NATURAL CLEANING OF OILED COARSE SEDIMENT SHORELINES IN ARCTIC AND ATLANTIC CANADA

Two long-term data sets are described that document the natural cleani ng of oiled shorelines on an Arctic and a North Atlantic coast in Cana da. Tn both cases there has been a well documented reduction in the di stribution acid amount of remaining oil that can be explained readily where the shores are exposed to wave action. Added insight into the pr ocesses by which shorelines can clean themselves in low wave-energy en vironments and in the absence of coastal erosion has been offered only recently. This insight involves a process by which mineral fine parti culates interact with the oil in the presence of seawater to form posi tively buoyant, micron-sized aggregates. Laboratory observations of sa mples collected from these shorelines demonstrate that this process do es occur and, therefore, can be invoked to partially account for the n atural cleaning of oiled shorelines in the two cases considered here.