Chronic, low concentration exposure to pharmaceuticals impacts multiple organ systems in zebrafish

A multi-marker assessment of sewage contamination in streams using human-associated indicator bacteria, human-specific viruses, and pharmaceuticals

Human sewage contaminates waterways, delivering excess nutrients, pathogens, chemicals, and other toxic contaminants. Contaminants and various sewage indicators are measured to monitor and assess water quality, but these analytes vary in their representation of sewage contamination and the inferences about water quality they support. We measured the occurrence and concentration of multiple microbiological (n = 21) and chemical (n = 106) markers at two urban stream locations in Milwaukee, Wisconsin, USA over two years. Five-day composite water samples (n = 98) were collected biweekly, and sewage influent samples (n = 25) were collected monthly at a Milwaukee, WI water reclamation facility. We found the vast majority of markers were not sensitive enough to detect sewage contamination. To compare analytes for monitoring applications, five consistently detected human sewage indicators were used to evaluate temporal patterns of sewage contamination, including microbiological (pepper mild mottle virus, human Bacteroides, human Lachnospiraceae) and chemical (acetaminophen, metformin) markers. The proportion of human sewage in each stream was estimated using the mean influent concentration from the water reclamation facility and the mean concentration of all stream samples for each sewage indicator marker. Estimates of instream sewage pollution varied by marker, differing by up to two orders of magnitude, but four of the five sewage markers characterized Underwood Creek (mean proportions of human sewage ranged 0.0025 % - 0.075 %) as less polluted than Menomonee River (proportions ranged 0.013 % - 0.14 %) by an order of magnitude more. Chemical markers correlated with each other and yielded higher estimates of sewage pollution than microbial markers, which exhibited greater temporal variability. Transport, attenuation, and degradation processes can influence chemical and microbial markers differently and cause variation in human sewage estimates. Given the range of potential human and ecological health effects of human sewage contamination, robust characterization of sewage contamination that uses multiple lines of evidence supports monitoring and research applications.

An oral toxicity assessment of a mosquito larvicidal transgenic algae (Chlamydomonas reinhardtii) using adult Zebrafish and its embryos

Mosquito-borne diseases pose a global health threat, with pathogens like Malaria, Dengue fever, and others transmitted by mosquitoes. Our study focuses on evaluating the toxicity of genetically engineered mosquito larvicidal algae (Chlamydomonas reinhardtii) to non-target organisms, specifically Zebrafish. We conducted a 90-day experiment, feeding Zebrafish different combinations of larvicidal algae and commercial fish feed. Statistical analysis revealed no significant differences in mortality, allergenicity, or moribundity among groups. Hematology, molecular analysis, and necropsy showed no physiological differences. Our findings indicate that the transgenic algae (TN72.cry11Ba) had no adverse effects on adult Zebrafish or their larvae. This study confirmed the safety of algae on non-target organisms, such as zebrafish.

Carbamazepine transmits immune effect by activation of gut-liver axis and TLR signaling pathway from parental zebrafish to offspring

Carbamazepine (CBZ) has been identified in the aquatic environment as an emerging contaminant. Its immune effect across generations at environmentally relevant concentrations is little known. We aim to elucidate the effects of CBZ on the immune system in zebrafish (Danio rerio), hypothesizing the effects caused by CBZ exposure in the parental generation can be passed on to its offspring, leading to impairment of innate immune function and defense against pathogen weakened. A suite of bioassays (including a test with added lipopolysaccharide) was used to measure the effects of environmentally relevant levels of CBZ (1, 10, and 100 μg/l) on zebrafish at multiple biological levels, and across 2 successive generations (21 days exposure for F0; 5 and 21 days exposure or nonexposure for F1). The results showed that CBZ affected homeostasis in the immune system, caused liver vacuolization, increased the inflammation-related microbiota proportion in gut, and decreased reproduction, by induction of oxidative stress and modulation of Toll-like receptors (TLR) signaling pathway on gut-liver axis. The effects of exposure to CBZ over 21 days in F0 could be passed to the next generation. Intergenerational effects on TLR and antioxidant defense system were also observed in nonexposed F1 at 5 days post-fertilization (5 dpf), but diminished at 21 dpf. The finding provided evidence to unravel immune response by gut-liver axis mediated and oxidative stress under 4 test conditions. The study has raised a potential concern about the multigenerational immune effects of environmental pollutants and calls for a focus on the risk of synergetic pathogen infection.

Emerging Contaminants in the Effluent of Wastewater Should Be Regulated: Which and to What Extent?

Effluent discharged from urban wastewater treatment plants (WWTPs) is a major source of emerging contaminants (ECs) requiring effective regulation. To this end, we collected discharge datasets of pharmaceuticals (PHACs) and endocrine-disrupting chemicals (EDCs), representing two primary categories of ECs, from Chinese WWTP effluent from 2012 to 2022 to establish an exposure database. Moreover, high-risk ECs' long-term water quality criteria (LWQC) were derived using the species sensitivity distribution (SSD) method. A total of 140 ECs (124 PHACs and 16 EDCs) were identified, with concentrations ranging from N.D. (not detected) to 706 μg/L. Most data were concentrated in coastal regions and Gansu, with high ecological risk observed in Gansu, Hebei, Shandong, Guangdong, and Hong Kong. Using the assessment factor (AF) method, 18 high-risk ECs requiring regulation were identified. However, only three of them, namely carbamazepine, ibuprofen, and bisphenol-A, met the derivation requirements of the SSD method. The LWQC for these three ECs were determined as 96.4, 1010, and 288 ng/L, respectively. Exposure data for carbamazepine and bisphenol-A surpassed their derived LWQC, indicating a need for heightened attention to these contaminants. This study elucidates the occurrence and risks of ECs in Chinese WWTPs and provides theoretical and data foundations for EC management in urban sewage facilities.

The adsorption and its mechanism of venlafaxine by original and aged polypropylene microplastic and the changes of joint toxicity

Conjugation with the increment of consumption of polypropylene (PP) masks and antidepressants during pandemic, PP microplastics (MPs) and Venlafaxine (VEN) widely co-existed in surface waters. However, their environmental fate and the combined toxicity were unclear. Hence, we investigated the adsorption behaviors, and associated mechanisms of PP MPs for VEN. The impact factors including pH, salinity, and MPs aging were estimated. The results indicated PP MPs could adsorb amount of VEN within 24 h. The pseudo second-order kinetic model (R2 = 0.97) and Dubinin-Radushkevich model (R2 = 0.89) fitted well with the adsorption capacity of PP MPs for VEN, implying that chemical adsorption accompanied by electrostatic interaction might be the predominant mode for the interactions between PP MPs and VEN. Meanwhile, the adsorption capacity of PP MPs declined from pH of 2.5-4.5 and then increased from 4.5 to 9.5. The increased salinity (5-35 ppt) significantly suppressed the adsorption capacity. Aging by sunlight and UV triggered the formation of new functional group (carbonyl) on MPs, and then enhanced the adsorption capacity for VEN. Gaussian Model analysis further evidenced the electrostatic adsorption occurring in PP MPs and VEN. The combined exposure to PP MPs and VEN showed significantly antagonistic toxicity on Daphnia magna. The adsorption of VEN by PP MPs mitigated the lethal effects and behavioral function impairment posed by VEN on animals, implying the potential protective effects on zooplankton by PP MPs. This study for the first time provides perspective for assessing the environmental fate of MPs and antidepressants in aquatic system.

Emerging pollutants in etiology and pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a multifactorial endocrine disorder affecting reproductive-aged women worldwide. Although genetic and lifestyle factors have been implicated in its etiology, emerging evidence suggests that exposure to environmental pollutants may also contribute significantly to the development and pathophysiology of PCOS. This review article aims to provide a comprehensive overview of the potential role of emerging pollutants, including pharmaceuticals and personal care products (PPCPs), microplastics, endocrine disruptors, and nanoparticles, in PCOS development. The article summarizes the current understanding of PCOS pathogenesis and its clinical manifestations. Subsequently, it delves into the mechanisms of action of the emerging pollutants, exploring how they may disrupt the endocrine system, interfere with hormonal regulation, and contribute to the manifestation of PCOS symptoms. Moreover, the potential for cumulative effects and synergistic interactions between these pollutants demands a cautious approach when considering their role in PCOS etiology.

