Effects of waterborne exposure to the antidepressant fluoxetine on swimming, shoaling and anxiety behaviours of the mosquitofish Gambusia holbrooki

Shoal size as a key variable in fish behavioral ecotoxicology: an example using sertraline

A significant limitation of behavioral ecotoxicology is the challenge of obtaining reproducible results due to a wide range of testing conditions. In particular, shoal size affects almost all aspects of fish behavior, but is rarely considered as a factor in ecotoxicological studies. In the present study, we compared the swimming and antipredator responses of different sized shoals of Arabian killifish (Aphaniops stoliczkanus) after exposure to environmentally realistic concentrations of the antidepressant medication sertraline. Groups of fish (1, 3 or 5 individuals) were exposed to either 5 or 50 ng/L sertraline. After 37 days, swimming behavior and responses to a predator alarm were measured. We found that the effects of group size were much stronger than the effects of sertraline on swimming. Group size was also the major factor influencing responses to the predator alarm, with single fish showing the strongest responses. Sertraline directly affected acceleration, turning speed and average distance to the arena wall. For all three parameters, there were significant interactions with shoal size, demonstrating that responses differed depending on the size of the group. We also found that effects of sertraline could still be observed 14 days after cessation of exposure. The study highlights the importance of considering social context and specifically shoal size when designing behavioral studies on chemicals. Failure to consider this may result in over- or under-estimation of risks.

Behavioral biomarkers in fishes: A non-lethal approach to assess the effects of chemical pollution on freshwater ecosystems

The expansion of the human population and the escalating use of chemical products pose a considerable threat to aquatic biodiversity. Consequently, there is an imperative need for the implementation of non-lethal, cost-effective, and easily deployable biomonitoring tools. In this context, fish and their behavior as biomarkers have gained prominence in monitoring of freshwater ecosystems. The aim of this study was to assess the state of art in the use of behavioral biomarkers in ecotoxicology, emphasizing their role as informative tools for global environmental monitoring. Through a systematic literature search, ninety-two articles focusing on the evaluation of behavioral changes in freshwater fish in response to pollution were identified. The most prevalent keywords were "behavior" (7%) and "zebrafish" (6%). Experiments were conducted in countries with expansive territories, such as the United States (18%) and Brazil (17%). Exotic species were primarily employed (58%), with Danio rerio (26%) being the most frequently studied species. Among pollutants, pesticides (32%) and medicines (25%) were the most frequently studied, while locomotion (38%) and social behaviors (18%) were the most frequently evaluated behaviors. Across these studies, authors consistently reported significant changes in the behavior of fish exposed to contaminants, including decreased swimming speed and compromised feeding efficiency. The review findings affirm that evaluating behavioral biomarkers in freshwater fish offers an informative, non-lethal, cost-effective, and easily implementable approach to understanding pollution impacts on freshwater ecosystems. Although few studies on behavioral biomarkers were available to date, the number has rapidly increased in recent years. Furthermore, a variety of novel approaches and study models are being included. Research into behavioral biomarkers is crucial for understanding and managing environmental risks in freshwater ecosystems. Nevertheless, further studies are needed to enhance our understanding of behavioral toxicity indicators, considering factors such as life stage, sex, and breeding season in the tested species.

Toxic Features and Metabolomic Intervention of Glabrene, an Impurity Found in the Pharmaceutical Product of Glabridin

Glabridin is a widely used product in the cosmetics and pharmaceutical industry, which is generally isolated and purified from Licorice (Glycyrrhiza glabra) extract in industrial production. It has wide clinical applications, but significant toxicity has also been reported. The purity of glabridin raw material is generally between 90% and 98%. We have identified a toxic impurity, glabrene, in the industrial product glabridin. Our investigation using an AB wild-type zebrafish toxicity test showed that glabrene has a significant lethal effect with an LC10 of 2.8 μM. Glabrene induced obvious malformation and disrupted cartilage development in zebrafish larvae. Furthermore, the compound significantly reduced larval mobility and caused damage to brain neural tissues. Metabolic pathway analysis and neurotransmitter quantification via ELISA indicated abnormal activation of the phenylalanine metabolic pathway, resulting in elevated dopamine and acetylcholine levels in vivo. These findings provide insights into the potential risks of glabrene contamination and offer a new reference point for enhancing safety measures and quality controls in licorice-derived products.

Pharmaceutical Pollution Alters the Structure of Freshwater Communities and Hinders Their Recovery from a Fish Predator

Freshwater ecosystems are under threat from rising pharmaceutical pollution. While such pollutants are known to elicit biological effects on organisms, we have limited knowledge on how these effects might cascade through food-webs, disrupt ecological processes, and shape freshwater communities. In this study, we used a mesocosm experiment to explore how the community impacts of a top-order predator, the eastern mosquitofish (Gambusia holbrooki), are mediated by exposure to environmentally relevant low (measured concentration: ∼10 ng/L) and high concentrations (∼110 ng/L) of the pervasive pharmaceutical pollutant fluoxetine. We found no evidence that exposure to fluoxetine altered the consumptive effects of mosquitofish on zooplankton. However, once mosquitofish were removed from the mesocosms, zooplankton abundance recovered to a greater extent in control mesocosms compared to both low and high fluoxetine-exposed mesocosms. By the end of the experiment, this resulted in fundamental differences in community structure between the control and fluoxetine-treated mesocosms. Specifically, the control mesocosms were characterized by higher zooplankton abundances and lower algal biomass, whereas mesocosms exposed to either low or high concentrations of fluoxetine had lower zooplankton abundances and higher algal biomass. Our results suggest that fluoxetine, even at very low concentrations, can alter aquatic communities and hinder their recovery from disturbances.

