Current wastewater treatment processes may not effectively filter microplastic contamination, according to new research. This may cause potential issues for human health and aquatic environments as the accumulation of plastic continues to increase globally.

To understand how microplastic pollution breaks down and interacts with water and wastewater treatment processes, scientists measured the efficiency of current wastewater treatment processes to remove nano and microplastics measuring less than 5 millimeters in size, publishing their findings in Water Research. They found that processes used to purify used water may break down tiny pieces of plastic even further, posing concern for the quality of treated water.

"The presence of nano and microplastics in water has become a major environmental challenge. Due to their small size, nano and microplastics can easily be ingested by living organisms and travel along water and wastewater treatment processes,” said study author Judy Lee in a statement. “In large quantities, they impact the performance of water treatment processes by clogging up filtration units and increasing wear and tear on materials used in the design of water treatment units."

According to the study, an estimated 300 million tons of plastic is produced around the world every year – 13 million of it is released into rivers and oceans. If that remains steady, current projections suggest that there will be 250 million tons of plastic in waterways by 2025. Because plastic does not degrade through weather or other aging processes, the accumulation of it in water systems around the world as the potential to threaten aquatic environments and human health. But detecting the presence of tiny plastic contaminants remains a challenge.

“A key challenge in their detection resides in the relatively inadequate analytical techniques available preventing deep understanding of the fate of nano/microplastics in water,” wrote the study authors, adding that the occurrence of such microscopic plastic pollution in water and wastewater treatment plants pose “a concern for the quality of the treated water.”

Microplastics come in all shapes and sizes and are made of a variety of different materials, making their detection in water treatment systems particularly challenging. Furthermore, different treatment processes may affect plastics, whose chemical makeup varies greatly, in different ways. To combat this, researchers say new strategies are needed to better understand how treatment processes can be effective and accurate in order to meet required safety standards, thereby reducing potential threats to ecosystems.