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PubMedDate not supplied

Statistical evaluation of geochemical parameter distribution in a ground water system contaminated with petroleum hydrocarbons.

A shallow-depth ground water area was investigated to identify the dominant processes governing the distribution of hydrocarbon contaminants and hydrogeochemical parameters. The ground water in the study site has been highly contaminated with petroleum hydrocarbons. A preliminary pump-and-treatment remediation technology was applied for 4 yr at the site. Multivariate analyses were applied to hydrogeochemical data obtained before and after the rainy season. The pump-and-treatment application, indigenous biodegradation, and mixing by precipitation recharge are the major factors or events involved in the distribution of geochemical parameters of the ground water in the study area. Site-specific artificial pavement also played an important role in the evolution of the ground water chemistry. A conventional graphical analysis method (Piper plot) of major ions did not effectively reveal these effects. In this study, we demonstrate the usefulness of multivariate analysis (factor and cluster analyses) using biodegradation indicator parameters, as well as major cations and anions, for the study of the ground water system in the hydrocarbon-contaminated site.

Biodegradation, Environmental↗
PubMedDate not supplied

Relationship between water repellency and native and petroleum-derived organic carbon in soils.

Some soils develop severe and persistent water repellency following contamination with crude oil. This study was conducted to characterize and compare the spatial distribution of soil water repellency and residual oil contamination at 12 such sites. The molarity of ethanol droplet (MED) test was used to assess soil water repellency and the content of dichloromethane-extractable organics (DEO) was used to quantify residual oil in soil. We found a relatively strong positive correlation between MED and DEO in soil (r2 = 0.74). Both variables tended to decrease abruptly with depth at 11 of the 12 study sites. Dichloromethane-extractable organics similarly decreased with depth in control adjacent soil (MED = 0 M), but from an average concentration one to two orders of magnitude lower than in water-repellent soil. Using data from corresponding control adjacent and water-repellent soils, we determined that approximately 29 and 10% of measured total organic carbon in water-repellent A- and B-horizon soil, respectively, consists of dichloromethane-insoluble organic carbon of petroleum origin. We propose that this fraction contains most of the causative agents of soil water repellency at the studied sites.

Carbon↗
PubMed2006

Occurrence and rates of terminal electron-accepting processes and recharge processes in petroleum hydrocarbon-contaminated subsurface.

The occurrence and rates of terminal electron acceptor processes, and recharge processes in the unsaturated zone of a boreal site contaminated with petroleum hydrocarbons in the range C(10) to C(40) were examined. Soil microcosms were used to determine the rates of denitrification, iron (Fe) reduction, sulfate (SO(4)) reduction, and methanogenesis in two vertical soil profiles contaminated with oil, and in a noncontaminated reference sample. Furthermore, the abundances of the 16S rRNA genes belonging to Geobacteracaea in the samples were determined by real-time quantitative polymerase chain reaction (PCR). Analyses of ground water chemistry and soil gas composition were also performed together with continuous in situ monitoring of soil water and ground water chemistry. Several lines of evidence were obtained to demonstrate that both Fe reduction and methanogenesis played significant roles in the vertical profiles: Fe reduction rates up to 3.7 nmol h(-1) g(-1) were recorded and they correlated with the abundances of the Geobacteracaea 16S rRNA genes (range: 2.3 x 10(5) to 4.9 x 10(7) copies g(-1)). In the ground water, ferrous iron (Fe(2+)) concentration up to 55 mg L(-1) was measured. Methane production rates up to 2.5 nmol h(-1) g(-1) were obtained together with methane content up to 15% (vol/vol) in the soil gas. The continuous monitoring of soil water and ground water chemistry, microcosm experiments, and soil gas monitoring together demonstrated that the high microbial activity in the unsaturated zone resulted in rapid removal of oxygen from the infiltrating recharge thus leaving the anaerobic microbial processes dominant below 1.5 m depth both in the unsaturated and the saturated zones of the subsurface.

Anaerobiosis↗
PubMed2006

Application of monitored natural attenuation to remediate a petroleum-hydrocarbon spill site.

