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PubMed2004

Phytoremediation of petroleum hydrocarbons in tropical coastal soils. II. Microbial response to plant roots and contaminant.

GOAL, SCOPE AND BACKGROUND: The goal of this study was to understand the interaction between plants and microorganisms during petroleum-hydrocarbon bioremediation in Pacific Islands coastal soils. Total bacteria and hydrocarbon-degrading microorganisms population dyanamics were examined in the rhizospheres of tropical trees and shrubs, which were evaluated for their phytoremediation potential in a greenhouse experiment. The respective and combined effects of plant roots and diesel contaminant on the microbial populations were determined in relation to diesel fuel depletion. An increase in the grading populations size of the hydrocarbon-degrading populations of microbes, elicited by rhizodeposition, is generally regarded as conducive to an enhanced degradation of petroleum hydrocarbon pollutants in vegetated soil. METHODS: The soil was a coastal sandy loam (pH 7.8) which was artificially contaminated with 10 g of No. 2 diesel fuel/kg soil or left uncontaminated. The pots were irrigated with fertilizer and 1% NaCl. The enumerations were carried out in the contaminated and uncontaminated rhizospheres of three trees, kiawe (Prosopis pallida), milo (Thespesia populnea), and kou (Cordia subcordata) and three shrubs, beach naupaka (Scaevola sericea), false sandalwood (Myoporum sandwicense), and oleander (Nerium oleander). Unplanted control soils were included in the experiment. Total bacteria and phenanthrene-degrading bacteria were enumerated on plates. Diesel- and pristane-degrading microorganisms were enumerated by the most-probable-number technique in tissue-culture plates. RESULTS AND DISCUSSION: All four types of microorganisms responded to the rhizosphere of the 6 plants in uncontaminated soil and to the diesel contaminant in unplanted soil. In contaminated rhizospheres, no effect of the plant on the hydrocarbon-degrader numbers was visible. Total bacteria responded more to the plant roots than to the contaminant. The phenanthrene-degrading bacteria and pristane-degrading microorganisms were more influenced by the contaminant than by the plants. The diesel-degrading microorganisms were equally stimulated by the plants and the contaminant. The numbers of hydrocarbon degraders were similar in the contaminated rhizospheres of the three effective plants (kiawe, kou, and milo) and in those of the three ineffective shrubs. CONCLUSION: The results suggest the quality of the rhizodeposition is plant-dependent and governs the type of diesel-degrader populations that will be enhanced by a given plant. RECOMMENDATIONS AND OUTLOOK: In the proposed phytoremediation-benefit model plant roots maintain high levels of hydrocaron degraders in uncontaminated soil. When the root enters a contaminated zone of soil, those hydrocarbon degraders that prefer the contaminant would switch to the contaminant as a carbon source, effectively removing the hydrocarbons. If the root exudates and the contaminant are equally attractive to the hydrocarbon degraders, the contaminant degradaton would be less effective.

Biodegradation, Environmental↗
PubMed2005

Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products.

Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different 34S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured 34S/32S isotope ratio of the isotope-diluted sample remained constant-a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 microg g(-1) ('sulfur-free' premium gasoline) to 10.4 mg g(-1) (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 microg g(-1) and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level.

Lasers↗
PubMed2001

Bioremediation of sterile agricultural soils polluted with crude petroleum by application of the soil bacterium, Pseudomonas putida, with inorganic nutrient supplementations.

The effects of bioremediation program of sterile agricultural soils contaminated with crude petroleum were determined with a view to developing a suitable technique for rehabilitation of similar environments upon pollution by oil spillage. Sterile soils inoculated with the soil bacterium, Pseudomonas putida (PP), with inorganic nutrients monitoring and supplementation constituted the experimental set-ups (ESU). The control set-ups (CSU) contained all the materials present in ESU except that they were not inoculated with PP. In ESU at week 9, the oil pollutant was completely biodegraded, and the inorganic nutrient ions, particularly PO4(-3) and NO3(-1), were significantly utilized. In contrast, there were no significant changes in the concentrations of oil and inorganic nutrients in CSU. Also, the percentage germination and growth profiles of cress seeds (Lepidium sp.) planted as evidence of the recovery of the oil-impacted soils were poor in CSU (27.5%) with pronounced abnormal morphology when compared with the results obtained for ESU (98.8%). Inoculation of PP with addition of appropriate inorganic nutrients may be a suitable method for a rapid rehabilitation of agricultural land upon pollution with crude petroleum.

