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The task of the occupational physician can be greatly assisted by a knowledge of the manufacturing processes in which workers are engaged, the nature of the products that these processes produce, and the raw materials upon which they depend. Because this is particularly true of the petroleum industry, this chapter is devoted to a challenging overview of petroleum composition, analysis and refining technology.
Petroleum refinery workers are potentially exposed to a wide range of petroleum-derived hydrocarbons and chemical substances used in the manufacturing of petroleum derivatives. Benzene, toluene and xylene (BTX) are produced by distillation in the aromatics units and used as raw materials for petrol and petrochemical products. The aim of this study was to evaluate the genotoxic effects of occupational exposure to BTX in a petroleum refinery in the North of Portugal. The exposed group consisted of 48 workers from the aromatics plant and the control group consisted of 30 persons matched for various confounding factors. Chromosome aberrations (CA), micronuclei (MN), and DNA damage (evaluated by means of the comet assay) were measured in peripheral blood leukocytes. t,t-Muconic acid (t,t-MA), hippuric acid (HA) and methylhippuric acid (MHA) concentrations were measured in urine samples collected at the end of the workshift. The results suggest that occupational exposure to toluene and xylene is very low. A statistically significant increase in t,t-MA excretion was found in the exposed group although t,t-MA levels were found to be lower than the biological exposure index (BEI). Significant increases were found for CA, MN and comet tail length (TL) in the exposed group (p<0.05). No association was found between tobacco smoking and the effect biomarkers analysed. A positive association was found between CA and MN with age in the control group (p<0.05).
A soil with aged contamination from lubricating oil (LO) and polychlorinated biphenyls (PCBs) was treated in a bioslurry reactor to investigate in-soil biosurfactant production by Pseudomonas aeruginosa, the most abundant indigenous, culturable, hydrocarbon-degrading microorganism. After 2 days of growth on LO, a depletion of nitrogen stimulated the production and accumulation of rhamnolipids to levels roughly 20 times the critical micelle concentration. Surface tensions and concentrations of monorhamnolipid and dirhamnolipid, PCBs, and total petroleum hydrocarbons (TPH) were measured in a slurry filtrate. Soil-bound PCBs and TPH were also quantified. Rhamnolipid production was observed within 1 to 2 days after nitrogen depletion in each of the 10 batches tested. By day 6, total rhamnolipid concentrations increased from below detection to average values over 1,000 mg/L, which caused over 98% of soil-bound PCBs and over 99% of TPH to be emulsified and recovered in the filtrate. After 70 days, rhamnolipid concentrations were only reduced by 15%, because of nitrogen-limited rates of rhamnolipid biodegradation. The results show that in-soil biosurfactant production can be stimulated in a controlled way with nutrient limitation and can be used to achieve soil washing.
A thermophilic anaerobic bacterium, designated strain BMAT (T = type strain), was isolated from the production water of Beatrice oil field in the North Sea (United Kingdom). The cells were straight to bent rods (1 to 5 by 0.3 to 0.5 microns) which stained gram negative. Strain BMAT obtained energy from the reduction of manganese (IV), iron(III), and nitrate in the presence of yeast extract, peptone, Casamino Acids, tryptone, hydrogen, malate, acetate, citrate, pyruvate, lactate, succinate, and valerate. The isolate grew optimally at 60 degrees C (temperature range for growth, 50 to 65 degrees C) and in the presence of 2% (wt/vol) NaCl (NaCl range for growth, 0 to 5% [wt/vol]). The DNA base composition was 34 mol% G + C. Phylogenetic analyses of the 16S rRNA gene indicated that strain BMAT is a member of the domain Bacteria. The closest known bacterium is the moderate thermophile Flexistipes sinusarabici (similarity value, 88%). Strain BMAT possesses phenotypic and phylogenetic traits that do not allow its classification as a member of any previously described genus; therefore, we propose that this isolate should be described as a member of a novel species of a new genus, Deferribacter thermophilus gen. nov., sp. nov.
Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to >400 degrees C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. Heterocyclic sulfur compounds have been identified in high temperature zones and hydrothermal petroleums of the Guaymas Basin vent systems. They can be interpreted as being synthesized from formaldehyde and sulfur or HS kappa- in the hydrothermal fluids. Other products from potential synthesis reactions have not yet been found in the natural systems but are expected based on known industrial processes and inferences from experimental simulation data. Various industrial processes have been reviewed and are of relevance to hydrothermal synthesis of organic compounds. The reactivity of organic compounds in hot water (200-350 degrees C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to >400 degrees C.
PURPOSE: In order to improve our knowledge on the efficacy and safety of sunscreen products, we measured the skin penetration profiles of ultra-violet (UV) filters in vitro and in vivo, and the corresponding sun protection factors (SPF) from two vehicles (an O/W emulsion-gel and petroleum jelly). METHODS: The UV filters tested were oxybenzone (5%, A), 2-ethylhexyl 4-methoxycinnamate (7.5%,B), and 2-ethylhexylsalicylate (3%,C). Two mg/cm(2) were applied for 2 min to 6 h. In vitro penetration measurements were performed with static diffusion cells. In vivo, horny layer concentrations were measured after stripping and the SPF evaluated as recommended by the COLIPA-guidelines. RESULTS: Significant differences between vehicles were noticed in vitro as well as in vivo. In vitro, the emulsion-gel generated higher epidermal concentrations than petroleum jelly. Values at 6 h, expressed as percent of the applied dose for A, B, and C were 4, 9, and 7% for the emulsion-gel and 2, 1, and 2% for petroleum jelly. An opposite trend was noticed, mainly for A, in the deeper skin layers with concentrations of 2% in the dermis and 5% in the receptor fluid for petroleum jelly and 0.6% and 1% for the emulsion-gel respectively. In vivo, for each UV filter, maximal stratum corneum levels (15 strips) were obtained at 0.5 h with percentages of the applied doses of 50% for the emulsion-gel and 15 percent for petroleum jelly. SPFs, measured 0.5 h after application amounted to 14 for the emulsion-gel and 5 for petroleum jelly, and decreased in both cases by a factor 2.2 after removal of non penetrated product. CONCLUSIONS: These preliminary results demonstrated that UV filters penetration and retention as well as expected SPF could be optimized by a suitable vehicle.
Chemically synthesized surface-active compounds are widely used in the pharmaceutical, cosmetic, petroleum and food industries. However, with the advantages of biodegradability, and production on renewable-resource substrates, biosurfactants may eventually replace their chemically synthesized counterparts. So far, the use of biosurfactants has been limited to a few specialized applications because biosurfactants have been economically uncompetitive. There is a need to gain a greater understanding of the physiology, genetics and biochemistry of biosurfactant-producing strains, and to improve process technology to reduce production costs.
This paper reports the results of experiments done to examine the explosibility of the waste products (fly ash and bottom ash) from pulverized fuels (coal and petroleum coke). Tests were conducted for the fly and bottom ashes alone and also for selected fly ashes blended with the fuels. The explosion parameters of interest were explosion pressure and rate of pressure rise. The fly ashes showed no propensity to explode, whereas one of the bottom ashes did show limited explosibility. Both findings can be explained with reference to the volatile matter content of the ashes. Admixture of either coal or petroleum coke with fly ash resulted in explosible mixtures at volatile contents in the range of 7-13%, with the value being dependent on the composition of the mixture components and their particle sizes.
Two ladybeetles, Cycloneda sanguinea and Harmonia axyridis, were exposed in the laboratory to eight fungicide formulations commonly used in citrus production in Florida. Both benomyl and the combination of copper and petroleum oil proved toxic to larvae of C. sanguinea that were exposed to concentrations corresponding to recommended field rates, either as leaf residues or in topical spray applications. Larvae of C. sanguinea also suffered significant mortality when exposed to neem oil as a leaf residue, but not after topical application. Larvae of H. axyridis exposed to these compounds completed development with the same success as control larvae in all trials. However, H. axyridis larvae exhibited slower development following exposure to leaf residues of ferbam applied at twice the recommended rate. Exposure to azoxystrobin as a leaf residue at twice the recommended concentration resulted in accelerated larval development in both species. No compounds appeared repellent to adult beetles of either species. Adult beetles of both species were observed resting on portions of filter paper treated with fosetyl-Al more often than on untreated, control portions. Azoxystrobin, ferbam and mefenoxam similarly arrested the movement of adult C. sanguinea, whereas benomyl and the copper and petroleum oil combination arrested the movement of adult H. axyridis. The differential sensitivity of the two coccinellid species is discussed in the context of the potential displacement of the indigenous C. sanguinea by the invasive H. axyridis.
Pseudomonas aeruginosa GS3 produced rhamnolipid biosurfactants during growth on carbohydrates, higher chain length n-alkanes and l-alkenes, petroleum crude oil and vegetable oils. With glucose as the substrate, maximum surfactant production (0.44 g/l) was observed during the stationary phase of growth. Partially purified rhamnolipids showed excellent surface-active properties in terms of reduction in the interfacial tension between them and a variety of hydrocarbons, hydrocarbon mixtures and vegetable oils and formation of stable emulsion.
Ethyl alcohol is one of the United States and world's major chemicals. Beverage alcohol in the United States must be prepared from cereal grains or other natural products. The U.S. industrial alcohol market has remained relatively stable for several years at approximately 300 million gallons annually. Most of this has been produced synthetically from petroleum raw material (gas and oil). These raw materials are experiencing major price increases and are in short supply. The production of ethyl alcohol from cereal grains and cellulosic raw materials by fermentation is technically feasible and has been proven. Alcohol produced from all such materials is equal to synthetic alcohol in quality and performance. Competitive economics have controlled the basic raw materials used. The major potential new ethyl alcohol market is as a component of automobile fuels. A 10% alcohol-gasoline blend in the United States would annually require over 10 billion gallons of anhydrous alcohol. Use of alcohol for this purpose is technically feasible. However, alcohol has not been economically competitive to date.
Hydrocarbons, stable organochlorines, metals and radionuclides are widespread in the freshwaters of the Canadian Arctic. Petroleum-associated hydrocarbon sources include natural seepage, wastes and effluents from exploration, production and refining at Norman Wells and spills. Hydrocarbons also originate from combustion of carbon-based fuels, generally at lower latitudes and then reach the Arctic with air movements. Organochlorine compounds also move throughout the hemisphere by aerial pathways and have become distributed widely in Arctic fish. The organochlorine at highest concentration in Arctic freshwater is alpha-HCH, while those generally at highest concentrations in the fish are toxaphene, PCBs and chlordane. Metals are ubiquitous in Arctic freshwaters, with inputs of several metals by precipitation superimposed on natural geologic backgrounds. Mercury is found in muscle of fish from Arctic freshwaters at concentrations up to about 0.5 ppm. Radionuclides are also widespread at levels below those acceptable in food, with some local elevations near former mines. The implications of these contaminants for the northern ecosystems and the people dependent upon them are still not clear. Preliminary studies of inducible enzymes in fish suggest that the thresholds for biological damage have not been reached.
A series of microbial associations capable of degrading various petroleum oils, emulsols, and crude oil were obtained by selection during periodic or continuous cultivation. The formation of these associations and oil-product degradation occurred most efficiently during aerobic flow cultivation. Under these conditions, oils were degraded by 92% on average. The microbial degradation of a petroleum oil depended on its brand, concentration, emulsification, and aeration.
The HPLC-SPE-NMR technique, supported by HPLC-MS measurements, was used to determine structures of major as well as some minor constituents of ethanol and petroleum ether extracts of Harpagophytum procumbens (Devil's claw) roots. This method was also shown to be applicable for rapid and precise on-line identification of secondary metabolites present in commercial herbal products of H. procumbens. A total of 15 compounds (1-14 and 17) were identified from the ethanol and petroleum ether extracts, including a novel Diels-Alder dimer 14. Optimization of the HPLC-SPE-NMR experiments included quantitative (1)H NMR measurements, determination of trapping and elution efficiency, effect of multiple trapping of analytes, use of various deuterated solvents for SPE cartridge elution, and effect of post-column dilution ratio of eluent with water. Linear accumulation of apolar and relatively polar analytes was demonstrated for at least 8-10 repeated trappings, resulting in greatly improved signal-to-noise ratios in NMR spectra and reduced acquisition times. Thus, the HPLC-SPE-NMR technique provides an efficient means of identification of multiple components of crude extracts. By allowing on-line generation of high-quality 2D NMR data without traditional purification of extract components, the HPLC-SPE-NMR methodology represents a paradigm shift in natural products research with respect to structure elucidation.
The protein and total amino acid contents of four mycelial fungal strains and one yeast were approximately the same for cultures harvested in the mid-log and early stationary growth phases. It was found that Fusarium oxysporum and Fusarium moniliforme contained approximately 30% more protein and total amino acids than Aspergillus niger. The amino acid composition of mycelial protein compares favorably with that of British Petroleum yeast protein Toprina produced commercially on hydrocarbon substrates. Fusarium spp. may be suitable for commercial production of microbial protein, especially when low-cost agricultural or industrial waste products are readily available as energy sources. Genetic manipulation of these fungi, such as induction of mutant strains through irradiation, may be desirable to obtain a mycelial product of improved yield and/or quality.
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A new bacterium that grows aerobically on cyclohexane was isolated from the wastewater plant of a petroleum refinery. This strain grows on a range of light hydrocarbons (C5-C10) as well as on some aromatic compounds such as toluene and m-cresol. Growth on hydrocarbons requires the presence of yeast extract and other complex media components that are not substrates for growth themselves. Strain CHX is resistant to cyclohexane and grows at concentrations up to 2 g l(-1). Strain CHX branches deeply within the Comamonadeae family of beta-proteobacteria and is tentatively assigned to the Brachymonas genus as Brachymonas petroleovorans CHX.
A method is described for the determination of deltamethrin, particularly in mild and dairy products. Residues and fat were co-extracted with acetone and light petroleum, partitioned with acetonitrile-methylene chloride and centrifuged (-10 degrees C). The extract was purified by gel permeation chromatography. A Florisil clean-up method was tested but did not seem effective enough. Analysis was performed by gas-liquid chromatography with a 63Ni electron-capture detector on 3% SE-30 using a short column (40 cm). Confirmation was effected by gas chromatography-mass spectrometry with an SE-30 capillary column (10 m). Recoveries from fortified samples ranged from 72 to 88% for milk spiked with 0.06 ppm and butter spiked with 2 ppm and was 94% for milk spiked with 0.016 ppm of deltamethrin.