Plastic debris was long considered “just litter”, unsightly, but environmentally and toxicologically innocuous. Concern later arose regarding large debris and attendant impacts on charismatic marine mega-fauna, e.g. marine mammals. Fragmentation into what we currently denote as micro- and nanoplastics (MNPs) was initially viewed as beneficial. But we now recognize that MNPs can be problematic, eliciting consequences at multiple ecosystem levels. Global plastic demand and environmental release are exacerbated by a lack of economic incentives that would constrain manufacture and encourage recycling. Plastic products are compositionally diverse, composed of a variety of polymers. Chemical additives may be present at % levels of the polymer mass and their fate must be considered in the design of degradable/nontoxic products. Some additives (e.g. flame retardants and metals) are persistent, bioaccumulative and toxic (PBT) chemicals. While the oceans are plastic debris sinks, most enter via terrestrial sources. Plastics may be altered physically or chemically, both during use and following discard (e.g. via abrasion, photolysis, biodegradation, hydrolysis and contaminant sorption). Ambient environmental conditions further influence plastic biogeochemical fate and toxicological consequences. Physical processes such as hydrodynamics alter debris distributions/concentrations and hence organismal exposure. Factors such as water temperature, dissolved organic carbon content and digestive fluids can alter release of additives and sorbed pollutants. Fragmentation increases plastic surface areas, influences biofilm formation, polymer degradation rates, additive migration and contaminant sorption. Complexity of MNP sampling and analytical detection are increased due to the diversity of their composition, particle shape and size. Identification and quantitation of particles &lt;20 μm are particularly difficult. This impedes our ability to evaluate MNP characteristics, as well as their fate and ecosystem consequences. Health effects are primary concerns, but to date, have been inadequately assessed. Impacts may relate to physical (e.g. digestive system blockage or tissue abrasion) or chemical (e.g. toxic additives from tire wear and bioaccumulation of chemicals) attributes of plastic debris. Hence, there remains much work to do related to evaluating the concentrations, characteristics and health (both human and ecosystem) repercussions of plastics in the global environment.

Progress and challenges related to plastics in the ocean

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.