Total N-alkane Concentrations Research Articles

Laboratory scale bioremediation of petroleum-contaminated soil by indigenous microorganisms and added Pseudomonasaeruginosa strain Spet

The bioremediation of petroleum-contaminated soil was investigated at laboratory scale, using three different approaches. The first approach comprised biostimulation of indigenous microorganisms. The second approach involved combination of biostimulation of indigenous microorganisms and bioaugmentation by inoculation with free cells of petroleum degrading Pseudomonas aeruginosa strain Spet. The third was a variation of the second, in which inoculation with encapsulated cells in starch and sodium alginate of P. aeruginosa strain Spet was applied. The bioremediation of the original hydrocarbon-contaminated soil (3.5% dry weight) and that of diluted with clean natural soil at 1:1 w/w were investigated. By providing sufficient moisture, nutrients and aeration by stirring in the original contaminated soil, total concentration of n-alkanes was reduced by 94% after 191 days of treatment and total concentration of 16 polycyclic aromatic compounds by 79%, while for the 1:1 diluted soils biodegradation reached 89% and 79%, respectively. The results showed that bioaugmentation with free or encapsulated P. aeruginosa cells and/or soil dilution had no significant effect on biodegradation.

Polycyclic aromatic hydrocarbons and petroleum biomarkers in São Sebastião Channel, Brazil: Assessment of petroleum contamination

Polycyclic aromatic hydrocarbons (PAHs) and non-aromatic hydrocarbons (NAHs), including n-alkanes, isoprenoids and petroleum biomarkers (terpanes, hopanes, steranes and diasteranes), were quantified by gas chromatography with flame ionization and mass spectrometer detectors in sediment samples collected from the São Sebastião Channel (SSC), Brazil, where the largest Brazilian maritime petroleum terminal is located. The concentrations of total PAHs, total n-alkanes and petroleum biomarkers ranged from below the detection limits to 370 ng g −1, 28 μg g −1, 2200 ng g −1 (dry weight), respectively. The analysis of PAH distribution suggested combustion sources of PAHs as the main input for these compounds with smaller amount from petroleum contamination. The distribution of petroleum biomarkers undoubtedly demonstrated petroleum as a source of anthropogenic contamination throughout the region. The assessment of petrogenic sources of contamination in marine sediment is more challenging if only PAH analysis were carried out, which demonstrates that more stable hydrocarbons such as petroleum biomarkers are useful for investigating potential presence of petroleum.

Compositional characteristics of n-alkanes of the glaciers over the Tibetan Plateau and their environmental and climatic significances

We report on the concentration and compositional features of n-alkanes of natural and anthropogenic origins in the snow samples collected from the Qiyi glacier in the Qilian Mountains, the Yuzhufeng glacier in eastern Kunlun Mountains, the Xiaodongkemadi glacier in the Tanggula Mountains, and the Gurenhekou glacier in the Nyainqentanglha Range. The results indicate a decrease in the total n-alkane concentration (T-HCs) from the northeast to the south over the Tibetan Plateau. The T-HCs in these studied areas were close to those in the Belukha and Sofiyskiy glacier, Russian Alati Mountains and the Dasuopu glacier in the Himalaya but were much higher than those in the Greenland ice sheet, suggesting that the mountain glaciers in the Asian continent may receive a higher loading of n-alkanes than the Greenland ice core. Moreover, the compositional characteristics of n-alkanes indicated that the n-alkanes in the studied areas were probably originated from the plant waxes as well as the fossil-fuel combustion exhaust, whereas the contribution from the lower organisms was small. In addition, the plant wax (Cn(wax)) and anthropogenic (non-Cn(wax)) contributions revealed that fast industrialization may have significant effects on the organic pollutant composition in glacier over the Tibetan Plateau and its circumference environment. Particularly, except for the Yuzhufeng glacier, the ΣnC21−/ΣnC22+ and (nC15+nC17+nC19)/(nC27+nC29+nC31) ratio decreased from the Qiyi glacier to the Gurenhekou glacier over the Tibetan Plateau, while the carbon preference index (CPI) values increased. These results indicate a decrease in terrigenous input while an increase in marine input from the northeast to the south over the Tibetan Plateau. These two ratios can be used as the climatic and environmental change indicators.

