Behavior and histopathology as biomarkers for evaluation of the effects of paracetamol and propranolol in the neotropical fish species Phalloceros harpagos

Developing an Approach for Integrating Chemical Analysis and Transcriptional Changes to Assess Contaminants in Water, Sediment, and Fish

Pharmaceuticals in aquatic environments pose threats to aquatic organisms because of their continuous release and potential accumulation. Monitoring methods for these contaminants are inadequate, with targeted analyses falling short in assessing water quality's impact on biota. The present study advocates for integrated strategies combining suspect and targeted chemical analyses with molecular biomarker approaches to better understand the risks posed by complex chemical mixtures to nontarget organisms. The research aimed to integrate chemical analysis and transcriptome changes in fathead minnows to prioritize contaminants, assess their effects, and apply this strategy in Wascana Creek, Canada. Analysis revealed higher pharmaceutical concentrations downstream of a wastewater-treatment plant, with clozapine being the most abundant in fathead minnows, showing notable bioavailability from water and sediment sources. Considering the importance of bioaccumulation factor and biota-sediment accumulation factor in risk assessment, these coefficients were calculated based on field data collected during spring, summer, and fall seasons in 2021. Bioaccumulation was classified as very bioaccumulative with values >5000 L kg-1, suggesting the ability of pharmaceuticals to accumulate in aquatic organisms. The study highlighted the intricate relationship between nutrient availability, water quality, and key pathways affected by pharmaceuticals, personal care products, and rubber components. Prioritization of these chemicals was done through suspect analysis, supported by identifying perturbed pathways (specifically signaling and cellular processes) using transcriptomic analysis in exposed fish. This strategy not only aids in environmental risk assessment but also serves as a practical model for other watersheds, streamlining risk-assessment processes to identify environmental hazards and work toward reducing risks from contaminants of emerging concern. Environ Toxicol Chem 2024;43:2252-2273. © 2024 SETAC.

The Antioxidant and Hepatoprotective Potential of Berberine and Silymarin on Acetaminophen Induced Toxicity in Cyprinus carpio L

Berberine (BBR) and silymarin (SM) are natural compounds extracted from plants known for their antioxidant and chemoprotective effects on the liver. The present study aimed to investigate the beneficial properties of BBR and SM and the association of BBR with SM on liver function using fish as "in vivo" models. Moreover, the study investigated their hepatoprotective role after acetaminophen (APAP) exposure. For this purpose, the fish (N = 360; 118.4 ± 11.09 g) were fed with control or experimental diets for 9 weeks. In the experimental diets, the feed was supplemented with either SM (1 g/kg feed), BBR (100 and 200 mg/kg feed), or a combination of BBR with SM (SM 1 g/kg feed + BBR 100 mg/kg feed and, respectively, SM 1 g/kg feed + BBR 200 mg/kg feed). After the feeding trial, seven fish from each tank were randomly selected and exposed to a single APAP dose. The selected serum biochemical markers, oxidative stress markers, and lysozyme activity were used to evaluate the efficiency of the supplements on carp's health profile, particularly regarding the hepatopancreas function. Our results showed that the inclusion of SM and BBR (either as a single or in combination) reduced the serum contents of total cholesterol, triglyceride, and alanine transaminase. An increase in the high-density cholesterol was observed after the administration of BBR or BBR in association with SM. Both supplements showed hepatoprotective activity against APAP-induced hepatotoxicity, especially BBR. The ameliorative effects of SM (1 g) in association with BBR (100 mg) were highlighted by the modulation of the nonspecific immune system and oxidative stress alleviation after APAP exposure.

Multiple biomarker responses in female Clarias gariepinus exposed to acetaminophen

Several authors have documented the presences of acetaminophen (APAP) in both surface and groundwater and have received attention from government agencies and basic authorities across the globe. The impacts of such pharmaceutical products on non-target organism like fish are underestimated as a result of selected investigation using few biomarkers. We evaluated the sub-chronic impacts of APAP in female catfish (Clarias gariepinus) using multiple biomarkers. The exposure of female catfish to APAP induced oxidative stress. Markers such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) were significantly higher in all exposed groups. Exposure of Clarias gariepinus to APAPA caused histological alterations in the gills (fusion and shortening of some filaments, hyperplasia of the epithelial gill cells, aneurism, congestion, and epithelial rupture of the gills), liver (apoptotic hyperplasia, sinusoidal congestion, and necrosis of the hepatocytes), and gonad (degenerated follicles and ovarian apoptosis). Furthermore, multivariate results indicated that there was a distinct response from the acetaminophen-exposed female catfish, with over 95% of the biomarkers significantly contributing to the discrimination between the acetaminophen-exposed female catfish and the control groups. Our research provides evidence supporting the use of a multiple biomarker approach to evaluate the impacts of drugs on the health status of exposed fish.

Effects of prometryn on oxidative stress, immune response and apoptosis in the hepatopancreas of Eriocheir sinensis (Crustacea: Decapoda)

Prometryn, a triazine pesticide product used to control weed growth, poses a high risk to aquatic organisms in the environment. Several toxicological evaluations have been performed on bony fish and shrimp exposed to prometryn. However, there have been no reports conducted on the toxic mechanism of prometryn with regard to Eriocheir sinensis. In this study, our research evaluated the toxic effects of prometryn via in vitro and in vivo toxicity tests on E. sinensis. Firstly, we estimated the exposure toxicity of prometryn to E. sinensis, and then we constructed a 6 h transcriptional profile and conducted an enrichment analysis. To further reveal the toxicity of prometryn, the hepatopancreas (hepatopancreatic cells) was analyzed for antioxidant, immune and lipid-metabolism-related enzymes, antioxidant- and apoptosis-related gene expression, histopathology and TUNEL. From the results, we determined that the 96 h-LD50 was 70.059 mg/kg, and using RNA-seq, we identified 933 differentially expressed genes (DEGs), which were mainly enriched in the amino and fatty acid metabolism and the cell-fate-determination-related signaling pathway. The results of the biochemical assays showed that prometryn could significantly decrease the activities/levels of CAT, SOD, GSH, AKP and ACP, reduce the levels of T-AOC, TG, TCH, C3 and C4, and increase the MDA content. In addition, the expression levels of Nrf2, GSTs and HO-1 were first upregulated and then downregulated with increasing time. Histopathology showed that prometryn damaged the structure of the hepatopancreas cells and induced apoptosis, suggesting that the PI3K-Akt signaling pathway may be involved in the damage process of hepatopancreas cells (PI3K, PDK and Akt were downregulated whereas Bax was upregulated), leading to their apoptosis. The above results indicated that prometryn could cause injury of the hepatopancreas through oxidative stress, induce cell apoptosis, disrupt the lipid metabolism and cause immune damage. This study provided useful data for understanding and evaluating the toxicity of prometryn to aquatic crustacea.

Short-term effects of various non-steroidal anti-inflammatory drugs (NSAIDs) on Danio rerio embryos

Due to the widespread use of non-steroidal anti-inflammatory drugs (NSAIDs) without a medical prescription and their frequent prevalence in aquatic habitats, there are major health and environmental issues. NSAIDs have been found in surface water and wastewater in concentrations ranging from ng/L to μg/L all over the world. The purpose of this study was to determine the relationship between NSAIDs (diclofenac, ketoprofen, paracetamol and ibuprofen) exposure and associated adverse effects in the assessment of indirect human health risks posed by Danio rerio (zebrafish) and Environmental Risk Assessment (ERA) of these NSAIDs in aquatic environments. Therefore, the objectives of this study were to (i) reveal abnormality endpoints of early developmental stages, after exposure of zebrafish and (ii) perform an ecological risk assessment of aquatic organisms upon exposure to NSAIDs detected in surface waters based on the risk quotients (RQs) method. According to the toxicity data collected, all of the malformations appeared after diclofenac exposure at all concentrations. The most notable malformations were the lack of pigmentation and an increase in yolk sac volume, with EC₅₀ values of 0.6 and 1.03 mg/L, respectively. The results obtained for the ERA revealed RQs higher than 1 for all the four NSAIDs chosen, posing ecotoxicological pressure in aquatic environments. Overall, our findings provide a critical contribution to the formulation of high-priority actions, sustainable strategies and strict regulations that minimize the negative effects of NSAIDs on the aquatic ecosystem.•To determine the LC₅₀, lethal conditions such as coagulation, absence of heartbeat and blood flow, absence of tail separation and development of somites were taken into account.•The EC₅₀ was calculated using sublethal parameters such as blood coagulation, pericardial edema, yolk sac edema or hypertrophy.•The 4 compounds present a high risk individually and in mixture with a RQ >> 1.

