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Monday 21 October 2019

A plastic tide: combatting the scourge of microplastics in our seas and rivers

Stark message: Plastic bottles and other rubbish washed up in Co Cork. Photo: Education Images
Stark message: Plastic bottles and other rubbish washed up in Co Cork. Photo: Education Images
John Meagher

John Meagher

It was hailed as one of the finest wildlife television series ever made and at the end of the final episode of BBC's Blue Planet 2 last December, David Attenborough issued a plea: "The future of humanity - and all life - now depends on us."

Earlier, viewers had watched aghast as the scale of the plastic pollution in the world's oceans was laid bare. It depicted albatross parents unwittingly feeding their chicks plastic and mother dolphins potentially exposing their newborn calves to pollutants through their contaminated milk.

For many, it was an eye-opener about the harm that plastics - and our dependence on them - have caused to marine life all over the world.

But it was no surprise to Karin Dubsky of Trinity College Dublin. The founder of Coastwatch Europe, the German-born campaigner is one of the country's foremost experts on how this island nation has been relentlessly polluting our seas and rivers with plastic.

"Thirty years ago," she says, "the huge concern was oil spills, but now it's plastic and it's having a hugely detrimental effect. We've seen increased mortality in many species due to ingestion and entanglement."

While there's some commendable volunteer work being conducted to clean up plastic litter in several coastal areas throughout the country, Dubsky insists it's only scratching the surface. "It's impossible to underestimate the impact that microplastics are having on marine life," she says. "It's causing havoc."

Microplastics are defined as being less than 5mm in size and there are countless trillion of them in the world's waters. Together with 'microbeads' - a form of plastic used in several industries, including cosmetics where they're used in exfoliating products - they are ingested by seafood that we readily consume.

That's a huge cause for concern, Dubsky insists. "There was a study by students from NUI Galway which looked at muscles caught on the west coast, and while some had some plastic contamination, others were very heavily contaminated. And we're eating them."

The same study also uncovered evidence that Dublin Bay prawns (Norway lobster) caught on the west coast also were contaminated by plastic.

Plastic is not biodegradable and the smaller it gets, the greater the trouble it causes to marine life - everything from a tiny plankton to an enormous whale.

But larger plastics can be hazardous, too. Last year, there was shock when a photo emerged of naturalists in Norway displaying the 30 large plastic bags that had been found in the stomach of a beached whale.

Dubsky was one of the primary campaigners for the introduction of the plastic bag levy and she says it's had a noticeable impact on our coastline. "When we conduct surveys now, there's only a fraction of the plastic bags that we used to see."

Last year, Coastwatch found two plastic bags per site surveyed, rather than 18 bags in the same areas in 2004, two years after the levy was introduced. "It's certainly helped change people's behaviour, and it's had a direct improvement when it comes to our coastlines. We need to introduce more incentives."

One of the most significant of the bigger plastic pollutants on Irish coasts are drink bottles and their lids. "If we had a deposit-return system for bottles, it would transform the situation," she says. "In Germany, where such a system is in place, you almost never see plastic bottles littering their shores and towns."

And the problem is a significant one. In a Coastwatch survey last autumn, an average of 18 plastic drinks bottles per 500m of shore were found, and while it is the lowest number recorded since the early 1990s here, it is still indicative of a culture where many of us still seem happy to litter the natural environment.

"We have to put pressure on retailers and manufactures not to use plastics. There is a direct link between the needless use of plastic to wrap fruit and vegetables in our supermarkets and the amount of plastic that's polluting our waters," Dubsky says.

But she's keen to stress it's not just the consumer who's to blame. The commercial fishing industry has played a big part in plastic pollution thanks to its use of 'dollies' - plastic coatings for the bottom of dragnets to preserve their longevity - and traditional non-plastic lobster and crab traps have been widely replaced with plastic ones and some of them wind up on the sea floor.

"You need only go out to Howth (Co Dublin) to see all these plastic traps lined up at the pier."

Quite how much plastic is in the world's oceans remains a mystery, although there were suggestions this week from international scientists that plastic in the oceans may cumulatively equate to the total landmass of Mexico.

"And all this has happened in the space of about 50 years," Karin Dubsky says. "It's only in that time that plastics have become commonplace. But we have the knowledge now of the harm they are causing and it is up to each and every one of us to take action and reduce or plastics usage."

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