When land becomes polluted
Land pollution is damage to land and soil caused by waste, chemicals and human activities. Polluted soil can harm plants, animals and people, and pollutants can seep into groundwater or wash into rivers.
Sources of land pollution
| Source | Examples |
|---|---|
| Garbage and litter | Household waste, plastic bags, illegal dumping |
| Agriculture | Pesticides, excess fertilizers, animal waste |
| Mining | Waste rock and tailings containing toxic metals |
| Industry | Chemical spills, factory waste, abandoned industrial sites |
| Construction and demolition | Concrete, wood, drywall, asbestos |
| Oil and gas | Spills and leaks |
| E-waste | Discarded electronics containing lead, mercury and cadmium |
Garbage and landfills
Most garbage in Canada goes to landfills. Modern landfills are carefully engineered to reduce pollution.
| Feature | Purpose |
|---|---|
| Clay and plastic liners | Prevent liquids from leaking into groundwater |
| Leachate collection pipes | Collect polluted liquid that drains through the garbage, for treatment |
| Daily soil cover | Reduces smells, pests and blowing litter |
| Gas collection wells | Capture methane from rotting waste; some is burned to make electricity |
| Monitoring wells | Check groundwater for leaks |
Even so, landfills take up large areas, produce methane (a powerful greenhouse gas), and can leak for decades. Garbage breaks down very slowly in a landfill because there’s little air. Archaeologists digging in old landfills have found readable newspapers decades old.
How long does it take to break down?
| Item | Approximate time |
|---|---|
| Banana peel | 2–5 weeks (when composted) |
| Paper bag | About 1 month |
| Aluminum can | 80–200 years |
| Plastic bag | Hundreds of years |
| Plastic bottle | About 450 years |
| Glass bottle | Possibly a million years |
These are rough estimates, and in landfills breakdown is often slower.
Litter
Litter isn’t just ugly. It:
- harms animals that eat it or get tangled in it
- blocks storm drains, causing flooding
- breaks into microplastics that spread through soil and water
Hazardous waste
Hazardous waste is toxic, flammable, corrosive or reactive. It must never go in the regular garbage.
| Hazardous household waste | Why |
|---|---|
| Batteries | Contain metals and can start fires in garbage trucks |
| Paint, solvents, motor oil | Toxic; pollute soil and water |
| Pesticides and cleaning chemicals | Toxic to living things |
| Fluorescent bulbs | Contain mercury |
| Propane tanks | Can explode |
| Medicines | Return to a pharmacy |
Most communities have special depots or collection days for hazardous waste.
E-waste
Canadians throw away hundreds of thousands of tonnes of electronics each year. E-waste contains toxic substances, but also valuable metals like gold, silver, copper and rare earth elements. Recycling programs recover these materials safely. Old phones and computers should go to e-waste recycling, not the garbage.
Contaminated sites
A brownfield is an abandoned industrial or commercial site, like an old gas station, rail yard or factory, that may have contaminated soil. Canada has thousands of contaminated sites.
| Example | Issue |
|---|---|
| Giant Mine, Yellowknife, NWT | About 237 000 tonnes of toxic arsenic trioxide dust stored underground; a major long-term cleanup is underway |
| Sydney Tar Ponds, Nova Scotia | Decades of steel-making waste; cleaned up and turned into a park by 2013 |
| Old gas stations | Leaking underground fuel tanks |
Cleaning up land
| Method | How it works |
|---|---|
| Excavation | Dig up contaminated soil and treat or dispose of it safely |
| Capping | Cover contaminated soil to prevent contact |
| Bioremediation | Use bacteria to break down pollutants like oil |
| Phytoremediation | Use plants that absorb metals or chemicals from soil; sunflowers have been used to absorb radioactive elements |
| Soil washing | Wash pollutants out of soil |
Cleaned brownfields can become parks, homes and businesses.
What can you do?
- Follow the 3 Rs: reduce, reuse, recycle.
- Compost food scraps.
- Never litter, and join community cleanups.
- Take hazardous waste and e-waste to proper depots.
- Use fewer pesticides and chemicals at home.
- Choose products with less packaging.
Common mistakes
- Thinking garbage breaks down quickly in landfills.
- Throwing batteries in the garbage.
- Thinking out of sight is out of mind. Buried pollution can spread through groundwater for decades.
Try it yourself
- Bury a banana peel, a paper towel, a plastic bag and an aluminum foil square in a pot of soil. Dig them up after a month. What changed?
- Organize a schoolyard litter cleanup. Sort and tally what you find.
- Find your community’s hazardous waste and e-waste drop-off locations.
Quick recap
- Land pollution comes from garbage, agriculture, mining, industry and chemicals.
- Landfills are engineered to contain waste but still have impacts.
- Hazardous waste and e-waste need special disposal.
- Contaminated sites can be cleaned up with methods like bioremediation.
- Reducing waste and disposing of it properly protects the land.