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

Does wastewater treatment plant upgrading with activated carbon result in an improvement of fish health?

In the present study, the efficiency of a wastewater treatment plant (WWTP) upgraded with a powdered activated carbon unit for the reduction of micropollutants and the related advantages for fish health have been analyzed by means of different biomarkers, i.e. histopathological investigations, analyses of glycogen content and stress proteins, as well as by chemical analyses in different matrices. Comparative analyses were conducted prior and subsequent to the installation of the additional purification unit. Chemical analyses revealed a significant reduction of several pharmaceuticals, including diclofenac, carbamazepine and metoprolol, in samples of effluent and surface water downstream of the WWTP after its upgrade. In addition, diminished concentrations of diclofenac and PFOS were detected in tissues of analyzed fish. Histopathological investigations of fish liver, gills, and kidney revealed improved tissue integrity in fish after improved wastewater treatment. In parallel, biochemical measurements of glycogen revealed increased energy resources in fish liver and, furthermore, hsp70 levels in livers of exposed rainbow trout and in kidneys of exposed brown trout were lower after than before the WWTP upgrade. In summary, additional treatment with powdered activated carbon led to a reduction of potentially hazardous chemicals in the effluent and the adjacent river and, consequently, to an improvement of fish health in the receiving water course.

Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review

In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems.

Effects of selected tricyclic antidepressants on early-life stages of common carp (Cyprinus carpio)

Despite the fact that pharmaceuticals occur in surface water in low concentrations, they can still have adverse effect on aquatic biota, because these substances are designed to have a specific mode of action even at low concentrations. To our knowledge, only little is known about the long-term effect of tricyclic antidepressant residues on non-target animals, especially fish. Hence, the aim of this study was to assess the effect of subchronic exposure to selected tricyclic antidepressants - namely, amitriptyline, nortriptyline, and clomipramine and their mixture - on early-life stages of common carp (Cyprinus carpio). Two embryo-larval toxicity tests with common carp were performed, each taking 30 days. For the experiment, three tricyclic antidepressants as well as their mixtures were tested at three different concentrations - 10, 100 and 500 μg/L. Hatching and mortality were recorded twice a day. In addition, samples were taken at regular intervals in order to record developmental stage, morphometric and condition characteristics and morphological anomalies. At the end of the test, additional samples were taken for histopathological examination and also for the determination of antioxidant and biotransformation enzyme activity and lipid peroxidation and protein carbonylation. Long-term exposure resulted in a significant increase in mortality, developmental retardation, morphological anomalies, and pathological changes in brain, heart, and cranial and caudal kidney. In addition, changes in antioxidant enzyme activity as well as increased lipid peroxidation were observed, even at the lowest tested concentrations. Hence, environmentally relevant concentrations of TCAs have the potential to cause harmful effects on early-life stages of fish.

Prioritization of pharmaceuticals based on risks to aquatic environments in Kazakhstan

Over the last 20 years, there has been increasing interest in the occurrence, fate, effects, and risk of pharmaceuticals in the natural environment. However, we still have only limited or no data on ecotoxicological risks of many of the active pharmaceutical ingredients (APIs) currently in use. This is partly due to the fact that the environmental assessment of an API is an expensive, time-consuming, and complicated process. Prioritization methodologies, which aim to identify APIs of most concern in a particular situation, could therefore be invaluable in focusing experimental work on APIs that really matter. The majority of approaches for prioritizing APIs require annual pharmaceutical usage data. These methods cannot therefore be applied to countries, such as Kazakhstan, that have very limited data on API usage. The present paper therefore offers an approach for prioritizing APIs in surface waters in information-poor regions such as Kazakhstan. Initially data were collected on the number of products and active ingredients for different therapeutic classes in use in Kazakhstan and on the typical doses. These data were then used alongside simple exposure modeling approaches to estimate exposure indices for active ingredients (about 240 APIs) in surface waters in the country. Ecotoxicological effects data were obtained from the literature or predicted. Risk quotients were then calculated for each pharmaceutical based on the exposure and the substances were ranked in order of risk quotient. Highest exposure indices were obtained for benzylpenicillin, metronidazole, sulbactam, ceftriaxone, and sulfamethoxazole. The highest risk was estimated for amoxicillin, clarithromycin, azithromycin, ketoconazole, and benzylpenicillin. In the future, the approach could be employed in other regions where usage information is limited. Integr Environ Assess Manag 2017;13:832-839. © 2017 SETAC.

Significance of metabolites in the environmental risk assessment of pharmaceuticals consumed by human

The purpose of this study is to demonstrate the significance of metabolites to the ERA of human pharmaceuticals. The predicted exposure concentrations (PECs) in surface water were estimated for a total of 24 selected active pharmaceutical ingredients (APIs) and their metabolites using a life cycle based emission estimation model combined with a multimedia fate model with Monte-Carlo calculations. With the eco-toxicity data, the hazard quotients (HQs) of the metabolites were compared with those of individual parents alone. The results showed that PEC or toxicity or both of the metabolites was predicted to be higher than that of their parent APIs, which resulted in a total of 18 metabolites (from 12 parents) that have greater HQs than their parents. This result clearly demonstrated that some metabolites may potentially pose greater risk than their parent APIs in the water environment. Therefore, significance of metabolites should be carefully evaluated for monitoring strategy, priority setting, and scoping of the environmental risk assessment of APIs. The method used in the present work may serve as a pragmatic approach for the purpose of preliminary screening or priority setting of environmental risk posed by both APIs and their metabolites.