Origins of n-alkanes, carbonyl compounds and molecular biomarkers in atmospheric fine and coarse particles of Athens, Greece

The abundance and origin of aliphatic hydrocarbons, carbonyl compounds and molecular biomarkers found in the aliphatic fraction of PM 10-2.5 and PM 2.5 in the centre of Athens Greece are discussed in an attempt to reveal seasonal air pollution characteristics of the conurbation. Each extract was fractionated into individual compound classes and was analyzed using gas chromatography coupled to mass spectrometry. Normal alkanes, ranging from C 14 to C 35, were abundant in PM 10-2.5 and PM 2.5 samples during both sampling campaigns. The daily concentration of total n-alkanes was up to 438 ng m − 3 for PM 10-2.5 and up to 511 ng m − 3 for PM 2.5. Additionally, gaseous concentrations of n-alkanes were calculated, revealing that the relative proportions between gaseous and particle phases of individual compounds may differ significantly between summer and late winter. Normal alkanals and alkan-2-ones were only detected in the fine fraction of particulate matter and their concentrations were much lower than the n-alkane concentrations. Several geochemical parameters were used to qualitatively reconcile the sources of organic aerosol. The carbon preference index (CPI) of the coarse particles in August had the highest value, while in March the leaf wax contribution decreased significantly and the CPI value was very close to unity for both sites. Maximum concentrations of carbonyl compounds were reported in the range of C 15–C 20, demonstrating that they were formed from anthropogenic activity or from atmospheric oxidative processes. 6, 10, 14-trimethylpentadecan-2-one, a marker of biogenic input, was also detected in our samples. Molecular biomarker compounds confirmed that ca. 60% of the aliphatic fraction on the sampled atmospheric particles originated from petroleum and not from any contemporary biogenic sources. Pristane and phytane were detected in the fine fraction with their presence indicating sources of fossil fuel in the range of C 16–C 20. At all sites the 17α(Η),21β(Η) hopane series was the most abundant hopane group.

Distributions and sources of bulk organic matter and aliphatic hydrocarbons in surface sediments of the Bohai Sea, China

Surface sediment samples from a matrix of fifty-five sites covering virtually the entire Bohai Sea (Bohai), China were analyzed for total organic carbon (TOC), total nitrogen (TN), n-alkanes, unresolved complex mixture (UCM), biomarkers and stable carbon isotopic composition ( δ 13C), and principal component analysis was performed for source identification of organic matter (OM). The distribution of organic carbon correlated well with sediment grain size with the finest sediments having the highest concentration, suggesting the influence of hydrodynamics on the accumulation of sedimentary organic matter (SOM). The corrected TOC/ON (organic nitrogen) ratios and δ 13C indicated mixed marine and terrestrial sources of SOM. Results suggested that δ 13C could be used as a potential indicator to observe the dispersion of Huanghe-derived sediments in Bohai. Total n-alkane concentrations varied over 10-fold from 0.39 to 4.94 μg g − 1 (dry weight) with the maximum terrigenous/aquatic alkane ratio observed at the Huanghe River Estuary (HRE) due to more higher plant OM from riverine inputs. C 12–C 22 n-alkanes with even-to-odd predominance were observed in several central-eastern Bohai sites. The HRE and its adjacent area is the main sink for the Huanghe river-derived OC. The ubiquitous presence of UCM, biomarkers (hopanes and steranes) and PCA results indicated the presence of petroleum contamination in Bohai, mainly from offshore oil exploration, discharge of pollutants from rivers, shipping activities and atmospheric deposition.

Distribution and sources of solvent extractable organic compounds in PM2.5 during 2007 Chinese Spring Festival in Beijing

The solvent extractable organic compounds (SEOC), including n-alkanes, polycylic aromatic hydrocarbons, fatty acids, and dicarboxylic acids in PM2.5 during the 2007 Chinese Spring Festival in Beijing, were measured via gas chromatography-mass spectrometry for determining the characteristics and sources of these organic pollutants. The concentrations of total n-alkanes, PAHs, and organic acids before Chinese Spring Festival Eve (1025.5, 95.9, and 543.3 ng/m3, respectively) were higher than those after (536.6, 58.9, and 331.8 ng/m3, respectively). n-Aalkanes and PAHs had much higher concentration in nighttime than those in daytime because of high relative humidity and low wind speed during the night. Combustion of coal and exhaust emission were major sources of n-alkanes. It could be concluded by the characteristic ratios that the primary source of PAHs in fine particles was the combustion of coal, but the combustion of gasoline was in the next place. The ratios of C18:0/C16 indicated the contribution of vehicular emissions to the fatty acids. Dicarboxylic and aromatic acids were abundant in daytime than in nighttime because these acids were secondary organic acid and the photochemical degradation of aromatic hydrocarbons was the main source.

