The objectives of this study were to assess the field effectiveness and biological effects of low-pressure saltwater flushing of a thin (<4 mm) oil layer applied to a very fine intertidal sand. On average approximately 85 percent of the applied medium fuel oil mousse was found to be recoverable. Hydrocarbon analyses indicated negligible oil incorporation into flushed plots. The technique is believed to have been effective partly because the water table was successfully raised (by up to 20 cm), and also because the surface 3 to 4 cm was sufficiently disturbed to liberate oil that had penetrated the surface layer during the 2 hours between oil application and flushing. Counts of Arenicola marina casts in “oiled” plots were significantly lower (P = 0.02) than in the “oiled and then flushed” plots. The technique is likely to work with viscous oils deposited in 10 mm thick Strandlines on accessible sloping shores, where the sediment is greater than 4 cm thick and reasonably firm. The technique is likely to be unsuccessful on very coarse sands and gravels, fluid muds, and low shear strength sands, because of erosion and mixing of sediments and oil.

This content is only available as a PDF.