Parental exposure to antidepressants has lasting effects on offspring? A case study with zebrafish

Fish have common neurotransmitter pathways with humans, exhibiting a significant degree of conservation and homology. Thus, exposure to fluoxetine makes fish potentially susceptible to biochemical and physiological changes, similarly to what is observed in humans. Over the years, several studies demonstrated the potential effects of fluoxetine on different fish species and at different levels of biological organization. However, the effects of parental exposure to unexposed offspring remain largely unknown. The consequences of 15-day parental exposure to relevant concentrations of fluoxetine (100 and 1000 ng/L) were assessed on offspring using zebrafish as a model organism. Parental exposure resulted in offspring early hatching, non-inflation of the swimming bladder, increased malformation frequency, decreased heart rate and blood flow, and reduced growth. Additionally, a significant behavioral impairment was also found (reduced startle response, basal locomotor activity, and altered non-associative learning during early stages and a negative geotaxis and scototaxis, reduced thigmotaxis, and anti-social behavior at later life stages). These behavior alterations are consistent with decreased anxiety, a significant increase in the expression of the monoaminergic genes slc6a4a (sert), slc6a3 (dat), slc18a2 (vmat2), mao, tph1a, and th2, and altered levels of monoaminergic neurotransmitters. Alterations in behavior, expression of monoaminergic genes, and neurotransmitter levels persisted until offspring adulthood. Given the high conservation of neuronal pathways between fish and humans, data show the possibility of potential transgenerational and multigenerational effects of pharmaceuticals' exposure. These results reinforce the need for transgenerational and multigenerational studies in fish, under realistic scenarios, to provide realistic insights into the impact of these pharmaceuticals.

The impact of heavy metal concentrations on aquatic insect populations in the Asan Wetland of Dehradun, Uttarakhand

This study, centered on the Asan Wetland in Uttarakhand, examines the ecological impact of heavy metals on aquatic insects biodiversity. It highlights the detrimental effects of metals like chromium, mercury, and lead, stemming from natural and anthropogenic sources, on aquatic insects diversity. Aquatic insects, particularly sensitive to water quality, are emphasized as key indicators of environmental health, illustrating the importance of understanding and managing the influences on wetland ecosystems. Wetland ecosystems are vulnerable to various environmental stressors, including pollution from heavy metals. These toxic substances can alter water quality parameters, disrupt nutrient cycling, and negatively impact the biodiversity and ecological balance of the system. This study aimed to evaluate the impact of several heavy metals (namely Cd, As, Cu, Fe, Pb, Ni, Zn, Al, Cr) on the distribution and biodiversity of various aquatic insect species, including Coeleoptera, Diptera, Ephemeroptera, Odonata, Plecoptera, and Trichoptera. The research utilized data collected between November 2021 and October 2022 from specifically chosen sites (S1, S2, S3) within the Asan Wetland in Dehradun, Uttarakhand. After collecting and identifying samples, various statistical (Sorenson, Shannon-Weiner diversity index, Margelef index) and multivariate tests (CCA, PCA, One-way Anova), have been applied to show the effects of these parameters. This study offers significant findings regarding the distribution patterns of heavy metals, the abundance of aquatic insects, and their interconnectedness within the ecosystem of the Asan Wetland. The abundance of aquatic insects, represented by 13 genera belonging to 6 orders, was assessed at three different sites (S1, S2, and S3) within the wetland. It was concluded that the heavy metals concentration and aquatic insects' density increases and decreases vice-versa in monsoon and winter seasons might be due to unfavourable factors. These findings contribute to the understanding of ecological dynamics and potential impacts of heavy metals on aquatic biota in wetland environments.

Evaluation of Tacrolimus' Adverse Effects on Zebrafish in Larval and Adult Stages by Using Multiple Physiological and Behavioral Endpoints

Tacrolimus (FK506) is a common immunosuppressant that is used in organ transplantation. However, despite its importance in medical applications, it is prone to adverse side effects. While some studies have demonstrated its toxicities to humans and various animal models, very few studies have addressed this issue in aquatic organisms, especially zebrafish. Here, we assessed the adverse effects of acute and chronic exposure to tacrolimus in relatively low doses in zebrafish in both larval and adult stages, respectively. Based on the results, although tacrolimus did not cause any cardiotoxicity and respiratory toxicity toward zebrafish larvae, it affected their locomotor activity performance in light-dark locomotion tests. Meanwhile, tacrolimus was also found to slightly affect the behavior performance, shoaling formation, circadian rhythm locomotor activity, and color preference of adult zebrafish in a dose-dependent manner. In addition, alterations in the cognitive performance of the fish were also displayed by the treated fish, indicated by a loss of short-term memory. To help elucidate the toxicity mechanism of tacrolimus, molecular docking was conducted to calculate the strength of the binding interaction between tacrolimus to human FKBP12. The results showed a relatively normal binding affinity, indicating that this interaction might only partly contribute to the observed alterations. Nevertheless, the current research could help clinicians and researchers to further understand the toxicology of tacrolimus, especially to zebrafish, thus highlighting the importance of considering the toxicity of tacrolimus prior to its usage.

Impact of environmentally relevant concentrations of fluoxetine on zebrafish larvae: From gene to behavior

Fluoxetine is widely prescribed for the treatment of depressive states, acting at the level of the central nervous system, consequently affecting non-target organisms. This study aimed to investigate the influence of environmentally relevant fluoxetine concentrations (1-1000 ng/L) on Danio rerio development, assessing both embryotoxicity and behavior, antioxidant defense, gene expression and neurotransmitter levels at larval stage. Exposure to fluoxetine during early development was found to be able to accelerate embryo hatching in embryos exposed to 1, 10 and 100 ng/L, reduce larval size in 1000 ng/L, and increase heart rate in 10, 100 and 1000 ng/L exposed larvae. Behavioral impairments (decreased startle response and increased larvae locomotor activity) were associated with effects on monoaminergic systems, detected through the downregulation of key genes (vmat2, mao, tph1a and th2). In addition, altered levels of neurochemicals belonging to the serotonergic and dopaminergic systems (increased levels of tryptophan and norepinephrine) highlighted the sensitivity of early life stages of zebrafish to low concentrations of fluoxetine, inducing effects that may compromise larval survival. The obtained data support the necessity to test low concentrations of SSRIs in environmental risk assessment and the use of biomarkers at different levels of biological organization for a better understanding of modes of action.

