Conservation comment: Drastic plastic catastrophe

Major threat: Some of the plastic found in one square metre of sand.

By Margie Beautrais

Seaweek – Kaupapa Moana is a nationwide week-long celebration of the sea. This year it takes place from Saturday to Sunday, March 3-11 with the theme of Toiora te Moana – Toiora te Tangata – Healthy Seas, Healthy People. Activities all around New Zealand have been organised to encourage people of all ages to renew their connection with the sea and get to know more about the marine environment.

In Whanganui on Saturday, March 10, a public beach clean-up of the area between the Duncan Pavilion and the North Mole will be held, starting at 1pm with a briefing in the Rangiora St carpark. Participants will be given free bags and gloves to use and organiser Josie Verhaaren invites participants to stay on afterwards to enjoy some beach activities.

Although it is always possible to find many bags of rubbish along Castlecliff Beach, it is generally much cleaner than many beaches around the world. Whanganui locals regularly pick up rubbish on their daily walks and much of the rubbish found is likely to be plastic.

A United Nations report on marine plastic pollution estimates that in just one year (2010), between 4.8-12.7 million metric tons of plastic found their way into our oceans.

Plastic debris is transported by ocean currents around the entire globe. It is found everywhere; on the shores of uninhabited islands, in Arctic ice, in the deep ocean and floating on the sea surface.

The ecological impact of marine plastic is significant. Most of us will be familiar with images of dolphins, seals and turtles entangled in plastic rubbish, and dead albatrosses with their stomachs full of plastic litter. These pieces of macro-plastic break down into smaller fragments, described as micro-plastics. They are frequently ingested by sea-creatures that mistake them for tasty marine life. The plastic then clogs their guts, causing starvation. Microscopic pieces of plastic are now being found in fish and shellfish caught for human consumption, with unknown consequences for our long-term health.

Marine plastic is a worldwide issue. Because oceans are all connected, this problem has no national boundaries and we all share the consequences. In New Zealand, we often pride ourselves on being "clean and green", and in comparison with other countries, our beaches look reasonably free of rubbish.

Look closer, however, and it may be a different story. Just last week a team surveying plastic from three 1 x 1 metre squares of sand at Oriental Bay in Wellington identified 230 pieces of macro-plastic (pieces large enough to pick up easily), 146 micro-plastics (tiny pieces) and 2412 plastic nurdles (tiny plastic balls used for creating plastic items in manufacture).

One of the challenges to everyone who joins in the Castlecliff Beach clean-up this weekend will be not only to pick up the macro-plastics, which are relatively easy to spot and easy to grab, but to find and remove the tiny, seemingly insignificant micro-plastics dotted along the shore. They may seem small and unimportant, but their environmental impact is huge.

Margie Beautrais is Educator at Whanganui Regional Museum.