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PubMed2002

Burial, exportation and degradation of acyclic petroleum hydrocarbons following a simulated oil spill in bioturbated Mediterranean coastal sediments.

A field study was conducted in a French Mediterranean littoral (Gulf of Fos) in order to determine the role of bioturbation processes during the bioremediation of oil-contaminated sediments. Inert particulate tracers (luminophores) and Arabian light crude oil were deposited at the surface of sediment cores incubated in situ for 2, 6 and 12 months. After incubation, luminophores and hydrocarbons presented roughly similar depth distributions in the sediment, showing a continuous burial of material until 55 mm depth. Short-chain (< or = n-C25) n-alkanes were totally removed from the sedimentary column after 6 months, whereas approximately 20% of heavier n-alkanes (e.g. n-C30) and of isoprenoid hydrocarbons (pristane (Pr) and phytane (Ph)) remained at the end of the experiment. The determination of the degradation constant and the turn-over rate of individual hydrocarbon indicated that C17-25 n-alkanes were degraded two to three times faster than longer homologues and than pristane and phytane. Using the 17alpha,21beta-C30-hopane as an internal inert reference, we could demonstrate that, after 12 months of in situ incubation, 55% of the losses of the n-alkanes < or = C25 and 35% of the losses of the heavier n-alkanes and of Pr and Ph were due to biodegradation processes. These results demonstrate that the activity of benthic organisms can have a significant influence on the qualitative and quantitative fate of acyclic hydrocarbons following a petroleum contamination in marine coastal sediments.

Animals↗
PubMed2003

Effects of temperature on mineralisation of petroleum in contaminated Antarctic terrestrial sediments.

Although petroleum contamination has been identified at many Antarctic research stations, and is recognized as posing a significant threat to the Antarctic environment, full-scale in situ remediation has not yet been used in Antarctica. This is partly because it has been assumed that temperatures are too low for effective biodegradation. To test this, the effects of temperature on the hydrocarbon mineralisation rate in Antarctic terrestrial sediments were quantified. 14C-labelled octadecane was added to nutrient amended microcosms that were incubated over a range of temperatures between -2 and 42 degrees C. We found a positive correlation between temperature and mineralisation rate, with the fastest rates occurring in samples incubated at the highest temperatures. At temperatures below or near the freezing point of water there was a virtual absence of mineralisation. High temperatures (37 and 42 degrees C) and the temperatures just above the freezing point of water (4 degrees C) showed an initial mineralisation lag period, then a sharp increase in the mineralisation rate before a protracted plateau phase. Mineralisation at temperatures between 10 and 28 degrees C had no initial lag phase. The high rate of mineralisation at 37 and 42 degrees C was surprising, as most continental Antarctic microorganisms described thus far have an optimal temperature for growth of between 20 and 30 degrees C and a maximal growth temperature <37 degrees C. The main implications for bioremediation in Antarctica from this study are that a high-temperature treatment would yield the most rapid biodegradation of the contaminant. However, in situ biodegradation using nutrients and other amendments is still possible at soil temperatures that occur naturally in summer at the Antarctic site we studies (Casey Station 66 degrees 17(') S, 110 degrees 32(') E), although treatment times could be excessively long.

Alkanes↗
PubMed2001

Ability of fractionated petroleum refinery effluent to elicit cyto- and photocytotoxic responses and to induce 7-ethoxyresorufin-O-deethylase activity in fish cell lines.

