Residues of Bunker C Oil in Chedabucto Bay, Nova Scotia, 6 Years After the <i>Arrow</i> Spill

Abstract

The Arrow spill in February 1970 heavily oiled approximately one half of the 600 km shoreline of Chedabucto Bay, Nova Scotia. An extensive field survey and chemical analysis of sediment samples for aliphatic and polycyclic aromatic hydrocarbons identified only a few locations where Arrow Bunker C remained in the intertidal and sublittoral sediments. The upper intertidal zones of Rabbit, Crichton, and Durell islands remain covered with an oil and sediment mixture of a "pavement-like" consistency. Several areas showed visual and chemical evidence of recent spills during the survey period. All sublittoral sediment samples contained hydrocarbons of petroleum origin. The distribution of the most highly contaminated sublittoral sediments suggests either reentry of stranded oil into the water column and into the sublittoral sediments or contamination from shipping and fishing vessels. Concentrations in the sublittoral sediments are below those found toxic to benthic organisms. An estimation of the amount of Bunker C remaining in Chedabucto Bay is impossible due to the patchy distribution, contributions of more recent spills, and the absence of adequate control sites. Key words: Bunker C, oil spill, Chedabucto Bay, gas–liquid chromatography, fluorescence spectroscopy, n-alkanes, polycyclic aromatic hydrocarbons