Your kitchen sponge may be generating pollution every time you wash dishes, according to a new study — but the same scientists say there’s an even bigger environmental concern at play.

Researchers from Germany’s University of Bonn found that kitchen sponges may be releasing a statistically significant amount of microplastics, according to a study published in the journal Environmental Advances in February. The article reveals that kitchen sponges that contain plastic material gradually wear down during everyday use, releasing microplastics into wastewater.

Microplastics are teeny, tiny plastic particles that measure smaller than 5 millimeters and have been found in seafood, vegetables, and even the human brain. They have an even smaller counterpart, known as nanoplastics, which are about 1 nanometer wide, or 1/70th the width of a human hair.