What are conventional plastics made from?

fossil fuels. They are generally non-biodegradable.

What is the size limit for a microplastic?

less than 5 mm. Less than 5 mm in length.

Which organisms decompose biodegradable plastics?

bacteria and fungi. They are the decomposers.

What is a bioplastic?

a plastic made fully or partly from biological raw materials. It may be biodegradable or non-biodegradable.

Which strategy reduces plastic pollution?

avoiding single-use plastics. Less plastic used means less plastic lost.

Why does the rate at which a biodegradable plastic decomposes vary from place to place?

it depends on biotic and abiotic factors, such as microorganisms and temperature. Warmth, moisture and the right microorganisms speed it up.

Plastic pollution · Cambridge IGCSE Environmental Management

In plain words

Plastic is useful for the same reason it is a problem: it lasts. A bottle used for ten minutes can stay in the sea for centuries, breaking into smaller and smaller pieces without ever going away.

10 things to know

Conventional plastics are made from fossil fuels and are generally non-biodegradable.
Bioplastics are made fully or partly from biological raw materials, such as plants, and not from fossil fuels. A bioplastic can be biodegradable or non-biodegradable.
Biodegradable plastics are designed to decompose in water or soil. Bacteria and fungi decompose them into water, biomass and gases: carbon dioxide and methane.
Biodegradable plastics decompose at different rates, depending on biotic factors, such as which microorganisms are present, and abiotic factors, such as temperature and moisture.
Non-biodegradable plastics break down over a very long period of time.
Microplastics are pieces of plastic less than 5 mm in length. They form when larger plastics break down, and they are also used in commercial products.
Impacts on marine ecosystems. Visual pollution: plastic litters beaches and the sea. Entanglement: animals are caught in nets, ropes and packaging, and are injured or drown.
Animals mistake plastic for food. It fills the stomach, so the animal starves. Plastics also carry toxic substances, which bioaccumulate in an animal and biomagnify up the food chain.
Strategies: alternative packaging, such as paper and glass; avoiding single-use plastics; safe disposal, so plastic cannot blow or wash into the sea; and recycling.
Legislation and enforcement: bans or charges on plastic bags and other items, with fines for breaking the rules.

Worked example

A turtle is found dead with its stomach full of plastic bags. Explain how this happened and suggest one strategy to prevent it.

A floating bag looks like a jellyfish, which turtles eat. The turtle mistook the plastic for food.
The plastic cannot be digested. It filled the stomach, so the turtle could not feed and starved.
Strategy: a law that bans or charges for single-use bags, so fewer reach the sea.

Tips and tricks

"Bioplastic" and "biodegradable" do not mean the same thing. A bioplastic is made from biological material. It may or may not decompose.
The size limit for microplastics is less than 5 mm in length. Learn the number.

6 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Plastic pollution: 6 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

What are conventional plastics made from?
- fossil fuels (the answer)
- seaweed
- plants
- sand
They are generally non-biodegradable.
What is the size limit for a microplastic?
- less than 5 cm
- less than 5 mm (the answer)
- less than 50 mm
- less than 5 m
Less than 5 mm in length.
Which organisms decompose biodegradable plastics?
- fish and crustaceans
- algae and seaweeds
- insects and worms
- bacteria and fungi (the answer)
They are the decomposers.
What is a bioplastic?
- a plastic that always decomposes quickly
- a plastic found inside animals
- a plastic made fully or partly from biological raw materials (the answer)
- a plastic made from recycled bottles
It may be biodegradable or non-biodegradable.
Which strategy reduces plastic pollution?
- avoiding single-use plastics (the answer)
- using smaller pieces of plastic
- dumping waste further out to sea
- making plastics from fossil fuels
Less plastic used means less plastic lost.
Why does the rate at which a biodegradable plastic decomposes vary from place to place?Stretch
- the plastic changes colour
- the plastic is made in different factories
- it depends on biotic and abiotic factors, such as microorganisms and temperature (the answer)
- sea water stops all decomposition
Warmth, moisture and the right microorganisms speed it up.

6 questions

Tap an answer and you’ll see straight away whether it’s right, and why.

Worksheet

3 questions, 8 marks. Write your answers on paper, then check them.

Plastic pollution

Cambridge IGCSE Environmental Management 0680 · 8 marks · papermunch.org

Name ______________________________ Date ______________

Describe what is meant by microplastics.[2]
Show answerHide answer
Pieces of plastic less than 5 mm in length. They form when larger plastics break down, or are used in commercial products.
I got this one
Describe how biodegradable plastics decompose.[3]
Show answerHide answer
They are designed to decompose in water or soil. Bacteria and fungi break them down. The products are water, biomass and gases (carbon dioxide and methane).
I got this one
Explain three ways in which plastic harms marine animals.[3]
Show answerHide answer
Any three: animals become entangled and are injured or drown; they mistake plastic for food, which fills the stomach so they starve; toxic substances from plastic bioaccumulate in them; the toxins biomagnify up the food chain.
I got this one

Answers: Plastic pollution

1. Pieces of plastic less than 5 mm in length. They form when larger plastics break down, or are used in commercial products.
2. They are designed to decompose in water or soil. Bacteria and fungi break them down. The products are water, biomass and gases (carbon dioxide and methane).
3. Any three: animals become entangled and are injured or drown; they mistake plastic for food, which fills the stomach so they starve; toxic substances from plastic bioaccumulate in them; the toxins biomagnify up the food chain.