The Fate of Oil in the Water Column Following Experimental Oil Spills in the Arctic Marine Nearshore

Abstract

Petroleum hydrocarbon concentrations in the water column were monitored after a release of crude oil onto the water surface and subsurface release of chemically dispersed oil. During the surface release, petroleum hydrocarbons did not disperse into the water column deeper than m. The highest concentrations observed under the slick were less than 2 m g P . The chemically dispersed oil release resulted in concentrations over 5 mg.f' i n the Bay 9 study area for 12 hours, and petroleum hydrocarbons were detectable by in siru fluorometry for more than 4 days. The dispersed oil di not undergo further weathering for 24 hours. Estimated exposures of the benthic communities to oil in the three experimental bays were 3 mgd-'.h, 3 mg.f'.h, and 300 mg#'.h respectively. The highest exposures were to oil retaining many of its more toxic components. &SUM& La concentration d'hydrocarbures pitroliers a t t t mesur6e dans la colonne d'eau apds un dtversement de p6trole brut en surface, et u dtversement de pitrole disperse chimiquement sous la surface. Lors du dtversement en surface, les hydrocarbures pitroliers ne se sont pas disperses dm la colonne d'eau B plus d' 1 m de profondeur. Les plus hautes concentrations observtes sous la nappe ne dtpassaient pas 2 mg.1". Le dtversement d pitrole disperst chimiquement a provoqut des concentrations dtpassant 50 m g P pendant 12 heures dans la baie expirimentale no 9, et les hydrocarbure pitroliers ont pu & t r e dttectts par fluoromttrie in siru pendant plus de 4 jours. Le pitrole disperse n'a pas subi de degradation suppltmentaire pendant 2 heures. On a estimt l'exposition au pitrole des communauth benthiques des trois baies expirimentales B 3 mg.l".h, 30 mgd".h et 300 m g P .