Capturing marine microplastics with mussel power

A 1m2 patch of Mytilus edulis (the common or blue mussel) has the ability to filter 150,000 litres of water per day. They are natural biofilters and evidenced to ingest and defecate microplastics. This phenomenal ability could be harnessed to capture and remove microplastics from the environment, potentially providing a solution to reduce this contaminant in our waterways. The feasibility of using Mytilus to filter and sequester microplastics was previously established in the laboratory, where 5kg of mussels filtered 200,000 microplastics per hour. This was followed by testing a prototype in the environment, where mussels in cages filtered and egested 4.5 times more microplastics than control cages. The next stage was to scale up the use of Mytilus and apply the system to relevant environmental locations. Here we report on Phase 2 of the project, where bespoke cage systems were manufactured to hold 50 kg of mussels, collect their faeces and facilitate sample retrieval through pumping material to the surface. Two cage systems (with and without mussels) were deployed at each of 4 selected sites, which consisted of a presumed clean site in the Salcombe estuary and 3 sites on the River Plym, positioned at increasing distance downstream from a sewer storm overflow outlet pipe and bridge carrying traffic to/from the city. Cages at site 2 were kept in-situ for 77 days and sampled bi-weekly, while the 3 other sites were sampled on day 7 only. Subsamples were incubated in 10 Also see: https://micro2024.sciencesconf.org/559502/document