Prioritization based on risk assessment to study the bioconcentration and biotransformation of pharmaceuticals in glass eels (Anguilla anguilla) from the Adour estuary (Basque Country, France)

The presence of contaminants of emerging concern in the aquatic environment directly impacts water-living organisms and can alter their living functions. These compounds are often metabolized and excreted, but they can also be accumulated and spread through the food chain. The metabolized contaminants can also lead to the formation of new compounds with unknown toxicity and bioaccumulation potential. In this work, we have studied the occurrence, bioconcentration, and biotransformation of CECs in glass eels (Anguilla anguilla) using UHPLC-HRMS. To select the target CECs, we first carried out an environmental risk assessment of the WWTP effluent that releases directly into the Adour estuary (Bayonne, Basque Country, France). The risk quotients of every detected contaminant were calculated and three ecotoxicologically relevant contaminants were chosen to perform the exposure experiment: propranolol, diazepam, and irbesartan. An experiment of 14 days consisting of 7 days of exposure and 7 days of depuration was carried out to measure the bioconcentration of the chosen compounds. The quantitative results of the concentrations in glass eel showed that diazepam and irbesartan reached BCF ≈10 on day 7, but both compounds were eliminated after 7 days of depuration. On the other hand, propranolol's concentration remains constant all along with the experiment, and its presence can be detected even in the non-exposed control group, which might suggest environmental contamination. Two additional suspect screening strategies were used to identify metabolization products of the target compounds and other xenobiotics already present in wild glass eels. Only one metabolite was identified, nordiazepam, a well-known diazepam metabolite, probably due to the low metabolic rate of glass eels at this stage. The xenobiotic screening confirmed the presence of more xenobiotics in wild glass eels, prominent among them, the pharmaceuticals exemestane, primidone, iloprost, and norethandrolone.

Predicting the impacts of chemical pollutants on animal groups

Chemical pollution is among the fastest-growing agents of global change. Synthetic chemicals with diverse modes-of-action are being detected in the tissues of wildlife and pervade entire food webs. Although such pollutants can elicit a range of sublethal effects on individual organisms, research on how chemical pollutants affect animal groups is severely lacking. Here we synthesise research from two related, but largely segregated fields - ecotoxicology and behavioural ecology - to examine pathways by which chemical contaminants could disrupt processes that govern the emergence, self-organisation, and collective function of animal groups. Our review provides a roadmap for prioritising the study of chemical pollutants within the context of sociality and highlights important methodological advancements for future research.

Low concentrations of ciprofloxacin alone and in combination with paracetamol induce oxidative stress, upregulation of apoptotic-related genes, histological alterations in the liver, and genotoxicity in Danio rerio

Nowadays, there are countless articles about the harmful effects of paracetamol (PCM) in non-target organisms. Nonetheless, information regarding the toxicity of ciprofloxacin (CPX) and the CPX-PCM mixture is still limited. Herein, we aimed to evaluate the hepatotoxic and genotoxic effects that ciprofloxacin alone and in combination with paracetamol may induce in Danio rerio adults. For this purpose, we exposed several D. rerio adults to three environmentally relevant concentrations of PCM (0.125, 0.250, and 0.500 μg/L), CPX (0.250, 0.500, and 1 μg/L), and their mixture (0.125 + 0.250, 0.250 + 0.500, and 0.500 + 1 μg/L) for 96 h. The blood samples showed CPX alone and in combination with PCM damaged the liver function of fish by increasing the serum levels of liver enzymes alanine aminotransferase and alkaline phosphatase. Moreover, our histopathological study demonstrated liver of fish suffered several tissue alterations, such as congestion, hyperemia, infiltration, sinusoidal dilatation, macrovascular fatty degeneration, and pyknotic nuclei after exposure to CPX alone and in combination with PCM. Concerning oxidative stress biomarkers and the expression of genes, we demonstrated that CPX and its mixture, with PCM, increased the levels of antioxidant enzymes and oxidative damage biomarkers and altered the expression of Nrf1, Nrf2, BAX, and CASP3, 6, 8, and 9 in the liver of fish. Last but not least, we demonstrated CPX alone and with PCM induced DNA damage via comet assay and increased the frequency of micronuclei in a concentration-dependent manner in fish. Overall, our results let us point out CPX, even at low concentrations, induces hepatotoxic effects in fish and that its combination with PCM has a negative synergic effect in the liver of this organism.

