Are pharmaceuticals with evolutionary conserved molecular drug targets more potent to cause toxic effects in non-target organisms?

Critical insights into the potential risks of antipsychotic drugs to fish, including through effects on behaviour

Antipsychotic drugs (APDs) are a diverse class of neuroactive pharmaceuticals increasingly detected in surface and ground waters globally. Some APDs are classified as posing a high environmental risk, due, in part, to their tendency to bioaccumulate in wildlife, including fish. Additional risk drivers for APDs relate to their behavioural effects, potentially impacting fitness outcomes. However, standard ecotoxicological tests used in environmental risk assessment (ERA) do not currently account for these mechanisms. In this review, we critically appraise the environmental risks of APDs to fish. We begin by reading-across from human and mammalian effects data to standard ecotoxicological effects endpoints in fish. We then explore the wide range of behaviours suitable for ecotoxicological assessment of APDs (and other neuroactive) pharmaceuticals, principally through laboratory studies with zebrafish, and assess the potential for using these behavioural phenotypes to predict adverse individual- and population-level outcomes in wild fish, taking into account phenotypic plasticity. Next, we illustrate the advantages and challenges of measuring and applying behavioural endpoints for fish, including within current regulatory risk assessments. In our final analysis, the implications of relying on apical endpoints for ERA of neuroactive drugs (including APDs) are assessed and recommendations provided for the development of a more refined and tailored mechanistic approach, which would enable more robust assessment of their environmental risk(s).

Enantioselective ecotoxicity of promethazine in two freshwater organisms: daphnia (Daphnia magna) and zebrafish (Danio rerio)

Chiral pharmaceuticals, racemic or enantiomerically pure forms and their metabolites, can reach aquatic ecosystems via wastewater effluents (inefficient treatment operations) or by direct human disposal. They may negatively affect nontarget organisms even at low environmental concentrations. To make an accurate risk evaluation, the (eco)toxicity of both enantiomers needs to be assessed. Promethazine (PMZ) is a chiral antihistamine that has been detected in aquatic ecosystems owing to its high consumption. Promethazine undergoes metabolism in the liver, producing chiral metabolites such as promethazine sulfoxide (PMZSO) and N-desmethylpromethazine (DMPMZ) that reach water bodies. However, knowledge regarding the enantioselective toxicity of PMZ and its metabolites on aquatic organisms is missing. This study aimed to explore the potential enantioselective toxicity of PMZ and its metabolites on two relevant freshwater organisms, daphniid and fish, representing different trophic levels. The half maximal effect concentrations (EC50s) in Daphnia magna of PMZ, DMPMZ, and PMZSO were 2.33, 2.31, > 4 mg L-1, respectively, > 4 and 2.50 mg L-1 for (R) and (S)-PMZ, respectively, and > 4 mg L-1 for the enantiomers of DMPMZ and PMZSO. In studies involving zebrafish, Danio rerio, (R, S)-PMZ showed a median lethal concentration (LC50) of .72 mg L-1, and specific assays revealed that (R)-PMZ exhibited more pronounced adverse effects on larvae at the embryonic, morphological, and biochemical level than the racemate and (S)-PMZ. Toxicity and potential bioaccumulation of these compounds in daphniids and fish were also conducted using in silico tests through proprietary software. The results revealed a concordance between the experimental and predicted EC50 and LC50 values in both species.

Influence of polystyrene nanoplastics on the toxicity of haloperidol to amphibians: An in vivo and in vitro approach

Chemical pollution is a major driver for the current worldwide crisis of amphibian decline. The present study aimed to assess the influence of polystyrene nanoplastics (PS-NPLs) on the toxicity of haloperidol to aquatic life stages of amphibians, by using in vivo (tadpoles of Xenopus laevis and Pelophylax perezi) and in vitro (A6 and XTC-2 cell lines of X. laevis) biological models. Tadpoles of both species were exposed, for 96 h, to haloperidol: 0.404 to 2.05 mg l-1 (X. laevis) or 0.404 to 3.07 mg L-1 (P. perezi). The most sensitive species to haloperidol (X. laevis) was exposed to haloperidol's LC50,96h combined with two PS-NPLs concentrations (0.01 mg L-1 or 10 mg L-1); the following endpoints were monitored: mortality, malformations, body lengths and weight. In vitro cytotoxicity was assessed by exposing the two cell lines, for 72 h, to: haloperidol (0.195 to 100 mg L-1) alone and combined with 0.01 mg L-1 or 10 mg L-1 of PS-NPLs. Xenopus laevis tadpoles revealed a higher lethal and sublethal sensitivity to haloperidol than those of P. perezi, with LC50,96h of 1.45 and 2.20 mg L-1. In vitro assays revealed that A6 cell line is more sensitive haloperidol than XTC-2: LC50,72h of 13.2 mg L-1 and 5.92 mg L-1, respectively. Results also suggested a higher sensitivity of in vivo models when compared to in vitro biological. Overall, PS-NPLs did not influence haloperidol's toxicity for in vivo and in vitro biological models, except for a reduction on the incidence of malformations while increasing the lethal toxicity (at the lowest concentration) in tadpoles. These opposite interaction patterns highlight the need for a deeper comprehension of NPLs and pharmaceuticals interactions. Results suggest a low risk of haloperidol for anuran tadpoles, though in the presence of PS-NPLs the risk may be increased.

Effects of acetaminophen exposure on behavior and erythrocyte nuclear morphology of juvenile Oreochromis niloticus

The occurrence of pharmaceuticals in the environment can have undesirable effects on nontarget animals, including fish. The present experiment assessed the effects of subchronic exposure to waterborne acetaminophen (N-acetyl-p-aminophenol) (APAP) on selected behavioral aspects (physical avoidance response, ventilation rate, and food detection rate) and erythrocyte nuclear abnormality (ENA) in juvenile Oreochromis niloticus. Two groups of fish were exposed to APAP dissolved in aged municipal water (T1: 2 mg/L and T2: 10 mg/L) for 8 weeks in three replicates (n = 7 fish per tank), alongside a control group (C) without APAP. APAP-exposed fish spent significantly (p < .05) longer time to detect food (T1: 32.6 ± 4.55 s and T2: 39.6 ± 4.66 s) compared to the control group (19.9 ± 2.46 s). Both APAP-exposed groups exhibited attenuated physical avoidance responses (76.7%, 68.7%, and 87.3% in T1, T2, and C, respectively) and a lower mean ventilation rate compared to the control group (194.5 ± 15.5, 179.1 ± 11.6, and 233.2 ± 19.0 per min in T1, T2, and C, respectively). The frequency occurrence of ENA types such as bi-nucleated, notched nuclei, lobed nuclei, and blebbed nuclei (except micronuclei) was significantly higher (p < .05) in APAP-exposed groups compared to the control, with more pronounced effects in the T2 group. The study concludes that APAP exposure prompts significant alterations in behavior and erythrocyte nuclear morphology, emphasizing the value of monitoring and regulating the entry of pharmaceuticals, including APAP, into aquatic environments to prevent unintended effects on non-target organisms like Oreochromis niloticus.

Impact of Benzodiazepine Delorazepam on Growth and Behaviour of Artemia salina Nauplii

Benzodiazepines, a significant group of newly recognised water contaminants, are psychotropic medications prescribed for common anxiety symptoms and sleep disorders. They resist efficient degradation during sewage treatment and endure in aquatic environments. Their presence in aquatic matrices is increasing, particularly after the recent pandemic period, which has led many people to systematically use benzodiazepines to manage anxiety. In previous studies, an important interference of this class of drugs on both the larval and adult stages of some aquatic species has been demonstrated, with effects on behaviour and embryonic development. This study examined the influence of delorazepam, a diazepam metabolite, on Artemia salina development to gain insight into responses in naupliar larvae. Results demonstrated that treatments (1, 5, and 10 µg/L) increase the hatching percentage and induce a desynchronisation in growth. Mortality was only slightly increased (close to 10% at six days post-hatching), but lipid reserve consumption was modified, with the persistence of lipid globules at the advanced naupliar stages. Locomotory activity significantly decreased only at 10 µg/L treatment. No teratogenic effects were observed, though modest damages were noticed in the posterior trunk and eyes, two targets of environmental toxicity. The negative impact of delorazepam on Artemia salina adds to those already reported in other species of invertebrates and vertebrates, which are not yet considered targets of these drugs. This study underscores the need for further research and immediate attention to this class of contaminants and the importance of monitoring their presence during environmental risk assessments.

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.

Structural and functional damage to the retina and skeletal muscle in Xenopus laevis embryos exposed to the commonly used psychotropic benzodiazepine delorazepam

Benzodiazepines, psychotropic drugs, are among the most frequently found pharmaceuticals in aquatic matrices. An increasing number of studies are reporting their harmful effects on adults' behaviour and physiology, while little information is available regarding developing organisms exposed since early stages. Improper activation of GABA receptors during embryonic development is likely to induce relevant consequences on the morphogenesis and, at later stages, on behaviour. This study investigated the negative effects of three increasing concentrations of delorazepam on Xenopus laevis retinal and skeletal muscle morphogenesis. Morphological and ultrastructural investigations were correlated with gene expression, while Raman spectroscopy highlighted the main biochemical components affected. Conventional phototactic response and orientation in the magnetic field were assessed as indicators of proper interaction between sensory organs and the nervous system. Results confirm the profound impact of delorazepam on development and return an alarming picture of the amphibians' survival potentialities in a benzodiazepine-contaminated environment.

Does thermal stress modulate the biochemical and physiological responses of Ruditapes decussatus exposed to the progestin levonorgestrel?

In this study, we investigated the effects of 1000 ng/l levonorgestrel (LNG) alone or combined with increased temperature of 20, 24, and 28 °C on the biochemical and physiological responses of the clam (Ruditapes decussatus) for 28 days. Our results revealed that female clams treated with levonorgestrel (LNG) alone showed enhancement of the antioxidant defense against oxidative stress related to the inductions of catalase (CAT), gluthatione -S -transferase (GST), and protein sulfhydryl (PSH), while the elevated temperatures of 20, 24, and 28 °C diminished most of the specific responses to LNG and was the main factor in the determining the responses to combine exposures. The responses of lysosomal membrane stability, alkaline phosphatase, and NADP⁺-dependent isocitrate dehydrogenase detected were the most common signs of an adverse effect in all exposures. Female clams' testosterone and estradiol responses to LNG were the most particular manifestations depending on the exposure. Overall, these findings showed clearly that chronic warming stress caused disruption in physiological, biochemical parameters of the female clam R. decussatus, and this may have implications for the whole organism and populations.

Acute Toxicity of a Marine Emerging Pollutant (Promethazine Hydrochloride) on Artemia sp

Recently, there has been a worrying increase in the pollution of the aquatic ecosystem caused by emerging contaminants (ECs) detected in wastewater effluent discharges. Although traces of ECs in waters have been found in low concentrations, it leads to negative effects for nontarget organisms. Antihistamines are a class of drugs largely used, whose metabolites are widespread in the aquatic ecosystem. The aim of the study was to evaluate the short-term effects of promethazine hydrochloride on nauplii of Artemia sp. A high percentage of mortality and morphological alterations were found. The results suggest a possible correlation between exposure to antihistamine and an acceleration of larval development.

Reciprocal interactions between anthropogenic stressors and insect microbiota

Insects play many important roles in nature due to their diversity, ecological role, and impact on agriculture or human health. They are directly influenced by environmental changes and in particular anthropic activities that constitute an important driver of change in the environmental characteristics. Insects face numerous anthropogenic stressors and have evolved various detoxication mechanisms to survive and/or resist to these compounds. Recent studies highligted the pressure exerted by xenobiotics on insect life-cycle and the important role of insect-associated bacterial microbiota in the insect responses to environmental changes. Stressor exposure can have various impacts on the composition and structure of insect microbiota that in turn may influence insect biology. Moreover, bacterial communities associated with insects can be directly or indirectly involved in detoxification processes with the selection of certain microorganisms capable of degrading xenobiotics. Further studies are needed to assess the role of insect-associated microbiota as key contributor to the xenobiotic metabolism and thus as a driver for insect adaptation to polluted habitats.

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.

Environmental concentrations of a delorazepam-based drug impact on embryonic development of non-target Xenopus laevis

Benzodiazepines, psychotropics drugs used for treating sleep disorders, anxiety and epilepsy, represent a major class of emerging water pollutants. As occurs for other pharmaceutical residues, they are not efficiently degraded during sewage treatment and persist in effluent waters. Bioaccumulation is already reported in fish and small crustaceans, but the impact and consequences on other "non-target" aquatic species are still unclear and nowadays of great interest. In this study, we investigated the effects of a pharmaceutical preparation containing the benzodiazepine delorazepam on the embryogenesis of Xenopus laevis, amphibian model species, taxa at high risk of exposure to water contaminants. Environmental (1 μg/L) and two higher (5 and 10 μg/L) concentrations were tested on tadpoles up to stage 45/46. Results demonstrate that delorazepam interferes with embryo development and that the effects are prevalently dose-dependent. Delorazepam reduces vitality by decreasing heart rate and motility, induces marked cephalic and abdominal edema, as well as intestinal and retinal defects. At the molecular level, delorazepam increases ROS production, modifies the expression of some master developmental genes and pro-inflammatory cytokines. The resulting stress condition significantly affects embryos' development and threatens their survival. Similar effects should be expected as well in embryos belonging to other aquatic species that have not been yet considered targets for these pharmaceutical residues.

Juvenile hormone synthesis and signaling disruption triggering male offspring induction and population decline in cladocerans (water flea): Review and adverse outcome pathway development

Juvenile hormone (JH) are a family of multifunctional hormones regulating larval development, molting, metamorphosis, reproduction, and phenotypic plasticity in arthropods. Based on its importance in arthropod life histories, many insect growth regulators (IGRs) mimicking JH have been designed to control harmful insects in agriculture and aquaculture. These JH analogs (JHAs) may also pose hazards to nontarget species by causing unexpected endocrine-disrupting (ED) effects such as molting and metamorphosis defects, larval lethality, and disruption of the sexual identity. This critical review summarizes the current knowledge of the JH-mediated effects in the freshwater cladoceran crustaceans such as Daphnia species on JHA-triggered endocrine disruptive outputs to establish a systematic understanding of JHA effects. Based on the current knowledge, adverse outcome pathways (AOPs) addressing the JHA-mediated ED effects in cladoceran leading to male offspring production and subsequent population decline were developed. The weight of evidence (WoE) of AOPs was assessed according to established guidelines. The review and AOP development aim to present the current scientific understanding of the JH pathway and provide a robust reference for the development of tiered testing strategies and new risk assessment approaches for JHAs in future ecotoxicological research and regulatory processes.

Aquatic concentration and risk assessment of pharmaceutically active compounds in the environment

Pharmaceutically active compounds are increasingly detected in raw and treated wastewater, surface water, and drinking water worldwide. These compounds can cause adverse effects to the ecosystem even at low concentrations and, to assess these impacts, toxicity tests are essential. However, the toxicity data are scarce for many PhACs, and when available, they are dispersed in the literature. The values of pharmaceuticals concentration in the environment and toxicity data are essential for measuring their environmental and human health risks. Thus this review verified the concentrations of pharmaceuticals in the aquatic environment and the toxicity related to them. The risk assessment was also carried out. Diclofenac, naproxen, erythromycin, roxithromycin, and 17β-estradiol presented a high environment risk and 17α-ethinylestradiol presented a high human health risk. This shows the potential of these pharmaceuticals to cause adverse effects to the ecosystem and humans and establishes the necessity of their removal through advanced technologies.

Long-term exposure of Daphnia magna to polystyrene microplastic (PS-MP) leads to alterations of the proteome, morphology and life-history

In the past years, the research focus on the effects of MP on aquatic organisms extended from marine systems towards freshwater systems. An important freshwater model organism in the MP field is the cladoceran Daphnia, which plays a central role in lacustrine ecosystems and has been established as a test organism in ecotoxicology. To investigate the effects of MP on Daphnia magna, we performed a chronic exposure experiment with polystyrene MP under strictly standardized conditions. Chronic exposure of D. magna to PS microparticles led to a significant reduction in body length and number of offspring. To shed light on underlying molecular mechanisms induced by microplastic ingestion in D. magna, we assessed the effects of PS-MP at the proteomic level, as proteins, e.g., enzymes, are especially relevant for an organism's physiology. Using a state-of-the-art mass spectrometry based approach, we were able to identify 28,696 different peptides, which could be assigned to 3784 different proteins. Using a customized bioinformatic workflow, we identified 41 proteins significantly altered in abundance (q-value <0.05) in the PS exposed D. magna. Among the proteins increased in the PS treated group were several sulfotransferases, involved in basic biochemical pathways, as well as GABA transaminase catalyzing the degradation of the neurotransmitter GABA. In the abundance decreased group, we found essential proteins such as the DNA-directed RNA polymerase subunit and other proteins connected to biotic and inorganic stress and reproduction. Strikingly, we further identified several digestive enzymes that are significantly downregulated in the PS treated animals, which could have interfered with the affected animal's nutrient supply. This may explain the altered morphological and life history traits of the PS exposed daphnids. Our results indicate that long-term exposure to PS microplastics, which are frequently detected in environmental samples, may affect the fitness of daphnids.

Environmental risk assessment and bioaccumulation of pharmaceuticals in a large urbanized estuary

We screened for the presence of 66 different pharmaceutical residues in surface waters and in multiple invertebrate and fish species of the Tejo estuary to produce an environmental risk assessment of individual pharmaceuticals and their mixtures, as well as evaluate the bioaccumulation of pharmaceuticals in one of Europe's largest estuarine systems. Sixteen pharmaceutical residues, from seven therapeutic classes, were detected in estuarine waters, with environmental mixture concentrations ranging from 42 to 1762 ng/L. Environmental risk assessment via the determination of risk quotients, demonstrated high ecological risk for the antibiotic amoxicillin and angiotensin II receptor blockers irbesartan and losartan. Moderate risk was estimated for antidepressants, antiepileptics, anxiolytics and beta-blockers, but the risk quotient of the accumulated mixture of compounds was over 380-fold higher than the no risk threshold, driven by antibiotics and angiotensin II receptor blockers. In biota, higher risk therapeutic groups were found in higher concentrations, with nine pharmaceutical residues detected, including six antibiotics and two neuroactive compounds, and maximum tissue concentrations up to 250 μg/kg. Bioaccumulation was species- and compound-specific, with only two compounds found simultaneously in water and biota, likely a result of the complex dynamics and fate of pharmaceuticals in estuarine waters. Nonetheless, higher detection frequencies were observed in species living directly on or just above the substrate (i.e. benthic and demersal species), underpinning the importance of habitat use, as well the potential role of sediment and diet based routes for pharmaceutical uptake. Ultimately, results support urgent action on managing the impact of pharmaceuticals in coastal environments, striving for improved monitoring schemes tailored to the dynamic nature and ecological diversity of estuaries and coastal ecosystems.

Potent antifungal agents and use of nanocarriers to improve delivery to the infected site: A systematic review

There are four major classes of antifungals with the predominant mechanism of action being targeting of cell wall or cell membrane. As in other drugs, low solubility of these compounds has led to low bioavailability in target tissues. Enhanced drug dosages have effects such as toxicity, drug-drug interactions, and increased drug resistance by fungi. This article reviews the current state-of-the-art of antifungals, structure, mechanism of action, other usages, and toxic side effects. The emergence of nanoformulations to transport and uniformly release cargo at the target site is a boon in antifungal treatment. The article details research that lead to the development of nanoformulations of antifungals and potential advantages and avoidance of the lacunae characterizing conventional drugs. A range of nanoformulations based on liposomes, polymers are in various stages of research and their potential advantages have been brought out. It could be observed that under similar dosages, test models, and duration, nanoformulations provided enhanced activity, reduced toxicity, higher uptake and higher immunostimulatory effects. In most instances, the mechanism of antifungal activity of nanoformulations was similar to that of regular antifungal. There are possibilities of coupling multiple antifungals on the same nano-platform. Increased activity coupled with multiple mechanisms of action presents for nanoformulations a tremendous opportunity to overcome antifungal resistance. In the years to come, robust methods for the preparation of nanoformulations taking into account the repeatability and reproducibility in action, furthering the studies on nanoformulation toxicity and studies of human models are required before extensive use of nanoformulations as a prescribed drug.

Cytotoxic responses of the anticancer drug cyclophosphamide in the mussel Mytilus galloprovincialis and comparative sensitivity with human cells lines

The rise of cancer cases worldwide led to an increase in production and consumption of anticancer drugs, that ultimately end up in the marine environment and are accumulated in aquatic organisms. Cyclophosphamide (CP) is a cytotoxic alkylating agent frequently prescribed in cancer treatments. This study assess ecotoxicological effects of CP on mussels Mytilus galloprovincialis, through in vivo and ex vivo approaches and compares the sensitivity of mussel haemocytes with well-established human cell lines (RPE and HeLa). Mussels were exposed in vivo to CP (1000 ng L^-1) and several biomarkers analysed in gills and digestive glands namely neurotoxicity (AChE activity), oxidative stress (GPx activity), biotransformation (GST activity), lipid peroxidation (LPO) and apoptosis (caspase activity), whereas genotoxicity was determined in mussels' haemocytes. Cytotoxicity was also assessed in haemocytes (in vivo and ex vivo) and human cell lines (in vitro) exposed to a range of CP concentrations (50, 100, 250, 500 and 1000 ng L^-1) over 24 h, via neutral red assay. In in vivo exposure, detoxification of CP did not efficiently occur in the gills while in digestive glands GPx and GST activities were induced, jointly with a decrease in lipid peroxidation, indicating a potential outcome of the protective antioxidant mechanisms, whereas no apoptosis was noted. Moreover, cytotoxicity and DNA damage were detected in haemocytes. The ex vivo exposure haemocytes to CP caused cytotoxicity (from 100 ng L^-1), whereas no effects occurred in human cell lines. This suggests that, at relevant environmental concentrations, CP cause subtle and irreversible impacts on M. galloprovincialis.

Chronic exposure of Brown (Hydra oligactis) and green Hydra (Hydra viridissima) to environmentally relevant concentrations of pharmaceuticals

Low concentrations of pharmaceuticals in the environment (ng/L to μg/L) are an environmental concern. We used the invertebrates, Hydra oligactis and Hydra viridissima, as freshwater models for primary toxicity testing to study effects of chronic low concentrations of pharmaceuticals in the environment. H. oligactis were exposed to three concentrations (0.1, 1.0 and 10 μg/L) of either fluoxetine, carbamazepine, or triclosan; H. viridissima were exposed to three concentrations (0.1, 1.0 and 10 μg/L) of triclosan. Ecologically relevant endpoints including morphology, budding rate, feeding behaviour, and regenerative capacity were examined during the 14 days exposure period. The interstitial:epithelial stem cell ratios was also examined in H. oligactis. There were no significant effects on the morphology, budding rate and feeding behaviour of the H. oligactis across all concentrations of fluoxetine, carbamazepine, and triclosan. However, regenerative capacity significantly decreased in comparison to the controls when H. oligactis was exposed to 10 μg/L of triclosan and fluoxetine, although there was no significant difference when exposed to carbamazepine. Neither fluoxetine nor carbamazepine treatment altered stem cell ratios. Exposure to triclosan at any concentration did not impact H. viridissima morphology, budding rate, regeneration or feeding behaviour. These results show there are limited effects in Hydra after exposure to chronic, low concentrations of fluoxetine, carbamazepine, and triclosan, except for regeneration in H. oligactis. These endpoints can be used effectively (and cost effectively) to study the effects of environmentally relevant concentrations of pharmaceuticals in Hydra species.

Calmodulin inhibition as a mode of action of antifungal imidazole pharmaceuticals in non-target organisms

To improve assessment of risks associated with pharmaceutical contamination of the environment, it is crucial to understand effects and mode of action of drugs in non-target species. The evidence is accumulating that species with well-conserved drug targets are prone to be at risk when exposed to pharmaceuticals. An interesting group of pharmaceuticals released into the environment is imidazoles, antifungal agents with inhibition of ergosterol synthesis as a primary mode of action in fungi. However, imidazoles have also been identified as competitive antagonists of calmodulin (CaM), a calcium-binding protein with phylogenetically conserved structure and function. Therefore, imidazoles would act as CaM inhibitors in various organisms, including those with limited capacity to synthesize sterols, such as arthropods. We hypothesized that effects observed in crustaceans exposed to imidazoles are related to the CaM inhibition and CaM-dependent nitric oxide (NO) synthesis. To test this hypothesis, we measured (i) CaM levels and its gene expression, (ii) NO accumulation and (iii) gene expression of NO synthase (NOS1 and NOS2), in the cladoceran Daphnia magna exposed to miconazole, a model imidazole drug. Whereas significantly increased CaM gene expression and its cellular allocation were observed, supporting the hypothesized mode of action, no changes occurred in either NO synthase expression or NO levels in the exposed animals. These findings suggest that CaM inhibition by miconazole leads to protein overexpression that compensates for the loss in the protein activity, with no measurable downstream effects on NO pathways. The inhibition of CaM in D. magna may have implications for effect assessment of exposure to mixtures of imidazoles in aquatic non-target species.

Impacts of in vivo and in vitro exposures to tamoxifen: Comparative effects on human cells and marine organisms

Tamoxifen (TAM) is a first generation-SERM administered for hormone receptor-positive (HER+) breast cancer in both pre- and post-menopausal patients and may undergo metabolic activation in organisms that share similar receptors and thus face comparable mechanisms of response. The present study aimed to assess whether environmental trace concentrations of TAM are bioavailable to the filter feeder M. galloprovincialis (100 ng L^-1) and to the deposit feeder N. diversicolor (0.5, 10, 25 and 100 ng L^-1) after 14 days of exposure. Behavioural impairment (burrowing kinetic), neurotoxicity (AChE activity), endocrine disruption by alkali-labile phosphate (ALP) content, oxidative stress (SOD, CAT, GPXs activities), biotransformation (GST activity), oxidative damage (LPO) and genotoxicity (DNA damage) were assessed. Moreover, this study also pertained to compare TAM cytotoxicity effects to mussels and targeted human (i.e. immortalized retinal pigment epithelium - RPE; and human transformed endothelial cells - HeLa) cell lines, in a range of concentrations from 0.5 ng L^-1 to 50 μg L^-1. In polychaetes N. diversicolor, TAM exerted remarkable oxidative stress and damage at the lowest concentration (0.5 ng L^-1), whereas significant genotoxicity was reported at the highest exposure level (100 ng L^-1). In mussels M. galloprovincialis, 100 ng L^-1 TAM caused endocrine disruption in males, neurotoxicity, and an induction in GST activity and LPO byproducts in gills, corroborating in genotoxicity over the exposure days. Although cytotoxicity assays conducted with mussel haemocytes following in vivo exposure was not effective, in vitro exposure showed to be a feasible alternative, with comparable sensitivity to human cell line (HeLa).

Environmental risk assessment of psychoactive drugs in the aquatic environment

The consumption of psychoactive pharmaceuticals has increased worldwide, and wastewater treatment plants are not able to eliminate them from the effluent. An extensive review was carried out to assess the environmental risk (ERA model) based on secondary data about potential impacts on non-target organisms of seven psychoactive drugs consumed worldwide (alprazolam, bromazepam, citalopram, clonazepam, diazepam, lorazepam, and oxazepam). Risk quotients (RQs) were calculated according to the European Medicines Agency (EMA) on ERA of Medicinal Products For Human Use based on (i) the predicted and measured environmental concentrations (PEC and MEC, respectively) of the psychoactive drug in surface water, groundwater, and wastewater effluent and (ii) the predicted no-effect concentration (PNEC) derived from ecotoxicological assays or ECOSAR software. Furthermore, this study reviews and discusses non-standardized ecotoxicity assays, such as sublethal and behavioral effects on different organisms. In total, 903 MEC entries of psychoactive drugs and 162 data on ecotoxicological assays were gathered from the literature survey addressing behavioral effects (115), acute/chronic effects (35), and sublethal effects (12). Citalopram and diazepam were the only substances that are likely to pose an environmental risk (RQ > 1) to surface waters. Even though there is considerable amount of data on behavioral effects of psychoactive drugs to aquatic species, results are currently not integrated into the EMA risk assessment framework. The large amount of data on psychoactive drug concentrations and effects on non-target organisms collected, interpreted, and discussed in the present study should be used as a baseline for future improvement of ERA strategies.

Pharmaceutical Mixtures: Still A Concern for Human and Environmental Health

In the present work, recent data on the sources, occurrence and fate of human-use pharmaceutical active compounds (PhACs) in the aquatic environment have been reviewed. Since PhACs and their metabolites are usually present as mixtures in the environment at very low concentrations, a particular emphasis was placed onto the PhACs mixtures, as well as on their short-term and long-term effects against human and environmental health. Moreover, a general overview of the main conventional as well as of the latest trends in wastewaters decontaminant technologies was outlined. Advantages and disadvantages of current processes were also pointed out. It appears that numerous gaps still exist in the current knowledge related to this field of interest, and further studies should be conducted at the global level in order to ensure a more efficient monitorisation of the presence of PhACs and their metabolites into the aquatic environment and to develop new mitigation measures.

Application of prioritization approaches to optimize environmental monitoring and testing of pharmaceuticals

Pharmaceuticals are ubiquitous in the natural environment with concentrations expected to rise as human population increases. Environmental risk assessments are available for a small portion of pharmaceuticals in use, raising concerns over the potential risks posed by other drugs that have little or no data. With >1900 active pharmaceutical ingredients in use, it would be a major task to test all of the compounds with little or no data. Desk-based prioritization studies provide a potential solution by identifying those substances that are likely to pose the greatest risk to the environment and which, therefore, need to be considered a priority for further study. The aim of this review was to (1) provide an overview of different prioritization exercises performed for pharmaceuticals in the environment and the results obtained; and (2) propose a new holistic risk-based prioritization framework for drugs in the environment. The suggested models to underpin this framework are discussed in terms of validity and applicability. The availability of data required to run the models was assessed and data gaps identified. The implementation of this framework may harmonize pharmaceutical prioritization efforts and ensure that, in the future, experimental resources are focused on molecules, endpoints, and environmental compartments that are biologically relevant.

Global scanning of antihistamines in the environment: Analysis of occurrence and hazards in aquatic systems

Concentration of the global population is increasingly occurring in megacities and other developing regions, where access to medicines is increasing more rapidly than waste management systems are implemented. Because freshwater and coastal systems are influenced by wastewater effluent discharges of differential quality, exposures in aquatic systems must be considered. Here, we performed a global scanning assessment of antihistamines (AHs), a common class of medicines, in surface waters and effluents. Antihistamines were identified, literature occurrence and ecotoxicology data on AHs collated, therapeutic hazard values (THVs) calculated, and environmental exposure distributions (EEDs) of AHs compared to ecotoxicity thresholds and drug specific THVs to estimate hazards in surface waters and effluents. Literature searches of 62 different AHs in environmental matrices identified 111 unique occurrence publications of 24 specific AHs, largely from Asia-Pacific, Europe, and North America. However, the majority of surface water (63%) and effluent (85%) observations were from Europe and North America, which highlights relatively limited information from many regions, including developing countries and rapidly urbanizing areas in Africa, Latin America and Asia. Less than 10% of all observations were for estuarine or marine systems, though the majority of human populations reside close to coastal habitats. EED 5^th and 95^th centiles for all AHs were 2 and 212ng/L in surface water, 5 and 1308ng/L in effluent and 6 and 4287ng/L in influent, respectively. Unfortunately, global hazards and risks of AHs to non-target species remain poorly understood. However, loratadine observations in surface waters exceeded a THV without an uncertainty factor 40% of the time, indicating future research is needed to understand aquatic toxicology, hazards and risks associated with this AH. This unique global scanning study further illustrates the utility of global assessments of pharmaceuticals and other contaminants to identify chemicals requiring toxicology study and regions where environmental monitoring, assessment and management efforts appear limited and necessary.

Endocrine-disruption potential of perfluoroethylcyclohexane sulfonate (PFECHS) in chronically exposed Daphnia magna

Perfluoroethylcyclohexane sulfonate (PFECHS), mainly used in hydraulic fluids in aircrafts, is a member of the perfluoroalkyl sulfonate family which includes the regulated perfluorooctane sulfonate (PFOS). PFECHS has been reported in environmental samples but its toxicity to aquatic organisms is unknown. The objectives of this study were to identify biological pathways altered by sublethal exposure (12 d) of D. magna to PFECHS (0.06, 0.6, and 6 mg/L) using microarray and quantitative real-time PCR and to identify potential biomarkers to link transcriptomic to phenotypic responses. PFECHS was also quantified in surface water samples (1.04-1.38 ng/L) collected from the St. Lawrence River, Canada. Transcriptomic analyses indicated the under-regulation of vitellogenin-related genes (VTG1) in PFECHS-exposed groups. PFECHS exposure also led to the up-regulation of genes related to cuticle. VTG was selected as a potential cellular marker and identified in D. magna using an immuno-specific assay and quantified using Western blot and LC/MS/MS. Results indicated a decrease of VTG content in exposed D. magna which was in concordance with the transcription of VTG-related genes. No effects were observed on survival, molting, or reproduction at the individual/population levels. Overall, results suggest endocrine disruption potential for PFECHS in D. magna at concentrations higher than levels reported in the aquatic environment.

Evaluation of acute effects of four pharmaceuticals and their mixtures on the copepod Tisbe battagliai

The individual and combined toxicities of acetaminophen, carbamazepine, diclofenac and ibuprofen have been examined in neonate nauplii (<24 h-old) of the harpacticoid copepod Tisbe battagliai. Based on acute toxicity data (LC50) obtained, diclofenac was the most toxic compound with an LC50 value of 9.5 mg·L(-1); this is between 5 and 7 times lower than the LC50 value for acetaminophen, carbamazepine and ibuprofen (67.8 mg·L(-1), 59 mg·L(-1) and 49.7 mg·L(-1) respectively). The environmental risk posed by the selected pharmaceuticals was assessed by calculating risk quotients (RQs) based on MEC (the highest exposure concentration of the compound in the medium)/PNEC (predicted no effect concentration) ratios. Results suggest that, at environmental concentrations, none of the compounds is harmful for the aquatic environment (low or no risk). Toxicity data obtained for mixtures were compared with predictions derived from three different models: Concentration Addition (CA), Independent Action (IA) and Combination Index (CI). The classical modeling approaches CA and IA failed to predict the observed mixture toxicity, thus indicating that single compound toxicity data are not sufficient to predict toxicity of drug mixtures on Tisbe species. However, the use of the CI seems to provide better predictions of pharmaceutical toxicity.

In vitro effects of the citrus flavonoids diosmin, naringenin and naringin on the hepatic drug-metabolizing CYP3A enzyme in human, pig, mouse and fish

Flavonoids are known to have effects on cytochrome P450 enzymatic activity. However, little effort has been made to examine species differences and the relevance of studies on mammalian and fish microsomes so that extrapolations can be made to humans. Therefore, the effects of several naturally occurring flavonoids on the activity of CYP3A-dependent 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylase (BFCOD) were evaluated in human, pig, mouse, and juvenile rainbow trout sources of hepatic microsomes. Each was exposed to three concentrations (1, 10, and 100μM) of diosmin, naringin, and naringenin. Naringenin competitively inhibited BFCOD activity (Ki values were 24.6μM in human, 15.6μM in pig, and 19.6μM in mouse microsomes). In fish, BFCOD activity was inhibited in a noncompetitive manner (Ki=7μM). Neither diosmin nor naringenin affected BFCOD activity in hepatic microsomes from the studied model organisms. These results suggest that dietary flavonoids potentially inhibit the metabolism of clinical drugs.