The recent announcement in Victoria by federal Fisheries and Oceans Minister Jonathan Wilkinson promoting the Canadian government’s upgraded oil-spill-response capabilities was, for all intents and purposes, an attempt to soft-sell the Trans Mountain pipeline expansion to British Columbians.
Wilkinson’s public-relations exercise comes in the wake of the Federal Court of Appeal ruling quashing the approval for Trans Mountain, due largely to the failure to consider the pipeline expansion’s impacts to the marine environment and endangered southern resident killer whales, as argued in the lawsuit brought by Raincoast Conservation Foundation and co-plaintiffs.
Unfortunately, the government’s spill-response system still looks very much like conventional spill-response systems that have been in place in British Columbia and around the world since the 1970s, systems that include booms and skimmers, and consider 10 to 15 per cent oil recovery a success.
Not only is the bar for oil recovery extremely low, but past experience on the B.C. coast has shown that the rough conditions commonly encountered can render booms and skimmers not just ineffective, but unusable. In the likely event that booms and skimmers cannot be deployed at an offshore spill due to weather conditions, Trans Mountain indicated in its submission to the National Energy Board that it would consider the use of dispersants such as Corexit 9500. At the time, Corexit 9500 was not approved for use in Canada. However, in June 2016 the federal government quietly approved its use.
The intended purpose of dispersants is to break up oil slicks on the water’s surface by increasing the rate at which oil droplets form and move into the water column. Chemical dispersion does not reduce the amount of oil entering the marine environment; rather, it aims to change where it goes and how quickly it gets there.
The idea is to turn the oil into small droplets that are more easily degraded by naturally occurring microbes. However, Corexit has been found not only to be toxic to these microbes, but also to suppress their oil-degrading ability.
There are significant concerns about the use of Corexit on a spill of diluted bitumen. Corexit’s effectiveness in dispersing dilbit is unproven at best, and a growing body of research shows that Corexit is toxic to fish and wildlife, casting doubt on whether the supposed cure is any safer than the disease.
Both Trans Mountain and Environment Canada examined the efficacy of dispersants on dilbit. Trans Mountain found that Corexit 9500 was “marginally effective” on six-hour weathered dilbit and “not particularly effective” on more weathered dilbit. Environment Canada found that in breaking-wave conditions, dispersants were able to disperse less than half of the dilbit released into the water. In non-breaking waves, dilbit was not affected at all by dispersant application. The report concluded that the physical properties of dilbit “limit the effectiveness of currently available spill-treating agents.”
As noted, Corexit 9500 can also be toxic to wildlife. For some organisms, such as herring embryos, toxicity occurs because Corexit 9500 does what it was designed to do, increasing the concentration of petroleum hydrocarbons in the water column. However, recent research shows that not only is Corexit 9500 toxic, but a combination of Corexit and oil can be far more toxic than either product alone. In marine plankton, Corexit and oil together caused up to a 52-fold increase in toxicity.
This increased toxicity is due in part to the fact that dispersants can increase uptake (by fish and wildlife) of the toxic parts of oil. However, some of the toxicity of Corexit 9500 also appears to be due to components called surfactants, which can interfere with the ability of cells to metabolize petroleum hydrocarbons and can be more toxic than Corexit 9500 as a whole.
The combination of spilled dilbit and dispersants has the potential to negatively affect B.C.’s killer whale populations. For cetaceans, which must surface to breathe, the inhalation of evaporated toxic components of dilbit combined with airborne Corexit 9500 could pose a serious risk.
What stands out from this growing body of research is how poorly we understand the toxicity of dispersant combined with any type of oil. There are a vast number of potential toxicity scenarios, depending on the chemicals present, exposure routes, weather conditions and species, among many other variables.
Almost three decades ago, researchers warned about these complexities, stating that “rigorous toxicological comparison of untreated and dispersant-treated oil is complicated by the fact that when oil, sea water and dispersants are mixed, a complex multiphase system results. In this complex system, aquatic organisms can be exposed to many toxicants, in many forms, which can have several modes of action.”
Why, then, would the federal government even attempt to pursue the Corexit route? The answer might be largely a question of optics. Undispersed oil can eventually reach shorelines, coating birds and mammals while creating a public-relations nightmare for the government of Canada, the new owner and operator of the Trans Mountain pipeline and oil tanker project.
Kate Logan is an independent toxicologist whose work focuses on the impacts of oil pollution. Chris Genovali is executive director of Raincoast Conservation Foundation.