Ultrastructure and regulation of color change in blue spots of leopard coral trout Plectropomus leopardus

The leopard coral trout generally exhibited numerous round, minute blue spots covering its head (about the size of nostril) and body (except ventral side). This is a characteristic that distinguishes them from similar species. Recently, however, we found the leopard coral trout with black spots. Here, the distribution and ultrastructure of chromatophores in the blue and black spots were investigated with light and transmission electron microscopies. The results showed that in the blue spots, two types of chromatophores are present in the dermis, with the light-reflecting iridophores located in the upper layer and the aggregated light-absorbing melanophores in the lower layer. Black spots have a similar chromatophore composition, except that the melanosomes within the melanophores disperse their dendritic processes to encircle the iridophores. Interestingly, after the treatment of forskolin, a potent adenylate cyclase activator, the blue spots on the body surface turned black. On the other hand, using the skin preparations in vitro, the electrical stimulation and norepinephrine treatment returned the spots to blue color again, indicating the sympathetic nerves were involved in regulating the coloration of blue spots. Taken together, our results revealed that the blue spots of the leopard coral trout can change color to black and vice versa, resulting from the differences in the distribution of melanosomes, which enriches our understanding of the body color and color changes of fishes.

Dangerous connections: biochemical and behavioral traits in Daphnia magna and Daphnia longispina exposed to ecologically relevant amounts of paracetamol

Exposure of nontarget organisms to therapeutic agents can cause distinct toxic effects, even at low concentrations. Paracetamol is a painkiller drug, widely used in human and veterinary therapies, being frequently found in the aquatic compartment in considerable amounts. Its toxicity has already been established for some species, but its full ecotoxicological potential is still not sufficiently described. To characterize the ecotoxicity of paracetamol, the present study evaluated several parameters, such as acute immobilization (EC₅₀ calculation), biochemical alterations, and behavioral effects, in two species of freshwater microcrustaceans of the genus Daphnia (D. magna and D. longispina). To increase the relevance of the data obtained, animals were exposed to levels of paracetamol similar to those already reported to occur in the wild. Data showed antioxidant responses in both species, namely an increase of catalase and GSTs activities in D. magna. On the contrary, effects of paracetamol on D. longispina included only an impairment of GSTs activity. Despite the absence of anticholinesterasic effects, behavioral modifications were also observed. This set of data indicates that realistic levels of paracetamol may trigger the activation of the antioxidant defense system of freshwater crustaceans, causing changes in behavioral traits (increase in swimming time, but with a reduction in swimming distance) of unknown etiology that are likely to affect normal life traits of wild populations.

In vivo toxicities of the hospital effluent in Mahdia Tunisia

Hospital effluent (HE) is one of the most important sources of pharmaceuticals released into the environment. This kind of pollution is a recognized problem for both human health and aquatic life. Consequently, in the present study, we assessed the effects of untreated hospital effluent on mice via biochemical and histopathological determinations. Female mice were given free access to water bottles containing untreated HE at different dilutions for 21 days. Then clinical biochemistry and histopathology evaluation were conducted. Serum biochemistry analysis showed the presence of significant increase in cholesterol, triglycerides, glycaemia and total bilirubin. However, phosphatase alkaline and urea activities have been significantly decreased compared to the control group. No significant variation was observed for the rest of the studied parameters (high-density lipoproteins; low-density lipoproteins and uric acid). Additionally, multiple alterations, including cellular necrosis, leucocyte infiltration and congestion, were observed in different tissues of mice exposed to the tested HE.

Effects of paracetamol on the polychaete Hediste diversicolor: occurrence of oxidative stress, cyclooxygenase inhibition and behavioural alterations

Pharmaceuticals are significant environmental stressors, since they are utilized around the world; they are usually released in to the aquatic system without adequate treatment and several non-target species can be harmed because of their intrinsic properties. Paracetamol is one of the most widely prescribed analgesics in human medical care. Consequently, this compound is systematically reported to occur in the wild, where it may exert toxic effects on non-target species, which are mostly uncharacterized so far. The objective of the present work was to assess the acute (control, 5, 25, 125, 625 and 3125 μg/L) and chronic (control, 5, 10, 20, 40 and 80 μg/L) effects of paracetamol on behavioural endpoints, as well as on selected oxidative stress biomarkers [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRed)] and the anti-inflammatory activity biomarker cyclooxygenase (COX), in the polychaete Hediste diversicolor (Annelida: Polychaeta). Exposure to paracetamol caused effects on behavioural traits, with increased burrowing time (96 h) and hypoactivity (28 days). In addition, exposure to paracetamol resulted also in significant increases of SOD activity, but only for intermediate levels of exposure, but for both acute and chronic exposures. Both forms of GPx had their activities significantly increased, especially after chronic exposure. Acutely exposed organisms had their GRed significantly decreased, while chronically exposed worms had their GRed activity augmented only for the lowest tested concentrations. Effects were also observed in terms of COX activity, showing that paracetamol absorption occurred and caused an inhibition of COX activity in both exposure regimes. It is possible to conclude that the exposure to concentrations of paracetamol close to the ones in the environment may be deleterious to marine ecosystems, endangering marine life by changing their overall redox balance, and the biochemical control of inflammatory intermediaries. Behaviour was also modified and the burrowing capacity was adversely affected. This set of effects clearly demonstrate that paracetamol exposure, under realistic conditions, it not exempt of adverse effects on marine invertebrates, such as polychaetes.

