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Highlights: [•] Metals are widespread in the aquatic compartment due to anthropogenic activities. [•] Metals can cause important anticholinesterasic effects in fish, already documented. [•] Metals Pb, Cu Zin and Cd did not significantly impair cholinesterases of G. holbrooki. [•] The role of ChE inhibition in the analysis of metal toxicity must be reconsidered. [Copyright &y& Elsevier]

Cerium oxide nanoparticles (CeO 2 -NP) have already been detected in the aquatic compartment, however, the evaluation of potential ecotoxicological effects on biota are scarce. The present study aimed to assess the toxic effects of CeO 2 -NP in Oncorhynchus mykiss in different organs/tissues (gills, liver and kidney) after acute exposure (96 h) to three concentrations: 0.25, 2.5 and 25 mg/L. Oxidative stress response (catalase - CAT; glutathione S-transferases - GSTs), lipid peroxidation (thiobarbituric acid reactive substances - TBARS), Na+/K+-ATPase activity, genotoxicity (genetic damage index - GDI) and histopathology (organ's pathological indices) were evaluated. CAT activity was increased in gills and decreased in liver of fish exposed to the highest CeO 2 –NPs concentration tested. However, GSTs and Na+/K+-ATPase activities and TBARS levels were not significantly altered in analysed organs. CeO 2 –NP caused marked changes in the gills (aneurysms, blood capillary congestion, lamellar hypertrophy and hyperplasia, secondary lamella fusion and epithelial lifting), in liver (pyknotic nucleus, hyperemia, enlargement of sinusoids and leucocyte infiltration) and kidney (shrinkage of the glomeruli, enlargement of the Bowman space, tubular degeneration and nuclear hypertrophy). Moreover, a semi-quantitative histopathological scoring system (pathological index) confirmed significant alterations in the three organs of all exposed fish. Furthermore, a significant increase of GDI indices observed in gills and liver, for all tested concentrations, indicated a dose-dependent effect. The present study suggests that the release of CeO 2 -NP into the aquatic environment promotes biochemical, genotoxic and histopathological damages in fish. However, the mechanisms underlying the occurrence of such effects require further investigation. Unlabelled Image • Ecotoxicological effects on the aquatic biota of Cerium oxide nanoparticles (CeO 2 -NP) is scarce. • Results showed that the CeO 2 -NP promotes biochemical, genotoxic and histopathological damages in fish. • The mechanisms underlying the occurrence of such effects require further investigation. [ABSTRACT FROM AUTHOR]

This study assessed the occurrence and ecological potential risk of nine selected pharmaceuticals in water samples from the Juquehy River. The river flows continuously to Juquehy Beach, known as "the jewel of the north coast" of São Paulo, Brazil. Samples were collected during Christmas and the New Year (period of December 2023–January 2024), in addition to a previous baseline weekend, to compare the loads during "celebratory parties" versus "normal operational conditions." The findings indicated that the "mass gathering" during Christmas and New Year holidays contributed significantly to an increase of the mass load of the nine pharmaceuticals flowing along to the Juquehy River, i.e., caffeine (14.40–633.00 ng/L) > losartan ( furosemide (< LOQ to 9.16 ng/L) > diclofenac (0.61–4.55 ng/L) > carbamazepine (< LOQ to 0.73 ng/L) > orphenadrine (< LOQ to 0.11 ng/L) showed higher concentrations during the New Year holiday. Conversely, atenolol (< LOQ to 13.10 ng/L) > benzoylecgonine (0.33–7.23 ng/L) > cocaine (0.12–6.59 ng/L) showed higher concentrations during the Christmas day. The individual ecological risk assessment in the Juquehy River revealed a clear environmental concern for the aquatic ecosystem. The threat to the aquatic biota is significant, with caffeine and losartan presenting a moderate level of risk. Moreover, the mixture ecological risk assessment of nine compounds indicates acute moderate risks to algae, crustaceans, and fishes, as well as chronic low risks to fishes. [Display omitted] • The seasonal variation of pharmaceuticals in a Brazilian beach was monitored. • Load variations could be related to the habits and number of consumers. • New Year holiday was associated with the highest concentration of pharmaceuticals. • Significant detection of caffeine regardless the day of the week. • Ecological risks were mainly driven by losartan > caffeine > cocaine. [ABSTRACT FROM AUTHOR]