Biodegradation, Environmental↗
PubMed2003

Recombinant carbazole-degrading strains for enhanced petroleum processing.

Biotechnological upgrading of fossil fuels is of increasing interest as remaining stocks of petroleum show increasing levels of contaminants such as heavy metals, sulfur and nitrogen-containing heteroaromatic compounds. Carbazole is of particular interest as a major petroleum component known to reduce refining yields through catalyst poisoning. In this study, the biotransformation of carbazole was successfully demonstrated in a liquid two-phase system, when solubilized in either 1-methylnaphthalene or in diesel fuel. The effects of solvent toxicity were investigated by expressing the carbazole-transformation genes from MB1332, a rifampicin-resistant derivative of Pseudomonas sp. LD2, in a solvent-resistant heterologous host, P. putida Idaho [1]. This solvent-resistant strain successfully degraded carbazole solubilized in 1-methylnaphthalene and in the presence of 10 vol% xylenes similar to the non-recombinant strain Pseudomonas sp. LD2. Identification of a suitable recombinant host, however, was essential for further investigations of partial pathway transformations. Recombinant P. putida Idaho expressing only the initial dioxygenase enzymes transformed carbazole to an intermediate well retained in the oil phase. Partial carbazole transformation converts carbazole to non-aromatic species; their effect is unknown on refinery catalyst poisoning, but would allow almost complete retention of carbon content and fuel value.

Bacterial Proteins↗
PubMed2006

UV spectroscopic monitoring of vaporized monoaromatic hydrocarbons from petroleum-contaminated soils.

Fast and simple systems using ultraviolet (UV) absorbance were examined for on-line monitoring of monoaromatic hydrocarbons from petroleum-contaminated soils in this research. Since soil particles hinder the UV light transmittance, the absorbance measurement of vaporized monoaromatic hydrocarbons in soil gas extracted from petroleum-contaminated soils was proposed. In the fixed system that exhibited higher sensitivity than the portable one, the absorbance intensity of benzene, toluene, ethylbenzene, and xylene increased in proportion to the concentration of the contaminants. The portable system, however, was suitable for screening purpose, while it exhibited faster response. There was no interference from water, which helps the applicability of the proposed systems to the actual fields.

Environmental Monitoring↗
PubMed2006

Petroleum contaminated soil in Oman: evaluation of bioremediation treatment and potential for reuse in hot asphalt mix concrete.

This paper presents a study that aims at evaluating the leaching characteristics of petroleum contaminated soils as well as their application in hot mix asphalt concrete. Soil samples are environmentally characterized in terms of their total heavy metals and hydrocarbon compounds and leachability. The total petroleum hydrocarbon (TPH) present in the PCS before and after treatment was determined to be 6.8% and 5.3% by dry weight, indicating a reduction of 1% in the TPH of PCS due to the current treatment employed. Results of the total heavy metal analysis on soils indicate that the concentrations of heavy metals are lower when extraction of the soil samples is carried out using hexane in comparison to TCE. The results show that the clean soils present in the vicinity of contaminated sites contain heavy metals in the following decreasing order: nickel (Ni), followed by chromium (Cr), zinc (Zn), copper (Cu), lead (Pb), and vanadium (V). The current treatment practice employed for remediation of the contaminated soil reduces the concentrations of nickel and chromium, but increases the concentrations of all remaining heavy metals.

Biodegradation, Environmental↗
PubMed1995

Genetic effects of petroleum fuels: cytogenetic monitoring of gasoline station attendants.

