Turning the tide on plastic pollution

Plastics are worrying water companies too. As well as the potential for plastic in the domestic water supply, there’s concern that it may be finding its way back onto farmland in sewage sludge used as a soil conditioner.

Despite the growing concern, though, we’re still at a relatively early stage of quantifying where all this plastic comes from.

The usual suspects - bottles, bags, coffee cups - are undoubtedly part of the problem. Under the UV rays of the sun, the chemical bonds that hold these larger plastics together will eventually break apart, producing lots of tiny fragments called microplastics.

But domestic litter is only part of the story. A 2016 study in southern England’s Thames basin found that plastic washed into the river from fading road surface paint was making a significant contribution downstream of urban areas.

"If you’re driving along the road looking for a parking spot and thinking that the yellow lines are looking faded, that’s a sure sign that the paint has gone somewhere – most likely down the drain," said Ormerod.

Synthetic clothing fibres, tyre wear and cosmetic goods have also been implicated. But what’s not clear yet is just how much of the problem each of these different sources is responsible for.

Ormerod thinks this gap in our knowledge is hampering efforts to tackle the problem.

"We have a large blind spot," he said. "We need to invest in understanding the sources and the environmental loads of different materials. What then happens to these materials? How much is ingested by organisms? How far does it go up food webs? What effects does it have along the way? Does it reach us in the food we eat or the water we drink?

"About two years ago now, our research group attended a workshop convened by the Environment Agency to make an assessment of the science of plastics in the freshwater and river catchment environment. We gave our understanding a mark of one or two out of ten, so we've quite a long way to go."

The success of the plastic bag charge has led to experiments on other single-use plastics.

Bewley’s coffee company approached Poortinga and his team to help them reduce the use of disposable coffee cups in their cafes at university and business sites — coffee cups typically have a plastic lining to keep the heat, and the coffee, inside the cup.

In 12 cafes, they trialled three measures — environmental messaging, provision of sustainable alternatives, and financial incentives.

All three measures were effective, especially working in combination, and had no adverse impact on sales to speak of. But the financial incentives only worked when presented as a charge, rather than as a discount.

"People are more sensitive to losses than to gains," explained Poortinga. "If you gain an extra 10p, most people wouldn’t be bothered about it. But if you have to pay an extra 10p, that’s seen as a loss. It’s basically the same thing, it’s just framed in a different way."

Poortinga warns against assuming that the same measures will work for different plastic products — for behaviour changes that ask more of the consumer, additional charges may prove less effective. He also cautions against expecting too much of the consumer too soon.

"You can always bring a bag," he said. "People have a bag in the back of their car, or in their work bag. It’s very easy to do. It’s a different matter to have a reusable coffee cup in your bag, together with a shopping bag and a reusable bottle for water, for example. It can become unrealistic.

"It’s not only the consumer that has to change their behaviour. It’s also the government that has to do the right thing in terms of policy and regulation. It’s also the retailers that have to do their bit. If we’re talking about plastic packaging, for example, or single use packaging, that is the responsibility of the retailers."

Retailers’ attitudes seem to be changing too. Following the success of Blue Planet II, The No Straw Stand say they’re now being approached by businesses unprompted.

In interviews conducted before and after the plastic bag charge was introduced, Poortinga’s team detected a similar shift in attitudes among consumers.

"People told us that, since the charge was introduced, they notice now how much plastic they’re using on a day-to-day basis," he said. "They mention plastic bottles and coffee cups and all these different things. I think now the climate is right to do something about single-use plastics and packaging."

This has come alongside new investment in research and innovation. As well as the causes of plastic pollution, researchers are urgently trying to understand its health effects on the ever growing list of species it inhabits, including our own.

They’re also looking at new ways to tackle the plastics that already exist. During recent experiments at the University of Portsmouth, researchers inadvertently engineered a plastic-eating enzyme, offering hope of a new method for decomposing petroleum-based plastics.

Each day, meanwhile, plastic continues to wash into rivers and seas around the world, eventually spreading to every corner of the ocean.

Some will become entangled in the digestive systems of wildlife. Some will make its way through the food web — maybe even as far as our plates. Some will simply linger at sea, for centuries or millennia to come, in ever thickening swirls of plastic soup.

The time to turn the tide on plastic, it seems, is fast ebbing away.