Abstract:

Data supporting the publication DOI: 10.1016/j.ecss.2014.03.022 http://www.sciencedirect.com/science/article/pii/S0272771414000705 Effectiveness of Corexit 9500A for dispersing Louisiana crude oil was evaluated in salt water solutions containing natural materials in relation to salinity and dispersant-to-oil ratio (DOR). Experimental results showed that both salinity and DOR had significant effects on dispersion of Louisiana crude oil in the presence of different natural materials. The natural materials added to the salt water solutions included sea sand (South Beach, Miami, Florida), red mangrove leaves (Rhizophora mangle), seaweed (Sargassum natans), and sea grass (Halodule wrightii). Dispersant effectiveness (amount of oil dispersed into the water) was reduced significantly with increasing salinity with the minimum effectiveness observed in the salinity range between 30 and 50 ppt in all aqueous samples containing natural materials.

Suggested Citation:

Berrin Tansel et al. 2014. Dispersion of Louisiana crude oil in salt water environment by Corexit 9500A in the presence of natural coastal materials.. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7V122RZ

Publications:

Tansel, B., Lee, M., Berbakov, J., Tansel, D. Z., & Koklonis, U. (2014). Dispersion of Louisiana crude oil in salt water environment by Corexit 9500A in the presence of natural coastal materials. Estuarine, Coastal and Shelf Science, 143, 58–64. doi:10.1016/j.ecss.2014.03.022

Purpose:

The purpose of this study was to investigate the possible interactions of the environmental factors on the effectiveness of Corexit 9500A (dispersant) on Louisiana crude oil in salt water environment. Both the dispersant efficiency (reduction in surface tension) and dispersant effectiveness (fraction dispersed) were evaluated in laboratory conditions in relation to dispersant-to-oil ratio (DOR), salinity, and type of natural materials present.

Data Parameters and Units:

* [Sea Sand, Sea Grass, Seaweed, Mangrove leaves] Effectiveness, Surface Tension, Dispersant Efficiency (%) * Overall Regression of Coastal Surfaces * ML + SS regression * Experimental Dispersant Efficiency DE (%) verses Projected Dispersant Efficiency DE (%)

Methods:

The natural materials studied included those that are commonly found in coastal areas in South Florida, USA. These included sea sand (South Beach, Miami, Florida), red mangrove leaves (Rhizophora mangle), seaweed (Sargassum natans), and sea grass (Halodule wrightii). The effect of dispersant dosage (i.e., DOR) on surface tension was determined for the DORs ranging from 1:5 to 1:25 (v/v). Surface tension measurements were conducted in duplicates by a surface tension apparatus (Fisher Scientific, Suwanne, Georgia, USA). The variation of the surface tension measurements was about ±2 dyn/cm in the DOR range 1:25 to 1:10. The variation in surface tension measurements for the DOR of 1:5 was about ±4 dyn/cm due to the interference from the oil layer present. The effectiveness of the dispersant was determined by calculating the proportion of oil dispersed into the aqueous phase in relation to the total amount of oil added to the sample expressed as percent dispersion effectiveness. The oil from the aqueous phase was extracted with dichloromethane (DCM) according to the liquid/liquid extraction procedure described in the swirling flask dispersant effectiveness test (U.S. Environmental Protection Agency, 2003). Oil concentrations in the DCM extracts were determined with UV/Visible spectrophotometer (Cary 300 UV–Vis Spectrophotometer, Agilent Technologies, Santa Clara, California, USA) by measuring the absorbance at wavelengths 340, 370 and 400 nm. Randomly selected 5 test conditions were duplicated for error analyses. The error in the estimated dispersion effectiveness based on the extraction procedure was about ±2%.

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