The accumulation of plastic litter in natural environments is a global issue. Concerns over potential negative impacts on the economy, wildlife, and human health provide strong incentives for improving the sustainable use of plastics. Despite the many voices raised on the issue, we lack a consensus on how to define and categorize plastic debris. This is evident for microplastics, where inconsistent size classes are used and where the materials to be included are under debate. While this is inherent in an emerging research field, an ambiguous terminology results in confusion and miscommunication that may compromise progress in research and mitigation measures. Therefore, we need to be explicit on what exactly we consider plastic debris. Thus, we critically discuss the advantages and disadvantages of a unified terminology, propose a definition and categorization framework, and highlight areas of uncertainty. Going beyond size classes, our framework includes physicochemical properties (polymer composition, solid state, solubility) as defining criteria and size, shape, color, and origin as classifiers for categorization. Acknowledging the rapid evolution of our knowledge on plastic pollution, our framework will promote consensus building within the scientific and regulatory community based on a solid scientific foundation.

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Are We Speaking the Same Language? Recommendations for a Definition and Categorization Framework for Plastic Debris.

Plastic pollution accumulating in an area of the environment is considered “poorly reversible” if natural mineralization processes occurring there are slow and engineered remediation solutions are improbable. Should negative outcomes in these areas arise as a consequence of plastic pollution, they will be practically irreversible. Potential impacts from poorly reversible plastic pollution include changes to carbon and nutrient cycles; habitat changes within soils, sediments, and aquatic ecosystems; co-occurring biological impacts on endangered or keystone species; ecotoxicity; and related societal impacts. The rational response to the global threat posed by accumulating and poorly reversible plastic pollution is to rapidly reduce plastic emissions through reductions in consumption of virgin plastic materials, along with internationally coordinated strategies for waste management.

The global threat from plastic pollution

Tackling the plastic problem: A review on perceptions, behaviors, and interventions.

We report for the first time the ingestion of microplastics by scleractinian corals, and the presence of microplastics in coral reef waters adjacent to inshore reefs on Australia’s Great Barrier Reef (GRE, 18°31′S 146°23′E). Analysis of samples from sub-surface plankton tows conducted in close proximity to inshore reefs on the central GBR revealed microplastics, similar to those used in marine paints and fishing floats, were present in low concentrations at all water sampling locations. Experimental feeding trials revealed that corals mistake microplastics for prey and can consume up to ~50 μg plastic cm−2 h−1, rates similar to their consumption of plankton and Artemia nauplii in experimental feeding assays. Ingested microplastics were found wrapped in mesenterial tissue within the coral gut cavity, suggesting that ingestion of high concentrations of microplastic debris could potentially impair the health of corals.

Microplastic ingestion by scleractinian corals

https://pure.knaw.nl/ws/files/12349954/6829_Qi_AAM.pdf

Effects of plastic mulch film residues on wheat rhizosphere and soil properties

In recent years the littering of plastics and the problems related to their persistence in the environment have become a major focus in both research and the news. Biodegradable polymers like poly(lactic acid) are seen as a suitable alternative to commodity plastics. However, poly(lactic acid) is basically non-degradable in seawater. Similarly, the degradation rate of other biodegradable polymers also crucially depends on the environments they end up in, such as soil or marine water, or when used in biomedical devices. In this Minireview, we show that biodegradation tests carried out in artificial environments lack transferability to real conditions and, therefore, highlight the necessity of environmentally authentic and relevant field-testing conditions. In addition, we focus on ecotoxicological implications of biodegradable polymers. We also consider the social aspects and ask how biodegradable polymers influence consumer behavior and municipal waste management. Taken together, this study is intended as a contribution towards evaluating the potential of biodegradable polymers as alternative materials to commodity plastics.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/anie.201805766

Plastics of the Future? The Impact of Biodegradable Polymers on the Environment and on Society

https://onlinelibrary.wiley.com/doi/pdf/10.1002/gch2.201900010

On the Creation of Risk: Framing of Microplastics Risks in Science and Media

Superficial or Substantial: Why Care about Microplastics in the Anthropocene?

Kunststoffe der Zukunft? Der Einfluss von bioabbaubaren Polymeren auf Umwelt und Gesellschaft

Microplastic pollution has sparked interest from researchers, public, industries, and regulators owing to reports of extensive presence of microplastics in the environment, household dust, drinking water, and food, which indicates chronic exposure to organisms within ecosystems and in human living spaces. Although exposure to microplastics is evident, negative effects from microplastics appear to be minimal in most studies on biota, and no risk assessments have been completed for microplastics on human health. Despite current evidence that indicates that microplastics present low risk to biota, there is public perception that microplastics are a serious environmental and human health risk, and this perception has motivated political action. The discrepancy between scientific evidence and public risk perception has generated debate among researchers within the natural and social sciences. Here, we review the evidence on the risks of microplastics to ecosystem and human health and consider the relation between evidence and public perception of microplastics risk.

Johanna Kramm

Papers

Plastics of the Future? The Impact of Biodegradable Polymers on the Environment and on Society

On the Creation of Risk: Framing of Microplastics Risks in Science and Media

Superficial or Substantial: Why Care about Microplastics in the Anthropocene?

Kunststoffe der Zukunft? Der Einfluss von bioabbaubaren Polymeren auf Umwelt und Gesellschaft

Risk posed by microplastics: Scientific evidence and public perception