Development of a Rational Oil Spill Dispersant Effectiveness Protocol

Autor: Edith L. Holder, Karen M. Koran, Albert D. Venosa, George A. Sorial, Dennis W. King
Rok vydání: 2001
Předmět:
Zdroj: International Oil Spill Conference Proceedings. 2001:471-478
ISSN: 2169-3358
2169-3366
DOI: 10.7901/2169-3358-2001-1-471
Popis: Chemical dispersants are used in oil spill response operations to enhance the dispersion of oil slicks at sea as small oil droplets in the water column. To be considered for use, the dispersants must be listed in the National Contingency Plan (NCP) Product Schedule. Since 1994, dispersants were required to pass an effectiveness test known as the Swirling Flask Test (SFT), which is described in Appendix C of 40 CFR 300. Listing of a dispersant on the NCP Product Schedule is contingent on the dispersant being at least 45% effective in dispersing South Louisiana crude (SLC) and Prudhoe Bay crude (PBC) oils as measured and calculated by the test. Shortly after adopting the SFT, the U.S. Environmental Protection Agency (EPA) began to receive complaints that the test was too rigorous and few dispersants that were previously listed on the NCP Product Schedule could achieve the 45% effectiveness criterion. Additionally, the SFT has been found to give widely varying results in the hands of different testing laboratories. A redesign of the test flask, which is characterized as being baffled with a stopcock at the bottom for undisturbed sample collection, is considered to be necessary to accomplish reproducibility within operators and between operators. This paper presents the development of a revised procedure for dispersant effectiveness testing, called the Baffled Flask Test (BFT), and reports the reproducibility of the revised procedure by three independent operators. It also details the development of pass/fail selection criteria. Experimental results are presented comparing the repeatability of the SFT and BFT methods with three operators determining the effectiveness of 18 dispersants on SLC and PBC oils. Statistical analysis of the results indicated that the overall mean effectiveness of the SFT for all 18 dispersants was only 19.7% compared to 64.6% by the BFT and the coefficient of variation for the SFT was 21.9% versus only 7.8% for the BFT.
Databáze: OpenAIRE
Externí odkaz: