Selective uptake and biological consequences of environmentally relevant antidepressant pharmaceutical exposures on male fathead minnows

The use of immobilized artificial membrane chromatography to predict bioconcentration of pharmaceutical compounds

The potential of immobilized artificial membrane chromatography (IAM) to predict bioconcentration factors (BCF) of pharmaceutical compounds in aquatic organisms was studied. For this purpose, retention factors extrapolated to pure aqueous phase, logk_w(IAM), of 27 drugs were measured on an IAM stationary phase, IAM.PC.MG type. The data were combined with retention factors on two IAM columns, IAM.PC.MG and IAM.PC.DD2 types, reported previously by our research group and correlated with logBCF values predicted by Estimation Program Interface (EPI Suite) Software. Linear models were established upon exclusion of ionic or highly hydrophilic nonionic drugs, for which a constant value of logBCF equal to 0.50 was arbitrarily assigned by EPI Suite Software. As additional physicochemical parameter BioWin5 proved to be statistically significant, expressing the decrease of bioaccumulation potential as a result of biodegradation in the aquatic environment. The constructed IAM model was successfully validated by application to a set of pharmaceuticals, whose experimental BCF values are available. Better predictions compared to EPI Suite Software were achieved for the dataset under study. Since bioconcentration process involves electrostatic interactions, IAM retention may be a better measure for BCF values, especially for ionic species, compared to octanol-water partition coefficients widely implemented in environmental sciences. The developed approach can be considered as a novel tool for the prediction of bioconcentration of pharmaceutical compounds in aquatic organisms in order to minimize further experimental assays in the future.

Dose-dependent fluoxetine effects on boldness in male Siamese fighting fish

As the use of pharmaceuticals and personal care products (PPCPs) continues to rise, these compounds enter the environment in increasing frequency. One such PPCP, fluoxetine, has been found in detectable amounts in aquatic ecosystems worldwide, where it may interfere with the behavior of exposed organisms. Fluoxetine exposure has been found to influence boldness and exploration in a range of fish species; however, how it might alter behavior in multiple contexts or over time is rarely examined. To this end, the effects of fluoxetine on boldness over time were studied in male Siamese fighting fish. Three different groups of males (0, 0.5 and 5 µg l(-1) fluoxetine) were tested in multiple boldness assays (empty tank, novel environment and shoal) once a week for 3 weeks to collect baseline measures and then at three different time points post-exposure. The effects of these varying exposure amounts on behavior were then examined for overall response, consistency and across-context correlations. Unexposed males were bolder in all contexts, were more consistent within a context, and had stronger between-context correlations than exposed males. Fluoxetine had dose-dependent effects on behavior, as males that received the higher dose exhibited greater behavioral effects. This study stresses the potential fitness consequences of fluoxetine exposure and suggests that examining behavioral effects of PPCPs under different dosing regimens and in multiple contexts is important to gain an increased understanding of how exposure affects behavior.

The SSRI fluoxetine exhibits mild effects on the reproductive axis in the cichlid fish Cichlasoma dimerus (Teleostei, Cichliformes)

Among the wide variety of pharmaceuticals released into the environment, Fluoxetine (FLX), a selective serotonin reuptake inhibitor, is one of the most prescribed for the treatment of major depression. It inhibits serotonin (5-HT) reuptake at the presinaptic membrane, increasing serotonergic activity. In vertebrates, including fish, the serotonergic system is closely related to the Hypothalamic Pituitary Gonadal (HPG) axis which regulates reproduction. As FLX can act as an endocrine disrupting compound (EDC) by affecting several reproductive parameters in fish, the aim of this study was to provide an integral assessment of the potential effect of FLX on the reproductive axis of the Neotropical freshwater fish Cichlasoma dimerus. Adult fish were intraperitoneally injected with 2 μg g^-1 FLX or saline every third day for 15 days. No significant differences were found on serotonergic turnover (5-HIAA/5-HT ratio). Pituitary βLH content in FLX injected females was significantly higher than control females; no significant differences were seen for βFSH content. Sex steroids remained unaltered, both in males and females fish, after FLX treatment. No plasma vitellogenin was induced in treated males. Some alterations were seen in testes of FLX injected males, such as the presence of foam cells and an acidophilic PAS positive, Alcian-Blue negative secretion in the lobular lumen. Although there is no clear consensus about the effect of this drug on reproductive physiology, these results indicate that FLX is acting as a mild EDC in adults of C. dimerus.

Bioconcentration and Biotransformation of Amitriptyline in Gilt-Head Bream

Extensive global use of the serotonin-norepinephrine reuptake inhibitor Amitriptyline (AMI) for treatment of mental health problems has led to its common occurrence in the aquatic environment. To assess AMI bioconcentration factors, tissue distribution, and metabolite formation in fish, we exposed gilt-head bream (Sparus aurata) to AMI in seawater for 7 days at two concentrations (0.2 μg/L and 10 μg/L). Day 7 proportional bioconcentration factors (BCFs) ranged from 6 (10 μg/L dose, muscle) to 127 (0.2 μg/L dose, brain) and were consistently larger at the low dose level. The relative tissue distribution of AMI was consistent at both doses, with concentrations decreasing in the order brain ≈ gill > liver > plasma > bile ≫ muscle. Using a suspect screening workflow based on liquid chromatography-high resolution (Orbitrap) mass spectrometry we identified 33 AMI metabolites (both Phase I and Phase II), occurring mostly in bile, liver and plasma. Ten structures are reported for the first time. Remarkably, all 33 metabolites retained the tricyclic ring structure common to tricyclic antidepressants, which may be toxicologically relevant. Collectively these data indicate that, in addition to AMI, a broad suite of metabolites should be included in biomonitoring campaigns in order to fully characterize exposure in aquatic wildlife.

In vitro nuclear receptor activity and in vivo gene expression analysis in Murray-Darling rainbowfish (Melanotaenia fluviatilis) after short-term exposure to fluoxetine

Fluoxetine (FLX) is one of numerous pharmaceuticals found in treated municipal wastewater discharged to the environment. In the present study, we investigated the effects of short-term (96h) waterborne FLX exposure (1μg/L or 100μg/L) on the expression of selected genes in brain, liver, and gonads of female Murray-Darling rainbowfish (Melanotaenia fluviatilis), a small-bodied teleost of ecotoxicological relevance in the Australasia region. Plasma 17β-estradiol (E2) levels were also determined. In the brain, no significant changes in mRNA levels were observed for the selected genes. In ovaries, 100μg/L FLX caused a 10-fold downregulation of aromatase A (cyp19a1a) mRNA and a 4-fold upregulation of estrogen receptor α (esr1) mRNA levels. In liver, mRNA levels for vitellogenin A (vtga) and choriogenin L (chgl) were downregulated by 50-fold and 18-fold compared with controls, respectively, in response to 100μg/L FLX. Concentrations of E2 in plasma were significantly lower than controls in response to 100μg/L FLX. This could be attributable to a decrease in estrogen biosynthesis as a result of the observed downregulation of cyp19a1a mRNA. To establish whether the observed changes in gene expression could be explained by the modulation of selected nuclear receptors by FLX, we employed panel of reporter gene assays in agonistic and antagonistic modes. Apart from minor activation of ERα after exposure to high concentrations (5μM), FLX did not activate or inhibit the nuclear receptors tested. Further study is required to determine whether the observed downregulation of ovarian aromatase expression and liver estrogen-regulated genes also occurs at environmentally relevant FLX concentrations over longer exposure periods.

