Contaminants In Fish Research Articles

Levels and Classification of Microplastics and Their Impact on the Wellbeing of Selected Commercially Important Fish Species in Kisumu Bay, Lake Victoria.

Microplastics (MPs) are emerging pollutants of concern in aquatic ecosystems. Fish ingest MPs accidentally during normal feeding because they resemble prey or by ingesting prey that previously consumed them. Despite severe plastic pollution in Africa, some countries, including Kenya have implemented laws to curb this pollution menace. MPs have scantly been studied in African freshwaters. This study provides empirical data and describes the levels of MPs in four commercially important fish species in Lake Victoria. A total of 95 fish samples were collected from four sampling sites (inshore-offshore waters) between March and May 2022. Microscopy and Attenuated Total Reflectance Fourier Transformed Infrared (ATR-FTIR) spectroscopy methods were used to identify MPs. In this study, 62 out of 95 (65.26%) of the gastrointestinal tracts of the sampled fish contained MPs. The four species showed different proportions of detected MPs among the sampled individuals: 75.00% (Clarias gariepinus), 75.00% (Synodontis victoriae), 71.43% (Lates niloticus), and 59.26% (Oreochromis niloticus). Polystyrene (PS) and poly (perfluorobutadiene) were the main plastic polymers in the fish samples. The condition factors estimated for O. niloticus, S. victoriae, and L. niloticus were > 1 and < 1 for C. gariepinus, respectively. Positive correlations were observed between microplastic numbers and fish length and microplastic numbers and fish weight. However, the low R2 values obtained implied no strong relationship exists between these parameters. These findings provide evidence of microplastic contamination in fish in Kisumu Bay.

The persistent DDT footprint of ocean disposal, and ecological controls on bioaccumulation in fishes

Globally, ocean dumping of chemical waste is a common method of disposal and relies on the assumption that dilution, diffusion, and dispersion at ocean scales will mitigate human exposure and ecosystem impacts. In southern California, extensive dumping of agrochemical waste, particularly chlorinated hydrocarbon contaminants such as DDT, via sewage outfalls and permitted offshore barging occurred for most of the last century. This study compiled a database of existing sediment and fish DDT measurements to examine how this unique legacy of regional ocean disposal translates into the contemporary contamination of the coastal ocean. We used spatiotemporal modeling to derive continuous estimates of sediment DDT contamination and show that the spatial signature of disposal (i.e., high loadings near historic dumping sites) is highly conserved in sediments. Moreover, we demonstrate that the proximity of fish to areas of high sediment loadings explained over half of the variation in fish DDT concentrations. The relationship between sediment and fish contamination was mediated by ecological predictors (e.g., species, trophic ecology, habitat use), and the relative influence of each predictor was context-dependent, with habitat exhibiting greater importance in heavily contaminated areas. Thus, despite more than half a century since the cessation of industrial dumping in the region, local ecosystem contamination continues to mirror the spatial legacy of dumping, suggesting that sediment can serve as a robust predictor of fish contamination, and general ecological characteristics offer a predictive framework for unmeasured species or locations.

Examining Bald Eagle Contaminant Exposure and Reproductive Risk Above and Below Dams on Great Lakes Tributaries.

Removing lowermost dams can reestablish fish passage on Great Lakes tributaries. This can increase the transfer of contaminants from anadromous fish to piscivorous wildlife upstream; however, concentrations of bioaccumulative contaminants in Great Lakes fish have decreased over the last several decades. We analyzed concentrations of PCBs and the toxic equivalence (TEQs) calculated from PCBs, DDTs, other organochlorine pesticides, and PBDEs in the plasma of bald eagle nestlings above and below lowermost dams on five river systems in Michigan from 1999 to 2013. We examined relationships between contaminants and metrics of reproductive success from 1997 to 2018, including the effects of year and location relative to the lowermost dam. Σ20PCB and p,p'-DDE were important in characterizing differences in contaminant mixtures above and below dams. Concentrations of contaminants were generally greater below dams than above. There were generally greater nest success and more nestlings per nest below dams, but nest location explained little variability (R2 values = 0.03-0.15). Neither Σ20PCB nor p,p'-DDE was a significant predictor of 5-year productivity means by river reach despite concentrations exceeding previously established effects thresholds for healthy bald eagle populations in the Great Lakes (≥ 1 nestling/nest). Our study indicates that dams may continue to reduce the upstream movement of contaminants to bald eagles, but at the measured concentrations, contaminants did not impair productivity and reproductive success as indicated by nestlings per nest. Additional information about population dynamics could clarify population-level effects of contaminants on bald eagles and to what degree these populations are self-sustaining throughout the Great Lakes.

