Laundering and textile parameters influence fibers release in household washings☆
Graphical abstract
Introduction
Just a few decades after synthetic polymers mass production begun, the first debris were reported in marine habitats (Buchanan, 1971; Carpenter and Smith, 1972). Corresponding to the middle of the 20th century, this period marked the start of an incommensurable plastic pollution era, which currently is represented by the ubiquity of this material in the natural environment (Kosuth et al., 2018; Zalasiewicz et al., 2016) and more recently, by its presence even in food and water destined for human consumption (Kosuth et al., 2018; Schymanski et al., 2018).
From all sizes of plastic, smaller pieces, named microplastics (GESAMP, 2019), gained crescent attention and are currently targeted by several studies due to the potential damage they can cause when liberated in the environment (SAPEA, 2019; UNEP, 2016). Among the types of microplastic accumulated, synthetic fibers are frequently pointed as predominant (Carr, 2017; Verschoor et al., 2014; Wright et al., 2013), common in both shoreline and offshore sediments (Zalasiewicz et al., 2016). Although filiform microplastics have long been encountered in the marine environment (Buchanan, 1971), it was only in the beginning of 21st century that synthetic clothes' washing was considered a potential source (Browne et al., 2011) and more recently, for particular countries, a dominant one (Boucher and Friot, 2017).
Microplastics, in general, are defined as particles or fragments <5 mm (GESAMP, 2019), composed of synthetic polymers and formed by long organic molecular chains (UNEP, 2016). As manmade materials, they were originally developed not to completely decompose and currently there are only a few species capable of mineralizing them (Andrady, 2011; GESAMP, 2015). Consequently, they accumulate from terrestrial (Wiewel and Lamoree, 2016) to aquatic habitats, including soil (Zubris and Richards, 2005), rivers (Dris et al., 2018), lakes (Eriksen et al., 2013) and oceans (Eriksen et al., 2014; Zalasiewicz et al., 2016).
The issue related to the widespread presence of plastics, especially in the marine environment (Sillanpää and Sainio, 2017), deals with ecologic and socioeconomic impacts, which include, primarily, their interaction with biota and the potential effects on human health (GESAMP, 2016, 2019; SAPEA, 2019). This happens, for example, when microplastics are taken up through ventilation or are ingested directly or indirectly by organisms (GESAMP, 2016). Though the main body of research deals with consequences related to the lower levels of biological organization (e.g. molecules, cells and organisms), it is recognized that this interaction can cause responses like reduced health, feeding, growth and survival (GESAMP, 2016; Nobre et al., 2015; Rochman et al., 2016). Additionally, the presence or sorption of toxic substances in plastics (e.g. bisphenol A, persistent organic pollutants and metals) can cause bioaccumulation in organisms, potentially reaching humans (Mathalon and Hill, 2014).
Specifically regarding toxic chemicals, authors such as Sillanpää and Sainio (2017) and Dris et al. (2018), argue that materials of non-synthetic origin should also be considered as transport pathways of harmful components to the environment. In the context of textile fibers, that includes manmade artificial (e.g. viscose) and natural (e.g. cotton) ones that were already encountered in the aquatic environment and ingested by the biota (Dris et al., 2018; Lusher et al., 2014; Remy et al., 2015). In fact, all types of fibers can contain harmful substances like dyestuff and additives with the potential to cause ecologic and socioeconomic impacts (Cesa et al., 2017; Dris et al., 2018; Zhao et al., 2016).
Linking toxic impacts from textiles with current values of production, just in 2016, 100 million tonnes of fibers were consumed (Oerlikon, 2017). From these, the vast majority was destined to apparel (Angel, 2016) and around 70% accounted to manmade materials, i.e. artificial and synthetic (Dris et al., 2018). Indeed, since the development of viscose, in the 19th century, manmade fibers produced a turning point in human relationship with textiles. We went from an in natura period to a broad spectrum of options that, with higher controlled properties, enabled more versatility and new applications (Mogahzy, 2009; Needles, 1986). If in the middle of the 20th century, synthetic fibers, which are the only group to be considered microplastics (Cesa et al., 2017), represented a consumption of around 2 million tonnes; in 2010 that number turned to >40 million tonnes or around 60% of all textiles destined to apparel (FAO-ICAC, 2013). In the same year, cotton represented almost 33% and all other cellulosic fibers, about 7% (Essel et al., 2015; FAO-ICAC, 2013).