Workers in the petroleum distribution trades experience relatively high-level exposures to fuel vapours whose consequences have not been fully elucidated. In this study, the possible relationship between occupational exposure to petroleum fuels and cytogenetic damages in peripheral lymphocytes was investigated. Twenty-three male, non-smoking workers from the area of Rome were enrolled in the study, together with age-paired controls with no occupational exposure to fuels. Peripheral lymphocyte cultures were set up for the analysis of structural chromosome aberrations (CAs), sister chromatid exchanges (SCEs) and micronuclei (MN) in cytokinesis-blocked lymphocytes. Frequencies of CAs, SCEs and MN were compared between exposed and control groups, and evaluated in relation to blood lead level (as an indicator of engine exhausts exposure) for the whole group under study, and to yearly averaged exposure to benzene (8-h time weighted averages, as determined by repeated personal sampling) for fillingstation attendants only. Both CAs and SCEs were slightly increased in station attendants: 1.97 versus 1.46 aberrations per 100 cells, and 4.73 +/- 0.15 versus 4.48 +/- 0.11 SCEs/cell in exposed and control individuals, respectively. The difference between cumulative CA rates in the exposed and control populations was of borderline statistical significance (p = 0.066). However, when the exposed population was dichotomized for benzene exposure, a significant (p = 0.018) correlation of CAs with benzene exposure was found. The analysis of SCE data highlighted a significant increase of cells with more than 6 exchanges (HFCs), corresponding to the 75 degrees percentile of the overall distribution, in fillingstation attendants (relative risk (RR) = 1.3, 95% CI = 1.1-1.5) in comparison with controls. In the pooled population, the frequency of HFCs showed a statistically significant upward trend at increasing blood lead levels (chi 2 for trend = 27.8, p < 0.0001). A complex relationship between SCEs and benzene exposure was observed, with an increased frequency of HFCs in the medium exposure intensity class (RR = 1.5, 95% CI = 1.2-1.7), and no difference for exposure to higher benzene levels (RR = 1.0, 95% CI = 0.9-1.2), compared to reference subjects. Finally, the analysis of MN in both phytohemagglutinin- and pokeweed-stimulated cell cultures did not show significant excess of MN in binucleated lymphocytes of exposed workers with respect to the age-paired controls.

Adult↗
PubMed1992

Identification of natural, anthropogenic and petroleum hydrocarbons in aquatic sediments.

Complex distributions of hydrocarbons occur in most aquatic sediments. Total concentrations can range from a few parts per million in non-polluted intertidal and oceanic areas to parts per thousand in heavily contaminated estuarine, lake and near-shore environments. Iatroscan TLC-FID provides a quick assessment of the total hydrocarbon load, but capillary GC, HPLC and GC-MS are essential for obtaining detailed composition data from which information on possible sources can be derived. Alkenes from microalgae, such as n-C21:6, n-C17:1 and unusual C25 and C30 isoprenoid alkenes, are often the most abundant single components in sedimentary hydrocarbon distributions. Some hydrocarbons are also produced from diagenetic transformation of functionalised lipids present in the sediment. Long-chain alkanes typical of plant waxes can be important constituents, even in marine sediments far from the coast. These distributions display a strong predominance of odd chain lengths, whereas n-alkane distributions in oils usually show little or no predominance of either odd or even chain lengths. However, the presence of this type of distribution in a sediment may not indicate petroleum contamination since biological sources for similar distributions are now recognised. Petroleum-derived residues are common in coastal and estuarine areas, particularly those near urban or industrial centers. This contamination is readily seen in capillary gas chromatograms of the alkanes as an unresolved complex mixture (UCM). The source of the oil can often be deduced from characteristic distributions of biomarker steranes, rearranged steranes, hopanes and methyl hopanes determined by capillary gas chromatography-mass spectrometry. Methyl hopanes are major polycyclic alkanes in oils from carbonate source rocks, such as those from the Middle East, but are uncommon in Australian oils. GC-MS fingerprinting techniques show that lubricating oils are a major source of hydrocarbon pollution in many estuaries and coastal areas around Australia. It has been estimated that natural oil seeps may also contribute as much as 10% of the hydrocarbons in the global marine environment. Examples of this include major oil seepage in the Gulf of California and the widespread occurrence of bitumen strandings on South Australian beaches. Examples from marine and estuarine environments around Australia are presented to illustrate the use of modern analytical techniques to identify, quantify and determine the origins of hydrocarbons in aquatic sediments.