Are early and young life stages of fish affected by paroxetine? A case study with Danio rerio

Paroxetine (PAR) is a selective serotonin reuptake inhibitor (SSRI) antidepressant increasingly detected in surface waters worldwide. Its environmental presence raises concerns about the potential detrimental effects on non-target organisms. Thus, this study aimed to increase knowledge on PAR's potential environmental impacts, assessing the effects of commercial formulation (PAR-c) and active ingredient (PAR-a) on fish. Therefore, the short-term exposure effects of PAR-c and PAR-a were assessed on zebrafish (Danio rerio) embryos/larvae to determine the most toxic formulation [through median lethal (LC50) and effective concentrations (EC50)]. PAR-c and PAR-a induced morphological abnormalities (scoliosis) in a dose-dependent manner from 96 hours post-fertilization onwards, suggesting the involvement of a fully functional biotransformation system. As PAR-c exhibited higher toxicity, it was selected to be tested in the subsequent stage (juvenile stage), which was more sensitive (lower LC50). PAR-c significantly decreased fish swimming activity and disrupted fish stress response. Overall, the results highlight the ability of PAR-c to adversely affect fish swimming performance, an effect that persisted even after exposure ceases (21-day depuration), suggesting that PAR-c may impair individual fitness.

Nanosilica and copper ecotoxicity in Gambusia holbrooki fish

When silica nanoparticles (SiNP) reach the water bodies interact with the already existing pollutants in the environments. This study aimed to evaluate the ecotoxicity of SiNP under the presence/absence of Cu in mosquitofish (Gambusia holbrooki). Fish were exposed to 0, 10 and 100 mg SiNP L-1, alone or mixed with Cu (0.25 mg L-1). After 96 h, the amount of colony forming units (CFU) of bacteria living on the skin mucus was analysed, and oxidative stress, tissue damage enzymes, and neurotoxicity were evaluated. We observed a reduction in CFU when Cu was present in the media. The liver was the target organ, evidencing a decrease in tissue damage enzymatic activities, activation of the antioxidant system in all treatments, and lipid oxidative damage when the SiNP and Cu were mixed. Overall, SiNP ecotoxicity was proved, which could also be enhanced by the presence of ubiquitous elements such as metals.

Identifying knowledge gaps in understanding the effects of selective serotonin reuptake inhibitors (SSRIs) on fish behaviour

Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants increasingly prescribed to treat patients with clinical depression. As a result of the significant negative impact of the COVID-19 pandemic on the population's mental health, its consumption is expected to increase even more. The high consumption of these substances leads to their environmental dissemination, with evidence of their ability to compromise molecular, biochemical, physiological, and behavioural endpoints in non-target organisms. This study aimed to provide a critical review of the current knowledge regarding the effects of SSRI antidepressants on fish ecologically relevant behaviours and personality-dependent traits. A literature review shows limited data concerning the impact of fish personality on their responses to contaminants and how such responses could be influenced by SSRIs. This lack of information may be attributable to a lack of widely adopted standardized protocols for evaluating behavioural responses in fish. The existing studies examining the effects of SSRIs across various biological levels overlook the intra-specific variations in behaviour and physiology associated with different personality patterns or coping styles. Consequently, some effects may remain undetected, such as variations in coping styles and the capacity to handle environmental stressors. This oversight could potentially result in long-term effects with ecological implications. Data support the need for more studies to understand the impact of SSRIs on personality-dependent traits and how they may impair fitness-related behaviours. Given the considerable cross-species similarity in the personality dimensions, the collected data may allow new insights into the correlation between personality and animal fitness.

Effects of fluoxetine on fish: What do we know and where should we focus our efforts in the future?

Fluoxetine is one of the most studied and detected selective serotonin reuptake inhibitors in the aquatic environment, found at concentrations ranging from ng/L to μg/L. Its presence in this environment can induce effects on aquatic organisms that may compromise their fitness. Several experimental studies have demonstrated that fluoxetine can induce neurotoxicity, genetic and biochemical changes, and cause behavioral dysfunction in a wide range of fish species. However, contradictory results can be found. There is thus the need for a comprehensive review of the current state of knowledge on the effects of fluoxetine on fish at different levels of biological organization, highlighting inclusive patterns and discussing the potential causes for the contradictory results, that can be found in the available literature. This review also aims to explore and identify the main gaps in knowledge and areas for future research. We conclude that environmentally relevant concentrations of fluoxetine (e.g., from 0.00345 μg/L) produced adverse effects and often this concentration range is not addressed in conventional environmental risk assessment strategies. Its environmental persistence and ionizable properties reinforce the need for standardized testing with representative aquatic models, targeting endpoints sensitive to the specific mode of action of fluoxetine, in order to assess and rank its actual environmental risk to aquatic ecosystems.

Temperature modulates the impacts of wastewater exposure on the physiology and behaviour of fathead minnow

Municipal wastewater treatment plant (WWTP) effluent is a substantial source of pollution in aquatic habitats that can impact organisms across multiple levels of biological organization. Even though wastewater effluent is discharged continuously all year long, its impacts across seasons, specifically during winter, have largely been neglected in ecotoxicological research. Seasonal differences are of particular interest, as temperature-driven metabolic changes in aquatic organisms can significantly alter their ability to respond to chemical stressors. In this study, we examined the effects of multiple levels of wastewater effluent exposure (0, 25, or 50% treated effluent) on the physiological and behavioural responses of adult fathead minnow (Pimephales promelas) at temperatures simulating either summer (20 °C) or winter (4 °C) conditions. At 20 °C, wastewater exposure posed a metabolic cost to fish, demonstrated by higher standard metabolic rate and was associated with increased haematocrit and a reduction in boldness. In contrast, fish exposed to wastewater at 4 °C experienced no change in metabolic rate but performed fewer social interactions with their conspecifics. Taken together, our results demonstrate that wastewater exposure can lead to metabolic and behavioural disruptions, and such disruptions vary in magnitude and direction depending on temperature. Our findings highlight the importance of studying the interactions between stressors, while also underscoring the importance of research during colder periods of the year to broaden and deepen our understanding of the impacts of wastewater contamination in aquatic ecosystems.

