Page - 91 - in Freshwater Microplastics - Emerging Environmental Contaminants?

pollutionbymicroplastics aswell asmanyotherpollutants.Thismight explain the very high abundance ofmicroplastics observed in Taihu Lake and Three Gorges Reservoirs inChina.Therefore, inlandwaters inAsiadeservemoreattention in the future. 3.2 Characteristics of theMicroplastics 3.2.1 ParticleShape After sample collection, potentialmicroplastics are usually examinedusing stereo microscopes.According to their shapes,microplastics are typically categorized as follows: sheet, film, line/fiber, fragment, pellet/granule, and foam (Fig. 1). How- ever, there isnosetprotocol,anddifferentclassificationsmightbeusedbydifferent researchers.Thismorphological information from themicroplastic samples canbe used to indicate their potential origins. For example, line/fiber usually originates fromfishinglines,clothing,orother textiles,whilefilmmainlyoriginatesfrombags orwrappingmaterials. InLakeHovsgol, fragments andfilmswere found tobe the most abundant, together accounting for 78%of the totalmicroplastics [31]. In the ThreeGorgesReservoir, sheet particles andmiscellaneous fragmentswere domi- nant inmost sites [22],whereasfibers and fragmentswerepredominant in samples from Taihu Lake [31]. In inland freshwaters ofWuhan, fiber, granule, film, and pelletwere commonlydetected, andfibersweremost frequentlydetectedaccount- ingfor52.9–95.6%ofthetotalplastics [32].Formicroplasticsamplesfromthefour estuaries inChina, fibers and granuleswere themore abundant [33, 34].Different patternsobserved in these studyareas suggest that the sources of themicroplastics Fig. 1 Shapes of typical microplastics collected from inland waters (Qinghai Lake and Three GorgesReservoir) inChina (a, sheet;b, film;c, line/fiber;d, fragment;e, pellet/granule; f, foam) Microplastic Pollution in InlandWaters FocusingonAsia 91