Impacts: Microfibre, the less known evil

Hello all!

I have spoken extensively about microplastics in my previous post, and how they may potentially impact human health. However, plastic bags and their fragmentation are only secondary sources of microplastics. Microplastics in the oceans may result directly from primary sources, and the major sources include our familiar microplastic-sized fibre from textiles and microbeads from cosmetics.

Microfibre

Microplastic contamination along the South African beach coastlines has been cited to hail largely (80-90%) from the synthetic plastic fibres that are released during a machine wash cycle. These small plastic fibres are able to pass through preliminary sewage treatment screens (>1.5mm) and are not readily decomposed by bacteria, Eventually, they end up in aquatic environments where they form a substantial volume of microplastic pollution. Based on the results seen in Figure 11, a washing load of polyester-cotton blend, polyester and acrylic clothing release 140k, 500k and 730k of fibre respectively when rounded off to the nearest 2 significant figures. 

Figure 11. Diagram to show the original garments, their typical fibres, the mean fibre dimensions and estimated fibre released per wash cycle (assume a wash load of 6kg).

In another study done by popular apparel company Patagonia in partnership with academics, it was found that an average of 1.2g of microfibers are released from the washing machine when synthetic fleece jackets are washed. Up to 40% of these microfibres make their way into water bodies, depending on the quality of the local sewage treatment. By estimating the volume of plastic microfibre in sewage effluents, it was estimated that the sewage affluents of a population of 100k people would produce approximately 1kg of fibres a day, with more of this produced during winter due to greater washing machine usage (700% greater) from the usage of more clothes.

Microbeads

In the last few years, there has been increasing potential for microplastic pollution through the use of cosmetic products. Microplastics have increasing replaced natural exfoliating materials, such as oatmeal or apricot husk, in facial cleansers, toothpastes and shower gels (see Figure 12). They are often being marketed to consumers in forms such as "micro-beads", "microbead formula" or "micro exfoliates". These plastic microbeads are mostly made of PE (93%), are present in sizes at most up to 1mm, and after usage they similarly travel through wastewater systems for their eventual discharge into oceans due to the inability to degrade naturally.

Figure 12. Exfoliating scrubs in the market (picture source). Find them familiar? Me too.

The average consumer now has a microplastic-containing product in their home and uses it at least on a weekly basis. A case study based in Europe estimated that 680 tonnes of microplastic beads are used and disposed of by the United Kingdom, regionally 4130 tonnes are used in EU countries plus Norway and Switzerland. In the worst case scenario, the relative contributions of microplastic beads to marine litter may constitute up to 11%, although the contribution to the North Sea environment from cosmetic products in 2012 was likely between only 0.1-1.5%.

Thoughts

Microplastic pollution is on a worsening trajectory, as the increases in human population encourage a greater use of cosmetic products and an increase in synthetic textile production. Textile washings are important as part of daily domestic activities, regardless of social and cultural backgrounds; the application of facial scrub exfoliants is also estimated to be used by around 1.1 million women in the UK with daily application. Our plastic behaviour has been very much normalised, with our lifestyle habits damaging the oceans in ways we do not know.

Overall, I have covered the bulk of land-based sources which make up of 80% of plastic debris in the marine environment, namely beach litter (eg. plastic bags), material discarded in landfills, textile fibres from washings and synthetic components of personal care products. Notably, microplastics are extremely difficult to remove from water bodies due to their small size and ubiquitousness. Therefore, the best way to reduce plastic pollution is to minimise it at its source, and after reading week I will broadly cover the legislations and alternatives to plastic waste and packaging.

See you next week!