The scientific consensus emphasizes size as the critical factor distinguishing micro- and nanoplastics, with nanoplastics posing heightened risks due to their ability to penetrate cells and tissues. Researchers focus on developing reliable detection techniques and toxicity assays to quantify exposure and biological effects, acknowledging current methodological limitations in isolating nanoplastics from complex matrices. These challenges hinder risk assessment and regulatory responses, underscoring the need for standardized protocols and interdisciplinary collaboration.