DISPERSANT EFFECTIVENESS TESTING ON CHEMICAL FLOATERS AND ITS ENVIRONMENTAL CONCERNS

摘要

With the growing interest and focus on Hazardous Noxious Substance (HNS) spill worldwide, Oil Spill Response & East Asia Response Ltd (OSRL/EARL) has embarked on an HNS spill response study. One important part of the study is to consider the appropriate type of response strategies for HNS spills. As this study focuses mainly on petrochemical floaters, two strategies are short listed, namely, containment and recovery, and dispersants application. This paper will discuss in depth the latter. Dispersants application during oil spills is common, but it has not been tested (nor practiced) to date on a Hazardous Noxious Substance (HNS) spill.rnDispersants, which are composed of solvents and surfactants, work by lowering the interfacial tension between oil and water. Theoretically, dispersants work on hydrocarbons that are poorly soluble in water. Dispersants application may also be the preferred strategy because it minimizes contact between responders and the spilled chemicals, thus minimizing the associated human exposure risks.rnWith this objective in mind, OSRL/EARL has collaborated with a test laboratory to conduct lab-scale experiments on effectiveness of dispersants on floating chemical slicks. This paper will be discussing the development of the experimental procedures and findings from these experiments.rnApart from the effectiveness of dispersants on chemical slicks, one major concern resulting from dispersing chemicals into the water column would be" the environmental and ecological effects of doing so. There will also be a brief discussion on the usage of common pollution indicators (such as aquatic toxicity, waterfowl toxicity, biochemical oxygen demand (BOD) and lethal concentration (LC_(50))) if dispersants are applied.