Microplastic and associated emerging contaminants in marine fish from the South China Sea: Exposure and human risks

Microplastics can act as vectors of chemical contaminants in aquatic environments, but the extent to which this phenomenon contributes to chemical exposure in marine organisms remains poorly understood. We investigated the occurrence of microplastics and emerging contaminants (ECs), including antibiotics and per- and polyfluoroalkyl substances (PFAS) in 14 marine fish species. Microplastics were detected in all marine fish species, mainly in the gastrointestinal tract. Fluoroquinolones and tetracyclines were the dominant antibiotics in fish muscles with maximum concentrations of 24.84 and 26.95 ng g−1 ww, while perfluorooctanesulfonic acid (PFOS, 0.039–0.95 ng g−1 ww) was the dominant component in the PFAS profile. Fish with more microplastics had significantly higher concentrations of fluoroquinolones and perfluoroalkyl acids than fish with less microplastics (p < 0.05), but the correlation was not observed in other chemicals. Structural equation modeling revealed the contribution of microplastics in fish on the level of ECs contamination. The health quotient value indicated the low health risk of single compounds via fish consumption to humans; however, the combined risk of microplastics and ECs still needs to be considered. This work highlights the link between microplastics with associated ECs ingested by aquatic organisms and the human health risk of consuming polluted seafood.

Pervasive Microplastic Ingestion by Commercial Fish Species from a Natural Lagoon Environment

Microplastics have emerged as a significant global environmental concern in the recent decade. The aim of this study was to elucidate microplastic contamination of commercial fish species in a natural lagoon environment. Microplastic contamination was examined in the gastrointestinal tracts and gills of 157 commercial fish from 18 species with varying feeding habits in a vital and sensitive lagoon ecosystem, which connects to the Indian ocean. Microplastics were extracted using digestion, followed by stereomicroscopic inspection using Nile Red stain, and identified via μ-FTIR analysis. Over half of studied fishes ingested microplastics (54.14%). Filaments (50%) and blue items (43%) were the most commonly ingested. Of all the fish species, Eubleekeria splendens had the highest average concentration of microplastics in GIT (1.41 ± 2.52 items/g w.w. tissues), although no statistically significant difference in amount of ingested microplastics (items/g w.w. tissues) was observed among species. The highest concentrations of inhaled microplastics were recorded in Sillago vincenti (1.38 ± 1.30 items/g w.w. tissues). The majority of the extracted microplastics (33%) belonged in the size class 500–1500 μm with rayon, polyethylene terephthalate, and polypropylene as the primary polymers. This study found no correlation between microplastic ingestion and fish species and feeding habits, but a positive correlation with fish size was observed. These findings reveal widespread microplastic contamination in edible fish, posing potential risks to commercially important species due to increasing pollution in lagoon ecosystems.

Bioaccumulation, contamination and health risks of trace elements in wild fish in Chongqing City, China: a consumer guidance regarding fish size.

Trace elements generally contaminate wild fish, particularly in megacities, necessitating guided consumption practices. This study investigated the bioaccumulation of trace elements in wild fish from Chongqing City in June 2021. We evaluated their contamination and associated health risks to establish consumption guidance based on fish size. Our results indicate that the concentrations of Zn, Pb, Cr, and As were relatively high, with some fish exceeding the maximum residue limits. Herbivorous and pelagic fish generally exhibited lower bioaccumulation of most trace elements, except for Cr and As, which were higher in pelagic species. The contamination indices (Pi) for Cr, Pb and As were consistently above 0.2, indicating widespread contamination. The most contaminated fish typically measured around 19cm in length and weighed approximately 90g. Only the maximum target hazard quotients (THQ) for As, Cr, and Hg exceeded 1, with a notably high ratio of THQ(As) > 1, highlighting concerns over arsenic contamination. The THQ(As) remained below 1 for adults across all fish species, whereas for children, species such as Onychostoma sima, Pseudohemiculter dispar, and Parabramis pekinensis exceeded this threshold. Fish safe for adult consumption generally measured 13cm in length and weighed 20g, and for children, 16cm and 25g. Consequently, selecting larger fish is likely to reduce the consumption of contaminated fish, thereby decreasing health risks to the public. The centralization of contaminated fish with high risk in specific size range confirmed fish size could be used to gauge the contamination and health risk of fish.

