A new record for the presence of microplastics in dominant fish species of the Karasu River Erzurum, Turkey

Eukaryotic phototrophs of the plastisphere in the Southeastern Black Sea

Plastics, as artificial substrates in water, are rapidly colonized by microorganisms, forming the plastisphere. Eukaryotic phototrophs of the plastisphere were studied on 46 seafloor plastic samples, representing 11 polymer types, in the Southeast Black Sea during March and July 2022. The plastisphere included 55 species from Heterokontophyta phylum (incl. Coscinodiscophycea (4), Mediophyceae (3), Bacillariophyceae (45), Dictyophyceae (1)), and Haptophyta (1). Common species were Bacillaria paxillifera, Tabularia parva, Cocconeis scutellum, and Licmophora flabellata. Octactis speculum and Emiliana huxleyi were newly reported for the plastisphere, and Thalassiosira curviseriata was recorded for the first time in the Black Sea. Two potentially harmful algae and five bloom-forming species were identified. Shannon Diversity Index values ranged from 0 to 2.9, with the highest diversity on PE/PVA and PES samples and the lowest on PE. Habitat preferences showed 34 species associated with plankton-benthic or benthic microalgae. PERMANOVA analysis revealed that polymer type explained 11.9 %-15.8 % of species composition variation. Transparent and black plastics hosted the most species, while multicolor plastics had the fewest. This study highlights that diverse microbial communities, particularly diatoms, colonize plastics in the Black Sea. Plastics can transport harmful species, posing ecological risks by disrupting benthic ecosystems, nutrient cycles, and ecosystem services like carbon storage and sediment stabilization. Our findings contribute understanding of the ecological and economic impacts of plastic debris at the seafloor.

The role of habitat preference and feeding strategy on exposure to microplastic pollution in freshwater fish species

Microplastic (MP) pollution has been observed in a variety of ecosystems, but there is a limited number of studies on reservoir ecosystems. The aim of this study was to determine the levels of MP contamination in sediment, water and commercially important fish species (Cyprinus carpio, Perca fluviatilis, Atherina boyeri and Sander lucioperca) collected from the Yamula Reservoir in Türkiye. Water samples were collectes at five stations. Four sediment samples were collected from the lake. As sediments from the lake represent a vital element of the lake ecosystem, they function as a historical archive that reflects alterations in land use and the characteristics of the lake over time. The average amounts of MPs observed in sediment and water samples were 0.12 MP/g and 0.58 MP/m3 respectively. The digestive systems of 30 individuals of each fish species were examined. The highest amount of MP was observed for C. carpio (6 ± 5.9 MP/individual), while the lowest amount of MP was observed for A. boyeri (1.8 ± 1.7 MP/individual). MP abundance in S. lucioperca and P. fluviatilis was 2 ± 2.8 and 4.6 ± 6.3 MP per individual. The most commonly observed polymer types were polypropylene (67%), polyvinyl alcohol (13%), polyethylene resin (13%) and high-density polyethylene (7%). The pollution load indexes determined for each fish species from the highest to the lowest were as follows: 1.83 (C. carpio) 1.6 (S. lucioperca) 1.05 (P. fluviatilis) and, 1 (A. boyeri). The findings of the study indicate that all sampling stations, including both sediment and water, are contaminated with MPs. Furthermore, the results demonstrate that all examined fish species ingest MPs. Additionally, the results indicate that fish inhabiting a wide range of habitats and consuming diverse diets are more susceptible to MP contamination.

Abundance and ecological risk of microplastics in commercial fish species from northeastern Mediterranean Sea

Microplastic pollution in marine environment has attracted the attention of scientists and policy makers. A substantial number of studies have examined the microplastic content in the gastrointestinal tract (GIT) of fish to monitor microplastic (MP) pollution levels in the ambient environment. The aim of the study was to access the microplastic abundance in the commonly consumed fish species and associated ecological risk assessment for consumers. To that end, microplastic presence in the gills and GIT of Boops boops, Mullus barbatus Mullus surmuletus, Saurida undosquamis, Sardina pilchardus, Trachurus mediterraneus, Pagellus erythrinus, Oblada melanurus, Diplous annularis was investigated. The polymer analysis of extracted MPs were done using Fourier transform infrared (FTIR) spectroscopy. Including all examined specimens, mean MP abundance in the GIT and gills were found as 0.8 ± 1.2 MPs/ind and 0.3 ± 0,7 MPs/ind, respectively. Consistent with the global picture, mainly detected MPs were fiber in shape (79%), black (39%) and blue (37%) in color, and less than 500 μm in size (63%). Polyethylene (21%), polyethylene derivatives (33%) and polypropylene (26%) were the most frequently detected polymers. Ecological risk assessment was calculated by employing polymer risk index, and varied between 4,6 and 27 indicating low to medium hazard risk for examined species. Hazard risk score showed that demersal and bentopelagic fish species were more prone to MP toxicity depending on the toxicity levels of identified polymers. Results indicated that polymer distribution in the marine environment is as significant as the habitat preferences of fish in determining the ecological risk posed by microplastic toxicity.

