'Microplastic (MP) pollution has emerged as a persistent environmental concern for marine ecosystems. Toxicity risk depending on MP ingestion is an important health concern for both marine organisms and humans due to their connection via food web. So far, majority of the studies have investigated MP abundance in the commercial fish species leaving the commercial cephalopods ignored. To fill this gap, occurrence and distribution of MPs in the organs of commercially important cephalopod species Loligo vulgaris and Sepia officinalis were investigated for the first time in Northeastern Mediterranean Sea. MPs were detected in more than 80 % of examined specimens. The pooled average abundance of MP was found as 2.1 f 1.8 MPs per individual, 1.5 f 1.7 MPs per g wet weight (ww) in gastrointestinal tract (GIT) and 1.6 f 1.4 MPs per individual, 2.5 f 3.8 MPs per g ww in gills. Dominant characteristics of isolated MPs were fiber shape, blue color and size of less than 1 mm. Polymer distribution was found as polyethylene (34 %), polypropylene (25 %), high-density polyethylene (17 %), polystyrene (13 %) and polyvinyl chloride (11 %). The prevalence of small-sized MPs could potentially facilitate translocation into edible tissues (e.g., the mantle). While not directly measured in this study, such a pathway is supported by literature and warrants further investigation regarding associated health risk concerns. This study provides baseline data which brightens the MP pollution levels in cephalopods that can be used as information for upcoming mitigation strategies and legislations. Since this study provides preliminary data from a single location and season, future research is required to investigate how ecological and biological factors-such as habitat, feeding habits, morphological parameters, maturity, and regional hydrodynamic properties-influence MP ingestion.

Microplastic (MP) pollution has emerged as a major environmental concern in marine ecosystems, yet the ecological mechanisms governing MP ingestion in fish assemblages remain insufficiently quantified. This study investigated the relative influence of habitat preference, feeding behavior, trophic level, and biological traits on MP ingestion in 11 fish species (N = 297) collected from the highly industrialized Iskenderun Bay, Northeastern Mediterranean Sea. Because MP abundance data exhibited substantial overdispersion, both Poisson and Negative Binomial Generalized Linear Models (GLMs) were evaluated, with the Negative Binomial framework demonstrating markedly superior performance based on the akaike information criterion (AIC) and dispersion diagnostics. The final model identified habitat-related exposure pathways as the dominant predictors of MP ingestion. Relative to the benthopelagic reference group, demersal species exhibited significantly higher expected MP abundance (β = 0.99, p < 0.001), whereas pelagic-neritic species showed significantly lower MP loads (β = − 1.13, p < 0.001). Gastrointestinal tract (GIT) weight was positively associated with MP abundance (β = 0.16, p < 0.001), suggesting that anatomical retention capacity may influence particle accumulation. In contrast to conventional biomagnification expectations, the trophic level displayed a significant negative relationship with MP abundance (β = − 0.47, p = 0.0047), indicating a potential trophic dilution pattern. Residual diagnostics performed using the DHARMa framework indicated satisfactory model adequacy, while zero-inflated models did not substantially improve model performance. The findings suggest that habitat-mediated exposure, particularly sediment-associated pathways, may exert stronger influence on MP ingestion than feeding behavior alone. Overall, this study highlights the importance of combining ecological trait analysis with robust statistical modeling approaches to understand MP uptake dynamics in Mediterranean fish communities.

Microplastic (MP) pollution levels in aquatic environments raise concerns regarding the potential harm to biota and the environment. Mussel species are categorized as perfect bioindicator of pollutants due to their sessile lifestyle, and filter-feeding activity that also make them more prone to microplastic contamination. This study was designed to assess microplastic pollution levels in the soft tissues of dominant freshwater mussel species to understand general picture in microplastic contamination of the ambient environment. For that purpose, microplastic presence in the soft tissue of Unio delicatus (n:49), Unio Terminalis (n:31) and Dreissena polymorpha (n:82) was investigated. Including all examined specimens, mean microplastic abundance was found as 0.6 ± 0.8 items/ind, 0.2 ± 0.5 items/g ww with occurrence rate of 48 %. Reflecting global distribution, general morphological characteristics of MPs were fiber shape, blue colored and less than 500 μm in size. Fourier transform infrared (FTIR) spectroscopy identified the polymer type of MPs as polyethylene (40 %), polypropylene (47 %), and polystyrene (27 %). The results obtained in this study provide baseline information regarding microplastic contamination in freshwater environments and emphasize the need of protective measures.