Chronic Effects of Fluoxetine on Danio rerio: A Biochemical and Behavioral Perspective

Fluoxetine is an antidepressant widely used to treat depressive and anxiety states. Due to its mode of action in the central nervous system (selective serotonin reuptake inhibitor (SSRI)), it becomes toxic to non-target organisms, leading to changes that are harmful to their survival. In this work, the effects of fluoxetine on juvenile zebrafish (Danio rerio) were evaluated, assessing biochemical (phase II biotransformation—glutathione S-transferase (GST), neurotransmission—acetylcholinesterase (ChE), energy metabolism—lactate dehydrogenase (LDH), and oxidative stress—glutathione peroxidase (GPx)) and behavior endpoints (swimming behavior, social behavior, and thigmotaxis) after 21 days exposure to 0 (control), 0.1, 1 and 10 µg/L. Biochemically, although chronic exposure did not induce significant effects on neurotransmission and energy metabolism, GPx activity was decreased after exposure to 10 µg/L of fluoxetine. At a behavioral level, exploratory and social behavior was not affected. However, changes in the swimming pattern of exposed fish were observed in light and dark periods (decreased locomotor activity). Overall, the data show that juvenile fish chronically exposed to fluoxetine may exhibit behavioral changes, affecting their ability to respond to environmental stressors and the interaction with other fish.

Proximate causes and ultimate effects of common antidepressants, fluoxetine and venlafaxine, on fish behavior

Antidepressant (AD) drugs are widely prescribed for the treatment of psychiatric disorders, including depression and anxiety disorders. The continuous use of ADs causes significant quantities of these bioactive chemicals to enter the aquatic ecosystems mainly through wastewater effluent discharge. This may result in many aquatic organisms being inadvertently affected by these drugs. Fluoxetine (FLX) and venlafaxine (VEN) are currently among the most widely detected ADs in aquatic systems. A growing body of experimental evidence demonstrates that FLX and VEN have a substantial capacity to induce neurotoxicity and cause behavioral dysfunctions in a wide range of teleost species. At the same time, these studies often report seemingly contradictory results that are confounding in nature. Hence, we clearly require comprehensive reviews that attempt to find overarching patterns and establish possible causes for these variable results. This review aims to explore the current state of knowledge regarding the neurobehavioral effects of FLX and VEN on fishes. This study also discusses the potential mechanistic linkage between the neurotoxicity of ADs and behavioral dysfunction and identifies key knowledge gaps and areas for future research.

Health Risk Assessment and Levels of Heavy Metals in Farmed Nile Tilapia (Oreochromis niloticus) from the Volta Basin of Ghana

Heavy metals (Pb, Cd, As, Mn, Fe, Zn, Cu, Ni, and Cr) are some of the most toxic elements that can bioaccumulate from sources linked to human activities, such as industry and agriculture. This study quantifies the concentrations of several heavy metals in caged tilapia found in Ghana’s Volta Basin and assesses the associated health risks. The levels of heavy metals in the tissues of Oreochromis niloticus from three cage farms (N = 52) were determined using Atomic Absorption Spectrometry (AAS). The implication for human health was assessed using several risk assessment techniques. Fe (50.11 ± 10.22 mg/kg) and Cr (0.31 ± 0.07 mg/kg) had the highest and lowest accumulated metal concentrations, respectively. Heavy metal concentrations in tilapia tissue from fish farms were ordered as follows: Fe > Mn > Zn > Ni > Cr (farm A), Fe > Zn > Ni > Mn (farm B), and Fe > Mn > Zn > Ni > Cr (farm C). All metals had an estimated daily intake (EDI) below the threshold, and mean differences between sample farms were not statistically significant. Similarly, the values of target hazard quotients (HQs) and hazard indices (HIs) were less than one. According to the risk assessment results, eating tilapia from farms posed no risk to human health. The presence of Mn, Fe, and Ni concentrations above the maximum level in the fish, on the other hand, suggests that they may affect fish health.

Updating the use of biochemical biomarkers in fish for the evaluation of alterations produced by pharmaceutical products

The evaluation of toxic effects in stressful environmental conditions can be determined through the imbalance between exogenous factors (environmental contaminants) and enzymatic and non-enzymatic defenses in biological systems. The use of fish for the identification of alterations in biochemical biomarkers provides a comprehensive vision of the effects that pharmaceutical products cause in the aquatic ecosystem, as they are organisms with high sensitivity to contaminants, filtering capacity, and potential for environmental toxicology studies. A wide range of pharmaceuticals can stimulate or alter a variety of biochemical mechanisms, such as oxidative damage to membrane lipids, proteins, and changes in antioxidant enzymes. This review includes a summary of knowledge of the last 20 years, in the understanding of the different biochemical biomarkers generated by exposure to pharmaceuticals in fish, which include different categories of pharmaceutical products: NSAIDs, analgesics, antibiotics, anticonvulsants, antidepressants, hormones, lipid regulators and mixtures. This review serves as a tool in the design of studies for the evaluation of the effects of pharmaceutical products, taking into account the most useful biomarkers, type of matrix, enzyme alterations, all taking the pharmaceutical group of interest.

Context is Key: Social Environment Mediates the Impacts of a Psychoactive Pollutant on Shoaling Behavior in Fish

Behavior-modifying drugs, such as antidepressants, are increasingly being detected in waterways and aquatic wildlife around the globe. Typically, behavioral effects of these contaminants are assessed using animals tested in social isolation. However, for group-living species, effects seen in isolation may not reflect those occurring in realistic social settings. Furthermore, interactions between chemical pollution and other stressors, such as predation risk, are seldom considered. This is true even though animals in the wild are rarely, if ever, confronted by chemical pollution as a single stressor. Here, in a 2 year multigenerational experiment, we tested for effects of the antidepressant fluoxetine (measured concentrations [±SD]: 42.27 ± 36.14 and 359.06 ± 262.65 ng/L) on shoaling behavior in guppies (Poecilia reticulata) across different social contexts and under varying levels of perceived predation risk. Shoaling propensity and shoal choice (choice of groups with different densities) were assessed in a Y-maze under the presence of a predatory or nonpredatory heterospecific, with guppies tested individually and in male-female pairs. When tested individually, no effect of fluoxetine was seen on shoaling behavior. However, in paired trials, high-fluoxetine-exposed fish exhibited a significantly greater shoaling propensity. Hence, effects of fluoxetine were mediated by social context, highlighting the importance of this fundamental but rarely considered factor when evaluating impacts of environmental pollution.