Seasonal variability of microplastic contamination in marine fishes of the state of Gujarat, India.

Seasonal variation in microplastics abundance, occurrence, and distribution in pelagic and demersal fishes was observed in this study during December 2021 to November 2022. One hundred percent presence of microplastic in inedible (gut and gills) tissue, while 82% and 54% in edible tissue (muscle) of pelagic and demersal fishes respectively were seen. Post-monsoon period showed high prevalence of microplastics followed by monsoon and the least during pre-monsoon in both pelagic and demersal fishes. In pelagic fishes, the edible tissue had microplastics abundance of 1.56 to 13.34 numbers per 10g of tissue whereas inedible tissue had 3.36 to 16.67 numbers per 10g of tissue. In demersal fishes, the edible tissue had microplastics abundance of 1.04 to 5.26 numbers per 10g of tissue while it was 2.67 to 8.34 numbers per 10g of inedible tissue. There was significant variation in abundance of microplastic in edible and inedible tissue of all the fishes (Mann-Whitney test, p < 0.05). The most dominant microplastics size was 0.005-0.05mm followed by 0.05-0.5mm and the least of greater than 0.5mm in pelagic and demersal fishes respectively. Taking microplastic shape into consideration, the most dominant was fiber followed by fragment and the film in inedible tissue of all the fishes. The edible tissue of all the fishes had only fiber in them (100% occurrence). The dominance of blue color microplastics was observed followed by red, green, yellow, and orange at least in edible as well as inedible tissues of the fishes. More than 99% microplastics polymer observed in this study include polyethylene (PE), polypropylene (PP), and polystyrene (PS); only less than 1% was unidentified. This is the first study done on seasonal variation of microplastic in the marine fish population of Gujarat waters, Northeast Arabian Sea. The study highlights the nature of micro-pollutant in marine environments, emphasizing the need for comprehensive monitoring and management strategies.

Investigation of Microplastic Contamination in the Gastrointestinal Tract of Fish: A Comparative Study of Various Freshwater Species

The aqueous environment has been reported to be seriously threatened by the pollution of microplastics (MPs), which has been confirmed in numerous studies affecting various aquatic habitats. Despite this, few investigations exist on MP contamination in fish of specific regions. Thus, the current study aims to determine MP concentrations in the fish species of the Chhota Nagpur zone of eastern India. From August to September 2023, fish samples were collected from 10 km distance between two locations of Subarnarekha and Kharkai river banks through fishermen. Microplastics were found in the gastrointestinal tract of 45 fish of 8 species out of 48 samples. Of these species, six species were secondary consumers, while the remaining two were primary consumers. The average amount of microplastics consumed by each fish (n = 48) was 3.0 ± 1.8. A total of 144 microplastics were found in collected samples of fish species. Among the analyzed sample of MPs, 69.4% were fibers, films were (22.3%), and (8.3%) were fragments. The least contaminated species was T. ilisha (0.8 ± 0.7 particles/ind.), while L. rohita had the highest microplastic contamination (4.5 ± 1.7 particles/ind.). The present study found a negative correlation of - 0.83 between MP consumption and the mean body weight of fish. Similarly, a negative correlation of - 0.5 was found between the length of fish and MP intake. Polyamide (nylon), polypropylene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, and polyethylene polymers were found. The size of MPs ranged from 45-355 μm and mainly were fibers. They were also predominantly blue and black. Polyamide and polyvinyl chloride were the common MP types in every specimen. The possible sources of MPs were fishing nets, ropes, and packaging material. This investigation points to MP contamination in aquatic ecosystems and particular species. It provides advanced knowledge of MP pollution, sources, and effects on regional ecosystems and public health.