Sources of organic matter in a coastal marine environment: Evidence from n-alkanes and their δ 13C distributions in the Hauraki Gulf, New Zealand

The distribution and δ 13C composition of sedimentary n-alkanes (C 14–C 34) were investigated to determine the origins of organic matter in surface sediments in a subtropical, non-riverine dominated coastal shelf. Core-top sediments were collected in the Hauraki Gulf, New Zealand, from three nearshore sites and four offshore sites that represent a range of depths and distances to land. Total n-alkane concentrations varied 2-fold ranging from 326 to 819 μg g − 1 and n-alkane δ 13C ranged from − 21.2‰ to − 38.9‰. Source apportionment was calculated using marine and terrestrial end-member values for n-alkane chain lengths and isotopic composition to derive an inventory of marine versus terrestrial organic matter. Using this multi proxy approach, marine inputs were shown to be relatively constant across the Hauraki Gulf. In contrast, concentrations of terrestrial n-alkanes varied 4-fold across the study sites. Terrestrial contributions were 56–65% of total n-alkanes, dominating at all but those sites most remote from land where terrestrial n-alkanes levels still comprised ~ 40–45% of the characterized organic matter. Bulk analyses (e.g. δ 13C of total organic carbon and C/N ratios) poorly resolved terrestrial inputs in this complex coastal environment. The success of the multi-proxy approach in identifying terrestrial input is attributed to the ability to resolve inputs from coastal sources of organic matter such as mangroves and sea grasses that can mask terrestrial sources. Organic carbon accumulation rates were relatively constant on the shelf (4.0 to 4.5 mg cm − 2 year − 1), highest at a deeper site on the outer shelf (10.7 mg cm − 2 year − 1), and lowest on the upper slope (3.2 mg cm − 2 year − 1). Alkane accumulation rates (19 to 140 μg cm − 2 year − 1) were more variable, with burial rates of terrestrial alkanes on the shelf averaging 1.5 times that of marine accumulation rates. The isotopic and biomarker data indicate that even in what is considered a marine-dominated coastal environment, an appreciable amount of terrestrial organic matter is readily transported from its locus of input across the shelf to be buried in outer-shelf depocenters.

Methyl ketones in high altitude Ecuadorian Andosols confirm excellent conservation of plant-specific n-alkane patterns

To reconstruct past shifts in the upper forest line (UFL) in the Northern Ecuadorian Andes we are studying the applicability of plant-specific patterns of lipids preserved in soils as proxies for past vegetation along an altitudinal transect. Longer chain length n-alkanes, (C19–C35) were previously found to occur in plant-specific patterns in the dominant vegetation in the area as well as in preliminary soil samples, and may serve as such a proxy. In the present study, we assessed the preservation of n-alkane patterns with depth in soils from five excavations along an altitudinal transect 3500–3860m above sea level (m.a.s.l) in the area. We used the carbon preference index (CPI) as well as chain length distributions of n-alkanes and their most likely degradation products, n-methyl (Me) ketones, n-alcohols and n-fatty acids. Clear n-alkane patterns were found in all the soils and at all depths, while a clear relationship with the observed patterns of n-Me ketones identified them as the primary degradation product of the former. Very low average n-Me ketone/n-alkane ratio values were found, ranging from 0.03 to 0.15 at the top of the mineral soil, to 0.05–0.20 at the interface with an underlying palaeosol several thousand years old. The concurrent high CPI values indicate very limited degradation of n-alkanes with depth. Except for C33, the shifts in n-Me ketone/n-alkane values were similar for all chain lengths investigated, signifying an absence of preferential degradation of individual n-alkanes. With one exception, all the soils showed a similar increase in n-Me ketone/n-alkane values with depth, indicating that the degradation rates were not influenced by altitude. This means that, even if the total concentration of n-alkanes decreases over time, the characteristic pattern remains intact, conserving their potential as a biomarker for past vegetation reconstruction in the area, as well as for investigation of degradation processes of soil organic carbon.

Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze River) estuarine and East China Sea shelf sediments

To examine the source and preservation of organic matter in the shelf sediments of the East China Sea (ECS), we measured bulk C/N and isotopes, organic biomarkers (n-alkanes and fatty acids) and compound-specific (fatty acids) stable carbon isotope ratios in three sediment cores collected from two sites near the Changjiang Estuary and one in the ECS shelf. Contrasting chemical and isotopic compositions of organic matter were observed between the estuarine and shelf sediments. The concentrations of total n-alkanes and fatty acids in the shelf surface sediments (0–2 cm) were 5–10 times higher than those in estuarine surface sediments but they all decreased rapidly to comparable levels below the surface layer. The compositions of n-alkanes in the estuarine sediments were dominated by C26-C33 long-chain n-alkanes with a strong odd-to-even carbon number predominance. In contrast, the composition of n-alkanes in the shelf sediment was dominated by nC15 to nC22 compounds. Long-chain (>C20) fatty acids (terrestrial biomarkers) accounted for a significantly higher fraction in the estuarine sediments compared to that in the shelf sediment, while short-chain (<C20) saturated and unsaturated fatty acids were more abundant in the shelf surface sediments than in the estuarine sediments. Stable carbon isotopic ratios of individual fatty acids showed a general positive shift from estuarine to shelf sediments, consistent with the variations in bulk δ 13CTOCTOC. These contrasts between the estuarine and shelf sediments indicate that terrestrial organic matter was mainly deposited within the Changjiang Estuary and inner shelf of ECS. Post-depositional diagenetic processes in the surface sediments rapidly altered the chemical compositions and control the preservation of organic matter in the region.

Sources and Seasonal Changes in the Distributions of Aliphatic and Polycyclic Aromatic Hydrocarbons in Size Fractions of Atmospheric Particles of Beijing, China

Five-stage size-segregated ambient aerosol particles were collected during January 2003 until October 2004 at one urban and one suburban site of Beijing to investigate the seasonal size distributions of aliphatic and polycyclic aromatic hydrocarbons. The concentrations of total n-alkanes ranging from C11 to C35 varied between 2.1 and 2446 ng/m3, with higher values at the urban site than suburban site. A seasonal fluctuation was clearly evident, with higher concentrations occurring during the colder period. The carbon preference index (CPI) of the n-alkanes displayed the highest values in the spring and apparently decreased in winter. Furthermore, smaller size airborne particle-bound n-alkanes tend to have lower CPI values. In addition, the presence of pristane, phytane, n-alkylcyclohexanes, hopanes, and steranes, together with the major unresolved complex mixture (UCM) of branched and cyclic compounds, confirmed the contribution from fossil fuel use in ambient aerosol particles of Beijing. The concentrations of 18 unsubstituted PAHs (∑18-PAH) varied from 0.84–883 ng/m3, with the content at the urban site 1.1–6.6 times higher than those for the suburban site. The seasonal variation of ∑18-PAH concentrations was as follows: winter > autumn > spring > summer. About 67–88% of the PAHs were associated with particles having an aerodynamic diameter ≤2.0 μm. PAHs concentration diagnostic ratios reflect that the major source of fine particles is from fossil fuel utilization.

Spatial and diurnal distributions of n-alkanes and n-alkan-2-ones on PM 2.5 aerosols in the Lower Fraser Valley, Canada