The occurrence of typical psychotropic drugs in the aquatic environments and their potential toxicity to aquatic organisms - A review

Psychotropic drugs (PDs) and their bioactive metabolites often persist in aquatic environments due to their typical physical properties, which made them resistant to removal by traditional wastewater treatment plants (WWTPs). Consequently, such drugs and/or their metabolites are frequently detected in both aquatic environments and organisms. Even at low concentrations, these drugs can exhibit toxic effects on non-target organisms including bony fish (zebrafish (Danio rerio) and fathead minnows) and bivalves (freshwater mussels and clams). This narrative review focuses on the quintessential representatives of three different categories of PDs-antiepileptics, antidepressants, and antipsychotics. The data regarding their concentrations occurring in the environment, patterns of distribution, the degree of enrichment in various tissues of aquatic organisms, and the toxicological effects on them are summarized. The toxicological assessments of these drugs included the evaluation of their effects on the reproductive, embryonic development, oxidative stress-related, neurobehavioral, and genetic functions in various experimental models. However, the mechanisms underlying the toxicity of PDs to aquatic organisms and their potential health risks to humans remain unclear. Most studies have focused on the effects caused by acute short-term exposure due to limitations in the experimental conditions, thus making it necessary to investigate the chronic toxic effects at concentrations that are in coherence with those occurring in the environment. Additionally, this review aims to raise awareness and stimulate further research efforts by highlighting the gaps in the understanding of the mechanisms behind PD-induced toxicity and potential health risks. Ultimately, the study underscores the importance of developing advanced remediation methods for the removal of PDs in WWTPs and encourages a broader discussion on mitigating their environmental impacts.

Pollutants in aquatic system: a frontier perspective of emerging threat and strategies to solve the crisis for safe drinking water

Water is an indispensable natural resource and is the most vital substance for the existence of life on earth. However, due to anthropogenic activities, it is being polluted at an alarming rate which has led to serious concern about water shortage across the world. Moreover, toxic contaminants released into water bodies from various industrial and domestic activities negatively affect aquatic and terrestrial organisms and cause serious diseases such as cancer, renal problems, gastroenteritis, diarrhea, and nausea in humans. Therefore, water treatments that can eliminate toxins are very crucial. Unfortunately, pollution treatment remains a difficulty when four broad considerations are taken into account: effectiveness, reusability, environmental friendliness, and affordability. In this situation, protecting water from contamination or creating affordable remedial techniques has become a serious issue. Although traditional wastewater treatment technologies have existed since antiquity, they are both expensive and inefficient. Nowadays, advanced sustainable technical approaches are being created to replace traditional wastewater treatment processes. The present study reviews the sources, toxicity, and possible remediation techniques of the water contaminants.

Remediation of fomesafen contaminated soil by Bacillus sp. Za: Degradation pathway, community structure and bioenhanced remediation

Fomesafen is a diphenyl ether herbicide used to control the growth of broadleaf weeds in bean fields. The persistence, phytotoxicity, and negative impact on crop rotation associated with this herbicide have led to an increasing concern about the buildup of fomesafen residues in agricultural soils. The exigent matter of treatment and remediation of soils contaminated with fomesafen has surfaced. Nevertheless, the degradation pathway of fomesafen in soil remains nebulous. In this study, Bacillus sp. Za was utilized to degrade fomesafen residues in black and yellow brown soils. Fomesafen's degradation rate by strain Za in black soil reached 74.4%, and in yellow brown soil was 69.2% within 30 days. Twelve intermediate metabolites of fomesafen were identified in different soils, with nine metabolites present in black soil and eight found in yellow brown soil. Subsequently, the degradation pathway of fomesafen within these two soils was inferred. The dynamic change process of soil bacterial community structure in the degradation of fomesafen by strain Za was analyzed. The results showed that strain Za potentially facilitate the restoration of bacterial community diversity and richness in soil samples treated with fomesafen, and there were significant differences in species composition at phylum and genus levels between these two soils. However, both soils shared a dominant phylum and genus, Actinobacteriota, Proteoobacteria, Firmicutes and Chloroflexi dominated in two soils, with a high relative abundance of Sphingomonas and Bacillus. Moreover, an intermediate metabolite acetaminophen degrading bacterium, designated as Pseudomonas sp. YXA-1, was isolated from yellow brown soil. When strain YXA-1 was employed in tandem with strain Za to remediate fomesafen contaminated soil, the degradation rate of fomesafen markedly increased. Overall, this study furnishes crucial insights into the degradation pathway of fomesafen in soil, and presents bacterial strain resources potentially beneficial for soil remediation in circumstances of fomesafen contamination.

Ability of Lactobacillus brevis 47f to Alleviate the Toxic Effects of Imidacloprid Low Concentration on the Histological Parameters and Cytokine Profile of Zebrafish (Danio rerio)

In the present article, the possible mitigation of the toxic effect of imidacloprid low-concentration chronic exposure on Danio rerio by the probiotic strain Lactobacillus brevis 47f (1 × 108 CFU/g) was examined. It was found that even sublethal concentration (2500 µg/L) could lead to the death of some fish during the 60-day chronic experiment. However, the use of Lactobacillus brevis 47f partially reduced the toxic effects, resulting in an increased survival rate and a significant reduction of morphohistological lesions in the intestines and kidneys of Danio rerio. The kidneys were found to be the most susceptible organ to toxic exposure, showing significant disturbances. Calculation of the histopathological index, measurement of morphometric parameters, and analysis of principal components revealed the most significant parameters affected by the combined action of imidacloprid and Lactobacillus brevis 47f. This effect of imidacloprid and the probiotic strain had a multidirectional influence on various pro/anti-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-8). Therefore, the results suggest the possibility of further studying the probiotic strain Lactobacillus brevis 47f as a strain that reduces the toxic effects of xenobiotics. Additionally, the study established the possibility of using imidacloprid as a model toxicant to assess the detoxification ability of probiotics on the kidney and gastrointestinal tract of fish.

Chemical prioritization of pharmaceuticals and personal care products in an urban tributary of the Potomac River

Pharmaceuticals and personal care products (PPCPs) are incredibly diverse in terms of chemical structures, physicochemical properties, and modes of action, making their environmental impacts challenging to assess. New chemical prioritization methodologies have emerged that compare contaminant monitoring concentrations to multiple toxicity data sources, including whole organism and high-throughput data, to develop a list of "high priority" chemicals requiring further study. We applied such an approach to assess PPCPs in Hunting Creek, an urban tributary of the Potomac River near Washington, DC, which has experienced extensive human population growth. We estimated potential risks of 99 PPCPs from surface water and sediment collected upstream and downstream of a major wastewater treatment plant (WWTP), nearby combined sewer overflows (CSO), and in the adjacent Potomac River. The greatest potential risks to the aquatic ecosystem occurred near WWTP and CSO outfalls, but risk levels rapidly dropped below thresholds of concern - established by previous chemical prioritization studies - in the Potomac mainstem. These results suggest that urban tributaries, rather than larger rivers, are important to monitor because their lower or intermittent flow may not adequately dilute contaminants of concern. Common psychotropics, such as fluoxetine and venlafaxine, presented the highest potential risks, with toxicity quotients often > 10 in surface water and > 1000 in sediment, indicating the need for further field studies. Several ubiquitous chemicals such as caffeine and carbamazepine also exceeded thresholds of concern throughout our study area and point to specific neurotoxic and endocrine modes of action that warrant further investigation. Since many "high priority" chemicals in our analysis have also triggered concerns in other areas around the world, better coordination is needed among environmental monitoring programs to improve global chemical prioritization efforts.

The Effect of Carbamazepine on Performance, Carcass Value, Hematological and Biochemical Blood Parameters, and Detection of Carbamazepine and Its Metabolites in Tissues, Internal Organs, and Body Fluids in Growing Rabbits

Antiepileptic drugs (e.g., carbamazepine; CBZ) are widely prescribed for various conditions beyond epilepsy, including neurologic and psychiatric disorders. These medications can have both favorable and unfavorable impacts on mood, anxiety, depression, and psychosis. CBZ has been found at low concentrations (in the unit of nanograms per liter) in rivers, surface water, and even drinking water. As a result, when reclaimed wastewater is used for irrigation in agricultural ecosystems, CBZ can be reintroduced into the environment. That is why we tested different doses of CBZ in rabbits' feed as the meat is consumed in every community, has no religious barriers, and the potential risk of consuming meat which has been exposed to CBZ treatment is not known. Also, the evidence of the effect of CBZ on rabbits is missing. Mainly, the CBZ doses affected the count of leukocytes and other blood traits, meaning the higher the dose, the higher the reduction. Moreover, there were only low amounts of CBZ in rabbits' meat or tissues when they were exposed to the treatment.

