Fragmentation of plastic debris and the commercial use of plastic microbeads have led to the widespread distribution of microplastics in natural environments. Several studies have reported on the occurrence and toxicity of microplastics in soils and waters; however, due to methodological challenges, the presence and impact of nanoplastics (<100 nm) in natural systems have been largely ignored. Microbeads used in consumer products such as scrubs and shampoos are processed by mechanical means that may lead to their fragmentation into potentially more hazardous nanoplastics. In this study, three commercial facial scrubs containing polyethylene microbeads (~0.2 mm diameter) were examined to verify whether they contained nanoplastics. Particulates in the scrubs were fractionated using sequential filtration to isolate particles smaller than 100 nm. Scanning electron microscopy was used to confirm the presence of nanoparticles ranging in size from 24 ± 6 nm to 52 ± 14 nm. X-ray Photoelectron Spectroscopy and Fourier Transform Infrared Spectroscopy were used to confirm that the identified nanoparticles consisted of polyethylene. This study confirms the (unexpected) presence of nanoplastics in personal care products containing polyethylene microbeads and highlights the need for further studies to characterize the release and distribution of nanoplastic litter in natural aquatic and soil environments.
Laura M. Hernandez, Nariman Yousefi, and Nathalie Tufenkji, Environ. Sci. Technol. Lett., Just Accepted Manuscript, June 14, 2017