Vol. 78 2026

ARTICLES

Microplastic Bioaccumulation in Mollusks from Sozopol Bay (Black Sea, Bulgaria): A Comparative Assessment

Albena Alexandrova1,*, Nesho Chipev1, & Lyubomir Kenderov2

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*,1Laboratory of Free Radical Processes, Institute of Neurobiology, Bulgarian Academy of Sciences, 23, Acad. Georgi Bonchev, str., 1113 Sofia, Bulgaria; E-mail: a_alexandrova_bas@yahoo.com, nchipev@abv.bg
2Department of General and Applied Hydrobiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria; E-mail: lubomir.kenderov@biofac.uni-sofia.bg

https://doi.org/10.71424/azb78.1.003014

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Abstract

Plastic pollution is an increasing threat to marine ecosystems, with microplastics (MPs) posing particular concern due to their potential to harm marine organisms and disrupt ecological balance. Understanding the extent and nature of MPs contamination in bivalves is crucial for identifying effective bioindicators, supporting ecological risk assessments, and guiding monitoring. This study aimed to comparatively analyze the accumulation, composition, and characteristics of MPs in two bivalve species, Mytilus galloprovincialis Lamarck, 1819, and Magallana gigas (Thunberg, 1793), collected from Sozopol Bay (Bulgarian Black Sea southern coast), evaluating their suitability as bioindicators of MPs pollution and associated health and ecological risks. Specimens were collected via scuba diving, and MPs’ presence in soft tissues was examined using the Agilent 8700 LDIR Chemical Imaging System. MPs were detected in 86% of the analyzed individuals, with significantly higher concentrations in oysters than in mussels (8.92 vs. 0.18 MPs/gram of soft tissue). Polyethylene terephthalate was the dominant polymer in M. galloprovincialis (44%), while polyethylene was most prevalent in M. gigas (56%). The majority of MPs measured were in the range 20–50 µm. Most particles were irregular or rounded fragments. These findings confirm substantial MPs contamination in Sozopol Bay and suggest that M. galloprovincialis is a more reliable early-warning indicator for MPs presence, while M. gigas provides comprehensive information about the presence and types of MPs. Their combined use in biomonitoring programs could enhance the accuracy and resolution of MPs’ assessments.

Key words

bivalves, Black Sea, ecological risk, microplastics

How to Cite
Alexandrova A., Chipev N., & Kenderov L. 2026. Microplastic Bioaccumulation in Mollusks from Sozopol Bay (Black Sea, Bulgaria): A Comparative Assessment. Acta zoologica bulgarica 78.

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