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Surface sediments from the Cross River estuary were analyzed for the quantitative determination of aliphatic lipids such as n-alkanes, n-alkanones and unresolved complex mixtures (UCMs) of branched and cyclic hydrocarbons. The concentrations of the hydrocarbons, including pristane and phytane, were in the range of 0.02-16.84 mg kg-1 (mean 2.23 ± 2.25 mg kg-1 dry weight). The high standard deviations for the n-alkanes most likely reflect the variation in sediment grain size and differences in quantity and quality of organic matter source input. Carbon preference indices for the full range of n-alkanes varied from 0.81 and 4.0, indicating both biogenic and residual petroleum origins. Some samples exhibit odd-to-even carbon number predominances, indicating an input from terrestrial plant waxes and/or macrophytes, whereas even-to-odd carbon number predominances were observed for other samples and are linked to industrial and/or microbial origins. Different distributions and elution ranges of UCMs were also observed, suggesting varied levels of petroleum contamination. Utilization of the LHC/SHC (long/short) ratio, ranging from 0.21-7.49, assisted in the evaluation of dominant trends for terrestrial plant and/or macrophytederived versus phytoplankton-derived organic matter inputs; while the parameter, Paq, allowed discrimination of the origin of long-chain n-alkanes and the importance of macrophyte contributions to the river system. Series of n-alkan-2-ones ranging from C15 to C35, with concentrations between 0.10 and 5.62 mg kg-1 (mean 0.82 ± 0.44 mg kg-1 dry weight) were identified and are considered to have a common origin from direct incorporation of epicuticular plant waxes on the basis of the regularity in their CPI values (1.19-1.21, odd-to-even). Phytone is thought to be a photo-induced microbial oxidation product from incorporated phytol and/or of direct input from tropical higher plant waxes. [ABSTRACT FROM AUTHOR]

The identification of 5β-stanones and their 5α-stereoisomeric counterparts in extracts of sediments from the Cross River estuary was achieved by gas chromatography-mass spectrometry. The concentrations of the stanones varied between 0.02 and 3.89 mgkg-1 with an overall average of 0.9 mgkg-1. The highest concentrations were measured at the lower estuary, with 5β-stigmastan-3-one as maximum, and at the upper estuary a minimum value for 5α-cholestan-3-one. The elevated levels of 5β-stanones in sediments of the lower estuary may be attributed to the proximity of high human and animal populations and storm resuspension of sediments as a consequence of high tidal cycles. The geochemical ratio of 5β- cholestan-3-one/(5β-cholestan-3-one + 5α-cholestan-3-one) is in the range of 0.28- 0.83 and indicates pollution by urban sewage, while the ratio of 5β-cholestan-3-one/5β- stigmastan-3-one, with values ranging from 0.09 to 2.92 is a more diagnostic indicator of fecal pollution from ruminant husbandry in the region.. [ABSTRACT FROM AUTHOR]

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 ngm3, 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 0.84883 ngm3, with the content at the urban site 1.16.6 times higher than those for the suburban site. The seasonal variation of 18-PAH concentrations was as follows winter > autumn > spring > summer. About 6788 of the PAHs were associated with particles having an aerodynamic diameter 2.0 m. PAHs concentration diagnostic ratios reflect that the major source of fine particles is from fossil fuel utilization. [ABSTRACT FROM AUTHOR]

In order to evaluate hydrocarbon inputs to Crater Lake from anthropogenic and natural sources, samples of water, aerosol, surface slick and sediment were collected and analyzed by gas chromatography-mass spectrometry (GC-MS) for determination of their aliphatic and aromatic hydrocarbon concentrations and compositions. Results show that hydrocarbons originate from both natural (terrestrial plant waxes and algae) and anthropogenic (petroleum use) sources and are entering the lake through direct input and atmospheric transport. The concentrations of petroleum hydrocarbons range from low to undetectable. The distributions and abundances of n-alkanes, polycyclic aromatic hydrocarbons (PAH) and unresolved complex mixture (UCM) from petroleum are similar for all surface slick sampling sites. The estimated levels of PAH in surface slicks range from 7–9 ng/m2 which are low. Transport of petroleum-derived hydrocarbons from the lake surface has resulted in their presence in some sediments, particularly near the boat operations mooring (total petroleum HC = 1440 µg/kg, dry wt. compared to naturally derived n-alkanes, 240 µg/kg, dry wt.). The presence of biomarkers such as the tricyclic terpanes, hopanes and steranes in shallow sediments further confirms petroleum input from boat traffic. In the deep lake sediments, petroleum hydrocarbon concentrations were very low (16 µg/kg, dry wt.). Very low concentrations of PAH were detected in shallow sediments (17–40 µg/kg at 5 m depth near the boat operations) and deep sediments (3–15 µg/kg at 580 m depth). The individual PAH concentrations in sediments (µg/kg or ppb range) are at least three orders of magnitude less than reported threshold effects levels (mg/kg or ppm range, test amphipod Hyalella azteca). Therefore, no adverse effects are expected to occur in benthic biota exposed to these sediments. Boating activities are leaving a detectable level of petroleum in surface waters and lake sediments but these concentrations are very low. [ABSTRACT FROM AUTHOR]