Occurrence, distribution, and pollution indices of potentially toxic elements within the bed sediments of the riverine system in Pakistan

Potentially toxic elements (PTEs) are a major source of pollution due to their toxicity, persistence, and bio-accumulating nature in riverine bed sediments. The sediment, as the largest storage and source of PTEs, plays an important role in transformation of mercury (Hg), lead (Pb), nickel (Ni), chromium (Cr), copper (Cu), zinc (Zn), and other toxic PTEs. Several important industrial hubs that contain a large population along the banks of different rivers, such as Kabul, Sutlej, Ravi, Jhelum, and Chenab in Pakistan, are acting as major sources of PTEs. In this study, 150 bed sediment samples (n=30 from each river) were collected from different sites. Total (acid extracted) PTE (Hg, Cu, Cr, Ni, Zn, and Pb) concentrations in bed sediments were determined using inductively coupled plasma mass spectrometry (ICP-MS). Sediment pollution indices were calculated in the major rivers of Pakistan. The results demonstrated high levels of Hg and Ni concentrations which exceeded the guideline standards of river authorities in the world. The contamination factor (CF) and contamination degree (CD) indices for Hg, Ni, and Pb showed a moderate to high (CF≥6 and CD≥24) contamination level in all the selected rivers. The values of geo-accumulation index (I_geo) were also high (I_geo≥5) for Hg and Pb and heavily polluted for Ni, while Cr, Cu, and Zn showed low to unpolluted (I_geo) values. Similarly, the enrichment factor (EF) values were moderately severe (5≤EF≤10) for Hg, Pb, and Ni in Sutlej, Ravi, and Jhelum, and severe (10≤EF≤25) in Kabul and Jhelum. Moreover, Hg and Ni showed severe to very severe enrichment in all the sampling sites. The ecological risk index (ERI) values represented considerable, moderate, and low risks, respectively, for Hg (The ERI value should not be bold. Please unbold the  ERI in the whole paper. It should be same like RI, CD and EF. [Formula: see text]≥160), Pb and Ni (40≤[Formula: see text]≤80), and Cr, Cu, and Zn ([Formula: see text]≤40). Similarly, potential ecological risk index (PERI) values posed considerable (300≤RI≤600) risk in Ravi and moderate (150≤RI≤300) in Kabul and Jhelum, but low (RI≤150) risk in Ravi and Chenab. On the basis of the abovementioned results, it is concluded that bed sediment pollution can be dangerous for both ecological resources and human beings. Therefore, PTE contamination should be regularly monitored and a cost-effective and environmentally friendly wastewater treatment plant should be installed to ensure removal of PTEs before the discharge of effluents into the freshwater ecosystems.

Effect of ibuprofen in vivo and in vitro on the sperm quality of the striped catfish Pseudoplatystoma magdaleniatum

Because ibuprofen is a high consumption drug, which has the waters as its final destination, causing alterations in the aquatic environment, specifically in fish. However, there is not enough knowledge about the effect it can have on neotropical fish. This study aimed to evaluate the impact of different concentrations of ibuprofen on sperm quality, both in vivo and in vitro, of the striped catfish Pseudoplatystoma magdaleniatum, and analyze its effects on the reproduction of this critical extinction endangered species. For this purpose, three groups of fish, with a mean weight of 2.3 ± 0.6 kg and mean total length of 62.9 ± 6.1 cm, were placed in tanks (3 fish/tank) with water at concentrations of 0 (control), 25, and 50 μg/L of ibuprofen for 4 months. For the analysis of sperm quality for each treatment (in vivo), the males were selected in the spermiation phase. Also, the semen from the control group was used for in vitro tests and activated with type I water solutions containing 0, 25, and 50 μg/L of ibuprofen. In the in vivo and in vitro tests, when fish and semen were treated to 50 μg/l, the seminal quality of striped catfish was statistically different from the other treatments. For this study, it was shown that ibuprofen at concentrations of 50 μg/L can cause a significant reduction in sperm quality and, therefore, a threat to the reproduction of P. magdaleniatum.

Applications of advanced neuro-behavioral analysis strategies in aquatic ecotoxicology

Despite mounting evidence of pleiotropic ecological risks, the understanding of the eco-neurotoxic impact of most industrially relevant chemicals is still very limited. In particularly the acute and chronic exposures to industrial pollutants on nervous systems and thus potential alterations in ecological fitness remain profoundly understudied. Since the behavioral phenotype is the highest-level and functional manifestation of integrated neurological functions, the alterations in neuro-behavioral traits have been postulated as very sensitive and physiologically integrative endpoints to assess eco-neurotoxicological risks associated with industrial pollutants. Due to a considerable backlog of risk assessments of existing and new production chemicals there is a need for a paradigm shift from high cost, low throughput ecotoxicity test models to next generation systems amenable to higher throughput. In this review we concentrate on emerging aspects of laboratory-based neuro-behavioral phenotyping approaches that can be amenable for rapid prioritizing pipelines. We outline the importance of development and applications of innovative neuro-behavioral assays utilizing small aquatic biological indicators and demonstrate emerging concepts of high-throughput chemo-behavioral phenotyping. We also discuss new analytical approaches to effectively and rapidly evaluate the impact of pollutants on higher behavioral functions such as sensory-motor assays, decision-making and cognitive behaviors using innovative model organisms. Finally, we provide a snapshot of most recent analytical approaches that can be applied to elucidate mechanistic rationale that underlie the observed neuro-behavioral alterations upon exposure to pollutants. This review is intended to outline the emerging opportunities for innovative multidisciplinary research and highlight the existing challenges as well barriers to future development.

Environmentally relevant concentrations of sertraline disrupts behavior and the brain and liver transcriptome of juvenile yellow catfish (Tachysurus fulvidraco): Implications for the feeding and growth axis

Sertraline (SER) is one of the most prevalent antidepressants detected in aquatic environments, but its impact on fish behavior and growth remain poorly understood. As such, behavior and growth were assessed in yellow catfish (Tachysurus fulvidraco) following SER exposure. SER induced shoaling, reduced food consumption and growth, and increased cannibalism at environmentally relevant concentrations. To ascertain toxicity mechanisms, acetylcholinesterase (AChE) activity and transcripts related to growth and feeding were measured. AChE activity was increased in fish exposed to 10 and 100 μg/L SER. Transcript levels of neuropeptide Y, somatostatin, growth hormone, and insulin growth factor 1 were reduced in the brain following SER exposure. RNA-seq conducted in brain and liver revealed that gene networks associated with feeding and growth (i.e. leptin expression networks in the brain and insulin signaling pathways in the liver) were altered, proposed to be associated with the decreased food intake and growth. The brain also accumulated SER, which may relate to neurobehavioral responses. Lastly, the main metabolite of SER, norsertraline, was detected in the liver, and may also relate to toxicity. This study uncovers mechanisms and key events proposed to lead to impaired behavior and growth after exposure to some antidepressants.

