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The pollution intensity of the Belay River was studied in different periods of petroleum refining processes over many years. The extent of river pollution was determined. The calculated complex indices for river pollution allow one to make hygienic ranging of the river by the basic hazard indices.
Epidemiologic historical cohort studies of petroleum refinery and chemical manufacturing workers in Texas were reviewed to examine their cancer mortality in comparison to the U.S. and to assess the possible impact of cancer mortality among these workers on the State of Texas as a whole. Summary standardized mortality ratios and 95% confidence intervals were calculated for 20 cancer types, taking into account the heterogeneity of individual studies. There were 4314 cancer deaths among the 92,318 workers employed in 10 independent plant populations. Overall, there was a significant deficit in cancer mortality among petrochemical workers compared with the general U.S. population (SMR = 88, 95% CI = 80 to 96). Only the summary SMRs for brain cancer (SMR = 113, 95% CI = 96 to 133) and leukemias (SMR = 112, 95% CI = 94 to 130) approached statistical significance. Lung and liver cancer mortality excesses, noted for Texas as a whole, were decreased in these workers. Additional follow-up of these cohorts, their expansion to include minority and female workers, and additional study of possible occupational contributions to leukemia and brain cancer are recommended.
This work explores the possibility of Ag+ electrospray ionization mass spectrometry (ESI-MS) to determine the molecular weight distributions of non-boiling petroleum fractions. Information about the molecular weight distributions is needed for fundamental studies on the nature of heavy crude oils and bitumens and for the development of novel recovery and processing methods. The method does not depend on thermal processes for the introduction of the fractions into the gas phase of the mass spectrometer, which is a considerable advantage over most other ionization methods. The Ag+ electrospray mass spectra of the fractions analyzed by using a toluene/methanol/cyclohexane (60:28:12%) solvent system display bimodal distributions in the ranges m/z approximately 300 to approximately 3000 and m/z 3000 to approximately 20,000. The abundances of the high molecular weight peak distributions can be reduced by in-source collisional activation experiments. Comparisons with the results obtained for model heteroatom-containing compounds (molecular weight < 600 Da) and high molecular weight polystyrene standards (up to one million Da) indicate that the majority of the structures in the saturate, naphthenoaromatic and polar aromatic fractions, and a significant portion of the asphaltenes, are small molecules. However, a considerable portion of the asphaltenes and some portion of the other fractions contain high molecular weight structures bound by covalent or strong non-covalent bonds. The results obtained by the Ag+ ESI method in this study for the saturate, aromatic, and polar fractions in a bitumen are in qualitative agreement with published molecular weight average results obtained for Cold Lake bitumen fractions analyzed by conventional gel permeation chromatography and field desorption mass spectrometry. Further work is needed to study the nature of the bonds and the interactions of the molecules in the asphaltene fractions by Ag+ ESI-MS.
Red swamp crayfish (Procambarus clarkii) were placed for a period of 7 days in Bayou Trepagnier, a Louisiana waterway which received petroleum-laden effluents from a manufacturing complex several decades ago. However, coolant water from the plant continued to be released into the bayou until 1995. Analyses of sediments at the exposure site revealed heavy contamination by lead, chromium, and copper, while concentrations of arsenic and cadmium were very low. Significant bioaccumulation of lead was observed in the hepatopancreas and gills of 7-day-exposed crayfish, whereas chromium accumulated the most in the gills and blood. Concentrations of copper in the crayfish did not change during the course of the study, suggesting that this essential metal constituent of the respiratory pigment is successfully regulated even when crayfish are exposed to relatively high levels of copper in the sediments. There was no metal accumulation in the abdominal muscle of the crayfish. That damage to the hepatopancreas occurred during the exposure is suggested by histopathological studies which revealed swollen and vacuolated R cells and an increase in the pH of the digestive juices. Blood glucose levels, as well as ovarian and hepatopancreatic indices, were unchanged. This study demonstrates that accumulation of nonessential metals in crayfish tissues in a wetland environment contaminated by mixed pollution (metals and hydrocarbons) reflects the concentrations of metals in the sediment.
Concern with environmental issues such as global climate change has stimulated research into the development of more environmentally friendly technologies and energy sources. One critical area of our economy is liquid transportation fuels. This article presents the results of the biodegradability potential of newly developed engineered fuels and compares the results to the biodegradability of conventional fuels and alternative fuels in current use. Biodegradability potential was determined under both aerobic and anaerobic conditions. Fuels that have a high degree of components derived from renewable sources proved to have a higher degradability potential than those composed of petroleum components.
To characterize petroleum products, a method based on the combination of IR-spectrometric structural group analysis, GC-simulated boiling analysis and multivariate regression techniques (PLS, PCR) has been developed. The best performance was achieved by a PLS regression model with six aliphatic and aromatic structural groups. Thereby, structural group distribution related to the boiling temperature could be obtained in order to quantify product-specific distribution parameters and to control material-conversion processes caused by biodegradation.
A procedure for the direct GFAAS determination of Ni in petroleum samples using a solid sampling strategy is proposed. Palladium was used as conventional modifier. Central composite design multivariate optimization defined the optimum temperature program and the Pd mass, allowing calibration using aqueous analytical solution. The limit of detection (LOD) at the optimized conditions was 0.23 ng of Ni, for typical sample masses between of 0.10 and 0.60 mg. Linearity at least up to 11 ng of Ni and a characteristic mass of 45 pg were observed, defining a dynamic range between 0.52 and 110 microg g(-1). Typical coefficients of variation (n = 10) in the analysis of oil reference materials were 7%. Method validation was performed both by the analysis of oil certified reference materials and by comparison with an independent method (ASTM 5863-B). No statistically significant difference was observed between obtained and expected values. The total determination cycle lasted 5 min, equivalent to a sample throughput of 6 h(-1) for duplicate determinations.
A method is proposed for determination of toxicokinetic parameters for bioconcentration by phytoplankton of the water-soluble fraction (WSF) of petroleum hydrocarbon (PH) associated with No. 0 diesel, in which WSF-PH concentration in phytoplankton cells, C(A(d)), is estimated by subtracting concentration in water (S-bottle) containing a phytoplankton sample from that in a C-bottle without phytoplankton. It was demonstrated that C(A(d)) agrees well with the concentration found by direct ultrasonication extraction of collected cells, C(A(ind)) ( r = 0.88, p < 0.0001), and its uncertainty was about 17.6%. Mesocosms in 25-m3 ethylene vinyl acetate or 4-m3 polyethylene bags were performed at two sites in China: Changjiang Estuary in spring/summer 1998 and Jiaozhou Bay in autumn 1999 and spring/summer 2000. The experiments were designed to determine toxicokinetic parameters, including specific rates of uptake and elimination, and bioconcentration factor (BCF), for bioconcentration of WSF-PH by phytoplankton. A modified kinetic two-compartment model for bioconcentration of WSF-PH by phytoplankton was developed to estimate the toxicokinetic parameters. In the model, the influence of phytoplankton growth on bioconcentration and WSF-PH decline due to biotic and abiotic processes other than bioconcentration, such as volatilization, microbial degradation, phytolysis, and sorption expressed as an exponential-decay equation, are taken into account. Size-dependent BCF was observed in the laboratory experiment. BCFs were 1.0 x 10(4) in summer in Changjiang Estuary, 1.6 x 10(4) in summer, and 1.1 x 10(4) in autumn in Jiaozhou Bay. The difference in BCF may be interpreted by its size dependence.
Abstract A multidisciplinary field study investigating the fate and transport of petroleum hydrocarbons commonly associated with jet-fuel contamination is currently underway at Columbus Air Force Base (AFB), Mississippi. Sixty sediment cores from 12 boreholes were recovered from the study aquifer. The goal of this initial sampling was to characterize the potential microbial activity using 14C-labeled substrates, as well as the presence, abundance, and distribution of specific hydrocarbon degrading genotypes using DNA:DNA hybridization. Enumeration of total microbial abundance using a 16S rDNA universal oligonucleotide probe was compared to traditional enumeration methods. Total culturable populations determined by spread plate analysis ranged from a low of 10(4) to more than 10(6) organisms per gram sediment. Microbial abundance estimated by DNA hybridization studies with 16S rDNA genes ranged from 10(7) to 10(8) organisms per gram sediment. Molecular analysis of aquifer samples using DNA probes targeting genes encoding the degradative enzymes alkane hydroxylase (alkB), catechol 2,3-dioxygenase (nahH), naphthalene dioxygenase (nahA), toluene dioxygenase (todC1C2), toluene monooxygenase (tomA), and xylene monooxygenase (xylA), as well as two probes measuring methanogenic microorganisms, codh (carbon monoxide dehydrogenase) and mcr (methyl coenzyme reductase), revealed that each target gene sequence was present in nearly all 60 samples. The presence of organisms demonstrating the phenotype to degrade BTEX and naphthalene was further supported using mineralization assays with 14C-labeled benzene, toluene, naphthalene, and phenanthrene. Minimal activity occurred during the first 24 hours. After a period of 5-7 days, greater than 40% of the target compounds were mineralized in aquifer sediments.
Two methods for extraction and determination of benzo[a]pyrene and other PAH in liquid and white soft paraffins, widely used for medicinal and cosmetic purposes, are compared. A method based on extraction by frontal elution chromatography, column and thin-layer chromatography and final spectrophotofluorometric determination gave the best results in the determination of the very low levels (ng/g) of PAH present in these fully refined samples. The complete analytical procedure showed an acceptable percentage of recoveries and good applicability to routine analysis of the PAH content in these petroleum products for the proper evaluation of their potential hazards to human health.
Incomplete combustion of kerosene heater, and fuel gas and liquefied petroleum gas-burner emissions produces indoor pollutants that may be carcinogenic. The incomplete-combustion products from each type of appliance were therefore collected by adsorption on about 3 g of XAD-2 resin, and were extracted with benzene-methanol as a solvent for determination and identification of mutagens in the Salmonella-microsome test system. Benzene-methanol extracts of the particulates generated by a heater and two burners showed extreme mutagenicity for strains TA97 and TA98 without S9 mix. Based on the results of analysis, a combination of high performance liquid chromatography (h.p.l.c.) and gas chromatography (GC), about 40-80% of the direct-acting mutagenicity in each crude extract showed the same h.p.l.c. and GC retention times as dinitropyrenes (1,3-, 1,6- and 1,8-isomers), and 1-nitropyrene. Moreover, other nitroarenes, 2-nitrofluorene, 1,5- and 1,8-dinitronaphthalene, and 4,4'-dinitrobiphenyl, were detectable in almost all samples, but their contribution to the mutagenicity of each extract was very low. Kerosene heaters were found to generate small amounts (0.2 ng/h) of dinitropyrenes, which are potential mutagens/carcinogens, only after 1 h of operation.
Biological treatment of petroleum refinery wastewater was studied in a rotating biological contactor (RBC) coupled to a polyurethane foam (PUF) as a porous biomass support. The PUF was attached on both sides of biodisks. The biodegradation studies were carried out at varying hydraulic and organic loadings. COD removal efficiency of up to 87% was achieved. The results obtained in terms of biodegradation of COD, NH3-N, phenol, hydrocarbons and suspended solids in this study were compared with those in the literature. The RBC-PUF bioreactor was found to have a better performance than a conventional RBC for the biodegradation of the above mentioned parameters. A higher concentration of active biomass (77 g TVS/m2) was observed in the RBC-PUF as compared to other treatment systems. A linear relationship between COD applied and COD removed was observed for the combined four stage system as well as for the individual stages.
The concentrations of total petroleum hydrocarbons (TPH) were determined in nearshore sediment samples collected from 28 sampling sites along the United Arab Emirates shorelines on the Arabian Gulf, the Gulf of Oman and seven major creeks (khors) extending from them. Concentrations were highly variable and ranged between <0.4 and 212 microg g(-1) dry weight, and the highest values obtained were in the top sediment (1 cm) layer near a fuel filling station and port areas. Locally high levels of TPH were found in Dubai, Sharjah and Ajman semi-enclosed creeks where boat activities and land-based wastewater discharges are most common. Data support the premise that port activities, fuel filling stations and land-based wastewater discharges are major sources of pollution in the study area. Correlations with sediment grain size, total organic carbon (TOC) and distance from pollution sources are discussed.
A coal tar pitch and a petroleum vacuum residue have been separated by TLC using pyridine, acetonitrile, toluene and pentane to develop the chromatograms. The bands of material detected were recovered in 1-methyl-2-pyrrolidinone (NMP) solvent and examined by size-exclusion chromatography (SEC) in NMP eluent. The relation between elution time in SEC and mobility on the TLC plate indicated that molecular size increased steadily with increasing immobility on the plate. This relation was reinforced by UV fluorescence spectroscopy in that the fluorescence moved to longer wavelengths with increasing immobility. The molecular size of the material excluded from the porosity of the SEC column remains undefined; some excluded material was found in all of the fractions from both samples. The valley of zero intensity separating the retained material from the excluded material may suggest a change of structure from near-planar in the retained region to three-dimensional in the excluded region.
In this work, a new family of branched poly(ethylene oxide-propylene oxide) (PEO-PPO) block copolymers designed as TETRONIC polyols is evaluated and compared to linear PEO-PPO block copolymers designed as PLURONIC polyols. Additives have been employed as well in order to improve solubility of these materials in aqueous solution. Such additives include the sodium p-toluene sulfonate (NaPTS) hydrotrope and concentrated hydrochloric acid. Solubility tests and aqueous solution surface tension data showed consistent results: the structure of the block PEO-PPO copolymers exerts a huge influence on their solubility in water. The solubility of such copolymers is increased by the presence of the sodium toluene sulfonate (NaPTS) hydrotrope. The presence of HCl caused increased solubility for the copolymer TETRONIC polyol only, the effect being less than that observed for the hydrotrope. It is concluded that as regards emulsion stabilization, TETRONIC copolymer polyols perform better. Correlation between structure and properties leads to the optimization of block PEO-PPO copolymer selection aiming at using these materials for the separation of petroleum industry emulsions.
A model is proposed to account for the interaction energy and adhesion force between petroleum asphaltenes and metallic surfaces. It is assumed that the total molecule-surface interaction potential may be constructed through superposition of corresponding interactions with a relevant number of atomic layers forming the substrate and resorting to the Lindhard continuum planar potential (CPP) approximation, which requires only of knowledge of binary molecule-atom interactions. Molecular mechanics (MM) calculations are performed to generate the average binary interaction between the asphaltene molecule and an atom in the substrate, which in turn is represented by a parameterized analytical--physically sound--expression. The resulting CPP yields an analytical expression representing the interaction between the asphaltene molecule and each substrate layer. To validate the method, pilot calculations are performed for a sample asphaltene molecule with a fixed orientation relative to metallic surfaces of iron, aluminum, and chromium. Comparison between corresponding CPP and MM calculations for the asphaltene-plane (A-P) and asphaltene-substrate (A-S) interactions indicate reasonable agreement pointing to the adequacy of the CPP method to represent molecule-surface interactions. Also, the effect of a surrounding (i.e., solvent) medium is addressed with the use of a dielectric constant, epsilon, incorporated in the molecule-atom potential. Finally, a discussion is presented on the applicability of the method to generate an analytical universal expression for asphaltene-metallic wall interactions.
Euphorbia tirucalli L., known as the petroleum plant, produces a large amount of triterpenes, such as beta-amyrin. Degenerate RT-PCR based on the sequences conserved among known beta-amyrin synthases led to cloning of a putative triterpene synthase cDNA, EtAS, from leaves of E. tirucalli. The deduced amino acid sequence of the EtAS cDNA showed the highest identity of 82% to the Panax ginseng beta-amyrin synthase. Heterologous expression of the EtAS ORF in the methylotrophic yeast, Pichia pastoris, resulted in production of beta-amyrin, revealing that the EtAS cDNA codes for a beta-amyrin synthase. This is the first report of a gene involved in the triterpene synthetic pathway from Euphorbiaceae plants.
A comprehensive hydro-geochemical characterization was carried out in a petroleum-contaminated shallow sandy aquifer in South Africa. The results indicate the presence of a BTEX (benzene, toluene, ethylbenzene, and xylene) plume that has moved, although only slightly, along the regional hydraulic gradient from the spill site. Associated with the contaminant plume, spatial distribution pattern of terminal electron acceptors and metabolites indicates simultaneous occurrence of nitrate, manganese, iron and sulfate reductions resulting in overlapping redox zones within the aquifer. From the measured concentration of metabolic by-products, sulfate and iron reductions seem to be the dominant metabolic pathways, though. Incubation experiments conducted with hydrocarbon contaminated aquifer sediments and inherent microbial assemblages provide a sulfate reduction rate of 4272 nmol cm(-3) day(-1) and 96 nmol cm(-3) day(-1) for winter and summer, respectively. As oppose to this, iron reduction dominates in summer with measured respiration rate of 1414 nmol cm(-3) day(-1). In winter iron reduction was measured to be only 24 nmol cm(-3) day(-1). Based on the dissimilatory iron and sulfate reduction rate measurements, we predict that at the aquifer site, intrinsic BTEX oxidation is primarily occurring in winter and is coupled to sulfate reduction. Although widespread in the aquifer, the contribution of iron reduction for the removal of aromatic monocyclic hydrocarbons is relatively minor.