Immunodetection of heat shock protein 70 and cell death in liver of a neotropical fish acutely and chronically exposed to acetaminophen and propranolol

The use of pharmaceutical drugs ends frequently in their inappropriate disposal and treatment at waste water treatment plants, which is the cause of their widespread presence in the environment. Yet, there is limited understanding or knowledge of their effects to non-target aquatic organisms. The drugs acetaminophen (analgesic and antipyretic) and propranolol (β-blocker) are widely found in the aquatic environment, where they can interact with non-target exposed organisms, causing adverse effects. Heat shock proteins (namely HSP70) are molecular chaperones which help to refold misfolded cellular proteins, and the increase in their in vivo levels indicates a change in the cell to counteract the proteotoxic effects of the triggered stress, namely which is consequent to exposure to toxicants. The objective of this study was to quantify the levels of liver HSP70 proteins in individuals of the neotropical fish species Phalloceros harpagos, acutely and chronically exposed to concentrations of acetaminophen and propranolol, in the range of those already determined to occur in the wild. Fish acutely exposed to acetaminophen (concentrations of 8, 80, 800, and 8000 μg L^-1) and to propranolol (levels of 1, 10, and 1000 μg L^-1) evidenced increased intensity of HSP70 immunolabeling in liver cells. Similarly, animals chronically exposed to propranolol, at concentrations of 0.0625, 0.125, 0.25, and 0.5 μg L^-1, showed a comparable trend. This finding suggests the triggering of a cytoprotective effect that was effective in preventing cell death in exposed groups in relation to the control group. In contrast, chronic exposure to acetaminophen caused a decrease in HSP70 labeling intensity in fish hepatocytes (animals exposed to 5, 10, 20, 40, and 80 μg L^-1), with no induction of DNA fragmentation in the nuclei of hepatocytes of these fish. Some of the hepatic HSP70 responses observed in this study were obtained at levels already reported to occur in the wild. Finally, this study showed how levels of acetaminophen at microliter concentration can exert side effects on non-target organisms after chronic exposure, suggesting that environmentally exposed organisms may be subjected to adverse conditions that modify the typical response pattern of HSP70 levels.

Acute and chronic effects of environmental realistic concentrations of simvastatin in danio rerio: evidences of oxidative alterations and endocrine disruptive activity

Due to their wide use, pharmaceuticals can be discarded, metabolized and excreted into the environment, potentially affecting aquatic organisms. Lipid-regulating drugs are among the most prescribed medications around the world, to control human cholesterol levels, in more than 20 million patients. Despite this massive use of lipid-regulating drugs, particularly simvastatin, the role of these drugs is not fully characterized and understood in terms of its potential toxicological effects at the environmental level. This work intended to characterize the toxicity of an acute (120 h post-fertilization) and chronic (60 days) exposure to the antihyperlipidemic drug simvastatin (in concentrations of 92.45, 184.9, 369.8, 739.6 and 1479.2 ng L^-1), in the freshwater species zebrafish (Danio rerio). The concentrations hereby mentioned were implemented in both exposures, and were based on levels found in wastewater treatment plant influents (11.7 ± 3.2 μg L^-1), effluents (2.65 ± 0.8 μg L^-1) and Apies River (1.585 ± 0.3 μg L^-1), located in Pretoria, South Africa and, particularly in the maximum levels found in effluents from wastewater treatment plants in Portugal (369.8 ng L^-1). The acute effects were analysed focusing on behavioural endpoints (erratic and purposeful swimming), total distance travelled and swimming time), biomarkers of oxidative stress (the activities of the enzymes superoxide dismutase, catalase, glutathione peroxidase), biotransformation (the activity of glutathione S-transferases) and lipid peroxidation (levels of thiobarbituric acid reactive substances). Animals chronically exposed were also histologically analysed for sex determination and gonadal developmental stages identification. In terms of acute exposure, significant alterations were reported in terms of behavioural alterations (hyperactivity), followed by a general reduction in all tested biomarkers. Also, the analysis of chronically exposed fish evidenced no alterations in sex ratio and maturation stages. In addition, the analysis of chronically exposed fish evidenced no alterations in terms of sexual characteristics, suggesting that the chronic exposure of Danio rerio to simvastatin does not alter the sex ratio and maturation stages of individuals. This assumption suggests that simvastatin did not act as an endocrine disruptor. Moreover, the metabolism, neuronal interactions and the antioxidant properties of SIM seem to have modulated the hereby-mentioned results of toxicity. Results from this assay allow inferring that simvastatin can have an ecologically relevant impact in living organisms.

