Susanne M. Brander, Oregon State University; Jelena Grbic, University of Toronto; Chelsea Rochman, University of California, Davis; Todd Gouin, TG Environmental Research; Amy Lusher, NIVA Norwegian Institute of Water Research; Denise Mitrano, Eawag – Swiss federal Institute of Aquatic Science and Technology; and Sebastian Primpke, Alfred Wegener Institute 

During the recent SETAC North America 39th Annual Meeting in Sacramento, California, the newly formed SETAC Microplastics Interest Group (IG) kicked off with two platform sessions and a well-attended group meeting. The mission of the SETAC Microplastics IG is to support the advancement of scientific research on plastic particles of various sizes that are now ubiquitous in the environment. Key goals of the IG are to support initiatives for the development of standardized methods for the collection, extraction and analysis of microplastic particles (MPs) and fibers from complex environmental matrices, as well as the advancement of science to better understand ecological effects associated with environmental exposure. The presentations given during the two microplastic-related sessions provided a state-of-the-art synopsis that highlighted both the associated challenges and research innovation needed to characterize and quantify the concerns of microplastic in the environment.

Several microplastic-related sessions and events took place at SETAC Sacramento. The increasing interest in the topic led to a great turnout and fantastic discussion. The initial business meeting of the Microplastics IG was also well-attended. The meeting featured two presentations highlighting the needs and opportunities for the sampling and analysis of MPs by Sebastian Primpke, Alfred Wegener Institute, and Jeremy Conkle, Texas A&M. Primpke emphasized the urgent need to harmonize analysis and results reporting so that studies are comparable (e.g., reporting units). He also took the opportunity to draw attention to recent research aimed at developing spectral databases for Fourier-transform infrared spectroscopy (FTIR) data that could be made available to researchers attempting to characterize and quantify MPs observed in environmental samples. Conkle focused on field sampling in watersheds and discussed the need for good quality assurance and quality control (QA/QC). He highlighted the importance of sampling design, which includes the necessity for collecting replicates and blanks. He also proposed new categories for classifying MPs: fully synthetic (e.g., polyester, polystyrene), semi-synthetic (e.g., rayon, linen), natural (e.g., bark powder, chitosan) and other (e.g., calcium stearate, paint). After the presentations, there was a general discussion and participants were interested in having access to methods, best practices and spectral libraries. The discussion continued later that day at a happy hour gathering in downtown Sacramento. Overall, it was clear that there is a need for a community to gather to discuss how we can advance the field of measuring and understanding the environmental fate and exposure of MPs, as well as assessing their environmental risks.

The Microplastics IG has recently contributed to a SETAC Science Brief titled “Plastics Pollution: A Breakdown” and a webinar through Wiley Publishing to be viewed by the World Federation of Science Journalists.

In addition to the formal sessions held during the SETAC North America annual meeting, IG members were also active in the organization and participation of two workshops held just prior to SETAC Sacramento. The Microplastic 2018 Meeting was held from 28–31 October 2018 at the Congressi Stefano Franscini Conference Center in Ascona, Switzerland, hosted by researchers from ETH Zürich, Eawag and the University of Vienna. The meeting included three days of presentations with insights on the development of several important areas of research related to the fate, transport and distribution of particulate plastic (nanoplastics, microplastic particles, microplastic fibers) around the globe. The entire life cycle of plastics was covered, from the production of (macro)plastic to materials flow modeling to consumer and industrial uses of plastic materials and subsequent particulate plastic release or formation in the environment. In this context, many speakers focused on discussions aligned to ecological relevance and a need to better understand the harm and environmental risks associated with the release of plastic, both macro and micro, to the environment. In particular, the environmental fate and transport of MPs in freshwater and urban systems were highlighted, though many of the analytical challenges necessary to measure particulate plastics of all sizes and shapes are common to all environments. These technical considerations for plastic analysis ranged from sample collection to (micro)plastic extraction to chemical analysis. Standardization of analytical methods and understanding “blind spots” in particulate plastic analysis is still paramount, as this underpins the validity and utility of surveys and monitoring studies in the natural environment. Therefore, laboratory-based studies, both for fate and transport as well as biological interactions and effects, are still popular and necessary to understand the basic processes and mechanisms of how particulate plastic moves and behaves in technical and environmental systems.

Breakout discussions, which included all workshop participants, provided an opportunity to reflect on and articulate the key challenges aligned with the development and application of environmental risk assessment methods. The key challenge was focused around the broad theme “Microplastics – the missing links in a risk assessment platform” with three key facets explored: 1) exposure, 2) hazard and 3) risk reduction as well as stakeholder interaction. Given that information on both exposure and hazard are necessary pieces for a risk assessment, participants discussed the current state-of-the-art in these respective sectors and discussed where data was specifically lacking or where improvements could be made in future research. A reliable risk assessment, however, is currently hampered by incomplete knowledge of key processes and pathways of (micro)plastic stemming from both uncertainties related to the quantification of mass flows into the environment as well as the lack of analytical techniques to reliably detect particles, especially in the lower (sub-micron) size range. Discussion then revolved around how all stakeholders (consumers, industry, government) can work together for best practices in managing or reducing risk through different means and initiatives.

There was consensus that (visible) plastic litter impacts our well-being in the environment. Thus, it is important to encourage incentives and innovation that help reduce the flux of (micro)plastic into the environment. It is foreseen, for instance, that application-specific solutions can be developed through collaboration between consumer behavior, economists, regulatory bodies and manufacturers, which may include incentives for plastic use reduction, implementation of proper waste management strategies, the development of biodegradable plastic and a transition from a linear to a circular economy.

Building on the discussions from the Ascona workshop, the International Council of Chemical Associations (ICCA) hosted a one-day, multi-stakeholder symposium on 3 November 2018 in Sacramento that specifically focused on the question of developing and applying an environmental risk assessment (ERA) framework to microplastic. The ERA framework is largely based on the classical chemical risk assessment approach that calculates a Hazard Quotient (HQ) from the ratio of the predicted effect concentration (PEC) and the predicted No-effect Concentration (PNEC).  Participants were divided into one of three breakout groups based on their expertise aligned to exposure and effects assessment or regulatory implementation experience. A key observation from the discussions, participants agreed that an ERA framework should be applicable towards characterizing and quantifying the risks of microplastic; however, there is an urgent need to develop standard analytical methods to help support the acquisition of high-quality data, which is a key objective of the SETAC Microplastic IG.

Consequently, within a short period of time there has been substantial movement towards achieving the goals and objectives of the newly formed Microplastic IG. A key factor in maintaining momentum will be additional activities to ensure research is appropriately aligned towards strengthening the quality of data being produced from microplastic-associated research. This is a critical step in advancing our scientific understanding and will require cooperation between all stakeholders. The multisectoral membership of SETAC provides an excellent forum to help facilitate progress on a currently important issue. To ensure you are kept up-to-date with the latest activities of the group, please join the SETAC Microplastics IG following the guidance on your membership page.

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