Evaluating pharmaceuticals and other organic contaminants in the Lac du Flambeau Chain of Lakes using risk-based screening techniques

In an investigation of pharmaceutical contamination in the Lac du Flambeau Chain of Lakes (hereafter referred to as "the Chain"), few contaminants were detected; only eight pharmaceuticals and one pesticide were identified among the 110 pharmaceuticals and other organic contaminants monitored in surface water samples. This study, conducted in cooperation with the Lac du Flambeau Tribe's Water Resource Program, investigated these organic contaminants and potential biological effects in channels connecting lakes throughout the Chain, including the Moss Lake Outlet site, adjacent to the wastewater treatment plant lagoon. Of the 6 sites monitored and 24 samples analyzed, sample concentrations and contaminant detection frequencies were greatest at the Moss Lake Outlet site; however, the concentrations and detection frequencies of this study were comparable to other pharmaceutical investigations in basins with similar characteristics. Because established water-quality benchmarks do not exist for the pharmaceuticals detected in this study, alternative screening-level water-quality benchmarks, developed using two U.S. Environmental Protection Agency toxicological resources (ToxCast database and ECOTOX knowledgebase), were used to estimate potential biological effects associated with the observed contaminant concentrations. Two contaminants (caffeine and thiabendazole) exceeded the prioritization threshold according to ToxCast alternative benchmarks, and four contaminants (acetaminophen, atrazine, caffeine, and carbamazepine) exceeded the prioritization threshold according to ECOTOX alternative benchmarks. Atrazine, an herbicide, was the most frequently detected contaminant (79% of samples), and it exhibited the strongest potential for biological effects due to its high estimated potency. Insufficient toxicological information within ToxCast and ECOTOX for gabapentin and methocarbamol (which had the two greatest concentrations in this study) precluded alternative benchmark development. This data gap presents unknown potential environmental impacts. Future research examining the biological effects elicited by these two contaminants as well as the others detected in this study would further elucidate the ecological relevance of the water chemistry results generated though this investigation.

Hazard and health risk assessment of exposure to pharmaceutical active compounds via toxicological evaluation by zebrafish

The uncontrolled or continuous release of effluents from wastewater treatment plants leads to the omnipresence of pharmaceutical active compounds (PhACs) in the aquatic media. Today, this is a confirmed problem becoming a main subject of twin public and scientific concerns. However, still little information is available about the long-term impacts of these PhACs on aquatic organisms. In this review, efforts were made to reveal correlation between the occurrence in the environment, ecotoxicological and health risks of different PhACs via toxicological evaluation by zebrafish (Danio rerio). This animal model served as a bioindicator for any health impacts after the exposure to these contaminants and to better understand the responses in relation to human diseases. This review paper focused on the calculation of Risk Quotients (RQs) of 34 PhACs based on environmental and ecotoxicological data available in the literature and prediction from the ECOSAR V2.2 software. To the best of the authors' knowledge, this is the first report on the risk assessment of PhACs by the two different methods as mentioned above. RQs showed greater difference in potential environmental risks of the PhACs. These differences in risk values underline the importance of environmental and experimental factors in exposure conditions and the interpretation of RQ values. While the results showed high risk to Danio rerio of the majority of PhACs, risk qualification of the others varied between moderate to insignifiant. Further research is needed to assess pharmaceutical hazards when present in wastewater before discharge and monitor the effectiveness of treatment processes. The recent new advances in the morphological assessment of toxicant-exposed zebrafish larvae for the determination of test compounds effects on the developmental endpoints were also discussed. This review emphasizes the need for strict regulations on the release of PhACs into environmental media in order to minimize their toxicity to aquatic organisms.

Individual and combined effects of amoxicillin and carbamazepine to the marine copepod Tigriopus fulvus

Pharmaceuticals can be considered a global threat to aquatic ecosystems due to their pseudo-persistence and their potential toxicity towards non-target species. Amoxicillin (AMX) and carbamazepine (CBZ) and their mixture (1:1) were investigated on the marine copepod Tigriopus fulvus (Fischer, 1860) considering both acute and chronic endpoints. While acute and chronic exposure did not directly affect survival, reproductive endpoints were affected like the mean egg hatching time that was significantly longer than the negative control for treatments with AMX (0.789 ± 0.079 μg/L), CBZ (8.88 ± 0.89 μg/L), and AMX and CMZ as a mixture (1.03 ± 0.10 μg/L and 0.941 ± 0.094 μg/L), in that order.

Bioaccumulation as a method of removing psychoactive compounds from wastewater using aquatic plants

Since WWTPs are not able to eliminate all psychoactive pharmaceuticals, these compounds become a part of the aquatic ecosystem. Our results indicate that compounds such as codeine or citalopram are eliminated with low efficiency (<38%), and compounds such as venlafaxine, oxazepam, or tramadol even with almost no efficiency. Lower elimination efficiency may be caused by the accumulation of these compounds in the wastewater treatment process. This study is focused on the possibility to remove problematic psychoactive compounds using aquatic plants. HPLC-MS analysis of the leaf extract obtained from studied plants showed that the amount of accumulated methamphetamine was highest in Pistia stratiotes and lower in the leaves of Limnophila sessiliflora and Cabomba caroliniana. However, tramadol and venlafaxine were accumulated considerably only in Cabomba caroliniana. Our study demonstrates that especially these three compounds - tramadol, venlafaxine, and methamphetamine, are accumulated in aquatic plants and can be removed from the aquatic environment. In our study was also observed that helophytic aquatic plants show a higher ability to remove psychoactive compounds from wastewater. Iris pseudacorus showed the best results in selected pharmaceuticals removal with no bioaccumulation effect in leaves or roots.

Carbamazepine, venlafaxine, tramadol, and their main metabolites: Toxicological effects on zebrafish embryos and larvae

Pharmaceutical compounds and their metabolites are found in natural and wastewater. However, investigation of their toxic effects on aquatic animals has been neglected, especially for metabolites. This work investigated the effects of the main metabolites of carbamazepine, venlafaxine and tramadol. Zebrafish embryos were exposed (0.1-100 µg/L) for 168hpf exposures to each metabolite (carbamazepine-10,11-epoxide, 10,11-dihydrocarbamazepine, O-desmethylvenlafaxine, N-desmethylvenlafaxine, O-desmethyltramadol, N-desmethyltramadol) or the parental compound. A concentration-response relationship was found for the effects of some embryonic malformations. Carbamazepine-10,11-epoxide, O-desmethylvenlafaxine and tramadol elicited the highest malformation rates. All compounds significantly decreased larvae responses on a sensorimotor assay compared to controls. Altered expression was found for most of the 32 tested genes. In particular, abcc1, abcc2, abcg2a, nrf2, pparg and raraa were found to be affected by all three drug groups. For each group, the modelled expression patterns showed differences in expression between parental compounds and metabolites. Potential biomarkers of exposure were identified for the venlafaxine and carbamazepine groups. These results are worrying, indicating that such contamination in aquatic systems may put natural populations at significant risk. Furthermore, metabolites represent a real risk that needs more scrutinising by the scientific community.

Interactive effects of venlafaxine and thermal stress on zebrafish (Danio rerio) inflammatory and heat shock responses

Venlafaxine (VFX), a commonly prescribed antidepressant often detected in wastewater effluent, and acute temperature elevations from climate change and increased urbanization, are two environmental stressors currently placing freshwater ecosystems at risk. This study focused on understanding if exposure to VFX impacts the agitation temperature (T_ag) and critical thermal maximum (CT_max) of zebrafish (Danio rerio). Additionally, we examined the interactive effects of VFX and acute thermal stress on zebrafish heat shock and inflammatory immune responses. A 96 h 1.0 μg/L VFX exposure experiment was conducted, followed by assessment of thermal tolerance via CT_max challenge. Heat shock proteins and pro-inflammatory immune cytokines were quantified through gene expression analysis by quantitative PCR (qPCR) on hsp 70, hsp 90, hsp 47, il-8, tnfα, and il-1β within gill and liver tissue. No significant changes in agitation temperature between control and exposed fish were observed, nor were there any differences in CT_max based on treatment. Unsurprisingly, hsp 47, 70, and 90 were all upregulated in groups exposed solely to CT_max, while only hsp 47 within gill tissue showed signs of interactive effects, which was significantly decreased in fish exposed to both VFX and CT_max. No induction of an inflammatory response occurred. This study demonstrated that environmentally relevant concentrations of VFX have no impact on thermal tolerance performance in zebrafish. However, VFX can cause diminished function of protective heat shock mechanisms, which could be detrimental to freshwater fish populations and aquatic ecosystems as temperature spikes become more frequent from climate change and urbanization near watersheds.

Linking chemical exposure and fish metabolome: Discovering new biomarkers of environmental exposure of Argyrosomus regius to the antidepressant venlafaxine

In this study, a non-target metabolomic approach was used to investigate changes in the metabolome of juvenile meagre (Argyrosomus regius) exposed to venlafaxine (20 µg/L). A total of 24, 22 and 8 endogenous metabolites tentatively identified in liver, brain and plasma, respectively, were significantly changed in venlafaxine exposed meagre, showing tissue-dependent variations in the metabolic profile. The amino acids tryptophan, tyrosine and phenylalanine, which are related to the synthesis, availability, and expression of neurotransmitters (e.g., serotonin, dopamine, epinephrine), showed to be dysregulated by venlafaxine exposure. A high impact was observed in fish brain metabolome that showed a trend of up-regulation for most of the tentatively identified metabolites. In conclusion, the identification of possible biomarkers of exposure in fish metabolome to environmental stressors such as venlafaxine is crucial to assess early signal changes at molecular level, enabling the prevention of deleterious effects at the organism and population levels.