Australia↗
PubMed1996

Phenols in hydrothermal petroleums and sediment bitumen from Guaymas Basin, Gulf of California.

The aliphatic, aromatic and polar (NSO) fractions of seabed petroleums and sediment bitumen extracts from the Guaymas Basin hydrothermal system have been analyzed by gas chromatography and gas chromatography-mass spectrometry (free and silylated). The oils were collected from the interiors and exteriors of high temperature hydrothermal vents and represent hydrothermal pyrolyzates that have migrated to the seafloor by hydrothermal fluid circulation. The downcore sediments are representative of both thermally unaltered and thermally altered sediments. The survey has revealed the presence of oxygenated compounds in samples with a high degree of thermal maturity. Phenols are one class of oxygenated compounds found in these samples. A group of methyl-, dimethyl- and trimethyl-isoprenoidyl phenols (C27-C29) is present in all of the seabed NSO fractions, with the methyl- and dimethyl-isoprenoidyl phenols occurring as major components, and a trimethyl-isoprenoidyl phenol as a minor component. A homologous series of n-alkylphenols (C13-C33) has also been found in the seabed petroleums. These phenols are most likely derived from the hydrothermal alteration of sedimentary organic matter. The n-alkylphenols are probably synthesized under hydrothermal conditions, but the isoprenoidyl phenols are probably hydrothermal alteration products of natural product precursors. The suites of phenols do not appear to be useful tracers of high temperature hydrothermal processes.

Chromatography, Gas↗
PubMed1990

Accumulation of metals and histopathology in Oreochromis niloticus exposed to treated NNPC Kaduna (Nigeria) petroleum refinery effluent.

Accumulation of heavy metals and histopathology were observed in Oreochromis niloticus exposed to treated petroleum refinery effluent from the Nigerian National Petroleum Corporation, Kaduna. Analysis of fish metal burden showed that the fish concentrated trace metals a thousand times above the levels existing in the exposure medium. Some metals were preferentially accumulated more than others and the accumulation was, in decreasing order, Pb, Fe, Zn, Cu, Mn, Cr, Ni, and Cd. Whole fish metal burden was lower in fish from which the gill, liver, and kidney had been removed, suggesting that these organs accumulated the metals more than other tissues. Hemorrhaging of fins was observed in all treatment concentrations except that of the control, and fish exposed to 40 and 50% effluent were most affected. Erosion of the caudal fin was also observed in fish exposed to 40 and 50% effluent. Examination of the organs for histopathology revealed damages to the gills. Gills with edematous fused lamellae congested with blood were observed. No histopathological damage was observed in the liver and kidney. The extent of metal accumulation and histopathological damage were directly related to the effluent concentrations.

Animals↗
PubMed1986

Application of modified Salmonella/microsome prescreen to petroleum-derived complex mixtures and polynuclear aromatic hydrocarbons (PAH)

In some cases, the Salmonella mutagenicity assay may fail to predict the carcinogenic potential of PAH (and of complex mixtures containing PAH) because of nonoptimal in vitro metabolic activation parameters. In this study, 7 petroleum-derived complex mixtures, as well as a number of individual PAH which were representative constituents of such mixtures, were tested in a Salmonella prescreen using quadrant plates with rat or hamster S9 at concentrations approximately 2-8 times those used in the standard assay. Some PAH (perylene, quinoline, benzo[b]chrysene, phenanthrene, anthracene) were optimally activated to mutagens by S9 at 400 microliters/plate. Rat S9 was similar to hamster S9 for most tested PAH, but anthracene and quinoline mutagenicity was enhanced by hamster S9. All 7 complex mixtures were more mutagenic with 200-400 microliters/plate S9; rat was generally slightly more efficient than hamster. Modifying this assay to include a prescreen using a range of S9 concentrations (and perhaps from species other than rat) may improve prediction of the potential carcinogenicity of complex petroleum-derived mixtures.

Animals↗
PubMed1987

Skin tumorigenic potential of crude and refined coal liquids and analogous petroleum products.

