Does microplastic pollution pose a risk to marine life and food security?

Walkinshaw, Chris (2022) Does microplastic pollution pose a risk to marine life and food security? Doctoral thesis, University of East Anglia.

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Microplastics are a persistent and pervasive pollutant, ubiquitous in marine environments worldwide. Owing to their size and prevalence, microplastics have been demonstrated to be ingested by marine organisms throughout the food chain. However, the risks that microplastics pose to commercially exploited marine organisms are poorly elucidated. There is a lack of information pertaining to the inputs of microplastic into farmed marine species, the effect of environmentally relevant concentrations of microplastics on commercially important marine organisms, and ultimately whether microplastics may pose a risk to food security. In this thesis, I combine literature analysis with novel quantitative data through a suite of microplastic identification techniques and exposure experiments to explore these gaps in our current knowledge. My data demonstrates that while commercially-important organisms throughout the food chain ingest microplastics, lower trophic level organisms contain the highest body burdens of microplastics and there is little evidence that microplastics biomagnify. I identify that prolonged exposure to environmentally realistic concentrations of microplastic fibres results in lower growth rates in the commercially-exploited marine bivalve Mytilus edulis. I highlight a novel pathway for the contamination of farmed fish with microplastics via contaminated aquaculture feed. Finally, I performed a methods comparison of commonly used microplastic identification techniques to reveal micro-FTIR and py-GCMS are the most effective means for characterizing microplastics in complex samples, but resultant data are not readily comparable. My thesis draws attention to the prevalence of semi-synthetic and cotton microfibres in marine samples, and how their environmental risk is often ignored. This research contributes to our knowledge of how microplastics and other anthropogenic particles can contaminate aquaculture feed and adversely affect lower trophic level organisms, posing a risk to marine food security, and guides researchers as to the best techniques to use when analysing complex organic samples.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: Nicola Veasy
Date Deposited: 07 Jun 2023 10:28
Last Modified: 31 Jan 2024 01:38


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