Retention ponds can ‘substantially reduce' impact of tire-wear emissions

London – UK scientists have found that retention ponds and wetlands constructed as part of major road schemes can reduce the quantities of tire particles entering the aquatic environment.

The joint study between University of Plymouth and Newcastle University analysed samples collected alongside some of the busiest routes in the English south-west and midlands regions.

The aim was to establish if existing drainage measures in place along parts of the UK’s strategic road network have the potential to halt the spread of tire-wear emissions.

According to the University of Plymouth, tire wear particles (TWPs) were discovered in each of the 70 samples taken, confirming the findings of previous research about “considerable environmental threat” posed.

However, added the university's 12 April release, the presence of wetlands and retention ponds led to an average reduction of almost 75% in the mass of TWPs being discharged to aquatic waters.

The study also found that TWPs significantly outweighed other forms of microplastics, such as plastic fibres and fragments, in the samples collected. These materials were also largely removed.

To gauge this, the study used a method developed by Dr Geoff Abbott, reader in organic geochemistry in the School of Natural and Environmental Sciences (SNES) at Newcastle University.

The “breakthrough method” uses pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to detect tire-derived particles in the environment, said the release.

The approach “can unravel and quantify the monomeric components of microplastics in the environment,” explained Abbott.

“We used it to identify specific components of micro- and nano-plastics that can be unequivocally linked to vehicle tire tread,” he added.

Researchers could, therefore, “get hard numbers” on the total amount of TWPs collecting in the influent, effluent, and sediments of the retention ponds and wetlands analysed in this study.

The findings, according to the research team, are significant as they could offer an effective way to mitigate potential environmental impacts of TWPs on a global scale.

However, the number of these roadside features is small compared to the total road network, according to senior author professor Richard Thompson OBE FRS.

“Our earlier work has shown substantial quantities of tire wear particles are dispersed by wind rather then water,” he explained.

In conclusion, Thompson said more systemic solutions should be sought, “perhaps via improved vehicle tire design.”