From road to sea: Exploring the biological effects of tyre particles in marine invertebrates

Tyre wear particles are anthropogenic particulates that stem from the abrasion of synthetic rubber tyres on road surfaces. It is estimated that over 3.4 million tonnes of tyre wear particles are released globally each year. These particles can become airborne or enter highway drainage systems, often resulting in their deposition within the natural marine environment. Tyres contain high concentrations of labile additives, including zinc oxide, antioxidants and plasticizers, that have proven toxic in leachate studies, however the risk posed by tyre particulates themselves is less evident, nor is it clear whether "greener" iterations of tyres may prove any less toxic to aquatic biota. This PhD will undertake pioneering ecotoxicological research to explore the mechanisms underpinning tyre particle toxicity, with a view to identifying greener, safer-by-design options for tyres. The planned work aims to improve our predictions of the risks posed by tyre wear particles, with wider relevance for understanding the fundamental ways in which anthropogenic stressors affect organisms and will address the overarching research question of "What are the physico-chemical drivers of tyre particle toxicity and might alternative tyre compositions prove less toxic?". Across the project, you will work with the supervisory team to co-develop ecotoxicological studies to evaluate the relative toxicity of different tyre particles, including "greener" variants. Exposure studies will use representative, fully-characterised tyre wear particles, in combination with ecologically important marine invertebrates, such as the pelagic copepod Calanus helgolandicus and the epibenthic mussel Mytilus edulis. The adverse risk of tyre particles and tyre leachates will be assessed on a range of biomarkers across the biological hierarchy to elucidate potential modes of action and adverse outcome pathways.