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PubMed1997

Retrospective estimation of exposure to benzene in a leukaemia case-control study of petroleum marketing and distribution workers in the United Kingdom.

OBJECTIVE: To provide quantitative estimates of exposure to benzene for cases and controls in an epidemiology study to investigate the risk of leukaemia in petroleum distribution workers. METHODS: Work histories were obtained for cases and controls together with detailed information on the distribution sites. For each job in the work history, an estimate of exposure (parts per million (ppm)) was obtained by multiplying a measure derived from exposure data by modifying factors to reflect the differences between the conditions that existed at the time of measurement and those at the time of interest. The modifying factors used related to job activity, the number of road tankers loaded, the benzene content of the gasoline, the mixture of products handled, temperature, and loading technology. Cumulative exposures for each case and control were obtained by multiplying the exposure estimates for each job by the duration of time in the respective jobs, and summing these over all jobs in the work history. Peak exposure and exposure through dermal contact were quantitatively classified for each job. RESULTS: Measured exposures were obtained for 30 job categories, and ranged from 0.003 to 8.20 ppm. 40% of work histories were assigned background exposures, with a further 34% assigned the exposure estimate for a driver carrying out top submerged loading of motor fuel into road tankers. Cumulative exposures ranged from < 1 to > 200 ppm-years, although 81% were < 5 ppm-years. Comparison of the exposure estimates for selected jobs with data from sources not used in the study showed similar results. CONCLUSION: The estimates of exposure to benzene in this study provide a sound basis for the epidemiological analyses.

Benzene↗
PubMed2002

Updated epidemiological study of workers at two California petroleum refineries, 1950-95.

OBJECTIVES: To further assess the potential role of occupational exposures on mortality, a second update of a cohort study of workers at two petroleum refineries in California was undertaken. METHODS: Mortality analyses were based on standardised mortality ratios (SMRs) and 95% confidence intervals (95% CIs) using the general population of California as a reference. Additional analyses of lymphatic and haematopoietic cancer deaths and diseases related to asbestos were undertaken. RESULTS: The update consisted of 18,512 employees, who contributed 456,425 person-years of observation between 1950 and 1995. Both overall mortality and total cancer mortality were significantly lower than expected, as were several site specific cancers and non-malignant diseases. In particular, no significant increases were reported for leukaemia cell types or non-Hodgkin's lymphoma. Mortality excess from multiple myeloma was marginally significant. The excess was confined to employees enrolled before 1949. Furthermore, there was no significant upward trend based on duration of employment, which argues against a causal interpretation relative to employment or exposures at the refineries. No increase was found for diseases related to asbestos: pulmonary fibrosis; lung cancer; or malignant mesothelioma. There was no significant increase in mortality from any other cancers or non-malignant diseases. CONCLUSION: This second update provides additional reassurance that employment at these two refineries is not associated with increased risk of mortality.

Asbestos↗
PubMed1975

Some effects of petroleum on estuarine and marine microorganisms.

Degradation of mixed hydrocarbon substrate in a system comprising water from an environment relatively free of oil and a sediment inoculum from an oil-contaminated site was significantly greater than when sediment from the non-oil-contaminated environment served as inoculum. Mixed hydrocarbon substrate, however, was observed to have a limiting effect on the growth of autochthonous bacteria from the non-oil-contaminated estuarine source. Growth and cell yield were similarly reduced when marine sediment bacteria were cultured in seawater supplemented with mixed hydrocarbon substrate. The addition of a South Louisiana crude oil or a No. 2 fuel oil to water and sediment collected from a marsh area of Chesapeake Bay showed no limiting effects on growth of the total heterotrophic microbial flora when examined over a 28-day period. However, results of these studies indicate that the effects of petroleum on microoganisms should be examined carefully under conditions closely approximating those in situ.

Aerobiosis↗
PubMed2000

Effects of Pinus sylvestris root growth and mycorrhizosphere development on bacterial carbon source utilization and hydrocarbon oxidation in forest and petroleum-contaminated soils.

The hypothesis that Pinus sylvestris L. root and mycorrhizosphere development positively influences bacterial community-linked carbon source utilization, and drives a concomitant reduction in mineral oil levels in a petroleum hydrocarbon- (PHC-) contaminated soil was confirmed in a forest ecosystem-based phytoremediation simulation. Seedlings were grown for 9 months in large petri dish microcosms containing either forest humus or humus amended with cores of PHC-contaminated soil. Except for increased root biomass in the humus/PHC treatment, there were no other significant treatment-related differences in plant growth and needle C and N status. Total cell and culturable bacterial (CFU) densities significantly increased in both rhizospheres and mycorrhizospheres that actively developed in the humus and PHC-contaminated soil. Mycorrhizospheres (mycorrhizas and extramatrical mycelium) supported the highest numbers of bacteria. Multivariate analyses of bacterial community carbon source utilization profiles (Biolog GN microplate) from different rhizosphere, mycorrhizosphere, and bulk soil compartments, involving principal component and correspondence analysis, highlighted three main niche-related groupings. The respective clusters identified contained bacterial communities from (i) unplanted bulk soils, (ii) planted bulk PHC and rhizospheres in PHC-contaminated soils, and (iii) planted bulk humus and rhizosphere/mycorrhizosphere-influenced humus, and mycorrhizosphere-influenced PHC contaminated soil. Correspondence analysis allowed further identification of amino acid preferences and increased carboxylic/organic acid preferences in rhizosphere and mycorrhizosphere compartments. Decreased levels of mineral oil (non-polar hydrocarbons) were detected in the PHC-contaminated soil colonized by pine roots and mycorrhizal fungi. These data further support our view that mycorrhizosphere development and function plays a central role in controlling associated bacterial communities and their degradative activities in lignin-rich forest humus and PHC-contaminated soils.

Bacteria↗
PubMed1993

Kidney cancer and hydrocarbon exposures among petroleum refinery workers.

To evaluate the hypothesis of increased kidney cancer risk after exposure to hydrocarbons, especially those present in gasoline, we conducted a case-control study in a cohort of approximately 100,000 male refinery workers from five petroleum companies. A review of 18,323 death certificates identified 102 kidney cancer cases, to each of whom four controls were matched by refinery location and decade of birth. Work histories, containing an average of 15.7 job assignments per subject, were found for 98% of the cases and 94% of the controls. To each job, industrial hygienists assigned semiquantitative ratings for the intensity and frequency of exposures to three hydrocarbon categories: nonaromatic liquid gasoline distillates, aromatic hydrocarbons, and the more volatile hydrocarbons. Ratings of "present" or "absent" were assigned for seven additional exposures: higher boiling hydrocarbons, polynuclear aromatic hydrocarbons, asbestos, chlorinated solvents, ionizing radiation, and lead. Each exposure had either no association or a weak association with kidney cancer. For the hydrocarbon category of principal a priori interest, the nonaromatic liquid gasoline distillates, the estimated relative risk (RR) for any exposure above refinery background was 1.0 (95% confidence interval [CI] 0.5-1.9). Analyses of cumulative exposures and of exposures in varying time periods before kidney cancer occurrence also produced null or near-null results. In an analysis of the longest job held by each subject (average duration 9.2 years or 40% of the refinery work history), three groups appeared to be at increased risk: laborers (RR = 1.9, 95% CI 1.0-3.9); workers in receipt, storage, and movements (RR = 2.5, 95% CI 0.9-6.6); and unit cleaners (RR = 2.3, 95% CI 0.5-9.9).

Carcinoma, Renal Cell↗
PubMed1993

A retrospective mortality study among Canadian petroleum marketing and distribution workers.

We conducted a retrospective mortality study among 6672 petroleum marketing and distribution workers from 226 locations throughout Canada. These employees worked for at least 1 year in the marketing distribution segment from 1964 through 1983 or were annuitants as of 1964. Industrial hygienists assigned hydrocarbon (HC) exposure frequency scores for several jobs, departments, and job functions. We computed standardized mortality ratios for the total cohort, HC exposure frequency groups, and tank truck drivers, and we also used Poisson regression techniques to model mortality for selected causes of death according to HC exposure frequency. Results indicate overall mortality below that of the general Canadian population for all marketing distribution workers [Standardized mortality ratio (SMR) = 0.88]. Mortality from aortic aneurysms was significantly elevated in all marketing/distribution workers (SMR = 1.79) but was due to raised mortality in nonexposed workers (SMR = 2.80). Tank truck drivers showed significantly elevated mortality due to leukemia (SMR = 3.35) based on five deaths. The leukemia findings were not evident in the larger group of marketing distribution workers classified as exposed to hydrocarbons (SMR = 1.01). No other cause of death was elevated in truck drivers. The leukemia findings are suggestive of a possible influence due to exposure to HCs in tank truck drivers, although other explanations cannot be ruled out. Other findings of elevated mortality in the marketing distribution group are generally not statistically significant. These included moderately increased mortality due to multiple myeloma, malignant melanoma, and kidney cancer. Small numbers of observed and expected deaths limit concise interpretations for these diseases.

Canada↗
PubMed1994

Chronic and initiation/promotion skin bioassays of petroleum refinery streams.

Nine refinery streams were tested in both chronic and initiation/promotion (I/P) skin bioassays. In the chronic bioassay, groups of 50 C3H/HeJ mice received twice weekly applications of 50 microl of test article for at least 2 years. In the initiation phase of the I/P bioassay, groups of CD-1 mice received an initiating dose of 50 microl of test article for 5 consecutive days, followed by promotion with 50 microl of phorbol-12-myristate-13-acetate (0.01% w/v in acetone) for 25 weeks. In the promotion phase of the I/P bioassay, CD-1 mice were initiated with 50 microl of 7,12-dimethylbenzanthracene (0.1% w/v in acetone) or acetone, followed by promotion with 50 microl of test article twice weekly for 25 weeks. The most volatile of the streams, sweetened naphtha, and the least volatile, vacuum residuum, were noncarcinogenic in both assays. Middle distillates, with a boiling range of 150 degrees-370 degrees C, demonstrated carcinogenic activity in the chronic bioassay and acted as promoters but not initiators in the I/P bioassay. Untreated mineral oil streams displayed initiating activity and were carcinogenic in the chronic bioassay, presumably due to the presence of polycyclic aromatic hydrocarbons of requisite size and structure. A highly solvent-refined mineral oil stream lacked initiating activity. These results indicate that the I/P bioassay, which takes 6 months to complete, may be a good qualitative predictor of the results of a chronic bioassay, at least for petroleum streams. Furthermore, the I/P bioassay can provide insight into possible mechanisms of tumor development.

Alkanes↗
PubMed1996

Benzene exposure in the petroleum distribution industry associated with leukemia in the United Kingdom: overview of the methodology of a case-control study.

This paper describes basic principles underlying the methodology for obtaining quantitative estimates of benzene exposure in the petroleum marketing and distribution industry. Work histories for 91 cases of leukemia and 364 matched controls (4 per case) identified for a cohort of oil distribution workers up to the end of 1992 were obtained, primarily from personnel records. Information on the distribution sites, more than 90% of which were closed at the time of data collection, was obtained from site visits and archive material. Industrial hygiene measurements measured under known conditions were assembled for different tasks. These were adjusted for conditions where measured data were not available using variables known to influence exposure, such as temperature, technology, percentage of benzene in fuel handled, products handled, number of loads, and job activity. A quantitative estimate of dermal contact and peak exposure was also made.

Benzene↗
PubMed1996

The relationship between low-level benzene exposure and leukemia in Canadian petroleum distribution workers.

This study was conducted to evaluate the relationship between leukemia occurrence and long-term, low-level benzene exposures in petroleum distribution workers. Fourteen cases were identified among a previously studied cohort [Schnatter et al., Environ Health Perspect 101 (Suppl 6):85-89 (1993)]. Four controls per case were selected from the same cohort, controlling for birth year and time at risk. Industrial hygienists estimated workplace exposures for benzene, without knowledge of case-control status. Average benzene concentrations ranged from 0.01 to 6.2 ppm. Company medical records were used to abstract information on other potential confounders such as cigarette smoking. Odds ratios were calculated for several exposure metrics. Conditional logistic regression modeling was used to control for potential confounders. The risk of leukemia was not associated with increasing cumulative exposure to benzene for these exposure levels. Duration of benzene exposure was more closely associated with leukemia risk than other exposure metrics, although results were not statistically significant. A family history of cancer and cigarette smoking were the two strongest risk factors for leukemia, with cumulative benzene exposure showing no additional risk when considered in the same models. This study is consistent with other data in that it was unable to demonstrate a relationship between leukemia and long-term, low-level benzene exposures. The power of the study was limited. Thus, further study on benzene exposures in this concentration range are warranted.