Ninety daytime/nighttime PM 2.5 aerosol samples were collected at 5 sites in forest, tunnel, urban, rural, and mixed forest/urban areas in the Lower Fraser Valley during the Pacific 2001 Air Quality Study. Solvent-extractable organic matter, such as n-alkanes (C 14–C 33), n-alkan-2-ones (C 10–C 31), and 6, 10, 14- trimethylpentadecan-2-one on the fine aerosols, were quantified. The concentrations of total n-alkanes from primary sources were 45.5–112 ng m −3 at the tunnel site, 3.3–34.6 ng m −3 at the urban site, 0.6–18.1 ng m −3 at the rural site, and 1.7–16.9 ng m −3 at the forest and the mixed areas. The homologue distributions of the n-alkanes displayed different patterns at the 5 sites, showing day–night differences and reflecting their primary source types and impacts of episodes. The carbon preference index (CPI) values of the n-alkanes showed highest value (average of 2.39±0.47) at the forest, lowest (1.15±0.11) at the tunnel. The CPI showed higher values in night samples at all sites except the urban site which was impacted by specific episodes such as biomass burning and/or fuel burning occurring during the nighttimes, the higher nighttime values of CPI, with consistent lower n-alkane concentrations, suggested that weaker anthropogenic emissions during night were a more likely cause . The total n-alkan-2-ones on the aerosols were 1.8–12.6 ng m −3 at the tunnel site and 0.2–7.2 ng m −3 at the other 4 sites. Low-molecular weight n-alkan-2-ones (<C 22) were observed at all sites with the highest level at the tunnel. High molecular weight n-alkan-2-one (>C 23) were consistently higher at the tunnel but varied with date at the forest site. The n-alkan-2-ones, both low and high molecular weight, could have multiple sources including vehicular emissions and oxidation processes. The branched ketone, 6, 10, 14- trimethylpentadecan-2-one, an oxidative product of phytol on the fine aerosols, was enriched in the forest with the average of 7.6±7.1 ng m −3.

Uso de N-alcanos na estimativa da composição botânica em amostras com diferentes proporções de Brachiaria brizantha e Arachis pintoi

Este trabalho foi conduzido para se determinar a composição de n-alcanos (C24 a C36) em diferentes proporções de dietas hipotéticas de Brachiaria brizantha Stapf. cv. Marandu e Arachis pintoi Koprov &amp; Gregory. cv. Amarillo (0; 15; 30; 45; 60 e 100% de Arachis pintoi) e identificar a combinação de alcanos que permite calcular a composição botânica de dietas com o menor valor residual (real menos o estimado). As forragens foram amostradas no verão e os n-alcanos extraídos pelo método de saponificação direta, sendo identificados e quantificados por meio de análise de cromatografia gasosa. O alcano C34 foi utilizado como padrão interno. As proporções de A. pintoi nas dietas foram estimadas pela minimização do z (soma dos quadrados dos desvios) entre a proporção real dos alcanos analisados e as proporções pré-estabelecidas (tratamentos), utilizando-se a equação de Duncan et al. (1999). Observou-se que houve predomínio das cadeias carbônicas ímpares e que a concentração total de n-alcanos decresceu à medida que se aumentou a proporção de A. pintoi nos tratamentos. Estimativas acuradas da composição botânica de misturas de A. pintoi com B. brizantha foram obtidas utilizando-se os alcanos C29, C31, C33 e C35. O alcano C35 foi fundamental para a qualidade das estimativas. Os resultados indicaram o grande potencial da técnica para estudos com animais em pastejo.

Comparison of purge and trap GC/MS and spectrophotometry for monitoring petroleum hydrocarbon degradation in oilfield produced waters

Results of using a field spectrophotometer and its appropriate protocols as a surrogate method for an oilfield produced water treatment process is presented. Methylene chloride extractions of the produced water before and after treatment maintained a yellow color pigment that was directly proportional to the hydrocarbon concentration. From this, an absorption spectrum and standard curve were developed. A resultant linear plot of the standard curve indicated that there is an excellent correlation ( r 2=0.9847) between the varying concentrations and the associated absorbance values at a wavelength of 400 nm. Total n-alkane concentration comparisons between the laboratory GC/MS analysis and the spectrophotometry analysis generated data of similar accuracy and precision at concentrations ranging from 1 to 137 mg/l (alpha=0.05). Linear comparisons between GC/MS and spectrophotometric coefficients were near unity, with the constant being near zero, with a correlation coefficient ( r 2) of 0.99. Based on this study, spectrophotometry is a complimentary method to GC/MS for determining total n-alkane concentrations in oilfield produced water samples.