It is known that aquatic environments become the ultimate sink of emerging contaminants, namely microplastics (MPs). This review focused on exploring the current situation of microplastic presence in aquaculture facilities and aquaculture animals together with potential sources. A total of 90 peer-reviewed publications available on Web of Science were considered in the systematic review. Results revealed the important role of anthropogenic influences near the aquaculture facilities together with internal factors (such as infrastructure, feed, animal behavior etc). Literature results showed significant variation in microplastic abundance depend taxa; however,, no variation was observed depending on natural feeding preference or habitat of the species. Obtained data proved the widespread presence of microplastics in aquaculture animals that form a potential microplastic intake pathway for humans. This condition trigger microplastic accumulation in human body that might cause decrease in immune system or local particle toxicity. Therefore, necessary legislations should be implemented to sustain economic growth of the industry while reducing concerns regarding consumption of aquaculture products.

Microplastics (MPs) are ubiquitous pollutants in marine environment and monitoring studies have been conducted to understand microplastic presence in aquatic biota. However, studies addressing the microplastic abundance in invertible species are scant. This study aims to investigate presence of ingested microplastics in three commercial shrimp species (Metapenaeus monoceros, Plesionika martia and Melicertus hathor). Mean microplastic abundance (with standard error) in the digestive organs was found as 0.76 ± 1.0 MPs/ind and 0.86 ± 1.5 MPs/g wet weight. No significant difference was detected between species. Fiber (87 %), black (53 %), <500 μm (62 %) microplastic particles was dominant. A negative correlation was found between shrimp weight and ingested microplastic amount (r:-0.46, p:0.005). FTIR analysis showed polyethylene (PE) and polypropylene (PP) as identified polymers. Results proved microplastic exposure in shrimp species from İskenderun Bay and average of 14 to 441 MPs per year could be transferred to human body upon consumption. Therefore, study results showed the microplastic exposure risk depending on consumption of crustacean species and underlined the need of protective measures.

Freshwater environments are a significant source of microplastics in the oceans, but, little is known about the distribution of microplastics in rivers and lakes. This study was undertaken to investigate the abundance and composition of microplastics (MPs) in the surface water and sediment of Karasu Creek, Gölbaşı Lake and Orontes River which are critical habitats for many endangered species. The mean microplastic abundance in the surface water and sediment of the Orontes Basin was determined to be 3.2 ± 4.0 MPs/L and 456 ± 318 MPs/kg, respectively. Due to the similar socioeconomic status and anthropogenic activities in the vicinity of stations, there wasn't any temporal variation in the microplastic abundance depending on stations. However, microplastic abundance in the surface water was drastically increased during flood periods. A correlation between microplastic abundance in the surface water and sediment was not detected due to insufficient data representing the hydrodynamic properties of the study area. Morphologically, fiber MPs were dominant (89 %), followed by fragments (9 %). The majority of the extracted MPs were <1 mm. This led to an increase in the number of individuals and species likely to be negatively affected by MPs. In terms of color, majority of the MPs were black (44 %) followed by blue (21 %), red (18 %), transparent and white (9 %). Results obtained in this study proved the ubiquity and dominance of the microplastics in both surface water and sediment. Therefore, the findings clearly show a remarkable ecological risk and indicate the need for mitigation strategies in the Orontes Basin ecosystem.This study provided critical data for local and national authorities to take necessary precautions to manage microplastic pollution in the Orontes Basin. However, more comprehensive understanding of the long-term impacts of pollution from MPs on endemic species is crucial for effective conservation strategies.

