“Wastewater is a huge reservoir of microplastics and nanoplastics,” Aristilde said. “Most people think nanoplastics enter wastewater treatment plants as nanoplastics. But we’re showing that nanoplastics can be formed during wastewater treatment through microbial activity. That’s something we need to pay attention to as our society tries to understand the behavior of plastics throughout its journey from wastewater to receiving rivers and lakes.”