Citizen science experiment targets microplastic pollution in washing machines

Scientist Dominique Claveau recorded all kinds of data in each washing machine she put in between June and November 2021.

By Ground report 30 Sep 2023

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Citizen science experiment targets microplastic pollution in washing machines

Scientist Dominique Claveau recorded all kinds of data in each washing machine she put in between June and November 2021: she recorded washing with cold or hot water, program and duration, type of clothing, detergent, and the number of washes per day.

After about four or five washing machines, she performed a manoeuvre that 30 other households also did. This manoeuvre consisted of emptying and cleaning the microplastic filter that they had installed for a citizen science experiment.

Microplastic pollution source targeted effectively

Claveau, who works as project director at the Polytechnic University in Montreal, comments via videoconference, “We wanted to know how much of that pollution can be saved by stopping it where it occurs, in this case, in the washing machine. Textile fibers are the main source of pollution of rivers and oceans by microplastics."

The International Union for Conservation of Nature (IUCN) states that microfibers from clothing are responsible for 35% of microplastic pollution. Synthetic fabrics release these particles, which are smaller than 5 mm and cannot be seen by the human eye, in large quantities with every wash.

Additionally, vehicle tires with their bearings and cosmetic products also contribute to the release of these microfibers. Consequently, these microfibers can be found everywhere, including rivers and oceans, and are even present inside fish and humans. It is already widely acknowledged that plastic is being consumed by us.

Textile fibers are the main source of pollution of rivers and oceans by microplastics, we wanted to know how much of that pollution can be saved by stopping it where it occurs, in this case, in the washing machine.

Dominique Claveau — Researcher at the Polytechnic University of Montreal (Canada)

Catherine Houbart, environmental activist and director of the conservation organization GRAME, gave the idea for the experiment to academic Dominique Claveau. Houbart discovered, "with great surprise," that the Saint Lawrence River, one of the main rivers in North America and the natural border between the United States and Canada in its first section, is one of the most contaminated by microplastics in the world.

She wanted to address the problem together with citizens, in homes and with real washing, not by spinning a washing machine in a laboratory. After conducting the experiment, she would need the university to analyze the data.

Making invisible visible: 12.8 tons of plastic retained

A Canadian manufacturer sold the filters to the GRAME organization, and the organization searched for volunteers who recorded, like Dominique and Catherine herself, all the details about their washing for six months. Volunteers were instructed to periodically clean the externally installed filters connected to the washing machines and to separate the matter that was discharged from them.

Claveau says, "I used a coffee filter to throw away the excess water at first; I couldn't dispose of it as is in the sink because it also contained microplastics." The volunteers put what the filter caught into small plastic bags with airtight seals, which they froze or dried. Then, they mailed them in two batches to the Polytechnic University of Montreal.

publive-image — Plastic microfiber samples were isolated in the laboratory. Polytechnic University of Montreal

In the laboratory, they first dried and weighed the samples. Next, they cleaned the material and left out natural fabrics such as cotton. “What we obtained was a reflection of how the clothes are made, which does not always coincide with what the label says,” explains the polytechnic researcher. What came out is that 32% of the recovered tissues were plastic. “With the data in hand, we took out the calculator,” as explained Mohammed Abourich, author of the report after the experiment.

Filters capture microplastics, reduce pollution

With each wash, the filter traps 87% of the microplastics released, and an average Canadian household could divert 16 grams of plastic matter from waterways per year, which equals the weight of a 500 ml plastic bottle of soft drink. If we extrapolate this to the scale of the city of Montreal, it indicates a potential of avoiding 12.8 tons of plastic.

Catherine Houbart from GRAME was most surprised, on the one hand, by the amount of microfibers generated in a single home. She commented through a video conference from her office in Montreal, "What is usually invisible became visible." Additionally, she was surprised by the fact that the filter should be inside the washing machine.

"Many candidates ultimately informed us that they could not join the project because they did not have space to place the filter. It would not be realistic for us to stop consuming synthetic fibers. It would be better if these filters were integrated into the machines, like in France," she analyzed.

Starting in 2025, the European country will make it mandatory to sell washing machines with integrated microplastic filters in order to reduce this massive pollution. Meanwhile, the pending question remains of what to do with the collected remains.

In this Canadian experiment, they threw the remains in the trash. The researcher from the Polytechnic University of Montreal concludes, "It is true that the matter does not disappear, what we do is move it around, but I think it is better than releasing them wildly into the environment."