Occurrence, characterisation and variations of microplastics and cellulose fibres in the Scottish Atlantic coastal marine environment

Over the past decade, microplastics have proven to be globally ubiquitous and<br/>widespread, and as a result are considered one of the major threats for the<br/>environment and potentially human health. In the marine coastal environment,<br/>microplastics have been widely studied. However, specific information about their<br/>dynamics, behaviour and fluxes through different environmental compartments are<br/>missing. Numerous uncertainties regarding microplastic pollution in the Scottish<br/>marine environment persist as few studies have investigated the passage of<br/>microplastics through the ecosystem by looking at mussels, seawater and sediment.<br/>To contribute to the knowledge gaps regarding composition, distribution and<br/>spatial/temporal variability in microplastics, it is necessary to consider several<br/>environmental compartments covering a large spatial area. A tool-kit was<br/>specifically designed to be used by citizen scientists to collect microplastics from<br/>seawater, beach sediments and wild mussels covering ~400 km of the North and<br/>West Scottish coastline allowing for microplastic composition and concentrations at<br/>both spatial and temporal scales to be investigated. The results of this thesis<br/>highlight that microplastics were found at every sampling site and in every<br/>compartment studied, with concentrations relatively low in sediment being 60 ± 10<br/>particles/kg d.w., whilst in water they were 1220 ± 170 particles/m-3 and in mussels<br/>were 0.60 ± 0.12 particles/g wwt, which is similar to what has been seen on mainland<br/>European coastlines. Microplastic characteristics and concentrations varied<br/>between locations for all three environmental compartments ranging from 20 ± 10<br/>to 120 ± 40 particles/kg d.w. for sediment, 700 ± 260 to 1800 ± 460 particles/m-3 for<br/>seawater and 0.19 ± 0.05 to 1.38 ± 0.64 particles/g wwt for mussels, that were under<br/>the influence of diverse factors (e.g. tide, wave, topography of site, proximity to river<br/>mouth or anthropogenic activities and urbanised areas). Potential sources and<br/>pathways were highlighted such as clothing/textile industry, tourism, sailing/fishing,<br/>wastewater and towns for the dominant ones, but paints and road dust were also<br/>recorded, influencing the composition of microplastics (i.e. polymer type, shape and<br/>size) residing in the three compartments. Temporal variations of microplastic<br/>composition and concentrations were noted for seawater and mussels (usually<br/>winter &gt; summer) fluctuating with seasons suggesting a combined influence of biotic<br/>and abiotic factors (rainfall, wind, tourism). Investigations into semi-synthetic and<br/>natural fibres found that cellulose fibres were mostly natural even though semi-synthetic fibres were also present. The<br/>cellulose fibres dominated the particles found in mussels (60%), seawater (53%)<br/>and in the sediment (63%). This work demonstrates that microplastics are<br/>widespread, prevalent and dynamic pollutants, moving in a complex coastal<br/>environment and that further studies are required to elucidate whether cellulose<br/>fibres present the same problems that are associated with microplastics.

Name dc:type.qualificationname

Doctor of Philosophy (awarded by UHI)

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

University of the Highlands and Islands

Year dc:date.issued

2022

Author dc:creator

• Paradinas, Lola

Advisors dc:contributor.advisor

• Narayanaswamy, Bhavani
• James, Neil
• Dale, Andrew

Language dc:language

eng

Identifier

oai:pure.atira.dk:studenttheses/cba793a3-eab6-4dcd-a719-99a2c16d65de

OAI identifier oai:identifier

oai:pure.atira.dk:studenttheses/cba793a3-eab6-4dcd-a719-99a2c16d65de