Adult↗
PubMed2004

Utilizing three-dimensional fluorescence's red-shift cascade effect to monitor mycobacterium PRY-1 degradation of aged petroleum.

Samples of Mycobacterium PRY-1 inoculated motor oil are subjected to three-dimensional fluorescence spectroscopy to document the shifting of excitation/emission maxima as the solutions undergo serial dilutions. Effects such as self-quenching of individual polycyclic aromatic hydrocarbons (PAHs) and energy transfer between PAHs combine to produce large red-shifts in the resulting fluorescence emission spectra. This process is repeated over a series of weeks and is compared to preceding spectra to gauge the microbial degradation of the petroleum. Results show a two-fold, or 75%, PAH contaminant degradation by Mycobacterium PRY-1 over a 140-day growth period.

Biodegradation, Environmental↗
PubMed2003

Electron microscopic findings in BAL of a fire-eater after petroleum aspiration.

Hydrocarbon pneumonitis, known also as fire-eater pneumonia, always develops after aspiration of low-viscosity, volatile hydrocarbides. Despite the presence of clear-cut indicators for an infection, it is considered to be an acute pseudoinfectious lung disease. In this article, we report on a relatively rare clinical picture of a 30-year-old man after accidental petroleum aspiration. In addition to the usual clinical and instrumental examinations, we also performed, for the first time, electron microscopic investigations of the BAL specimen. A striking finding was the occurrence of macrophages (40%) with numerous lipoid inclusions that exhibited all morphologic signs of an activation as well as neutrophil granulocytes (33%), lymphocytes (21%), and eosinophils (6%). Despite a large and necrotizing infiltration of the right lower lobe, the clinical course was uneventful with complete recovery.

Adult↗
PubMed2005

Detection of NAD+-dependent alcohol dehydrogenase activities in YR-1 strain of Mucor circinelloides, a potential bioremediator of petroleum contaminated soils.

Different soluble NAD+-dependent alcohol dehydrogenase (ADH) isozymes were detected in cell-free homogenates from aerobically grown mycelia of YR-1 strain of Mucor circinelloides isolated from petroleum- contaminated soil samples. Depending on the carbon source present in the growth media, multiple NAD+-dependent ADHs were detected when hexadecane or decane was used as the sole carbon source in the culture media. ADH activities from aerobically or anaerobically grown mycelium or yeast cells, respectively, were detected when growth medium with glucose added was the sole carbon source; the enzyme activity exhibited optimum pH for the oxidation of different alcohols (methanol, ethanol, and hexadecanol) similar to that of the corresponding aldehyde (approximately 7.0). Zymogram analysis conducted with partially purified fractions of extracts from aerobic mycelium or anaerobic yeast cells of the YR-1 strain grown in glucose as the sole carbon source indicated the presence of a single NAD+-dependent ADH enzyme in each case, and the activity level was higher in the yeast cells. ADH enzyme from mycelium grown in different carbon sources showed high activity using ethanol as substrate, although higher activity was displayed when the cells were grown in hexadecane as the sole carbon source. Zymogram analysis with these extracts showed that this particular strain of M. circinelloides has four different isozymes with ADH activity and, interestingly, one of them, ADH4, was identified also as phenanthrene-diol- dehydrogenase, an enzyme that possibly participates in the aromatic hydrocarbon biodegradation pathway.

Alcohol Dehydrogenase↗
PubMed2002

Presence and physiologic regulation of alcohol oxidase activity in an indigenous fungus isolated from petroleum-contaminated soils.

