Field and experimental tainting of arctic freshwater fish by crude and refined petroleum products

A crude oil spill and a diesel fuel spill in Arctic rivers both resulted in complaints from downstream populations that fish were tainted with an oily taste. Laboratory exposures of fish confirmed the ability of the spilled materials to produce taints in fish. These experiments led to a more systematic study of the relationship between exposure of fish to oil in the water and sensory responses of taste panels. Rainbow trout and arctic charr were exposed to three mixtures of Norman Wells crude oil in water over a 72 h period and then transferred to clean holding tanks for a further 600-840 h. Three fish were removed from each tank at intervals over both the uptake and clearance phases so that rates of production and clearance of the oily taste could be estimated. All panelists were able to discriminate between treated and untreated fish during the uptake and early clearance phases. Some continued to detect tainting in the fish even by the end of the clearance phase. The implication of these taste panel results is that oil tainting is sensitive to dosage of oil, duration of exposure, and duration of post-exposure time in clean water. Arctic charr can be expected to become tainted after an exposure of only a few hours, and to remain tainted for over a month following cessation of exposure. 7 refs., 4 figs