Enzymatic activity changes in striped catfish Pseudoplatystoma magdaleniatum, induced by exposure to different concentrations of ibuprofen and triclosan

The present study aimed to evaluate the effects of exposure for four months, with ibuprofen and triclosan at 25 and 50 μg/L in Striped catfish Pseudoplatystoma magdaleniatum, evaluated between sexes and exposure times. Biochemical biomarkers such as lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltransferase, acetylcholinesterase, creatine kinase, lipid peroxidation, albumin, globulins, creatinine, and urea were evaluated. The results of this study suggest that both ibuprofen and triclosan at concentrations of 25 and 50 μg/L can cause alterations to P. magdaleniatum, interfering with the activity of certain enzymes associated with energy production, immune response, architecture, and cellular physiology. Also, we determined the current state of contamination in fish, the concentration of ibuprofen and triclosan in P. magdaleniatum muscle samples from the different places markets located on the banks of the main rivers of Colombia was quantified by UHPLC-QqQ-MS/MS, in three climatic periods; finding triclosan levels in the dry season in some of the sampling points compatible with enzyme-level alterations in this species.

Studies on heavy metals and fish health indicators in Malapterurus electricus from Lekki Lagoon, Lagos, Nigeria

The aquatic ecosystem is constantly being disturbed by rising levels of different classes of pollutants of human origin in the form of urban, agricultural and industrial discharges. In this study, the health of fish Malapterurus electricus was examined, to serve as a reflection of the impact of anthropogenic disturbances in the Lekki lagoon. Eighty six samples of the fish were analysed for parasitic infections, heavy metals, microorganisms in their internal and external body parts while the proximate composition and fish condition factor were also determined using conventional methods. One parasite species, a cestode Electrotaenia malapteruri was found to infect the fish. Total parasite load was eighty five with a total prevalence of infection of 36%. Elements detected in sediment were of the order of Al>Fe>Mn>Pb>Cr>Zn>Cd>Ba>Cu>Ni while in water, it is Mn>Fe>Zn>Ba>Cd>Cr>Al>Cu>Ni>Pb. Metals analysed in the fish tissues were generally low and below regulatory limits. In the proximate analysis, moisture content has a value of 80.7%, while ash content had a value of 1.26%. Eight bacterial and two fungal species were isolated from the fish. The condition factor of fish varied between 1 and 2. The study provides valuable information for monitoring and management of heavy metal pollution in the aquatic ecosystem.

Exposure to silver impairs learning and social behaviors in adult zebrafish

Silver and silver nanoparticles are used in several consumer products, particularly sterilizing agents. Ag⁺ released from the particles causes physiological damages of aquatic organisms. However, the effects of silver on neural and behavioral functions of fish remain unclear. Here, we used zebrafish as a model to investigate the impacts of silver on social, learning and memory behaviors in teleost. Adult zebrafish showed mortality rates of 12.875% and 100% on 72 h exposure to 30 and ≥ 50 ppb of silver nitrate, respectively. Silver accumulation in the brain increased on exposure to 10 and 30 ppb of AgNO₃. The physical fitness of the zebrafish, measured by novel tank diving test and swimming performance, decreased after 72 h incubation in 30 ppb of AgNO₃. Exposure to 10 ppb of AgNO₃ impaired social preference, social recognition, learning, and memory, but did not affect anxiety level, aggressiveness, and shoaling behavior. In situ hybridization of c-fos mRNA showed that AgNO₃ treatment decreased neural activity in the brain areas crucial for learning, memory, and social behaviors, including the medial and dorsal zones of the dorsal telencephalic area. In conclusion, 72 h exposure to AgNO₃ in a sublethal level impaired learning and social behaviors, indicating neurotoxicity in adult zebrafish.

Time-, dose- and transgenerational effects of fluoxetine on the behavioural responses of zebrafish to a conspecific alarm substance

Despite publication of numerous of papers, the effects of fluoxetine on fish behaviour remains mired in controversy and contradiction. One reason for this controversy is that fluoxetine displays distinct and opposing acute and chronic effects. A second reason is that most studies have been limited to two or at the most three concentrations. To address these deficiencies we exposed adult zebrafish, both single females and shoals consisting of one male and two females, to seven fluoxetine concentrations, ranging from 5 ng/L to 5 μg/L and measured their swimming behaviour, and response to a conspecific alarm substance (CAS) at seven, 14 and 28 days. We also measured the light startle response of unexposed F1 larvae at days seven and 28 post-hatch and the response to CAS at day 28. On day 7 fluoxetine decreased swimming speed at concentrations ≥500 ng/L. After addition of CAS fish exposed to 5, 500 and 1000 ng/L decreased swimming, while fish exposed to 10, 500 and 1000 ng/L significantly increased time motionless. On day 14 only fish exposed to 50 ng/L were significantly slower than controls before addition of CAS, but afterwards fish exposed to 5, 50, 1000 and 5000 ng/L showed significant differences from controls. On day 28 fish exposed to 50 and 5000 ng/L had slower average swimming speeds than controls before addition of CAS. After addition all fish except controls and those exposed to 500 ng/L showed decreased average speed. At seven days post-hatch, F1 larvae whose parents were exposed to 100 ng/L showed significantly higher activity than controls and those exposed to 500 ng/L fluoxetine showed lower activity in the light startle response. This study shows that the effects of fluoxetine vary with time and also in a non-monotonic manner. We suggest that the complex nature of the serotonergic system with multilateral effects at the genomic, biochemical and physiological levels interacting with environmental stimuli result in non-linear dose-response behavioural patterns.