Contamination of groundwater by petroleum-hydrocarbons is a serious environmental problem. The Monitored Natural Attenuation (MNA) approach is a passive remediation to degrade and dissipate groundwater contaminants in situ. In this study, a full-scale natural bioremediation investigation was conducted at a gasoline spill site. Results show that concentrations of major contaminants (benzene, toluene, ethylbenzene, and xylenes) dropped to below detection limit before they reached the downgradient monitor well located 280 m from the spill location. The results also reveal that natural biodegradation was the major cause of the observed contaminant reduction. The calculated natural first-order attenuation rates for BTEX and 1,2,4-trimethylbenzene (1,2,4-TMB) ranged from 0.051 (benzene) to 0.189 1/day (1,2,4-TMB). Evidence for the occurrence of natural attenuation includes the following: (1) depletion of dissolved oxygen, nitrate, and sulfate; (2) production of dissolved ferrous iron, sulfide, and CO2; (3) decreased BTEX concentrations and BTEX as carbon to TOC ratio along the transport path; (4) increased alkalinity and microbial populations; (5) limited spreading of the BTEX plume; and (6) preferential removal of certain BTEX components along the transport path. Additionally, the biodegradation capacity (44.73 mg/L) for BTEX and 1,2,4-TMB was much higher than other detected contaminants within the plume. Hence, natural attenuation can effectively contain the plume, and biodegradation processes played an important role in contaminant removal.

Benzene Derivatives↗
PubMed1999

Calculation of human health risk-based screening levels (RBSLs) for petroleum.

Hazardous waste site managers and regulators can decide easily whether site contamination requires remediation to protect human health, but defining the extent of cleanup is often an enormous challenge. When is the site clean enough for human access and use? Risk assessment tools can be used to help answer this question. One can calculate chemical-specific risk-based screening levels (RBSLs) in environmental media (e.g. soil, water, and food) that correspond to "acceptable" levels of risk. RBSLs can be calculated for individual chemicals and chemical mixtures, specific to various exposure pathways. In calculating RBSLs, one must account for the fact that people may be exposed to more than one chemical by more than one exposure pathway. Fate and transport models may be needed to predict how people might become exposed to site contamination in the future. Examples RBSLs for non-cancer effects are calculated to illustrate the utility and limitations of RBSLs for making risk-based decisions at petroleum release sites.

Carcinogens↗
PubMed1994

Associations between safety and contingency measures and occupational accidents on offshore petroleum platforms.

OBJECTIVES: The primary purpose of this study was to determine the association between organizational factors and accidents among employees on the Norwegian continental shelf. METHODS: A self-administered survey among offshore petroleum personnel was conducted in the spring of 1990. The survey drew respondents from five companies and eight platforms. The response rate was 92% (N = 915). RESULTS: Substantial correlations were found between management and employee commitment and involvement in safety work, social support, attitudes towards safety measures, the personnel's satisfaction-dissatisfaction with the safety and contingency measures and accident frequency. CONCLUSIONS: Employee satisfaction-dissatisfaction was associated with injury rates, and also with other organizational factors. The credibility of the theory that employee perception of safety and contingency measures mirrors the status of accident prevention work was enhanced.

Accidents, Occupational↗
PubMed1994

Associations between organizational factors and safety and contingency measures on offshore petroleum platforms.

OBJECTIVES: The study determined the associations between organizational factors and safety and contingency measures among employees on the Norwegian continental shelf. METHODS: A self-administered survey among offshore petroleum personnel was conducted in the spring of 1990. The survey drew respondents from five companies and eight installations. The response rate was 92% (N = 915). RESULTS: Substantial correlations were found between management and employee commitment and involvement in safety work, social support, attitudes towards safety measures, and the personnel's satisfaction-dissatisfaction with the safety and contingency measures. CONCLUSIONS: Employee perceptions of greater management commitment, social support, and subjective evaluations of priorities of safety versus production goals were all important predictor variables for employee satisfaction with safety and contingency measures.

Accident Prevention↗
PubMed1987

Associations between several sites of cancer and twelve petroleum-derived liquids. Results from a case-referent study in Montreal.

A population-based case-referent study provided information on the associations between several types of cancer and 12 petroleum-derived liquids. All site-exposure combinations were investigated. The most interesting results concerned the following combinations: leaded gasoline-stomach cancer, aviation gasoline-kidney cancer (and the possible implications of this association for a similar effect of unleaded automotive gasoline), mineral spirits-squamous-cell cancer of the lung, diesel fuel-nonadenocarcinoma lung cancer, lubricating oils-squamous-cell lung cancer, cutting fluids-bladder cancer, other mineral oils-bladder cancer, mineral spirits-prostate cancer, diesel fuel-prostate cancer, and lubricating oils-prostate cancer.

Humans↗
PubMed1984

"Health Watch": the Australian petroleum industry health study surveillance programme.

