Three years ago, Dr. Mark Browne of University College Dublin led a study that investigated the sources and sinks of microplastic, i.e. tiny pieces of plastic debris measuring less than a millimeter in length that have accumulated in marine habitats throughout the oceans. Previously, the primary cause of microplastic was thought to be the degradation, over time, of larger plastic debris, but the results of Browne’s study suggest that a significant proportion of microplastic particles may come from another, more insidious source. The 2011 research paper published by Browne and his co-authors (who represent academic institutions in Australia, the United Kingdom and Canada) proposed that washing synthetic clothes could be a direct cause of microplastic pollution. Scientists collected sediment samples from six continents and 18 sites, including beaches in Australia, Japan, Oman, South Africa, the Philippines, the U.K. and the U.S. They tested the samples for microplastic fibers, and the results found that every single sample was contaminated with the tiny, plastic particles. Although these particles are small, their impact should not be underestimated, as they accounted for 85 percent of the manmade waste found on the sampled beaches.
Some of the samples collected were more contaminated than others; for example, one from Australia contained only 8 fibers per liter of sediment, while a Portuguese testing site yielded 124 fibers per liter. Browne and his colleagues soon saw a pattern emerging from the test results, in that the amount of microplastic in a sample corresponded directly to the level of development in the area from which it was taken. The most densely populated areas produced the samples with the most plastic fibers, while remote areas were minimally contaminated. Based on this correlation, the research team concluded that the microplastic was coming from a human source and began investigating its origins. The first step was to find out what kind of plastics the particles were comprised of; testing found that the major culprits were polyester, acrylic and nylon. These materials are all used to make synthetic clothing, and the proportions of the fibers used in synthetic clothing directly reflected the proportions of the same polymers found at each of the testing sites. As a result of these findings, the team developed the theory that the microplastics were coming from the wastewater of washing machines, in which small fibers and pieces of clothing lint had accumulated. The wastewater would then contribute to sewerage discharges, which in turn end up in the ocean.
In order to find out whether this theory was correct, the team took samples from the effluent of two sewage treatment plants in Sydney, Australia, and tested them for microplastic. They found that the plastic particles in the effluent matched the synthetic polymers found at the 18 global testing sites both in type and proportion, leading them to the conclude that their theory about washing machine wastewater as a source of the contamination was correct. To ascertain the impact of this source, the scientists tested just how many plastic fibers are lost when a piece of synthetic clothing is washed. By sampling wastewater from domestic washing machines containing synthetic clothes and blankets, they found that a single item shed as many as 1,900 fibers per wash, all of which could potentially end up in the ocean. The global population density of humans has increased by 250 percent in the last 50 years, and in that time the use of synthetic materials in clothing, as well as the number of people who have access to washing machines, has also grown. Therefore, the potential impact of washing-machine wastewater as a source of marine microplastic pollution both now and in the future is huge.
The consequences of this kind of pollution are uncertain, although it has been proven that marine organisms do ingest microplastic and are therefore vulnerable to the transfer of pollutants, monomers and plastic additives. According to studies conducted by Browne, animals that consumed the fibers showed evidence of plastic accumulation in their cells; currently, the extent of the injury is unknown. What is certain, however, is that potential ramifications will be felt throughout the food chain, as microplastic sinks to the seafloor where it is taken up by benthic species including clams, mussels and small fish. When larger animals prey on these smaller animals, the plastic is transferred and accumulates exponentially as it ascends the food chain. Humans could also be at risk when microplastic pollutants contaminate food species, while the break down of plastic when exposed to low temperatures could also see the leakage of chemicals into the water column.
While more research is needed to define the precise nature of the microplastic threat, common sense tells us that this threat is very real. Browne set up a program in 2013 called Benign By Design, which aims to help governmental and industrial agencies find a solution to the migration of microplastic fibers into the marine ecosystem, and ultimately such research could lead to a solution, whether the development of textiles that shed fewer fibers or washing machines that capture and prevent the fibers from entering the sewerage system. However, the research is costly, and so far Browne’s initiative has received minimal support from leading clothing and washing machine manufacturers. Despite approaching several prominent companies, including Patagonia and Polartec on the clothing front and Siemens and LG on the appliance front, Browne has received a positive response from only one brand, clothing manufacturer Eileen Fisher. The grant given to Browne by Eileen Fisher will go some way towards supporting his research efforts, but the collaboration of major synthetic clothing retailers and washing machine manufacturers is critical if the this issue is to be addressed. The rest of the companies that Browne has approached have either turned him down or ignored his request.
All is not lost, however, and help may yet be forthcoming from a former engine airplane mechanic named Blair Jollimore. Canadian Jollimore is something of a self-styled inventor and entrepreneur, and he’s created a washing machine filter that he believes may prevent microplastic fibers from entering the water system. Currently he’s improving the filter so that it doesn’t negatively affect washing machine’s efficiency. Once perfected, he intends to pitch it to appliance manufacturers as a solution to the synthetic microfiber problem. Perhaps entrepreneurial solutions like these will help solve this little-recognized environmental issue, but at the very least, they will attract attention to it, hopefully inspiring bigger corporations to get behind Browne and his Benign By Design initiative.