The skin tumorigenic potential of seven complex hydrocarbon mixtures was determined: a coal-derived raw blend composed of light and heavy oils, a low- and high-severity hydrotreated product of that blend, and naphthas and fuel oils from the raw blend or from natural petroleum. Male and female C3H/Bdf mice were exposed three times per week to each test mixture by dermal application of 50 microliters of neat, 50, or 25% (w/v) preparations. Room, vehicle, and benzo[alpha]pyrene control groups were run concurrently. The raw blend produced an almost 100% incidence of skin tumors at all three doses while tumorigenicity was considerably decreased by hydrotreating the blend both in terms of incidence and onset. The tumorigenicities of the naphthas and fuel oils derived from the raw blend or from petroleums were low relative to that of the parent mixture. Although tumorigens in the raw blend were much reduced by hydrotreatment, tumorigenicity of the other agents did not parallel the content of polycyclic aromatic hydrocarbons known to be good tumor initiators.

Animals↗
PubMed1980

Acute skin phototoxicity in hairless mice following exposure to crude shale oil or natural petroleum oil.

The acute skin phototoxicity in hairless mice resulting from applications of crude shale oil or natural petroleum oil and exposure to near ultraviolet light has been investigated. In addition, the absorption and excitation-emission spectra of these oils have been described. While the application of crude shale oil alone was shown to elicit acute skin damage, the combination of the crude shale oil and near ultraviolet light induced skin damage much more severe than that produced by either agent alone. In contrast, the application of the natural petroleum oil and near ultraviolet light was less toxic than that of the crude shale oil in the absence of light. These results suggest that a potential health hazard exists from contact with shale oil compounds and exposure to near ultraviolet light from either the sun or artificial sources.

Animals↗
PubMed1988

Dermal carcinogenic activity of petroleum-derived middle distillate fuels.

In general, the carcinogenic potential of petroleum-derived materials is related to the polycyclic aromatic hydrocarbon (PAH) content. Thus it has been assumed that liquids which boil below the PAH distillation range (i.e., below approx. 370 degrees C (700 degrees F) would not be carcinogenic. Several early studies supported this conclusion but were of relatively short duration. Several recent and more rigorous studies have shown that repeated application of certain petroleum-derived materials boiling between approximately 177-370 degrees C (350-700 degrees F) (i.e., middle distillate fuels) can produce tumors in mouse skin. The current studies assessed the tumorigenic potential of a series of middle distillates which varied with respect to boiling range, composition, and source of blending stocks. All of the samples produced evidence of weak tumorigenic activity which was characterized by low tumor yields and long median latencies. However, the majority of the tumor yields were significantly different from the control. There were no apparent differences in response among the samples. Thus the various parameters examined did not substantially influence tumor outcome. In particular, there was no association of tumorigenic activity with aromatic carbon content; this finding, coupled with evidence that PAH levels were low, suggested that the tumorigenic responses were not PAH-dependent. In addition to the tumors, there was evidence of non-neoplastic dermal changes including hyperplasia. These may have contributed to the tumorigenic responses; however, the actual mechanism of tumor induction is unknown.

Administration, Cutaneous↗
PubMed1993

Evaluation of the contribution of chronic skin irritation and selected compositional parameters to the tumorigenicity of petroleum middle distillates in mouse skin.

