Oil Spills in Polar Climates: The Bahia Paraiso Accident

ABSTRACT Spillage of -600,000 liters of refined product (diesel fuel arctic, DFA) into Arthur Harbor in January 1989 by the Bahia Paraiso marked the beginning of one of the first major spill clean-up and monitoring efforts in Antarctica. The impacted area contains numerous islands, breeding sites for sea birds and penguins, seal habitats, as well as abundant assemblages of macroalgae and invertebrates. Intertidal areas were most directly impacted and all components of the harbor ecosystem were contaminated during the first few weeks of the spill. DFA was detected in tissues from birds, limpets, macroalgae, clams, bottom feeding fish as well as in water and sediments. While the most intense contamination was during the first few weeks, some areas continued to be contaminated one year after the incident. The high energy environment, the relatively small volume of material released, and the volatility of the refined product combined to limit the spill's impact both areally and temporally. Even in this polar climate most of the spilled material evaporated. The remaining material was diluted with seawater and swept from the area by winds and currents. INTROPUCTION Man's activities in the southern oceans have raised concerns about human impacts on what is seen as one of the last pristine areas on earth. Potential mineral exploration and increasing tourism subjects even the remotest areas to possible petroleum contamination. While the impact studied in temperate climates these findings may not be directly applicable to high latitude, cold environments. The grounding of the Bahia Paraiso in Arthur Harbor, Antarctica provided one of our first experiences in responding to, and monitoring of, an oil spill in Antarctica. Enroute to resupply an Argentine Antarctic base the Bahia Paraiso ran aground on 28 January 19891,2. The vessel contained a cargo of diesel fuel arctic (DFA), jet fuel (JP-1), gasoline and compressed gas cylinders totaling more than one million liters. An estimated 600,000 liters of DFA were released during the main phase of the spill. A comprehensive sampling effort implemented within one day of the spill included collection of water, intertidal organisms, sediment from beaches, and oil slicks. The analysis of these samples provides information on the location, fate, and effects of the spill. The hydrocarbon chemistry portion of the program, which focused on documenting the distribution and fate of the petroleum release, is reported here. METHODS A variety of samples were collected for use in this study (Figure 1). Samples from the intertidal and subtidal (sediments, macroalgae and limpets) were collected by divers or from the shore. Sediments were collected in syringes and stoppered by the diver or scooped up with clean spatulas into sample containers. Sediment samples in deeper portions of the bays were sampled using a Smith-MacIntyre grab sampler from the R/V Polar Duke. Water column samples were diver collected by opening combusted glass stoppered bottles immersed to the appropriate depth in the water column or by 30 L Go-Flo Niskin bottles from the R/V Polar Duke. Slicks were collected by skimming the water surface into a glass bottle or by a screen mesh. Refined products were collected from the Bahia Paraiso, R/V Polar Duke, Palmer Station and Old Palmer Station including JP-1, DFA, lube oil, heating fuel and hydraulic fluid.