Plastics are synthetic materials made from polymers (very long-chain molecules) originally derived from fossil fuels. They are designed to be chemically stable and inert – so the same properties which make them incredibly useful also mean they do not bio-degrade in the natural environment. Rather, they just physically break down into smaller and smaller pieces. Microplastic debris (particles smaller than 5mm) is a persistent and widespread issue in marine ecosystems, and a growing part of the marine food chain.

In this part of the world, Lisa Blair’s recent (2022) record-breaking sail around Antarctica also
produced the most comprehensive microplastics dataset for the region. In partnership with marine science organisations, this brilliant example of “citizen science” resulted in the first near-continuous microplastics survey in Southern Ocean waters. A total of 178 seawater samples were continuously collected with 83 processed and analysed.

The data confirmed that, like other oceans, the Southern Ocean is broadly contaminated with microplastics – regardless of proximity to land sources. Polyethylene-based polymers were the most predominant (46%), followed by polyester-based items (24%). Various other polymers such as polypropylene, nylon, pvc, polystyrene and polyurethane rubber were also present.

Virtually all the microplastics found were secondary items, i.e. originating from the breakdown of larger plastic debris. Interestingly, fibres (64.8%) were more abundant than fragments. The link is with laundry where every 2.5kg load typically produces over 300 microplastic fibres which are not retained in the machine.

Where does it come from? Data from the USA suggests microplastics derive mostly (in decreasing order) from synthetic textiles (35%), tyres, urban dust and run off, road markings, marine coatings (4%), personal products, plastic pellets (<1%) and many other sources.

Suggested actions to minimise your contribution

• Reducing microplastic fibres by buying clothing from natural materials and installing a filter on your washing machine.
• Reduce, refill, repurpose.
  • plastic containers were designed to last forever!
• According to Sailors For The Sea, eliminating single-use plastic at the source is the most impactful thing we can do.
  • we all make decisions as consumers and may also have opportunities to support policies that will reduce plastic production
• Given the amount of vehicle or road-derived microplastic debris, driving less would have a positive impact.
• And of course, be mindful of plastic pollution in the streets and waterways – most city drains flow untreated direct to the sea.

Sources

https://lisablairsailstheworld.com/
https://sailorsforthesea.org/blog/where-does-plastic-come-from/
https://www.sciencedirect.com/science/article/pii/S2666016420300086