Interacting Effects of Polystyrene Microplastics and the Antidepressant Amitriptyline on Early Life Stages of Brown Trout (Salmo trutta f. fario)

Whether microplastics themselves or their interactions with chemicals influence the health and development of aquatic organisms has become a matter of scientific discussion. In aquatic environments, several groups of chemicals are abundant in parallel to microplastics. The tricyclic antidepressant amitriptyline is frequently prescribed, and residues of it are regularly found in surface waters. In the present study, the influence of irregularly shaped polystyrene microplastics (<50 µm), amitriptyline, and their mixture on early life-stages of brown trout were investigated. In a first experiment, the impacts of 100, 104, and 105 particles/L were studied from the fertilization of eggs until one month after yolk-sac consumption. In a second experiment, eggs were exposed in eyed ova stages to 105, 106 particles/L, to amitriptyline (pulse-spiked, average 48 ± 33 µg/L) or to two mixtures for two months. Microplastics alone did neither influence the development of fish nor the oxidative stress level or the acetylcholinesterase activity. Solely, a slight effect on the resting behavior of fry exposed to 106 particles/L was observed. Amitriptyline exposure exerted a significant effect on development, caused elevated acetylcholinesterase activity and inhibition of two carboxylesterases. Most obvious was the severely altered swimming and resting behavior. However, effects of amitriptyline were not modulated by microplastics.

Environmental Fate of Multistressors on Carpet Shell Clam Ruditapes decussatus: Carbon Nanoparticles and Temperature Variation

Ruditapes decussatus is a native clam from the Southern Europe and Mediterranean area, relevant to the development of sustainable aquaculture in these regions. As sessile organisms, bivalves are likely to be exposed to chemical contaminations and environmental changes in the aquatic compartment and are widely used as bioindicator species. Carbon-based nanomaterials (CNTs) use is increasing and, consequently, concentrations of these contaminants in aquatic systems will rise. Therefore, it is imperative to assess the potential toxic effects of such compounds and the interactions with environmental factors such as water temperature. For this, we exposed R. decussatus clams to four different water temperatures (10, 15, 20 and 25 °C) in the presence or absence of CNTs for 96 h. Different parameters related with oxidative stress status, aerobic metabolism, energy reserves and neurotoxicity were evaluated. The relationship and differences among water temperatures and contamination were highlighted by principal coordinates analysis (PCO). CNTs exposure increased oxidative damage as protein carbonylation (PC) in exposed clams at 10 °C. Higher temperatures (25 °C) were responsible for the highest redox status (ratio between reduced and oxidized glutathione, GSH/GSSG) observed as well as neurotoxic effects (acetylcholinesterase—AChE activity). Antioxidant defenses were also modulated by the combination of CNTs exposure with water temperatures, with decrease of glutathione peroxidase (GR) activity at 15 °C and of glutathione S-transferases (GSTs) activity at 20 °C, when compared with unexposed clams. Clams energy reserves were not altered, probably due to the short exposure period. Overall, the combined effects of CNTs exposure and increasing water temperatures can impair R. decussatus cellular homeostasis inducing oxidative stress and damage.

Chinese physicians' attitudes toward eco-directed sustainable prescribing from the perspective of ecopharmacovigilance: a cross-sectional study

INTRODUCTION

Eco-directed sustainable prescribing (EDSP) is an effective upstream way to reduce the environmental footprints of active pharmaceutical ingredients (APIs), a kind of emerging contaminants, from the patients' excretion. EDSP is one of the key steps in the programme of ecopharmacovigilance (EPV), a drug administration route on API pollution.

OBJECTIVE

To assess the attitudes of physicians prescribing medicines regarding EDSP from the perspective of EPV.

DESIGN

A cross-sectional study conducted from March 2019 to June 2019.

SETTING

5 government general hospitals in Hubei province, China.

PARTICIPANTS

405 physicians were randomly selected and 262 valid questionnaires were obtained.

OUTCOME MEASURES

A self-developed questionnaire, which inquired about the participant characteristics, perceptions and attitudes toward API pollution, EPV and EDSP from an EPV perspective, was emailed to collect data from physicians.

RESULTS

Most physicians agreed the existence of APIs in environment, worried about the potential environmental and ecological risks of API residues, supported the effectiveness and necessity of EDSP under an EPV perspective in decreasing environmental exposure of excreted APIs, and showed their willingness to participate in the EDSP practices. Nevertheless, no respondent identified the environmental impacts as the aspects regarding medicines affecting his(her) prescription decision, none was satisfied with knowledge on EDSP and showed confidence toward EDSP. The most important barrier to the effective implementation of EDSP was identified as 'poor awareness of EDSP and EPV'. Most responding physicians (97%) reported that they held the wait-and-see or conservative attitudes towards EDSP practice. The biggest concerns in low-dose prescribing and prescribing of drugs possessing environment-friendly excretion profiles, two EDSP approaches, were the possible negative impact on therapeutic outcomes and too complicated and professional drug evaluation process, respectively.

CONCLUSIONS

Chinese physicians had positive attitudes towards EDSP from the perspective of EPV. However, their environmental consciousness during prescribing and the related education were insufficient.

Immunohistological Biomarkers of Toxicity by a Pharmaceutical Antidepressant in the Freshwater Cichlid Fish Cichlasoma dimerus (Teleostei, Cichliformes)

Melano-macrophage centers (MMCs) are nodular clusters of pigmented macrophages, implicated in homeostasis and destruction and recycling of endogenous and exogenous material. They can increase in size and/or frequency under environmental stress resulting in immunohistological biomarkers of water quality. Fluoxetine (FLX), a commonly prescribed antidepressant, can cause neuroendocrine, behavioral and reproductive alterations in teleost fish. In the present study, we analyzed the effects of a 2-week 50 µg/L FLX exposure on MMCs in histological sections of spleen and head-kidney (HK) of the cichlid fish Cichlasoma dimerus. In the spleen, FLX caused an increase in the area and a decrease in the number of MMCs. An increase in the proportion of the HK occupied by MMCs was observed in FLX-exposed fish, due to an increase in their number but not their area. The deposition rate of MMCs varies according to the hemolymphopoietic organ and would be the result of a differential response to FLX on homeostatic functions (elimination of cellular debris, iron processing and immune response).