Method validation for the detection of formaldehydein fish using ultra performance liquid chromatography

Formaldehyde, the simplest aldehyde, tops the list of illegal and harmful food contaminants. Recently, formaldehyde has been used indiscriminately to preserve the freshness and quality of fish. Numerous incidents of formalin (a solution of formaldehyde) misuse during the storage and transportation of fish have been reported in several parts of India. In this context, it is pertinent to study formalin contamination in fish and shellfish. Protocol for detection of free and bound formaldehyde by ultra-performance liquid chromatography (UPLC) was attempted in the present study. Formaldehyde peak was observed in the expected retentiontime and standardisation of the protocol for formaldehyde determination was then carried out. UPLC method was developed and validated for specificity, repeatability, accuracy, and linearity. The average correlation coefficient (R2) was 0.99. The recovery rates of free and bound formaldehyde were 90.83 to 116.43% and 88.76 to 132.98%, respectively. The limit of detection (LOD) was found to be 0.5 ppm. The study investigated free and bound formaldehyde levels in commonly traded fish species across five major fish markets inTamil Nadu, India. Sphyraena barracuda had the highest recorded concentrations of free and bound formaldehyde at 9.8 and 6.45 mg kg-1, respectively, while Lethrinus lentjan exhibited the lowest concentrations at 0.8 mg kg-1 for free formaldehyde and 0.5 mg kg-1 for bound formaldehyde. Keywords: Formalin abuse, Limit of detection, Method validation, Retention time UPLC

Study of Fungal Organisms Associated with Smoked and Dried Fish Sold in Awka Markets, Anambra State

Fungal contamination of fish is considered as the major cause of spoilage and it constitutes a significant public health problem. This study was carried out to determine the fungal organisms associated with smoked and dried fish samples: Scomber scombrus (Mackerel), Sardinella longiceps (Sardine), Oreochromis niloticus (Tilapia), Clarias gariepinus (catfish), Gadus morhua (Stock fish), Ethmalosa fimbriata (Bonga fish), and Citharinus citharus (Mangala) sold in Awka markets, Anambra State, Nigeria. A total of fifty (50) (25 smoked and 25 dried) fishes were obtained from three markets in Awka and examined microbiologically for viable fungal infestation using Potato Dextrose Agar (PDA) media. A total of 121 fungal organisms were isolated from 25 smoked and 25 dried fish samples and identified. The isolated fungi were Mucor spp, Aspergillus niger, Aspergillus flavus, Penicillium spp, Fusarium spp and Rhizopus spp. It was observed that all the fish samples harboured multiple fungal organisms. Aspergillus niger was the fungus with the highest mean fungal count of 9.00±5.568, followed by Mucor spp (8.00±1.732), while Aspergillus flavus was the lowest (3.67±1.528). In the dried fish samples, Gardus morhua (stock fish) had the highest infestation with fungi (1.08±1.083), while in smoked fish, Clarias gariepinus (catfish) had the highest infestation. The high level of fungal contamination can be attributed to poor handling of fish and the environment. Considering the danger to public health, food and safety authorities should intensify their monitoring efforts towards controlling fish contamination, and fish sellers should also be sensitized on hygienic fish handling techniques.

Distinct food-web transfers of 137Cs to fish in river and lake ecosystems: A case study focusing on masu salmon in the Fukushima evacuation zone

