Textile microplastics: causes and cures – improving our understanding of the drivers of fibre loss during washing (PhD Project)

Freshwater’s macro microplastic problem

Like in the oceans, the bulk of the pollution in rivers and lakes is not in the form of plastic bottles and other large pieces, but tiny pieces called microplastics that would be hard to spot. “Three quarters of what we take out of the Great Lakes are less than a millimeter in size,” she says. “It’s basically the size of a period of a sentence.” These plastics are concerning to scientists because they are being ingested by a variety of aquatic organisms. (…) (pbs.org, 11/05/2017)

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Synthetic fibers as microplastics in the marine environment: A review from textile perspective with a focus on domestic washings

The ubiquity of plastic materials in the environment has been, for long, a matter of discussion. Smaller particles, named microplastics (< 5 mm), gained attention more recently and are now the focus of many studies, especially for their particularities regarding sources, characteristics and effects (e.g., surface-area-to-volume ratio which can increase their potential to transport toxic substances). Fibers from textile materials are a subgroup of microplastics and can be originated from domestic washings, as machine filters and wastewater treatment plants (WWTPs) are not specifically designed to retain them. Once in the environment, fibers can reach concentrations up to thousands of particles per cubic meter, being available to be ingested by a broad range of species. In this scenario, this review adds and details the textile perspective to the microplastics exploring nomenclature, characteristics and factors influencing emission, but also evidencing gaps in knowledge needed to overcome this issue. Preliminarily, general information about marine litter and plastics, followed by specific aspects regarding textile fibers as microplastics, were introduced. Then fiber sources to microplastic pollution were discussed, mainly focusing on domestic washings that pass through WWTPs. Studies that reveal domestic washing as microplastic sources are scarce and there is a considerable lack of standardization in methods as well as incorporation of textile aspects in experimental design. Knowledge gaps include laundry parameters (e.g., water temperature, use of chemicals) and textile articles characteristics (e.g., yarn type, fabric structure) orchestrated by consumers’ choice. The lack of information on the coverage and efficiency of sewage treatment systems to remove textile fibers also prevent a global understanding of such sources. The search of alternatives and applicable solutions should come from an integrated, synergic and global perspective, of both environmental and textile area, which still need to be fostered.

Flavia Salvador Cesa, Alexander Turra, Julia Baruque-Ramos, Science of The Total Environment, Volume 598, 15 November 2017, Pages 1116–1129

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Degradation of common polymer ropes in a sublittoral marine environment

Contamination by microplastic particles and fibres has been observed in sediment and animals sampled from the Firth of Clyde, West Scotland. In addition to microplastics released during clothes washing, a probable source is polymer ropes in abandoned, lost and discarded fishing and recreational sailing gear. The fragmentation of polypropylene, polyethylene, and nylon exposed to benthic conditions at 10 m depth over 12 months was monitored using changes in weight and tensile properties. Water temperature and light levels were continuously monitored. The degree of biofouling was measured using chlorophyll a, the weight of attached macroalgae, and colonising fauna. Results indicate microplastic fibres and particles may be formed in benthic environments despite reduced photodegradation. Polypropylene, Nylon, and polyethylene lost an average of 0.39%, 1.02%, and 0.45% of their mass per month respectively. Microscope images of the rope surface revealed notable surface roughening believed to be caused by abrasion by substrate and the action of fouling organisms.

Natalie A. Welden, Phillip R. Cowie, Marine Pollution Bulletin, Volume 118, Issues 1–2, 15 May 2017, Pages 248–253

The article

Release of synthetic microplastic plastic fibres from domestic washing machines: Effects of fabric type and washing conditions

Washing clothes made from synthetic materials has been identified as a potentially important source of microscopic fibres to the environment. This study examined the release of fibres from polyester, polyester-cotton blend and acrylic fabrics. These fabrics were laundered under various conditions of temperature, detergent and conditioner. Fibres from waste effluent were examined and the mass, abundance and fibre size compared between treatments. Average fibre size ranged between 11.9 and 17.7 μm in diameter, and 5.0 and 7.8 mm in length. Polyester-cotton fabric consistently shed significantly fewer fibres than either polyester or acrylic. However, fibre release varied according to wash treatment with various complex interactions. We estimate over 700,000 fibres could be released from an average 6 kg wash load of acrylic fabric. As fibres have been reported in effluent from sewage treatment plants, our data indicates fibres released by washing of clothing could be an important source of microplastics to aquatic habitats.

Imogen E. Napper, Richard C. Thompson, Marine Pollution Bulletin, Volume 112, Issues 1–2, 15 November 2016, Pages 39–45

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Microfiber Masses Recovered From Conventional Machine Washing of New or Aged Garments

Synthetic textiles can shed numerous microfibers during conventional washing, but evaluating environmental consequences as well as source-control strategies requires understanding mass releases. Polyester apparel accounts for a large proportion of the polyester market, and synthetic jackets represent the broadest range in apparel construction, allowing for potential changes in manufacturing as a mitigation measure to reduce microfiber release during laundering. Here, detergent-free washing experiments were conducted and replicated in both front- and top-load conventional home machines for five new and mechanically-aged jackets or sweaters: four from one name-brand clothing manufacturer (three majority polyester fleece, and one nylon shell with non-woven polyester insulation) and one off-brand (100% polyester fleece). Wash water was filtered to recover two size fractions (>333 μm and between 20 and 333 μm); filters were then imaged and microfiber masses were calculated. Across all treatments, the recovered microfiber mass per garment ranged from approximately 0 to 2 grams, or exceeding 0.3% of the unwashed garment mass. Microfiber masses from top-load machines were approximately 7 times those from front-load machines; garments mechanically aged via 24-hour continuous wash had increased mass release under the same wash protocol as new garments. When comparing to published wastewater treatment plant influent characterization and microfiber removal studies, washing synthetic jackets or sweaters as per this study would account for most microfibers entering the environment.

Niko Lenz Hartline, Nicholas J. Bruce, Stephanie N. Karba, Elizabeth O Ruff, Shreya U Sonar, and Patricia A. Holden, Environ. Sci. Technol., 2016, 50 (21), pp 11532–11538

Emissions of microplastic fibers from microfiber fleece during domestic washing

Microplastics are found in marine and freshwater environments; however, their specific sources are not yet well understood. Understanding sources will be of key importance in efforts to reduce emissions into the environment. We examined the emissions of microfibers from domestic washing of a new microfiber polyester fleece textile. Analyzing released fibers collected with a 200 μm filter during 10 mild, successive washing cycles showed that emission initially decreased and then stabilized at approx. 0.0012 wt%. This value is our estimation for the long-term release of fibers during each washing. Use of detergent and softener did not significantly influence emission. Release of fibers during tumble drying was approx. 3.5 times higher than during washing.

U. Pirc, M. Vidmar, A. Mozer, A. Kržan, Environmental Science and Pollution Research, November 2016, Volume 23, Issue 21, pp 22206–22211

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