An evaluation of the methodology used for shipboard monitoring of oil spills

Scientific monitoring of oil spills is required to provide information for the effective planning of countermeasures. In the past, lack of integration of the monitoring effort has made the correlation and interpretation of data difficult. We reviewed (through interviews and questionnaires) the methodology of shipboard monitoring of oil spills to help in an evaluation of whether a fully integrated oil monitoring system is necessary and feasible. Most scientists required 2–3 days to mobilize their equipment for monitoring accidental oil spills. A major problem was acquisition of an appropriate vessel. Little experience with monitoring of hydrocarbons in air was described. There were very diverse approaches to slick observation and sampling. Slick sampling was ineffective in many cases. There was generally poor documentation of weather and sea state during accidental spills and therefore difficulty in the interpretation of oil observations. Fewer than half of the respondents had used in situ methodsfor monitoring oil in the water column. Most relied on discrete sampling, with subsequent analysis ashore. In situ methods are now more popular, but require more rigorous quality control programs than those used during past spill responses. Although computerized sensor systems have been developed for water column monitoring, the data from these systems are not integrated in real time with observations on the location and thickness of the slick and other data on sea state. Depending on the objectives of oil spill monitoring, a fully integrated shipboard oil monitoring system may reduce or eliminate many of the problems currently experienced by scientists working on oil spills.