A soluble alcohol oxidase (AO) activity was detected in the mycelium of a filamentous fungus strain named YR-1, isolated from petroleum-contaminated soils. AO activity from aerobically grown mycelium was detected in growth media containing the hydrocarbons decane or hexadecane; the enzyme activity exhibited optimum pH for the oxidation of different alcohols (methanol, ethanol, and hexadecanol) similar to that of the corresponding aldehyde. Zymogram analysis conducted with purified fractions from aerobic mycelium of YR-1 strain extracts indicated the existence of two AO enzymes (AO-1 and AO-2). Purified samples of both enzymes analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis indicated the presence of three protein bands with molecular sizes 20,38, and 46 kDa that could be part of the native enzyme. In samples of both enzymes, the 46-kDa protein gave a positive reaction in immunodetection experiments with antibodies directed against AO from Hansenula polymorpha. The purified AO-2 enzyme oxidized different alcohols, although higher activity was displayed with hexadecanol. Km values obtained for methanol and hexa-decanol indicated a higher affinity for the latter. Analysis of the aminoter-minal sequence of the 46-kDa protein of AO-2 enzyme indicated significant similarity to enzymes involved in the metabolism of biphenyl polychloride compounds.

Alcohol Oxidoreductases↗
PubMed1978

The effects of ingested petroleum on oviposition and some aspects of reproduction in experimental colonies of mallard ducks (Anas platyrhynchos).

Compared to unmated mallard ducks fed an uncontaminated diet, unmated birds given food contaminated with 3 ml South Louisiana crude oil per 100 g dry weight showed an 84% decline in the daily rate of oviposition, a 33% decrease in egg-shell thickness and at autopsy more than 82% of the ovarian mass consisted of atretic follicles. Similar studies on groups of mated females showed that although the addition of 1 ml South Louisiana crude oil/100 g dry food had no effect on the daily rate of oviposition, none of the eggs had been fertilized while a concentration of 3 ml South Louisiana crude oil/100 g dry food suppressed the daily rate of oviposition significantly. Less than 25% of these eggs had been fertilized and only 40% of the fertilized eggs yielded viable ducklings. In both of these groups of mated birds, normal patterns of oviposition, fertilization and hatchability were restored after removal of petroleum from the diet. The addition of 1 ml Kuwait crude oil/100 g dry food had no effect on the rate of oviposition, the incidence of fertility or the hatchability of the fertilized eggs. The addition of 3 ml oil/100 g dry food completely abolished oviposition, but a normal rate of oviposition was restored when the concentration of the crude oil was reduced from 3 to 1 ml/100 g dry food. However, the incidence of fertilization remained low and none of the fertilized eggs gave rise to viable ducklings. Kuwait crude oil had no effect on shell thickness.

Animals↗
PubMed2004

Multiple mechanisms contribute to the biodegradation of benzo[a]pyrene by petroleum-derived multicomponent nonaqueous-phase liquids.

The presence of multicomponent nonaqueous-phase liquids (NAPLs) on contaminated sites critically alters the biodegradation susceptibility of many target pollutants, including polycyclic aromatic hydrocarbons. This study investigated the effects of petroleum-derived multicomponent NAPLs on biodegradation of benzo[a]pyrene by a bacterial consortium in liquid culture. When high-boiling point diesel fuel distillate (HBD)-NAPL was added to liquid culture, the consortium initiated benzo[a]pyrene mineralization after a lag period of several days. This lag period was not observed in the mineralization of phenanthrene, anthracene, and chrysene by the same consortium with HBD. Nonaqueous-phase liquids added to cultures pregrown before experimentation largely affected the extent of benzo[a]pyrene mineralization and the duration of lag period in subsequent experiments, suggesting that NAPL presence was important for maintaining the efficiency of the mineralizing consortium. Experiments using further fractionated oil components suggested that stimulation of benzo[a]pyrene mineralization by NAPLs was fraction dependent; an alkylated aromatic fraction was more effective than aromatic and aliphatic fractions. The effect of NAPL on benzo[a]pyrene biodegradation was determined to be multimechanistic; that is, NAPL acted as a cosolvent for polycyclic aromatic hydrocarbon dissolution, as a substrate to induce cometabolic degradative pathways, and as an agent to formulate the effective microbial consortium. Data suggest that the third mechanism was of particular importance for rapid benzo[a]pyrene mineralization.

Benzo(a)pyrene↗
PubMed2004

Methods to assess the amenability of petroleum hydrocarbons to bioremediation.