Elucidating the Effects of the Lipids Regulators Fibrates and Statins on the Health Status of Finfish Species: A Review

The most documented fibrates are gemfibrozil, clofibrate and bezafibrate, while for statins, the majority of the published literature focuses on atorvastatin and simvastatin. The present work reviews previously published research concerning the effects of these hypocholesterolaemic pharmaceuticals on fish, with a particular focus on commercially important species, commonly produced by the European aquaculture industry, specifically in recirculated aquaculture systems (RAS). Overall, results suggest that both acute and chronic exposures to lipid-lowering compounds may have adverse effects on fish, disrupting their capacity to excrete exogenous substances, as well as both lipid metabolism and homeostasis, causing severe ontogenetic and endocrinological abnormalities, leading to hampered reproductive success (e.g., gametogenesis, fecundity), and skeletal or muscular malformations, having serious repercussions on fish health and welfare. Nonetheless, the available literature focusing on the effects of statins or fibrates on commonly farmed fish is still limited, and further research is required to understand the implications of this matter on aquaculture production, global food security and, ultimately, human health.

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.

Effects of carbamazepine on gut microbiota, ARGs and intestinal health in zebrafish

Carbamazepine (CBZ) in the aquatic environment is recognized as a potential threat to aquatic organisms and public health. However, the response of organism intestinal health, resistome, microbiota, and their relationship after CBZ exposure has been rarely reported. This study aimed to explore the impacts of CBZ on gut microbiota, antibiotic resistance genes (ARGs) and the expression of intestinal health related genes as well as their interaction using the zebrafish model. 16 S ribosomal RNA sequencing indicated CBZ altered the composition of gut microbiota. Using high-throughput quantitative polymerase chain reaction (HT-qPCR), we found the number and abundance of ARGs were impacted by CBZ levels and exposure duration. We also observed the upregulated expression of the pro-inflammatory gene IL6 and downregulated expression of toll-like receptor gene TLR2 and intestinal barrier gene TJP2a at different exposure times. Correlation analyses revealed that Geobacillus, Rhodococcus, Ralstonia, Delftia, Luteolibacter and Escherichia-Shigella might be the main bacterial genera carrying ARGs. Meanwhile, Cetobacterium and Aeromonas could be the dominant bacteria affecting intestinal health related genes. Our results could contribute to understanding the health risks of CBZ to the intestinal microecology of aquatic animals.

Exposure to acetaminophen impairs gametogenesis and fertility in zebrafish (Danio rerio)

Acetaminophen (ACE; paracetamol) is one of the most widely used nonsteroidal anti-inflammatory drugs worldwide and is often found in aquatic systems, where it can act on nontarget species and impair fish reproduction. This study aimed to investigate the effects of chronic exposure to environmentally relevant ACE concentrations (0.5, 5 and 50 µg/L) on multiple reproductive parameters in zebrafish (Danio rerio). Gametogenesis was analyzed using histology, morphometry, cell proliferation, and apoptosis. This study also evaluated sex steroids, and prostaglandin E₂ (PGE₂) levels, gene expression for sex steroids and PGE₂ receptors, fertilization rate, and semen quality. In females, exposure to 5 and 50 µg/L ACE induced larger and more abundant vitellogenic follicles and increased follicular atresia. In these treatments, males showed a lower proportion and proliferation of undifferentiated spermatogonia and a higher proportion of TUNEL-positive differentiated spermatogonia, spermatids, and spermatozoa, resulting in lower sperm production. ACE increased 17β-estradiol (E₂) and reduced 11-ketotestosterone levels in the testis, whereas only E₂ increased in the ovaries. In both sexes, gonadal PGE₂ levels were reduced. ACE at 50 µg/L induced an increase in the gene expression of androgen, estrogen, and PGE₂ receptors in the ovaries, and reduced expression in the testes. Results also showed lower egg production and fertilization rate from 28 days of exposure with reduced sperm quality. These results demonstrated that ACE impairs the reproductive performance of zebrafish, affecting multiple reproductive parameters, which may be caused by the synergistic action of the imbalance of sex steroids, with a reduction of PGE₂ and its receptors.

Judging Pharmaceutical Environmental Risk by its Cover? The Effects of Prescription Medication and Disease Severity on Environmental Risk Perception

Recent wastewater analyses performed in care homes for the elderly showed high levels of water pollution resulting from pharmaceutical waste. The way people perceive the environmental risk of pharmaceuticals can contribute to reversing this problem, but the factors that influence risk perception remain relatively unknown. The aims of the study are two-fold. We first focused on exploring the levels of knowledge regarding environment/water pollution due to pharmaceutical residues from the groups responsible for prescribing (health professionals), handling (staff), and consuming pharmaceuticals (residents) in care homes for the elderly. Second, we assessed the environmental risk perception of pharmaceuticals based on two main factors: prescription medication (nonprescribed versus prescribed) and disease severity (milder versus severe disease), accounting for their level of knowledge (deficit versus sufficiency of knowledge). The study was designed based on correlational research. Data were collected in homes for the elderly located in three Southwestern European countries (N = 300), using self-report surveys. Current knowledge was perceived to be low and the need to know more was perceived to be high, across all groups. As hypothesized, results indicated that to assess the environmental risk, participants made use of information that was unrelated to pharmaceutical persistence, bioaccumulation, and toxicity (PBT). Prescribed pharmaceuticals and/or medication used to treat severe diseases were perceived as being more hazardous for the environment. Simple main effects analysis comparing between knowledge levels confirmed that this effect occurred mostly when participants had knowledge deficit for disease severity but not for prescription medication. These misconceptions might discourage taking an active role in reducing the impact of pharmaceutical residues in the environment.

Prioritizing Pharmaceutical Contaminants in Great Lakes Tributaries Using Risk-Based Screening Techniques

In a study of 44 diverse sampling sites across 16 Great Lakes tributaries, 110 pharmaceuticals were detected of 257 monitored. The present study evaluated the ecological relevance of detected chemicals and identified heavily impacted areas to help inform resource managers and guide future investigations. Ten pharmaceuticals (caffeine, nicotine, albuterol, sulfamethoxazole, venlafaxine, acetaminophen, carbamazepine, gemfibrozil, metoprolol, and thiabendazole) were distinguished as having the greatest potential for biological effects based on comparison to screening-level benchmarks derived using information from two biological effects databases, the ECOTOX Knowledgebase and the ToxCast database. Available evidence did not suggest substantial concern for 75% of the monitored pharmaceuticals, including 147 undetected pharmaceuticals and 49 pharmaceuticals with screening-level alternative benchmarks. However, because of a lack of biological effects information, screening values were not available for 51 detected pharmaceuticals. Samples containing the greatest pharmaceutical concentrations and having the highest detection frequencies were from Lake Erie, southern Lake Michigan, and Lake Huron tributaries. Samples collected during low-flow periods had higher pharmaceutical concentrations than those collected during increased-flow periods. The wastewater-treatment plant effluent content in streams correlated positively with pharmaceutical concentrations. However, deviation from this correlation demonstrated that secondary factors, such as multiple pharmaceutical sources, were likely present at some sites. Further research could investigate high-priority pharmaceuticals as well as those for which alternative benchmarks could not be developed. Environ Toxicol Chem 2022;41:2221-2239. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A critical review on paracetamol removal from different aqueous matrices by Fenton and Fenton-based processes, and their combined methods

Paracetamol (PCT), also known as acetaminophen, is a drug used to treat fever and mild to moderate pain. After consumption by animals and humans, it is excreted through the urine to the sewer systems, wastewater treatment plants, and other aquatic/natural environments. It has been detected in trace amounts in effluents of wastewater plant treatments, sewage sludge, hospital wastewaters, surface waters, and drinking water. PCT can cause genetic code damage, oxidative degradation of lipids, and denaturation of protein in cells, and its toxicity has been well-proven in bacteria, algae, macrophytes, protozoan, and fishes. To avoid its harmful health problems over living beings, powerful Fenton and Fenton-based treatments as pre-eminent advanced oxidation processes (AOPs) have been developed because of the inefficient treatment by conventional treatments. This paper presents a comprehensive and critical review over the application of such Fenton technologies to remove PCT from natural waters, synthetic wastewaters, and real wastewaters. The characteristics and main results obtained using Fenton, photo-Fenton, electro-Fenton, and photoelectro-Fenton are described, making special emphasis in the oxidative action of the generated reactive oxygen species. Hybrid processes based on the coupling with ultrasounds, gamma radiation, photocatalysis, photoelectrocatalysis, zero-valent iron-activated persulfate, adsorption, and microbial fuel cells, are analyzed. Sequential treatments involving the initiation with plasma gliding arc discharge and post-biological process are detailed. Comparative results with other available AOPs are also described and discussed. Finally, 13 aromatic by-products and 9 short-linear aliphatic carboxylic acid detected during the PCT removal by Fenton and Fenton-based processes are reported, with the proposal of three parallel pathways for its initial degradation.

