CAREER: Untangling the Impacts of Microplastic Weathering on the Fate and Transport of Halogenated Organic Compounds

Microplastics are tiny plastic particles that accumulate in the environment. This project will study how microplastics move through soil and water and interact with potentially toxic chemicals, such as chlorinated ethenes and per- and polyfluoroalkyl substances (PFAS). The research will explore the fate of microplastics in the environment by conducting a series of laboratory experiments of increasing scale and complexity under conditions that mimic those of contaminated sites. Results of the project will advance scientific knowledge that can be used to protect public health, remediate contaminated sites, and protect water supplies. Although the interactions between microplastics and halogenated organic compounds (HOCs) are recognized, fate and transport and risk models do not capture the critical roles and dynamics of these interactions. This CAREER project aims to address these critical gaps by exploring the fate and transport of microplastics and their interactions with the associated adsorbed HOCs in soil and groundwater environments. The specific objectives are to: (1) evaluate the impacts of aged and weathered microplastics on HOC adsorption and kinetics; (2) assess the impacts of weathering and aging of HOC-adsorber microplastics on HOCs biotransformation, and resolve how microbial community composition differs at the microplastic and soil interface; (3) evaluate the effects of flow (e.g., simulated rainfall events) on the fate and transport of microplastics and adsorbed HOCs in the unsaturated zone and at the water table; and (4) create programs to disseminate knowledge about the impact of HOCs and microplastics on water quality. The project will generate critical data for improving mathematical transport models and conceptual site models, leading to more representative risk and exposure predictions. Additionally, the project will provide valuable insights into the potential for soil and subsurface microbial communities to affect the fate of microplastics and HOCs. Overall, this research will contribute to the protection of soil health and drinking water supplies, ultimately promoting environmental sustainability and public health. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.