Microplastic contamination in the aquaculture icon Oreochromis mossambicus: Prevalence, characteristics, and comprehensive overview

The global production of plastics has surged to 368 million tonnes annually, leading to significant plastic waste accumulation, projected to reach 12,000 Mt by 2050, impacting aquatic ecosystems. Fish, crucial for their protein and nutrients, are particularly vulnerable to microplastic (MP) ingestion. As a major aquaculture producer and fish consumer, India faces rising plastic pollution in freshwater, which disrupts fish health and growth, posing a significant threat to the sustainability and productivity of aquaculture systems and potential health risks. This study focuses on Mozambique tilapia (Oreochromis mossambicus), valued for its widespread aquaculture use, rapid growth, and nutritional benefits. Our research reveals significant MP contamination (69.23 %) in Mozambique tilapia, with over 80 % from the Ulhas River and 60 % from the Bhima River contaminated and females showing higher susceptibility. These findings emphasise the need for further research on MP impacts on human health and the development of mitigation strategies.

Microplastic pollution levels in the surface water and sediment of Orontes basin: Urgent risk for endangered species

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.

The presence of microplastics in Baran's newt (Neurergus barani Öz, 1994) and the spotted newt (Neurergus strauchii Steindachner, 1887)

Microplastics (MPs), tiny plastic particles less than 5 mm in size, have emerged as a common and worrying pollutant in marine, freshwater, and terrestrial environments worldwide. In this study, we revealed the microplastic exposure of two endemic newt species for Türkiye. We found that polyethylene terephthalate (PET) was the predominant microplastic polymer type in both species, with the blue fiber shape in particular. We also found that there was a negative correlation between microplastic size and gastrointestinal tract (GIT) weight, but there was no significant difference between body length and GIT weight of both species. Our findings might be surprising as the studied species live in natural spring waters in remote, high-altitude areas. However, the detection of water bottles in their habitats appears to be the reason for their exposure to microplastic pollution. Therefore, reducing the use of single-use plastics is predicted to contribute to the conservation of these endemic newts.

Effect of parasitic infection on microplastic ingestion in a native leuciscid hybrid species (Alburnus derjugini x Squalius orientalis) from Kürtün Dam Lake, Türkiye

Microplastic (MP) pollution is currently one of the most serious environmental issues. MPs were investigated in the Kürtün Dam Lake in healthy individuals of the native leuciscid hybrid (Alburnus derjugini x Squalius orientalis) species and individuals infected with the Ligula intestinalis parasite. Although MP abundance appeared to be higher in non-infected fish (NIF) than in L. intestinalis (L) and infected fish (IF), the MP abundance in IF was higher, because the parasite theoretically belongs to IF. In addition to the observation of MPs in the gastrointestinal tract (GIT) of fish, the diffusion of MPs by parasites settled in the body cavity indicates that MPs are not only present in the GIT. Therefore, predation on existing fish by birds causes MP dispersion. In the present study, the most common MP shape was fiber (100% for NIF and IF, 85.7% for L), the MP color was black (57.1% for IF and L) and orange (50% for NIF), and the polymer type was polyamide (57.1% for IF, 50% for NIF) and polyethylene terephthalate (28.5% for L). These MP compositions led us to believe that textile effluents and aquaculture operations in dam lakes could be sources of pollution. Therefore, this study provides insights for future research to elucidate the connection between MP consumption and parasite infection.