Low doses and lifecycle exposure of waterborne antidepressants in zebrafish model: A survey on sperm traits, reproductive behaviours, and transcriptome responses

Venlafaxine and citalopram have been commonly found in surface water and may disrupt fish reproduction, yet the long-term impact and the underlying mechanism are largely unknown. Here, zebrafish were exposed to 0.1-100 μg/L venlafaxine and citalopram for their entire life cycle from embryo to adult, respectively. After exposure for 180 days, the lowest observable effective concentration (LOEC) of venlafaxine and citalopram to significantly reduce the mean number of egg production in adults were 10 and 1 μg/L, respectively, whereas the fertilization rate displayed no significant changes. Further, we investigated the impacts of venlafaxine and citalopram in a reproductive context, including sperm quality and reproductive behaviour. In contrast, venlafaxine and citalopram exposure did not affect sperm quality but caused a reduction of reproductive behaviour (e.g., mating duration and mating interval) of adults exposed to 1-10 μg/L of the antidepressant. Transcriptomic profiling of the whole ovary revealed that lifecycle venlafaxine and citalopram exposure significantly affected the Na⁺/Cl^- dependent neurotransmitter transporters signaling. Moreover, immune system-mediated ovarian regeneration and creatine metabolism regulated energy metabolism were proposed as the novel mechanism in the observed effects. Taken together, our results highlight the risk of lifecycle venlafaxine and citalopram exposure to fish reproduction and provide novel perspectives for unveiling the mechanism of female reproductive dysfunction.

Enantioselective Ecotoxicity of Venlafaxine in Aquatic Organisms: Daphnia and Zebrafish

Venlafaxine is a chiral antidepressant detected in aquatic compartments. It was recently included in the 3rd Watch List from the European Union. The present study aimed to investigate venlafaxine toxicity effects, targeting possible enantioselective effects, using two aquatic organisms, daphnia (Daphnia magna) and zebrafish (Danio rerio). Specimens were exposed to both racemate, (R,S)-venlafaxine (VEN), and to pure enantiomers. Acute assays with daphnia showed that up to 50 000 μg/L of the (R,S)-VEN induced no toxicity. Organisms were also exposed to sublethal concentrations (25-400 μg/L) of (R,S)-, (R)- and (S)-VEN, for 21 days. No significant effects on mortality, age at first reproduction, and size of the first clutch were observed. However, a decrease in fecundity was observed for both enantiomers at the highest concentration. Regarding zebrafish, the effects of venlafaxine on mortality, embryo development, behavior, biochemistry, and melanin pigmentation were investigated after 96 h of exposure to the range of 0.3-3000 μg/L. (R)-VEN significantly increased the percentage of malformations in comparison with (S)-VEN. Behavior was also enantiomer dependent, with a decrease in the total distance moved and an increase in avoidance behavior observed in organisms exposed to (R)-VEN. Despite the biochemical variations, no changes in redox homeostasis were observed. (R)-VEN also led to an increase in zebrafish pigmentation. The different susceptibility to venlafaxine and enantioselective effects were observed in zebrafish. Our results suggest that at environmental levels (R,S)-VEN and pure enantiomers are not expected to induce harmful effects in both organisms, but (R)-VEN increased malformations in zebrafish larvae, even at reported environmental levels. These results highlight the importance of including enantioselective studies for an accurate risk assessment of chiral pollutants. Environ Toxicol Chem 2022;41:1851-1864. © 2022 SETAC.

Occurrence of pharmaceuticals and cocaine in the urban drainage channels located on the outskirts of the São Vicente Island (São Paulo, Brazil) and related ecological risk assessment

"Wealth by the sea and poverty away from the sea breeze" is a metaphor that mirrors what happens along the Brazilian coastal zone, namely in São Vicente Island, São Paulo, Brazil. Due to the high cost of the properties on this shore, the impoverished population started to migrate to the northern outskirts of the island (away from the tourist beaches), potentiating the emergence of poor housing conditions, namely stilt-house slums. Consequently, the urban drainage channels across these outskirts neighbourhoods are potentially contaminated by human wastes. In this context, the occurrence and preliminary ecological risk assessment of eleven pharmaceuticals of various therapeutic classes (including cocaine and its primary metabolite, benzoylecgonine) were investigated, for the first time, in five urban drainage channels whose diffuse loads flow continuously to the estuarine waters of São Vicente Island. The results showed the widespread presence of these environmental stressors in all urban channels analysed, namely losartan (7.3-2680.0 ng/L), caffeine (314.0-726.0 ng/L), acetaminophen (7.0-78.2 ng/L), atenolol (6.2-23.6 ng/L), benzoylecgonine (10.2-17.2 ng/L), furosemide (1.0-7.2 ng/L), cocaine (2.3-6.7 ng/L), carbamazepine (0.2-2.6 ng/L), diclofenac (1.1-2.5 ng/L), orphenadrine (0.2-1.1 ng/L) and chlortalidone (0.5-1.0 ng/L). The overall total estimated load of pharmaceuticals and personal care products flowing to the estuarine waters of São Vicente Island is on the order of 41.1 g/day. The ecological risk assessment revealed a great environmental concern for São Vicente Island, ranging between low (e.g. carbamazepine and cocaine) and moderate to high (e.g. caffeine, acetaminophen and losartan) threats for the aquatic biota. Therefore, initiatives promoting basic sanitation, land-use regularisation and population awareness are highly recommended.

Acetaminophen Disrupts the Development of Pharyngeal Arch-Derived Cartilage and Muscle in Zebrafish

Acetaminophen is a common analgesic, but its potential effects on early embryonic development are not well understood. Previous studies using zebrafish (Danio rerio) have described the effects of acetaminophen on liver development and physiology, and a few have described gross physiological and morphological defects. Using a high but non-embryonic lethal dose of acetaminophen, we probed for defects in zebrafish craniofacial cartilage development. Strikingly, acetaminophen treatment caused severe craniofacial cartilage defects, primarily affecting both the presence and morphology of pharyngeal arch-derived cartilages of the viscerocranium. Delaying acetaminophen treatment restored developing cartilages in an order correlated with their corresponding pharyngeal arches, suggesting that acetaminophen may target pharyngeal arch development. Craniofacial cartilages are derived from cranial neural crest cells; however, many neural crest cells were still seen along their expected migration paths, and most remaining cartilage precursors expressed the neural crest markers sox9a and sox10, then eventually col2a1 (type II collagen). Therefore, the defects are not primarily due to an early breakdown of neural crest or cartilage differentiation. Instead, apoptosis is increased around the developing pharyngeal arches prior to chondrogenesis, further suggesting that acetaminophen may target pharyngeal arch development. Many craniofacial muscles, which develop in close proximity to the affected cartilages, were also absent in treated larvae. Taken together, these results suggest that high amounts of acetaminophen can disrupt multiple aspects of craniofacial development in zebrafish.

Risk-based screening for prioritisation of organic micropollutants in Swedish freshwater

Concerns about environmental contamination by organic micropollutants (OMPs) are increasing, due to their potential bioaccumulative and toxic properties. This study evaluated the risk posed by OMPs to aquatic ecosystems in Swedish freshwaters. The assessment was based on measured environmental concentrations (MEC) of OMPs in surface waters upstream and downstream of Swedish wastewater treatment plants (WWTPs). A novel optimised risk quotient (RQ_f) was used to identify potential high-risk substances in the aquatic environment. A secondary objective was to assess the impact of WWTP effluent on aquatic ecosystems using a novel impact factor (I) based on the risk quotient (RQ). Among the 126 substances investigated, four compounds (metformin, N,N-dimethyltetradecylamine, oxazepam, and venlafaxine) were identified as likely to pose a risk to aquatic ecosystems in Swedish surface waters (RQ_f>1), and five compounds (clindamycin, gemfibrozil, sertraline, o-desmethylvenlafaxine, and diclofenac) were identified as posing a moderate risk to aquatic ecosystems ( 0.1 <RQ_f<1). WWTP effluent appeared to pose an environmental risk for all recipient sites, but the impact of calculated RQ was site-specific. These results can be used by authorities to prioritise OMPs and contaminated hotspots, in order to decrease negative impacts on aquatic ecosystems. SYNOPSIS: A novel optimised risk assessment approach for identification of high-concern organic micropollutants in aquatic environments.