A surveillance system, capable of linking experience in specific jobs with certain health outcomes, has been established within the Australian petroleum industry. A defined population of 11 596 employees has been assembled, after personal interviews. Events recorded are death and its cause, and diagnosis of cancer. Members of the study population are followed up after leaving the industry. By the end of 1983, 33 deaths had occurred, fewer than would be expected from the prevailing rates in the general Australian population. With progressive accumulation of follow-up data, questions of greater complexity will be addressed.

Adolescent↗
PubMed1987

Current mortality in the Australian petroleum industry: the healthy-worker effect and the influence of life-style factors.

A surveillance system, to monitor mortality and cancer morbidity on a continuing basis, has been established in the Australian petroleum industry. A baseline survey of 11,573 employees, by personal interview, was carried out in 1981-1983. By the end of June 1986, 33,712 person-years of observation in men had accrued, with 109 deaths. Standardized mortality ratios, with the Australian national death rates as reference, indicate that in terms of mortality from all causes and in mortality from the more common diseases, the death rates in this population are substantially lower than in the national population. Standardization was also carried out in the case of employed men, with data from contributors to the Commonwealth superannuation fund as reference, in order to provide a more appropriate contrast. The risks of tobacco smoking are demonstrated, as is the probable protective effect of mild-to-moderate alcohol consumption. The advantages to the occupational physician in being able to describe current mortality patterns, and in being able to delineate "at-risk" groups are discussed, particularly in the context of health promotion and other interventions.

Alcohol Drinking↗
PubMed1983

Residues of petroleum hydrocarbons in tissues of sea turtles exposed to the Ixtoc I oil spill.

Sea turtles found dead when the Ixtoc I oil spill reached Texas waters were necropsied and tissues were analyzed for residues of petroleum hydrocarbons. Two of three turtles were in poor flesh, but had no apparent oil-caused lesions. There was evidence of oil in all tissues examined and indications that the exposure had been chronic. Comparisons with results of studies done on birds indicate consumption of 50,000 ppm or more of oil in the diet. Some possible mechanisms of mortality are suggested.

Animals↗
PubMed1983

Administrative procedures and sanctions; questions and answers relating to the applicability to the petroleum violation escrow funds of regulations of the energy conservation programs--Department of Energy. Ruling.

The Department of Energy (DOE) Office of General Counsel issues the appended Ruling to respond to questions relating to the applicability to the petroleum violation escrow funds of the regulations of the energy conservation programs administered by DOE to which these funds can be distributed under Section 155 of the Further Continuing Appropriations Act, Fiscal Year 1983.

Conservation of Energy Resources↗
PubMed1999

Biodegradation of phenol by bacterial strains from petroleum-refining wastewater purification plant.

The ability of four strains of bacteria derived from a biological petroleum-refining wastewater purification plant to carry out the biodegradation of phenol was studied. Two of the strains belonging to the genus Pseudomonas were found to be characterised by high effectiveness of the removal of phenol which was used as sole carbon and energy source (the strains were designated P1 and P2). In turn the effect of inoculum size, initial concentration of substrate (500 and 1,000 mg phenol/L) and temperature (10, 20 and 30 degrees C) on the rate of phenol degradation by strains P1, P2 and mixture of both was investigated. It was found that strain P1 which was identified as Pseudomonas fluorescens degraded phenol better than strain P2--Pseudomonas cepacia. The rate of phenol biodegradation was significantly affected by size of inoculum and temperature of incubation. Phenol was removed the fastest with the highest inoculum used. The optimal temperature was about 20 degrees C. At 10 and 30 degrees C the process of biodegradation was visibly inhibited. The rate of phenol utilisation was also found to decrease with increased concentration of substrate.

Biodegradation, Environmental↗
PubMed2000

[Electrolyte homeostasis in petroleum industry workers].

Disorders in electrolyte balance of erythrocytes and plasma in petroleum industry workers are described. All examinees were divided into 3 groups with different intensity of chemical exposure: 1) workers of the plant without contacts with chemicals (21); 2) workers handling chemicals 2-3 times a week (28)--risk group; and 3) workers permanently exposed to chemicals for 3-5 years (46); control group consisted of 40 healthy subjects without occupational exposure to chemicals. Significant changes in erythrocyte and plasma electrolytes were detected in groups 2 and, more so, 3: erythrocyte K, Mg, and Ca levels were decreased and Na and P levels increased, while in the plasma K, Mg, and P concentrations were increased and Na and Ca decreased.

Adult↗
PubMed2001

Estimating mean exposures from censored data: exposure to benzene in the Australian petroleum industry.

A retrospective assessment of exposure to benzene was carried out for a nested case control study of lympho-haematopoietic cancers, including leukaemia, in the Australian petroleum industry. Each job or task in the industry was assigned a Base Estimate (BE) of exposure derived from task-based personal exposure assessments carried out by the company occupational hygienists. The BEs corresponded to the estimated arithmetic mean exposure to benzene for each job or task and were used in a deterministic algorithm to estimate the exposure of subjects in the study. Nearly all of the data sets underlying the BEs were found to contain some values below the limit of detection (LOD) of the sampling and analytical methods and some were very heavily censored; up to 95% of the data were below the LOD in some data sets. It was necessary, therefore, to use a method of calculating the arithmetic mean exposures that took into account the censored data. Three different methods were employed in an attempt to select the most appropriate method for the particular data in the study. A common method is to replace the missing (censored) values with half the detection limit. This method has been recommended for data sets where much of the data are below the limit of detection or where the data are highly skewed; with a geometric standard deviation of 3 or more. Another method, involving replacing the censored data with the limit of detection divided by the square root of 2, has been recommended when relatively few data are below the detection limit or where data are not highly skewed. A third method that was examined is Cohen's method. This involves mathematical extrapolation of the left-hand tail of the distribution, based on the distribution of the uncensored data, and calculation of the maximum likelihood estimate of the arithmetic mean. When these three methods were applied to the data in this study it was found that the first two simple methods give similar results in most cases. Cohen's method on the other hand, gave results that were generally, but not always, higher than simpler methods and in some cases gave extremely high and even implausible estimates of the mean. It appears that if the data deviate substantially from a simple log-normal distribution, particularly if high outliers are present, then Cohen's method produces erratic and unreliable estimates. After examining these results, and both the distributions and proportions of censored data, it was decided that the half limit of detection method was most suitable in this particular study.

Australia↗
PubMed2001

Peroxidase-catalyzed removal of phenols from a petroleum refinery wastewater.

The phenol content of a petroleum refinery wastewater was reduced below the discharge limit following treatment with horseradish peroxidase and H2O2. Approximately 58% of COD, 78% of BOD5, and 95% of toxicity were removed along with the phenols. As a result of treatment, phenols were transformed into less biodegradable compounds which could be removed by subsequent coagulation and precipitation. Optimization of the peroxide concentration led to 20% enzyme savings. The use of PEG and chitosan as protective additives resulted in 4 and 25-fold reductions in enzyme requirements, respectively. Phenol removal did not appear to be adversely affected by the presence of other hydrocarbons that are frequently present in refinery wastewaters.

Catalysis↗
PubMed2001

Impacts of crude oil on the germination and growth of cress seeds (Lepidium sp.) after bioremediation of agricultural soil polluted with crude petroleum using "adapted" Pseudomonas putida.

The impacts of crude oil on the germination, growth and morphology of cress seeds (Lepidium sp.) after bioremediation of agricultural soil polluted with crude petroleum using "adapted" Pseudomonas putida (PP) were examined for 15 days. At day 15 there was 100% germination in the untreated control samples, the mean height of the seedlings was 75.8 +/- 2.6 mm and all appeared to have grown morphologically normal. In the experimental samples treated with oil and PP inoculation, there was 98% germination and the seedlings reached a height of 63.8 +/- 6.9 mm; again, morphologically the seedlings appeared normal. However, in the control samples treated with oil but without PP inoculation, there was 31-38% germination and seedling heights of 34.2 +/- 11.4-42.3 +/- 8.5 mm with abnormal morphology. Treatment of oil-impacted agricultural soil with PP as a bioremediation agent does produce soil which is capable of growing larger and healthier plants than where bioremediation has not taken place.

Biodegradation, Environmental↗
PubMedDate not supplied

A cross-sectional study of workers with occupational exposure to petroleum derivatives.

Expression of human involucrin (hINV) a protein of the cornified cell envelope, was studied in the skin of gasoline storage workers, in order to evaluate the effects of the exposure to petroleum derivatives. A total of 25 forearm skin punch biopsies were carried out. Twenty of which were performed on exposed subjects and five on controls. The specimens were processed for immunohistochemistry and hINV expression was evaluated using an anti-hINV monoclonal antibody and the ABC technique. Percentage of immunolabeled keratinocytes was significantly higher in subjects exposed to gasoline with respect to the control sample. A premature hINV expression was detected both in suprapapillary and interpapillary keratinocytes. Such overexpression of hINV seems to be related to an attempt of increasing skin defence mechanism. Therefore it was concluded that also in absence of clinical skin manifestation the exposure to gasoline determines an involvement of keratinocytes on molecular basis.

Adult↗