Aromatic Petroleum Hydrocarbons Research Articles

Embryotoxic effects of benzo[a]pyrene, chrysene, and 7,12-dimethylbenz[a]anthracene in petroleum hydrocarbon mixtures in mallard ducks.

Studies with different avian species have revealed that surface applications of microliter amounts of some crude and fuel oils that coat less than 10% of the egg surface result in considerable reduction in hatching with teratogenicity and stunted growth. Other studies have shown that the embryotoxicity is dependent on the aromatic hydrocarbon content, further suggesting that the toxicity is due to causes other than asphyxia. In the present study the effects of three polycyclic aromatic hydrocarbons identified in petroleum were examined on mallard (Anas platyrhynchos) embryo development. Addition of benzo[a]pyrene (BaP), chrysene, or 7,12-dimethylbenz[a]anthracene (DMBA) to a synthetic petroleum hydrocarbon mixture of known composition and relatively low embryotoxicity resulted in embryotoxicity that was enhanced or equal to that of crude oil when 10 microliter was applied externally to eggs at 72 h of development. The order of ability to enhance embryotoxicity was DMBA greater than BaP greater than chrysene. The temporal pattern of embryonic death was similar to that reported after exposure to crude oil, with additional mortality occurring after outgrowth of the chorioallantois. Retarded growth, as reflected by embryonic body weight, crown-rump length, and bill length, was accompanied by teratogenicity. Abnormal embryos exhibited extreme stunting; eye, brain, and bill defects; and incomplete ossification. Gas chromatographic-mass spectral analysis of externally treated eggs showed the passage of aromatic hydrocarbons including chrysene through the shell and shell membranes to the developing embryos. These findings suggest that the presence of polycyclic aromatic hydrocarbons in petroleum, including BaP, chrysene, and DMBA, significantly enhances the overall embryotoxicity in avian species.

Analysis for petroleum products in marine environments

Petroleum is composed of a complex mixture of hydrocarbons that readily undergo chemical and biological conversions on entering aquatic environments. These conversions lead to the formation of a host of oxygenated products, some of which are potentially toxic to marine life and to the consumer of fishery products. State-of-the-art analytical methods, as employed in our laboratories, utilize glass-capillary gas chromatography in conjunction with mass spectrometry to analyze environmental samples containing trace amounts of aliphatic and aromatic petroleum hydrocarbons. These procedures are applied on a routine basis to the analysis of seawater, sediments and tissues of marine organisms. Despite this analytical proficiency, a need exists for analyzing oxygenated and other polar petroleum products in environmental samples. For example, techniques such as high-performance liquid chromatography (HPLC), in conjunction with on-line fluorometric assay techniques and mass spectrometry, make possible the analysis of polar oxygenated compounds resulting from both chemical and biological conversions. These methodologies are first steps toward the development of routine assay procedures for environmental samples. Current techniques for hydrocarbon analyses and new methods for analyzing polar aromatic compounds are discussed.

Effects of petroleum hydrocarbons on hepatic function in the duck

1. The indocyanine green dye clearance test for hepatic function was determined in mallard ducks before and during the chronic ingestion (7 months) of representative paraffinic or aromatic petroleum hydrocarbons (PH). 2. No mortality or visible symptoms of toxicity occured in any of the tests. Ingestion of 4000 ppm aromatic PH produced significant increases in liver (25%), plasma clearance of indocyanine green (33%) and hepatic blood flow (30%). 3. Although the aromatics elicited a greater hepatic stress response than the paraffins, the ducks tolerated high concentrations of PH for extended periods.

Bioavailability of Crude Oil from Experimentally Oiled Sediments to English Sole (Parophrys vetulus), and Pathological Consequences

English sole (Parophrys vetulus) were exposed to experimentally oiled (Alaskan North Slope crude oil) sediments over a 4-mo period to assess the bioavailability and tissue hydrocarbon distribution kinetics in flatfish. Data were also obtained on hydrocarbon related physiological changes and tissue pathology. Crude oil was mixed with aromatic hydrocarbon-free sediments to a concentration of 700 μg/g dry weight at the beginning of the experiment. During the 1st mo of the experiment this concentration decreased to 400 μg/g dry weight, and remained relatively stable during the remainder of the 4-mo period. Compositional changes were observed in the alkane and aromatic fractions, with a differential decrease in the substituted naphthalenes. Flatfish maintained in such oiled sediments readily took up alkane and aromatic petroleum hydrocarbons from these sediments, and accumulated these in skin, muscle, and liver; 1- and 2-methylnaphthalene and 1,2,3,4-tetramethylbenzene were accumulated to greater extent than other aromatics. Tissue hydrocarbons decreased with time, and after 27-d continuous exposure to oiled sediments only the liver contained detectable levels of hydrocarbons. After 2 mo < 2% of the initial aromatic hydrocarbon load could be detected, and only in the liver in flatfish that were continuously maintained on oiled sediments. Depuration of tissue aromatics differed for various aromatics, 1,2,3,4-tetramethylbenzene and 2-methylnaphthalene being most persistent. Depuration is thought to be due to induction of the aryl hydrocarbon hydroxylase system during initial exposure to oiled sediments. Concomitant with the high tissue hydrocarbon period were found enhanced weight loss and severe hepatocellular lipid vacuolization (HLV). Although the observations, on growth changes and liver pathology are preliminary, the data indicate the need for further detailed study of fish growth abnormalities and pathology in the presence of petroleum hydrocarbons. Key words: flatfish, crude oil, bioavailability, pathology, aromatic hydrocarbons, bottom sediments, depuration

