Toward the Development and Application of an Environmental Risk Assessment Framework for Microplastic

Abstract

Emissions of plastic waste to the environment and the subsequent degradation into microplastic particles that have the potential to interact with biological organisms represent a concern for global society. Current understanding of the potential impacts on aquatic and terrestrial population stability and ecosystem structure and function associated with emissions of microplastic particles is limited and insufficient to fully assess environmental risks. Multistakeholder discussions can provide an important element in helping to identify and prioritize key knowledge gaps in assessing potential risks. In the present review, we summarize multistakeholder discussions from a 1-d International Council of Chemical Associations-sponsored symposium, which involved 39 scientists from 8 countries with representatives from academia, industry, and government. Participants were asked to consider the following: discuss the scientific merits and limitations of applying a proposed conceptual environmental risk assessment (ERA) framework for microplastic particles and identify and prioritize major research needs in applying ERA tools for microplastic particles. Multistakeholder consensus was obtained with respect to the interpretation of the current state of the science related to effects and exposure to microplastic particles, which implies that it is unlikely that the presence of microplastic in the environment currently represents a risk. However, the quality and quantity of existing data require substantial improvement before conclusions regarding the potential risks and impacts of microplastic particles can be fully assessed. Research that directly addresses the development and application of methods that strengthen the quality of data should thus be given the highest priority. Activities aimed at supporting the development of and access to standardized reference material were identified as a key research need. Environ Toxicol Chem 2019;38:2087-2100. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Keywords: Effects; Environmental Fate; Exposure; Microplastic; Risk Assessment.

Figure 1

Summary of the challenges identified in implementing an environmental risk assessment framework for microplastic particles, adopted from Romero‐Franco et al. (2017).

Figure 2

Schematic representation of proposed environmental risk assessment framework for microplastic particles, which is based on enabling the characterization of the relationship between the predicted‐environmental concentration and the predicted‐no‐effect concentration.

Figure 3

Schematic representation of ecotoxicity testing matrix, which attempts to account for different types of polymers, shapes and sizes, species, endpoints, and environmental compartments.

Figure 4

Schematic representation of key environmental fate and transport processes of microplastic particles (x‐axis) relative to different spatial scales. Colors illustrate a gradation with respect to temporal scale, with some environmental fate and transport processes requiring short‐, medium‐, and long‐term assessment. The different fate and transport processes may thus require a variety of modeling approaches depending on the temporal and/or spatial resolution required.

Figure 5

Conceptual illustration of innovation benefiting from interdisciplinary collaboration between environmental sciences, waste management, and material sciences.