Size‐ and shape‐dependent effects of microplastic particles on adult daggerblade grass shrimp (Palaemonetes pugio)

Abstract

The incidence of microplastics in marine environments has been increasing over the past several decades. The objective of the present study was to characterize the size- and shape-dependent effects of microplastic particles (spheres, fibers, and fragments) on the adult daggerblade grass shrimp (Palaemonetes pugio). Grass shrimp were exposed to 11 sizes of plastic: spheres (30, 35, 59, 75, 83, 116, and 165 μm), fragments (34 and 93 μm), and fibers (34 and 93 μm) at a concentration of 2000 particles/400 mL (= 50 000 particles/L) for 3 h. Following exposure, grass shrimp were monitored for survival, ingested and ventilated microplastics, and residence time. Mortality ranged from 0% to 55%. Spheres and fragments <50 μm were not acutely toxic. Mortality rates in experiments with spheres and fragments >50 μm ranged from 5% to 40%. Mortality was significantly higher in the exposure to 93-μm fibers than other sizes tested (p < 0.001). The shape of the particle had a significant influence on the number of particles ingested by the shrimp (p < 0.001). The residence time of particles in the gut ranged from 27 to 75 h, with an average of 43.0 ± 13.8 h. Within the gills, the residence time ranged from 27 to 45 h, with an average of 36.9 ± 5.4 h. The results suggest that microplastic particles of various sizes and shapes can be ingested and ventilated by adult daggerblade grass shrimp, resulting in acute toxicity. Environ Toxicol Chem 2017;36:3074-3080. © 2017 SETAC.

The Effect of Microplastic Ingestion on Survival of the Grass Shrimp Palaemonetes pugio (Holthuis, 1949) Challenged with Vibrio campbellii

“…As a result, grass shrimp were able to depurate the majority of ingested particles during the 48‐h period in particle‐free water (Figure ). These results are consistent with those of Gray and Weinstein (), who determined that the average residence time for microplastics in the digestive tract and gills of grass shrimp was 43.0 ± 13.8 and 36.9 ± 5.4 h, respectively. The ability of grass shrimp to depurate these particles likely limited the physical toxicity of the particles (Wright et al ).…”

“…Despite the absence of mortalities or immunotoxicity in the present 96‐h exposure study, the number of particles present in the shrimp gut ranged from 0 to 208 particles/individual (Figure ) and in the gills ranged from 0 to 5 particles/individual (Figure ). In contrast, Gray and Weinstein () reported much lower uptake of particles in the gut and gills of grass shrimp following a 3‐h, 50 000 particles/L exposure to polyethylene spheres, polystyrene spheres, polypropylene fragments, or weathered polypropylene fibers in the same size range used for our study, but nonetheless documented mortalities from the microplastic exposure. These results highlight the variability in the number of ingested and ventilated particles/shrimp and suggest that the accumulation of particles in the gut of grass shrimp increases with exposure time.…”

“…Whereas Gray and Weinstein () and Au et al () demonstrated the toxicity of weathered polypropylene fibers, Jemec et al () demonstrated the toxicity of pristine polyester fibers similar to the fibers used in the present study. Jemec et al () determined that pristine polyester fibers (62–1400 µm length, 31–528 µm width, 1–21.5 µm thickness) were toxic to Daphnia magna following 48‐h exposure to a concentration of 12.5 to 100 mg/L (minimum 5.2–41.6 × 10 3 particles/L).…”

“…Aqueous 96‐h static exposures were conducted for each particle type at a nominal concentration of 50 000 particles/L in settled seawater from Charleston Harbor, a dose previously shown to be acutely toxic to grass shrimp (Gray and Weinstein ). The present study utilized this exposure concentration to remain consistent with the methods previously reported for acute microplastic toxicity assays with grass shrimp (Gray and Weinstein ). Grass shrimp were exposed to particles in 4‐L glass jars with 2 L of test solution.…”

Microplastics: What Drinking Water Utilities Need to Know

“…A study of Northern Fulmar seabirds off the coast of Norway showed that levels of hazardous organic pollutants in the birds had no correlation to the amount of plastic in their stomachs (Burton ). Another study by Gray and Weinstein () showed that the toxicity depended on the size and shape of microplastics. Spheres and fragments smaller than 50 μm had no acute effects but were acutely toxic at larger sizes, as were fibers at 93 μm (Burton ).…”