title: Responses of Hyalella azteca to acute and chronic microplastic exposures.
abstract: Limited information is available on the presence of microplastics in freshwater systems, and even less is known about the toxicological implications of the exposure of aquatic organisms to plastic particles. The present study was conducted to evaluate the effects of microplastic ingestion on the freshwater amphipod, Hyalella azteca. Hyalella azteca was exposed to fluorescent polyethylene microplastic particles and polypropylene microplastic fibers in individual 250-mL chambers to determine 10-d mortality. In acute bioassays, polypropylene microplastic fibers were significantly more toxic than polyethylene microplastic particles; 10-d lethal concentration 50% values for polyethylene microplastic particles and polypropylene microplastic fibers were 4.64 × 10(4) microplastics/mL and 71.43 microplastics/mL, respectively. A 42-d chronic bioassay using polyethylene microplastic particles was conducted to quantify effects on reproduction, growth, and egestion. Chronic exposure to polyethylene microplastic particles significantly decreased growth and reproduction at the low and intermediate exposure concentrations. During acute exposures to polyethylene microplastic particles, the egestion times did not significantly differ from the egestion of normal food materials in the control; egestion times for polypropylene microplastic fibers were significantly slower than the egestion of food materials in the control. Amphipods exposed to polypropylene microplastic fibers also had significantly less growth. The greater toxicity of microplastic fibers than microplastic particles corresponded with longer residence times for the fibers in the gut. The difference in residence time might have affected the ability to process food, resulting in an energetic effect reflected in sublethal endpoints.
authors.affiliation: Institute of Environmental Toxicology, Clemson University, Pendleton, South Carolina, USA.|Interdisciplinary Graduate Program in Environmental Toxicology, Clemson University, Clemson, South Carolina, USA.
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Au
authors.affiliation: Clemson Light Imaging Facility, Clemson University, Clemson, South Carolina, USA.
authors.forename: Terri F
authors.initials: TF
authors.lastname: Bruce
authors.affiliation: Department of Mathematical Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Bridges
authors.affiliation: Institute of Environmental Toxicology, Clemson University, Pendleton, South Carolina, USA.|Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA.|School of Biological Sciences, North West University, Potchefstroom, South Africa.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Klaine
mesh_terms: D033304:Amphipoda / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D010969:Plastics / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D011126:Polypropylenes / Q000737:chemistry; D012098:Reproduction / Q000187:drug effects*; D023382:Toxicity Tests, Acute; D036401:Toxicity Tests, Chronic; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity
chemical_list: D010969:Plastics; D011126:Polypropylenes; D014874:Water Pollutants, Chemical
keywords: Benthic macroinvertebrates; Freshwater toxicology; Microplastics