With projections of growth in textile consumption for the near future, acquisition and use of household washing machines are also expected to increase (Dris et al., 2018; Laitala et al., 2011; Pakula and Stamminger, 2015). Nevertheless, it is considered that there are already >840 million units of this equipment with different models and commands worldwide (Barthel and Götz, 2013; Pakula and Stamminger, 2015). Regarding washing effluents, <30% of global population have access to wastewater treatment plants (WWTPs), with worst numbers in developing economies (GESAMP, 2016), which in turn buy a larger proportion of synthetic textiles (68.0%) when compared to the developed ones (48.2%) (Boucher and Friot, 2017). In fact, even when effluents are directed to WWTPs, microplastics are not completely removed (Browne et al., 2011), with worst retentions in simpler treatments (Talvitie et al., 2015). That is the case of submarine outfalls, for example, which are frequently employed worldwide (Powley et al., 2016; Wang et al., 2016) and deliver large concentrations of fibers into the marine environment (Rochman et al., 2015). Additionally, even what is retained in WWTP can be released directly to terrestrial environments, used as sludge products (Zubris and Richards, 2005).
In this way, since Browne et al. (2011) revealed the issue of domestic washings generating microplastics, there was a crescent interest related to the topic and although some advances were made, many gaps remain unsolved. These refer specially to understanding how chemical (e.g. detergent) and mechanical (e.g. number of washings, type of washing machine) actions reflect upon textiles and affect fibers shedding (Almroth et al., 2018; De Falco et al., 2017; Mac Namara et al., 2012).
Regarding washing parameters, although previous research could not evaluate detergent use, due to difficulties with filtration (Browne et al., 2011), several authors dedicated to understand this product's influence (Almroth et al., 2018; Åström, 2016; De Falco et al., 2017; Hernandez et al., 2017; Napper and Thompson, 2016; Pirc et al., 2016; Zambrano et al., 2019), with no consensus until the moment. Analogously, although a considerable number of studies performed up to 5 cycles of sequential washes (Folkö, 2005; Kelly et al., 2019; Napper and Thompson, 2016; Sillanpää and Sainio, 2017; Zambrano et al., 2019) only a few executed 10 (De Falco et al., 2019; Pirc et al., 2016), demanding more research to investigate the effect of the number of sequential washes on fibers release. Regarding textile compositions (cotton, acrylic, polyester and polyamide), although natural fibers cannot generate microplastics, cotton also needs to be analyzed because of its importance in the textile industry (Almroth et al., 2018; Browne et al., 2011; FAO-ICAC, 2013; Sillanpää and Sainio, 2017) and its potential to transport toxic substances (Dris et al., 2018). As only a few washing experiment tested it (Sillanpää and Sainio, 2017; Zambrano et al., 2019) more research is necessary. Finally, the majority of domestic washing experiments neglected washing machine real filters and their capacity to retain fibers (Zambrano et al., 2019). This creates not only the need to simulate real conditions faced by consumers, but the consideration of improvements for this type of device.
In this scenario, the present study aims to explore how new combinations of washing and textile parameters may influence fibers release. For that purpose, one factor related to chemical action (detergent) and one to mechanical action (10 sequential washes) were applied to cotton, acrylic, polyester and polyamide. Masses of fibers retained in the filters of the washing machine were also quantified and categorized. The data was analyzed to assess the potential of a set of simple measures to reduce fibers pollution coming from domestic washings.
Section snippets
Textiles
For the experiment, 4 types of garments with different compositions were selected. As they were purchased from the regular market, Fourier Transform Infrared Spectroscopy (FTIR) analyses were used to confirm fiber content and nature of cotton fiber, as natural or mercerized (results presented in Supporting Information, Figs. S1–S4). Mercerization is described by Mogahzy (2009) as treating fiber with a high concentration of caustic soda to swell and reorganize it, changing some original
Results
A summary of results from the gravimetric method is presented in Table 2. Considering all filtrating materials and 10 consecutive cycles, masses of fibers released in washings varied from a minimum of 49.8 mg to a maximum of 307.8 mg. In relative values, quantities released per article in 10 sequential cycles, varied from a minimum of 0.03% (percent mass) to a maximum of 0.20%.
Overall results
Although the gravimetric method results should be examined conservatively, considering similar but not equal methodologies (i.e. garments individually washed, conventional washing machines, relative masses), results from the present study were aligned to previously published ones. In the case of Pirc et al. (2016), for example, polyethylene terephthalate blankets tested for 10 consecutive cycles and filtered in a 200 μm × 200 μm sieve resulted in 0.04% of fibers released for washings WOD and
Conclusions
The current study aimed to quantify fibers emitted during domestic washings, relying on laundry parameters and textile characteristics that affect garments release. Regarding textile characteristics, articles with a more cohesive structure proved to release fewer quantities of fibers, opposed to those with a more open structure. Although other textile features were not considered, these preliminary inferences could help future studies to design developments and establish minimum manufacture
Acknowledgements
Special thanks to Eduardo Barrios, which contributed with insights, related to textile issues. This work was supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazilian Federal Agency for Support and Evaluation of Graduate Education) [grant number 7873981]. AT and HHC received a research grant from CNPq (Proc. 309697/2015-8 and 150316/2018-6, respectively).