Cardiovascular drugs and lipid regulating agents in surface waters at global scale: Occurrence, ecotoxicity and risk assessment

Cardiovascular drugs and lipid regulating agents have emerged as major groups of environmental contaminants over the past decades. However, knowledge about their occurrence in freshwaters and their ecotoxicity is still limited. Here, we critically summarize the presence of 82 cardiovascular drugs and lipid regulating agents at a global-scale and represent their effects on aquatic organisms. Only about 71% of these pharmaceuticals in use have been analyzed for their residues in aquatic ecosystems and only about 24% for their effects. When detected in surface waters, they occurred at concentrations of dozens to hundreds of ng/L. In wastewaters, they reached up to several μg/L. Effects of cardiovascular drugs and lipid regulating agents have been extensively studied in fish and a few in invertebrates, such as Daphnia magna and mussels. These pharmaceuticals affect cardiac physiology, lipid metabolism, growth and reproduction. Besides, effects on spermatogenesis and neurobehavior are observed. Environmental risks are associated with beta-blockers propranolol, metoprolol, and lipid lowering agents bezafibrate and atorvastatin, where adverse effects (biochemical and transcriptional) occurred partially at surface water concentrations. In some cases, reproductive effects occurred at environmentally relevant concentrations. This review summarizes the state of the art on the occurrence of cardiovascular drugs and lipid regulating agents at a global-scale and highlights their risks to fish. Further research is needed to include more subtle changes on heart function and to explore non-investigated drugs. Their occurrence in freshwaters and impact on a diverse array of aquatic organisms are particularly needed to fully assess their environmental hazards and risks.

Antioxidative and neurotoxicity effects of acute and chronic exposure of the estuarine polychaete Hediste diversicolor to paracetamol

The presence of anthropogenic drugs in the aquatic ecosystems is a reality nowadays, and a large number of studies have been reporting their putative toxic effects on wildlife. However, the majority of the studies published so far uses standard organisms, whose probability of becoming in contact with drugs in real scenarios of contamination is at least, low. The use of autochthonous organisms in ecotoxicity testing is thus mandatory, and the present study aimed to assess the feasibility of assessing oxidative based stress responses (enzymatic defenses, such as catalase, glutathione-s-transferases, and lipid peroxidation; neurotoxicity as an indirect outcome of oxidizing conditions) on a polychaete species, Hediste diversicolor, after being acutely and chronically exposed to the widely employed drug paracetamol. H. diversicolor showed to be responsive to paracetamol exposure. Data obtained after acute exposure to paracetamol showed that no antioxidant adaptive response was established, but cholinesterasic activity was enhanced. On the contrary, long term exposure of H. diversicolor individuals to paracetamol resulted in clear pro-oxidative effects, with catalase and cholinesterase inhibition, and a significant reduction in the levels of lipoperoxidation. Considering that some of the tested levels (especially those of the chronic test) were already reported in the wild, the here-obtained results are of high environmental significance. In addition, chronic exposure regime yielded more significant results, with important modification of more parameters, suggesting that realistic conditions of exposure are more suited for an integrated assessment of toxicity of drugs in aquatic organisms.

Neurotoxic and respiratory effects of human use drugs on a Neotropical fish species, Phalloceros harpagos

Pharmaceutical drugs are usually and continuously carried to the aquatic environment in different ways. Thus, they are pseudo-persistent in the environment, and they may exert deleterious effects on aquatic organisms. The objective of the present study was to investigate the acute and chronic effects of two widely used pharmaceutical drugs, paracetamol (analgesic and antipyretic) and propranolol (β-blocker) on the activity of specific biomarkers (namely cholinesterase enzymes and lactate dehydrogenase) of the neotropical fish Phalloceros harpagos. The obtained results indicate an inhibition of the activity of the enzyme lactate dehydrogenase (LDH) after acute exposure to paracetamol, and an increase in cholinesterase activity in acutely propranolol-exposed fish. Chronic exposure to both drugs did not modify the enzymatic activities. Such short-term changes in enzymatic activities may be harmful to organisms, altering the preferential pathway of energy metabolism, and may induce behavioral changes that may compromise prey capture and predator escape, and in the longer term may induce population declines.

Effects of common pharmaceutical drugs (paracetamol and acetylsalicylic acid) short term exposure on biomarkers of the mussel Mytilus spp

Pharmaceutical drugs in the wild may pose significant risks to non-target exposed organisms. This situation is even more troublesome for coastal marine or estuarine environments, located in the vicinity of large human conglomerates, for which the putative number of pollutants is extremely high, and the regime by which wild organisms are exposed is continuous. In addition, the number of studies addressing this issue is still scarce, despite evidences that show the potential contamination profiles and adverse biological effects in organisms from such areas. In this study, the ecotoxicity of common pharmaceutical drugs (namely paracetamol and acetylsalicylic acid) was assessed, by studying the susceptibility of the mussel species Mytilus spp to oxidative stress after being exposed for 96 h to increasing but ecologically relevant concentrations of the two mentioned pharmaceuticals (paracetamol: 0, 0.5, 5, 50, and 500 μg/L; acetylsalicylic acid: 0, 0.1, 1, 10, and 100 μg/L). The oxidative status in exposed organisms was analyzed by measuring oxidative stress biomarkers, namely catalase (CAT), glutathione-S-transferases (GSTs), and lipoperoxidation (LPO) levels, whose alteration was indicative of chemical exposure, in both digestive gland and gills of the organisms. In addition, the food uptake and the nutritional reserve status of exposed organisms were also assessed, by measuring the consumption of ingested food, and levels of tissue reserves of glycogen in gills and digestive gland. No significant alterations were observed in the assessed oxidative stress parameters so it was possible to hypothesize that the studied drugs may have probably exerted a limited alteration of antioxidant defenses and damage, which was reverted by the activation of defensive adaptive mechanisms. This set of data evidenced that the pro-oxidative metabolism that was already described for both drugs in other animal models, was not fully established in the exposed mussels. On the contrary, glycogen reserves were substantially changed after exposure to both toxicants, being possible to observe opposite responses caused by both drugs. Food uptake was not altered following exposure to the drugs. Further evaluations are thus required to conclude about both drugs ecotoxicity and other parameters, namely seasonality, which should be considered when performing ecotoxicology tests, especially with the selected species.

Behavioral and biochemical effects of the antifouler and antidandruff zinc pyrithione on the freshwater fish Gambusia holbrooki

The presence of pharmaceutical residues in the aquatic environment is receiving great attention since the levels of these substances have significantly increased in this compartment, potentially leading to adverse ecological effects. Zinc pyrithione (ZnPt) is a widely used organometallic biocide, which is incorporated into antifouling formulas, such as paints, to prevent the establishment of biofilms on surfaces exposed to the aquatic environment. It is also used in cosmetics, such as antidandruff shampoos and soaps. Considering this wide use, and the absence of a significant amount of data on the toxicity of ZnPt especially towards non-target organisms, the objective of this study was to characterize the toxicity of ZnPt, on several ecological relevant endpoints assessed in the fish Gambusia holbrooki. For this purpose, we measured traits related to feeding and aggressive behavior, as well as indicators of oxidative stress (CAT and GSTs), neurotoxicity (AChE), and anaerobic metabolism (LDH), after acute and chronic exposures to ZnPt. In terms of behavioral features, the feeding test showed the occurrence of significant differences between the control animals and those exposed to a concentration of ZnPt of 45 μg/L. In addition, ZnPt caused changes in terms of oxidative stress biomarkers (CAT and GSTs), for both exposure periods. ZnPt was also capable of causing changes in the cholinergic neurotransmission functioning and anaerobic metabolism, but only following the chronic exposure.

