Microplastic characteristics in organisms of different trophic levels from Liaohe Estuary, China

Microplastics are a growing concern globally due to their small size and easy ingestion by terrestrial and aquatic organisms, resulting in potential adverse impacts on wildlife. However, current data regarding microplastics in wild organisms in different trophic levels is limited. This study investigated microplastic characteristics, including their abundance, size, shape and polymer type, in estuarine invertebrates and vertebrates. Resultantly, polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) were the predominant microplastics found, as confirmed by a Fourier transform infrared spectrometer (FT-IR). An average microplastic abundance of 0.83 +/- 0.99 to 3.87 +/- 2.18 items/individual was detected across all species, including sandworm, mollusks, crustacean and fish, but they were not found in all individuals. Microplastics ranged from 52 mu m to 5392 mu m in size, and the shapes were consisted of fiber, fragment, and pellet. Moreover, the detection ratio (91.95%) and abundance (3.34 +/- 2.17 items/individual) of microplastics in fish were significantly higher than in sandworm (42.86%, 0.88 +/- 1.04 items/individual), mollusks (66.97%, 1.42 +/- 1.41 items/individual) and crustaceans (66.66%, 1.33 +/- 1.32 items/individual) (p < 0.05). Furthermore, a positive relationship was identified between microplastic abundance and the trophic level of organisms. These findings imply that microplastics might transfer along the food chain and accumulate at organisms in higher trophic levels. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the characteristics of microplastics in estuarine invertebrates and vertebrates, finding that polyethylene, polypropylene, and polyethylene terephthalate were the predominant types. The study also revealed that fish had significantly higher detection rates and abundance of microplastics compared to other species, and a positive relationship was found between microplastic abundance and the trophic level of organisms, suggesting potential transfer along the food chain and accumulation at higher trophic levels.