The lifecycle of a plastic bottle
This is the story of three plastic
bottles, empty and discarded. Their journeys are
about to diverge with outcomes that impact nothing less than the fate of the
planet. But they weren't always this way.
To understand where these bottles
end up, we must first explore their origins. The
heroes of our story were conceived in this oil refinery. The plastic in their
bodies was formed by chemically bonding oil and gas molecules together to make
monomers. In turn, these monomers were bonded into long polymer chains to make
plastic in the form of millions of pellets. Those were melted at manufacturing
plants and reformed in moulds to create the resilient material that makes up
the triplets' bodies.
Machines filled the
bottles with sweet bubbly liquid and they were then wrapped, shipped, bought,
opened, consumed and unceremoniously discarded. And now here they lie, poised
at the edge of the unknown. Bottle one, like hundreds of millions of tons of
his plastic brethren, ends up in a landfill. This huge dump expands each day as
more trash comes in and continues to take up space. As plastics sit there being
compressed amongst layers of other junk, rainwater flows through the waste and
absorbs the water-soluble compounds it contains, and some of those are highly
toxic. Together, they create a harmful stew called leachate, which can move
into groundwater, soil and streams, poisoning ecosystems and harming wildlife. It
can take bottle one an agonising 1,000 years to decompose.
Bottle two's journey is
stranger but, unfortunately, no happier. He floats on a trickle that reaches a
stream, a stream that flows into a river, and a river that reaches the ocean. After
months lost at sea, he's slowly drawn into a massive vortex, where trash
accumulates, a place known as the Great Pacific Garbage Patch. Here the ocean's
currents have trapped millions of pieces of plastic debris. This is one of five
plastic-filled gyres in the world's seas. Places where the pollutants turn the
water into a cloudy plastic soup.
Some animals, like
seabirds, get entangled in the mess. They, and others, mistake the brightly
coloured plastic bits for food. Plastic makes them feel full when they're not, so
they starve to death and pass the toxins from the plastic up the food chain. For
example, it's eaten by lanternfish, the lanternfish are eaten by squid, the
squid are eaten by tuna, and the tuna are eaten by us. And most plastics don't
biodegrade, which means they're destined to break down into smaller and smaller
pieces called microplastics, which might rotate in the sea eternally.
But bottle three is
spared the cruel purgatories of his brothers. A truck brings him to a plant where
he and his companions are squeezed flat and compressed into a block. Okay, this
sounds pretty bad, too, but hang in there. It gets better. The blocks are
shredded into tiny pieces, which are washed and melted, so they become the raw
materials that can be used again. As if by magic, bottle three is now ready to
be reborn as something completely new. For this bit of plastic with such humble
origins, suddenly the sky is the limit.
Source: TED Ed – Created by Emma Bryce