Investigations of natural and engineered environmental systems require achieving a complete characterization and identification of contaminants of concern. However, the differentiation of lipid molecular markers (MMs) that originated from various sources is difficult when based simply on their chemical compositions. A comprehensive fractionation protocol of lipid MMs is thus needed for discriminating contamination sources using chemometric (i.e., mathematical and statistical) techniques. The lack of information about the environmental quality of the coastal environment of Alexandria (Egypt) and the impact of anthropogenic sources of pollution in the area have initiated research to study the different extractable lipid classes and MMs in both natural and engineered environmental systems. Samples representing the complexity of the analyzed Alexandria environment were analyzed qualitatively and quantitatively for their lipid classes. A chemometric approach for the interpretation of the lipid data is presented. This unique approach consists of analysis of variance (ANOVA), discriminant partial least squares (D-PLS), and regularized discriminant analysis (RDA). ANOVA was used to compare the relative magnitudes of sample site and type variances. A variable selection approach based on the PLS regression coefficients was proposed to identify the most important lipid classes with their MMs for the classification, and to improve the results. RDA used a regularized covariance matrix estimate for the conventional statistical discriminant analysis methods. The results in this analysis indicated that: (a) the D-PLS and RDA methods provide satisfactory classification of lipid classes, with RDA being slightly better, and (b) the variable selection strategy was able to improve the classification results, and to help identify the most important lipid classes and contaminant MMs for distinguishing and characterizing the environmental samples. [ABSTRACT FROM AUTHOR]

The presence of saccharides is being reported for aerosols taken in urban, rural, and marine locales. The commonly found primary saccharides area α and β-glucose, α- and β-fructose, sucrose, and mycose with lesser amounts of other monosaccharides. Saccharide polyols are also found in some airsheds and consist mainly of sorbitol, xylitol, mannitol, erythritol, and glycerol. In temperate climate areas these compounds increase from negligible concentrations in winter aerosols (usually dominated by levoglucosan and related anhydrosaccharides from biomass burning) to a maximum in late spring-summer, followed by a decrease to winter. The composition of the saccharide mixtures suggests soil and associated micro- biota as the source. Saccharide analyses of soils confirmed these compositions. Therefore, we propose resuspension of soil (also unpaved road dust) from agricultural activities as a major component of aerosol particles and the saccharides are the source specific tracers. In addition, the saccharides as well as the anhydrosaccharide derivatives from biomass burning are completely water soluble and thus contribute significantly to the total water-soluble mass of aerosols. [ABSTRACT FROM AUTHOR]

Residential wood combustion is an important contributor to ambient fine particle levels in the United States. About one-half to two-thirds of the residential wood combustion in the United States occurs in wood stoves as opposed to fireplaces. Thus, any differences between these two sources must be accounted for in chemical mass balance receptor models which attempt to determine the contribution of wood smoke sources to ambient fine particle samples. To fully characterize the fine particle emissions from wood stoves and compare the emissions profiles to those determined from previous fireplace experiments, a series of source tests were conducted on the burning of the most prevalent U.S. tree species in wood stoves. The catalyst-equipped wood stove chosen for these tests was operated under both noncatalytic and catalytic conditions to assess the effects of the catalyst on fine particle emissions. Analysis of the wood smoke includes fine particle mass emission factors, organic and elemental carbon content, ionic and elemental composition, and detailed organic speciation by GC/MS. Between 60 and 90% of the fine particle mass emissions were attributed to measured chemical species. The fine particle emissions from wood stoves show the same general patterns as those from the fireplace combustion of the same tree species; important differences between hardwood and softwood combustion are seen among the substituted phenols and diterpenoids, and levoglucosan is the most abundant individual organic compound emitted. However, fine particle mass emission factors from wood stoves are significantly lower than those from fireplaces. The elemental carbon content of the fine particle mass is generally higher in wood stove smoke than in fire- place smoke, and is even higher when the catalyst was employed. Furthermore, a greater fraction of the organic compounds is identifiable by GC/MS methods in the wood stove smoke vs. the fireplace smoke. These results suggest that differences in the source profiles between wood stove and fireplace combustion merit consideration in source apportionment calculations using organic compounds as tracers. [ABSTRACT FROM AUTHOR]

The resins bled from stems and in seed cones and leaves of Cryptomeria japonica, Glyptostrobus pensilis, Taxodium distichum, and T. mucronatum were characterized to provide an overview of their major natural product compositions. The total solvent extract solutions were analyzed as the free and derivatized products by gas chromatography-mass spectrometry to identify the compounds, which comprised minor mono- and sesquiterpenoids, and dominant di- and triterpenoids, plus aliphatic lipids (e.g., n-nonacosan-10-ol). Ferruginol, 7α-p-cymenylferruginol, and chamaecydin were the major characteristic markers for the Taxodioideae conifer subfamily. The mass spectrometric data can aid polar compound elucidation in environmental, geological, archeological, forensic and pharmaceutical studies. [ABSTRACT FROM AUTHOR]

The environmental fate of conifer resins and their natural product compounds as mixtures is of importance for source, alteration, and transport studies. The compound compositions of resins of the common Callitris species (Cupressaceae) based on gas chromatography-mass spectrometry have not been reported. Results show that diterpenoids were the most abundant components and callitrisic acid was present in the resin extracts of all Callitris species analyzed. Significant amounts of 4-epi-pimaric and sandaracopimaric acids, with lesser communic, ozic, and lambertianic acids, were also in the mixtures. Phenolic diterpenoids, for example, ferruginol, hinokiol, were found in trace quantities in some samples. Thus, callitrisic acid and 4-epi-pimaric acid are the characteristic diterpenoids of Callitris species that are amenable to molecular biomarker analyses in geological or environmental applications. [ABSTRACT FROM AUTHOR]