Most tilapias are microphytes, but some prefer higher plants. Ammonia is one of the most important toxic compounds of nitrogen, which is a serious problem in the environment and aquaculture industry. In the present study, juvenile Oreochromis niloticus were exposed to 10, 20, and 30% (96h LC50) of ammonia for two weeks, which are equivalent to 0.9, 1.8, and 2.7 mg / l, respectively. After this period, the fish were anesthetized and blood samples were taken from the caudal stalk with a heparin syringe for evaluating blood indicators. The tissue samples were taken 0.5 cm from the liver, fixed in 10% formalin buffer, and after dehydration with alcohol, clarification with xylol, blocking with paraffin, and cutting 4-6 microns thick with microtome were done. Finally, the stained slides were studied with a light microscope. The results showed phenomena such as hyperemia, nuclear hypertrophy, sinusoidal dilatation, increased melanomacrophage centers, nucleus margination, hepatocyte vacuolation, and cell necrosis in the liver. In the studies of blood serum factors with the increase of ammonia, it has been increased in  AST, ALT, and ALP compared to the control and other groups. Also, as the ammonia concentration increased, the severity of the lesions also increased. Therefore, ammonia causes changes in the structure and activity of metabolic enzymes of the liver, which must be controlled by creating the appropriate ammonia and management conditions in the aquatic environment.

peer reviewed | Microplastics (MPs) are thought to be ingested by a wide range of marine organisms before being excreted. However, several studies in marine organisms from different taxa have shown that MPs and nanoplastics could be translocated in other organs. In this study, we investigated the presence of MPs in the livers of commercial zooplanktivorous fishes collected in the field. The study focuses mainly on the European anchovy Engraulis encrasicolus but concerns also the European pilchard Sardina pilchardus and the Atlantic herring Clupea harengus. Two complementary methodologies were used to attest the occurrence of MPs in the hepatic tissue and to exclude contamination. 1) MPs were isolated by degradation of the hepatic tissue. 2) Cryosections were made on the livers and observed in polarized light microscopy. Both methods separately revealed that MPs, mainly polyethylene (PE), were translocated into the livers of the three clupeid species. In anchovy, 80 per cent of livers contained relatively large MPs that ranged from 124 μm to 438 μm, showing a high level of contamination. Two translocation pathways are hypothesized: (i) large particles found in the liver resulted from the agglomeration of smaller pieces, and/or (ii) they simply pass through the intestinal barrier. Further studies are however required to understand the exact process. © 2017 Elsevier Ltd

Liver disease has become a growing health burden, and little is known about the impairment of liver function caused by exposure to organophosphate esters (OPEs) in adolescents aged 12–19 years in the United States. To investigate the relationship between urinary metabolites of OPEs including diphenyl phosphate (DPHP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis(1-chloroethyl) phosphate (BCPP), bis(2-chloroethyl) phosphate (BCEP), and dibutyl phosphate (DBUP) and liver function in US adolescents aged 12–19 years. Liver function tests (LFTs) include aspartate aminotransferase (AST), albumin (ALB), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin (TBIL), total protein (TP), and AST/ALT. Meanwhile, potential confounding and interaction effects were assessed. The study sample included 592 adolescents aged 12–19 from two consecutive NHANES cycles (2011–2012, 2013–2014). A composite statistical strategy combining traditional linear regression with advanced multi-pollutant models quantile based g-computation (QGC) and eXtreme Gradient Boosting (XGBoost) regression was used to analyze the joint effects of multiple OPEs on liver function indicators, and to describe the interaction between different OPEs in detail. 592 adolescent participants were 15 (14–17) years old, with similar numbers of males and females (304 vs. 288). The analysis results showed that (1) in the linear regression model, individual DPHP, BCEP exposure and ALP changes, BCEP and AST/ALT changes were positively associated. DPHP, BDCPP were negatively associated with TP changes. (2) The combined effects of various OPEs on ALB, ALT, ALP, GGT, TBIL, TP, and AST/ALT were statistically significant. (3) There is no potential interaction between different OPEs. Several OPEs and their combinations are closely related to the 8 LFT indicators. In addition, data suggest that exposure to OPEs in adolescents may be associated with liver damage. Due to limited evidence in the literature and potential limitations of the current study, our findings require more studies to confirm.

A high demand exists in bisphenols (BPs) screening studies for quick, reliable and straightforward analytical methods that generate data faster and simultaneously. Herein, we describe a combination of enzymatic probe sonication (EPS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for quick extraction and simultaneous quantification of eight important BPs in animal-derived foods. Results obtained demonstrated that the ultrasonic probe power could not only enhance the enzymatic hydrolysis efficiency, but also accelerate the liquid-liquid extraction procedure. Under optimized EPS parameters, one sample could be exhaustively extracted within 120 s, as compared with 12 h needed for the conventional enzymatic extraction which is more suitable for high-throughput analysis. The method was successfully applied to analyze residual BPs in animal-derived foods collected from Beijing, China. Widespread occurrence of BPA, BPS, BPF, BPAF, BPP, and BPB were found, with detection frequencies of 65.2%, 42.4%, 33.7%, 29.4%, 28.3%, and 27.2%, respectively. The highest total concentration levels of BPs (sum of the eight BPs analyzed, ΣBPs) were found in chicken liver (mean 12.2 μg/kg), followed by swine liver (6.37 μg/kg), bovine muscle (3.24 μg/kg), egg (2.03 μg/kg), sheep muscle (2.03 μg/kg), chicken muscle (1.45 μg/kg), swine muscle (1.42 μg/kg), and milk (1.17 μg/kg). The estimated daily intake (EDI) of BPs, based on the mean and 95th percentile concentrations and daily food consumptions, was estimated to be 5.687 ng/kg bw/d and 22.71 ng/kg bw/d, respectively. The human health risk assessment in this work suggests that currently BPs do not pose significant risks to the consumers because the hazard index (HI) was <1.

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in aquatic environments and a recent shift toward emerging PFAS is calling for new data on their occurrence and fate. In particular, understanding the determinants of their bioaccumulation is fundamental for risk assessment purposes. However, very few studies have addressed the combined influence of potential ecological drivers of PFAS bioaccumulation in fish such as age, sex or trophic ecology. Thus, this work aimed to fill these knowledge gaps by performing a field study in the Seine River basin (France). Composite sediment and fish (European chub, Squalius Cephalus) samples were collected from four sites along a longitudinal transect to investigate the occurrence of 36 PFAS. Sediment molecular patterns were dominated by fluorotelomer sulfonamidoalkyl betaines (i.e. 6:2 and 8:2 FTAB, 46% of ∑PFAS on average), highlighting the non-negligible contribution of PFAS of emerging concern. C₉–C₁₄ perfluoroalkyl carboxylic acids, perfluorooctane sulfonic acid (PFOS), perfluorooctane sulfonamide (FOSA) and 10:2 fluorotelomer sulfonate (10:2 FTSA) were detected in all fish samples. Conversely, 8:2 FTAB was detected in a few fish from the furthest downstream station only, suggesting the low bioaccessibility or the biotransformation of FTABs. ∑PFAS in fish was in the range 0.22–3.8 ng g⁻¹ wet weight (ww) and 11–140 ng g⁻¹ ww for muscle and liver, respectively. Fish collected upstream of Paris were significantly less contaminated than those collected downstream, pointing to urban and industrial inputs. The influence of trophic ecology and biometry on the interindividual variability of PFAS burden in fish was examined through analyses of covariance (ANCOVAs), with sampling site considered as a categorical variable. While the latter was highly significant, diet was also influential; carbon sources and trophic level (i.e. estimated using C and N stable isotope ratios, respectively) equally explained the variability of PFAS levels in fish.

The Aquidauana River is one of the most important rivers in the Pantanal region, Brazil. However, its waters have been contaminated by nearby anthropogenic activities, threatening native fish species. In this study, our objectives were: 1) to determine the concentrations of Al, As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn in water and sediment samples from the Aquidauana River and to assess the risks posed to aquatic biota; 2) to quantify the concentration of these elements in muscle and liver tissue samples from four native fish species; 3) to evaluate the potential bioaccumulation of inorganic elements in the muscles and liver; and 4) to investigate genotoxicity biomarkers and their association with the inorganic element concentrations present in the muscle tissue. Water and fish samples were collected in November 2020. The concentrations of Al, As, Cd, Cu, Fe, and Pb in the water samples were in disagreement with the Brazilian legislation and presented risks to the aquatic biota. In terms of mixtures of inorganic elements, there was a great increase in the risk to biota. The As concentration did not meet the Brazilian standard for sediments in the sample collected at sampling site 6. The concentrations of Cd and Pb in the muscle tissue of Hypostomus regani, Prochilodus lineatus, Brycon hilarii, and Mylossoma duriventre exceeded the Brazilian standards for human consumption. H. regani showed greater genotoxic damage, and the higher the Al and Fe concentrations in the muscle tissue, the higher the frequencies of lobulated nuclei and nuclear invaginations. Together, our results demonstrate the negative impacts on native fish species from the Aquidauana River contamination and indicate risks to Pantanal biodiversity.

