Dispersed and Particulate Petroleum Residues in the Gulf of St. Lawrence

Abstract

Concentrations of petroleum residues both as material in solution or dispersed through the water column and as fresh oil or tarry particles floating on the surface in the Gulf of St. Lawrence were measured during July–August 1971. Dissolved and dispersed forms were present in concentrations generally less than 5 μg/liter over the southern and western regions while 5–10 μg/liter were encountered in the north and east. A major source of these residues appears to be the Atlantic water that enters through Cabot Strait, and the distribution of these materials is closely related to the circulation of water within the Gulf. Surface oil was present at approximately 50% of the stations occupied in concentrations generally less than 100 μg/m2 but as great as 12,400 μg/m2 in the vicinity of the sunken barge Whale. There is no evidence to indicate an appreciable change in concentrations to those of a year ago.