Intersex gonads have been observed in thicklip grey mullet Chelon labrosus , inhabiting estuaries with high burdens of xenoestrogens in the Southeast Bay of Biscay, but knowledge of population connectivity among estuaries is lacking for this euryhaline fish species. This study investigates the population structure of C. labrosus using otolith shape and elemental signatures of 60 adults (overall length ∼ 38 cm) from two estuaries 21 nautic miles apart, one with a high incidence of intersex condition (Gernika), and the other one pristine (Plentzia). Otolith shape analyses were performed using elliptical Fourier descriptors, while elemental signatures of whole sagittae were obtained by inductively coupled plasma mass spectrophotometry. Univariate and multivariate statistics were applied to determine if otolith signatures show patterns of homogeneity between estuaries. The data indicated significant differences in the otolith shape and elemental composition between mullets of Gernika and Plentzia. Elemental differences were mainly driven by Sr, Li (both higher in Plentzia) and Ba (higher in Gernika). The 98% re-classification success rate obtained from stepwise linear discriminant function analysis suggests that Gernika and Plentzia individuals form separated population units. The limited connectivity between these two close estuaries would indicate a different life history of exposure to chemicals, which might explain the high prevalence of intersex condition in Gernika and its absence in Plenztia. • Population connectivity was studied in Chelon labrosus from two Basque estuaries. • Otolith shape and composition were studied to understand population structure. • Mullets from Gernika and Plentzia showed significant differences in otolith shape. • Significant differences in Sr, Li and Ba were found in otoliths of both estuaries. • Thicklip grey mullets form separated population units in two nearby estuaries. [ABSTRACT FROM AUTHOR]

Alterations of the physical-chemical properties of the oceans due to anthropogenic activities are, at present, one of the most concerning environmental issues studied by researchers. One of these issues is ocean acidification, mainly caused by overproduction and release of carbon dioxide (CO 2) from anthropogenic sources. Another component of environmental degradation is related to the production and release of potential toxic compounds, namely active pharmaceutical ingredients, into the aquatic environment that, combined with oceanic acidification, can cause unpredictable and never before considered deleterious effects on non-target marine organisms. Regarding this issue, the hereby study used predictions of future ocean acidification to simulate realistic scenarios of environmental exposure to a common therapeutic drug, salicylic acid (SA), in the marine gastropod Gibbula umbilicalis under different pH values. This species was exposed to a range of pH values (8.2, 7.9 and 7.6), and to already reported environmentally realistic concentrations (5, 25 and 125 μg/L) of SA. To evaluate the effects of these environmental stressors, key physiological biomarkers (GSTs, CAT, TBARS, AChE and COX) and shell hardness (SH) were quantified. Results from the present study showed that CAT and GSTs activities were enhanced by SA under water acidification; increased lipid peroxidation was also observed in organisms exposed to SA in more acidic media. In addition, the hereby study demonstrated the neurotoxic effects of SA through the inhibition of AChE. Effects were also observed in terms of COX activity, showing that SA absorption may be affected by water acidification. In terms of SH, the obtained data suggest that SA may alter the physical integrity of shells of exposed organisms. It is possible to conclude that the combination of seawater acidification and exposure to toxic xenobiotics (namely to the drug SA) may be strenuous to marine communities, making aquatic biota more susceptible to xenobiotics, and consequently endangering marine life in an unpredictable extent. • Physiological alterations were enhanced under SA exposure at lower pH levels. • Lipid peroxidation increased after seawater acidification. • Neurotoxic effects were reported under SA exposure. • Prostaglandins biosynthesis pathway inhibited by SA absorption at lower pH levels. [ABSTRACT FROM AUTHOR]

Unlabelled Image • Both exposure regimes (waterborne and via feed) to DCF lead to oxidative effects. • These effects occurred at ecologically relevant concentrations of DCF. • Effects were also evident in fish exposed to DCF via contaminated feed. • Environmental levels of DCF may cause changes in the physiology of marine species. [ABSTRACT FROM AUTHOR]