Formation and Identification of Small Microplastics and Nanoplastics

Plastic production has continued to increase globally and is now a major contaminant across different environments and water systems. Plastic pollution consists of large intact pieces, but also small, fragmented pieces of plastic, termed microplastics (mm) and nanoplastics (um). Small micro- and nanoplastics display different properties than the larger plastic pieces, prompting further chemical investigation and concern related to human and environmental health. We recently determined that using a solubilizer, small microplastics and nanoplastics form readily in water. We used common stock and real-world plastics, such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polycarbonate. We analyzed how different mixing techniques, solubilizer concentration, and plastic types affect particle size. We also probed the role of the solubilizer after creating nanoplastics and methods to identify the presence of nanoplastics in water. Small micro- and nanoplastics are created by forceful hand shaking, and ultrasonic mixing can be used to make smaller particles. Organic solvents extracted the majority of certain solubilizers and extended heating was also effective for the removal of the solubilizer. We have used Nile Red as an indicator of the presence of nanoplastics in pure water. We expect that these findings will expand research abilities on these plastic particles, especially those made from real-world plastics. The ease of this nanoplastic formation regardless of technique is also concerning, as it suggests they are more abundant and bio-available in natural environments than currently estimated