C. Matter and Energy · FluidsFluid Spills: Impacts and Cleanup
C1.2 C2.2 C2.1 A1.1 A1.2 A1.5 A3.2About 55 minutes
Learning goals- I can explain how the properties of fluids (density, viscosity, temperature) affect a spill and its cleanup.
- I can assess the environmental and social impacts of fluid spills, including impacts on First Nations, Métis and Inuit communities.
- I can describe cleanup methods and explain why cleanup is costly and technically difficult.
- I can test cleanup methods in a model spill and communicate my results.
Words to know
spill
An accidental release of a fluid, such as oil, fuel or a chemical, into the environment.
remediation
The long-term work of cleaning up and restoring land or water after pollution.
boom
A floating barrier used to stop oil on water from spreading.
skimmer
A device that scoops or sucks floating oil off the surface of water.
sorbent
A material that soaks up or holds on to a liquid, such as oil.
diluted bitumen
Very thick oil from the oil sands, mixed with a lighter fluid so it can flow through a pipeline.
food sovereignty
A community's right to healthy food from its own lands and waters, harvested and shared in its own ways.
When fluids escape
Fluids are useful because they flow. But that same property makes them hard to control when something goes wrong. A cracked pipeline, a train derailment, a sinking boat or a leaking tank can release oil, fuel or chemicals that flow into soil, rivers and lakes, and then spread.
In this lesson you'll use what you know about density, viscosity and temperature to understand spills, and you'll weigh their impacts on people and the environment.
Fluid properties decide how a spill behaves
- Density. Most crude oils and fuels are less dense than water, so they float and spread into a thin layer on the surface. But some heavy oils, such as diluted bitumen, can sink once the lighter fluid mixed into them evaporates and they pick up sand and mud. Sunken oil is much harder to find and remove.
- Viscosity. Light, runny fuels (like gasoline) spread quickly and partly evaporate into the air. Thick, viscous oils spread more slowly but stick to rocks, plants and animals and are hard to wash off.
- Temperature. Cold water makes oil more viscous, and it slows down evaporation and the natural breakdown of oil by microbes. In Canada's North, ice can trap oil underneath, where it is very hard to reach.
- Flow of the water. A fast river carries a spill downstream quickly, sometimes many kilometres in a day, so communities downstream may have little warning.
Density decides where spilled oil goes. Floating oil can be reached by booms and skimmers; oil that sinks to the bottom is much harder to find and remove. (Simplified.)Impacts on the environment
- Birds: oil soaks into feathers, which then can't keep out water or hold in warmth, so birds can die of cold.
- Fish, shellfish and plants: oil and fuel can poison them, coat them, or cut off oxygen.
- Shorelines and wetlands: oil sticks to rocks, sand and roots and can remain for years.
- Drinking water: a spill upstream can force towns to shut their water intakes.
Impacts on people and communities
Spills affect jobs in fishing and tourism, drinking water, health, and the cost of cleanup. For First Nations, Métis and Inuit communities, the impacts can be especially deep:
- Many communities harvest fish, game, plants and medicines from the land and water. A spill can make these foods unsafe, which harms food sovereignty, health and the passing on of knowledge to young people.
- Lands and waters are tied to culture, ceremony and identity. Damage to them is not only an economic loss.
- Some communities are remote, so emergency crews and equipment take longer to arrive, and buying replacement food or water is very expensive.
- Indigenous Nations have rights to their lands and waters, and many say they must be part of decisions about pipelines, shipping and cleanup.
Many First Nations, Métis and Inuit communities run Guardian and monitoring programs, where community members watch over lands and waters, test water and wildlife, and respond to problems, using both Indigenous knowledge and Western science.
Two Canadian examples
The North Saskatchewan River (2016). In July 2016, a Husky Energy pipeline near Maidstone, Saskatchewan, leaked about 225,000 litres of heavy oil mixed with a lighter fluid. Some of it reached the North Saskatchewan River. Floating booms did not fully contain it, and the cities of North Battleford and Prince Albert had to shut their water intakes and find other water supplies. First Nations along the river raised concerns about fishing, harvesting and ceremonies. The company was later fined.
The English–Wabigoon River (1960s and today). In the 1960s, a chemical plant at a paper mill in Dryden, Ontario, released mercury, a liquid metal, into the English–Wabigoon River system. Mercury built up in fish downstream. Grassy Narrows First Nation and Wabaseemoong Independent Nations, which relied on fish for food and on fishing and guiding for jobs, have lived with the health, economic and cultural effects for generations. Community members have spent decades pressing governments for cleanup, health care and compensation. This case shows that some spills and releases have impacts that last far longer than any cleanup crew.
The river's flow carried the oil downstream from the spill toward the cities that take their drinking water from the river.| Cleanup method | How it works | Limits and challenges |
|---|
| Booms | floating barriers that hold oil in one place | fail in strong currents, waves or wind; don't stop oil below the surface |
| Skimmers | scoop or suck floating oil off the surface | slow; work poorly with very thick or very thin oil, or in ice |
| Sorbents | pads or materials that soak up oil | become waste that must be safely disposed of |
| Dispersants | chemicals that break oil into tiny droplets that mix into the water | the oil is still in the water; the chemicals themselves can harm wildlife; often restricted |
| Controlled burning | burning thick floating oil on the water | creates smoke and air pollution; needs calm conditions |
| Bioremediation | microbes that break oil down, sometimes helped with nutrients | slow, especially in cold water |
| Dredging and soil removal | digging up oily mud or soil | very costly; disturbs habitats; the removed material must go somewhere |
Common cleanup methods. No method removes all of the spilled fluid.Why cleanup costs so much
Cleanup needs trained crews, boats, equipment, aircraft, testing labs, waste disposal and years of monitoring. Remote locations, cold weather, ice and oil that sinks all add cost and time. In Canada, the idea that the polluter pays means the company responsible is expected to pay for the cleanup, but people still lose things that money can't fully replace.
Worked exampleLet's assess a spill
Use the 2016 North Saskatchewan River spill to model an impact assessment.
- Step 1. Fluid properties. Heavy oil mixed with a lighter fluid. The light part can evaporate; the heavy part is viscous and sticky. The river's flow carried oil downstream.
- Step 2. Environmental impacts. Oil on the river and its banks; risk to fish, birds and other wildlife along the river.
- Step 3. Social impacts. Two cities had to shut their water intakes. First Nations along the river raised concerns about harvesting and ceremonies. People worried about the safety of the river.
- Step 4. Economic and technical challenges. Cleanup crews, booms and long-term monitoring were costly. Booms in a flowing river did not hold all of the oil. Cities had to pay for other ways to get water.
- Step 5. Judge and recommend. Ideas: better leak detection on pipelines, faster shut-off valves, emergency plans made with downstream communities, including First Nations, and backup water supplies for towns.
The spill harmed a river that many people and communities depend on, showed the technical limits of booms in moving water, and cost a lot to clean up. Better prevention and planning with all affected communities are the strongest ways to reduce future impacts.
Hands-on activityModel oil spill cleanup
Use only cooking oil, never motor oil or any other fuel. Dish soap is not food; keep it out of eyes and mouth. Ask a grown-up to help set up and clean up.
You need: a baking pan or large plastic tub, water, 30 mL (2 tablespoons) of cooking oil mixed with 1 teaspoon of cocoa powder (so you can see it), and "cleanup tools": a piece of yarn or string (boom), a spoon (skimmer), cotton balls and paper towel (sorbents), a few drops of dish soap (dispersant), a craft feather (or a clean feather from the store), a measuring spoon and a cup.
- Fill the pan with about 3 cm of water. Gently pour the oil in the middle. Observe: does it float or sink? How fast does it spread?
- Dip the feather in the oil for a moment. How does it look and feel? Can you wipe it clean with a paper towel?
- Use the yarn boom to surround the oil. Then try the skimmer, then the sorbents. Collect what you remove in the cup.
- Gently blow across the water to make waves. Does the boom still hold?
- Finally, add 2 drops of dish soap to what's left. What happens to the oil?
- Results: estimate how much of the 30 mL you recovered. Which method worked best? Which was hardest?
- Communicate: write a short report or make a poster about what your model shows about real spills, including its limits (a pan is not a river).
What to look for: the oil floats and spreads into a thin layer (less dense than water). The feather gets clumped and is hard to clean. The boom works in calm water but oil slips past with waves. You probably can't recover all 30 mL. The soap breaks the oil into small droplets that mix into the water, so it looks cleaner, but the oil is still there.
Safety and clean-up: wipe spills right away (oily floors are slippery). Put used cotton and paper in the garbage. Don't pour the oily water down the drain: a grown-up can soak it up with paper towels and put them in the garbage.
Your turn
1Why does most spilled crude oil float on water?
Most crude oil is less dense than water.
2Why can diluted bitumen be harder to clean up than oil that floats?
After the lighter fluid evaporates and the bitumen picks up sand and mud, it can become denser than water and sink, where booms and skimmers can't reach it.
3How does cold water affect a spill?
Cold makes oil more viscous and slows evaporation and breakdown by microbes, so the oil lasts longer. Ice can trap oil underneath.
4Name two cleanup methods and one limit of each.
Any two, for example: booms: fail in waves and strong currents; skimmers: slow and poor with very thick oil; sorbents: become waste; dispersants: oil stays in the water and the chemicals can harm wildlife; burning: air pollution; bioremediation: slow in cold water.