Perfluorooctanesulfonic acid (PFOS) is a persistent anthropogenic chemical that can affect the thyroid hormone system in humans and animals. In adults, thyroid hormones (THs) are regulated by the hypothalamic-pituitary-thyroid (HPT) axis, but also by organs such as the liver and potentially the gut microbiota. PFOS and other xenobiotics can therefore disrupt the TH system at various locations and through different mechanisms. To start addressing this, we exposed adult male rats to 3 mg PFOS/kg/day for 7 days and analysed effects on multiple organs and pathways simultaneously by transcriptomics. This included four primary organs involved in TH regulation, namely hypothalamus, pituitary, thyroid, and liver. To investigate a potential role of the gut microbiota in thyroid hormone regulation, two additional groups of animals were dosed with the antibiotic vancomycin (8 mg/kg/day), either with or without PFOS. PFOS exposure decreased thyroxine (T4) and triiodothyronine (T3) without affecting thyroid stimulating hormone (TSH), resembling a state of hypothyroxinemia. PFOS exposure resulted in 50 differentially expressed genes (DEGs) in the hypothalamus, 68 DEGs in the pituitary, 71 DEGs in the thyroid, and 181 DEGs in the liver. A concomitant compromised gut microbiota did not significantly change effects of PFOS exposure. Organ-specific DEGs did not align with TH regulating genes; however, genes associated with vesicle transport and neuronal signaling were affected in the hypothalamus, and phase I and phase II metabolism in the liver. This suggests that a decrease in systemic TH levels may activate the expression of factors altering trafficking, metabolism and excretion of TH. At the transcriptional level, little evidence suggests that the pituitary or thyroid gland is involved in PFOS-induced TH system disruption.

Per- and polyfluorinated alkyl substances (PFAS) are highly persistent chemicals, which pose a potential risk for aquatic wildlife due to their bioaccumulative behaviour and toxicological effects. Although the distribution of PFAS in marine environments has been studied worldwide, little is known on the contamination of PFAS in the southern North Sea. In the present study, the bioaccumulation and trophic transfer of Perfluoroalkyl acids (PFAAs) was studied in liver and muscle tissue of seven fish species and in whole-body tissue of two crustacean species, collected at 10 sites in the Belgian North Sea. Furthermore, the human and ecological health risks were examined. Overall, perfluorooctane sulfonate (PFOS) was predominant in all matrices and other long-chain PFAS were frequently detected. Mean PFOS concentrations ranged from <LOQ to 107 ng/g (ww) in fish liver, from <LOQ to 24 ng/g ww in fish muscle and from 0.29 to 5.6 ng/g ww in crustaceans. Elevated perfluorotridecanoic acid (PFTrDA) concentrations were detected in fish liver from the estuarine and coastal region (<LOQ-116 ng/g ww), indicating a specific point source of this compound. Based on stable isotope analysis, no distinctive trophic transfer patterns of PFAS could be identified which implies that the bioconcentration of PFAS from the surrounding abiotic environment is most likely dominating over the biomagnification in the studied biota. The consumption of commercially important species such as the brown shrimp (Crangon crangon), plaice (Pleuronecta platessa), sole (Solea solea) and whiting (Merlangus merlangus) might pose potential health risks if it exceeds 17 g/day, 18 g/day, 26 g/day and 43 g/day respectively. Most PFOS measurements did not exceed the QSbᵢₒₜₐ,ₕₕ of 9.1 ng/g ww, however, the benchmark of 33 ng/g ww targeting the protection of wildlife from secondary poisoning was exceeded for 43% and 28% of the samples in plaice and sole.