Aliphatic and polycyclic aromatic hydrocarbons in sediments of Kaohsiung Harbour and adjacent coast, Taiwan

Surficial sediment samples collected from Kaohsiung Harbour and its nearby coast were analyzed for aliphatic hydrocarbons and parent polycyclic aromatic hydrocarbons (PAHs). According to our results, the average total concentrations of n-alkanes (n-C12 to C35) and aromatics (15 PAHs) were 4.33 microg g(-1) dry weight (ranged 0.46-22.60) and 0.59 microg g(-1) dry weight (ranged 0.09-1.75), respectively. The highest concentrations of aliphatic and aromatic hydrocarbons were recorded in stations near the estuaries of Qianzhen River and Love River, respectively. Aliphatic hydrocarbons in the samples indicate that there has been significant non-petrogenic, possibly terrestrial, contribution in the sediment of the open coast of Kaohsiung Harbour and that there has been dominant contribution from petrogenic sources in the sediment of the inner harbour. PAHs, detected in the samples, however, indicated a higher pyrolytic contribution in open-coast samples and a higher petrogenic contribution in the inner harbour. Overall, sediment concentrations of total alkanes in this study were comparable to those found in Victoria Harbour, Hong Kong and are higher than those found in Xiamen Harbour, China. Concentrations of total PAHs in inner Kaohsiung Harbour sediments were relatively lower than those found in Victoria Harbour, Hong Kong and Xiamen Harbour, China, but comparable to those found in Hsin-ta Harbour, Taiwan and Incheon Harbour, Korea. In comparison with several effect-based sediment quality guidelines, most PAH concentrations found in samples taken from inner harbour stations exceeded the Threshold Effect Level of Florida indicating a slight possibility of adverse effects.

Abundance of Macroalgal Organic Matter in Biofilms: Evidence from n-Alkane Biomarkers

Biofilm development on titanium panels immersed in the surface waters of Dona Paula Bay was investigated using molecular biomarkers such as n-alkanes and other chemical and biological parameters. Biofilm biomass measured as organic carbon (OC), organic nitrogen (ON), chlorophyll a, diatoms and bacterial numbers on the titanium panels generally increased over the period of immersion. Total lipids and n-alkane concentration also showed similar trends. n-alkanes from C12 to C30 were detected in the biofilm samples, which showed a bimodal distribution. The first mode consisted of n-alkanes > C23 with a strong even over odd predominance. In the second mode, the n-alkanes < C23 were more abundant with odd carbon number maxima at C15, C17 and C19 and a strong odd over even carbon number predominance (Carbon Preference Index > 2). The predominance of these odd-chain n-alkanes strongly indicates that the organic matter derived from macroalgal sources was the major contributor to the biofilm organic matter developed on the titanium panels over the 15 d period of study. The data suggest that molecular characterization is a useful tool in understanding the sources of biofilm organic matter. The observed abundance of macroalgal organic matter during the 15 d period of biofilm development may play an important role in subsequent fouling by micro- and macrofouling organisms.

Characterization of n-alkanes in PM 2.5 of the Taipei aerosol

Ambient concentrations of n-alkanes with carbon number ranging from 17 to 36 were determined for PM 2.5 samples collected in Taipei city during September 1997–February 1998. The measured concentrations of particulate n-alkanes were in the range of 69–702 ng m −3, considerably higher than the concentration levels observed in Los Angeles and Hong Kong. The concentration distributions of n-alkanes homologues obtained in this study exhibited peaks at C 19, C 24 or C 25. This suggests that fossil fuel utilization, such as vehicular exhaust and lubricant residues, was an important contributor to the Taipei aerosol. Source apportionment of PM 2.5 was conducted using carbon preference index (CPI, defined as the ratio of the total concentration of particulate n-alkanes with odd carbon number to that with even carbon number) and U : R ratio (the concentration ratio of unresolved components to resolved components obtained from chromatograms). The low CPI value (0.9–1.9) and high U : R ratio (2.6–6.4) for each sample further confirmed that fossil fuel utilization was the major source of n-alkanes in ambient PM 2.5 of Taipei city. Estimates from these results showed that 69–93% of the n-alkanes in PM 2.5 of the Taipei aerosol originated from vehicular exhaust. The higher concentration level of particulate n-alkanes in the Taipei aerosol was mainly a result of vehicular emissions.

Aliphatic and Aromatic Hydrocarbons in Sediments of Santos and Cananéia, SP, Brazil

Sediment samples from Santos and Cananéia, São Paulo Brazil were analysed by GC–FID and GC–MS for aliphatic and aromatic hydrocarbons in order to gather information on the degree of contamination by oil and other biogenic contributions. Concentrations of total n-alkanes in Santos varied from 1.05 to 4.29 μg g −1 and aromatic hydrocarbons from 0.08 to 42.39 μg g −1 . In Cananéia total n-alkanes varied from 4.37 to 157.90 μg g −1 . However, aromatic hydrocarbons were not detected. In Cananéia n-alkanes of terrestrial plants with high molecular weight predominate ( n-C 25, n-C 27, n-C 29, n-C 31 and n-C 33). In Santos, a more uniform distribution of the n-alkanes and aromatic hydrocarbons was found at all the sediment stations. The hydrocarbon data from stations close to the Saboó Wharf, at Alemoa and in the COSIPA Channel revealed alarming levels of acenaphthylene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene and chrysene.