Rethinking the relevance of microplastics as vector for anthropogenic contaminants: Adsorption of toxicants to microplastics during exposure in a highly polluted stream - Analytical quantification and assessment of toxic effects in zebrafish (Danio rerio)

Given the increasing amounts of plastic debris entering marine and freshwater ecosystems, there is a growing demand for environmentally relevant exposure scenarios to improve the risk assessment of microplastic particles (MPs) in aquatic environments. So far, data on adverse effects in aquatic organisms induced by naturally exposed MPs are scarce and controversially discussed. As a consequence, we investigated the potential role of MPs regarding the sorption and transfer of environmental contaminants under natural conditions. For this end, a mixture of four common polymer types (polyethylene, polypropylene, polystyrene, polyvinyl chloride) was exposed to natural surface water in a polluted stream for three weeks. Samples of water, MP mixture, sediment, and suspended matter were target-screened for the presence of pollutants using GC/LC-MS, resulting in up to 94 different compounds. Possible adverse effects were investigated using several biomarkers in early developmental stages of zebrafish (Danio rerio). Exposure to natural stream water samples significantly inhibited acetylcholinesterase activity, altered CYP450 induction and modified behavioral patterns of zebrafish. In contrast, effects by samples of both non-exposed MPs and exposed MPs in zebrafish were less prominent than effects by water samples. In fact, the analytical target screening documented only few compounds sorbed to natural particles and MPs. Regarding acute toxic effects, no clear differentiation between different MPs and natural particles could be made, suggesting that - upon exposure in natural water bodies - MPs seem to approximate the sorption behavior of natural particles, presumably to a large extent due to biofilm formation. Thus, if compared to natural inorganic particles, MPs most likely do not transfer elevated amounts of environmental pollutants to biota and, therefore, do not pose a specific additional threat to aquatic organisms.

Abundance, fate, and effects of pharmaceuticals and personal care products in aquatic environments

Pharmaceuticals and personal care products (PPCPs) are found in wastewater, and thus, the environment. In this study, current knowledge about the occurrence and fate of PPCPs in aquatic systems-including wastewater treatment plants (WWTPs) and natural waters around the world-is critically reviewed to inform the state of the science and highlight existing knowledge gaps. Excretion by humans is the primary route of PPCPs entry into municipal wastewater systems, but significant contributions also occur through emissions from hospitals, PPCPs manufacturers, and agriculture. Abundance of PPCPs in raw wastewater is influenced by several factors, including the population density and demography served by WWTPs, presence of hospitals and drugs manufacturers in the sewershed, disease burden of the population served, local regulations, and climatic conditions. Based on the data obtained from WWTPs, analgesics, antibiotics, and stimulants (e.g., caffeine) are the most abundant PPCPs in raw wastewater. In conventional WWTPs, most removal of PPCPs occurs during secondary treatment, and overall removal exceeds 90% for treatable PPCPs. Regardless, the total PPCP mass discharged with effluent by an average WWTP into receiving waters (7.35-20,160 g/day) is still considerable, because potential adverse effects of some PPCPs (such as ibuprofen) on aquatic organisms occur within measured concentrations found in surface waters.

Comparison of toxic effects of atorvastatin and gemfibrozil on Daphnia magna

Atorvastatin (ATV) and gemfibrozil (GEM) are two typical lipid-lowering pharmaceuticals with different action modes, which are frequently detected in various water bodies owning to their wide usage. However, there is limited information about their effects on Daphnia magna. The present study addressed and compared the toxic effects of ATV and GEM on D. magna through determining the responses of the stress related genes (including Nrf2, Keap1, HO-1, GCLC, p53 and PIG3) in D. magna for 24 h and 48 h acute exposure and the changes of life history traits and swimming behaviors in a 21 days chronic exposure under different concentrations of ATV and GEM exposure (5 μg L^-1, 50 μg L^-1, 500 μg L^-1 and 5000 μg L^-1). Results showed that the expression of Nrf2, Keap1, HO-1, GCLC, p53 and PIG3 were induced to various degrees under the ATV exposure. There were similar performances for GEM. ATV and GEM caused the delay of first brooding and hatching time and decrease of eggs production number, especially in GEM exposure, reproduction of Daphnia was significantly inhibited, decreasing 38.51% compared to the control. ATV and GEM increased the heart rate of D. magna, and changed swimming behaviors of D. magna. In summary, two lipid-lowering pharmaceuticals caused oxidative stress on D. magna, subsequently brought about alterations in physiological traits. Comparatively, ATV pose more higher risks to D. magna than GEM, but the detailed action mechanisms of ATV and GEM on D. magna needs more investigations in future.

Demonstration of an aggregated biomarker response approach to assess the impact of point and diffuse contaminant sources in feral fish in a small river case study

The assessment of the exposure of aquatic wildlife to complex environmental mixtures of chemicals originating from both point and diffuse sources and evaluating the potential impact thereof constitutes a significant step towards mitigating toxic pressure and the improvement of ecological status. In the current proof-of-concept study, we demonstrate the potential of a novel Aggregated Biomarker Response (ABR) approach involving a comprehensive set of biomarkers to identify complex exposure and impacts on wild brown trout (Salmo trutta fario). Our scenario used a small lowland river in Germany (Holtemme river in the Elbe river catchment) impacted by two wastewater treatment plants (WWTP) and diffuse agricultural runoff as a case study. The trout were collected along a pollution gradient (characterised in a parallel study) in the river. Compared to fish from the reference site upstream of the first WWTP, the trout collected downstream of the WWTPs showed a significant increase in micronucleus formation, phase I and II enzyme activities, and oxidative stress parameters in agreement with increasing exposure to various chemicals. By integrating single biomarker responses into an aggregated biomarker response, the two WWTPs' contribution to the observed toxicity could be clearly differentiated. The ABR results were supported by chemical analyses and whole transcriptome data, which revealed alterations of steroid biosynthesis and associated pathways, including an anti-androgenic effect, as some of the key drivers of the observed toxicity. Overall, this combined approach of in situ biomarker responses complemented with molecular pathway analysis allowed for a comprehensive ecotoxicological assessment of fish along the river. This study provides evidence for specific hazard potentials caused by mixtures of agricultural and WWTP derived chemicals at sublethal concentrations. Using aggregated biomarker responses combined with chemical analyses enabled an evidence-based ranking of sites with different degrees of pollution according to toxic stress and observed effects.

Antidepressants as Endocrine Disrupting Compounds in Fish

As antidepressant usage by the global population continues to increase, their persistent detection in aquatic habitats from municipal wastewater effluent release has led to concerns of possible impacts on non-target organisms, including fish. These pharmaceuticals have been marketed as mood-altering drugs, specifically targeting the monoaminergic signaling in the brain of humans. However, the monoaminergic systems are highly conserved and involved in the modulation of a multitude of endocrine functions in vertebrates. While most studies exploring possible impact of antidepressants on fish have focused on behavioural perturbations, a smaller spotlight has been placed on the endocrine functions, especially related to reproduction, growth, and the stress response. The purpose of this review is to highlight the possible role of antidepressants as endocrine disruptors in fish. While studies linking the effects of environmentally relevant levels of antidepressant on the endocrine system in fish are sparse, the emerging evidence suggests that early-life exposure to these compounds have the potential to alter the developmental programming of the endocrine system, which could persist as long-term and multigenerational effects in teleosts.

The potential for adverse effects in fish exposed to antidepressants in the aquatic environment

Antidepressants are one of the most commonly prescribed pharmaceutical classes for the treatment of psychiatric conditions. They act via modulation of brain monoaminergic signaling systems (predominantly serotonergic, adrenergic, dopaminergic) that show a high degree of structural conservation across diverse animal phyla. A reasonable assumption, therefore, is that exposed fish and other aquatic wildlife may be affected by antidepressants released into the natural environment. Indeed, there are substantial data reported for exposure effects in fish, albeit most are reported for exposure concentrations exceeding those occurring in natural environments. From a critical analysis of the available evidence for effects in fish, risk quotients (RQs) were derived from laboratory-based studies for a selection of antidepressants most commonly detected in the aquatic environment. We conclude that the likelihood for effects in fish on standard measured end points used in risk assessment (i.e., excluding effects on behavior) is low for levels of exposure occurring in the natural environment. Nevertheless, some effects on behavior have been reported for environmentally relevant exposures, and antidepressants can bioaccumulate in fish tissues. Limitations in the datasets used to calculate RQs revealed important gaps in which future research should be directed to more accurately assess the risks posed by antidepressants to fish. Developing greater certainty surrounding risk of antidepressants to fish requires more attention directed toward effects on behaviors relating to individual fitness, the employment of environmentally realistic exposure levels, on chronic exposure scenarios, and on mixtures analyses, especially given the wide range of similarly acting compounds released into the environment.

Prescribed aggression of fishes: Pharmaceuticals modify aggression in environmentally relevant concentrations

Traces of psychoactive substances have been found in freshwaters globally. Fish are chronically exposed to pollution at low concentrations. The changes of aggressive behaviour of chub (Squalius cephalus) were determined under the exposure to four psychoactive compounds (sertraline, citalopram, tramadol, methamphetamine) at environmentally relevant concentrations of 1 μg/L for 42 days. We tested whether (A) the behavioural effect of compounds varies within a single species; (B) there is a correlation between the individual brain concentration of the tested pollutants and fish aggression using the novel analysis of pollutants in brain; and (C) there is detectable threshold to effective pollutant concentration in brain. Behaviour and pollutant concentrations in brain were determined repeatedly (1st, 7th, 21st, 42nd and 56th days), including a two-week-long depuration period. The effect of particular compounds varied. Citalopram and methamphetamine generally increased the fish aggression, while no such effect was found after exposure to tramadol or sertraline. The longitudinal analysis showed an aggression increase after depuration, indicating the presence of withdrawal effects in methamphetamine- and tramadol-exposed fish. The analysis of pollutant concentration in brain revealed a positive linear relationship of citalopram concentration and aggression, while no such effect was detected for other compounds and/or their metabolites. Structural break analyses detected concentration thresholds of citalopram (1 and 3 ng/g) and sertraline (1000 ng/g) in brain tissue, from which a significant effect on behaviour was manifested. While the effect of sertraline was not detected using traditional approaches, there was a reduction in aggression after considering its threshold concentration in the brain. Our results suggest that pursuing the concentration threshold of psychoactive compounds can help to reduce false negative results and provide more realistic predictions on behavioural outcomes in freshwater environments, especially in the case of compounds with bioaccumulation potential such as sertraline.

A two-year study of emerging micro-pollutants and drugs of abuse in two Western Cape wastewater treatment works (South Africa)

This study evaluated the occurrence and fate of fourteen contaminants of emerging concern (CECs) at two South African wastewater treatment works (WWTW). Daily loads of the drug targets were calculated in the aqueous phase of influent- and effluent wastewater to evaluate their fate at the treatment works, along with population-normalised daily loads in raw influent wastewater to identify community-wide substance use patterns in the two study areas. Environmental risk characterisation of the CECs at WWTW effluent discharge was done using conventional risk quotient (RQ) estimations. A significant reduction of most CECs was observed at both WWTW locations, except for some that have been previously recorded to persist through various WWTW processes globally, including the illicit drug methaqualone that was reported here for the first time to evaluate its fate during wastewater treatment, substance use trends, and potential toxicological risk. Moderate-to high-RQs were estimated for several target CECs during the sampling period for both treatment facilities. The results presented here suggest the need for a multi-disciplinary approach to WWTW monitoring of CECs and highlight the need for further refinement of risk assessment approaches to mitigate recalcitrant- or pseudo-persistent CECs in wastewater discharge. Such refinement should include: (1) identifying the potential ecological risk on a wider range of sentinel indicators, (2) interaction of CECs with various biochemical pathways (including sub-lethal toxicity responses), (3) identifying the persistence and toxicological risks of breakdown products and (4) partitioning of CECs in the aqueous environment and/or bioaccumulation in freshwater biota.

Sex Reversal and Performance in Fitness-Related Traits During Early Life in Agile Frogs

Sex reversal is a mismatch between genetic sex (sex chromosomes) and phenotypic sex (reproductive organs and secondary sexual traits). It can be induced in various ectothermic vertebrates by environmental perturbations, such as extreme temperatures or chemical pollution, experienced during embryonic or larval development. Theoretical studies and recent empirical evidence suggest that sex reversal may be widespread in nature and may impact individual fitness and population dynamics. So far, however, little is known about the performance of sex-reversed individuals in fitness-related traits compared to conspecifics whose phenotypic sex is concordant with their genetic sex. Using a novel molecular marker set for diagnosing genetic sex in agile frogs (Rana dalmatina), we investigated fitness-related traits in larvae and juveniles that underwent spontaneous female-to-male sex reversal in the laboratory. We found only a few differences in early life growth, development, and larval behavior between sex-reversed and sex-concordant individuals, and altogether these differences did not clearly support either higher or lower fitness prospects for sex-reversed individuals. Putting these results together with earlier findings suggesting that sex reversal triggered by heat stress may be associated with low fitness in agile frogs, we propose the hypothesis that the fitness consequences of sex reversal may depend on its etiology.

Monitoring of emerging contaminants of concern in the aquatic environment: a review of studies showing the application of effect-based measures

Water scarcity is increasingly a global cause of concern mainly due to widespread changes in climate conditions and increased consumptive water use driven by the exponential increase in population growth. In addition, increased pollution of fresh water sources due to rising production and consumption of pharmaceuticals and organic chemicals will further exacerbate this concern. Although surface water contamination by individual chemicals is often at very low concentration, pharmaceuticals for instance are designed to be efficacious at low concentrations, creating genuine concern for their presence in freshwater sources. Furthermore, the additive impact of multiple compounds may result in toxic or other biological effects that otherwise will not be induced by individual chemicals. Globally, different legislative frameworks have led to pre-emptive efforts which aim to ensure good water ecological status. Reports detailing the use and types of effect-based measures covering specific bioassay batteries that can identify specific mode of actions of chemical pollutants in the aquatic ecosystem to evaluate the real threat of pollutants to aquatic lives and ultimately human lives have recently emerged from monitoring networks such as the NORMAN network. In this review, we critically evaluate some studies within the last decade that have implemented effect-based monitoring of pharmaceuticals and organic chemicals in aquatic fauna, evaluating the occurrence of different chemical pollutants and the impact of these pollutants on aquatic fauna with special focus on pollutants that are contaminants of emerging concern (CEC) in urban wastewater. A critical discussion on studies that have used effect-based measures to assess biological impact of pharmaceutical/organic compound in the aquatic ecosystem and the endpoints measurements employed is presented. The application of effect-based monitoring of chemicals other than assessment of water quality status is also discussed.

Effect of seasonal variation on the occurrences of high-risk pharmaceutical in drain-laden surface water: A risk analysis of Yamuna River

The occurrence of pharmaceutical residues in the aquatic ecosystem is an emerging concern of environmentalists. This study primarily investigated the seasonal variation of high-priority pharmaceutical residues in the Yamuna River, accompanied by 22 drains discharge from different parts of Delhi. Five sampling sites were selected for analyzing high-priority pharmaceuticals along with physico-chemical and biological parameters for 3 season's viz. pre-monsoon (PrM), monsoon (DuM), and post-monsoon (PoM), respectively. The maximum occurrences were detected during the PoM, compared to the PrM and DuM seasons. The maximum concentration of BOD, COD, and Phosphate was detected at the last sampling station (SP-5). Similarly, all targeted pharmaceuticals concentration were maximum at the last sampling point i.e. Okhla barrage (SP-5, max: DIC = 556.1 ng/l, IBU = 223.4 ng/l, CAR = 183.1 ng/l, DIA = 457.8 ng/l, OFL = 1726.5 ng/l, FRU = 312.2 ng/l and SIM = 414.9 ng/l) except at Barapulla downstream (SP-4, max: ERY = 178.1 ng/l). The mean concentrations of Fecal coliform (FC) ranged from 1700 to 6500 CFU/100 ml. The maximum colonies were detected in PrM season (6500 CFU/100 ml) followed by PoM (5800 CFU/100 ml) and least in DuM (1700 CFU/100 ml). Risk quotient (RQ) analysis of high-priority pharmaceuticals indicated high ecotoxicological risks exposure (>1) from DIC, DIA, OFL, and SIM in all seasons at all the sampling sites. However, lower risk was predicted for IBU, CAR, ERY, and FRU, respectively. This risk assessment indicated an aquatic ecosystem potentially exposed to high risks from these pharmaceutical residues. Moreover, seasonal agricultural application, rainfall, and temperature could influence the levels and compositions of pharmaceutical residue in the aquatic ecosystem. Hence, attention is required particularly to this stream since it is only a local lifeline source for urban consumers for domestic water supply and farmers for cultivation.

Effects of the antidepressant mirtazapine on the swimming behaviour and gene expression rate of Danio rerio embryos - Is the sedating effect seen in humans also evident for fish?

In the last decade, mirtazapine has become an important antidepressant in clinical use and has also been found at many different environmental sampling sites. Several homologies between the zebrafish Danio rerio and humans, combined with a number of advantages for behavioural and gene expression research using zebrafish embryos, make their use for the analysis of mirtazapine appropriate. The sedative effect of mirtazapine in humans was also found for a specific concentration range in zebrafish embryos (1333.4 μg/L - 2666.9 μg/L). Specifically, 116 hpf old zebrafish embryos showed a reduced swimming distance when exposed to 1334.4 μg/L mirtazapine. Furthermore, changes at the gene regulatory level could be measured (1333.4 μg/L), in particular in the superordinate regulatory systems. For selected transporters of all regulatory systems, an up regulation of the genes by a factor of more than five times could be measured at the highest mirtazapine exposure concentration that was tested. Finally, studies on the protein levels demonstrated an increase in acetylcholinesterase activity for several exposure concentrations (83.3 μg/L and 666.7 μg/L). The physiological changes in zebrafish embryos caused by mirtazapine demonstrate the relevance of these types of studies in aquatic non-target organisms. Such neuroactive substances could pose a potential risk for aquatic organisms below the previously considered concentration threshold for morphological effects.

