Thesis Defense: Microplastics in blue mussels (Mytilus edulis) from the Westfjords region in Iceland

In the coming weeks, UW master's students will defend their theses. The subjects are varied and the students are from both master's programs, Coastal Marine Management and Coastal Communities and Regional Development. The defenses are accessible to everyone through zoom links but they are also open to the public, at the University Centre of the Westfjords in Ísafjörður.

Wednesday at 14:00 May 8th

Student: Robyn de Bruijn
Thesis title: Microplastics in blue mussels (Mytilus edulis) from the Westfjords region in Iceland
Program: Coastal Marine Management
Abstract: Microplastic pollution poses a significant threat to marine ecosystems, yet its
distribution and characteristics in remote coastal regions, such as the Westfjords
of Iceland, remain poorly understood. In this study, blue mussels (Mytilus edulis)
were collected from three distinct locations within the Westfjords, two of which
were in the rural town of Ísafjörður. The first was connected to open water,
while the other was situated in the ‘Pollurinn’, protected by the sand spit
Ísafjörður is built on. The third location was in a fjord further away with limited
human activity, except for a single nearby farm. The study looked at the effect of
currents on the presence of microplastics, as well as the effect of urbanization.
After collection, mussel samples underwent chemical digestion followed by
filtering through a 2.7μm glass fiber filter and plastic identification using the 'hot
needle test' to detect the presence of microplastics. This test, requiring minimal
equipment, involved applying heat to suspected particles to observe melting
behavior. The study compared the types, sizes, shapes, and colors of
microplastics found across the sampled locations.
Results showed plastics were present at every location, in forms of ‘beads’,
‘fragments’, and ‘fibers’. Out of the 60 mussels studied, 68.3% contained at least
one microplastic. The shape frequency did not differ significantly between
locations. The microplastics found were between 0.3 and 4.2 mm in size, with
the plastics from Northern Beach and Skötufjörður having significantly different
mean sizes. The colors black and dark blue were most commonly found.
Urbanization was found to have limited effect on the microplastic presence in
the mussels. While some more microplastics were found in mussels from the
urban area, these did no differ in color and shape. There was limited effect on
the size. Mussels from the location with better water flow contained more and
larger microplastics.
This research showed that hot needle testing can identify microplastics,
although not without error margin. Further tests like Raman spectrometry are
needed to confidently identify all plastic particles, but in absence of machines
like this, hot needle testing can give a good indication of microplastic presence.

Zoom link: https://eu01web.zoom.us/j/62652379881

Defense schedule for this defense season: