The Testing, Assessment, and Use of Dispersants: A Systematic Approach

Abstract

Wardrop, J.A.,* AGC Woodward-Clyde; Smith, J.P.,* Maxus Southeast Sumatra; Palmer, Don, Marine Science Laboratories; Seignior, Michael, AGC Woodward-Clyde; Fucik, Ken, SeaCrest Laboratories; Giroletti, Mark, BHP Laboratories; and Leeder, John, Amdel Abstract Dispersants are a valuable tool in oil spill management but also one that causes considerable concern amongst environmental groups. Some of these concerns are based on observations dating back to the Torrey Canyon oil spill of 1967 and are consequently dismissed on the basis that the dispersant and the manner in which they are used have changed considerably since then. However, it must be stated that chemically dispersed oil is generally toxic, even if the dispersant themselves have a low toxicity. Consequently environmental damage may result from their use. The decision on whether to use dispersant or not depends then on the relative damage that can be expected from dispersed oil compared to undispersed oil. In order to evaluate this potential, it is necessary to determine the efficiency of dispersant on an oil and the influence of chemical dispersant on the behaviour and toxicity of oil, both at sea and on shorelines. The paper discusses a systematic approach to the testing of dispersant and oils in order to better predict and assess possible environmental and operational benefits. The use of the procedures in the testing of two paraffinic Indonesian crude oils is discussed. The broader scientific information currently available suggests a number of areas in which additional data is required. Introduction The use of chemical dispersant remains one of the most controversial aspects of spill control and this controversy is based largely upon concerns about dispersant toxicity and increased environmental damage from dispersed oil. Some of the public concerns hark back to the ‘Torrey Canyon’ oil spill (U.K., 1967). Following this spill large volumes of industrial degreasers and cleaning agents were used on oiled shorelines. Not surprisingly, the use of these products, together with harsh cleaning methods such as scouring, resulted in a lot of damage to shoreline communities. However, these products were not dispersant and had toxicities far greater than the dispersant that were produced in the following years. In the following decades formulations continued to be refined and both efficiency and toxicity have been improved. Recent reviews have assessed decades of research and agree that, carefully used, dispersant are a valid spill control option. P. 291^