Danio rerio embryos on Prozac - Effects on the detoxification mechanism and embryo development

In the past decade the presence of psychopharmaceuticals, including fluoxetine (FLU), in the aquatic environment has been associated with the increasing trend in human consumption of these substances. Aquatic organisms are usually exposed to chronic low doses and, therefore, risk assessments should evaluate the effects of these compounds in non-target organisms. Teleost fish possess an array of active defence mechanisms to cope with the deleterious effects of xenobiotics. These include ABC transporters, phase I and II of cellular detoxification and oxidative stress enzymes. Hence, the present study aimed at characterising the effect of FLU on embryo development of the model teleost zebrafish (Danio rerio) concomitantly with changes in the detoxification mechanisms during early developmental phases. Embryos were exposed to different concentrations of FLU (0.0015, 0.05, 0.1, 0.5 and 0.8μM) for 80hours post fertilization. Development was screened and the impact in the transcription of key genes, i.e., abcb4, abcc1, abcc2, abcg2, cyp1a, cyp3a65, gst, sod, cat, ahr, pxr, pparα, pparβ, pparγ, rxraa, rxrab, rxrbb, rxrga, rxrgb, raraa, rarab, rarga evaluated. In addition, accumulation assays were performed to measure the activity of ABC proteins and antioxidant enzymes (CAT and Cu/ZnSOD) after exposure to FLU. Embryo development was disrupted at the lowest FLU concentration tested (0.0015μM), which is in the range of concentrations found in WWTP effluents. Embryos exposed to higher concentrations of FLU decreased Cu/Zn SOD, and increased CAT (0.0015 and 0.5μM) enzymatic activity. Exposure to higher concentrations of FLU decreased the expression of most genes belonging to the detoxification system and upregulated cat at 0.0015μM of FLU. Most of the tested concentrations downregulated pparα, pparβ, pparγ, and raraa, rxraa, rxrab, rxrbb rxrgb and ahr gene expression while pxr was significantly up regulated at all tested concentrations. In conclusion, this study shows that FLU can impact zebrafish embryo development, at concentrations found in effluents of WWTPs, concomitantly with changes in antioxidant enzymes, and the transcription of key genes involved in detoxification and development. These finding raises additional concerns supporting the need to monitor the presence of this compound in aquatic reservoirs.

The effects of bupropion on hybrid striped bass brain chemistry and predatory behavior

Increased use of antidepressants has led to an increase in their detection in final treated wastewater effluents and receiving streams. Antidepressants are intended to modify human behavior by altering brain chemistry, and because of the high functional conservation of antidepressant target receptors in vertebrates, aquatic organisms may be at risk. The antidepressant bupropion is designed to alter brain norepinephrine and dopamine concentrations in humans. The objective of the present study was to understand if alteration of dopaminergic neurotransmitter concentrations in the hybrid striped bass (Morone saxatilis × Morone chrysops) brain by bupropion would alter this predator's ability to capture prey. The authors exposed hybrid striped bass to bupropion in a static system for 6 d, followed by a 6-d recovery period. During the present study's 12-d experiment, each hybrid striped bass was fed 4 unexposed fathead minnows every 3 d, and the time it took the hybrid striped bass to consume each of those 4 fathead minnows was quantified. After each feeding event, hybrid striped bass brains were harvested and analyzed for changes in several brain neurotransmitter concentrations, including serotonin, norepinephrine, dopamine, and many of their metabolites. Although bupropion altered the concentration of dopamine and many of the dopaminergic neurotransmitter metabolite concentrations in the brains on day 3 of the exposure, it did not alter the time to capture prey. This suggests that alteration of dopaminergic neurotransmitter concentrations in the hybrid striped bass brain does not alter a predator's ability to capture prey. Environ Toxicol Chem 2016;35:2058-2065. © 2016 SETAC.

The effect of tramadol hydrochloride on early life stages of fish

The aim of this study was to perform the fish embryo acute toxicity test (FET) on zebrafish (Danio rerio) and the early-life stage toxicity test on common carp (Cyprinus carpio) with tramadol hydrochloride. The FET was performed using the method inspired by the OECD guideline 236. Newly fertilized zebrafish eggs were exposed to tramadol hydrochloride at concentrations of 10; 50; 100 and 200μg/l for a period of 144h. An embryo-larval toxicity test on C. carpio was performed according to OECD guideline 210 also with tramadol hydrochloride at concentrations 10; 50; 100 and 200μg/l for a period of 32 days. Hatching was significantly influenced in both acute and subchronic toxicity assays. Subchronic exposure also influenced early ontogeny, both morphometric and condition characteristics and caused changes in antioxidant enzyme activity. The LOEC value was found to be 10μg/l tramadol hydrochloride.

Contaminants of emerging concern in a large temperate estuary

This study was designed to assess the occurrence and concentrations of a broad range of contaminants of emerging concern (CECs) from three local estuaries within a large estuarine ecosystem. In addition to effluent from two wastewater treatment plants (WWTP), we sampled water and whole-body juvenile Chinook salmon (Oncorhynchus tshawytscha) and Pacific staghorn sculpin (Leptocottus armatus) in estuaries receiving effluent. We analyzed these matrices for 150 compounds, which included pharmaceuticals, personal care products (PPCPs), and several industrial compounds. Collectively, we detected 81 analytes in effluent, 25 analytes in estuary water, and 42 analytes in fish tissue. A number of compounds, including sertraline, triclosan, estrone, fluoxetine, metformin, and nonylphenol were detected in water and tissue at concentrations that may cause adverse effects in fish. Interestingly, 29 CEC analytes were detected in effluent and fish tissue, but not in estuarine waters, indicating a high potential for bioaccumulation for these compounds. Although concentrations of most detected analytes were present at relatively low concentrations, our analysis revealed that overall CEC inputs to each estuary amount to several kilograms of these compounds per day. This study is unique because we report on CEC concentrations in estuarine waters and whole-body fish, which are both uncommon in the literature. A noteworthy finding was the preferential bioaccumulation of CECs in free-ranging juvenile Chinook salmon relative to staghorn sculpin, a benthic species with relatively high site fidelity.

Complex mixtures, complex responses: Assessing pharmaceutical mixtures using field and laboratory approaches

Pharmaceuticals are present in low concentrations (<100 ng/L) in most municipal wastewater effluents but may be elevated locally because of factors such as input from pharmaceutical formulation facilities. Using existing concentration data, the authors assessed pharmaceuticals in laboratory exposures of fathead minnows (Pimephales promelas) and added environmental complexity through effluent exposures. In the laboratory, larval and mature minnows were exposed to a simple opioid mixture (hydrocodone, methadone, and oxycodone), an opioid agonist (tramadol), a muscle relaxant (methocarbamol), a simple antidepressant mixture (fluoxetine, paroxetine, venlafaxine), a sleep aid (temazepam), or a complex mixture of all compounds. Larval minnow response to effluent exposure was not consistent. The 2010 exposures resulted in shorter exposed minnow larvae, whereas the larvae exposed in 2012 exhibited altered escape behavior. Mature minnows exhibited altered hepatosomatic indices, with the strongest effects in females and in mixture exposures. In addition, laboratory-exposed, mature male minnows exposed to all pharmaceuticals (except the selective serotonin reuptake inhibitor mixture) defended nest sites less rigorously than fish in the control group. Tramadol or antidepressant mixture exposure resulted in increased splenic T lymphocytes. Only male minnows exposed to whole effluent responded with increased plasma vitellogenin concentrations. Female minnows exposed to pharmaceuticals (except the opioid mixture) had larger livers, likely as a compensatory result of greater prominence of vacuoles in liver hepatocytes. The observed alteration of apical endpoints central to sustaining fish populations confirms that effluents containing waste streams from pharmaceutical formulation facilities can adversely impact fish populations but that the effects may not be temporally consistent. The present study highlights the importance of including diverse biological endpoints spanning levels of biological organization and life stages when assessing contaminant interactions.

