Bivalvia, Linnaeus, 1758

3.1.3.2. Bivalvia View in CoL

Bivalves include filter-feeding oysters, mussels, and clams. These organisms have been used as bioindicators to determine aquatic pollution due to their sensitivity to biotic and abiotic changes. Therefore, the sensitivity of bivalves to MPs has also been of interest and extensively studied. Some studies argue that bivalves can be used as bioindicators in determining MP pollution (Wakkaf et al., 2020; Patterson et al., 2021; Truchet et al., 2021; Wootton et al., 2022) and vice versa (Ward et al., 2019). They are also an economically important group with high consumption as seafood worldwide. Given that bivalves are consumed whole without internal organs, directly transferring their accumulated substances (Shumway et al., 2023), studying the MP concentrations in bivalves is important.

The MP concentrations and types in oysters, mussels, and clams, which are widely used as food, have been investigated in many studies. In this review, data from 19 bivalve species from 19 studies were analyzed. Researchers have primarily extracted MPs from the soft tissues of bivalves using 10% KOH. Fibers and fragments are the most common forms of these MPs. ATR-FTIR and µFTIR were predominantly used to determine polymer types. The most common polymer types were PE, PP, and PET. The Mediterranean mussel Mytilus galloprovincialis is the most studied species, with mean MP levels varying across different regions, from 0.5 MPs/individual on the shores of İstanbul ( Galyon and Alçay, 2023) to 18.6 ± 23.0 MPs/ individual on the Catalan coast ( Expósito et al., 2022). These researchers estimated that daily consumption of mussels could lead to an intake of 42.8 MPs/day for adults.

The minimum MP concentration was recorded in the mussel M. galloprovincialis as 0.5 MPs/individual on the shores of İstanbul, Türkiye ( Galyon and Alçay, 2023). The maximum MP concentration (25.3 ± 32.6 MPs/individual) was found in the mussel Brachidontes pharaonis on the Red Sea coast of Egypt ( Abd-Elkader et al., 2023).