Page - 276 - in Freshwater Microplastics - Emerging Environmental Contaminants?

are found in paints, toys, cosmetics and food packaging, added for the purpose of increasing durability, elasticity, and pliability. Inmedical applications, such as IV bags and tubes, phthalates are prone to leaching after long storage, exposure to elevated temperatures,andasaresultof thehighconcentrationpresent–upto40% byweight [36].Althoughphthalatesmetabolize quickly, in aweekor less,we are exposed continuously through contactwith associatedproducts. WidespreadEffects onMarineLife Of the557 species documented to ingest or entangle inour trash, at least 203 [1]of themarealso ingestingmicroplastic in the wild, of which many are fish [37] and other vertebrates [38, 39]. In addition, laboratory data suggest a growing list of zooplankton [40], arthropods [41],mol- lusks [42], and sedimentworms [43] is also susceptible, alongwithphytoplankton interactionsthatmayaffectsedimentationrates[44]. Inaddition,examplesofclams [45] and fish [46] recovered from fish markets have been found with abundant microplastics in the gut. A study ofmussels in the lab demonstrated that 10 μm microplastics were translocated to the circulatory system [47], leading to studies that now demonstrate evidence that micro- and nanoplastics can bridge trophic levels into crustaceans and other secondary consumers [48, 49]. Ingested microplastic ladenwith polybrominated diphenyls (PBDEs)may transfer to birds [50, 51] and to lugworms [52]. The evidence is growing that there are impacts on individual animals including cancers in fish [53] and lower reproductive success and shorter lifespan in marine worms [43]. Some studies even show impacts to laboratory populations: one studyof oysters concludes that there is “evidence that micro-PS (polystyrene) cause feeding modifications and reproductive disruption [. . .]with significant impacts onoffspring” [54]. While someresearchshows thatplastic canbeavector, or entrypoint, for these toxicants to enter foodwebs, othersdonot. Somestudies ofmicroplastic ingestion have shown that complete egestion follows, as in the marine isopod Idotea emarginata [55], or ingestion of non-buoyant microplastics by the mud snail Potampoyrgus antipodarum, which showed no deleterious effects in development during the entire larval stage [56]. A recent review concluded that hydrophobic chemicals bioaccumulated from natural prey overwhelm the flux from ingested microplastic formosthabitats, implying thatmicroplastic in theenvironment isnot likely to increase exposure [57]. Section Summary These three themes dominate the literature today, with an increasing resolution on ecotoxicology and human health. Understanding the fate ofmicro-andnanoplastics isnecessaryforabetterunderstandingof thedistribution anddispositionofplasticpollution.These themescollectivelyimplymicroplastic is hazardous to the aquatic environment in the broadest sense. As the literature expands, these themes become benchmarks, tools for policymakers, to mitigate foreseenproblemsofmicroplasticcontaminationofallenvironmentsandthesocial impacts theyhaveoncommunitiesworldwide. 276 M.Eriksen et al.