Effects of an antidepressant mixture on the brain serotonin and predation behavior of hybrid striped bass

Antidepressants have been found in measurable concentrations in final treated wastewater effluent and receiving waters throughout the world. Studies have shown that these concentrations are typically not overtly toxic, but the psychotropic mode of action of these chemicals warrants examination of their behavioral effects. Exposure of hybrid striped bass to the antidepressants fluoxetine or venlafaxine alone has been shown to cause decreased brain serotonin levels and increased time to capture prey at concentrations typically 1 to 2 orders of magnitude higher than environmentally relevant concentrations. In the present study, equally effective doses of fluoxetine and venlafaxine were used to perform a mixture study, using a toxic unit approach to determine whether these antidepressants may act in an additive manner at lower concentrations. The results indicated that mixtures of these antidepressants caused decreased brain serotonin and increased time to capture prey at concentrations lower than reported in previous studies. Low concentration mixtures caused an additive effect on brain serotonin levels and time to capture prey, whereas higher concentrations were less than additive. The results were consistent with the dose addition concept, with higher concentration mixtures potentially saturating the effects on serotonin in the brain. Results from the present study indicate that antidepressants have the potential to be additive on the biochemical and individual scale, which necessitates more robust analysis of antidepressant mixtures and their potential to act together in low concentration scenarios.

The effects of antidepressants appear to be rapid and at environmentally relevant concentrations

The effects of antidepressants on wildlife are currently raising some concern because of an increased number of publications indicating biological effects at environmentally relevant concentrations (<100 ng/L). These results have been met with some scepticism because of the higher concentrations required to detect effects in some species and the perceived slowness to therapeutic effects recorded in humans and other vertebrates. Because their mode of action is thought to be by modulation of the neurotransmitters serotonin, dopamine, and norepinephrine, aquatic invertebrates that possess transporters and receptors sensitive to activation by these pharmaceuticals are potentially affected by them. The authors highlight studies on the effects of antidepressants, particularly on crustacean and molluskan groups, showing that they are susceptible to a wide variety of neuroendocrine disruptions at environmentally relevant concentrations. Interestingly, some effects observed in these species can be observed within minutes to hours of exposure. For example, exposure of amphipod crustaceans to several selective serotonin reuptake inhibitors can invoke changes in swimming behavior within hours. In mollusks, exposure to selective serotonin reuptake inhibitors can induce spawning in male and female mussels and foot detachment in snails within minutes of exposure. In the light of new studies indicating effects on the human brain from selective serotonin reuptake inhibitors using magnetic resonance imaging scans, the authors discuss possible reasons for the discrepancy in former results in relation to the read-across hypothesis, variation in biomarkers used, modes of uptake, phylogenetic distance, and the affinity to different targets and differential sensitivity to receptors.

Evaluating the extent of pharmaceuticals in surface waters of the United States using a National-scale Rivers and Streams Assessment survey

To assess the potential exposure of aquatic ecosystems to active pharmaceutical ingredients, the authors conducted a national-scale, probability-based statistical survey of the occurrence of these compounds in surface waters of the United States. The survey included 182 sampling sites and targeted rivers with close proximity to urban areas. The 46 analytes reported represent many classes of active pharmaceutical ingredients (APIs), including antibiotics, diuretics, antihypertensives, anticonvulsants, and antidepressants. Of the 46 analytes, 37 were detected in at least 1 sampling location. Sulfamethoxazole (an antibiotic) was the most frequently detected compound, being measured in 141 of the 182 surface waters surveyed at concentrations ranging up to 570 ng/L. Ten of the compounds were detected in 20% or more of the sampling sites. Weighted means of the analytical measurements are used with the statistical survey design and analysis to provide national estimates of the extent of contamination for these APIs in the nation's urban rivers. Published 2015 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US Government work and as such, is in the public domain in the United States of America.

Prioritizing human pharmaceuticals for ecological risks in the freshwater environment of Korea

Pharmaceutical residues are potential threats to aquatic ecosystems. Because more than 3000 active pharmaceutical ingredients (APIs) are in use, identifying high-priority pharmaceuticals is important for developing appropriate management options. Priority pharmaceuticals may vary by geographical region, because their occurrence levels can be influenced by demographic, societal, and regional characteristics. In the present study, the authors prioritized human pharmaceuticals of potential ecological risk in the Korean water environment, based on amount of use, biological activity, and regional hydrologic characteristics. For this purpose, the authors estimated the amounts of annual production of 695 human APIs in Korea. Then derived predicted environmental concentrations, using 2 approaches, to develop an initial candidate list of target pharmaceuticals. Major antineoplastic drugs and hormones were added in the initial candidate list regardless of their production amount because of their high biological activity potential. The predicted no effect concentrations were derived for those pharmaceuticals based on ecotoxicity information available in the literature or by model prediction. Priority lists of human pharmaceuticals were developed based on ecological risks and availability of relevant information. Those priority APIs identified include acetaminophen, clarithromycin, ciprofloxacin, ofloxacin, metformin, and norethisterone. Many of these pharmaceuticals have been neither adequately monitored nor assessed for risks in Korea. Further efforts are needed to improve these lists and to develop management decisions for these compounds in Korean water.

Pre-hatching fluoxetine-induced neurochemical, neurodevelopmental, and immunological changes in newly hatched cuttlefish

Embryonic and early postembryonic development of the cuttlefish Sepia officinalis (a cephalopod mollusk) occurs in coastal waters, an environment subject to considerable pressure from xenobiotic pollutants such as pharmaceutical residues. Given the role of serotonin in brain development and its interaction with neurodevelopmental functions, this study focused on fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI, antidepressant). The goal was to determine the effects of subchronic waterborne FLX exposure (1 and 10 μg L(-1)) during the last 15 days of embryonic development on neurochemical, neurodevelopmental, behavioral, and immunological endpoints at hatching. Our results showed for the first time that organic contaminants, such as FLX, could pass through the eggshell during embryonic development, leading to a substantial accumulation of this molecule in hatchlings. We also found that FLX embryonic exposure (1 and 10 μg L(-1)) (1) modulated dopaminergic but not serotonergic neurotransmission, (2) decreased cell proliferation in key brain structures for cognitive and visual processing, (3) did not induce a conspicuous change in camouflage quality, and (4) decreased lysozyme activity. In the long term, these alterations observed during a critical period of development may impair complex behaviors of the juvenile cuttlefish and thus lead to a decrease in their survival. Finally, we suggest a different mode of action by FLX between vertebrate and non-vertebrate species and raise questions regarding the vulnerability of early life stages of cuttlefish to the pharmaceutical contamination found in coastal waters.

Pharmaceuticals May Disrupt Natural Chemical Information Flows and Species Interactions in Aquatic Systems: Ideas and Perspectives on a Hidden Global Change

Pharmaceuticals consumption by humans and animals is increasing substantially, leading to unprecedented levels of these compounds in aquatic environments worldwide. Recent findings that concentrations reach levels that can directly have negative effects on organisms are important per se, but also sound an alarm for other potentially more pervasive effects that arise from the interconnected nature of ecological communities. Aquatic organisms use chemical cues to navigate numerous challenges, including the location of mates and food, and the avoidance of natural enemies. Low concentrations of pharmaceuticals can disrupt this "smellscape" of information leading to maladaptive responses. Furthermore, direct effects of pharmaceuticals on the traits and abundance of one species can cascade through a community, indirectly affecting other species. We review mechanisms by which pharmaceuticals in surface waters can disrupt natural chemical information flows and species interactions. Pharmaceuticals form a new class of chemical threats, which could have far-reaching implications for ecosystem functioning and conservation management.

