Unknown quantities of microscopic plastic from discarded products are being washed up on British shores and probably ingested by marine life.
While no definite hazard associated with the pollution has been identified, scientists are concerned it may have the potential to deliver doses of toxic chemicals to vulnerable organisms.
Richard Thompson, lecturer in benthic ecology at Plymouth University, revealed preliminary results from a Leverhulme Trust-funded pilot study at the British Ecological Society conference this week.
It has been estimated that 10 per cent of plastic products end up in the sea. These get broken down into microscopic particles and can persist for many years.
Dr Thompson's team collected sediment from 14 sandy shoreline locations in the British Isles. In every case, they found brightly coloured plastic fibres were abundant in each litre of sand examined.
The four plastics positively identified are acrylonitrile, acrylic, rayon and polyester, all thought to be harmless.
However, Dr Thompson said many were likely to be neutrally coloured particles that would be almost impossible to identify visually.
"I suspect we're missing a lot of material and although we haven't found any particu-larly nasty plastics, they are likely to be there," he said.
Dr Thompson is collaborating with chemists at Southampton and Plymouth universities to develop techniques to determine the total plastic content of sediment.
The team aims to pick out the chemical signatures of individual plastics that could be potentially damaging. Many contain toxic chemicals associated with endocrine disruption, reproductive abnormalities and cancer. The particles are a source and transport mechanism for these substances.
In laboratory tests, Dr Thompson found that barnacles, sandhoppers and aquatic worms ate microscopic plastic particles when they were mixed into sediment and that they accumulated inside their bodies over a number of days. The fear is that such creatures could be slowly poisoned by toxins leaking out of the particles.