The U.S. Environmental Protection Agency (EPA) is developing a protocol for testing the effectiveness of surface washing agents (SWAs) in a laboratory setting. The criteria for evaluating SWA effectiveness is based on the amount of crude oil that can be removed from a substrate with a specified amount of test cleaner. For protocol development and testing, acid washed sand was used as the shoreline substrate. Prudhoe Bay Crude, a medium weight EPA/American Petroleum Institute (API) standard reference oil, and three SWAs were tested. Oil was applied to the sand in 2″ x2″ x2″ stainless steel mesh baskets and allowed to weather for a period of time before the SWA was applied. SWA was applied as a neat solution at a product to oil volume ratio of 2:1. The baskets were then submerged in seawater in 1-L beakers and agitated on a rotary shaker table. The effects of testing variables, including substrate hydration, mode of oil application, oil-weathering time, oil-SWA contact time, mixing speed, and mixing time were evaluated. The wash water and sand were extracted separately with DCM and the quantity of oil in the extracts was measured by UV-visible spectrophotometry. The efficiency of the SWA was determined based on the mass of oil released into the wash water relative to the total mass of oil applied.

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