Revealing the hidden identity and toxicity of priority chemical pollutants released during microplastic degradation and additive leaching in marine...

...and coastal environments.

Project Summary: Micro- and nanoscale plastics produced from the decomposition of marine plastic debris pose a severe threat to marine and coastal ecosystems. Microplastics (MPs) are known to undergo degradation in the marine environment through abrasion (physical), advanced oxidation processes (abiotic), and biological degradation (biotic), resulting in the leaching of additives not chemically bound to the polymer matrix.

These transformations are difficult to reproduce under laboratory conditions; they dramatically increase the chemical complexity and analytical challenge of characterising MPs and MP-derived organics.

This project addresses the important question of which emerging chemical contaminants from microplastic (MP) degradation are priority targets for future marine surveillance and compliance monitoring of coastal waters. Successful outcomes will include the identification of persistent chemical additives in MP-leachate, that do not degrade and pose a toxic threat to marine ecosystems.

Technical Summary: MP degradation results in the leaching of additives not chemically bound to the polymer matrix, which dramatically increases the chemical complexity and analytical challenge of characterising MPs and MP-derived organics. Consequently, the degradation mechanisms and ecotoxicological effects of degraded MPs and MP-leachates remain poorly understood, with no legislative instruments/policies that provide guidelines for environmental assessments.

The aim of this studentship is to develop a novel multimodal approach, employing a combination of state-of-the-art analytical technologies to conduct a comprehensive compositional analysis of environmental MPs and complex mixture of potentially toxic degradation products. By using a non-targeted approach, the data can also be retrospectively 'mined' for chemical groups of interest identified by stakeholders and other marine research teams.

Recently developed standardised ecotoxicological tests will be used to assess the biological risk of the degraded MP and MP-leachate, alongside the use of the latest chemometric methods to identify a list of priority pollutants released during leaching and degradation of MPs in the marine environment.