Dunav): frakcije 1, odvojene od vode dekantovanjem (slabija interakcija sa vodom) i frakcije 2, izdvojene iz vode ekstrakcijom (jača interakcija sa vodom). Dokazano je da obe frakcije vode poreklo od istog naftnog zagađivača. Znatno veća obilnost normalnih alkana sa izrazitom dominacijom parnih homologa (C18–C24) u frakciji 2 nego u frakciji 1 ukazuje na intenzivniju aktivnost mikroorganizama u vodenoj sredini. Alkoholi normalnog niza sa parnim brojem ugljenikovih atoma (C14–C20), holesterol i masne kiseline normalnog niza sa parnim brojem ugljenikovih atoma (C14–C18) u frakciji 2 dokaz su da su za mikrobilošku aktivnost u nefotosintetičkim uslovima odgovorni mikroorganizmi algalnog tipa.

The influence of the intensity of interaction between oil pollutants and ground waters in alluvial sediments on the effect of microbial activity was investigated in this work. The study was based on a comparison of detailed analyses of two fractions of an oil pollutant originating from a Danube alluvial formation near the Pancevo Oil Refinery: fraction 1. separated from the aqueous layer by decantation. presumed to have been in less intensive interaction with water. and fraction 2. isolated from the aqueous emulsion by extraction with chloroform. presumed to have been in stronger interaction with water, Both fractions were shown to originate from the same type of oil pollutant. Nevertheless. significant compositional differences between the two fractions were observed. A significantly pronounced domination of even carbon number homologues of C-18-C-24 n-alkanes in fraction 2. atypical for crude oil pollutants, compared to the corresponding distribution observed in fraction 1, suggested a more intense activity. i.e., a much better effect of microorganisms in direct contact with the oil pollutant within the aqueous environment. The identification of even carbon number C-14-C-18 n-alcohols and C-14-C-18 fatty acids, as well as cholesterol, in fraction 2, suggested that microorganisms of the algal type in non-photosynthetic conditions were most probably responsible for the mentioned microbial processes., Procenjivan je uticaj intenziteta interakcije između naftnog zagađivača i podzemne vode aluvijalne formacije na intenzitet mikrobiološkog dejstva. U tom cilju poređani su sastavi dve frakcije naftnog zagađivača iz jednog pijezometra (krug Rafinerije nafte Pančevo, aluvijalna formacija reke Dunav): frakcije 1, odvojene od vode dekantovanjem (slabija interakcija sa vodom) i frakcije 2, izdvojene iz vode ekstrakcijom (jača interakcija sa vodom). Dokazano je da obe frakcije vode poreklo od istog naftnog zagađivača. Znatno veća obilnost normalnih alkana sa izrazitom dominacijom parnih homologa (C18–C24) u frakciji 2 nego u frakciji 1 ukazuje na intenzivniju aktivnost mikroorganizama u vodenoj sredini. Alkoholi normalnog niza sa parnim brojem ugljenikovih atoma (C14–C20), holesterol i masne kiseline normalnog niza sa parnim brojem ugljenikovih atoma (C14–C18) u frakciji 2 dokaz su da su za mikrobilošku aktivnost u nefotosintetičkim uslovima odgovorni mikroorganizmi algalnog tipa.

In order to gain insight into oil transformations which occur during migration, and to contribute to the elucidation of migration mechanisms in water-wet environments, the content and composition of heavy fuel oil from an accidental oil spill near the railway station of Ušće (Kraljevo) was determined in crushed rock samples from various depths and distances from the oil spill. The group composition (saturated hydrocarbons, aromates, NSO-compounds and residue) of heavy fuel oil extracts was determined. n-Alkanes and isoprenoid alkanes, pristane (Pr) and phytane (Phyt), in the saturated hydrocarbon fraction were identified by gas chromatography (GC). X-ray diffraction analysis (XRD) was applied on the inorganic residue in order to determine its mineralogical composition. The observed differences in the group composition (increase in NSO-compounds content with depth and distance), and in the distribution of n-alkanes and isoprenoid alkanes (the shift of the n-alkane-maximum and the shift of Pr/n-C17-and Phyt/n-C18-ratios towards higher values with depth and distance) lead to the conclusion that heavy fuel oil migration through the crushed rock environment occurred in the presence of water by the colloidal micelle mechanism.