Plant uptake of pharmaceutical and personal care products from recycled water and biosolids: a review

Reuse of treated wastewater for agricultural irrigation is growing in arid and semi-arid regions, while increasing amounts of biosolids are being applied to fields to improve agricultural outputs. These historically under-utilized resources contain "emerging contaminants", such as pharmaceutical and personal care products (PPCPs), which may enter agricultural soils and potentially contaminate food crops. In this review, we summarize recent research and provide a detailed overview of PPCPs in the soil-plant systems, including analytical methods for determination of PPCPs in plant tissues, fate of PPCPs in agricultural soils receiving treated wastewater irrigation or biosolids amendment, and plant uptake of PPCPs under laboratory and field conditions. Mechanisms of uptake and translocation of PPCPs and their metabolisms in plants are also reviewed. Field studies showed that the concentration levels of PPCPs in crops that were irrigated with treated wastewater or applied with biosolids were very low. Potential human exposure to PPCPs through dietary intake was discussed. Information gaps and questions for future research have been identified in this review.

Medicating the environment: assessing risks of pharmaceuticals to wildlife and ecosystems

Global pharmaceutical consumption is rising with the growing and ageing human population and more intensive food production. Recent studies have revealed pharmaceutical residues in a wide range of ecosystems and organisms. Environmental concentrations are often low, but pharmaceuticals typically are designed to have biological effects at low doses, acting on physiological systems that can be evolutionarily conserved across taxa. This Theme Issue introduces the latest research investigating the risks of environmentally relevant concentrations of pharmaceuticals to vertebrate wildlife. We take a holistic, global view of environmental exposure to pharmaceuticals encompassing terrestrial, freshwater and marine ecosystems in high- and low-income countries. Based on both field and laboratory data, the evidence for and relevance of changes to physiology and behaviour, in addition to mortality and reproductive effects, are examined in terms of the population- and community-level consequences of pharmaceutical exposure on wildlife. Studies on uptake, trophic transfer and indirect effects of pharmaceuticals acting via food webs are presented. Given the logistical and ethical complexities of research in this area, several papers focus on techniques for prioritizing which compounds are most likely to harm wildlife and how modelling approaches can make predictions about the bioavailability, metabolism and toxicity of pharmaceuticals in non-target species. This Theme Issue aims to help clarify the uncertainties, highlight opportunities and inform ongoing scientific and policy debates on the impacts of pharmaceuticals in the environment.

Leveraging existing data for prioritization of the ecological risks of human and veterinary pharmaceuticals to aquatic organisms

Medicinal innovation has led to the discovery and use of thousands of human and veterinary drugs. With this comes the potential for unintended effects on non-target organisms exposed to pharmaceuticals inevitably entering the environment. The impracticality of generating whole-organism chronic toxicity data representative of all species in the environment has necessitated prioritization of drugs for focused empirical testing as well as field monitoring. Current prioritization strategies typically emphasize likelihood for exposure (i.e. predicted/measured environmental concentrations), while incorporating only rather limited consideration of potential effects of the drug to non-target organisms. However, substantial mammalian pharmacokinetic and mechanism/mode of action (MOA) data are produced during drug development to understand drug target specificity and efficacy for intended consumers. An integrated prioritization strategy for assessing risks of human and veterinary drugs would leverage available pharmacokinetic and toxicokinetic data for evaluation of the potential for adverse effects to non-target organisms. In this reiview, we demonstrate the utility of read-across approaches to leverage mammalian absorption, distribution, metabolism and elimination data; analyse cross-species molecular target conservation and translate therapeutic MOA to an adverse outcome pathway(s) relevant to aquatic organisms as a means to inform prioritization of drugs for focused toxicity testing and environmental monitoring.

Prozac affects stickleback nest quality without altering androgen, spiggin or aggression levels during a 21-day breeding test

Pharmaceuticals are increasingly being used in human and veterinary medicine, and their presence in the aquatic environment may present a threat to non-target aquatic organisms. The selective serotonin reuptake inhibitor fluoxetine (Prozac) has been reported to affect diverse behaviours (feeding, aggression, and reproduction) and also the endocrine system (steroid biosynthesis pathway) in fish. To investigate these claims further, and in particular effects on androgen synthesis, male three-spined sticklebacks (Gasterosteus aculeatus) were exposed to fluoxetine at 0, 3.2, 10 and 32μg/L in a flow-through system for 21 days. Their sex was determined prior to exposure using a non-invasive method to collect DNA for determining the genetic sex, reported here for the first time. This was necessary as the exposure required males of a non-breeding status which had not developed secondary characteristics. Post exposure a number of biochemical (serotonin, steroid and spiggin levels) and apical (aggressive behaviour) endpoints were measured. No effects were detected on morphometric parameters, spiggin or androgen (11-ketotestosterone) levels. However, all fluoxetine-exposed male fish had higher cortisol levels in comparison to the control fish, although this effect only persisted throughout the whole exposure duration at the highest concentration (32μg/L). In addition, the ratio of 5-HIAA/5-HT (serotonin metabolite/serotonin) was significantly lower in the brains of males exposed to fluoxetine at all concentrations tested. Although we found no differences in the number of nests built by the males, the quality of the nests produced by the fluoxetine-exposed males was generally inferior consisting only of a basic, rudimentary structure. Males exposed to 32μg/L of fluoxetine displayed a delayed response to a simulated threat (rival male via own mirror image) and were less aggressive (number of bites and attacks) toward their mirror image, but these differences were not statistically significant. In summary, fluoxetine exposure resulted in reduced serotonergic activity in the male three-spined stickleback brain suggesting that the mechanism of action between humans and fish is at least partially conserved. Furthermore, this study provided additional evidence of cross-talk between the serotonergic and stress axes as demonstrated by the perturbations in cortisol levels. This potentially complex interaction at brain level may be responsible for the effects observed on nest quality, an endpoint with serious ecological consequences for this species. Finally, despite our hypothesis (an effect on steroid biosynthesis, based on limited literature evidence), we observed no effects of fluoxetine exposure (at the concentrations and duration employed) on male stickleback androgen levels.

Impacts of Pharmaceuticals on Terrestrial Wildlife

Essentially ubiquitous in our environment, residues of human and veterinary pharmaceuticals somewhat paradoxically represent an emerging and increasing risk to wild biota. Whilst in recent years a great deal of analytical effort has been expended to quantify the presence of many pharmaceutical contaminants, especially in freshwater systems, our real understanding of the risks posed to most clades of wildlife, aquatic and terrestrial alike, still lags behind. In particular, relevant field-based studies regarding possible chronic impacts in higher terrestrial wildlife (birds, mammals, reptiles, etc.) remain all too scarce. Yet, for example, over the past two decades Old World Gyps vultures on the Indian subcontinent have been virtually extirpated due to non-target exposure to a single synthetic pharmaceutical compound, diclofenac (a non-steroidal anti-inflammatory drug). Here, we highlight and discuss the myriad possible exposure routes to terrestrial wildlife, consider the analytical and monitoring approaches that are already in use or that could be used in future research, and reflect upon a selection of legislative approaches currently being applied to identified terrestrial impacts. Finally, with the ultimate aim of encouraging further applied ecotoxicology-based research in this emerging field, we highlight several priorities for future inquiry, with special emphasis on non-target effects in previously overlooked but potentially vulnerable or highly representative clades of wildlife exposed within environmentally relevant, real-world scenarios.

