Presentation Abstracts Key Note Address: The state of knowledge on - PDF document

Presentation Abstracts Key Note Address: The state of knowledge on microplastics and their impact on environmental health Kara Lavender Law, Sea Education Association Environmental pollution by microplastics has quickly become a major concern to the public, the media, policymakers and scientists because of their widespread occurrence and potential impacts to wildlife and human health. As early as the 1970s, microplastics - typically defined as plastic particles smaller than 5 mm - were found drifting in the open ocean. By the 2010s, microplastics had been detected throughout the marine, freshwater and terrestrial environment, and also in many items commonly consumed by humans. Despite accelerated scientific research into the effects of microplastics exposure, no broad conclusions can yet be drawn. Session 1: Understanding the Prevalence of Microplastics in the Environment Characterising microplastics in the context of risk assessment Bart Koelmans, Wageningen University What can be considered ‘best practices’ for measuring plastic in the environment, depends on the context in which the measurements are done. Often this is either understanding risks and impacts on the environment and human health, or monitoring, i.e. keeping track of trends of pollution with plastic over space and time. To get application and analytical approach aligned, we first require a thorough understanding of what microplastic actually is, how we can describe it, how it moves in the environment and how it interacts with organisms including humans. Once this is clear, one can assess quality assurance and control (QA/QC) criteria in order to design analytical methodologies that are fit for purpose. In this presentation a framework is provided, unifying QA/QC criteria, measurement targets, and risk- as well as monitoring goals in order to consistently address the complexity of environmental plastics. Innovative technologies for polymer identification Jennifer M. Lynch, National Institute of Standards and Technology and Hawaii Pacific University Polymer identification is now expected in most plastic pollution studies. Each polymer has different chemistry, uses, disposal processes, environmental fates, additive chemicals, affinities for contaminants, thus potentially different impacts on the environment. It is important to understand the chemistry behind the pollutant in the study’s environment. Methods that do not include chemical identification of the pollutant (e.g., visual determinations among other methods) can underestimate or overestimate plastic quantities. This presentation will discuss common and novel methods used for polymer identification of microplastic samples. On-going research projects will be presented for sample preparation (isolation of microfibers from larval fish and microplastics from beach sand) and polymer identification (4-step workflow for accurate and

complete identification of multi-layer composites, benefits and limitations of uFTIR and uRaman for microfibers). A brief overview of NIST’s capabilities for nanopastic metrology will also be given. Session 2: Understanding the Effects of Microplastics on Human Health Data Needs to Evaluate Human Exposures to Microplastics in Air & Water Greg Zarus, Agency for Toxic Substances and Disease Registry Microplastics pervade our environment. Human exposure is certain; however, exposure-dose and possible health effects have not been established. It is clear that some microplastic fibers and particles are small enough to become internalized and transported within our bodies. However, most of the samples collected in the environment have been characterized as larger particles that are unlikely to be absorbed. Unlike other substances in our environment, the quantities or masses of the microplastics most likely to cause harm to humans are not often investigated. Furthermore, the methods for identifying and measuring the particles vary such that it is difficult to compare the results of different studies. The Agency for Toxic Substances and Disease Registry (ATSDR) has a method to assess human exposures to many toxic substances. This method involves using environmental and biological data collected stringent sampling methods. We detail the ATSDR assessment method to show which critical data are lacking to accurately estimate human exposure and effects. We will demonstrate that: 1) Most human exposure media are not sampled; 2) Small sized microplastics are seldom measured; 3) Sample analysis results seldom include mass measurements; 4) Studies of human and animal health effects are too few and too limited; 5) Dose response data has not been adequately demonstrated. ATSDR along with the National Center for Environmental Health developed a microplastics workgroup, with a vision and strategies to: 1) Develop the science and resources to define and prioritize the health risks; 2) Create constructive partnerships to broaden outreach; Energize communities and institutions to develop initiatives to stop harmful microplastic exposures in our environment. Microplastics in Seafood Garth Covernton, Ph.D. Candidate, Department of Biology, University of Victoria (remote) Both scientific papers and the media tend to present seafood as one of the top sources of microplastics in the human diet. Studies of seafood have focussed on the extent and effects of microplastics in aquatic systems, especially in commercially important species. Due to this bias in the literature, the best data on the levels of microplastics present in human food thus exist for seafood, resulting in it being the most talked about source. Another by-product of the larger number of studies conducted on seafood has been the common idea that marine animals are the most at risk of health effects caused by microplastic pollution. Marine food webs are often presented as ‘accumulating’ microplastics, with the implication that animals which feed higher in the food chain, including humans, will be most exposed to microplastics. This talk will dispense some of these myths and provide evidence towards the ideas that 1) while seafood is the best

understood source of microplastics in the human diet, the evidence does not support it being the highest source of exposure, 2) marine animals may actually be at lower risk of exposure to microplastics relative to terrestrial and freshwater individuals, and 3) microplastics have thus far not been found to be magnifying in aquatic food webs, suggesting that organisms feeding lower in the food chain may be at the highest risk of ingesting microplastic, and that the primary source of human exposure to microplastics is unlikely to be microplastics ingested by seafood species. Adverse Effects of Microplastics in Aquatic Ecosystems are Questionable Allen Burton, University of Michigan The science on the occurrence, fate and effects of microplastics (MPs) in aquatic ecosystems is growing rapidly, with ~150 peer-reviewed publications in 2016 increasing to near 1,000 in 2019. In ecotoxicology, new topics over the past 3 decades show a similar maturation, with an initial focus raising the alarm of a potential problem, followed by method development, then later fully characterizing the extent of the problem by linking exposures with effects. Such is the case for MPs over the past 5 to 6 years. The science has now documented MPs in the ~100 to 500 micron size are widespread, with highest levels in large waterways dominated by untreated urban sewage. Significant adverse effects identified in laboratory experiments occur at unrealistically high exposures. MPs are not a significant vector for contaminant uptake and bioaccumulation, as compared to consumption of contaminated prey. The concentrations of MPs within the gut of aquatic organisms do not reach problematic levels, as compared to well-known physical damage by macroplastics. MPs will continue to accumulate in depositional sediments and may reach levels of ecological concern; but, likely sediment-sorbed contaminants will continue to dominate as stressors. Nevertheless, there is high uncertainty of whether MPs smaller than 100 microns (including nano-sized particles) are an ecological threat, as their numbers can be much higher, more toxic, yet difficult to assess. These very small plastics and particles (e.g., anti-fouling paint chips) should be an ecological risk research focus in “at risk” environments. Session 3: Reducing Microplastics in the Environment No Plastic in Nature: Preventing secondary sources of microplastic in the environment Rebecca Traldi, World Wildlife Fund Only 18% of plastic globally is estimated to be recycled, and over 10% of plastic is mismanaged (Geyer et al. 2017, Jambeck et al. 2015). The leakage of plastic into nature is an ongoing and worsening environmental crisis, exacerbated by inadequate infrastructure, rapid consumption growth, and numerous perverse incentives in the broader materials system. World Wildlife Fund (WWF) has set an ambitious goal of No Plastics in Nature by 2030, targeting engagement with cities, companies, policy-makers, and the public. This presentation, which focuses on secondary microplastics, discusses WWF’s efforts to achieve this goal with the private sector through the ReSource: Plastic program which launched in 2019. ReSource: Plastic enables investigation of the fate of plastics in company supply chains, with a holistic approach that accounts for trade-offs and complexity.