Vol. 76 (3) 2024

ARTICLES

Microplastic Uptake by Mya arenaria Linnaeus, 1758, Mytilus galloprovincialis Lamarck, 1819 and Cerastoderma glaucum (Bruguière, 1789) (Bivalvia) from Varna Lake, Bulgaria


Svetlana H. Mihova¹,*, Albena V. AleJJxandrova², Valentina G. Doncheva¹, Kremena B. Stefanova¹, Nesho H. Chipev² & Petya P. Ivanova¹

Abstract
Plastic pollution of marine environments has become a global problem. Microplastics have the potential to bioaccumulate in marine biota and ecosystems. Depending on their bioavailability and size, they can be potentially dangerous to the health of organisms and ecosystems. This study aimed to assess microplastics bioaccumulation in bivalve species from the hypereutrophic Varna Lake. Totally, 58 bivalves of three species (Mya arenaria, Mytilus galloprovincialis and Cerastroderma glaucum) were collected from Varna Lake. The most common type of microplastics were fragments (61.54%) followed by fibres (15.38%), microbeads (11.54%), films and sponge/foam. Microplastics were recovered in 60 % of M. galloprovincialis (1.73±2.09 part/ind.), 58 % of M. arenaria (1.77±2.27 part/ind.), and 29 % of C. glaucum (0.35±0.61 part/ind.). The lowest number of microplastics was identified in C. glaucum (0–2 part/ind.) while M. galloprovincialis (0–6 part/ind.) and M. arenaria (0–8 part/ind.) presented almost equal content. The most frequent plastic colour was blue (26.92 %) followed by red (25.64 %), grey (15.38 %), black (12.82 %) and green (10.26 %). Our study reveals the first evaluation of the uptake, level of accumulation, shape, colour and size class of microplastics by three native bivalve species in Varna Lake. Much more research is needed for a more precise assessment of the patterns of bioaccumulation and the effects of microplastics in marine bivalves.

Key words
Bivalves, Black Sea, plastic pollution, mussel, soft-shell clam, cockle