Plastic nurdles have been found in 84% of important nature sites surveyed in the UK.

Nurdles are tiny pellets that the plastics industry uses to make larger products. They were found in 168 of 195 sites of special scientific interest (SSSIs), so named because of the rare wildlife they harbour. They are given extra protections in an effort to protect them from pollution.

The environmental charity Fidra, however, has been running nurdle hunts at SSSIs across the UK since 2013, and found pellets in 84% of them.

It also found nurdles in six national parks: Loch Lomond & the Trossachs, North York Moors, New Forest, Pembrokeshire Coast, Eryri (Snowdonia), and South Downs.

They are produced at sites around the UK, including Grangemouth in Scotland, and transported by land and sea to be melted down to make almost all of our plastic products. They are lost into the environment by mismanagement in the supply chain – namely, by being accidentally spilled. It is estimated that as many as 53bn nurdles could be lost into the environment in the UK each year.

The worst-affected areas include theRiver Itchen in Southampton, including the Chessel Bay nature reserve, and the Firth of Forth in Scotland.

Nurdles are dangerous for the environment because they are made of plastic and can contain toxic chemicals. Because they are small, animals can mistake them for food and are poisoned by them. They also break down to become microplastics, which enter the human food chain and are dangerous for human health as well as wildlife.

Fidra’s senior project officer, Megan Kirton, said: “It is shocking to see nature reserve and protected areas around the UK impacted by plastic pellet pollution. These precious sanctuaries are being contaminated by preventable industrial pollution.’’

Fidra is asking governments across the world to coordinate policy on nurdles, and to introduce legislation to force good practice and stop spills in the supply chain. It also wants the International Maritime Organization to introduce robust mandatory measures to ensure nurdles are safely transported and not lost at sea.