Brenda Basile

Polycyclic aromatic hydrocarbons in the Murchison meteorite

Abstract More than thirty polycyclic aromatic hydrocarbons, including nine heterocyclic aromatic compounds, have been identified in solvent extracts of the Murchison meteorite by gas chromatography-mass spectrometry using bonded-phase fused silica columns. Structural isomers of several alkylated aromatic hydrocarbons, including methylpyrene and methylphenanthrene were chromatographically separated, thus allowing calculations of the amount of alkyl substituted compounds in the solvent extracts. The ratio of odd-carbon number to even-carbon number was found to be approximately 0.1. Based on these data and literature data from model pyrolysis experiments, a temperature of 1000°C is suggested for the formation of polycyclic aromatic hydrocarbons in the solar nebula or premeteoritic body. The value of 1000°C is within the range of temperatures for the condensation of the nebular material from the initial high temperature phases to the lower temperature phases at which chemical and isotopic equilibria were frozen. A simple model for the abiotic synthesis of heterocyclic compounds from simple aliphatic precursors is also presented.

Deuteriated Analogs as Internal Standards for the Quantitation of Environmental Alkanes by Gas Chromatography

Abstract Quantitation by gas chromatography requires the use of suitable internal standards. Deuteriated analogs are superior, but usually require a mass spectrometer as the gas chromatographic detector to distinguish them from the compounds being measured. Completely deuteriated alkanes are, however, completely separated from the corresponding unlabelled alkanes and serve as suitable internal standards for the quantitation of environmental alkanes by gas chromatography alone.

Environmental effects of offshore oil production: Alkanes in the region of the Buccaneer oilfield

Abstract n -Alkanes, pristane, and phytane are among the hydrocarbons in discharged brine from production platforms in the Buccaneer oilfield. These compounds are detected in surface seawater samples, but hydrocarbons in bottom water samples are apparently of bacterial origin. Petroleum alkanes are also found in shrimp, fish, barnacles, plankton, and sediments.

Discharge of alkanes during offshore oil production in the buccaneer oilfield

ConclusionsWe have characterized the alkane content of the discharged brine from both production platforms in the Buccaneer oilfield over a period of eleven months, from April, 1976 to March, 1977. The mean concentration of C12-C36 alkanes was approximately 2 ppm (2 mg/l). The mean rate of discharge of brine in the field is approximately 600 bbl (95,400 l) per day. The mean rate of discharge of alkanes per day, therefore, is 191 g. Additional research is required to determine the rate of dispersion of these alkanes, their pool size in the vicinity of the production platforms, and their significance relative to alkanes of biogenic origin.

Alkanes in seawater in the vicinity of the buccaneer oilfield

ConclusionsConcentrations of alkanes in 76 water samples collected within 30 km of the Buccaneer oilfield between June, 1976, and March, 1977, were found to be as high as 43 ppb. It appears that petroleum alkanes discharged from the production platforms float at the air/sea interface and are dispersed. Further studies are required to determine their rates of dispersion and to investigate whether oxidation, metabolism, and other processes have a significant role in the removal of petroleum from the region of this oilfield. It seems likely that discharge from the production platforms of hydrocarbon-producing bacteria, or a nutrient which supports such bacteria, is responsible for the presence of bacterial hydrocarbons in bottom water samples down-current of the oilfield.BARBIERet al. (1973) found alkane concentrations of 2–28 ppb in the eastern Atlantic Ocean. A concentration maximum at C27 to C30 indicated that these compounds derived from phytoplankton (BLUMER 1970). Levels of alkanes ranging from 0 to 75 ppb were found by ILIFFE and CALDER (1974) in the Gulf of Mexico and the Caribbean Sea. Most of these were C15 to C20 alkanes of petroleum origin, but others in the range C21 to C36 were observed. BROWN and HUFFMAN (1976) have reported that the mean concentration of alkanes at several locations in the Atlantic, Arctic, and Indian Oceans, the Mediterranean Sea, and the Persian Gulf is 4 ppb. It was concluded that most of the compounds were petroleum-derived.Our data, by comparison with other reports in the literature, indicate that oil production in the Buccaneer field does not afford significant levels of alkanes in the surrounding seawater.