References (75)
Microplastics in the marine environment
Mar. Pollut. Bull.
(2011)- et al.
Microplastics' emission: Microfibers'detachment from textile garments
Environmental Pollution
(2019) Pollution by synthetic fibres
Mar. Pollut. Bull.
(1971)- et al.
Synthetic and non-synthetic anthropogenic fibers in a river under the impact of Paris Megacity: sampling methodological aspects and flux estimations
Sci. Total Environ.
(2018) - et al.
Microplastic pollution in the surface of the Laurentian Great lakes
Mar. Pollut. Bull.
(2013) - et al.
Microfibres from apparel and home textiles: prospects for including microplastics in environmental sustainability assessment
Sci. Total Environ.
(2019) - et al.
Microplastic pollution in the Northeast Atlantic ocean: validated and opportunistic sampling
Mar. Pollut. Bull.
(2014) - et al.
Dynamics of textile motion in front-loading domestic washing machine
Chem. Eng. Sci.
(2012) - et al.
Microplastic fibers in the intertidal ecosystem surrounding Halifax Harbor, Nova Scotia
Mar. Pollut. Bull.
(2014) - et al.
Release of synthetic fibres from domestic washing machines: effects of fabric type and washing conditions
Mar. Pollut. Bull.
(2016)
Assessment of microplastic toxicity to embryonic development of the sea urchin Lytechinus variegatus (Echinodermata: Echinoidea)
Mar. Pollut. Bull.
Selection of effective macroalgal species and tracing nitrogen sources on the different part of the Yantai Coast, China, indicated by macroalgal δ15 values
Sci. Total Environ.
Geotextile composition, application and ecotoxicology – a review
J. Hazard Mater.
The physical impacts of microplastics on marine organisms: a review
Environ. Pollut.
Microfiber release from different fabrics during washing
Environ. Pollut.
Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation
Mar. Pollut. Bull.
The geological cycle of plastic and their use as a stratigraphic indicator of the Anthropocene
Anthropocene
Microscopic anthropogenic litter in terrestrial birds from Shanghai, China: not only plastic but also natural fibers
Sci. Total Environ.
Synthetic fibers as an indicator of land application of sludge
Environ. Pollut.
Long wash cycle duration as a potential for saving energy in laundry washing
Energy Effic.
Quantifying shedding of synthetic fibers from textiles; a source of microplastics released into the environment
Environ. Sci. Pollut. Control Ser.
Product Developments in manmade fibres: is cotton able to compete?
Shedding of Synthetic Microfibers from Textiles
The Overall Worldwide Saving Potential from Domestic Washing Machines: with Results Detailed for 10 World Regions
Primary Microplastics in the Oceans: A Global Evaluation of Sources
Ministerio das Cidades. Secretaria Nacional de Saneamento Ambiental – SNSA. Sistema Nacional de Informacoes sobre Saneamento: Diagnostico dos Servicos de Água e Esgotos – 2015
Accumulation of microplastic on shorelines worldwide: sources and sinks
Environ. Sci. Technol.
Plastic on the Sargasso sea surface
Science
Sources and dispersive modes of micro-fibers in the environment
Integr. Environ. Assess. Manag.
Synthetic fibers as microplastics in the marine environment: a review from textile perspective with a focus on domestic washings
Sci. Total Environ.
Evaluation of microplastic release caused by textile washing processes of synthetic fabrics
Environ. Pollut.
The contribution of washing processes of synthetic clothes to microplastic pollution
Sci. Rep.
Brazil Laundry Habits & Attitudes
Plastic Pollution in the world's oceans: more than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea
PLoS One
Source of Microplastics Relevant to Marine Protection in Germany
European Council. Regulation (EU) No 259/2012 of the European Parliament and of the Council of 14 March 2012 amending Regulation (EC) No 648/2004 as regards the use of phosphates and other phosphorous compounds in consumer laundry detergents and consumer automatic dishwasher detergents
Cited by (97)
Investigation on microfiber release from elastane blended fabrics and its environmental significance
2023, Science of the Total EnvironmentImpact of sewing on microfiber release from polyester fabric during laundry
2023, Science of the Total EnvironmentImpact of quantification method on microfiber assessment – A comparative analysis between mass and count based methods
2023, Journal of Environmental ManagementImproving of an easy, effective and low-cost method for isolation of microplastic fibers collected in drying machines filters
2023, Science of the Total Environment
- ☆
This paper has been recommended for acceptance by Lei Wang.