Microplastics (MPs) have adverse effects on aquatic organisms in marine environments; however, there is a lack of information on freshwater environments. This study investigated the dietary uptake, and biodistribution and depuration of MPs in the freshwater diving beetle Cybister japonicus (Coleoptera: Dytiscidae) after consumption of zebrafish (Danio rerio) exposed to MPs. The transfer of MPs in diving beetles after consumption of zebrafish was assessed to determine whether the presence of MPs affected diving beetle behavior and predation. We found that diving beetles that consumed MP-exposed fish had a significantly lower ingestion rate than the control. In addition, the trophic transfer rate of MPs was 13–18%. However, MPs were found only in the crop and proventriculus of the beetles, and all particles were depurated within 48 h, likely via regurgitation. As diving beetle is a top predator in freshwater ecosystems and could facilitate transfer from aquatic to terrestrial ecosystems via predation, its behavior towards indigestible MPs in its digestive organs (i.e., filtering and vomiting) could represent a meaningful phenomenon as a potential vector for MP transport. This is the first report of the trophic transfer of MPs from fish to dytiscid species, which helps clarify the effects and mechanisms of MPs in freshwater systems.

Millions of tons of plastic enter the environment every year, where much of it concentrates in environmental sinks such as tidal marshes. With prior studies documenting harm to marine fauna caused by this plastic pollution, the need to understand how this novel type of pollution affects estuarine fauna is great. Yet, research on the fate and uptake of plastic pollutants in estuarine ecosystems is sparse. Therefore, we quantified plastic prevalence and ingestion by two species of resident marsh bird, Clapper Rails (Rallus crepitans) and Seaside Sparrows (Ammospiza maritima), in coastal marsh ecosystems within Mississippi. We detected microplastics (plastics smaller than 5 mm) in 64% of marsh sediment samples, 83% of Clapper Rail and 69% of Seaside Sparrow proventriculus samples. Dominant types of microplastics detected in sediment and bird samples were fibers. This study provides the first evidence of microplastic ingestion by marsh birds and its distribution in coastal marshes within Mississippi.

This study provides the first quantification of plastic ingestion in the Tristram's Storm-petrel (Oceanodroma tristrami) in over 20 years. We found 100% plastic incidence in 57 chicks collected opportunistically over four breeding seasons (2007, 2010, 2011, 2012), with the mass of ingested plastic per individual ranging from 0.1 to 2.8 g (≤3.3% adult mass). While plastic occurred in every bird we examined, the proventriculus contained significantly more plastic, more fragments, and larger fragments than the gizzard. Most of the ingested plastic (97.5% by mass) consisted of fragments, ranging in length from 0.4 to 11.6 mm and ranging in surface area from 0.07 to 45.21 mm2. While fragments were ubiquitous, occurring in every proventriculus and gizzard we analyzed, Tristram's Storm-petrels also ingested foam, line and sheets. Digital analysis of 1425 ingested plastic fragments documented a wide range of colors, involving shades of white, yellow, orange, red, blue, green, and black.

Between 2006 and 2013, we salvaged and necropsied 362 seabird specimens from Tern Island, French Frigate Shoals, Northwestern Hawaiian Islands. Plastic ingestion occurred in 11 of the 16 species sampled (68.75%), representing four orders, seven families, and five foraging guilds: four plunge-divers, two albatrosses, two nocturnal-foraging petrels, two tuna-birds, and one frigatebird. Moreover, we documented the first instance of ingestion in a previously unstudied species: the Brown Booby. Plastic prevalence (percent occurrence) ranged from 0% to 100%, with no significant differences across foraging guilds. However, occurrence was significantly higher in chicks versus adult conspecifics in the Black-footed Albatross, one of the three species where multiple age classes were sampled. While seabirds ingested a variety of plastic (foam, line, sheets), fragments were the most common and numerous type. In albatrosses and storm-petrels, the plastic occurrence in the two stomach chambers (the proventriculus and the ventriculus) was not significantly different.