5Give two reasons spills can affect First Nations, Métis and Inuit communities especially deeply.
Any two: many depend on harvesting fish, game and plants from the land and water (food sovereignty and health); lands and waters are tied to culture, ceremony and identity; remote communities wait longer for help and pay more for replacement food and water; their rights to lands and waters are affected.
6What does remediation mean?
The long-term work of cleaning up and restoring land or water after pollution.
More practice: warm-up
To stop floating oil from spreading.
A material that soaks up a liquid such as oil.
3Does oil spread faster on calm water or does it stay in one spot?
It spreads into a thin layer across the surface.
4What liquid metal was released into the English–Wabigoon River system?
5What do community Guardian programs do?
Community members watch over lands and waters, test water and wildlife, and respond to problems.
More practice: on your own
1Why do oiled birds often die even if the oil isn't poisonous to them right away?
Oil makes their feathers clump, so they can't keep water out or hold in warmth. The birds get too cold (and may not be able to fly or float well).
2In your model spill, the dish soap made the water look cleaner. Was the spill really cleaned up? Explain.
No. The soap broke the oil into tiny droplets that mixed into the water. The oil is still there, just spread through the water instead of floating on top.
3Why did the cities of North Battleford and Prince Albert shut their water intakes in 2016?
Oil from the pipeline leak was flowing down the North Saskatchewan River, which they used for drinking water. Shutting the intakes kept oil out of the water supply.
4Give two reasons spill cleanup in the Arctic is especially difficult.
Any two: cold makes oil more viscous and slows its breakdown; ice traps oil and blocks boats and skimmers; communities are remote, so equipment takes a long time to arrive; long dark winters and storms.
5Why might a fast-flowing river spill affect more communities than a spill in a small pond?
The river's flow carries the oil downstream quickly, so it can reach many towns and communities, sometimes far away, before it can be contained.
Challenge
1The Grassy Narrows and Wabaseemoong mercury case began in the 1960s, but its impacts continue today. Explain why some spills and releases have such long-lasting impacts.
Mercury doesn't break down; it stays in river sediments and builds up in fish over time. People who rely on fish for food are exposed for years. Lost fishing and guiding jobs, health problems and harm to culture and the passing on of knowledge last across generations, and cleaning contaminated sediment is very difficult and costly.
2Prevention or cleanup: where would you spend money to reduce the harm from pipeline spills? Give a reasoned answer.
Model answer: most money should go to prevention: inspections, leak detection sensors, automatic shut-off valves, and routes that avoid key rivers. No cleanup method recovers all spilled oil, cleanup is very costly, and some harms (to health, culture and wildlife) can't be undone. Some money must still go to preparedness: trained crews and equipment near rivers, and emergency plans made with downstream communities, including First Nations. Look for: a clear choice, reasons using evidence from the lesson.
3Using fluid properties, explain why the same amount of spilled gasoline and heavy oil would behave differently on a lake in summer.
Gasoline has low viscosity and much of it evaporates quickly, so it spreads fast and thin, and pollutes the air as it evaporates, but less remains on the water. Heavy oil is more viscous, spreads more slowly, evaporates much less, sticks to shorelines and wildlife, and may even sink if it becomes denser than water. Heavy oil usually stays in the environment longer.
Check your understandingQuiz
1. Most crude oil floats on water because it...
2. Why can diluted bitumen sink after a spill?
3. A floating barrier that keeps oil from spreading is a...
4. Which is a limit of using dispersants?
5. Cold water makes spilled oil...
6. Which statement about spills and First Nations, Métis and Inuit communities is accurate?
For parents and teachersBig idea (C1.2): students assess the environmental and social impacts of fluid spills, including impacts on First Nations, Métis and Inuit communities, and the costs and technical challenges of cleanup and remediation. Fluid properties from this unit (density C2.2, viscosity C2.1, temperature) explain how spills behave. The model cleanup is an investigation (A1.2) with a report (A1.5); the case studies use research and real-world problem solving (A1.1, A3.2).
About the case studies: the Grassy Narrows and Wabaseemoong mercury case is a serious, ongoing issue for living communities. Talk about it respectfully and factually; avoid describing the communities only as victims: they have led decades of advocacy for their lands, waters and health. If your child wants to learn more, look for information from the communities themselves and from news sources.
How to help: ask your child to explain the model cleanup results: "Why couldn't you get all the oil back?" Discuss news stories about spills together, using the three impact types.
Common difficulties:
- Thinking cleanup removes all the oil. It never does.
- Thinking dispersants clean water. They hide the oil by spreading it through the water.
- Speaking about Indigenous peoples only in the past tense.
Safety: use only cooking oil in the model, never motor oil or fuel. Dish soap is not food. Don't pour oily water down the drain.