Nanoplastic Exposure Mediates Neurodevelopmental Toxicity by Activating the Oxidative Stress Response in Zebrafish (Danio rerio)

The global accumulation and adverse effects of nanoplastics (NPs) are a growing concern for the environment and human health. In recent years, more and more studies have begun to focus on the toxicity of plastic particles for early animal development. Different particle sizes of plastic particles have different toxicities to biological development. Nevertheless, the potential toxicological effects of 20 nm NPs, especially on neurodevelopment, have not been well investigated. In this paper, we used fluorescence microscopy to determine neurotoxicity in zebrafish at different concentrations of NPs. Moreover, the behavioral analysis demonstrated that NPs induced abnormal behavior of zebrafish. The results revealed developmental defects in zebrafish embryos after exposure to different concentrations (0, 0.3, 3, and 9 mg/L) of NPs. The morphological deformities, including abnormal body length and the rates of heart, survival, and hatching, were induced after NP exposure in zebrafish embryos. In addition, the development of primary motor neurons was observed the inhibitory effects of NPs on the length, occurrence, and development of primary motor neurons in Tg(hb9:GFP). Quantitative polymerase chain reaction analysis suggested that exposure to NPs significantly affects the expression of the genes involved in the occurrence and differentiation of primary motor neurons in zebrafish. Furthermore, the indicators associated with oxidative stress and apoptosis were found to be modified in zebrafish embryos at 24 and 48 h following exposure to NPs. Our findings demonstrated that NPs could cause toxicity in primary motor neurons by activating the oxidative stress response and inducing apoptosis, consequently impairing motor performance.

Assessment of microplastic contamination in commercially available fishes

Plastics have widespread applications for human use, but their disposal poses a significant threat to living organisms and these plastics end up in the marine environment. They will be fragmented into small pieces as a result of ultraviolet exposure, climatic changes, and temperature changes; Microplastics (MPs) are plastics that are less than 5 mm in size. The level of MP (Microplastic) pollution in commercially harvested fish from different habitant in Vellore, India is currently unknown. Therefore, this study aimed to determine the presence and characteristics of ingested or inhaled MPs in marine and freshwater fishes highly consumed by the local population. Fish gills and gastrointestinal tracts were aseptically dissected and digested (30% hydrogen peroxide), then filtered and examined under a microscope for the presence of MPs. Further analysis was performed on the samples using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDAX). Of the samples analysed, a total of 875 MPs were recovered from 32 fishes, with 478 from marine fishes and 397 from freshwater fishes. The most common colours of the MPs were blue and black, while stereo microscopy analysis revealed that the majority of MPs were fibers (91%), followed by fragments (8%) and a small number of films. The ATR-FTIR analysis identified polyvinyl alcohol (39.76%), polyethylene (16.51%), methylcellulose (12.84%) and styrene (9.07%), as the predominant types of MPs in the fish samples. This study highlights the significant impact of MP pollution on marine ecosystems. The research provides insight into the nature and extent of MPs in fish from both marine and freshwater habitats, with an aim for policies and interventions aimed to reduce plastic pollution in the locality.

Potential synergy of microplastics and nitrogen enrichment on plant holobionts in wetland ecosystems

Wetland ecosystems are global hotspots for environmental contaminants, including microplastics (MPs) and nutrients such as nitrogen (N) and phosphorus (P). While MP and nutrient effects on host plants and their associated microbial communities at the individual level have been studied, their synergistic effects on a plant holobiont (i.e., a plant host plus its microbiota, such as bacteria and fungi) in wetland ecosystems are nearly unknown. As an ecological entity, plant holobionts play pivotal roles in biological nitrogen fixation, promote plant resilience and defense chemistry against pathogens, and enhance biogeochemical processes. We summarize evidence based on recent literature to elaborate on the potential synergy of MPs and nutrient enrichment on plant holobionts in wetland ecosystems. We provide a conceptual framework to explain the interplay of MPs, nutrients, and plant holobionts and discuss major pathways of MPs and nutrients into the wetland milieu. Moreover, we highlight the ecological consequences of loss of plant holobionts in wetland ecosystems and conclude with recommendations for pending questions that warrant urgent research. We found that nutrient enrichment promotes the recruitment of MPs-degraded microorganisms and accelerates microbially mediated degradation of MPs, modifying their distribution and toxicity impacts on plant holobionts in wetland ecosystems. Moreover, a loss of wetland plant holobionts via long-term MP-nutrient interactions may likely exacerbate the disruption of wetland ecosystems' capacity to offer nature-based solutions for climate change mitigation through soil organic C sequestration. In conclusion, MP and nutrient enrichment interactions represent a severe ecological risk that can disorganize plant holobionts and their taxonomic roles, leading to dysbiosis (i.e., the disintegration of a stable plant microbiome) and diminishing wetland ecosystems' integrity and multifunctionality.