The ability of fractionated petroleum refinery effluent to cause cellular responses in fish cell lines was evaluated. The cellular responses, which included direct and indirect cytotoxicity, photocytotoxicity and induction of 7-ethoxyresorufin-O-deethylase (EROD) activity, may potentially be linked to sublethal effects observed in effluent-exposed fish and fish larvae. In order to be able to quantify cellular responses rapidly, microtitre plates were used along with fluorescent probes. For the quantification of cyto- and photocytotoxicity, the fluorescent probes were alamar Blue and carboxyfluorescein diacetate acetoxymethyl ester (CFDA-AM), which monitor metabolic activity and cell membrane integrity, respectively. EROD activity was measured as the rate of conversion by EROD of the substrate 7-ethoxyresorufin to its fluorescent product, resorufin. Effluent from an Ontario refinery was fractionated into aqueous and particulate phase. As well, a solid phase extract (SPE) was used to prepare concentrated effluent for testing in the cell lines. The effluent was able to elicit all of the responses of interest although significant cyto- and photocytotoxicity required effluent equivalent concentrations above 100% effluent and could only be revealed upon exposure of cells to the SPE concentrated effluent. Based on their retention on C18, the cytotoxicants are likely to be non-polar to moderately polar chemicals. The presence of polar compounds affecting cellular metabolism was indicated by the responses of exposed cells to a 90% aqueous phase effluent. In contrast to cyto- and photocytotoxicity, EROD induction occurred at effluent equivalent concentrations well below 100% effluent and was elicited by the SPE and the particulate fraction thereby suggesting that most EROD-inducers were particle-bound. Among other applications, the described techniques could help to determine the source of causative agents of sublethal effects in the refining process.

Animals↗
PubMed1999

Levels and trends of PCBs, chlorinated pesticides and petroleum hydrocarbons in mussels from the NW Mediterranean coast: comparison of concentrations in 1973/1974 and 1988/1989.

A mussel watch survey was conducted in 1988-1989 along the Mediterranean coast of France and Italy, between Sete and Genoa, in order to assess contamination by organochlorine pesticides, PCBs and petroleum hydrocarbons. Results show concentrations of DDTs (average 130 ng g-1 dry wt.) and PCBs (average 527 ng g-1 dry wt.) higher in coastal areas receiving river discharges and close to large cities. Concentrations of total aliphatics (average 470 micrograms g-1 dry wt.) and PAHs (average 233 micrograms g-1 dry wt.) were generally higher also near large harbours, namely Marseille, Toulon and Genoa. PAHs in mussel samples from Genoa and Monaco were mostly of pyrolytic sources, likely forest fires and exhaust gases from cars, whereas PAHs in other stations were mainly of petrogenic sources. Comparison of chlorinated hydrocarbon concentrations measured in 1988-1989 with those measured in a similar survey carried out at the same sites in 1973-1974, shows that DDTs and PCBs decreased by a factor of approximately 5 in 15 years. This decrease is in agreement with the ban on DDT implemented in 1975 in western Europe and gradual cessation of PCBs production in the 1970s and 1980s. Nevertheless, the residues of these compounds measured in mussels confirm the well-known long persistence of DDTs and PCBs, which are still present in relatively high concentrations in a few areas.

Animals↗
PubMedDate not supplied

High molecular weight polycyclic aromatic hydrocarbons in hydrothermal petroleums from the Gulf of California and Northeast Pacific Ocean.

Hydrothermal petroleums and heavy tars have been analyzed for polycyclic aromatic hydrocarbons (PAH) with molecular weights greater than that of coronene (300 da). Samples from the hydrothermal systems in the Guaymas Basin (Gulf of California) and in the Escanaba Trough and Middle Valley (Northeastern Pacific) were analyzed by gas chromatography-mass spectrometry and high pressure liquid chromatography with diode-array absorbance detection. Mass spectra and fluorescence spectra were used to characterize the compounds. Several large PAHs with six and more rings were identified among the heavy PAH. Production routes via one-ring build-up and Scholl-condensation are proposed to explain the observed structures. The variations in PAH concentrations and distributions between samples from different locales are a consequence of the hydrothermal conditions of generation, migration, and post-depositional alteration.

Gas Chromatography-Mass Spectrometry↗
PubMedDate not supplied

Carbon isotope systematics of individual hydrocarbons in hydrothermal petroleum from Escanaba Trough, northeastern Pacific Ocean.

We submitted individual aliphatic and polycyclic aromatic hydrocarbons in samples of hydrothermal petroleum from Escanaba Trough to compound specific isotope analysis to trace their origins. The carbon isotope compositions of the alkanes and polycyclic aromatic hydrocarbons (means -27.5 and -24.7%, respectively) reflect a primarily terrestrial organic matter source.

Alkanes↗
PubMed2003

Distribution of petroleum hydrocarbon in sediment from coastal area receiving industrial effluents in Kuwait.

