Plastic food containers are most pervasive form of litter, global study finds

Study evaluated more that 12 million litter items found in oceans, coastal locations and rivers

A turtle floats among plastic bags.

Plastic from take-out and convenience food in the form of plates, cutlery, cups and wrapping is the single biggest form of litter polluting the world’s oceans and rivers, according to new research.

In the biggest marine litter evaluation ever completed, scientists at the University of Cádiz in Spain analysed global inventories cataloguing more than 12 million pieces of litter found in and around rivers, oceans, shorelines and the seafloor.

They found eight out of 10 items listed were made of plastic, and 44 per cent of this plastic litter related to take-out food and drinks. Single-use bottles, food containers and wrappers, and plastic bags made up the biggest share.

Just 10 plastic products, also including plastic lids and fishing gear, accounted for three-quarters of the litter – due to their widespread use and extremely slow degradation.


“It was shocking to find out that bags, bottles, food containers and cutlery together with wrappers account for almost half of the human-made objects on a global scale,” said study leader Dr Carmen Morales-Caselles. “We found them in rivers, on the deep seabed, on shorelines and floating off our coasts.”

The scientists said identifying the key sources of ocean plastic made it clear where action was needed to stop the stream of litter at its source. They called for bans on some common throwaway items and for producers to be made to take more responsibility.

The EU has taken effective action on plastic straws and cotton buds in Europe, Dr Morales acknowledged, but this risked being a distraction from tackling far more common types of litter. Their results were based on carefully combining 12 million data points from 36 databases across the planet.

“We were not surprised about plastic being 80 per cent of the litter, but the high proportion of takeaway items did surprise us, which will not just be McDonald’s litter, but water bottles, beverage bottles like Coca-Cola, and cans,” she noted.

“This information will make it easier for policymakers to actually take action to try to turn off the tap of marine litter flowing into the ocean, rather than just clean it up,” she added.

Getting distracted

Straws and stirrers made up 2.3 per cent of the litter and cotton buds and lolly sticks were 0.16 per cent. “It’s good that there is action against plastic cotton buds, but if we don’t add to this action the top litter items, then we are not dealing with the core of the problem - we’re getting distracted,” Dr Morales-Caselles said.

The research published in Nature Sustainability underlines that understanding the products that account for the biggest share of marine litter is crucial to reducing pollution as such knowledge is also needed to ensure responsible production and consumption patterns.

The analysis included items bigger than 3 cm and identifiable – excluding fragments and microplastics. It distinguished between take-out plastic items and toiletry and household product containers.

The highest concentration of litter was found on shorelines and sea floors near coasts. The scientists said wind and waves repeatedly sweep litter to the coasts, where it accumulates on the nearby seafloor. Fishing material, such as ropes and nets, were significant only in the open oceans, where they made up about half the total litter.

Another study in the same journal examined litter entering the ocean from 42 rivers in Europe. It found Turkey, Italy and the UK were the top three contributors to floating marine litter.

“Mitigation measures cannot mean cleaning up at the river mouth,” said Daniel González-Fernández of the University of Cádiz, who led the second study. “You have to stop the litter at the source so the plastic doesn’t even enter the environment in the first place.”

In May, Greenpeace revealed UK plastic waste sent to Turkey for recycling had been burned or dumped and left to pollute the ocean.

The researchers recommended bans on avoidable take-out plastic items, such as single-use bags, as the best option. For products deemed essential, they said the producers should be made to take more responsibility for the collection and safe disposal of products and they also backed deposit return schemes.

"This comprehensive study concludes that the best way to confront plastic pollution is for governments to severely restrict single-use plastic packaging," said Nina Schrank plastics campaigner at Greenpeace UK. "This seems undeniable. We will never recycle the quantity of waste plastic we're currently producing."

Researchers are also trying to understand the ecological effects of plastic pollution. Plastic itself is inert, but often contains toxic additives such as flame retardants, pigments, or chemicals to make plastic more flexible and durable. “These additives are what were worried about,” Dr Morales-Caselles said. Other harmful substances, such as polycyclic aromatic hydrocarbons, can enter ecosystems by sticking to drifting plastic.

Microplastic particles eroded from larger objects can end up the same size as plankton, so marine animals eat them without deriving any nutrition. Smaller, nanoplastic particles may be the most harmful. They can be tiny enough to penetrate tissues though research on their impacts and animals and human is limited.

To stem buildup of debris, many countries have moved to phase out single-use plastics; as of 2018, 127 had passed legislation to regulate plastic bags, according to UNESCO in a report published this week on the level of research on plastic pollution. But given low recycling rates, it found bans will not be enough; biodegradable alternatives will be needed.

Oceanographer Tiffany Straza, the report's deputy editor, told Science magazine there were parallels between plastic pollution and the problem of nuclear waste.

“There was this idea that our scientific knowledge and solutions for waste disposal would catch up while we chased after this advanced technology,” she added. Yet practices for disposing of nuclear waste lagged while nuclear power burgeoned. “I’m not convinced that we’ve fully learned that lesson,” she says. “Are we going to do the same with plastics?” - Additional reporting: Guardian

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times