Bioremediation has achieved acceptance as a cost-effective technique for the remediation of soils and groundwater contaminated with petroleum hydrocarbons (PHC). A range of laboratory techniques to assess the biodegradability and bioavailability of PHCs are presented. Biodegradability and bioavailability are important determinants of the bioremediation performance of PHCs. Novel methods for the assessment of the bioavailability of PHC components are described. The techniques are demonstrated for a hydraulic fluid and a spindle oil from a contaminated site. Biodegradation is measured by oxygen consumption and carbon dioxide production. Bioavailability of the PHCs is estimated based on the PHC-water partitioning of tracer compounds and a novel analysis of gas chromatograms based on Raoult's law. The PHCs tested were only partially biodegradable (< 25% in 78 d) due to the low solubility and likely recalcitrance of some of their components. The combination of techniques outlined is expected to be of use in assessing the likely bioremediation performance of PHCs for which published data are scarce or inadequate.

Biodegradation, Environmental↗
PubMed2004

Degradation of petroleum hydrocarbons in two sub-antarctic soils: influence of an oleophilic fertilizer.

In order to determine the long-term effects of fertilizer on the degradation rate and the toxicity of hydrocarbons in sub-Antarctic soils contaminated by petroleum hydrocarbons, a field study was initiated in December 2000 on two different soils of the Kerguelen Islands (69 degrees 42'E, 49 degrees 19'S). The number of hydrocarbon-degrading bacteria (HDB) increased greatly after crude-oil and diesel-fuel contamination, and the fertilizer addition had a favorable effect on HDB growth and activity. Hydrocarbon-degrading bacteria counts remained high until the end of the experiment although the total hydrocarbon content in all contaminated soils was reduced to 80 to 90% of their initial value after 330 d. Degradation of n-alkanes was enhanced significantly in the presence of the fertilizer, while the degradation of polycyclic aromatic hydrocarbons (PAHs) was only barely enhanced. Toxicity results showed a noticeable reduction with time, although toxicity remained present and important in both soils at the end of the experiment. In addition, fertilized plots showed a toxic signal greater than unfertilized ones. Overall results clearly show that fertilizer addition improves the rate of degradation of both oil contaminants. However, remaining toxic residues may constitute a drawback of the fertilizer-assisted biodegradation process at low temperatures.

Antarctic Regions↗
PubMed2006

Risk assessment of the National Institute of Standards and Technology petroleum crude oil standard water accommodated fraction: further application of a copepod-based, full life-cycle bioassay.

The U.S. National Institute of Standards and Technology (NIST) petroleum crude oil was used to generate NIST water-accommodated hydrocarbon fractions (WAFs) for standardized assessment of crude oil effects on the copepod Amphiascus tenuiremis. Effects were assessed using a 96-well microplate, full life-cycle test. Briefly, nauplii (age, 24 h) were reared individually to adults (n > or =120 nauplii/treatment) in microplate wells containing 200 microl of treatment solution (seawater control [0%] or 10, 30, 50, or 100% NIST-WAF). Nauplii were monitored through development to adulthood, and mature virgin male:female pairs mated in wells containing original treatments (<30 d). A second bioassay using 0, 10, 30, and 50% WAFs (n > or =60 nauplii/treatment) was conducted to assess the effects of ultraviolet (UV) light on naupliar endpoints (<16 d). In the first experiment, nauplius-to-copepodite survival in exposures to 100% WAF was 27% +/- 6% lower than in controls (92% +/- 1%), but copepodite-to-adult survival was greater than 90% across all treatments. Analysis of development curves showed that nauplii in the 10% WAF developed into copepodites 25% faster, whereas nauplii in the 50 and 100% WAFs developed 17% slower, than controls. Copepodite development into male and female copepods was significantly delayed (2 and 4 d, respectively) in the 100% WAF compared to controls. Although none of the WAF exposures had significant effects on fertilization success or total viable production (p > 0.05), embryo hatching in the 100% WAF was significantly less (70.0% +/- 21.2%) than that in controls (87.0% +/- 19.4%). Results from the UV bioassay showed that relatively short exposures (<14 d) to 30 and 50% WAFs in the presence of UV light caused negative effects on copepod survival and development. Naupliar-stage survival and developmental endpoints were the most sensitive indicators of exposure to the NIST crude oil WAF

Animals↗