Sediment samples from the coastal area facing Shuaiba industrial area (15 x 1.5 km(2)) were examined for contamination with petroleum hydrocarbons. Aliphatic hydrocarbons in sediment extracts were characterized largely by unresolved complex mixture from nC(22)-nC(33). The sediment samples from the upstream area facing Mina Al-Ahmadi refinery to Shuaiba Harbor were heavily polluted with polycyclic aromatic hydrocarbons (PAHs) possibly due to the higher depth in the area created for a navigational channel to the harbor. PAHs at these locations exceeded the probable effect levels with reference to sediment quality guidelines.

Environmental Monitoring↗
PubMed2004

Assessment of contamination by heavy metals and petroleum hydrocarbons in sediments of Montevideo Harbour (Uruguay).

As part of the first environmental assessment within Montevideo Harbour, in summer and winter of 1998, sediments samples were collected at eight locations to determine the spatial distribution of anthropogenic pollutants. Muddy sediments with high organic matter content dominate the study area. Heavy metal levels indicated that sediments were highly polluted with Zn (overall mean: 312+/-102 microg g(-1) dry sediment), Pb (85+/-31), Cu (89+/-25), Cr (162+/-62), and Hg (0.63+/-0.3) and moderately with Ni (30+/-2) and Ag (1.2+/-0.4). Depending on location and season, aliphatic hydrocarbons reached from 21 to 120 microg g(-1), while the unresolved complex mixture represented up to 76% of the total aliphatic fraction. Total PAH concentrations ranged from 1.56 to 90.44 microg g(-1); except at one location, petroleum derivatives were identified as main local source. The results pointed out that almost all the harbour area presented some substances that can cause adverse biological effects, especially in the inner region where all metals are above PEL levels. Principal components analysis confirmed that the inner harbour region is most severely affected by the pollutants and it was possible to differentiate three regions according to their environmental quality.

Environmental Monitoring↗
PubMed2001

Influence of dispersants on the bioavailability and trophic transfer of petroleum hydrocarbons to larval topsmelt (Atherinops affinis).

Use of chemical dispersants as oil spill clean-up agents may alter the normal behavior of petroleum hydrocarbons (PH) by increasing their functional water solubility, resulting in increased bioavailability and altered interactions between dispersant, oil, and biological membranes. The objective of this research was to determine the impact of dispersing agents on PH bioavailability and trophic transfer to larval fish from primary levels of a marine food chain. Uptake, bioaccumulation, depuration, and metabolic transformation of a model PH, [14C]naphthalene, were measured and compared for Prudhoe Bay crude oil (PBCO) dispersed with Corexit 9527(R) (DO) and undispersed preparations of the water-accommodated fraction (WAF) of PBCO. The model food chain consisted of a primary producer, Isochrysis galbana; and a primary consumer, the rotifer, Brachionus plicatilis; and larval topsmelt, Atherinops affinis. Direct aqueous (AQ) exposure was compared with combined aqueous and dietary (AQ&D) exposure. Dispersants altered the uptake and depuration processes of naphthalene, independent of aqueous concentrations, in primary trophic species of a marine food chain. The amount of naphthalene taken up by topsmelt was initially significantly (P < or = 0.05) enhanced in the presence of dispersant, reaching a maximum more quickly than undispersed samples. Dispersion treatment significantly increased naphthalene dispension in topsmelt (P < or = 0.05) from both AQ and AQ&D exposures. No significant change in naphthalene uptake by fish was observed with the addition of contaminated food for either WAF or DO medium; however, both uptake and depuration rate constants varied significantly with route of exposure consistent with greater naphthalene turnover. The majority (> or = 72%) of naphthalene-derived radioactivity from fish tissue following all exposures was in the parent form, with smaller quantities of alpha- and beta-naphthols, alpha- and beta-naphthyl sulfates, and an unidentified derivative.

Animals↗
PubMed2001

An assessment of natural biotransformation of petroleum hydrocarbons and chlorinated solvents at an aquifer plume transect.

