Seite - 157 - in Freshwater Microplastics - Emerging Environmental Contaminants?

aquatic larvaeofChironomusriparius ingest abroadsize rangeofMPs implyinga relative nonselective feeding on sediment components (Table 1 [16]). Surface- grazing gastropods Physella acuta and Potamopyrgus antipodarum as well as the shredder Gammarus pulex have also been shown to ingest MPs through water-/sediment-borne (P. acuta and G. pulex [16]) and food-associated (P. antipodarum andG.pulex [17]) exposure routes. It is unknown if these results are relevant for other benthic deposit feeders considering the diverse ecological niches and feeding types (e.g., collector-gatherer, filter-gatherer, shredders, scrapers). Ananalysisof studiesonMPingestionbyfreshwater species indicates that their general role in the food web (generalist vs. specialized feeders) may determine dietary MP uptake. Generalists (e.g., Daphnia sp.) or deposit feeders like the dipteran C. riparius frequently ingested MPs in laboratory experiments, while this is not the case formore specialized raptorial and carnivorous feeders like the cyclopoidcopepodMesocyclopssp., therotiferAsplanchnasp.aswellas theciliate Didinium sp. (Table 1). However, given the potential of MPs to enter complex aquatic foodwebs at low trophic levels, an indirect ingestion via the prey is also likely for carnivorous predators. For instance, the transfer of MPs via prey was observed in food chain experiments with D. magna and Chaoborus flavicans (personal observation). While the predator C. flavicans did not directly ingest suspended MPs (PS beads, 10 μm), the feeding of MP-containing daphnids (pre-fedonMPs) resulted in an indirect uptakeof 10μmMPs. Table 1 (continued) Uptake (P Ind−1 h−1) Species Insecta Yes (0.05–15.6) Chironomus ripariush No – Mollusca Yes (0.16–104) Anodonta cygneaw,Physella acutah,Potamopyrgus antipodarumI, Sphaeriumcorneumu1–10 No Sphaeriumcorneumu90 Pisces Yes Cathorops agassiziin,Cathorops spixiin,Eucinostomusmelanopteruso, Eugerres brasilianuso,Diapterus rhombeuso,Dorosomacepedianumq, Sciades herzbergiin,Stellifer brasiliensism,Stellifer stelliferm No – a [9], carboxylatedmicrospheres 0.57μm; b [10], plainmicrospheres 0.5μm; c [11], latex beads 0.57–1.05μm;d[12],PSspheres0.5,3,and6μm;e [13], carboxylatedPSspheres0.51μm;f [14], PS spheres 6.5μm(f+) flavored (f−) non-flavored; g [15], carboxylated spheres 2.1, 6.2, 10.8, and 19.4μm;h [16],PSspheres1,10,and90μm; i [17],polymethylmethacrylat29.5±26μm;k [18], PEparticlesandPPfibers10–75μm;m[19],fieldstudy,nylonropefibers;n [20],fieldstudy,nylon fragments; o [21], field study, nylon fragments; q [22],microspheres 10–82μm; s [23], PSbeads, 0.05,0.5, and6μm;upers. observation,PSbeads1,10, and90μm;wpers. observation,PSbeads and fragments 5–90μm.Superscript numbers indicate particle sizes Interactions ofMicroplasticswithFreshwaterBiota 157