Ecotoxicology, Environmental Risk Assessment and Potential Impact on Human Health

This chapter examines potential risks posed by active pharmaceutical ingredients (APIs) present in the aquatic environment to humans and aquatic life. We begin by describing the mechanisms by which pharmaceuticals enter the vertebrate body, produce effects and leave the body. Then we describe theoretical and practical issues limiting the certainty which can be expected from risk estimates. This is followed by a description of particular considerations applicable to evaluation of human risks, along with a summary of methods and conclusions from some important studies examining those risks. A similar discussion of theoretical issues and selected data relevant for estimating risks to aquatic life is then presented. We finish by discussing potential contributions of antibiotics present in the environment to the development and spread of antibiotic resistance. We conclude that there are too few data to definitively address every concern, particularly risks to aquatic life and contributions to development of antibiotic resistance. On the other hand, available data suggest risks to humans are very low for all active pharmaceutical ingredients (APIs) and risks to aquatic life are very low for most APIs. Although aquatic risks cannot be as confidently ruled out for a few APIs, potential risks are probably limited to particularly contaminated regions in close vicinity to concentrated pollution sources, such as wastewater treatment plant outfalls.

Behavioral and biochemical responses in freshwater fish Carassius auratus exposed to sertraline

Sertraline is one of the most commonly prescribed selective serotonin reuptake inhibitors and is frequently detected in the aquatic environment. However, knowledge regarding relationships among molecular or biochemical endpoints involved in modes of action (MOAs) of sertraline and ecologically important behavioral responses of fish is insufficient. The present study aimed to investigate the bioconcentration and possible adverse outcomes pathways (AOPs) in crucian carp (Carassius auratus) exposed to various concentrations of sertraline (4.36, 21.3 and 116 μg L(-1)) for 7 d. Bioconcentration factor values were in the range of 19.5-626 in liver, 6.94-285 in brain, 4.01-146 in gill and 0.625-43.1 in muscle during the entire period of exposure. Liver superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities and brain acetylcholinesterase (AChE) activity were selected as biochemical endpoints associated with MOAs. Swimming activity, shoaling, feeding rate and food consumption were determined to assess behavioral responses. Fish plasma levels of sertraline exceeding human therapeutic doses were also predicted from external exposure concentrations. Significant enhancements in CAT, GPx, AChE and swimming activities and decreases in shoaling tendency, feeding rate and food consumption were observed when fish plasma levels exceeded human therapeutic thresholds. Shoaling, feeding rate and food consumption were correlated with the activities of SOD, CAT and GST. A significant positive correlation between swimming activity and AChE activity was also observed. As such, our study provides important AOPs linking biochemical responses with ultimate ecologically relevant behavioral endpoints.

Serotonin reuptake inhibitor citalopram inhibits GnRH synthesis and spermatogenesis in the male zebrafish

Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants for the treatment of depression. However, SSRIs cause sexual side effects such as anorgasmia, erectile dysfunction, and diminished libido that are thought to be mediated through the serotonin (5-hydroxytryptamine, 5-HT) system. In vertebrates, gonadotropin-releasing hormone (GnRH) neurons play an important role in the control of reproduction. To elucidate the neuroendocrine mechanisms of SSRI-induced reproductive failure, we examined the neuronal association between 5-HT and GnRH (GnRH2 and GnRH3) systems in the male zebrafish. Double-label immunofluorescence and confocal laser microscopy followed by three-dimensional construction analysis showed close associations between 5-HT fibers with GnRH3 fibers and preoptic-GnRH3 cell bodies, but there was no association with GnRH2 cell bodies and fibers. Quantitative real-time PCR showed that short-term treatment (2 wk) with low to medium doses (4 and 40 μg/L, respectively) of citalopram significantly decreased mRNA levels of gnrh3, gonadotropins (lhb and fshb) and 5-HT-related genes (tph2 and sert) in the male zebrafish. In addition, short-term citalopram treatment significantly decreased the fluorescence density of 5-HT and GnRH3 fibers compared with controls. Short-term treatment with low, medium, and high (100 μg/L) citalopram doses had no effects on the profiles of different stages of spermatogenesis, while long-term (1 mo) citalopram treatment with medium and high doses significantly inhibited the different stages of spermatogenesis. These results show morphological and functional associations between the 5-HT and the hypophysiotropic GnHR3 system, which involve SSRI-induced reproductive failures.

Toxicity screening of diclofenac, propranolol, sertraline and simvastatin using Danio rerio and Paracentrotus lividus embryo bioassays

Early life-stage bioassays have been used as an alternative to short-term adult toxicity tests since they are cost-effective. A single couple can produce hundreds or thousands of embryos and hence can be used as a simple high-throughput approach in toxicity studies. In the present study, zebrafish and sea urchin embryo bioassays were used to test the toxicity of four pharmaceuticals belonging to different therapeutic classes: diclofenac, propranolol, simvastatin and sertraline. Simvastatin was the most toxic tested compound for zebrafish embryo, followed by diclofenac. Sertraline was the most toxic drug to sea urchin embryos, inducing development abnormalities at the ng/L range. Overall, our results highlight the potential of sea urchin embryo bioassay as a promising and sensitive approach for the high-throughput methods to test the toxicity of new chemicals, including pharmaceuticals, and identify several drugs that should go through more detailed toxicity assays.

Reviewing the serotonin reuptake inhibitors (SSRIs) footprint in the aquatic biota: uptake, bioaccumulation and ecotoxicology

Selective serotonin re-uptake inhibitors (SSRIs) antidepressants are amongst the most prescribed pharmaceutical active substances throughout the world. Their presence, already described in different environmental compartments such as wastewaters, surface, ground and drinking waters, and sediments, and their remarkable effects on non-target organisms justify the growing concern about these emerging environmental pollutants. A comprehensive review of the literature data with focus on their footprint in the aquatic biota, namely their uptake, bioaccumulation and both acute and chronic ecotoxicology is presented. Long-term multigenerational exposure studies, at environmental relevant concentrations and in mixtures of related compounds, such as oestrogenic endocrine disruptors, continue to be sparse and are imperative to better know their environmental impact.

Transgenerational effects of two antidepressants (sertraline and venlafaxine) on Daphnia magna life history traits

The low levels of antidepressants detected in surface waters currently raise concern about their potential long-term risks to nontarget aquatic organisms. We investigated the transgenerational effects of sertraline, a selective serotonin reuptake inhibitor, and venlafaxine, a serotonin-norepinephrine reuptake inhibitor, on the life traits of Daphnia magna over two generations under environmentally realistic concentrations. We also studied the reversibility of the effect using recovery experiments. We assessed daphnid survival, growth, and reproduction over 21 days and evidenced detectable effects of the antidepressants. Sertraline increased the F0-daphnid fecundity whereas it decreased the offspring number of F1-daphnids. Transfer to clean medium caused negative effects on the offspring of daphnids exposed to 0.3 μg L(–1), but improved the fecundity of offspring of daphnids exposed to 100 μg L(–1). Venlafaxine exposure decreased the offspring number of F0-daphnids and resulted in drug tolerance in the F1 generation. Sertraline, unlike venlafaxine, may turn out to be a true environmental threat due to its accumulation in algae and the physiological weakness observed over generations. These effects across generations point out to the need to perform multigeneration tests to assess the environmental risk of pharmaceuticals in nontarget organisms.

