DO BASINS AND BEAKERS NEGATIVELY BIAS DISPERSANT-EFFECTIVENESS TESTS?

ABSTRACT Beaker and basin dispersant-effectiveness tests are used to help determine if application of dispersants in a real oil-spill incident is worthwhile. This paper provides evidence indicating that these tests negatively bias expected dispersion at sea because beakers and basins do not allow the spreading of oil slicks that occurs after application of dispersant in the unbounded open ocean. One reason is that closed system walls and/or oil-slick containment methods impose physical boundaries that restrict oil spreading. In addition to these physical constraints, surfactant films developed after applying dispersant form on the water surface surrounding an oil slick and act as chemical herders to keep slicks thick. This occurs in the field during a real incident and in beaker and basin dispersant-effectiveness tests. Surfactant films on the water surface, however, are fragile and can't persist in the open ocean but can persist throughout the short duration of standard dispersant-effectiveness tests. Th...