This study is the first report evaluating the microplastic (MP) and macroplastics capture potential of Pontederia crassipes. Total of 3691 (508 microplastic and 3183 macroplastic) particles were extracted from the roots of 12 examined specimens. Mean macroplastic abundance in the roots was found as 265±44 macroplastic/specimen. Majority of the extracted macroplastics were fragment in shape, blue in color. Mean microplastic abundance was found as 42±23 MPs/specimen. Majority of the extracted microplastics were fragment in shape, blue in color and less than 500 μm in size. Results of this preliminary study showed that this species have significant ability to adsorb micro and macroplastics by the roots which makes them perfect employees for integrated floating systems.

This study is first study reporting the microplastic abundance in soft tissues of a bivalvae Brachidontes pharaonis collected from 4 stations of İskenderun Bay. A total of 245 B. pharaonis specimens were examined and results showed that among examined specimens, 95 of them contained microplastic in their soft tissues. When all the data combined, mean MP abundance was found as 0.4±0.5 MPs ind-1 and 0.3±0.4 MPs g-1 ww. Fibers were predominant type of MPs and accounted for 75% of total extracted MPs, followed by fragments (25%). Majority of MPs were less than 1 mm and black. Fourier transform infrared spectroscopy (FTIR) showed that the extracted MPs were polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). Identified polymer types indicate that aquatic biota impacted by the anthropogenic influences such as agriculture, farming, fishing, household, etc. Results obtained in this study contribute the knowledge related with the microplastic contamination levels in marine biota.

Wastewater treatment plants (WWTPs) are the last stop for microplastic particles generated by anthropogenic activities before they enter the aquatic environment. In this study, three WWTPs discharging into Orontes River were investigated in terms of microplastic (MP) composition, microplastic abundance, treatment and load. Two of the WWTPs apply secondary treatment with activated sludge system and trickling filter, whereas the last WWTP apply tertiary treatment with a membrane bioreactor. When all data are combined, mean MPs abundance in the influent and effluent samples were found as 57.2 MPs/L and 2.1 MPs/L, respectively. The highest MPs removal was achieved by the membrane bioreactor (99

Microplastic pollution in snow was investigated in top of the Amanos Mountain in Hatay region, southern Turkey. Snow samples were collected from four stations located in different heights and fronts of the mountain. Abundance of microplastic ranged from 10.5 to 16 MP per liter and a total of 519 microplastic particles (MPs) were identified in snow samples. The majority of identified microplastic were fiber (>99%), black in color and 0.5 – 2.5 mm (62%) size class and polyester (35%). This is the first study examining the microplastic pollution in snow from Turkey. Local wind and trajectory analyses revealed that MPs appeared in the sampling region originated from closely located Amik Plain and/or were transported from remote areas with northwesterly and southerly airflows.

This study reports first evidence of microplastic detection in the Patella caerulea collected from 5 different sta-tions located in Iskenderun Bay and Mersin Bay. A total of 160 P. caerulea specimens were examined and 40 of them contained MPs in their soft tissues. The number of microplastics extracted per sample varied from 0.20 +/- 0.5 items/ind to 0.45 +/- 0.7 items/ind depending on station. Fibers were predominant type of MPs and accounted for 75 % to 87.5 % of total extracted MPs, followed by fragments (12.5-25 %). Majority of MPs were 0.5-1 mm size and black in color. Fourier transform infrared spectroscopy (FTIR) showed that the extracted MPs were polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET), high density polyethylene (HDPE). This study contributes to the knowledge of the transfer of microplastics to the marine food web and highlights the need for protective measurements.

Microplastic pollution in snow was investigated in top of the Amanos Mountain in Hatay region, southern Turkey. Snow samples were collected from four stations located in different heights and fronts of the mountain. Abundance of microplastic ranged from 10.5 to 16 MP per liter and a total of 519 microplastic particles (MPs) were identified in snow samples. The majority of identified microplastic were fiber (>99%), black in color and 0.5 – 2.5 mm (62%) size class and polyester (35%). This is the first study examining the microplastic pollution in snow from Turkey. Local wind and trajectory analyses revealed that MPs appeared in the sampling region originated from closely located Amik Plain and/or were transported from remote areas with northwesterly and southerly airflows.