Field biogeochemical characterization and laboratory microcosm studies were performed to assess the potential for future biotransformation of trichloroethylene (TCE) and toluene in a plume containing petroleum hydrocarbons and chlorinated solvents at the former Wurtsmith Air Force Base in Oscoda, MI. In situ terminal electron accepting processes (TEAPs), contaminant composition and microbial phylogeny were studied at a plume transect 100 m downgradient of the source. The presence of reduced electron acceptors, relevant microbial communities, and elevated dissolved methane and carbon dioxide concentrations at the transect, as well as downgradient accumulation of BTEX metabolites and dechlorination products, indicated that past or current reductive dechlorination at the transect was likely driven by BTEX biodegradation in the methanogenic zone. However, TCE and toluene mineralization in sediment-groundwater microcosms without added electron acceptors did not exceed 5% during 300 days of incubation and was nearly invariant with original sediment TEAP, even following amendments of nitrogen and phosphorus. Mineralization rates were on the order of 0.0015-0.03 mumol/g day. After 8 months, microcosms showed evidence of methanogenesis, but CH4 and CO2 production arose from the degradation of contaminants other than toluene. Cis-dichloroethylene was observed in only one methanogenic microcosm after more than 500 days. It appears likely that spatially and temporally dynamic redox zonation at the plume transect will prevent future sustained reductive dehalogenation of highly chlorinated solvents, for during the course of a year, the predominant TEAP at the highly contaminated water table shifted from methanogenesis to iron- and sulfate-reduction. It is recommended that biotransformation studies combine considerations of long-term, spatially relevant changes in redox zonation with laboratory-scale studies of electron donor utilization and cometabolic substrate transformation to yield a more accurate assessment of natural bioattenuation of specific pollutants in aquifers contaminated by undefined organic waste mixtures.

Biotransformation↗
PubMed2001

In situ assessment of microbial sulfate reduction in a petroleum-contaminated aquifer using push-pull tests and stable sulfur isotope analyses.

Anaerobic microbial activities such as sulfate reduction are important for the degradation of petroleum hydrocarbons (PHC) in contaminated aquifers. The objective of this study was to evaluate the feasibility of single-well push-pull tests in combination with stable sulfur isotope analyses for the in situ quantification of microbial sulfate reduction. A series of push-pull tests was performed in an existing monitoring well of a PHC-contaminated aquifer in Studen (Switzerland). Sulfate transport behavior was evaluated in a first test. In three subsequent tests, we injected anoxic test solutions (up to 1000 l), which contained 0.5 mM bromide (Br-) as conservative tracer and 1 mM sulfate (SO4(2-)) as reactant. After an initial incubation period of 42.5 to 67.9 h, up to 1100 l of test solution/groundwater mixture was extracted in each test from the same location. During the extraction phases, we measured concentrations of relevant species including Br-, SO4(2-) and sulfide (S(-II)), as well as stable sulfur isotope ratios (delta 34S) of extracted, unconsumed SO4(2-) and extracted S(-II). Results indicated sulfate reduction activity in the vicinity of the test well. Computed first-order rate coefficients for sulfate reduction ranged from 0.043 +/- 0.013 to 0.130 +/- 0.015 day-1. Isotope enrichment factors (epsilon) computed from sulfur isotope fractionation of extracted, unconsumed SO4(2-) ranged from 20.2 +/- 5.5@1000 to 22.8 +/- 3.4@1000. Together with observed fractionation in extracted S(-II), isotope enrichment factors provided strong evidence for microbially mediated sulfate reduction. Thus, push-pull tests combined with stable sulfur isotope analyses proved useful for the in situ quantification of microbial sulfate reduction in a PHC-contaminated aquifer.

Biodegradation, Environmental↗
PubMed2002

Development and verification of a screening model for surface spreading of petroleum.

