Diluted bitumen, also known as dilbit, a mixture of oil sands bitumen and natural gas dilutants can seriously harm fish populations, according to research study at Queen’s University and the Royal Military College of Canada published this week.
At toxic concentrations, effects of dilbit on exposed fish included deformities and clear signs of genetic and physiological stress at hatch, plus abnormal or uninflated swim bladders, an internal gas-filled organ that allows fish to control their buoyancy. Exposure to dilbit reduces their rate of survival by impairing their ability to feed and to avoid predators.
Among the other findings from the study were
Embryo toxicity of dilbit was comparable to that of conventional oils.
Developmental malformations increased with increasing dilbit concentrations.
Chemical dispersion broadened the genotoxic effects of dilbit
“This new study provides a clearer perspective on the potential risks to Canada’s aquatic resources of dilbit spills, and a technical basis for decisions on dilbit transportation within Canada,” says Peter Hodson Environment Studies, Biology at Queens. “It reduces some of the uncertainty and unknowns about the hazards of dilbit.”
This study characterized the toxicity and physiological effects of unweathered diluted bitumen (Access Western Blend dilbit; AWB) to a fish used for laboratory studies. Embryos of Japanese medaka (Oryzias latipes) were exposed for 17 days to dilutions of dilbit physically-dispersed by water and chemically-dispersed by dispersants
AWB dilbit exposure was not lethal to medaka, but resulted in a high prevalence of blue sac disease (BSD), impaired development, and abnormal or un-inflated swim bladders. Blue sac is a disease of young trout and other salmonid species; usually caused by unsuitable hatchery water. It turns the yolk sac bluish and is thought to be caused by a lack of oxygen.
The research was funded by Fisheries and Oceans Canada’s National Contaminants Advisory Group and the next stage will determine whether fish species native to Canada will be affected by dilbit exposure. The work also includes the development of genetic markers of exposure to dilbit and toxicity that could be used to assess whether wild fish that survive a spill are still affected.
The research team includes Dr. Valérie Langlois (Environmental Studies, Royal Military College of Canada) and Dr. Barry Madison (Royal Military College of Canada).
Dr. Hodson is also a member of a Queen’s research team tasked to determine whether dilbit spilled into rivers would contaminate bed sediments, specifically areas where fish such as salmon, trout, chars, whitefish and graylings spawn, to the extent that the survival of their embryos would be affected.
The research was published in ScienceDirect and is one of the first studies of dilbit on young fish.
The finding could be significant because both the proposed Northern Gateway pipeline and the proposed Kinder Morgan expansion will cross areas near spawning streams.
A group of biologists from across Canada have proposed a nine step program to sustain healthy waterways and fisheries not only in this country but around the world.
The key to clean waterways and sustainable fisheries is for the management plan to follow nine guiding principles of ecological water management, according to John Richardson, a professor in the Dept. of Forest and Conservation Sciences at the University of British Columbia, one of 15 freshwater biologists who created the framework to help protect fish and ecosystems into the future.
Fish habitats need waterways that are rich in food with places to hide from predators and lay eggs, according to the framework published on January 31 in the journal Environmental Reviews.
“Fish are strongly impacted when nutrients, sediments or pollutants are added to their habitat. We cannot protect fish without maintaining a healthy freshwater ecosystem,” Richardson,who led the policy section on protecting fish habitats, said in a UBC news release. Other policy sections addressed areas such as climate change and biodiversity.
Humans have put key waterways at risk because of land development and the loss of the vegetation along rivers and streams, Richardson said, adding connecting waterways are also critical for healthy ecosystems. “If fish can’t get to breeding or rearing areas because of dams, culverts, water intakes or other changes to their habitats, then the population will not survive,” he said.
With more pressure on Canada’s waterways, Richardson and his colleagues wanted to create a framework of evidence-based principles that managers, policy makers and others could easily use in their work. “It’s a made in Canada solution, but the principles could be applied anywhere in the world,” he said.