Microplastic pollution is an extremely emerging problem and its potential threats to the aquatic organisms were investigated worldwide. In this study, four different commercial fish species (Mullus barbatus (Linnaeus, 1758), Mullus surmuletus (Linnaeus, 1758), Mugil cephalus (Linnaeus, 1758), Saurida undosquamis (Richardson, 1848)) were used as a bioindicator to assess the microplastic pollution in the northeastern Mediterranean. The frequency of occurrence in the gastrointestinal tract (GIT) and gill was varied between 66-100% and 68-90%, respectively. The highest microplastic abundance was detected at the GIT of M. cephalus sampled from Asi River estuary. The majority of extracted microplastics were fiber, black in color and less than 1 mm in size. Fourier Transform Infrared Spectroscopy (FTIR) indicated the most common polymer type as polyethylene. This study is the first study examining the microplastic existence in gill and results obtained in this study improve the knowledge about the relationship of microplastic ingestion in fish and environmental conditions in the Northeastern Mediterranean Sea.

This study provides the first evidence of microplastic (MP) occurrence in gill and gastrointestinal tract (GIT) of Pontastacus leptodactylus (N = 37), a commercially important crayfish in Turkey. MPs were found in the GIT of all examined individuals with an average of about 11.9 +/- 9.7 (male: 13.6 +/- 8.3 and female: 10.1 +/- 10.9) MPs/ind. Female crayfishes ingested less MPs than males potentially due to being more sedentary as well as interruption in feeding during spawning and hatching periods. The concurrencies of tangled balls of fibers were detected as 47 % in males and 28 % in females. The majority of extracted microplastic were fiber (97 %), black (56 % in the gill and 38 % in the GIT) and 1-2.5 mm in size (35 % in the gill and 39 % in the GIT). High MPs contamination observed in this study highlights the concerns related to the consumption of seafood since Pontastacus leptodactylus is commercially used.

Risso's dolphin Grampus griseus was stranded on the coast of Arsuz-Uluçınar, Iskenderun Bay, Turkey in the northeastern Mediterranean on 29 March 2022. This study was conducted to reveal the relationship between G. griseus and microplastic debris in the northeastern Mediterranean Sea. The gastrointestinal tract (GIT) of one stranding G. griseus was examined, and 454 microplastics particles were extracted. Of all, the majority of them were fibers (96%), black in colour (62%), and 0.5-1 mm in size (38%). This paper represents the first data indicating the microplastic abundance in G. griseus from the northeastern Mediterranean Sea. Also, it creates a baseline to understand the relationship between cetaceans and microplastics in this region.

Freshwater environments are more sensitive to anthropogenic influences and usually contain higher concentrations of pollutants than marine environments. Microplastic pollution causes additional stress on freshwater animals; yet, studies evaluating the microplastic occurrence in freshwater biota are still limited. In this study, microplastic occurrence in the gastrointestinal tracts (GIT) and gill of commercial fish species (Prussian carp Carassius gibelio (Bloch, 1782); Abu mullet Planiliza abu (Heckel, 1843); Common carp Cyprinus carpio Linnaeus, 1758; European ell Anguilla Anguilla (Linnaeus, 1758); North African catfish Clarias gariepinus (Burchell, 1822); Goldfish Carassius auratus (Linnaeus, 1758) were reported from Orontes River. MPs abundance in the GIT and gill of six species were found as 5.1 +/- 2 MPs fish-1 and 4.4 +/- 2 MPs fish-1 with an occurrence of 95% and 74%, respectively. The majority of extracted microplastics were fiber, black and less than 1000 mu m in size. FTIR analysis determined the main polymer types as polyester (50%), high-density polyethylene (HDPE) (10%), polypropylene (PP) (8%) and polyethylene terephthalate (PET) (5%). High MPs abundance and frequency of occurence indicate the exposure of microplastic pollution in freshwater biota which could threat the health of both individuals and consumers. Results obtained in this study will increase the acknowledgement of MPs pollution in the Orontes River. Also, this study will provide data to the administrators to set up necessary legislations in freshwater ecosystems.