Overflows and leakage from aboveground storage tanks and pipelines carrying crude oil and petroleum products occur frequently. The spilled hydrocarbons pose environmental threats by contaminating the surrounding soil and the underlying ground water. Predicting the fate and transport of these chemicals is required for environmental risk assessment and for remedial measure design. The present paper discusses the formulation and application of the Oil Surface Flow Screening Model (OILSFSM) for predicting the surface flow of oil by taking into account infiltration and evaporation. Surface flow is simulated using a semi-analytical model based on the lubrication theory approximation of viscous flow. Infiltration is simulated using a version of the Green and Ampt infiltration model, which is modified to account for oil properties. Evaporation of volatile compounds is simulated using a compositional model that accounts for the changes in the fraction of each compound in the spilled oil. The coupling between surface flow, infiltration and evaporation is achieved by incorporating the infiltration and evaporation fluxes into the global continuity equation of the spilled oil. The model was verified against numerical models for infiltration and analytical models for surface flow. The verification study demonstrates the applicability of the model.

Disasters↗
PubMed2003

Biodegradation of petroleum hydrocarbon vapors: laboratory studies on rates and kinetics in unsaturated alluvial sand.

Predictions of natural attenuation of volatile organic compounds (VOCs) in the unsaturated zone rely critically on information about microbial biodegradation kinetics. This study aims at determining kinetic rate laws for the aerobic biodegradation of a mixture of 12 volatile petroleum hydrocarbons and methyl tert-butyl ether (MTBE) in unsaturated alluvial sand. Laboratory column and batch experiments were performed at room temperature under aerobic conditions, and a reactive transport model for VOC vapors in soil gas coupled to Monod-type degradation kinetics was used for data interpretation. In the column experiment, an acclimatization of 23 days took place before steady-state diffusive vapor transport through the horizontal column was achieved. Monod kinetic parameters Ks and vmax could be derived from the concentration profiles of toluene, m-xylene, n-octane, and n-hexane, because substrate saturation was approached with these compounds under the experimental conditions. The removal of cyclic alkanes, isooctane, and 1,2,4-trimethylbenzene followed first-order kinetics over the whole concentration range applied. MTBE, n-pentane, and chlorofluorocarbons (CFCs) were not visibly degraded. Batch experiments suggested first-order disappearance rate laws for all VOCs except n-octane, which decreased following zero-order kinetics in live batch experiments. For many compounds including MTBE, disappearance rates in abiotic batch experiments were as high as in live batches indicating sorption. It was concluded that the column approach is preferable for determining biodegradation rate parameters to be used in risk assessment models.

Biodegradation, Environmental↗
PubMed2003

Nitrate-consuming processes in a petroleum-contaminated aquifer quantified using push-pull tests combined with 15N isotope and acetylene-inhibition methods.

Nitrate consumption in aquifers may result from several biogenic and abiotic processes such as denitrification, assimilatory NO3- reduction, dissimilatory NO3- reduction to ammonium (DNRA), or abiotic NO3- (or NO2-) reduction. The objectives of this study were to investigate the fate of NO3- in a petroleum-contaminated aquifer, and to assess the feasibility of using single-well push-pull tests (PPTs) in combination with 15N isotope and C2H2 inhibition methods for the quantification of processes contributing to NO3- consumption. Three consecutive PPTs were performed in a monitoring well of a heating oil-contaminated aquifer in Erlen, Switzerland. For each test, we injected 500 l of test solution containing 0.5 mM Br- as conservative tracer and either 0.5 mM unlabeled NO3- or approximately 0.3 mM 15N-labeled NO3- as reactant. Test solutions were sparged during preparation and injection with either N2, Ar or 10% C2H2 in Ar. After an initial incubation period of 1.5-3.2 h, we extracted the test solution/groundwater mixtures from the same location and measured concentrations of relevant species including Br-, NO3-, NO2-, N2O, N2, and NH4+. In addition, we determined the 15N contents of N2, N2O, NH4+, and suspended biomass from 15N/14N isotope-ratio measurements. Average total test duration was 50.5 h. First-order rate coefficients (k) were computed from measured NO3- consumption, N2-15N production and N2O-15N production. From measured NO3- consumption we obtained nearly identical estimates of k for all PPTs with small 95% confidence intervals, indicating good reproducibility and accuracy for the tests. Estimates of k from N2-15N production and N2O-15N production indicated that denitrification accounted for only 46-49% of observed NO3- consumption. Production of N2-15N in the presence of C2H2 was observed during one of the tests, which may be an indicator for abiotic NO3- reduction. Moreover, 15N isotope analyses confirmed occurrence of assimilatory NO3- reduction (0.58 at.% 15N in suspended biomass) and to a smaller extent DNRA (up to 4 at.% 15N in NH4+). Our results indicated that the combination of PPTs, 15N-isotope and C2H2 inhibition methods provided improved information on denitrification as well as alternative fates of NO3- in this aquifer.