Central actions of serotonin and fluoxetine on the QT interval of the electrocardiogram in trout

QT interval of the electrocardiogram (ECG) is a measure of the duration of the ventricular depolarization and repolarization. In humans, prolongation of the QT interval is a known clinical risk factor for the development of ventricular arrhythmias including ‘Torsades de Pointes’ and possible sudden cardiac death. After oral administration, fluoxetine (FLX), as well as other selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors can affect cardiac autonomic control, including the QT interval. However, the action of centrally administered FLX on the QT interval has never been explored. Consequently, using the unanesthetized trout as an animal model, we sought to compare the effects of intracerebroventricular (i.c.v.) injection of FLX (5, 15 or 25 µg) on the QT interval of the ECG with the effects observed following i.c.v. injection of 5-HT (0.05, 0.5 or 5 nmol). The QT interval was corrected for the R–R interval. The highest doses of centrally administered FLX and 5-HT induced a prolongation of the corrected QT (QTc) interval reaching a maximum value of 5–10 min after injection (+8% and +6% respectively, P < 0.05). The intra-arterial (i.a.) injections of 5-HT and FLX were without significant effect on the QTc. The i.a. injection of blockers of the autonomic nervous system indicated that the sympathetic nervous system modulated the QTc interval. In conclusion, our data demonstrate that for the first time in any animal species, cardiac electrophysiology is sensitive to central 5-HT and that FLX within the brain may disrupt the autonomic control of ventricular repolarization.

Casting a wider fish net on animal models in neuropsychiatric research

Neuropsychiatric disorders, such as schizophrenia, are associated with abnormal brain development. In this review, we discuss how studying dimensional components of these disorders, or endophenotypes, in a wider range of animal models will deepen our understanding of how interactions between biological and environmental factors alter the trajectory of neurodevelopment leading to aberrant behavior. In particular, we discuss some of the advantages of incorporating studies of brain and behavior using a range of teleost fish species into current neuropsychiatric research. From the perspective of comparative neurobiology, teleosts share a fundamental pattern of neurodevelopment and functional brain organization with other vertebrates, including humans. These shared features provide a basis for experimentally probing the mechanisms of disease-associated brain abnormalities. Moreover, incorporating information about how behaviors have been shaped by evolution will allow us to better understand the relevance of behavioral variation to determine their physiological underpinnings. We believe that exploiting the conservation in brain development across vertebrate species, and the rich diversity of fish behavior in lab and natural populations will lead to significant new insights and a holistic understanding of the neurobiological systems implicated in neuropsychiatric disorders.

Ecological effects of pharmaceuticals in aquatic systems--impacts through behavioural alterations

The study of animal behaviour is important for both ecology and ecotoxicology, yet research in these two fields is currently developing independently. Here, we synthesize the available knowledge on drug-induced behavioural alterations in fish, discuss potential ecological consequences and report results from an experiment in which we quantify both uptake and behavioural impact of a psychiatric drug on a predatory fish (Perca fluviatilis) and its invertebrate prey (Coenagrion hastulatum). We show that perch became more active while damselfly behaviour was unaffected, illustrating that behavioural effects of pharmaceuticals can differ between species. Furthermore, we demonstrate that prey consumption can be an important exposure route as on average 46% of the pharmaceutical in ingested prey accumulated in the predator. This suggests that investigations of exposure through bioconcentration, where trophic interactions and subsequent bioaccumulation of exposed individuals are ignored, underestimate exposure. Wildlife may therefore be exposed to higher levels of behaviourally altering pharmaceuticals than predictions based on commonly used exposure assays and pharmaceutical concentrations found in environmental monitoring programmes.

Aquatic toxicology of fluoxetine: understanding the knowns and the unknowns

Fluoxetine is one of the most prescribed psychotropic medications, and is an agent of increasing interest for environmental toxicology. Fish and other aquatic organisms are excellent models to study neuroactive small molecules like fluoxetine. However, prone to variance due to experimental factors, data obtained in these models need to be interpreted with caution, using proper experimental protocols, study designs, validated endpoints as well as well-established models and tests. Choosing the treatment protocol and dose range for fluoxetine and other serotonergic drugs is critical for obtaining valid test results and correct data interpretation. Here we discuss the value of aquatic models to study fluoxetine effects, based on prior high-quality research, and outline the directions of future translational studies in the field. We review fluoxetine-evoked phenotypes in acute vs. chronic protocols, discussing them in the contact of complex role of serotonin in behavioral regulation. We conclude that zebrafish and other aquatic models represent a useful in-vivo tool for fluoxetine pharmacology and (eco)toxicology research.

Treated wastewater irrigation: uptake of pharmaceutical and personal care products by common vegetables under field conditions

Global water shortage is placing an unprecedented pressure on water supplies. Treated wastewater is a valuable water resource, but its reuse for agricultural irrigation faces a roadblock: the public concern over the potential accumulation of contaminants of emerging concern (CECs) into human diet. In the present study, we measured the levels of 19 commonly occurring pharmaceutical and personal care products (PPCPs) in 8 vegetables irrigated with treated wastewater under field conditions. Tertiary treated wastewater without or with a fortification of each PPCP at 250 ng/L, was used to irrigate crops until harvest. Plant samples at premature and mature stages were collected. Analysis of edible tissues showed a detection frequency of 64% and 91% in all vegetables from the treated wastewater and fortified water treatments, respectively. The edible samples from the two treatments contained the same PPCPs, including caffeine, meprobamate, primidone, DEET, carbamazepine, dilantin, naproxen, and triclosan. The total concentrations of PPCPs detected in edible tissues from the treated wastewater and fortified irrigation treatments were in the range of 0.01-3.87 and 0.15-7.3 ng/g (dry weight), respectively. Annual exposure of PPCPs from the consumption of mature vegetables irrigated with the fortified water was estimated to be only 3.69 μg per capita. Results from the present study showed that the accumulation of PPCPs in vegetables irrigated with treated wastewater was likely limited under field conditions.

Effects of intracerebroventricular administered fluoxetine on cardio-ventilatory functions in rainbow trout (Oncorhynchus mykiss)

Fluoxetine (FLX) is a selective serotonin (5-HT) reuptake inhibitor present in the aquatic environment which is known to bioconcentrate in the brains of exposed fish. FLX acts as a disruptor of various neuroendocrine functions in the brain, but nothing is known about the possible consequence of FLX exposure on the cardio-ventilatory system in fish. Here we undertook to investigate the central actions of FLX on ventilatory and cardiovascular function in unanesthetized rainbow trout (Oncorhynchus mykiss). Intracerebroventricular (ICV) injection of FLX (dosed between 5 and 25 μg) resulted in a significantly elevated total ventilation (VTOT), with a maximum hyperventilation of +176% (at a dose of 25μg) compared with vehicle injected controls. This increase was due to an increase in ventilatory amplitude (VAMP: +126%) with minor effects on ventilatory frequency. The highest dose of FLX (25 μg) produced a significant increase in mean dorsal aortic blood pressure (PDA: +20%) without effects on heart rate (ƒH). In comparison, intra-arterial injections of FLX (500-2,500 μg) had no effect on ventilation but the highest doses increased both PDA and ƒH. The ICV and IA cardio-ventilatory effects of FLX were very similar to those previously observed following injections of 5-HT, indicating that FLX probably acts via stimulating endogenous 5-HT activity through inhibition of 5-HT transporter(s). Our results demonstrate for the first time in fish that FLX administered within the brain exerts potent stimulatory effects on ventilation and blood pressure increase. The doses of FLX given to fish in our study are higher than the brain concentrations of FLX in fish that result from acute exposure to FLX through the water. Nonetheless, our results indicate possible disrupting action of long term exposure to FLX discharged into the environment on central target sites sensitive to 5-HT involved in cardio-ventilatory control.

