Plastic pollution is a global concern that has a significant impact on marine life. Plastic is widely used and has become a pervasive pollutant in marine environments. Plastic contamination has been documented both in marine environments and biota. Plastic contamination in cetacean gastro-intestinal tract (GIT) content has received limited attention, especially in the Black Sea. This study aims to investigate plastic contamination in the GITs of bottlenose dolphins and harbour porpoises, introducing a novel methodology. Given the limited exploration of this issue in the Black Sea, the research predominantly focuses on microplastic contamination. The GITs were sampled through necropsy from stranded and by-caught cetaceans, and content was washed through a multi-sieves tool. The material retained on each sieve was analysed following specific protocols. All (100%) of the GITs contained plastics (meso- and microplastics). In total, 1059 items (fibres, fragments, and beads) ranging from 22.86 µm to 5776 µm were found, suggesting a high contamination level in the Black Sea cetaceans. Future efforts should concentrate on increasing the number of samples and using the results for the implementation of the Marine Strategy Framework Directive (MSFD).

Microplastics (<5 mm) are an emerging threat to marine ecosystems and organisms, including fish. Recent studies have ranked the Black Sea as one of the most plastic-polluted European seas. Although there is evidence of microplastic ingestion in various fish species in the Black Sea, data for the Romanian sector are still lacking. This study presents the first assessment of microplastic abundance, color, shape, and size in the gastrointestinal tract and gills of Engraulis encrasicolus (European anchovy) collected from different locations along the Romanian coast (NW Black Sea). Ingested plastics were identified using 10% potassium hydroxide (KOH) chemical digestion and analyzed under a stereomicroscope. We observed a high frequency of plastic ingestion, with up to 88% of anchovies containing microplastics (98.5%) and mesoplastics (1.5%), with a mean of 3.03 plastic items/individual, marking the highest reported abundance in the Black Sea. The most common types found were transparent fibers, within the size range of 330 µm–1 mm. Our assessment is the first to demonstrate microplastic contamination in commercial European anchovies from the Romanian coast. Further studies are required to completely understand the extent of microplastic pollution in Black Sea anchovies and its potential impact on both human health and the ecosystem.

Alosa immaculata Bennett, 1835, commonly referred to as the Danube shad, is an anadromous pelagic species of the Clupeidae family, and plays a significant economic role for countries bordering the Black Sea. This study investigates the occurrence of both parasites and microplastics in A. immaculata specimens collected from Sfântu Georghe, with the aim of assessing their potential impact on fish health. The overall physiological condition of the fish was evaluated using Fulton’s condition factor (K) to determine whether the presence of parasites or microplastics had any measurable effect. Five parasitic genera were identified, including one ectoparasitic species from the genus Mazocraes, and four endoparasitic species from the genera Pronoprymna, Lecithaster, Hysterotylacium, and Contracaecum. Microplastic analysis showed a dominance of particles measuring 1–5 mm (62.5%), with fibers and foils being the only morphological forms detected. The most common colors were black (45%), transparent (35%), blue (12.5%), and brown (7.5%). The distribution of microplastics was higher in the stomach than intestines. Our findings offer critical insights into the combined effects of parasitic infection and microplastic pollution on this key Black Sea species. The integrated methodology, combining parasite load, microplastic content, and condition factor analysis, marks a novel approach in fish health assessment.

Microplastics (<5 mm) have become a pervasive pollutant because of their persistence, bioavailability, and risk of trophic transfer. The present work provides new evidence on microplastic contamination in three economically important species from the Romanian Black Sea coast: Mytilus galloprovincialis, Rapana venosa, and Sprattus sprattus. Microplastics were extracted using 10% potassium hydroxide (KOH) chemical digestion and examined under a stereomicroscope. Microplastics frequency of occurrence (FO%) ranged from 66.7% to 93.3%, with mean abundances per individual being 3.06 ± 3.71 in mussels, 3.26 ± 2.08 in rapa whelks, and 3.13 ± 2.44 in sprats. Fibers were the dominant type, followed by fragments, with blue, black, and transparent colours most common. Most particles were within the 1–5 mm and 330 µm⁻¹ mm size classes, with smaller fractions between 100 and 330 µm, indicating ingestion of particles large enough to accumulate rather than be rapidly egested. The microplastic contamination found in predatory R. venosa suggests trophic transfer of microplastics from bivalve prey. As all three species are consumed by humans, they represent potential pathways for microplastic exposure. These results emphasize the urgent necessity for additional research on sources, environmental pathways, and possible health risks of microplastics in the Black Sea.

The pontic shad (Alosa immaculata Bennett, 1835), one of the most economically and ecologically important species for the Danube–Black Sea basin, is affected by a large variety of anthropic and biological pressures. In this study, we aimed to investigate the presence of microplastics, persistent organic pollutants (POPs), polycyclic aromatic hydrocarbons (PAHs), and endoparasites alongside biological condition indices on individuals collected from Chișcani locality from the lower Danube Romanian sector. The overall abundance of microplastics was 1.36 ± 1.8 SD particles per individual, with significant differences between the gastrointestinal tract (1.33 ± 1.32 SD microplastics/ individual) and muscular tissue (0.23 ± 0.62 SD microplastics/ individual). The median concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were 0.560 μg/g and 0.576 μg/g, respectively, with hexachlorobenzene, heptachlor, and lindane predominating among the OCPs, while phenanthrene and naphthalene were predominant for the PAHs. The parasitological analysis identified four species of endoparasites, with Hysterothylacium sp. being the predominant genus, showing the highest prevalence, mean intensity of infestation, and abundance. No significant associations with morphometric traits or condition indices were found. Our findings document the co-occurrence of microplastics, organic contaminants, and parasites in the examined A. immaculata specimens, highlighting the need for long-term, integrated monitoring of this ecologically and economically significant species.