Plastic pollution is one of the most visible and complex environmental issues today. Interested and concerned parties include scientists, governmental agencies, non-governmental organizations, industry, media, and the general public. One key assumption behind the issue and the public outcry is that plastics last indefinitely in the environment, resulting in chronic exposure that harms animals and humans. But the data supporting this assumption are scant. The first half of this talk will describe several eye-opening findings from the first review of infographics that report the environmental lifetimes of plastics. In total, 57 graphics from 13 countries were reviewed, totaling 255 estimates for the environmental lifetime of common plastic consumer goods. The second half of the talk will focus on the photochemical fates of several commodity plastics in the ocean. It is often assumed that sunlight merely fragments plastic into smaller and smaller particles over time (i.e., macroplastics to microplastics). Current evidence now indicates that sunlight exposure transforms plastics into oxygenated products that span the polymer, dissolved, and gas phases. Examples of plastic photochemical degradation into dissolved organic compounds and carbon dioxide will be discussed. Furthermore, the shading of plastic by biofilms, a potential impediment of plastic photodegradation, will be discussed. Our collective findings indicate that plastic formulation, including the presence of organic and inorganic additives, is a fundamental control of the photochemical fate of plastics in the ocean. Therefore, an accurate understanding of the lifetime, behavior, and potential risks of plastics to marine life and humans will require consideration of plastic formulation, not just the base polymer used in plastic goods.

Insights into the perceived persistence and photochemical fate of plastics in the ocean

ACS Spring Meeting 2021

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