Page - 2 - in Freshwater Microplastics - Emerging Environmental Contaminants?

1 Introduction Anthropogenic activityhas resulted in thedepositionof a complexcombinationof materials in lake sediments, including synthetic polymers (plastics) that differ greatly from the Holocene signatures. Accordingly, plastics are considered one indicator of theAnthropocene [1]. Plastic has for some time been known to be a majorcomponentof riverinepollution[2–6],andplasticdegradationproductshave beennotedasapotential issueforsoilenvironments [7].However,upuntil recently themainfocusofresearchonplasticpollutionhasbeenthemarineenvironment.To highlight this, a literature searchonThomsonReuters’ ISIWebofScience returns 1,228paperscontainingtheterm ‘microplastic*’,ofwhichonlyasubsetof45publi- cations (3.7%) contains the term ‘freshwater’. This has started to change in recent years, andattention isnowalsobeendirected towardsboth the terrestrial [8,9]and freshwaterenvironments [8,10,11].Thesepublicationspointout the lackofknow- ledge for freshwater and terrestrial environments in terms of the occurrence and impacts of plastics debris. Monitoringstudieshavequantifiedmicroscopicplasticsdebris, so-calledmicro- plastics (MPs), in freshwater systems, including riverine beaches, surface waters and sediments of rivers, lake, and reservoirs [12–19]. Although far less data is availablecomparedtomarinesystems, thesestudieshighlight thatMPisubiquitous andconcentrationsarecomparable [20].Alongside themonitoringdata, ecotoxico- logical studies have mainly exploredMP ingestion by various species and their effects on life history parameters [21–24]. While the majority of studies used primarymicrospheres of polyethylene (PE) and polystyrene (PS) at high concen- trations[25]overshort-termexposures, there issomeevidencethatMPsmayposea risk to freshwater ecosystems [26]. In addition, there is concern that long-term exposure may lead to bioaccumulation of submicron particles with wider impli- cations for environmental health [27–29]. This chapter provides an overview of MPs and the issues, which may be of concern to freshwater environments.Thefirst sectionprovidesabackground to the topic of discussion by describing and defining plastic materials, MPs, emerging contaminants. Subsequent sections then discuss the potential input, fate and trans- portation, effects, and potential riskmanagement options for plastics andMPs in freshwater environments. 2 Plastics andMicroplastics:AnOverview In this section, some context to the topic of environmental MPs is given by (1) providing a brief historical overview of the development of plasticmaterials, (2)describing thecomplexchemical compositionofplasticmaterial, and (3)defin- ingMPsas a contaminants of emerging concern. 2 S.Lambert andM.Wagner