Long-term investigation of microplastic abundance in Squalius species in Turkish inland waters

Examining the enduring alterations in microplastic (MP) concentrations within fish in inland waters is of utmost importance in understanding the historical trajectory of plastic waste and formulating consequential predictions regarding upcoming pollution levels. This study includes the collection of fish samples from 22 different river basins in Türkiye and all Squalius species distributed in Türkiye, covering the years 2004-2018, and examined the presence of MP in museum specimens' gastrointestinal tracts (GITs). 331 specimens were examined, and microplastic was observed in 20.8% (69). A mean value of 0.27 ± 0.19 MP per individual was observed, resulting in a cumulative score of 91 MP. Most observed MPs were composed of fiber, representing 79.1% of the total. The polymer types identified were mostly polyethylene (PE) at 38.5% and polyethylene terephthalate (PET) at 29.7%. The black color was prominent among MPs, and MP length ranged between 101 and 4963 μm. The analysis revealed no statistically significant difference in the mean MP values across different years and basins. There is no substantial correlation between the abundance of MP and the sizes of fish, population density, or quantities of plastic production. The data indicate that MP has persistently acted as a contaminant in freshwater ecosystems over an extended period. It is projected that the laundering of synthetic textiles serves as the primary contributor to MP contamination in freshwater bodies. Our results offer significant baseline data on the pervasive issue of MP pollution in the freshwater environment. These findings enable us to gain profound insights into the current state of MP contamination in fish residing in lotic systems while empowering us to make accurate predictions about its future trajectory.

Microplastic in fishes: the first report from a Himalayan River - Alaknanda

The present study aimed to understand microplastic (MP) ingestion by five fish species with different feeding habits namely, Schizothorax richardsonii and Crossocheilus latius (herbivore),Cyprinus carpio (omnivore), Tor chelenoid (herbi-omnivore), and Botia horii (carnivore). The fishes were sampled from River Alaknanda (one of the headwaters of River Ganga) patch at Srinagar, Garhwal, Uttarakhand. The fish gut samples were digested with 30% hydrogen peroxide and vacuum filtered through glass microfiber filter. Each filter paper was observed microscopically to count MPs, and then, selected MPs were chemically characterized using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The results revealed that all the species were contaminated with MPs and the rate of MP ingestion varied with feeding habits. The herbi-omnivore fish, Tor chelenoid, was observed to have the highest MP ingestion. Among the analyzed particles, fibers (66%) were the dominant type of MPs. The MPs were chemically characterized as High-Density Polyethylene (HDPE), Polypropylene (PP), and Polyester. This study contributes as a reference for the forthcoming researches, as it is the pioneer work on the ingestion of MP by fishes of a Himalayan River.

Microplastics Contamination in the Edible Fish Mozambique Tilapia (Oreochromis mossambicus) from the Selvampathy Wetland of Coimbatore, Tamil Nadu, India

The present study investigated the microplastics (MPs) contamination in the gastrointestinal (GI) tract, gills and muscle of the Mozambique tilapia, Oreochromis mossambicus sampled from the Selvampathy Lake of Coimbatore, Tamil Nadu. MPs abundance was found in 10 to 28, 8 to 27, and 4 to 12 particles and their size ranged between 4.4 and 210, 4.6 to 180, and 4.5 to 194 μm in the GI tract, gills and muscle, respectively. MPs were dominantly shaped as fibres (95%) and fragments (5%) with the following colour pattern of blue > black > pink > transparent > and others. Extracted MPs polymer nature were polyethylene (54%), polyamide (38%) and polypropylene (8%). The present study reveals that the edible fish O. mossambicus had MPs that can be transferred to consumers. Moreover, urban discharges, including domestic wastes, agricultural and rainwater runoff, might be possible MPs sources to the studied wetland.