Field-realistic antidepressant exposure disrupts group foraging dynamics in mosquitofish

Psychoactive pollutants, such as antidepressants, are increasingly detected in the environment. Mounting evidence suggests that such pollutants can disrupt the behaviour of non-target species. Despite this, few studies have considered how the response of exposed organisms might be mediated by social context. To redress this, we investigated the impacts of two environmentally realistic concentrations of a pervasive antidepressant pollutant, fluoxetine, on foraging behaviour in fish (Gambusia holbrooki), tested individually or in a group. Fluoxetine did not alter behaviour of solitary fish. However, in a group setting, fluoxetine exposure disrupted the frequency of aggressive interactions and food consumption, with observed effects being contingent on both the mean weight of group members and the level of within-group variation in weight. Our results suggest that behavioural tests in social isolation may not accurately predict the environmental risk of chemical pollutants for group-living species and highlight the potential for social context to mediate the effects of psychoactive pollutants in exposed wildlife.

Effects of antidepressants with different modes of action on early life stages of fish and amphibians

Drugs are excreted from the human body as both original substances and as metabolites and enter aquatic environment through waste water. The aim of this study was to widen the current knowledge considering the effects of waterborne antidepressants with different modes of action-amitriptyline, venlafaxine, sertraline-on embryos of non-target aquatic biota-fish (represented by Danio rerio) and amphibians (represented by Xenopus tropicalis). The tested concentrations were 0.3; 3; 30; 300 and 3000 μg/L in case of amitriptyline and venlafaxine and 0.1; 1; 10; 100 and 1000 μg/L for sertraline. Test on zebrafish embryos was carried out until 144 h post fertilization, while test on Xenopus embryos was terminated after 48 h. Lethal and sublethal effects as well as swimming alterations were observed at higher tested concentrations that are not present in the environment. In contrast, mRNA expression of genes related to heart, eye, brain and bone development (nkx2.5, otx 2, bmp4 and pax 6) seems to be impacted also at environmentally relevant concentrations. In a wider context, this study reveals several indications on the ability of antidepressants to affect non target animals occupying environments which may be contaminated by such compounds.

Effects of pollution on freshwater aquatic organisms

This paper presents the reviews of scientific papers published in 2018 issues on the effects of anthropogenic pollution on the aquatic organisms dwelling in freshwater ecosystem at global scale. The first part of the study provides the summary of relevant literature reviews followed by field and survey based studies. The second part is based on categories of different classes/sources of pollutants which affect freshwater organism. This is composed of several sections including metals and metalloids, wastewater and effluents, sediments, nutrients, pharmaceuticals, polycyclic aromatic hydrocarbons, flame retardants, persistent organic pollutants, pharmaceuticals and illicit drugs, emerging contaminants, pesticides, herbicides, and endocrine disruptors. The final part of the study highlights the reviews of published research work on new pollutants such as microplastics and engineered nanoparticles which affect the freshwater organisms. PRACTITIONER POINTS: Heavy metals concentrations should be assessed at nano-scale in aquatic environment. Air pollutants could have long-term effects on freshwater ecosystem. Future studies should focus on bioremediations of freshwater pollution.

Antidepressants in Surface Waters: Fluoxetine Influences Mosquitofish Anxiety-Related Behavior at Environmentally Relevant Levels

Pharmaceutical contamination is an increasing problem globally. In this regard, the selective serotonin reuptake inhibitors (SSRIs)-a group of antidepressants-are particularly concerning. By disrupting the serotonergic system, SSRIs have the potential to affect ecologically important behaviors in exposed wildlife. Despite this, the nature and magnitude of behavioral perturbations resulting from environmentally relevant SSRI exposure among species is poorly understood. Accordingly, we investigated the effects of two field-realistic levels of the SSRI fluoxetine (61 and 352 ng/L) on sociability and anxiety-related behaviors in eastern mosquitofish ( Gambusia holbrooki) for 28 days. Additionally, we measured whole-body tissue concentrations of fluoxetine and norfluoxetine. We found that fluoxetine altered anxiety-related behavior but not sociability. Specifically, female fish showed reduced anxiety-related behavior at the lower treatment level, while males showed an increase at the higher treatment level. In addition, we report a biomass-dependent and sex-specific accumulation of fluoxetine and norfluoxetine, with smaller fish showing higher relative tissue concentrations, with this relationship being more pronounced in males. Our study provides evidence for nonmonotonic and sex-specific effects of fluoxetine exposure at field-realistic concentrations. More broadly, our study demonstrated that neuroactive pharmaceuticals, such as fluoxetine, can affect aquatic life by causing subtle but important shifts in ecologically relevant behaviors.

Biomarker and behavioural responses of an estuarine fish following acute exposure to fluoxetine

Antidepressants such as fluoxetine are frequently detected in estuaries and can have profound effects on non-target organisms by interfering with the neural system and affecting essential physiological processes and behaviours. In this context, short-term effects of fluoxetine exposure were analysed in the common goby Pomatoschistus microps, an estuarine resident fish species. Two experiments were conducted with fish exposed to: i) fluoxetine concentrations within the μg/L range for 96 h (0.1, 0.5, 10 and 100 μg/L) and ii) fluoxetine concentrations within the mg/L range for 1 h (1, 5 and 10 mg/L). Acute toxicity was assessed via multiple biomarker responses, namely: activity levels of antioxidant (superoxide dismutase and catalase) and detoxification enzymes (ethoxyresorufin O-deethylase and glutathione S-transferase); and biomarkers of effects (lipid peroxidation and DNA damage) and of neurotoxicity (acetylcholinesterase inhibition). Furthermore, behavioural responses concerning activity (active time, movement delay and number of active individuals) and feeding (number of feeding individuals) were also recorded and analysed. Acute fluoxetine exposure for 96 h (in the μg/L range) reduced antioxidant CAT activity with increasing concentrations but had no significant effect on SOD activity. Biotransformation enzymes showed bell-shaped response curves, suggesting efficient fluoxetine metabolism at concentrations up to 10 μg/L. No significant damage (LPO and DNAd) was observed at both concentration ranges (μg/L and mg/L), yet 1 h exposure to higher fluoxetine concentrations (mg/L range) inhibited acetylcholinesterase activity (up to 37%). Fluoxetine (at mg/L) also decreased the number of both feeding and active individuals (by 67%), decreased fish active time (up to 93%) and increased movement delay almost 3-fold (274%). Overall, acutely exposed P. microps were able to cope with fluoxetine toxicity at the μg/L range but higher concentrations (mg/L) affected fish cholinergic system and behavioural responses.