Analyses of Water Samples From the Deepwater Horizon Oil Spill: Documentation of the Subsurface Plume
Document Type
Article
Publication Date
3-21-2013
Department
Marine Science
School
Ocean Science and Engineering
Abstract
Surface and subsurface water samples were collected in the vicinity of the Deepwater Horizon (DWH) wellhead in the Gulf of Mexico. Samples were extracted with dichloromethane and analyzed for a toxic component, polycyclic aromatic hydrocarbons (PAHs), using total scanning fluorescence (TSF) and by gas chromatography/mass spectrometry (GC/MS). An aliquot of fresh, floating oil from a surface sample was used as a DWH oil reference standard. Twelve of 19 samples collected from 24 May 2010 to 6 June 2010 on the R/V Walton Smith cruise contained TSF maximum intensities above background (0.7 μg L-1 based on 1 L sample size). These 12 samples had total petroleum hydrocarbon (TPH) concentrations as measured by quantitative gas chromatography flame ionization detector (FID) ranging from 2 to 442 μg L-1. Quantitative GC/MS analysis of these 12 samples resulted in total PAH concentrations ranging from 0.01 to 59 μg L-1. Low molecular weight, more water-soluble naphthalene and alkylated naphthalene dominated the PAH composition patterns for 11 of the 12 water samples. Sample 12 exhibited substantially reduced concentrations of naphthalenes relative to other PAH compounds. The total PAH concentrations were positively correlated (R2 = 0.80) with the TSF maximum intensity (MI). TSF is a simple, rapid technique providing an accurate prediction of the amount of PAH present in a sample. TSFderived estimates of the relative contribution of PAH present in the oil provided evidence that PAH represented ~10% of the higher molecular weight TPH. The subsurface oil plume was confirmed by the analyses of discrete water samples for TSF, TPH, and PAH.
Publication Title
Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record Breaking Enterprise
First Page
77
Last Page
82
Recommended Citation
Wade, T.,
Sweet, S.,
Sericano, J.,
Guinasso, N.,
Diercks, A.,
Highsmith, R.,
Asper, V.,
Joung, D.,
Shiller, A.,
Lohrenz, S.,
Joye, S.
(2013). Analyses of Water Samples From the Deepwater Horizon Oil Spill: Documentation of the Subsurface Plume. Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record Breaking Enterprise, 77-82.
Available at: https://aquila.usm.edu/fac_pubs/19006
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