Microplastics (MPs) and nanoplastics (NPs) are an emerging contaminant that can serve as a vector for other harmful pollutants. However, current MP research is largely based on experiments with monodisperse, uniform particles. In reality, environmental MPs are more heterogenous in size and shape and are transformed upon entering the environment. There is a critical need to generate environmentally relevant MPs to better investigate MP interactions with organic compounds in laboratory experiments. Further, eco-corona formation, or interaction with Natural Organic Matter (NOM), is a surface specific interaction that can dictate particle behavior and mobility. The objective of this study is to characterize and quantify eco-corona formation and its impact on environmentally relevant MPs. Cryogenic grinding, or cryomilling, was successfully utilized to transform polystyrene (PS) bulk material into heterogenous micro and nano fragments. Additionally, an ultraviolet light aging chamber was employed to simulate sunlight on the cryomilled fragments. Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) were used to measure changes in surface chemistry due to photooxidation and cryomilling of plastics. Cryomilling didn鈥檛 alter the surface chemistry of the plastic. UV aging increased the oxygen content on the particle surfaces. Coulter counter and Nanoparticle Tracking Analysis (NTA) were also used to measure the size distributions of the micro- and nano- size fractions of the generated MPs. Ongoing work includes eco-corona formation experiments utilizing 3 main components of NOM (proteins, humic substances, and polysaccharides). Adsorption isotherms coupled with Quartz Crystal Microbalance with Dissipation (QCM-D) and XPS surface chemistry measurements will be utilized to better understand organic compound interaction with MP surfaces and the impacts of eco-corona formation on pollutant adsorption and particle stability. These transformation processes (UV aging, and eco-corona formation) are likely to have impacts on the adsorption of organic and inorganic pollutants, as well as MP transport and fate.
I am a 5th year PhD candidate in environmental engineering working in the Nason Lab group at 精东影视 State. I earned my bachelor鈥檚 degree in Chemical and Life Science Engineering from Virginia Commonwealth University in 2016. After graduating I worked for Sabra Dipping Company as a Production Supervisor, volunteered as a Water Quality Monitor for the James River Association, and worked as a public-school substitute teacher. I have completed the Graduate Certificate in College and University Teaching, conducted engineering education research during my tenure at OSU, and have a passion for engineering education. My research focuses on the interactions between natural organic matter and microplastics in aquatic environments. Here I investigate the formation of an 鈥渆co-corona,鈥 or natural organic matter coating, on environmentally relevant microplastics to better understand how these contaminants are transformed and behave in our environment.