Click image to open full size
Environmental Science
Plastic Pollution and the Ocean
From Single-Use Plastic to Microplastics
Related Tools
Related Labs
Related Worksheets
Plastic pollution in the ocean is a major environmental problem because plastics are durable, lightweight, and used in huge quantities. Many plastic items are used briefly but can remain in nature for decades or centuries. Once plastic enters rivers, beaches, or storm drains, wind and water can carry it to the sea. Ocean plastic harms wildlife, damages habitats, and can affect human food systems.
Key Facts
- Most ocean plastic begins on land and is transported by rivers, runoff, wind, and poor waste management.
- Plastic does not biodegrade quickly, it mainly breaks into smaller pieces called microplastics.
- Microplastics are plastic particles smaller than 5 mm.
- Bioaccumulation occurs when pollutants build up in an organism over time.
- Concentration = mass of pollutant / volume of water, such as mg/L.
- Percent reduction = (original amount - new amount) / original amount x 100%
Vocabulary
- Microplastic
- A microplastic is a plastic particle smaller than 5 millimeters that can be eaten by small organisms and move through food webs.
- Gyre
- A gyre is a large system of rotating ocean currents that can concentrate floating debris in certain ocean regions.
- Bioaccumulation
- Bioaccumulation is the buildup of a substance, such as a pollutant, inside an organism over time.
- Entanglement
- Entanglement occurs when animals become trapped or restricted by plastic items such as fishing line, nets, or packaging loops.
- Runoff
- Runoff is water from rain or melting snow that flows over land and can carry litter, chemicals, and sediments into waterways.
Common Mistakes to Avoid
- Assuming ocean plastic only comes from ships is wrong because most ocean plastic starts on land and reaches the sea through rivers, storm drains, beaches, and wind.
- Thinking biodegradable means harmless is wrong because some materials only break down under special industrial conditions and may still persist in ocean environments.
- Ignoring small plastic pieces is wrong because microplastics can be eaten by plankton, shellfish, fish, and other organisms near the base of marine food webs.
- Counting only visible floating plastic is wrong because plastic can also sink, become buried in sediment, break into microscopic particles, or be eaten by animals.
Practice Questions
- 1 A cleanup team removes 180 kg of plastic from a beach. If 35% of the plastic is bottles, how many kilograms of bottles were removed?
- 2 A water sample contains 240 microplastic particles in 3 liters of seawater. What is the concentration in particles per liter?
- 3 Explain why reducing single-use plastic on land can lower plastic pollution in the open ocean, even for communities far from the coast.