Chemical and Toxicological Characterisation of Water Accommodated Fractions Relevant for Oil Spill Situations

Hokstad, Jorunn N.; Faksness, Liv-Guri; Daling, Per S.; Buffagni, Melania

doi:10.2118/61468-ms

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…With DOSS being an anionic surfactant, a possible repulsion between the polar head group while adsorbing at the oil–water interface may have accounted for the reduction in the dispersion effectiveness. Studies have shown that DOSS easily desorbs into salt water after emulsion formation, and this desorption results in the coalescence of smaller emulsion droplets into larger ones. Visual observations made during the baffled flask test attest to this fact because there was oiling-out and creaming of the emulsions formed with solubilized DOSS.…”

Section: Resultsmentioning

confidence: 99%

“…The formation of larger emulsion droplets increases their rising velocity and as a result, these oil droplets fell out of the sampling zone during the analysis done with the baffled flask test. The oxyethylene “hairs” in Tween 80 are important for providing steric stabilization to the oil droplets and preventing their coalescence . The rate of desorption of Tween 80 from the oil–water interface has therefore been reported to be much slower than that of DOSS, and this is responsible for the much higher dispersion effectiveness recorded for Tween 80 at higher SOR.…”

Section: Resultsmentioning

confidence: 99%

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Soybean Lecithin as a Dispersant for Crude Oil Spills

Nyankson

DeCuir

Gupta

2015

ACS Sustainable Chem. Eng.

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The toxicity of oil spill dispersants to marine organisms has necessitated the search for alternative dispersant formulations that are environmentally benign. Soybean lecithin, a well-known surface active agent in the food industry, is effective at stabilizing oil-in-water emulsions. In addition to its excellent emulsification properties, it is biodegradable, less toxic than the traditional chemical dispersants, and ecologically acceptable. In this study, soybean lecithin was used to formulate dispersants for crude oil spill application. Soybean lecithin was fractionated into phosphatidylinositol (PI) and phosphatidylcholine (PC) enriched fractions using ethanol. The fractionated PI was deoiled and characterized with Fourier transform infrared spectroscopy (FT-IR). The crude soybean lecithin (CL) and the fractionated PI and PC were solubilized in water and their dispersion effectiveness determined using the U.S. EPA's baffled flask test. The dispersion effectiveness of these solubilized dispersants was compared with that of solid crude lecithin (SL). The dispersion effectiveness of PC was found to be higher than those of SL, CL, and PI at all the surfactant-to-oil ratios (SORs) tested. However, when the fractionated PI was modified or "functionalized" (FPI) with additional hydroxyl groups to alter the hydrophilic−lipophilic balance (HLB), its dispersion effectiveness improved remarkably and was higher than that of PC. At higher SORs (>28 mg/g), the dispersion effectiveness of FPI was slightly higher than that of solubilized DOSS and Tween 80 in propylene glycol. The dispersion effectiveness of PC and FPI on Texas (TC) and light crude (LC) oil samples were almost the same. PC and FPI performed better at the higher salinity of 3.5 wt % than the lower salinities of 0.8 and 1.5 wt %. The findings from this study suggest that dispersants formulated from fractionated PI and PC have the potential to replace traditional dispersant formulations.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Soybean Lecithin as a Dispersant for Crude Oil Spills

Nyankson

DeCuir

Gupta

2015

ACS Sustainable Chem. Eng.

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“…Because dispersants often are a key oil spill response option, dispersant may be added to the test oil during WAF preparation at a volume ratio that reflects the dosage applied in field response (e.g., 1:20 dispersant to oil). The test procedure used to prepare chemically dispersed oil (chemically enhanced WAF [CEWAF])—including the oil loading selected, amount of mixing energy, mixing and settling times, and use of chemical dispersant—can greatly affect the composition of the WAFs, including the amount of oil that is entrained in the test media as oil droplets . Often, this complicates comparison of toxicity results for oils among studies with different experimental designs.…”

Section: Introductionmentioning

confidence: 99%

Evaluating toxicity of heavy fuel oil fractions using complementary modeling and biomimetic extraction methods

