On 19 July 2026, a vessel collision at the Port of Tyne released an estimated 17 tonnes of small plastic pellets, known as nurdles, into the river: around 850 million pellets. Computer modelling by a Newcastle University team, developed as part of advice provided to the Scientific and Technical Advice Cell (STAC), has tracked where those pellets are likely to have gone.

Most were carried out to sea within a few weeks. This began on the first day, and by 3 August around 62% had left the river.

However, a substantial share remained, and by 30 August, 16% were still inside the estuary. Allowing for pellets removed by clean-up teams, an estimated 2.2 tonnes, around one in eight of the pellets released, remained.

A window before high river flows in autumn

River flows in the Tyne have generally been low from July through to the end of September. The researchers expect that a significant increase in high-flow events of autumn and winter could mobilise and flush out some of the pellets still held in the estuary. They strongly recommend that measures to intercept, trap or recover the nurdles are considered before those events, at locations where they can be done safely and effectively.

Dr Matt Perks, who leads Newcastle University's research project into the spill, said: “Because river flows have been so low since July, pellets that moved up the estuary and were deposited have had little to move them on. When elevated river flows arrive, some of that material is likely to be flushed downstream, so now is the time to consider where it could be intercepted. Over the coming months our fieldwork will measure directly how pellets move with the tide, which will let us test and improve these predictions.”

While the estuary findings are robust, the modelling has revealed a more uncertain picture at sea. Once pellets left the river, their paths depended strongly on ocean currents and how much the wind pushed floating pellets directly. In one plausible scenario in the modelling, pellets appear to move first towards northern shores in early August, before shifting south over the following weeks, a broad pattern that appears consistent with recoveries reported along the coast.

However, the researchers say the offshore maps are only possible scenarios, not a definitive record of where individual pellets went, as different assumptions in the modelling produced markedly different patterns of where the nurdles may have gone once offshore.

Dr Seb Pitman, Senior Lecturer in Physical Geography at Newcastle University, said: “Our model reproduces the tide through the Tyne very closely, which gives us real confidence in what it says about the estuary itself. Even after allowing for everything the clean-up teams recovered, more than two tonnes of pellets were still in the river six weeks after the spill. Where the rest went at sea is much less certain, and we've been careful to present those maps as possibilities rather than predictions.”

More information is available at tynenurdles.org.uk.