This study was conducted to elucidate the spatial and size variations, and food-web transfer of 137Cs in freshwater fish in the upper reaches of the Ukedo River system, a highly contaminated river system flowing through the Fukushima evacuation zone. Fish collection and environmental surveys were conducted in the summer of 2020 at five forest rivers and at the Ogaki Dam reservoir (an artificial lake) with different air dose rates (mean 0.20–3.32 μSv/h). From the river sites, two salmonid species (masu salmon and white-spotted charr) were sampled, with masu salmon generally exhibiting higher 137Cs concentrations, ranging widely (10.6 Bq/kg-wet to 13.0 kBq/kg-wet) depending on the fish size (size effect) and site. The 137Cs concentrations in masu salmon were explained by the air dose rates, 137Cs concentrations in water, sediments (excluding the lake site), and primary producers, with site-specific variations. In the rivers, masu salmon (fluvial type with parr marks) mainly fed on terrestrial insects with higher 137Cs concentrations compared with those of aquatic insects, indicating that 137Cs was transferred mainly to fish through the allochthonous forest food-web during summer. In the lake, masu salmon (lake-run type with larger size and silvery body coloration) mainly preyed on smaller fish with lower 137Cs concentrations, demonstrating that 137Cs is transferred to fish through the autochthonous lake food-web with biomagnification. Differences in 137Cs concentrations among masu salmon (mean 441 Bq/kg-wet) and other fish species (mean 74.8 Bq/kg-wet to 2.35 kBq/kg-wet) were also found in the lake. The distinct 137Cs transfers to river and lake fish were supported by stable isotope analysis: δ15N and δ13C values enriched stepwisely through the food-webs were, respectively, higher and lower in the lake. Our results obtained using multiple approaches clearly revealed the distinct food-web transfer of 137Cs in river and lake ecosystems. These findings can contribute to prediction of radioactive contamination in freshwater fish in the Fukushima evacuation zone.

Heavy metal contamination in fish: sources, mechanisms and consequences

Heavy metal contamination in fish: sources, mechanisms and consequences

Museum-archived myctophids reveal decadal trends in microplastic and microfiber ingestion

Global plastic production has surged since the 1960s, resulting in the pervasive presence of microplastics in the environment, yet there is a substantial gap in understanding historical trends of plastic pollution in wildlife. Recent discoveries of significant microplastic contamination in fishes have sparked considerable contemporary advancements in analytical methods and hold the potential to fill gaps in historical trends. We measured the presence of microplastics in museum-archived myctophids (Stenobrachius leucopsarus, Diaphus theta, and Tarletonbeania crenularis) collected from 1962 to 2016, to determine if trends in contamination levels over time correspond with the rise in plastics production. Seventy particles were extracted from 57 of the 240 individuals (23.8 % average occurrence across the time series) consisting of primarily blue and black microfibers. Anthropogenically modified cellulose was the dominant material (87 %) identified through μFTIR analysis, with polypropylene and polyethylene particles occurring secondarily. Although the complete time series across a broad geographical range of the North Pacific did not reveal a significant temporal trend, myctophids collected in proximity to the U.S. west coast showed a trend towards increasing incidence of microplastic and microfiber ingestion over time (p ≤ 0.05). Using historical samples of species with higher ingestion levels and consistent collection locations would improve the reliability of future investigations.

Exploring Potential Human Health Risks Linked to Heavy Metal(Loid)s in Dietary Fishes: Utilizing Data-Driven and Computational Modelling Approaches.

There are significant concerns about the risks to human health posed by metal(loid) contamination in dietary fishes in Bangladesh. Therefore, this study aimed to evaluate heavy metal(loid) contamination in fish and their associated health risks using published data from 2000 to 2022. Additionally, the safe limit of fish consumption was estimated using the target hazard quotient (THQ) followed by computational modelling and artificial neural networks (ANN). Results showed that freshwater and herbivorous fishes pose the least non-cancer risks, whereas saltwater and carnivorous fishes pose the highest non-cancer risks to Bangladeshi consumers. However, freshwater and omnivorous fish consumption pose the highest cancer risks compared to all studied metal(loid)s. In particular, among the heavy metal(loid)s, As, Cr, Hg, and Ni pose significant cancer and non-cancer risks to Bangladeshi consumers. On the contrary, the ANN and Decision tree regression (DTR) characterized the dataset, simulation model, or data testing condition, reaching 94.7% accuracy and allowing us to measure the safest fish consumption limit. The herbivorous fishes are less contaminated and allow greater consumption (175.09gday-1). Contrarily, the allowable intake rates of carnivorous and omnivorous fishes are 153.05 and 168.63gday-1, respectively. Besides, the safe consumption rate of saltwater fishes was 156.51gday-1, which was lower than freshwater (180.59gday-1) and euryhaline fishes (182.17gday-1). Therefore, this study will assist fish consumers in selecting less contaminated fish, ensuring safe consumption levels, and ultimately reducing health risks associated with metal(loid) contamination in fish.