Environmental side effects of pharmaceutical cocktails: what we know and what we should know

Cocktails of pharmaceuticals are released in the environment after human consumption and due to the incomplete removal at the wastewater treatment plants. Pharmaceuticals are considered as contaminants of emerging concern and, a plethora of journal articles addressing their possible adverse effects have been published during the past 20 years. The emphasis during the early years of research within this field, was on the assessment of acute effects of pharmaceuticals applied singly, leading to results regarding their environmental risk, potentially not realistic or relevant to the actual environmental conditions. Only recently has the focus been shifted to chronic exposure and to the assessment of cocktail effects. To this end, this review provides an up-to-date compilation of 57 environmental and human toxicology studies published during 2000-2014 dealing with the adverse effects of pharmaceutical mixtures. The main challenges regarding the design of experiments and the analysis of the results regarding the effects of pharmaceutical mixtures to different biological systems are presented and discussed herein. The gaps of knowledge are critically reviewed highlighting specific future research needs and perspectives.

A one-year follow-up analysis of antidepressants in Portuguese wastewaters: occurrence and fate, seasonal influence, and risk assessment

The occurrence, fate, seasonal influence and environmental risk assessment of four selective serotonin re-uptake inhibitors (SSRIs) antidepressants, citalopram, fluoxetine, paroxetine and sertraline, were studied in 15 different wastewater treatment plants (WWTPs) across Portugal. Influent and effluent samples from four sampling campaigns, in 2013, were extracted through Oasis HLB cartridges, and quantified through liquid chromatography with tandem mass spectrometry (LC-MSn).Results showed that citalopram was the SSRI most frequently found, both in influents and in effluents, with mean mass loads ranging between 14.56 and 9.51 mg/day/1000 inhabitants, respectively. Fluoxetine and sertraline were only detected in influent samples, in lower mean mass loads (14.60 and 1.36 mg/day/1000 inhab., respectively), whereas paroxetine was found in influent and effluent samples (12.61 and 18.90 mg/day/1000 inhab., respectively). WWTPs were not capable of completely removing these pharmaceuticals; nonetheless, the mean removal efficiency was 82.24%. Removal efficiency was lower in winter (74.21%), summer (72.02%), and autumn (81.19%), when compared to spring (100%). Our results translate the variations in SSRI prescription and use between the five Portuguese regions in study. Influent contaminated samples were found in WWTPs from Lisbon, Alentejo, Center and North (28.25, 19.01, 16.55 and 6.98 mg/day/1000 inhab., respectively). In the Algarve region no contaminated samples were found. A seasonal pattern in the presence of SSRIs in influent wastewaters was observed. The SSRIs mass loads in influent wastewaters were higher in autumn, followed by spring, winter, and summer. Finally, the potential ecotoxicological risk posed by SSRIs to different trophic levels of aquatic organisms, exposed to the effluent wastewaters studied was evaluated by means of risk quotients (RQ). Citalopram and paroxetine, the only SSRIs found in these samples, presented RQ lower than 1. According to the results, algae appeared to be the most sensitive followed by fish and daphnids.

Effects of active pharmaceutical ingredients mixtures in mussel Mytilus galloprovincialis

Active pharmaceutical ingredients (APIs) are emergent environmental contaminants widely detected in surface waters as result of incomplete waste water treatment plant (WWTP) removal processes and improper disposal. The assessment of potential effects of APIs on non-target organisms is still scarce since besides presenting multiple chemical structures, properties and modes of action, these compounds occur as complex mixtures. This study comprises a 15-day exposure of mussels Mytilus galloprovincialis to mixtures (at environmentally relevant nominal concentrations) of non-steroidal inflammatory drugs ibuprofen (IBU) and diclofenac (DCF) (250 ng L(-1) each) and selective serotonin reuptake inhibitor (SSRI) fluoxetine (FLX) (75 ng L(-1)) (MIX 1) along with the addition of classical pro-oxidant copper (Cu) (5 μg L(-1)) (MIX 2). The goals included the assessment of oxidative stress, neurotoxic and endocrine effects on this sentinel species applying both a multibiomarker and gene expression (here and later gene expression is taken as synonym to gene transcription, although it is acknowledged that it is also affected by, e.g. translation, and mRNA and protein stability) analysis approaches. The results revealed a swifter antioxidant response in digestive glands than in gills induced by MIX 1, nevertheless the presence of Cu in MIX 2 promoted a higher lipid peroxidation (LPO) induction. Neither mixture altered acetylcholinesterase (AChE) activity, while both triggered the formation of vitellogenin-like proteins in females confirming the xenoestrogenic effect of mixtures. All these results varied with respect to those obtained in previous single exposure essays. Moreover, RT-PCR analysis revealed a catalase (CAT) and CYP4Y1 gene expression down- and upregulation, respectively, with no significant changes in mRNA levels of genes encoding superoxide dismutase (SOD) and glutathione-S-transferase (GST). Finally, this study highlights variable tissue and time-specific biomarker responses and gene expression alterations, which along with several interactions between each mixture component on each biomarker confirm the susceptibility of mussels to API mixtures.

The apparently very variable potency of the anti-depressant fluoxetine

The anti-depressant fluoxetine is widely present in the aquatic environment. Typical river concentrations are in the low ng/L range. Many ecotoxicity studies have assessed the effects of this pharmaceutical on a range of aquatic species. Some studies report that ng, or even pg, per litre concentrations cause effects, whereas other studies report that effects only occur when the water concentration is in the μg/L range. It seems unlikely that all reported effects will be repeatable. Many of the studies have considerable limitations. Currently it is impossible to ascertain what environmental concentrations of fluoxetine pose a risk to aquatic organisms. The key question can be answered only by high quality, reproducible research.

Reprint of: Effects of the antidepressant venlafaxine on fish brain serotonin and predation behavior

Antidepressants that enter receiving waters through final treated wastewater effluent have exhibited relatively low acute toxicity in traditional fish tests at currently measured concentrations. However, the psychotropic mode of action of these compounds warrants examination of the behavioral effects these chemicals may have on aquatic organisms. Previous research has demonstrated that exposure to the antidepressant fluoxetine causes decreased brain serotonin levels in fish and results in a decreased ability to capture prey. Another antidepressant, venlafaxine, has been found at low μg/L concentrations in final treated wastewater effluent. The objective of this study was to quantify the effects of venlafaxine on fish predation behavior and determine if this effect was correlated with changes in brain neurotransmitter concentrations. The predator prey bioassay used hybrid striped bass (Morone saxatilis x Morone chrysops) as the predator and fathead minnows (Pimephales promelas) as prey. Bass were exposed to venlafaxine (0-500 μg/L) for a period of 6 days and then allowed to recover for 6 days. During both exposure and recovery, bass were fed four minnows every third day. The time to capture the minnows was quantified and compared among treatments to determine if there was an effect on predation behavior. Brain tissue was analyzed for serotonin, norepinephrine, and dopamine, to determine the relationship between exposure concentration, brain monoamine levels, and predation behavior. Results indicated that venlafaxine exposures increased time to capture prey 1 and 2 by day 6 for the 250 and 500 μg/L treatments. Time to capture prey 3 was increased for all venlafaxine treatments by day 6. Venlafaxine caused a statistically significant decrease in brain serotonin concentrations that initially decreased in a dose dependent manner before reaching a steady state by the end of exposures for all treatments. No significant, dose-dependent changes in dopamine or norepinephrine were seen. Brain serotonin alone did not adequately explain behavioral results. Serotonin response in other tissues as well as peripheral effects may have accounted for additional behavioral responses after brain serotonin reached a depressed steady state.