Human Drug Pollution in the Aquatic System: The Biochemical Responses of Danio rerio Adults

Simple Summary

The release of medicinal products for human use in the aquatic environment is now a serious problem, and can be fatal for the organisms that live there. Danio rerio is a freshwater fish that provides the possibility to study the effects of these pollutants on the health of aquatic organisms. The results of the various existing scientific studies are scarce and conflicting. Here, we review the scientific studies that have analyzed these effects, highlighting that the impacts of drugs are evident in the biochemical responses of these animals.

Abstract

To date, drug pollution in aquatic systems is an urgent issue, and Danio rerio is a model organism to study the toxicological effects of environmental pollutants. The scientific literature has analyzed the effect of human drug pollution on the biochemical responses in the tissues of D. rerio adults. However, the information is still scarce and conflicting, making it difficult to understand its real impact. The scientific studies are not consistent with each other and, until now, no one has grouped their results to create a baseline of knowledge of the possible impacts. In this review, the analysis of literature data highlights that the effects of drugs on adult zebrafishes depend on various factors, such as the tissue analyzed, the drug concentration and the sex of the individuals. Furthermore, the most influenced biochemical responses concern enzymes (e.g., antioxidants and hydrolase enzymes) and total protein and hormonal levels. Pinpointing the situation to date would improve the understanding of the chronic effects of human drug pollution, helping both to reduce it in the aquatic systems and then to draw up regulations to control this type of pollution.

Atresia of ovarian follicles in fishes, and implications and uses in aquaculture and fisheries

Atresia of ovarian follicles, that is the degenerative process of germ cells and their associated somatic cells, is a complex process involving apoptosis, autophagy and heterophagy. Follicular atresia is a normal component of fish oogenesis and it is observed throughout the ovarian cycle, although it is more frequent in regressing ovaries during the postspawning period. An increased occurrence of follicular atresia above physiological rates reduces fish fecundity and even causes reproductive failure in both wild and captive-reared fish stocks, and hence, this phenomenon has a wide range of implications in applied sciences such as fisheries and aquaculture. The present article reviews the available literature on both basic and applied traits of oocyte loss by atresia, including its morpho-physiological aspects and factors that cause a supraphysiological increase of follicular atresia. Finally, the review presents the use of early follicular atresia identification in the selection process of induced spawning in aquaculture and the implications of follicular atresia in fisheries management.

Predicting Micropollutant Removal by Reverse Osmosis and Nanofiltration Membranes: Is Machine Learning Viable?

Predictive models for micropollutant removal by membrane separation are highly desirable for the design and selection of appropriate membranes. While machine learning (ML) models have been applied for such purposes, their reliability might be compromised by data leakage due to inappropriate data splitting. More importantly, whether ML models can truly understand the mechanisms of membrane separation has not been revealed. In this study, we evaluate the capability of the XGBoost model to predict micropollutant removal efficiencies of reverse osmosis and nanofiltration membranes. Our results demonstrate that data leakage leads to falsely high prediction accuracy. By utilizing a model interpretation method based on the cooperative game theory, we test the knowledge of XGBoost on the mechanisms of membrane separation via quantifying the contributions of input variables to the model predictions. We reveal that XGBoost possesses an adequate understanding of size exclusion, but its knowledge of electrostatic interactions and adsorption is limited. Our findings suggest that future work should focus more on avoiding data leakage and evaluating the mechanistic knowledge of ML models. In addition, high-quality data from more diverse experimental conditions, as well as more informative variables, are needed to improve the accuracy of ML models for predicting membrane performance.

Occurrence and risk assessment of pharmaceuticals and cocaine around the coastal submarine sewage outfall in Guarujá, São Paulo State, Brazil

The aim of this study was to screen and quantify 23 pharmaceutical compounds (including illicit drugs), at two sampling points near the diffusers of the Guarujá submarine outfall, State of São Paulo, Brazil. Samples were collected in triplicate during the high (January 2018) and low (April 2018) seasons at two different water column depths (surface and bottom). A total of 10 compounds were detected using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Caffeine (42.3-141.0 ng/L), diclofenac (3.6-85.7 ng/L), valsartan (4.7-14.3 ng/L), benzoylecgonine (0.3-1.7 ng/L), and cocaine (0.3-0.6 ng/L) were frequently detected (75% occurrence). Orphenadrine (0.6-3.0 ng/L) and atenolol (0.1-0.3 ng/L), and acetaminophen (1.2-1.4 ng/L) and losartan (0.7-3.4 ng/L), were detected in 50% and 25% of the samples, respectively. Only one sample (12.5%) detected the presence of carbamazepine (< 0.001-0.1 ng/L). Unexpectedly a lower frequency of occurrence and concentration of these compounds occurred during the summer season, suggesting that other factors, such as the oceanographic and hydrodynamic regimes of the study area, besides the population rise, should be taken into account. Caffeine presented concentrations above the surface water safety limits (0.01 μg/L). For almost all compounds, the observed concentrations indicate nonenvironmental risk for the aquatic biota, except for caffeine, diclofenac, and acetaminophen that showed low to moderate ecological risk for the three trophic levels tested.

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.

Environmentally relevant concentrations of carbamazepine induced lipid metabolism disorder of Chinese rare minnow (Gobiocypris rarus) in a gender-specific pattern

Carbamazepine (CBZ), an anticonvulsant and mood stabilizer, is ubiquitous distributed in aquatic environment. Though the toxicity and endocrine disrupting effect of CBZ on non-target organisms have been studied, its lipotoxity are scarcely known. To assess the lipotoxicity of CBZ, 2-month-old Chinese rare minnow were exposed to 0, 1, 10, and 100 μg/L CBZ for 90 d. Obvious dyslipidemia was observed after 30 d and 90 d exposure, whereas overt hyperlipidemia was observed in males at 100 μg/L treatments. Severe lipid droplet accumulation in livers was observed at 10 and 100 μg/L treatments for 30 d and in females, whereas those was observed at all treatments in males. In addition, serious mitochondria damage was observed in males at 100 μg/L treatments. After 90 d exposure, the enzyme activities of FAS and ACCα were significantly increased at 10 and 100 μg/L treatments, whereas HMGCR were markedly increased at 100 μg/L treatments (p < 0.05). However, ACCβ were markedly decreased in females at 10 and 100 μg/L treatments and in males at all treatments (p < 0.05). The transcription levels of fasn, accα, hmgcrα, fdft1, idi1, plin1, plin2, caveolin1, and caveolin2 were significantly increased at 100 μg/L treatments (p < 0.05). Moreover, the body weight was obviously increased at 10 and 100 μg/L treatments in males (p < 0.05). Our results confirmed that environmental relevant concentrations CBZ induced lipid metabolism disorder and mitochondria damage of Chinese rare minnow in a gender-specific pattern, which provided a new insight into the lipotoxicity mechanism of CBZ.

Chronic exposure to anthropogenic and climate related stressors alters transcriptional responses in the liver of zebrafish (Danio rerio) across multiple generations

The antidepressant, venlafaxine (VFX), and climate change stressors, such as increased water temperature and decreased dissolved oxygen, are current threats to aquatic environments. This study aimed to determine how microRNAs (miRNAs) and predicted targeted transcripts were altered in livers of zebrafish exposed to these stressors, and livers of their un-exposed F₁ and F₂ offspring. Following a 21 day exposure to multiple stressors (1 μg/L VFX, +5 °C ambient, 50% O₂), then a subsequent 21 day recovery, relative abundances of cyp3a65, hsp70, hsp90, and ppargc1a and miRNAs predicted to target them (miR-142a, miR-16c, miR-181c, and miR-129, respectively) were measured in the liver via quantitative PCR (RT-qPCR). There were significant decreases in miR-142a in the exposed F₀ generation and the exposed F₁ generation. While there were no changes detected in cyp3a65 relative abundance, there was a significant inverse relationship between cyp3a65 and miR-142a. Hsp70 expression significantly increased in the F₁ generation, which persisted to the F₂ generation and the relative abundance of hsp90 significantly increased in all generations. There was a significant reduction in miR-181c in the F₁ generation, but there was no significant relationship between miR-181c and hsp90. Finally, there was a significant decrease in ppargc1a relative abundance in the F₁ generation which was associated with an increase in miR-129. Combined, these results suggest that parental exposure to multiple, environmentally relevant stressors can confer transcriptional and epigenetic responses in the F₁ and F₂ generations, although identifying which stressor is a driving force becomes unclear.