In keeping with tradition, they are still painting the Forth Bridge – a 132 year old effort that never ends. But in the village of North Queensferry in Fife, under the red steel arches of the cantilever railway bridge – which opened in 1890 and spans the Firth of Forth – lies another seemingly insurmountable task.

A myriad of plastic pieces swirl in the tidal waters and steadily settle along the shore of the estuary. A beach in North Queensferry, a popular tourist spot that is home to the CBeebies program Molly and Mack (and former Prime Minister Gordon Brown), has been found to have the highest concentration of lentil-sized plastic pellets known as nurdles in the UK. , and of all the places currently mapped is one of the most polluted by them in the world.

As I plod along the rocky coast with Heather McFarlane, project manager at the environmental association Fidra, which maps air pollution, she tells me that 600,000 pellets have been collected by volunteers on this small beach in 2018.

But even that figure is a gross understatement of the problem. Digging into the seaweed, which is strewn with plastic bottles, pieces of polystyrene and all sorts of artificial jetsam, the clear, yellow and blue pellets are so densely interwoven that they seem to have formed their own geological stratum.

“There’s nowhere you can stand where there isn’t a nurdle,” McFarlane says.

The Dangers of “Mermaid’s Tears”

Nurdles have been around since plastic was mass-produced: pellets form the basis of nearly every plastic product on earth. When the plastics are created, they are extruded into long, spaghetti-like strands, which are cut into pieces and packaged, often in 25kg bags, then transported around the world.

Unlike constellations of often microscopic pieces of plastic degrading from larger pieces in our rivers and oceans, nurdles are “primary microplastics,” meaning they are constructed that way.

Cheap and designed to be as small as possible for ease of transport, they are susceptible to loss at every step of the plastic supply chain: falling from the back of trucks and onto factory floors, and wash through the sewers into the sea.

Small moments of inattention – combined with the occasional catastrophic loss of shipping containers filled with nurdles – account for the approximately 230,000 tonnes of pellets dumped into the oceans each year, which equates to approximately 10 trillion pellets, or 15 billion plastic bottles.

Beaches around the world are affected, but those concentrated around industrial areas are particularly sensitive. North Queensferry, for example, is only a few miles from Grangemouth, Scotland’s largest container port.