Absence of Aryl Hydrocarbon Hydroxylase (AHH) in Three Marine Bivalves

Bivalves exposed to short-term (4 d) and long-term (6 yr) oil pollution were assayed for aryl hydrocarbon hydroxylase (AHH) and N-demethylase activity. Short-term induction studies were carried out on Mya arenaria, Mytilus edulis, and Ostrea edulis incubated in aqueous extracts of Kuwait crude oil or Bunker C (fuel) oil. For the chronic-induction studies Mya arenaria and Mytilus edulis were collected from oiled clam beds (Arrow Bunker C) in Chedabucto Bay, Nova Scotia. None of the bivalves showed any basal or petroleum-hydrocarbon-induced aryl hydrocarbon hydroxylase or N-demethylase activity, as shown by their inability to metabolize benzopyrene or imipramine. In contrast, oil-free control trout and trout taken from a polluted lake readily metabolized both these compounds. The inability of these bivalves to degrade petroleum aromatic hydrocarbons and the tendency of these compounds to accumulate in their tissues present an opportunity for transfer of unaltered hydrocarbons into the food chain. Key words: aryl hydrocarbon hydroxylase, aromatic hydrocarbon, bivalve, Mya arenaria, Mytilus edulis, Ostrea edulis, petroleum, pollution

Composition and structure of the high-boiling aromatic hydrocarbons in Korobkov and Zhirnov petroleum

1. Aromatic hydrocarbons of the high-boiling fractions from Korobkov and Zhirnov petroleums are mainly mixed compounds which contain about 60% naphthene rings and aliphatic chains, the role of which becomes greater as the boiling temperature of the fraction increases. 2. Benzene, naphthalene, and phenanthrene rings, on the average, make up 58.23 and 12% respectively of the total aromatic rings. In the fractions which boil above 400°C chrysene, and in lesser amounts pyrene, structures appear. The concentration of the anthracene homologs is insignificant. 3. Among the aromatic hydrocarbons (even in the highest boiling fractions), compounds with a single benzene ring, having mainly three and four substituting groups in the 1,2,4 and 1,2,4,5-positions, predominate. The indane ring plays an important part.

Mass spectrometric analysis of aromatic hydrocarbons in petroleum

1. A method has been developed for the analysis of aromatic hydrocarbon types from CnH2n-6 to CnH2n-24 in petroleum fractions boiling in the range 200–450°C. 2. Both molecular and fragment ion peaks can be used in the calculations, and the method permits the determination not only of the group composition, but also the relative amounts of homologs within each group. 3. The use of the molecular ion method is limited to mixtures containing not more than three or four types of compounds.

Analysis of polycyclic aromatic hydrocarbons in petroleum waxes and white mineral oils with appraisal of merits of different methods of analysis

We present a critical discussion, based on our own experimental work, of the merits of two different methods for determining and estimating polycyclic aromatic hydrocarbon (PAH) compounds in refined paraffin waxes and white mineral oils. The Food and Drug Administration (FDA) in the USA has developed a method involving extraction of PAH compounds from wax for quantitative estimation by ultraviolet spectrophotometry of the total PAH content. In W. Germany two methods have been developed: one based on fluorescence of molten wax, the other on paper chromatography applied to a nitromethane extract of PAH compounds. The method employing fluorescence of the molten wax, however, is of little value, because the activating rays, wavelength 254 mμ are absorbed by mono- and bicyclic aromatic components naturally present in the wax. This leads to quenching of the fluorescence, even for waxes passing the requirements of the W. German sulphuric acid test intended to detect fluorescence quenchers. In the other method, the paper-chromatographic behaviour of the PAH extract of the wax is compared with that of three known carcinogenic PAH compounds. We have found that the retention values of these reference carcinogens, added intentionally to the wax extract, are not reproducible and that the fluorescent band is displaced irregularly by other components extracted from the wax, so that a comparison with the reference chromatogram is hardly possible. In addition, quenching takes place, the extent of which is dependent upon the type of PAH and on the type of wax. From our investigations, which cover more PAH compounds than those mentioned explicitly by the W. German law, we conclude that the reliability of both W. German methods is insufficient. We prefer the FDA method, because it is very reproducible and always gives the total PAH content. Moreover, this method has been developed in conjunction with toxicological experiments on animals.

Diagenesis of metabolites and a discussion of the origin of petroleum hydrocarbons

Proteins and carbohydrates are rapidly degraded to compounds of no direct interest in the problem of the origin of petroleum. Lignin, if carried into marine basins in the form of humic substances, is probably the major progenitor of kerogen rather than the precursor of petroleum. Pigments are but minor contributors to petroleum. The fate of fatty acids in a marine environment is not completely understood. Although they may not be directly decarboxylated biochemically, it is shown how they can be converted into oxygenated or dehydrogenated acids more reactive than the parent compounds. Illustrations are also given for Diels-Alder reactions that could account for the formation from these compounds of the alicyclic and aromatic hydrocarbons in petroleum. It is most likely that crude oil is generated in sediments containing concentrations of lipids, the character of which governs the nature of the oil that is formed.