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Assessing Effects of Nano- and Microplastics in Aquatic Environments
Citation:
Zepp, R., Brad Acrey, W. Wohlleben, E. Sahle-Demessie, AND S. McWhorter. Assessing Effects of Nano- and Microplastics in Aquatic Environments. SETAC North America 43rd Annual Meeting, Pittsburgh, PA, November 13 - 17, 2022.
Impact/Purpose:
There is a rising concern regarding the accumulation of floating plastic debris in the open ocean and freshwaters. However, the magnitude and the fate of this pollution are still open questions. In particular, the ecological risks of microplastics (MPs) are closely linked to their exposure concentrations in aquatic environments. One significant source of MPs involves combined UV-initiated and mechanical fragmentation of macroplastics into smaller and smaller sizes. Because exposure to UV radiation affects these characteristics, it may play a key role in regulating potential toxicity and ecological impacts of microplastics. Here we report our recent efforts to use the ISO-4892-2 protocol for testing plastics degradation and to develop methods for evaluating the fragmentation of macroplastics and MP by weathering into “secondary”, smaller MP with concurrent release of associated chemicals, including carbon nanotubes and graphene oxide.
Description:
Microplastics (MPs) (defined as plastic particles < 5 mm in size) and microfibers are widely distributed in terrestrial and aquatic ecosystems. The plastics are often combined in composites with nanomaterials such as carbon nanotubes or graphene oxide that maximize desirable properties such as strength, conductivity, and antibacterial activity. Assuming current trends in production and no improvements in waste management, releases of MPs into the environment may grow to 90 metric tons per year by 2030. The ecological risks of MPs are closely linked to their exposure concentrations in aquatic environments. One significant source of MPs involves combined UV-initiated and mechanical fragmentation of macroplastics into smaller and smaller sizes. This process may also be an important pathway for the eventual removal of plastic particles from the environment. For example, exposure to UV radiation on the ocean surface can transform common plastics such as polystyrene into CO2 and dissolved organic carbon. Across ecosystems, many of the effects of microplastics are influenced by their physical characteristics, including particle size and shape. Because exposure to UV radiation affects these characteristics, it may play a key role in regulating potential toxicity and ecological impacts of microplastics. Here we report our recent efforts to use the ISO-4892-2 protocol for testing plastics degradation and to develop methods for evaluating the fragmentation of macroplastics and MP by weathering into “secondary”, smaller MP with concurrent release of associated chemicals, including carbon nanotubes and graphene oxide.