Two-year skin carcinogenicity studies were conducted in C3H mice to assess the effects of irritation and selected compositional parameters on the carcinogenic potential of four petroleum liquids. Three samples (lightly refined paraffinic oil, LRPO; lightly hydrodesulfurized specialty oil, LHSO; jet fuel, JF) can be generically classified as middle distillates, i.e. distillation occurs between 350 and 700 degrees F (175-370 degrees C). The fourth sample was a Steam Cracked Gas Oil (SCGO) that distilled within the same range. In studies that assess the effects of irritation on tumorigenicity, LRPO was tested undiluted or was diluted to 50% and 25% in either mineral oil (which eliminated irritation of the skin) or toluene (which did not). Undiluted LRPO elicited tumors in 8% of the mice. Both dilution procedures eliminated tumorigenic potential. Thus, it was possible to maintain a visible level of skin irritation equivalent to that elicited by undiluted LRPO without inducing tumors. SCGO elicited a chronic irritant state grossly equivalent to LRPO but was not tumorigenic. Jet Fuel A (JF) was tested undiluted using both a standard skin painting protocol and an intermittent dosing schedule in which treatment was suspended periodically to allow skin irritation to resolve. The standard treatment protocol of JF resulted in both marked skin irritation and tumors in 44% of the mice. However, using the intermittent schedule, the tumor yield was reduced to 2%. Collectively these data demonstrate that tumor formation is not a necessary sequelae to chronic skin irritation. Conversely, prevention of a marked chronic irritant state was accompanied by decreased tumor yield. These data suggest that the chronic irritant state may be a necessary but not sufficient condition for tumor formation. In studies to assess the effects of compositional parameters, a lightly hydrodesulfurized specialty oil (LHSO) similar to LRPO but refined to have negligible levels of sulfur compounds (3 ppm), elicited chronic irritant and tumor responses (10%) similar to LRPO. Thus, the level of sulfur compounds does not appear to affect the tumorigenic activity for products in this boiling range. The SCGO which did not produce tumors contained only aromatic hydrocarbons, a finding consistent with previous reports that aromatics may not be the source of tumorigenic potential in petroleum fractions boiling between 350 and 700 degrees F (175-370 degrees C).

Animals↗
PubMed1982

Influence of ingested petroleum on the reproductive performance and pituitary-gonadal axis of domestic ducks (Anas platyrhynchols).

1. The chronic ingestion of a sublethal dose (5%) of dietary North Sea crude oil delayed the onset of lay in adult Khaki Campbell ducks transferred from a short (8L:16D) to long day (16L:8D) photoperiod and greatly reduced the rate of oviposition and quality (weight and shell thickness) of the eggs subsequently laid. 2. Refeeding the oil-fed birds with the uncontaminated control diet stimulated the rate of egg production and improved egg quality, but in both cases not to the level in the controls. 3. Food intake and the plasma calcium level in the petroleum-fed birds were reduced, but these effects are unlikely to be causally responsible for the adverse effects of petroleum on avian reproduction. 4. Gonadotrophic (luteinizing hormone, LH) hormone secretion in the oil fed birds was not suppressed and the impairment of reproductive performance was not due to low plasma LH levels. 5. The reduced rate of lay in the oil-fed birds was accompanied by low gonadal steroid (progesterone) levels. The detrimental effects of oil and reproduction may be due to direct or indirect effects on the ovary or shell gland.

Animals↗
PubMed1981

Tolerance of adult mallards to subacute ingestion of crude petroleum oil.

Adult male mallards were fed untreated mash or mash containing 1.5% Prudhoe Bay crude oil for 7 days ad lib. During the initial 24 h of exposure to crude petroleum oil, ducks consumed less mash (P less than 0.05) and lost approx. 3.5% of their initial body weight (P less than 0.05), however, neither intake nor body weight differ between groups on days 2-7. Plasma samples collected between 09.00 and 10.00 h on days 0, 1, 3, or 7 indicated that corticosterone, glucose, thyroxine, total protein, and uric acid concentrations, and the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and butyrylcholinesterase (BCHE) were not affected by treatment. These findings suggest that adult mallards may be able to tolerate large quantities of crude petroleum oil mixed in their diet (approx. 25 ml over a 7-day period) without overt or biochemical indications of distress.

Animals↗
PubMed1983

Long term exposure of marine fish to crude petroleum-I. Studies on liver lipids and fatty acids in cod (Gadus morhua) and winter flounder (Pseudopleuronectes americanus).

1. Total lipids, total phospholipids, lipid class and fatty acids have been studied in the livers of cod and winter flounder from the Northwest Atlantic following long-term exposure to crude petroleum. 2. The levels of free fatty acids and total phospholipids were elevated and triglycerides depleted significantly in the males and females of both species in the experimental groups. 3. The essential fatty acids of C20.5, C22.5 and C22.6 series were significantly altered in the oil-exposed animals. 4. These findings indicate that marine fish, following long-term exposure to crude petroleum, tend to (a) use up their stored energy of neutral lipids and (b) develop changes in membrane structure and function.

Animals↗