Natural radioactivity and heavy metal contamination in edible fish, shellfish and mollusks at the Bay of Bengal, Kuakata, Bangladesh

In this study, gamma activity concentrations, gross alpha and gross beta activity of natural radionuclides, and heavy metal concentrations were measured in eleven edible marine fish, four shellfish, two mollusks, and a common seaweed sample collected from a local sea fish market and sea beach area of the northern part of the Bay of Bengal, Kuakata, Bangladesh. Using HPGe gamma spectrometry, the activity concentrations of 238U, 232Th, and 40K were measured and found to be 19.7 ± 1.5 Bq/kg, 12.2 ± 0.9 Bq/kg, and 188 ± 15 Bq/kg, respectively, with the 232Th concentration surpassing that of 238U. The ZnS scintillation detector was used to assess the gross alpha and gross beta activity. The average gross alpha activity and gross beta activity were found to be 9.4 ± 1.4 Bq/kg and 26 ± 4 Bq/kg, respectively, with the latter attributed to beta emitting radionuclides's abundance. The activity concentrations of 238U, 232Th, and 40K in the analyzed samples varied in the order of Shellfish > Seaweed > Fish > Mollusks, Seaweed > Shellfish > Mollusks > Fish, and Seaweed > Shellfish > Fish > Mollusks. The annual effective dose due to consumption of analyzed seafood was found to be within the world limit of 2400 μSv/y recommended by UNSCEAR. The main contributor to the annual effective dose was 238U. The excess lifetime cancer risk (ELCR) results were below the permissible threshold of 10−3 for radiological risks. Furthermore, average concentrations of Zn and Mn were higher than WHO/FAO recommended values, and carcinogenic Pb, Cd, Cr, and Hg concentrations were below detection limits, according to heavy metal analysis performed by AAS. The average concentration of heavy metals in all of the seafood samples under investigation was in the order of Zn > Fe > Mn. The calculated hazard index (HI), target hazard quotient (THQ), and estimated daily intake (EDI) were compared to the permissible safety limits.

Assessment of Microplastic Pollution in Fresh Fish and Pindang Fish and its Potential Health Hazards in Coastal Communities of Banyuwangi Regency, Indonesia

This study aimed to analyze the microplastic contamination of fresh and pindang fish and its health impact on the coast of Muncar, Banyuwangi Regency, Indonesia. In this study, a total of 115 respondents participated, providing questionnaire data on their fish consumption habits and health problems. Subsequently, spearman’s correlation coefficient, a non-parametric statistical test, was used to analyze the questionnaire data. This study also included 100 samples of marine fish, consisting of 89 fresh fish and 11 pindang fish from various types of marine species. The content of microplastic polymers detected through FTIR (Fourier-Transform Infrared Spectroscopy) was around 3-5 microplastic polymers/fish samples, and the most dominant were Polyethylene, Polyester, Polycaprolactam (Nylon 6) and Polyamide. This study showed that 94 percent of fish samples contained microplastics and only 6 percent of samples did not contain microplastics. The intensity of pindang fish consumption was positively correlated with respondents’ health symptoms and problems. Subsequently, implementing effective waste management systems and educational programs in the coastal areas is crucial in reducing the pollution of seawater resulting from inadequate waste disposal practices.

Chemical speciation of methylmercury and mercury(II) cations in fish by new fluorogenic naphthalimide alkynyl gold complexes: The ultimate test for detecting fish contamination

The proof of concept of a new portable protocol for the detection and speciation of methylmercury and mercury(II) cations in fish samples is described. In this way, traces of methylmercury and/or mercury(II) cations in fish were quantitatively detected using an elaborated protocol and including a fluorescent sensor. In-the-field accurate results were obtained due to the selective behavior of the chemical sensor in the presence of both cations, working at very low concentrations of mercury species in fish under standard laboratory conditions, that are suitable for daily use in ordinary sampling by border companies importing fish or remote laboratories where large devices cannot be carried. The reported fish protocol is useful under real-life conditions for analyzing fish for the presence of methylmercury in contrast to total mercury analysis. The combination of the protocol and the fluorescent reporter constitutes the ultimate test for fish contamination by mercury(II) species in the workplace. The reported limits of detection of 0.72 nM for Hg2+ and 1.62 nM for CH3Hg+ and the closely related values of the two mercury(II) species in fish samples, obtained by ICP-MS analysis and fluorescent measurements, make the method suitable for daily control of methylmercury in fish under the EU legislation parameters and the WHO recommendations.