Redman

Parkerton

Letinski

et al. 2014

Enviro Toxic and Chemistry

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The toxicity of chemically dispersed heavy fuel oil (HFO) and 3 distillate fractions to rainbow trout (Oncorhynchus mykiss) embryos was evaluated using the PETROTOX model and a biomimetic extraction technique that involved passive sampling of oil-contaminated test media with solid-phase microextraction (SPME) fibers. Test solutions for toxicity testing were generated using a combination of dispersant and high-energy mixing. The resulting water accommodated fractions (WAF) provided complex exposure regimens that included both dissolved hydrocarbons and oil droplets. The toxicity of the various fractions differed by approximately 3 orders of magnitude when expressed on the basis of WAF dilution. Using detailed compositional data, the PETROTOX model predicted the speciation of hydrocarbons between dissolved and oil droplet phases and explained observed toxicity based on computed dissolved phase toxic units (TUs). A key finding from model calculations was that dissolved hydrocarbon exposures and associated TUs were a nonlinear function of WAF dilution, because dissolved hydrocarbons were largely controlled by the dissolution of oil droplets that were transferred in WAF dilutions. Hence, oil droplets served to "buffer" dissolved concentrations in WAF dilutions at loadings greater than 1 mg/L, resulting in higher dissolved concentrations and TUs than expected based on dilution. The TUs computed at each WAF dilution explained the observed toxicity among the HFO and fractions to within a factor of 3. Dissolved material measured by SPME showed a consistent relationship with model-predicted TUs, confirming the utility of this approach for providing an integrated measure of exposure to bioavailable hydrocarbons. These 2 approaches provide complementary tools for better defining bioavailability of complex petroleum substance.

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“…A concentration of a chemical in water resulting in a 50% decrease in the bioluminescence of the target bacterium at a certain time (5-15 min) is used as an indicator for the toxicity assessment (King et al, 2014). EC 50 values of oil WSF ranged from 1.08 to 17.18 mg/L, depending on the composition of oils (Hokstad et al, 2000;Rhoton et al, 2001;Fuller et al, 2004;Reá tegui-Zirena et al, 2014). Normally, aromatics in WSF have a much higher toxicity than saturates.…”

Section: Bacteriummentioning

confidence: 99%

Ecotoxicity Studies for On-Site Disposal of Decant Water During Oil Spills: A Review

Liu

Chen

Ling

et al. 2022

Front. Environ. Sci.

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Mechanical oil recovery, a most used tool for oil spill response, can generate a considerable proportion of oil-contaminated water (10–70%). Large storage space is commonly required to transport the recovered oil and water mixture to shore. Transit and transportation consume loads of time, money, and resources while reducing oil recovery’s overall efficiency and capacity. Techniques of on-site treatment and disposal of oily wastewater provide benefits for oil recovery by freeing storage space. However, the high petroleum content of decant water can lead to uncertain risks, if discharged into the marine ecosystem. Insufficient ecological toxicity data and research limit the standardization and establishment of regulative tools. To fill the knowledge gaps, this review comprehensively summarized recent studies on the potential impacts of the organic composition in decant water, including oil–water accommodated fractions, dispersed oil droplets, and other related chemicals, on various marine species (i.e., bacterium, invertebrates, fishes, plants, reptiles, and mammals). The toxicity effects and the ecological endpoints of oils, TPH, and PAHs on different species were discussed. Recommendations for future ecological impacts and decant water composition were provided to support the on-site disposal of the water fraction.

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Chemical and Toxicological Characterisation of Water Accommodated Fractions Relevant for Oil Spill Situations

Cited by 8 publications

References 3 publications

Soybean Lecithin as a Dispersant for Crude Oil Spills

Soybean Lecithin as a Dispersant for Crude Oil Spills

Evaluating toxicity of heavy fuel oil fractions using complementary modeling and biomimetic extraction methods

Ecotoxicity Studies for On-Site Disposal of Decant Water During Oil Spills: A Review

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