Researchers found that the plastic washing process in recycling plants creates microplastics.

They discovered microplastics in water used to clean plastic, and estimated that the plant could emit 6.5 million pounds of microplastics each year, despite using a filter that only catches larger particles. The research did not measure nanoplastics (plastic particles smaller than a specific diameter).

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In this new effort, the research team received permission to test a plastic recycling plant to see if it was emitting plastic pollution.

The problem, the researchers note, is that for plastic to be recycled, it must first be cleaned. This is done by washing it in water several times. The rest of the process involves shredding and melting to create pellets. Prior research has suggested washing may result in the release of microplastics into the water. In this new effort, the group found that the plastic was being washed four times. Each water source was tested to find out how much plastic (in the form of micron-sized particles) remained in the water.

The research team found microplastics in all four sources. They also noted that most of the water is routed to sewage systems or directly into the environment at most recycling plants. After adding up all the particles they observed, the team estimated that the facility could be emitting approximately 6.5 million pounds of microplastics into the environment each year.

But there was more to the story. The researchers revealed that the facility under study had installed a filtration system, which reduced the number of particles by approximately 50%. However, there was a caveat—the researchers only tested for plastics down to 1.6 microns. Plastic particles can be much smaller than that. Prior research has shown that some can be small enough to make their way into individual cells in an animal’s body.

Bob Yirka, Phys.org, May 8, 2023.

Read the full and original news article at Phys.org.

The news article was based on the original research article by Erina Brown et al, The potential for a plastic recycling facility to release microplastic pollution and possible filtration remediation effectiveness, Journal of Hazardous Materials Advances (2023).