Microplastics in the Chesapeake Bay and its Watershed: State of the Knowledge, Data Gaps, and Relationship to Management Goals STAC Workshop Report April 24-25, 2019 Woodbridge, VA STAC Publication 19-006 About the Scientific and Technical Advisory Committee The Scientific and Technical Advisory Committee (STAC) provides scientific and technical guidance to the Chesapeake Bay Program (CBP) on measures to restore and protect the Chesapeake Bay. Since its creation in December 1984, STAC has worked to enhance scientific communication and outreach throughout the Chesapeake Bay Watershed and beyond. STAC provides scientific and technical advice in various ways, including (1) technical reports and papers, (2) discussion groups, (3) assistance in organizing merit reviews of CBP programs and projects, (4) technical workshops, and (5) interaction between STAC members and the CBP. Through professional and academic contacts and organizational networks of its members, STAC ensures close cooperation among and between the various research institutions and management agencies represented in the Watershed. For additional information about STAC, please visit the STAC website at http://www.chesapeake.org/stac. Publication Date: October 11, 2019 Publication Number: 19-006 Suggested Citation: Murphy, R., Robinson, M., Landry, B., Wardrop, D., Luckenbach, M., Grubert, K., Somers, K., Allen, G., Trieu, P., Yonkos, L. 2019. Microplastics in the Chesapeake Bay and its Watershed: State of the knowledge, data gaps and relationship to management goals. STAC Publication Number 19-006, Edgewater, MD. 51 pp. Cover graphic: Cover photo courtesy of Masaya Maeda, Anacostia Watershed Society Mention of trade names or commercial products does not constitute endorsement or recommendation for use. The enclosed material represents the professional recommendations and expert opinion of individuals undertaking a workshop, review, forum, conference, or other activity on a topic or theme that STAC considered an important issue to the goals of the CBP. The content, therefore, reflects the views of the experts convened through the STAC-sponsored or co-sponsored activity. Disclaimer: The information in this paper reflects the views of the authors, and does not necessarily reflect the official positions or policies of NOAA or the Department of Commerce. STAC Administrative Support Provided by: Chesapeake Research Consortium, Inc. 645 Contees Wharf Road Edgewater, MD 21037 Telephone: 410-798-1283 Fax: 410-798-0816 http://www.chesapeake.org 2 Workshop Steering Committee: Bob Murphy, Tetra Tech, Center for Ecological Sciences, Co-Chair Matt Robinson, DC Department of Energy & Environment, Watershed Protection Division, Partnering & Environmental Conservation Branch, Co-Chair Brooke Landry, Chesapeake Bay Program SAV Workgroup Chair, Maryland Department of Natural Resources Denice Wardrop, Penn State Mark Luckenbach, Virginia Institute of Marine Science Kimberly Hernandez Grubert, Maryland Department of Natural Resources Kelly Somers, EPA Region III, Water Protection Division Greg Allen, EPA Region III, Chesapeake Bay Program Phong Trieu, Metropolitan Washington Council of Governments Lance Yonkos, University of Maryland Jason Rolfe, NOAA Marine Debris Program Acknowledgments: STAC and the workshop steering committee would like to thank the following individuals for providing expertise and support during and after the workshop: Rachel Dixon, Chesapeake Bay Program Scientific & Technical Advisory Committee Coordinator, Chesapeake Research Consortium Paige Hobaugh, Habitat Goal Implementation Committee Staffer, Chesapeake Research Consortium Annabelle Harvey, Chesapeake Bay Program Scientific & Technical Advisory Committee Coordinator, Chesapeake Research Consortium 3 Table of Contents Executive summary ......................................................................................................................... 5 1. Introduction ............................................................................................................................. 7 1.1 Objectives and Workshop Format .................................................................................... 8 2. Workshop Summary .............................................................................................................. 10 2.1 Brief Summary of Presentations .................................................................................... 10 2.1.1 Introductory Talks ................................................................................................... 10 2.1.2 Sources of Microplastics ......................................................................................... 16 2.1.3 Distribution of Microplastics .................................................................................. 20 2.1.4 Effects of Microplastics on Living Resources ........................................................ 25 2.1.5 Policy and Management .......................................................................................... 27 3. Key Discussion Points ........................................................................................................... 31 3.1 Technical Terminology .................................................................................................. 31 3.2 Sources ........................................................................................................................... 32 3.3 Analytical Methods ........................................................................................................ 34 3.4 Distribution of Microplastics ......................................................................................... 35 3.5 Effects of Microplastics on Living Resources ............................................................... 38 3.6 Monitoring ...................................................................................................................... 39 3.7 Ecological Risk Assessment........................................................................................... 40 4. Recommendations ................................................................................................................. 42 4.1 Recommendation #1: Establish a Plastic Pollution Action at Team at the CBP............ 43 4.2 Recommendation #2: Researching Effects on Living Resources .................................. 43 4.3 Recommendation #3: Complete a Technical Review of Terminology .......................... 44 4.4 Recommendation #4: Address Sources .......................................................................... 45 4.5 Recommendation #5: Monitoring .................................................................................. 45 References ..................................................................................................................................... 47 Appendix A: Workshop Agenda ................................................................................................... 51 Appendix B: Workshop Participants ............................................................................................ 55 Appendix C: Acronyms ................................................................................................................ 57 Appendix D: List of Figures ......................................................................................................... 58 Appendix E: List of Tables ........................................................................................................... 60 4 Executive summary Over the past ten years there has been an exponential rise in the number of technical publications regarding microplastics in the environment. At first, the literature was primarily concerned with characterizing the presence of microplastics in the environment. This research lead to questions about impacts on organisms, with much of the research conducted in Europe. In 2018, the Toxic Contaminants Workgroup of the Chesapeake Bay Program (CBP) Water Quality Goal Implementation Team (GIT) identified microplastics in the bay as an emerging issue of concern in their most recent management strategy. This urgency was largely prompted by findings featured in the 2016 STAC Technical Review of Microbeads/Microplastics in the Chesapeake Bay (Wardrop et al., 2016). A pilot study conducted by Tetra Tech, Metropolitan Washington Council of Governments (MWCOG), and DC Department of Energy and Environment found microplastic in submerged aquatic vegetation (SAV) habitat in the Tidal Potomac River. This prompted the SAV Workgroup to submit a proposal to STAC to support a two-day workshop to identify current knowledge of microplastic pollution in the Chesapeake Bay and potential policy implications. A two-day STAC workshop entitled Microplastics in the Chesapeake Bay and its Watershed: State of the Knowledge, Data Gaps, and Relationship to Management Goals, was convened April 24th – 25th, 2019 at the George Mason University Potomac Science Center in Woodbridge, VA. Over 50 participants from government, academia, consulting, and non-governmental organizations met to present current research and policy initiatives, followed by facilitated discussion on data gaps and needs. The workshop was designed within the framework of an ecological risk assessment (ERA), treating microplastics in the environment similarly to other pollutants. Participants noted that while our understanding has progressed in recent years, we still have little idea of the magnitude and distribution