Effects of triclocarban, N,N-diethyl-meta-toluamide, and a mixture of pharmaceuticals and personal care products on fathead minnows (Pimephales promelas)

Pharmaceuticals and personal care products (PPCPs) have been detected widely in aquatic ecosystems, but little is known about their mechanisms of toxicity. We exposed adult fathead minnows (Pimephales promelas) for 48 h to triclocarban (1.4 µg/L), N,N-diethyl-meta-toluamide (DEET; 0.6 µg/L), or a mixture of PPCPs consisting of atenolol (1.5 µg/L), caffeine (0.25 µg/L), diphenhydramine (0.1 µg/L), gemfibrozil (1.5 µg/L), ibuprofen (0.4 µg/L), naproxen (1.6 µg/L), triclosan (2.3 µg/L), progesterone (0.2 µg/L), triclocarban (1.4 µg/L), and DEET (0.6 µg/L). Quantitative real-time polymerase chain reaction revealed an upregulation in vitellogenin (vtg) in livers of females and males exposed to triclocarban. Also, an upregulation of hepatic lipoprotein lipase (lpl) and a downregulation of androgen receptor (ar) and steroidogenic acute regulatory protein (star) were observed in testes. The group treated with DEET only showed a significant decrease in ar in females. In contrast, the PPCP mixture downregulated vtg in females and males and expression of estrogen receptor alpha (erα), star, and thyroid hormone receptor alpha 1 (thra1) in testes. The authors' results show that the molecular estrogenic effects of triclocarban are eliminated (males) or reversed (females) when dosed in conjunction with several other PPCP, once again demonstrating that results from single exposures could be vastly different from those observed with mixtures. Environ Toxicol Chem 2014;33:910-919. © 2013 SETAC.

Effects of the antidepressant venlafaxine on fish brain serotonin and predation behavior

Antidepressants that enter receiving waters through final treated wastewater effluent have exhibited relatively low acute toxicity in traditional fish tests at currently measured concentrations. However, the psychotropic mode of action of these compounds warrants examination of the behavioral effects these chemicals may have on aquatic organisms. Previous research has demonstrated that exposure to the antidepressant fluoxetine causes decreased brain serotonin levels in fish and results in a decreased ability to capture prey. Another antidepressant, venlafaxine, has been found at low μg/L concentrations in final treated wastewater effluent. The objective of this study was to quantify the effects of venlafaxine on fish predation behavior and determine if this effect was correlated with changes in brain neurotransmitter concentrations. The predator prey bioassay used hybrid striped bass (Morone saxatilis x Morone chrysops) as the predator and fathead minnows (Pimephales promelas) as prey. Bass were exposed to venlafaxine (0-500 μg/L) for a period of 6 days and then allowed to recover for 6 days. During both exposure and recovery, bass were fed four minnows every third day. The time to capture the minnows was quantified and compared among treatments to determine if there was an effect on predation behavior. Brain tissue was analyzed for serotonin, norepinephrine, and dopamine, to determine the relationship between exposure concentration, brain monoamine levels, and predation behavior. Results indicated that venlafaxine exposures increased time to capture prey 1 and 2 by day 6 for the 250 and 500 μg/L treatments. Time to capture prey 3 was increased for all venlafaxine treatments by day 6. Venlafaxine caused a statistically significant decrease in brain serotonin concentrations that initially decreased in a dose dependent manner before reaching a steady state by the end of exposures for all treatments. No significant, dose-dependent changes in dopamine or norepinephrine were seen. Brain serotonin alone did not adequately explain behavioral results. Serotonin response in other tissues as well as peripheral effects may have accounted for additional behavioral responses after brain serotonin reached a depressed steady state.

Exposures to a selective serotonin reuptake inhibitor (SSRI), sertraline hydrochloride, over multiple generations: changes in life history traits in Ceriodaphnia dubia

Selective serotonin reuptake inhibitors (SSRIs) have been reported to range from low parts per trillion to parts per billion levels in surface waters, wastewater effluents, and sediments. These low levels have led to concern for their potential long-term risks to the survival, growth, and reproduction of aquatic organisms. We investigated the acute and chronic effects of sertraline on the life history traits of Ceriodaphnia dubia over the course of three generations under environmentally realistic concentrations. Acute toxicity of sertraline in C. dubia offspring resulted in a 48h median effective concentration of 126µgL(-1). Under chronic exposure, the lowest concentration to affect fecundity and growth was at 53.4µgL(-1) in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8µgL(-1). The median effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2µgL(-1), respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to sertraline leads to effects that occur at concentrations only an order of magnitude higher than predicted environmental concentrations. However, this study also demonstrates that multigenerational effects should be considered in chronic exposure studies because standard toxicity tests do not account for increases in sensitivity in successive generations to toxicants.

Fish biomarkers for regulatory identification of endocrine disrupting chemicals

Demonstrating chemical-induced adverse effects, endocrine mechanisms/modes of action (MOAs) and their causal link is needed for regulatory identification of endocrine disrupting chemicals (EDCs). This paper addresses critical issues over MOAs and their causal link to changes in endpoints. Vitellogenin (VTG), secondary sex characteristics (SSC), and sex ratio (also an apical endpoint) are indicative of chemicals interfering with EAS (estrogen, androgen and steroidogenesis) pathways. These biomarkers, however, can be changed by non-EAS chemicals, systemic toxicity and the stress response. Examples are shown that proving causal link between MOAs and changes in endpoints may be difficult for regulatory identification of EDCs. The paper concludes that both in vitro and in vivo data are needed to define MOAs for regulatory identification of EDCs. Further development of guidance documents for data interpretation and for defining the level of evidence is needed for regulatory identification of EDCs.

Enantioselective quantification of fluoxetine and norfluoxetine by HPLC in wastewater effluents

Microbial degradation is the most important process to remove organic pollutants in Waste Water Treatment Plants. Regarding chiral compounds this process is normally enantioselective and needs the suitable analytical methodology to follow the removal of both enantiomers in an accurate way. Thus, this paper describes the development and validation of an enantioselective High Performance Liquid Chromatography with Fluorescence Detection (HPLC-FD) method for simultaneous analysis of fluoxetine (FLX) and norfluoxetine (NFLX) in wastewater effluents. Briefly, this method preconcentrated a small volume of wastewater samples (50 mL) on 500 mg Oasis MCX cartridges and used HPLC-FD with a vancomycin-based chiral stationary phase under reversed mode for analyses. The optimized mobile phase was EtOH/aqueous ammonium acetate buffer (92.5/7.5, v/v) at pH 6.8. The effect of EtOH percentage, buffer concentration, pH, column oven temperature and flow rate on chromatographic parameters was systematically investigated. The developed method was validated within the wastewater effluent used in microcosms laboratory assays. Linearity (R(2)>0.99), selectivity and sensitivity were achieved in the range of 4.0-60 ng mL(-1) for enantiomers of FLX and 2.0-30 ng mL(-1) for enantiomers of NFLX. The limits of detection were between 0.8 and 2.0 ng mL(-1) and the limits of quantification were between 2.0 and 4.0 ng mL(-1) for both enantiomers of FLX and the enantiomers of its demethylated metabolite NFLX. The validated method was successfully applied and proved to be robust to follow the degradation of both enantiomers of FLX in wastewater samples, during 46 days.