Evidence for Organic Film on an Impervious Urban Surface: Characterization and Potential Teratogenic Effects

Chemical constituents of an organic film collected from an impervious urban surface, namely the exterior surface of windows, have been characterized. The organic portion of this film, that ranged in thickness from 11 to 100 nm, constitutes a previously unrecognized site for exchange of semivolatile organic contaminants in urban environments. The concentrations of total n-alkanes, total polycyclic aromatic compounds (PAH), and total polychlorinated biphenyls (PCB) ranged from 1010 to 22 500, 900 to 62 100, and 8 to 5820 ng/m2 of window surface, respectively. Whereas concentrations varied, the patterns of chemical and congener abundance were similar among samples. Alkanes were derived from mainly biogenic sources, while the PAH showed a weathered pattern and PCB congener patterns generally indicated an enrichment in higher chlorinated congeners. Film-to-air partition ratios, KFA, were calculated for selected PAH and PCB congeners and were comparable to reported values of octanol−air partition coefficients, KOA, suggesting that gas-phase compounds partition into this organic film. Potential biological effects of an organic film extract were evaluated using zebrafish embryo assays. Incubation at a concentration of 270 ppb ΣPAH plus 420 ppb ΣPCB showed 100% lethality, while concentrations 3−10 times lower produced a dose-dependent syndrome of abnormalities including cardiovascular, hematopoietic, neural crest-related, and behavioral defects.

Determination of n-alkanes and polycyclic aromatic hydrocarbons in atmospheric particulate and vapour phases in Oviedo, Spain, by GC-MS.

A GC-MS procedure for the determination of hydrocarbons in air samples from Oviedo, Spain, was developed. Air hydrocarbons were sampled with a high volume sampler equipped with a holder containing a glass fiber filter, to trap the particulate phase, and two polyurethane foams to capture hydrocarbons of the vapour phase. Compounds were extracted with CH2Cl2 by Soxhlet extraction and then fractionated using column chromatography with alumina silica. Analyses of the fractions were performed by GC-MS in the electron ionization mode. PAHs and n-alkanes were the compounds examined in this work. Samples collected in the vicinity of the Faculty of Chemistry (a semi-urban area) were analysed. The total concentration of PAHs in the air samples analysed ranged from 28 to 76 ng m(-3). The total concentration of n-alkanes and PAHs in the vapour phase exceeded the concentration in the particulate phase in the samples analysed.

Biogenic hydrocarbons in the particulate material of the water column of the Bellingshausen Sea, Antarctica, in the region of the marginal ice zone

The biogenic hydrocarbon content of particulate matter of the Bellingshausen Sea in the region of the marginal ice zone (MIZ) has been used to investigate the origins and fates of organic material in the water column in the region of a marginal ice zone. Particulates were sampled from four depths to 200 m in pack ice and at the ice edge, and from seven depths to 3000 m in open ocean. Total n-alkane concentrations associated with particulates increased from 200 ng l −1 under the pack ice to 1000 ng l −1 in the open ocean, and decreased with depth in open water to 15 ng l −1 at 3000 m. The influence of phytoplankton on particulate material was shown to be negligible under the ice but extended horizontally and vertically as the ice edge retreated. Sea-ice algae did not appear to seed the phytoplankton growth under the ice or the subsequent “bloom” at the MIZ. The alkane signature of phytoplankton from the MIZ bloom was detected at a depth of 200 m near the ice edge, at 500 m in open sea, and in surface sediments (4100 m). Zooplankton biomarkers that were at low levels in krill under the ice were higher in animals from the open ocean but were not detected in the water column or sediments. It was concluded that the majority of particulate material in the water column was algal in origin. Material in the surface sediment from under pack ice probably originated from a deep-living winter population of copepods and material in surface sediment from the ice-free ocean originated from the algal “bloom” at the MIZ.