Modelling the Effects of Chemical Dispersant on the Fate of Spilled Oil

Haibo Niu, Rujun Yang, Yongsheng Wu, Kenneth Lee

The proposed Energy East pipeline project has raised concerns about potential oil spills in Saint John, New Brunswick, due to increased tanker traffic. While environmental conditions such as strong tide and current could pose challenges for using mechanical recovery methods if a spill occurs in the area, chemical dispersant could be an alternative oil spill countermeasure. However, the application of chemical dispersant in shallow water and costal zones remains an issue of debate. To study if chemical dispersant could be effective for potential oil spills in Saint John, a 3-dimensional model was used to simulate the transport of oil following a hypothetical release of 1000 m3 Arabian Light crude under winter conditions. A stochastic approach was used to take into account the uncertainties of environmental inputs. The results show a significant reduction of oil ashore, and enhanced biodegradation with dispersant application, but these effects were accompanied by an increase of oil in sediment and water column, which is a concern. While the results are only conclusive for the selected scenarios of winter release, the method could be extended to other months and seasons of the year to support more detailed net environmental benefit analysis regarding dispersant application.