Seite - 154 - in Freshwater Microplastics - Emerging Environmental Contaminants?

natural particles may be similar, future research needs to benchmark synthetic against natural materials. Finally, given the scale of the research question, we need a multidisciplinary approach to understand the role of microplastics in a multiple-particleworld. Keywords Autecology, Feeding types,Microplastic-biota interaction, Polymers, Suspended solids,Vector 1 Introduction Over thepast decade,microplastics (MPs)havebecomeaprominent environmental concern, mainly because of their frequent and ubiquitous detection inmarine and freshwaterecosystems.Therefore,biotawill likelyencounter and interactwithMPs. In addition, MPs are a heterogeneous class of pollutants with a broad range of individual properties such asmaterial type, particle size, and particle shape. These diversematerial characteristicsmake thempotentially available to a broad rangeof neustonic (buoyantmaterials,density<1gcm 3),pelagic (materials insuspension), andbenthicspecies(sedimentingmaterials,density>1gcm 3).ThisenablesMPsto penetrate aquatic foodwebsatmultiple trophic levels andecological niches. Todate, research intoMPexposure for freshwater biota is limited.Yet,marine researchhas shownmalnutritioncausedby the intensive feedingonMPs replacing partsof thenaturaldiet [1–3].Additionally, further ingestion-relatedeffects include blockages and injuries to the digestive tract [4], inflammatory response [5], and desorptionofxenobiotics [6].Obviously, all of these responsespresuppose feeding and ingestion ofMPs. As such, the aim of this chapter is to discuss the diverse interactionsbetweenMPsandbiota thatmayoccur in the environment. In thefirst section, we focus on factors influencing the ingestion of MPs considering the impact of the different physical properties ofMPs and feeding types of freshwater species. In thesecondsection,weprovideanoverviewandanalysisof theobserved MPeffects in termsof their physical, chemical, andvector-related impacts.This is followed by a comparison of the similarities in the effects caused by exposure to naturallyoccurringparticlesandMPs.Finally,weconcludebydiscussingthewider implications ofMPs toward freshwater systems. 2 Factors InfluencingMicroplastic Ingestionby FreshwaterBiota Species in freshwater ecosystems are part of complex foodwebs and forage on a wide diversity of food types, utilizing a variety of different feeding strategies. Notwithstanding this diversity, the classification by feeding types or by food types is commonly used to group biota. For instance, suspension feeders obtain nutrients fromparticles suspended inwater, deposit feeders forage for particles in 154 C.Scherer et al.