Alkanes in plankton from the Buccaneer Oilfield.

ConclusionsBLUMERet al. (1963, 1964) have reported the presence of pristane in relatively high concentrations in several copepods and have suggested that this compound has a role in the maintenance of buoyancy by these organisms. A number of unsaturated hydrocarbons have also been reported in Zooplankton (BLUMER and THOMAS 1965, BLUMERet al. 1970). The major n-alkane in a sample of mixed Zooplankton and phytoplankton from Tarpaulin Cove, Massachusetts was n-heptadecane, and lower concentrations of other C14 to C29 n-alkanes were found (CLARK and BLUMER 1967).We have found pristane and other biogenic alkanes in each sample examined. The presence of large amounts of C18 to C37 alkanes in sample XIV is believed to be good evidence for petroleum contamination (MIDDLEDITCHet al. 1977). A similar distribution of alkanes is observed in several other samples.In summary, one (XIV) of the nine samples from the center of oilfield was heavily contaminated with oil, two (XIII, XIV) were slightly contaminated, and another two (VI, VII) may have been contaminated. There is some evidence that two (V, XI) of the seven samples collected at distances of 10–15 km from the oilfield contained petroleum alkanes.Further work is required to determine which species of plankton preferentially ingest the oil and whether they have a role in the dispersion of oil discharged from the production platforms by (i) incorporation into fecal pellets which sink to the ocean floor, or (ii) transport away from the region of the oilfield.

Alkanes in surficial sediments from the region of the buccaneer oilfield

Abstract Surficials ** l ediment samples collected from below the production platforms in the Buccaneer oilfield contain up to 25 ppm of petroleum alkanes. On one occasion, concentration gradients of fresh oil were observed below both platforms, extending at least 75 ft. (22.9 m) from the platforms. On another occasion, the oil was more weathered and dispersed. There was no clear evidence for similar-profiIes in the vicinity of a well jacket structure, and alkanes in sediment samples collected at distances of 0.7-l 1 .O km from the production platforms were mostly of recent biogenic origin.

Alkanes in fish from the Buccaneer oilfield

ConclusionsThere was good evidence for petroleum alkanes in A.probatocephalus, C.spilopterus, C.arenarius, M.undulatus,P. saltatrix,P. porosissimus,P. rubio,S. brasiliensis,S. caprinus,S. papillosum,S. plagiusa,S. foetens, andU. floridanus. It was also possible thatA. felis,C. faber, andO. pardus were contaminated, but there were no petroleum alkanes in the other nine species examined. Levels of petroleum alkanes were usually higher in livers than in muscle tissue.

Alkanes in benthic organisms from the Buccaneer oil field

ConclusionsAlkane profiles of 48 benthic organisms from the Buccaneer oil field are reported. Coral samples contained biogenic alkanes in the C22 to C32 region (Koons et al. 1965). Hydroid specimens exhibited similar profiles which were also ascribed a biogenic origin. Samples of one species of mollusc,Pleuroploea giganta, from the production and quarters platforms contained petroleum alkanes, while corresponding samples from the well jacket did not contain these compounds. Some specimens of another mollusc,Pteria colymbus, contained petroleum hydrocarbons, while there was no evidence for petroleum hydrocarbons in any of the other species examined:Arbacia unctulata,Chloeia viridis,Murex fulvescens,Pagurus floridanus, andFasciolaria hunteria.Molluscs have been shown to sequester petroleum hydrocarbons after long periods of exposure (Lee et al. 1972). In the present study, however, petroleum alkanes were found only inPleuroploea gigantea andPteria colymbus, but even in these organisms such hydrocarbons were generally present in concentrations lower than those of the biogenic hydrocarbons.

Discharge of elemental sulfur and its distribution in surficial sediments in the region of the buccaneer oil field

Abstract The concentration of elemental sulfur in the produced water effluent from production platforms in the Buccaneer oil field was determined. In 15 samples collected between June, 1977 and May, 1978 the mean sulfur content was 457 ppm (range: