The water solubility of crude oils and petroleum products
ABSTRACT Solubilities are reported for 42 crude oil and petroleum products in water as a function of temperature, salinity, oil weathering and water-to-oil volume ratio. The applicability of several analytical techniques (purge-and-trap gas chromatography, high pressure liquid chromatography, and fluorescence) for the determination of dissolved hydrocarbon concentrations is discussed critically. The effect of water-to-oil volume ratio on the apparent solubility of oils in water is discussed in detail.
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ABSTRACT: Chemical and toxicological characterization of unresolved complex mixtures in the water-soluble fraction of an artificially weathered Norwegian Sea crude oil was determined by a combination of chemical analysis and toxicity testing in fish in vitro bioassays. The water-soluble fraction of the crude oil was separated into 14 increasingly polar fractions by preparative high-pressure liquid chromatography. The in vitro toxicity (7-ethoxyresorufin O-deethylase activity, estrogenicity, and metabolic inhibition) of these fractions was characterized in a primary culture of liver cells (hepatocytes) from rainbow trout (Oncorhynchus mykiss). The main contributor to toxicity was one of the most polar fractions, accounting gravimetrically for more than 70% of the organic material in the water-soluble fraction and dominated by an unresolved complex mixture. Chemical analysis by gas chromatography-mass spectrometry and comprehensive two-dimensional gas chromatography-time of flight-mass spectrometry identified a large number of cyclic and aromatic sulfoxide compounds and low amounts of benzothiophenes (<0.1% of total mass) in this fraction. Commonly monitored toxic components of crude oil (e.g., naphthalenes, polycyclic aromatic hydrocarbons, and alkylated phenols) eluted in less polar fractions, characterized by somewhat lower toxicity. Normalization of in vitro responses to the mass in each fraction demonstrated a more even distribution of toxicity, indicating that toxicity in the individual fractions was related to the amount of material present. Although polar and nonpolar compounds contribute additively to crude oil toxicity, the water-soluble fraction was dominated by polar compounds because of their high aqueous solubility and the high oil-water loading. Under these conditions, the polar unresolved complex mixture-rich fraction might account for a large portion of crude oil toxicity because of its high abundance in the water-soluble fraction.Environmental Toxicology and Chemistry 06/2009; 28(9):1815-24. · 2.62 Impact Factor
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ABSTRACT: This article provides actual site data that confirm that turbid ground water samples collected from within the smear zone at petroleum release sites can be significantly biased high by the inclusion of a nondissolved component that is an artifact of the sampling process. Side-by-side comparisons show that reducing sample turbidity can result in significant reductions of reported concentrations for the ground water samples and that the lower turbidity results are more representative of the petroleum actually dissolved in the ground water. Depending on site-specific factors, ground water sample turbidity can be reduced by four field-based and two laboratory-based methods. These methods should be used routinely at sites where turbid samples with a nondissolved component are being collected.Ground Water Monitoring and Remediation 08/2009; 29(3):77 - 83. · 1.05 Impact Factor
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ABSTRACT: The evaporative weathering properties, chemical composition, and toxicity of three Australian Northwest Shelf crude oils and an Australian diesel fuel were evaluated. The crude oils include one each of a condensate, a light, and a medium crude oil. Between 23 and 100% of the mass of the oils is lost during evaporative weathering equivalent to about 1 week on the sea surface. During weathering, the oils lose most of their monocyclic aromatic hydrocarbons (MAHs) and phenols; concentrations increase of less volatile phenols and polycyclic aromatic hydrocarbons (PAHs). The acute toxicity of water-accommodated fractions (WAFs) of the fresh and weathered oils to six species of temperate and tropical marine animals ranges from > 100% to about 11% WAF. The MAHs are the most important contributors to the acute toxicity of the WAFs of the fresh oils. The contribution of PAHs to WAF toxicity increases with weathering. About 58% of the hazard indices (HI: exposure concentration/acutely toxic concentration) for the WAFs of the two light oils weathered for the equivalent of 1 d are attributable to PAHs. The toxicity of the WAFs of the condensate and light crude oil can be accounted for by MAHs, PAHs, and phenols; WAFs of the middle-weight crude oil and diesel fuel are higher than predicted based on their concentrations of total MAHs, PAHs, and phenols, indicating that other components of the WAFs are contributing to their toxicity. These components may include the unresolved complex mixture and polar compounds (resins).Environmental Toxicology and Chemistry 11/2009; 19(7):1809 - 1821. · 2.62 Impact Factor