Microplastic are plastics that are < 5mm and is a contaminant of emerging concern in the aquatic environment. They are produced to be of a microscopic size or are created through the fragmentation of larger plastic material due to degradation. Microplastic has been found to be ubiquitous in the marine and freshwater environment with shoreline and deep sea sediment, oceans, rivers and lakes throughout the world observed to be polluted by microplastic. Wild populations of aquatic biota with various feeding behaviour have been observed to ingest microplastic. Exposure studies have also demonstrated the harmful effects of microplastic on a range of aquatic organisms. In this thesis, various aspects of microplastic pollution were investigated, from the sources of microplastic in the environment, to the destination of the microplastic once it enters the environment as well as the potential effects of microplastic on exposed organisms. The contribution a wastewater treatment works (WwTW) is making to microplastic pollution in the environment was estimated and the extraction efficiency of microplastic within the treatment process was determined. This study identified the key parts of microplastic removal in the treatment process. Aquaculture was also investigated as source of microplastic in the environment by comparing synthetic rope and netting used in the industry with microplastic extracted from cultured fish and wild shellfish. The ingestion of microplastic by a variety of fish species sampled from Scottish marine waters were investigated finding considerably higher ingestion rates in demersal flatfish sampled from coastal waters then species sampled further offshore in much deeper waters. The effects of microplastic were investigate by developing a novel bioassay to measure ecologically relevant endpoints such as feeding and reproduction as well as morphology in Hydra attenuata exposed to microplastic. H. attenuata feeding was found to decrease as microplastic concentration increased. This work shows that microplastic is ubiquitous throughout the aquatic environment and can potentially effect exposed organisms.
|Qualification||Doctor of Philosophy|
|Award date||1 Jun 2017|
|Publication status||Published - 2017|