Recent advances in inspection technologies of food safety health hazards for fish and fish products

The development of reliable and sensitive detection methods is essential for addressing the escalating concerns surrounding fish and fish products, driven by increasing market demands. This comprehensive review presents recent advances in detection approaches, specifically focusing on microplastic, biological, and chemical hazards associated with these products. The overview encompasses 21 distinct detection methods, categorized based on the type of hazard they target. For microplastic hazards, six methods are visual, spectroscopic, and thermal analyses. Biological hazard identification relies on six approaches employing nucleic-acid sequence, immunological, and biosensor technologies. The investigation of chemical hazards encompasses ten methods, including chromatography, spectroscopy, mass spectrometry, immunological, biosensor, and electrochemical techniques. The review provides in-depth insights into the basic principles, general characteristics, and the recognized advantages and disadvantages of each method. Moreover, it elaborates on recent advancements within these methodologies. The concluding section of the review discusses current challenges and outlines future perspectives for these detection methods. Overall, this comprehensive summary not only serves as a guide for researchers involved in fish safety and quality control but also emphasizes the significance of staying abreast of evolving detection technologies to ensure the continued safety of fish and fish products in response to emerging food safety hazards.

Plastics in an endemic fish species (Alburnus sellal) and its parasite (Ligula intestinalis) in the Upper Tigris River, Türkiye

Occurrence of micro-, meso- and macroplastics in Alburnus sellal and its parasite Ligula intestinalis is reported for the first time in the Tigris River, one of the two large rivers that defines Mesopotamia. Plastic occurrence was assessed from museum fish materials collected in the upper Tigris River between 2007 and 2021. Plastics were found in 57 % of A. sellal specimens (536 individuals) and in 74 % of L. intestinalis specimens (57 individuals). Mean plastic ingestion was 1.27 ± 1.30 items. fish-1 and 1.77 ± 1.79 items. parasite-1 considering all the fish and parasites analysed. Fibres were the most common types of plastics, comprising 96.2 % and 81 % of plastics in A. sellal and L. intestinalis, respectively. Black was the most common colour of plastics found in both fish (37 %) and parasite specimens (58 %). Microplastics comprised 95.5 % and 100 % of plastics found in A. sellal and L. intestinalis, respectively. In both specimens acrylic (PAN) was the most common polymer as confirmed by FTIR spectroscopy. Differences in plastic ingestion were not significantly over time and among regions. No significant correlation was found between plastics ingestion by fish and by parasites. The present assessment shows that native fish species of the Tigris River have been contaminated by plastics by more than a decade. Our results contribute to a better understanding of the status of plastic pollution in fish and parasites, provide plastic pollution baseline data for the Tigris River and highlight the urgent need to elucidate on the distribution and fate of plastics in freshwater environments and their effects on the ecosystem and humans.

Seasonal monitoring of microplastic pollution in the Southeast Black Sea: An example of red mullet (Mullus barbatus) gastrointestinal tracts

This study investigated seasonal presence of microplastic (MP) in gastrointestinal tracts of red mullet (Mullus barbatus) sampled from the Southeast Black Sea Region. A total of 335 MPs were detected in 120 individuals. While the most MP was observed in the winter and autumn seasons, quite few MPs were found in the summer and spring seasons. MP size did not show significant difference among seasons. While all of the MPs in the autumn and spring and most of the MPs in the winter were fiber-shaped, most of the MPs in the summer were fragments. The most observed MP color for all seasons was white. While polymer structures did not show much variation in spring and summer, six different polymers were determined for both autumn and winter. In general, less MPs were detected during fishing ban period (summer) and the characteristic properties of the detected MPs suggest a MP pollution in the region due to intense fishing activities.

Neurotoxicity of polystyrene nanoplastics with different particle sizes at environment-related concentrations on early zebrafish embryos

Nanoplastics (NPs) have received global attention due to their wide application and detection in various environmental or biological media. NPs can penetrate physical barriers and accumulate in organisms after being ingested, producing a variety of toxic effects and possessing particle size-dependent effects, distinguishing them from traditional contaminants. This paper explored the neurotoxicity of polystyrene (PS)-NPs of different particle sizes on zebrafish (Danio rerio) embryos at environmental concentrations at the tissue and molecular levels using visualized transgenic zebrafish. Results showed that all particle sizes of PS-NPs produced developmental toxicity in zebrafish embryos and induced neuronal loss, axonal deletion/shortening/hybridization, and developmental and apoptotic-related genetic alterations, ultimately leading to behavioral abnormalities. PS-NPs with smaller sizes may have more severe neurotoxicity due to their entry into the embryo and brain through the chorionic pore before hatching. In addition, PS-NPs at 100 nm and 1000 nm can specifically interfere with GABAergic, cholinergic or serotonergic system and affect neuronal signaling. Our results reveal the neurotoxic risk of NPs, and smaller particle-size NPs may have a greater ecological risk. We anticipate that our study can provide a basis for exploring the toxicity mechanisms of NPs and the environmental risk assessment of NPs.

Exploring microplastic pollution in a Mediterranean river: The role of introduced species as bioindicators

Studies of plastic contamination in freshwater ecosystems and their biota remain scarce, despite the fact that the vast majority of plastic waste initially passes through lotic ecosystems. Biomonitoring provides valuable information regarding plastic pollution and microplastic threats to biota and human health. The aim of this study was to explore the potential use of a non-indigenous fish species as a bioindicator of microplastic pollution in an Eastern Mediterranean River. Our study area is located in a heavily modified and vastly impacted urban river which flows through the largest part of the Metropolitan area of Athens, Greece. We used an introduced chub species (Squalius vardarensis) to assess microplastic ingestion in the river. The results indicated moderate occurrence and abundance of microplastics in the fish gastrointestinal tracts; one-third of specimens (35%) contained microplastics, although the average number of microplastics per specimen was relatively low (1.7 ± 0.2). Overall, the abundance of microplastics in the water confirmed the moderate level of microplastics contamination in our study area. The major polymer types of microplastics identified by FT-IR analysis were: polyethylene (PE), polyvinyl alcohol (PVA) and polypropylene (PP); reflecting the fragmentation of larger litter from industrial packaging and/or household goods. Surface runoff of the urban environment, via motorways and major road networks, could be the contributing factor to the reported microplastics. Our results suggest that generalist's non-indigenous species such as chubs could be used as bioindicators of microplastics in inland waters. Introduced fishes can be a feasible, nondestructive, and cost-effective option for the assessment of microplastics in freshwater ecosystems, while freshwater chubs' high abundance and omnipresence in European rivers further serve this scope. However, it is worth noting that the suitability of any particular species as a bioindicator of microplastics may depend on a variety of factors, including their feeding behavior, habitat, and exposure to microplastics in their environment.

Microplastics abundance in abiotic and biotic components along aquatic food chain in two freshwater ecosystems of Pakistan

Contaminants of global concern, microplastics (MPs) have been lately reported to be found almost everywhere. Yet there is limited evidence to suggest if these tiny particles can bioaccumulate and biomagnify along the food chain. The current study was conducted to quantify MPs load in two fresh water bodies i.e. River Ravi (Pakistan) and a fish rearing pond fed with ground water to trace MPs along the food chain including biotic and abiotic components. Samples were taken from air, water, sediments, planktons, fish and avian specimen from both water bodies. Higher MPs were found in all samples taken from river Ravi ranging from 3.0 ± 1.58 MPs items in water to 15.20 ± 3.35 MP items in air as compared to 2.8 ± 1.79 MPs in water to 11.20 ± 1.89 air-borne MP items in fish rearing ponds respectively. The mean value of MP items in the GIT of all species was higher (5.05 ± 2.25) as compared to the respiratory tract (1.57 ± 1.3) suggesting ingestion as main mode of exposure. However, this mode of exposure needs to be further investigated along with other exposure routes. Presence of MPs at all trophic levels under investigation indicates some degree of bioaccumulation of these pollutants in the ecosystems.

Decade of microplastic alteration in the southeastern black sea: An example of seahorse gastrointestinal tracts

Unconscious and excessive use of plastic supports the diversity and abundance of microplastics (MPs) in marine environments. As a result of MP exposure, organisms in the marine environment are faced with adverse scenarios up to death. In this study, ten-year MP composition was investigated in gastrointestinal tracts (GITs) of low-mobility seahorses (90 individuals per period) from the Southeastern Black Sea. Seahorse GITs sampled during both 2012 and 2022 contain 102 and 135 MP items, respectively. The number of MPs per unit individual seahorse and unit seahorse weight was higher in the 2022 period. On the other hands, no significant differences were observed between the MP lengths of both periods. The majority of MPs in both sample periods were materials shorter than 1000 μm. Of the eight found synthetic polymers, five belonged to the 2012 period, while seven were observed during the 2022 period. Additionally, the most abundant synthetic polymer for both periods is polyvinyl stearate (PVS). As a result, 43% of the total plastic material belonged to the 2012 period, while 57% was observed in the 2022 period. Considering both the diversity of polymers and the abundance of plastics, the region was adversely affected by plastic materials in the 2022 period.