Effects of commonly used therapeutic drugs, paracetamol, and acetylsalicylic acid, on key physiological traits of the sea snail Gibbula umbilicalis

Over time, the consumption of pharmaceutical drugs has highly augmented, directly contributing for an increase of the discharges of these substances into sewage water due to excretion, and their direct release to the environment, with or without adequate treatment. Considering that part of the sewage water is dumped into rivers and seas, this is the major source of contamination of the aquatic environment. Paracetamol and acetylsalicylic acid are among the most worldwide consumed pharmaceutical drugs, frequently found in wastewater discharges and consequently in the aquatic environment in considerable amounts, posing ecotoxicity concerns especially towards aquatic non-target species. Thus, it is important to study the ecotoxicological implications that these drugs might pose to organisms from aquatic environments. The objective of this study was to assess the toxic effects of these two compounds on key biochemical features (antioxidant defenses and damage, metabolism, and cholinergic neurotoxicity) of the marine snail species Gibbula umbilicalis after an acute (96 h) exposure, simulating pulses of contamination. In order to understand the effects that those drugs have on this species, the biochemical biomarkers analyzed were the activities of catalase (CAT), glutathione-S-transferases (GSTs), cholinesterases (ChEs), and the levels of lipid peroxidation (TBARS). After acute exposure to paracetamol, catalase activity decreased significantly in organisms exposed to both highest concentrations; no significant alterations were observed for glutathione-S-transferases activity; TBARS concentration decreased significantly in organisms exposed to the intermediate and both highest concentrations, and cholinesterase activity increased significantly in animals exposed to the lowest concentration. However, after acute exposure to acetylsalicylic acid, catalase activity increased significantly; no significant alterations were observed for glutathione-S-transferases activity, and TBARS concentrations and cholinesterase activity increased. This set of data shows that G. umbilicalis is highly responsive to the presence of the tested drugs, and may thus be a promising species to serve as test organism in future marine ecotoxicological testing. The adoption of this species may broaden the offer of highly ecologically representative test organisms to be included in biomonitoring projects of the coastal and marine environment. Furthermore, it is possible to suggest that both drugs may pose significant deleterious effects of pro-oxidative origin to the physiology of the selected species, with potential adverse ecological consequences, even after short periods of exposure. The absence of neurotoxicity showed that despite being able to trigger antioxidant mechanisms, both drugs did not affect neurotransmission.

Acute and chronic effects of paracetamol exposure on Daphnia magna: how oxidative effects may modulate responses at distinct levels of organization in a model species

The modern usage of pharmaceutical drugs has led to a progressive increase in their presence and environment concentrations, particularly in the aquatic compartment which is the most common final dumping location for this specific class of chemicals. These substances, due to their chemical and biological properties, can exert mostly uncharacterized toxic effects to non-target aquatic species, given the diverse pathways they activate, and the large number of putative targets in the wild. Among drugs in the environment, paracetamol assumes a leading role, considering its widespread therapeutic use and consequently, environmental presence. The present study aimed to assess the acute and chronic effects of paracetamol, in ecologically relevant levels, in the freshwater cladoceran Daphnia magna, namely focusing on biochemical and reproductive parameters. Considering the pro-oxidant effects of paracetamol, already described for a large set of aquatic organisms, specific enzymes involved in the anti-oxidant and metabolic responses were quantified, namely catalase (CAT) and glutathione S-transferases (GSTs) activities. Cholinesterases (ChEs) activity was quantified to evaluate the capacity of paracetamol to induce neurotoxicity, an indirect outcome of oxidative effects by paracetamol, that may affect feeding behavior and reproductive outcomes of this crustacean. Paracetamol in the tested levels showed no effect on reproductive traits of D. magna. Results obtained for organisms acutely exposed included significant increases in the activities of both GSTs and CAT, demonstrating a short-term pro-oxidative effect by paracetamol. On the contrary, ChEs activity was significantly decreased in organisms exposed to this drug, showing a possible interference with neurotransmission. On the contrary, no noteworthy effects were reported for organisms chronically exposed to ecologically realistic concentrations, evidencing the transient nature of the obtained biological response. These results demonstrate the responsiveness of D. magna to paracetamol, especially for high levels of exposure that, despite not being environmentally relevant, are able to trigger significant antioxidant responses. No population effects were likely to be caused by realistic levels of paracetamol, and the absence of biochemical changes after chronic exposure suggests that this specific organism may not be deleteriously affected by low levels of paracetamol, under real scenarios of contamination.