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Litter Trace – how much plastic really goes to sea?

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How much plastic really goes to sea?

It is widely assumed that 80% of the plastic litter found in the sea comes from land-based sources. UCT are conducting a series of experiments to estimate the proportion of litter coming out of urban catchment areas that washes up on beaches.

Most of the litter in the sea, close to urban areas in South Africa comes from local sources. However, there is a massive mismatch between the estimates of how much plastic is floating at sea (about 250,000 tonnes) and how much ‘leaks’ from land into the sea each year (anything from 5-12 millions tonnes). Even allowing for plastics that sink, either one (or both) of these estimates is wrong, or a lot of the plastic litter coming out of rivers and storm drains is not actually ending up at sea.

Researchers at UCT are conducting a series of experiments to estimate the proportion of litter coming out of urban catchment areas that washes up on beaches. This will entail releasing labelled pieces of plastic and then searching for them along nearby beaches. The study will contrast the movement of plastics with different densities, which likely will show different dispersal patterns.

We ask members of the public to look for these items and to report any they find.

The white plastic blocks measure 12x8 cm and come in two types:

  • hard plastic sheets 3 mm thick with stickers on them bearing a unique item number (0000 to 1199) and information on how to report them.

plastic1

  • polystyrene blocks 30 mm thick that are only labelled with a unique code (A00-F99) because unfortunately our labels don’t stick to expanded polystyrene

plastic2

The researchers need the code number of each item found, together with the location and date where it was found.

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