A domestic washing machine probably releases more than 700,000 microscopic fibers each time it is used. Many of these likely reach the environment as they simply pass through sewage treatment plants.
In a study done at Plymouth University, the size, mass and quantity of fibers present in waste effluent was examined after washing of synthetic fabrics at commonly used temperatures of 30˚C and 40˚C.
Previous work at Plymouth University found that a major source of microscopic fibers within the aquatic environment is the washing of clothes. The new study confirmed these findings when it found that hundreds of thousands of tiny synthetic particles could be released in each wash.
The research was led by PhD student Imogen Napper together with Professor Richard Thompson, and published in Marine Pollution Bulletin. Thompson is a leading international expert on micro plastics and marine rubble and has worked in the field for more than 2 decades.
The researchers noted that the focus of their research was to provide quantitative data on the relevant importance of micro fibers from washing textiles as a source of micro plastic in the environment. They also looked at other factors that might influence the discharge of micro plastic into the environment. Over the next few decades, it is expected that the amount of micro plastic in the environment will increase sharply, and there are fears about the potential for it to have harmful effects if ingested.
A series of acrylic, polyester-cotton and polyester items were washed at 30˚C and 40˚C for the study. Various combinations of fabric conditioner and detergent were used. Extracting fibers from the waste effluent, these were examined using an electron microscope to determine the typical size and any differences in mass and quantity among treatments.
It was found that washing an average load of 6 kg could release an estimated 728,789 fibers from acrylic, 137,951 fibers from polyester-cotton blend fabric and 496,030 from polyester. Regardless of the different treatments, the polyester-cotton blend was found to shed fewer fibers than either acrylic or polyester consistently. The addition of conditioners or bio-detergents did however tend to increase the number of fibers released.
Thompson, the leader of the International Marine Litter Research Unit at Plymouth University, recently provided both oral and written evidence to the micro plastics inquiry held by the House of Commons Environmental Audit Committee. This eventually led to recommendations for a ban on the use of microbeads in cosmetics.
He did however note that in this case, unlike the recently announced ban on microbeads, these new research results are not likely to trigger a similar ban.
In the microbead case, there was no clear societal benefit from incorporating micro plastic particles into the cosmetics. This, coupled with concerns about environmental impacts, was taken into account before the guiding policy intervention was proposed.
The societal benefits of textiles are however without question. Any voluntary or policy intervention would therefore likely to be directed toward reducing emissions through either filtration of effluent, or changes in textile design, or both.
Study has been published in the journal Marine Pollution Bulletin.