Microplastic (MP) pollution in marine environments has been a major global concern in recent years. Microplastic particles pose a threat in aquatic animals by accumulating in their digestive system, acting like a pollution vector, and they can also transfer to upper trophic levels. For that reason, commercially important deep-water rose shrimp Parapenaeus longirostris were employed in this study to examine the MP pollution status of two different regions (Samandağ and Mersin offshore waters) of the northeastern Mediterranean Sea. MPs were detected in all examined specimens (average of 18.8 MPs ind−1), and fiber tangle-shaped like balls were observed by 22

Nowadays, the majority of marine debris consists of microplastic particles. For that reason, microplastic pollution in marine environments and its potential impacts on marine animals has been extensively studied. This study was developed to investigate the bioindicator potential of Pterois miles (Bennett, 1828) for the monitoring of microplastic pollution. A totally, 21 individuals were sampled from Iskenderun Bay, northeastern Mediterranean Sea on April 2022, and their gastrointestinal tracts were examined for microplastic occurrence. Mean microplastic abundance was found as 2.06±1.88 particles/individual in positive samples and 1.47±1.83 particles/individual in total samples. The microplastic detection rate was estimated as 71%. In terms of color, black (55%), blue (32%), red (10%) and brown (3%) microplastic particles were detected. Among all, the majority of the extracted particles were fiber in shape (93%) and followed by fragments (7%). The high frequency of detection and microplastic abundance estimated in this study showed that this specie could be used to monitor microplastic pollution in marine environments.

Even though North-Eastern Mediterranean (NE Med) is classified as oligotrophic, inshore areas are highly eutrophic due to the discharge of silicate and nitrate-rich surface waters. Aim of this study was to investigate the nutrient load coming from the Göksu River and to estimate its impact on the river domain using satellite images. Monthly, average nitrite (NO2), nitrate (NO3), ammonium (NH4) and phosphate (PO4) load found to be varying between 0.07-31.2 ton/month, 15-1226 ton/month, 0.5-539 ton/month, 1-267 ton/month, respectively. Satellite images showed that surface chlorophyll–a (chl-a) in the river downstream had an increase in both winter and spring seasons as a result of intense precipitation; while, primary production at the offshore regions was mainly impacted by winter mixing and summer stratification. The highest chl-a concentration was observed at the river impacted zone and decreased by more than two folds at the offshore regions. Increased NO3 load observed during winter and spring leads to phytoplankton blooms in the river downstream. The high P content of Göksu River surface waters has increased the productivity at all seasons. As a consequence, correlation analysis showed significant relationship between surface chl-a concentration and PO4-NO3 load.

Primary productivity mostly relies on marine cyanobacteria in the oligotrophic north-eastern Mediterranean (NEM). However, wide shelf basin is fed by nutrient-rich rivers (namely GOksu, Lamas. Seyhan, Ceyhan, Asi) leading to apparent increase in algal production at coastal regions. In the present study, variation of picophytoplankton (pico-eukaryotes, Synechococcus and Prochlorococcus) abundance of at different trophic levels of NEM were investigated. Sample collection was carried out at 50 different stations including Mersin Bay, GOksu River discharge area and oligotrophic offshore waters during October 2017, February, April and July 2018. Minimum and maximum abundance of picoeukaryotes, Synechococcus and Prochlorococcus were found as 1-1x10(4), 10(3) - 3.3x10(4) and 8x10(1) 7.3x10(4) cell/ml, respectively. Eukaryotic picoplankton are observed mainly in GOksu River discharge area and could not compete with marine cyanobacteria in offshore waters. Annual average of pico-eukaryotes abundance was decreased by 1.4 folds from inshore to offshore; while, annual average of Synechococcus abundance was increased by 1.2 folds. Prochlorococcus abundance did not vary from inshore to offshore but decreased by 4 folds from river discharge area to offshore area. Synechococcus and Prochlorococcus have displayed similar abundance profiles with peak levels near the Deep Chlorophyll Maximum (DCM) in October and July. Results showed that Synechococcus was the most abundant regardless of location or season. Even though Synechococcus abundance was found to be higher than Prochlorococcus abundance, a significant increase in the contribution of Prochlorococcus to the total picophytoplankton was observed in July.