The paper says:
Freshwater ecosystems are among the most imperiled on Earth with extinction rates of freshwater fauna higher than for many other ecosystems and vastly exceeding historic background rates/ Freshwater is vital to humans, and clean water is rapidly becoming a limiting resource for many societies. The greatest threat to freshwater ecosystems is the loss or alteration of freshwater habitats through human development yet our societies and economy depend directly on the services provided by healthy freshwater ecosystems.
It also notes:
Most ecosystem services of fishes are supported by a diverse fauna, not by merely the few species directly favoured by humans. Humans live side-by-side with fishes and other aquatic organisms in watersheds, and we derive our quality of life from the health of these ecosystems.
The paper, which was supported in part by federal government financing, only touches on the controversy over the gutting of the environmental protection for Canadian waterways by the Harper government. It goes on to stay that the protests are not enough and more is needed:
Recent changes to Canadian fisheries policies have motivated responses by the public and the scientific community yet a broad contemporary scientific assessment of what is required to manage freshwater fisheries resources is lacking. A template of the core ecological concepts underlying sound fisheries policies, based on the best available science will support policy and management decisions and the design of monitoring programs to evaluate the success of these actions.
With more pressure on Canada’s freshwater ecosystems, Richardson and his colleagues wanted to create a framework of evidence-based principles that managers, policy makers and others could easily use in their work. “It’s a made in Canada solution, but the principles could be applied anywhere in the world,” he says.
Healthy freshwater ecosystems are shrinking and reports suggest that the animals that depend on them are becoming endangered or extinct at higher rates than marine or terrestrial species, says Richardson. Humans also depend on these ecosystems for basic resources like clean drinking water and food as well as economic activity from the natural resource sector, tourism and more.
The components of a successful management plan include:
Protect and restore habitats for fisheries
Protect biodiversity as it enhances resilience and productivity
Identify threats to ecosystem productivity
Identify all contributions made by aquatic ecosystems
Implement ecosystem based-management of natural resources while acknowledging the impact of humans
Adopt a precautionary approach to management as we face uncertainty
Embrace adaptive management – environments continue to change so research needs to be ongoing for scientific evidence-based decision making
Define metrics that will indicate whether management plans are successful or failing
Engage and consult with stakeholders
Ensure that decision-makers have the capacity, legislation and authority to implement policies and management plans.
These recommendations are based on nine principles of ecology:
Acknowledge the physical and chemical limits of an ecosystem
Population dynamics are at work and there needs to be a minimum number of fish for the population to survive
Habitat quantity and quality are needed for fish productivity
Connecting habitats is essential for movement of fish and their resources
The success of freshwater species is influenced by the watershed
Biodiversity enhances ecosystem resilience and productivity
Global climate change affects local populations of fish
Human impacts to the habitat affect future generations of fish
The Genivar report for Transport Canada on oil spills say that some persistent effects can last for more than 40 years, based on a study of a spill in Cape Cod, Massachusetts. The report notes that persistent sub-surface oil is still a problem at Prince William Sound, site of the Exxon Valdez disaster in 1989.
On long-term effects, Genivar reports: “The ingestion of contaminated food (such as oiled mussels), may represent the most important exposure pathway for aquatic fauna during a chronic
phase. Chronic exposure to contaminated sediments is also important for fauna or
It goes on to stay that “large-scale oil spills might have considerable long-term
consequences on social structure and public health, interfering with traditions and
causing cultural disruptions.”
It appears that in the case of an oil-spill, time may heal some wounds, but not all of them, at least if time is considered within human lifetimes and the lifetimes of other species.
Ecological recovery is measured by how quickly individuals and populations of
species return to pre-spill conditions. It is determined by factors such as oil type,
exposure duration, water temperature, degree of weathering, spill response and the
individual and species-specific life history traits. In most environmental habitats,
recovery is completed within 2-10 years after a spill event, but in some exceptional
cases, such as in salt marshes, effects may be measurable for decades after the
In the case of the Exxon Valdez oil spill in Prince William Sound… in 1989, the persistence of sub-surface oil in sediments and its chronic exposure continues to affect some of the wildlife through delayed population reductions, indirect effects and trophic interactions 20 years beyond the acute phase of the spill.
