Once in the marine environment, tracing microplastics back to their source presents many difficulties. The approach taken in this study by the University of Plymouth was to quantify both tyre particles and synthetic fibres as they enter the marine environment. Three points of entry were considered; release from treated wastewater effluent, direct release from storm water drains adjacent to roads, and deposition from the air within 50 m of roadsides. Samples were collected from replicate sites in the South West of England and the researchers found that tyre particles represented a substantial source of microplastics, that is in addition to previously reported quantities of microplastics from other sources (fibres, fragmentation, microbeads from cosmetics).
“Scientists have long suspected that tyre debris is posing a hidden threat to the marine environment. However, there have been few studies measuring abundance in aquatic environments. Now that we have a clearer indication on quantities, we need to gain a better understanding on transport in the environment and the potential impacts on marine life.” – Prof Richard Thompson from the University of Plymouth.