Microplastics in Commercial Fishes and By-Catch from Selected FAO Major Fishing Areas of the Southern Baltic Sea

According to recent world wide studies, microplastics (MPs) have been found in many fish species; however, the majority of research has focused only on the gastrointestinal tract, neglecting edible organs. This study aimed to assess the presence of microplastics in the non-edible (gills, digestive tract) and edible organs (liver) of three commercial fish species and twoby-catch species from the southern Baltic Sea. Fish (Clupea harengus, Gadus morhua, Platichthy sflesus, Taurulus baublis, Cyclopterus lumpus) were caught in 108 and 103 FAO Fishing Zones belonging to the Polish fishing zone. The abundanceof MPs ranged from 1 to 12 items per fish, with an average of 4.09 items. MPs were observed in different organs, such as the liver, gills, and digestive tract of all five tested species. MPs recognized as fibers were the most abundant. Other shapes of polymers found in fish organs were pellets and particles of larger plastic pieces. The dominant color of the MPs was blue, but there were also red, black, transparent, yellow, green, and white items found. According to dimensions, dominant MPs were between 0.1 and 0.5 mm in size. The chemical characterization of polymers accomplished by the use of Fourier Transform Infrared (FT-IR) Spectroscopy demonstrated the abundance of cellophane, polyamide, polyethylene, polypropylene, polyethylene terephthalate, polyvinyl propionate, polyacrylonitrile, and polyester.

Factors influencing the variation of microplastic uptake in demersal fishes from the upper Thames River Ontario

Microplastics (plastic particles <5 mm) are abundant in aquatic environments, particularly near urban areas. Little is known, however, about how variations in microplastic abundances within watersheds affect fishes. Microplastics were examined in demersal fishes-white sucker (Catostomus commersonii) and common carp (Cyprinus carpio)-across 11 sites in the Thames River, Ontario, Canada. Microplastics were found in 44% of white sucker, ranging from 0 to 14 particles per fish, and 31% of common carp, ranging from 0 to 128 particles per fish. Across both species, the number of microplastics was higher in urban sites than rural sites, and there was a positive relationship between the number of microplastics in the fish and the abundance of microplastics in the sediment. Body mass was also positively related to number of microplastics in fish. Together these results provide insight into environmental and biological factors that may be influencing microplastic ingestion in demersal fishes.

Microplastic ingestion evidence by economically important farmed fish species from Turkey

Microplastic pollution and its potential impacts on humans become a global concern. This study is the first study examining the microplastic ingestion in the commercially important species Oncorhynchus mykiss Rainbow trout (Walbaum, 1792), Sparus aurata Gilthead seabream Linnaeus, 1758, and Dicentrarchus labrax European seabass (Linnaeus, 1758) from Turkey. The occurrence frequency of microplastic (MP)in the gastrointestinal tract (GIT) was varied between 50 and 63 %. The highest MP abundance in the GIT was estimated in Rainbow trout (1.2 MPs individual^-1) followed by European seabass (0.95 MPs individual^-1) and Gilthead seabream (0.8 MPs individual^-1). Most of the extracted microplastic particles were black (61 %) and blue (27 %) in color and fiber (80 %) in shape. Major identified polymers were polyethylene (25 %), polyester (20 %), polyamide (10 %). Since fish consumption is an important route for MPs, results light up the danger potential for humans. This study will fill the information gap in Turkey and show the necessity of protection measures in aquaculture industry.

First record of microplastic occurence at the commercial fish from Orontes River

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 μm 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 bioaccumulation in estuary-caught fishery resource

The environmental behavior of microplastics (MPs) in estuaries with saline and freshwater intersections is extremely complex. This increases the chance of MP ingestion by fishery resources, posing potentially tremendous health risks for humans. Herein, a total of 105 fishes from 14 different species, and 86 crustaceans (including shrimps and crabs) from five different species were sampled in the Yangtze River estuary and offshore, and MP bioaccumulation, accumulative organ, and the influencing factors were comprehensively studied. The results elucidated that MP accumulation in benthos was significantly higher than that in pelagic animals due to the lower acceptance threshold, assimilation efficiency and egestion rate for benthos. The MP content in crustaceans with the burrowing favoring the MP retention was significantly higher than that in fishes. MPs ingested by fish can accumulate in skin, gills and viscera rather than muscles. Most MPs accumulated in fishery resources were cellulose and polyethylene terephthalate characterized by black and gray fibrous and lengths ranging from 0.1 mm to 1 mm. The gill retention capacity of pelagic fish to smaller-size (<0.1 mm) MPs was pronouncedly stronger than that of benthic fish. It was more accurate to assess the ecological risk of MPs in terms of the maximum size of MPs accumulated in organisms. Compared with the offshore area, the incidence of MP uptake was higher in the estuary owing to anthropogenic impacts. This study helps understand the transfer of MPs in aquatic food webs and offers a foundation for assessing the risk of human exposure to MPs.