It then goes on to stay that
Four decades after the oil spill In Wild Harbor (USA), Spartina alterniflora beds had a reduced stem density and biomass and mussels in oiled locations showed decreased growth and filtration rates.
According to a Boston Globe story, published at the time of the Deepwater Horizon oil leak in the Gulf of Mexico, in 2010, the Wild Harbor, an oil barge ran aground near Cape Cod in September, 1969, spilling 200,000 gallons of fuel, some of which is still there.
The Boston Globe story noted:
Today, Wild Harbor looks much like any other Cape Cod marsh, but the oil below the surface affects its resiliency. Fiddler crabs normally burrow deep down, funneling oxygen to the roots of marsh grass. Here, they stop digging when they reach the oil, turn sideways, and burrow back to the surface. They also act “drunk’’ from the oil they ingest, and predators can catch them more easily, research shows.
The Woods Hole Oceanographic Institute has been studying the Wild Harbor spill for the past 40 years.
At a recent conference, Dr. John Teal updated scientists on the “multi-decadal effects” of the Wild Harbor spill. According a blog on the conference:
At the time of the 1969 spill, lobsters, clams, and fish died by the thousands, but most people believed the harm would be temporary, reflecting the conventional wisdom of the time. Barge owners and oil industry experts even told residents that most of the oil would evaporate and any damage would only be short-lived. However, researchers at WHOI were not so sure and immediately began cataloging species and tracking where the oil was and kept at it for years. The researchers understood that the immediate, short term effects of oil pollution were already obvious and fairly well-understood, but that everyone was rather ignorant about the long-term and low-level effects of an oil spill….
Beginning three to five years after the spill, marsh grasses and marsh animals were again occupying most of the oiled area. An observer unfamiliar with Wild Harbor would not have been able to visually detect the oiled areas after just 10 years, and by the second decade after the spill, the marsh’s appearance had returned to normal. However, the WHOI researchers pointed out that for more than a decade after the spill, an oil sheen still appeared on the surface of the water when mud from the most heavily oiled parts of the marsh was disturbed….
In 2007, WHOI researchers documented that a substantial amount of moderately degraded petroleum still remained within the sediment and along eroding creek banks of the marsh oiled in 1969. They also demonstrated that the ribbed mussels that inhabit the oiled salt marsh, and are exposed to the oil, exhibited slower growth rates, shorter mean shell lengths, lower condition indices, and decreased filtration rates even when placed in a healthy marsh. Researchers have also documented detrimental effects of the 1969 oil spill on the salt marsh plants themselves.
Long-term effects on the population in the aquatic environment (especially on mobile fauna) are especially difficult to confirm. Benthic [bottom dwelling] invertebrates may be more at risk than fish species due to the fact that more or less sessile organisms are likely to suffer higher initial rates of mortality and exhibit long recovery times as a result of
exposure to oil-saturated habitats.
Nearshore demersal [bottom-dwelling] fish can also suffer from long-term chronic exposure, as indicated in masked greenlings and crescent gunnels by biomarkers on hydrocarbons 10 years after the Exxon Valdez spill. Mortality in sea ducks and sea turtles due to chronic exposure was also reported many years after the spill and other results indicate that effects on cetacean populations can last beyond 20 years after the acute exposure phase.
As for the recovery of the economy after a spill, Genivar notes it is based “on the time required for effected industries to be fully restored to pre-spill conditions.
The length of time required is influenced by the duration of the aquatic area closures (e.g. commercial fisheries, recreational fisheries), the public perceptions on seafood safety and the perceived effects of the aesthetic quality of the environment. Even after the full ecological recovery of the aquatic resources, fisheries can be far from reestablished, as is still the case for herring fisheries in the Exxon Valdez spill area…
As reviewed by Genivar, negative perceptions associated with the quality of fishery products, even for fisheries that have not been contaminated and also for regions not directly affected by the spill, can be far more important than the direct economic losses. This also holds true for the tourism sector and all other related spinoff sectors.