First Evidence of Microplastic Ingestion by Riverine Fish From the Freshwater of Northwest Peninsular Malaysia.

In a baseline study, we investigated microplastic contamination in fish from the Pinang and Kerian Rivers in Northwest Peninsular Malaysia. In recognition of the growing concern over microplastic pollution in aquatic environments, we aimed to assess the abundance and characteristics of microplastics ingested by various fish species. Fish samples were collected from local fishermen, followed by a digestion process using 10% potassium hydroxide (KOH). Microplastics were isolated and analyzed through visual examination and attenuated total reflectance Fourier transform infrared spectroscopy. The results revealed a high prevalence of microplastics, with Johnius borneensis and Oreochromis sp. exhibiting the highest abundance, averaging 48.6 and 42.8 microplastics/g, respectively. The predominant shapes were fibers (55.6%) and fragments (25.9%), with colors primarily transparent (48.19%) and black (30.12%). Our results indicate significant contamination levels in freshwater fish, emphasizing the need for further research and effective mitigation strategies. These findings provide crucial baseline data on microplastics in Malaysian freshwater ecosystems. Environ Toxicol Chem 2024;43:2189-2198. © 2024 SETAC.

Preliminary Assessment of Mercury and Methyl Mercury Contamination of Sediments, Water and Fish from the Bétaré-oya Gold Extraction Site (Cameroon)

The gold extraction process by mercury amalgamation is recognized worldwide as a process presenting an environmental and health risk linked to mercury contamination of the geo and biosphere close to the gold panning site. The aim of this work is to assess the risk of contamination by mercury of populations living in the locality of Bétaré-oya, which is subject to the phenomenon of small-scale artisanal mining. In order to achieve this, a small social survey was carried out on two gold extraction sites in the locality of Bétaré-oya. Samples of sediment, water and fish were also taken from these sites. After characterization, these samples underwent the total mercury was determined by an automatic mercury analyzer. Moreover, the methyl mercury was extracted from the samples and analyzed by inductively coupled plasma mass spectrometer coupled to gas chromatography and by gas chromatography coupled to an electron capture detector. The results obtained showed total mercury concentrations varying from 386 to 5072 µg/kg in sediments and from 24.6 to 8451 ng/L in water. Methyl mercury was measured at concentrations ranging from 7.62 to 165 µg/kg in sediments, from 2.54 to 15 µg/L and from 45.4 to 90.8 µg/kg in fish. Well water (15.0 ± 2.4 µg/L of methyl mercury) which is consumed by the populations of the study site, and fish contaminated with an average concentration of 68 µg/kg of Methyl mercury, represent the main vectors of the risk of direct contamination of the populations of the locality of Bétaré-oya by this pollutant.

Baseline Study on Microplastic Contamination in Commercial Fish from the Vellar Estuary, South India

Microplastic (MP) contamination has emerged as a serious worldwide issue. Human activity, commercial operations, and fishing are all concentrated around the coast, resulting in high levels of fish MPs contamination. This preliminary investigation aims to examine MP accumulation in commercial fish caught in the Vellar estuary region. Fish samples were collected from the estuary, and MPs in the gills and gastrointestinal tracts of three commercial fish species were analyzed for quantity, type, shape, and color using standard laboratory techniques. MPs particles were found in 2.55-4.35 items per individual fish, with an overall average of 3.2 particles in the gills and 5.5 in the gastrointestinal tract. The majority of the MPs were blue and green fibers with a diameter of 0.5-1 mm. Fragmented pieces of MPs and fibers were abundant in the gut. These findings demonstrated the extent of MPs contamination in Vellar estuary fish tissues, serving as a baseline for MPs loading in the estuary. This study has significant implications for food safety, highlighting the dangers of MPs in fisheries and aquaculture. It also identifies knowledge gaps in the long-term effects of MPs, suggesting a need for further research in this sector.