Abstract:

This dataset reports the results of experiments to assess the effect of photochemical weathering on dispersant effectiveness. Macondo well oil was artificially weathered in the lab for use in dark-control and light-exposed treatments. Light-exposed treatments were exposed in a solar simulator for up to 24 hours. This dataset reports natural and chemical dispersion, carbonyl stretching intensity, dispersant efficacy, density, dynamic viscosity, and adhesion. This dataset supports the publication: Ward, C.P., Armstrong, C.J., Conmy, R.N., French-McCay, D.P., & Reddy, C.M. (2018). Photochemical Oxidation of Oil Reduced the Effectiveness of Aerial Dispersants Applied in Response to the Deepwater Horizon Spill. Environmental Science & Technology Letters, 5: 226-231. doi: 10.1021/acs.estlett.8b00084

Suggested Citation:

Collin Ward, cward@whoi.edu. 2018. Dataset for: Photochemical Oxidation of Oil Reduced the Effectiveness of Aerial Dispersants Applied in Response to the Deepwater Horizon Spill. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7D50KHM

Publications:

Ward, C. P., Armstrong, C. J., Conmy, R. N., French-McCay, D. P., & Reddy, C. M. (2018). Photochemical Oxidation of Oil Reduced the Effectiveness of Aerial Dispersants Applied in Response to the Deepwater Horizon Spill. Environmental Science & Technology Letters. doi:10.1021/acs.estlett.8b00084

Purpose:

To assess the effect of photochemical weathering on dispersant effectiveness; compare the effect of photochemical to evaporative weathering on dispersant effectiveness; and to characterize the effect of photochemical weathering on the effectiveness of aerial dispersants applied in response to the Deepwater Horizon (DWH) oil spill.

Data Parameters and Units:

Time (hours), Chemical dispersion (%), Natural dispersion (%), Carbonyl content (%), Evaporative mass loss (0-30%), Exposure (light-24 hrs or dark), Dispersion (natural or chemical), Dispersant effectiveness (%), Density (g/mL), Viscocity (cP), Adhesion (mg mm^2), Solvent, Solubility (%)

Methods:

Macondo well oil was artificially weathered in lab in the dark to evaporative mass loss of 8, 15, 20 or 30%. Samples were placed in a solar simulator for up to 24 hours. Dark controls were used. After the incubation the light-exposed and dark-control were recovered and viscosity, density, adhesion and oxygen content were quantified. Viscosity was measured with a microVISC viscometer. Density was measured using a gastight syringe and an analytical balance was used to measure 50uL of sample. Adhesion was measured by submerging a clean stainless steel rod of known weight into 200 uL for 30 seconds, allowing to rest for 30 minutes in a draft shield, and reweighing the rod. FTIR was used to measure carbonyl stretching. The EPA recommended Baffled Flask Test was used to measure dispersant effectiveness. COREXIT EC9500A was used to chemically disperse light and dark treatment at a ratio of 1:20 dispersant:oil. Natural dispersion treatments were the fraction of oil that dispersed without the addition of a dispersant. Photo-oxidized Macondo well oil residues were mixed with dicholormethane, food-grade kerosene, dimethyl sulfoxides, methanol and acetone and solubility was measured.

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