GBF Report - Polystyrene Foam

18 Seabins have been deployed recently in Lake Ontario in an effort to record and remove surface water plastic and other floating debris. Seabins are relatively new to the Great Lakes and have been installed in the Toronto inner and outer harbours since 2019. Preliminary data shows that 3,127 Styrofoam and foam particles have been collected in Seabins, amounting to 37% of all particles captured (Wu, 2020). In addition to removing plastic, Seabins can serve as an education tool to inform the public about sources of plastic pollution to the environment. Wildlife Foam studies report microplastic contamination in fish and wildlife within the Great Lakes area, and of these, three studies have shown foam ingestion 3 . Wagner et al., (2019) observed microplastics in three fish species, and PS foam (75 um) was observed in Salvelinus fontinalis (Lake Trout) from Lake Huron. Another fish study investigating fish in Lake Michigan tributaries found eleven fish species ingested microplastics, although no foam was found (McNeish et al., 2018). Multiple bird species on the Great Lakes have been shown to ingest plastic, and two of three studies have reported PS. Holland et al. (2016) recorded anthropogenic debris including plastic in Anas platyrhynchos (Mallard Duck) on Lake Ontario, although no foam was observed. Brookson et al. (2019) found poly(divinyl benzene): styrene (PS crosslinked with divinylbenzene) in Phalacrocorax auritus (Double-crested Cormorant) chicks on Lake Ontario, showing that adult birds are feeding plastic, including PS, to their young. Thaysen et al. (in review) found large pieces EPS in Larus delawarensis (Ring-billed Gull) on the St. Lawrence River. No studies to date have investigated microplastic ingestion in birds on Lake Huron. Results from these five studies show that PS and other anthropogenic debris contaminate wildlife in Great Lakes. Still, we have a limited understanding of the extent that polystyrene foam and other plastic contaminate Great Lakes species. Research is underway to understand the effects of environmentally relevant microplastics to Great Lakes species. Many studies have investigated the effects of PS ingestion in freshwater and marine animals in habitats around the world. 3.5 Ingestion by fish and wildlife Many observations demonstrate that PS foam is frequently found in the environment, often as one of the most common microplastic types (Derraik, 2002; Browne et al., 2007; Barnes et al., 2009). It has been shown in studies in the wild and in laboratories that PS foam is ingested by many different species and include organisms with different strategies. In the wild, PS foam has been found in the stomachs of several animals including numerous species of fish (Boerger et al., 2010), sea turtles (Jung et al., 2018; Schuyler et al., 2014), bivalves (Jang et al., 2016), and birds (Brookson et al., 2019; Thaysen et al., in review). Some animals like birds can transport PS foam between aquatic and terrestrial environments. Organisms such as zooplankton presumably consume PS passively withphytoplankton prey in non-selective feeding (K.-W. Lee et al., 2013). Scrapers and grazers such as freshwater snails likely consume PS that is on the sediment surface (Scherer et al., 2017). Selective filter feeders like copepods (Cole et al., 2015), oysters (Sussarellu et al., 2016), and mussels (Rist et al., 2019) likely ingest foam that is suspended in water. Given the ubiquity of PS in the environment, it would be desirable to be able to attribute particles that were ingested by animals in the wild with a particular source. However, a major challenge to this is that PS found in animals are often observed as small fragments (i.e. Boerger et al., 2010). In some cases, ingested PS is in its “raw” fragment form, and could possibly originate from pellet spills or losses in manufacturing (Jung et al., 2018; Kartar et al., 1976). While many studies hypothesize potential sources of ingested PS, the specific sources can vary. Although many studies rely on best guesses, some studies are able to make very strong cases. For example, in mussels growing on PS floats, foam microplastics identified inside mussels probably originate from their substrates (Jang et al., 2016). Identifying sources in free swimming organisms can be more challenging. 3 One study to date has investigated plastic ingestion by wildlife in Lake Huron (Wagner et al., 2019), and no studies were found that investigated plastic ingestion by wildlife in Georgian Bay Zooplankton and Phytoplankton Tiny “drifters,” plankton are alive, aquatic, and adrift. All plankton are essential for the stability of aquatic food webs. Zooplankton are small (sometimes one-celled) animals. Phytoplankton are photosynthetic organisms.

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