Does the feeding mechanism determine the accumulation of microplastics in marine benthic organisms? A systematic review

Microplastics are found in all oceanic environments and represent a growing concern for researchers and managers of marine environments. A systematic review was carried out to investigate the accumulation of microplastics (MPs) in filter feeders, focusing on the potential relationship between the feeding mechanism and MPs’ accumulation. The accumulation of microplastics was compared among marine benthic filter feeders that use different filtering mechanisms. Rayyan® software was employed to screen the articles, and data extraction was subsequently carried out. The review followed well-structured protocol PRISMA 2020 guidelines to guarantee methodological rigor and minimize biases. Due to the high heterogeneity (Higgins I 2 test, I 2 > 95%) of data methodologies, a narrative synthesis was used as the output of the review. Most publications report microplastics in mollusks (oysters, mussels, and clams), and bivalves were the group most studied (76.67%). Sponges (91 to 612 items g – 1 DW) and polychaetes (1 to 880 items g–1 WW) had the highest number of MPs. Although it is possible to establish relationships between feeding mechanisms and MPs accumulation, using distinct methodologies makes comparing the results of different studies difficult, leading to an urgent call for standardizing methods for microplastic studies in marine organisms.