Microplastic contamination in seafood from Dongshan Bay in southeastern China and its health risk implication for human consumption

Microplastic (MP) pollution has been a considerable concern due to its ubiquity in the environment and its potential to harm human health. Unfortunately, the exact levels of MP in various species of seafood species have not been established. It is also unclear whether or not consuming seafood contaminated with MPs directly jeopardizes human health. Here, eight popular species of seafood in Dongshan Bay, China were investigated to determine the presence of MP pollution and its implications on human health. The abundance, color, size, shape, type, surface morphology, danger of the MPs extracted from the seafood were analyzed. Results showed that the average MP abundance in the shellfish and fish was 1.88 ± 1.44 and 1.98 ± 1.98 items individual^-1, respectively. The heavy presence of fibers may be attributed to the shellfish and fish's feeding behaviors as well as their habitat and environment. The sizes of MPs found were below 1.0 mm. The main types of MP found in the shellfish were PES and PET, whereas the main types found in the fish were PS and PES. Risk assessment suggested that MPs in the shellfish (risk Level V) posed a greater and more direct threat to human health if the shellfish is eaten whole. The MPs in the gastrointestinal tracts (GITs) of fish (risk Level IV) have a relatively limited effect on human health since GITs are seldom consumed by humans unless the fish is heavily processed (canned or dried). MPs-induced health risk is predicted using a technique called molecular docking. The results of this study not only establish levels of MP pollution in popular seafood species but also help understand the implications of consuming MP-contaminated seafood on human health.

A Meta-Analysis of the Characterisations of Plastic Ingested by Fish Globally

Plastic contamination in the environment is common but the characterisation of plastic ingested by fish in different environments is lacking. Hence, a meta-analysis was conducted to identify the prevalence of plastic ingested by fish globally. Based on a qualitative analysis of plastic size, it was determined that small microplastics (<1 mm) are predominantly ingested by fish globally. Furthermore, our meta-analysis revealed that plastic fibres (70.6%) and fragments (19.3%) were the most prevalent plastic components ingested by fish, while blue (24.2%) and black (18.0%) coloured plastic were the most abundant. Polyethylene (15.7%) and polyester (11.6%) were the most abundant polymers. Mixed-effect models were employed to identify the effects of the moderators (sampling environment, plastic size, digestive organs examined, and sampling continents) on the prevalence of plastic shape, colour, and polymer type. Among the moderators, only the sampling environment and continent contributed to a significant difference between subgroups in plastic shape and polymer type.

A review of plastic pollution in aquatic ecosystems of Turkey

Turkey is one of the major plastic pollution sources in the Mediterranean and the Black Sea. This review summarizes present information, data, and legislation on plastic pollution in Turkish aquatic ecosystems. According to results derived from reviewed studies, both macro- and microplastic pollutions were documented in Turkish aquatic ecosystems. Most of the studies on plastic pollution in Turkish waters were performed in the marine environment while only four were conducted in freshwater environments. Spatially, the majority of these studies, which were on levels in the marine environment, were conducted on the northeastern Mediterranean coasts of Turkey, especially Iskenderun and Mersin Bays. Additional studies were carried out on either the ingestion/presence/impact of microplastics by/to aquatic organisms or the entanglement of marine organisms in plastics. There were also studies assessing the microplastic content of commercial salt, and another has reported microplastic presence in traditional stuffed mussels sold in Turkish streets. Some studies were conducted on microplastic presence and/or their removal in wastewater treatment plants in Mersin, Adana, Mugla, and Istanbul cities. Macro- and microliter loading from a few Turkish rivers to the sea was also estimated. All these investigations indicate that Turkish aquatic environments have significant plastic pollution problems, which were also underlined by the legislative studies. The need for further studies in this field still exists, especially in freshwater environments.