Characterization of the Particulate Emissions from the BP Deepwater Horizon Surface Oil Burns
Citation:
Gullett, B., M. Hays, D. Tabor, AND R. Vander Wal. Characterization of the Particulate Emissions from the BP Deepwater Horizon Surface Oil Burns. MARINE POLLUTION BULLETIN. Elsevier Science Ltd, New York, NY, 107(1):216-223, (2016).
Impact/Purpose:
This work presents an analysis of smoke particles opportunistically caught during the in situ surface oil burns during the 2010 BP Deepwater Horizon diasaster. While there are no standard methods established for sample collection under these conditions, this fortuitous and opportunistic sample allows us the rare chance to propose a baseline level of pollutants emitted from in situ oil burning. This sample is unique for the BP disaster and no other samples have ever been taken and analyzed from real at sea burns. As such, this sample presented an important opportunity for the EPA to establish even a minimum knowledge base on emissions from these oil spill treatments. While this is the case, the results from this analysis do not imply strong metal or dioxin emissions; PAH concentrations appear to be an order of magnitude less than land-based simulations.
Description:
Opportunistic particle samples were gathered from the sail of a tethered aerostat during at-sea plume sampling of the purposely-burned surface oil during the BP Deepwater Horizon disaster in the Gulf of Mexico. Particles were analyzed for polycyclic aromatic hydrocarbons (PAHs), organic carbon (OC), elemental carbon (EC), metals, and polychlorinated dibenzodioxins/dibenzofurans (PCDDs/PCDFs). Emission factors were calculated using previous sampling values of background-adjusted CO2 and particulate matter (PM)-bound C. The mean of five thermal-optical analyses indicated that the burned crude oil particulate matter was 93% carbon (w/w) with the predominance being refractory elemental carbon (82% w/w) on average. PAHs accounted for roughly 60 ug/g of the PM mass or 4.5 mg/kg oil burned, at least an order of magnitude less than earlier laboratory based studies. Microscopy indicates that the soot from the in situ oil burns is distinct from more common soot by its aggregate size, primary particle size, and nanostructure within the primary particles. The PCDD/PCDF concentration of the PM was 1.5 to 3.3 ng toxic equivalency (TEQ)/kg PM sampled, about 10-fold lower than from a previous dedicated gas/solid sample, indicating loss of small particle-bound and more volatile PCDD/PCDF congeners through the aerostat sail.