Acetylene↗
PubMed2003

A comparison of polycyclic aromatic hydrocarbon and petroleum hydrocarbon uptake by mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) in Hong Kong coastal waters.

The ability of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) to accumulate polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons (PHCs) from five sites in Hong Kong's coastal waters was compared. Mussels consistently had higher levels of contaminants, but their utility was limited at one highly polluted site due to mortality. Mussels and SPMDs ranked sites differently in terms of individual contaminant levels. Although SPMDs overcome many of the disadvantages of using living organisms to measure contaminants in marine waters, they cannot be used as "mimics" due to different PAH and PHC accumulation patterns.

Absorption↗
PubMed2003

Viability of natural attenuation in a petroleum-contaminated shallow sandy aquifer.

This study focused on evaluating and quantifying the potential of natural attenuation of groundwater at a petroleum-contaminated site in an industrial area of a satellite city of Seoul, Korea. Groundwater at the study site was contaminated with toluene, ethylbenzene and xylene (TEX). Eight rounds of groundwater sampling and subsequent chemical analyses were performed over a period of 3 years. The groundwater quality data suggests that TEX concentrations at this site have been decreasing with time and that the TEX plume is at a quasi-steady state. Trend analysis, changes in mass flux and plume area also confirmed that the TEX plume has reached a quasi-steady state. The proportion of the total attenuation attributable to biodegredation has decreased over the monitoring period while contribution of other attenuating processes, such as dilution or dispersion, has increased. Based on the calculated attenuation rates, it would take more than 20 years to clean up the site by natural attenuation alone.

Biodegradation, Environmental↗
PubMed2002

Community reappraisal of the perceived health effects of a petroleum refinery.

This paper presents results from a study of the community health impacts of a petroleum refinery in Oakville, Ontario in Canada. The research is informed by the environmental stress and coping literatures and the focus is on community reappraisal of the refinery's impacts before and after the implementation of a substantive odour reduction initiative on the part of the refinery operators. Community health surveys were conducted in 1992 (n = 391) and 1997 (n = 427) to examine changes in odour perception and annoyance and self-reported health status attributable to the odour reduction plan. The findings reported here suggest an on-going process of cognitive reappraisal, whereby negative perceptions and concerns decreased between 1992 and 1997. Irrespective of this positive reappraisal of the refinery efforts, those living close to the refinery continue to report negative health impacts. A strong mediating effect of odours on the refinery exposure-symptom reporting relationship was confirmed by our results. While the relationship between odour perception and symptom reporting indicates the importance of odour perception and annoyance as the principal mechanism mediating ill-health reporting, the plausibility of other causal pathways is recognized. Residents' sensitivity to the negative effects of the refinery on their health and the health of their children suggests a psychosocial reaction to the environmental stress associated with perceived and actual refinery emissions.

Adolescent↗
PubMed2000

A longitudinal study of the health impacts of a petroleum refinery.

Emissions from a petroleum refinery in Oakville, Ont., have been the source of longstanding health concerns among residents in the surrounding community. Between 1992 and 1997, the refinery implemented extensive odour reduction measures through improvements in waste water treatment, in sulphur recovery and combustion. In this paper, we present the main findings of a recent longitudinal analysis using data from community health surveys conducted in 1992 and 1997, before and after implementation of the odour reduction plan. The results show a decline in the frequency of odour perception and annoyance by residents whereas the reporting of cardinal and general symptoms among adults and children was virtually unchanged. Odour perception and annoyance were strongly related to symptom reporting in both years supporting the hypothesis that the effect of refinery emissions on residents' health is odour mediated. The findings extend our understanding of the psychosocial basis of symptom reporting in the vicinity of refineries.

Adult↗