Survey reveals tiny plastic scourge hurting sealife

A one-off survey at Wellington's Oriental Bay beach recovered hundreds of pieces of microplastic. Photo / File

Tiny pellets that were supposed to have been made into plastic products have instead been found in their masses around Wellington's marine environment.

Sampling work that recovered hundreds of the tiny "nurdles" of virgin plastic from around the capital's waters and shores, along with large numbers of other microplastics, has highlighted the alarming toll pollution is now having on New Zealand's life-rich blue backyard.

Microplastics are small particles, less than 5mm in diameter, that are either manufactured at that size or result from the physical breakdown of larger plastic pieces.

While there's now plenty of evidence around the impact on animals and ecosystems from large plastic items, notably single-use bags, less is known about damage wrought by this much smaller scourge, now found in even pristine polar waters.

Studies show they may hurt organisms that ingest them - which include fish that we ourselves eat - with wider and troubling implications for the ecosystems they live in.

"The impact may not come directly from the plastic itself but rather all the chemical toxins these plastics take up from their environment," ESR environmental scientist Dr Olga Pantos explained.

The hydrophobic nature of plastics made them effective at absorbing chemical contaminants, making them more toxic.

"Therefore if the plastic is ingested by an animal they are taking in a high dose of contaminants which may affect them in various ways."

A sample of some of the nurdles collected from just one square metre of sand at Wellington's Oriental Bay beach. Photo / ESR

Scientists say pin-pointing the origin and distribution of microplastic pollution could make it possible to develop new strategies to combat the problem - and the few sampling studies so far undertaken here have shown the extent of it.

The most recent, made during the Pollution Use Resistance Education (PURE) Tour and Waka Odyssey Festival earlier this year, collected samples between Hawke's Bay and Wellington, with further surveys on the city's Oriental Bay beach.

A collaboration between Algalita South Pacific, 5 Gyres Institute, Tina Ngata and others, the sampling was done using specially-designed nets that were pulled behind ocean-going waka.

Some of the microplastics recovered from a trawl of Wellington Harbour. Photo / ESR

What was collected from the trawls and the beach survey was later sent to Pantos, who worked with University of Canterbury masters student to sort through plastics large enough to be seen.

The trawls recovered 21 microplastic fragments - mainly polyethylene and polypropylene, which, along with PET, polystyrene and PVC, also comprised the nearly 300 pieces found on the beach.

Most of the samples also came in the form of multi-coloured nurdles, which have been found on our beaches since the 1970s, and may have entered the environment through poor transport or handling.

Pantos said, as the survey wasn't a comprehensive one, it was difficult to extrapolate the results elsewhere to centres such as Auckland.

Some of the plastic was collected during trawls by Hawke's Bay-based waka Te Matau a Maui. Photo / Raihania Tipoki, Facebook

"Research into this area is fairly new to New Zealand and there is a lot to learn on how much plastic is out there, not only in the marine but also freshwater and terrestrial ecosystems, and understand the risks they pose to ecosystems, animals and potentially humans."

New Zealand has moved to ban microbeads, but the wider problem of microplastics couldn't be tackled in the same way.

Current legislation encouraged product stewardship and environmental responsibility at the beginning of a product's life cycle.

Five ways you can combat plastic pollution

1. Choose to refuse single-use plastic where possible.
2. Find ocean-friendly alternatives. A quick Google search also offers lots of cheap and easy DIY options.
3. Re-use everything you possibly can.
4. Get creative and fix or make your own products.
5. Educate yourself: watch documentaries, read articles and get involved with groups.