Paracetamol causes endocrine disruption and hepatotoxicity in male fish Rhamdia quelen after subchronic exposure

Paracetamol is one of the most widely sold non-prescription drugs. This study aimed to evaluate the effects of the paracetamol on reproductive, biochemical, genetic, histopathological and hematogical biomarkers by waterborne exposure. Male fish of Rhamdia quelen were exposed to environmental concentrations of paracetamol (0, 0.25, 2.5μg/L) in a semi-static bioassay for 21days. Hemoglobin and hematocrit were reduced upon exposure to 0.25μg/L of paracetamol. Leukocytes and thrombocytes increased after paracetamol exposure. Paracetamol reduced testosterone levels in all exposed groups and increased estradiol levels at higher concentration. Serotonin and dopamine levels increased at exposure to 0.25μg/L. Paracetamol also caused protein carbonyls and increased SOD activity in fish exposed to 2.5μg/L and in addition led to an inhibition of EROD and GST activities in both concentrations. Hepatic genotoxicity occurred at the 0.25μg/L concentration. Hepatic tissues of exposed fish showed mild blood congestion and leucocytes infiltration. The results showed that paracetamol disrupted the hypothalamic-pituitary-gonadal axis, changed hematological parameters and caused hepatotoxicity in Rhamdia quelen. The findings suggest that this drug merits attention relative to its potential endocrine disrupter effect and hepatotoxicity, even at concentrations found in the aquatic environment.

Histological alterations in gills and liver of rainbow trout (Oncorhynchus mykiss) after exposure to the antibiotic oxytetracycline

The aim of this study was to investigate the histopathological effects of oxytetracycline (OTC) on the gill and liver tissues of rainbow trouts (Oncorhynchus mykiss) following acute (96h: 0.005-50mg/L) and chronic (28days: 0.3125-5μg/L) exposures. Results suggest the existence of a cause-and-effect relationship between the exposure to OTC and tissue damage. Most predominant disorders observed in gills were progressive (e.g. hypertrophy of mucous cells and hyperplasia of epithelial cells) in acute exposure and regressive (e.g. lamellar fusion, epithelial lifting of lamellae and some changes in tissue architecture) in chronic exposure. However, only the acute exposure was responsible for a significant increase of the total gill pathological index. PAGE index, reflecting the extent of gill tissue available for gas exchanges in fish, remained unchanged for both exposures. In liver, circulatory (e.g. hemorrhage and increase of sinusoidal space), regressive (e.g. pyknotic nucleus, vacuolization and hepatocellular degenerations) and progressive (e.g. hypertrophy of hepatocytes) changes were observed, but just after acute exposure. After chronic exposure, only inflammatory changes (e.g. leucocytes infiltration) were observed. Following both exposures, a significant increase of the total liver pathological index was recorded. Despite the increase of the histological damage in individuals exposed to OTC, lesions observed were of minimal or moderate pathological importance, non-specific and reversible. The data gathered following acute and chronic exposures also suggest the onset of adaptive mechanisms of fish, namely for longer exposure periods. Furthermore the observed histological alterations appear to be result of several physio-metabolic disorders consequence of the biochemical and molecular modes of action of OTC.

The fate of pharmaceuticals and personal care products (PPCPs), endocrine disrupting contaminants (EDCs), metabolites and illicit drugs in a WWTW and environmental waters

A large number of emerging contaminants (ECs) are known to persist in surface waters, and create pressure on wastewater treatment works (WWTW) for their effective removal. Although a large database for the levels of these pollutants in water systems exist globally, there is still a lack in the correlation of the levels of these pollutants with possible long-term adverse health effects in wildlife and humans, such as endocrine disruption. The current study detected a total of 55 ECs in WWTW influent surface water, 41 ECs in effluent, and 40 ECs in environmental waters located upstream and downstream of the plant. A list of ECs persisted through the WWTW process, with 28% of all detected ECs removed by less than 50%, and 18% of all ECs were removed by less than 25%. Negative mass balances of some pharmaceuticals and metabolites were observed within the WWTW, suggesting possible back-transformation of ECs during wastewater treatment. Three parental illicit drug compounds were detected within the influent of the WWTW, with concentrations ranging between 27.6 and 147.0 ng L^-1 for cocaine, 35.6-120.6 ng L^-1 for mephedrone, and 270.9-450.2 ng L^-1 for methamphetamine. The related environmental risks are also discussed for some ECs, with particular reference to their ability to disrupt endocrine systems. The current study propose the potential of the pharmaceuticals carbamazepine, naproxen, diclofenac and ibuprofen to be regarded as priority ECs for environmental monitoring due to their regular detection and persistence in environmental waters and their possible contribution towards adverse health effects in humans and wildlife.

HSP72 is an early biomarker to detect cisplatin and acetaminophen nephrotoxicity

OBJECTIVE

To evaluate whether the urinary HSP72 levels (uHSP72) are a useful biomarker for early diagnosis of acute kidney injury (AKI) induced by two widely used drugs: cisplatin and acetaminophen.

MATERIALS AND METHODS

To analyze the time-course of nephrotoxic injury and uHSP72 levels, male Wistar rats were administered a single high dose of cisplatin (7 mg/kg) or acetaminophen (750 mg/kg) and were assessed at 6, 12, 24, 48, 72, 96 and 120 h.

RESULTS

AKI induced by cisplatin was characterized by tubular injury that started at 6 h and was enhanced after 48 h. Plasma creatinine was increased only after 72 h. In contrast, uHSP72 levels were augmented after 6 h and were enhanced after 48 h of cisplatin administration, which was consistent with the tubular injury. In acetaminophen-induced AKI, the tubular lesions were less severe and predominantly characterized by tubular cell detachment. Interestingly, uHSP72 levels were increased after 6 h of acetaminophen injection and remained elevated at the following time points, reflecting the tubular injury, even in the absence of major functional changes.

CONCLUSIONS

In two models of renal injury induced by nephrotoxic drugs, we showed that uHSP72 could be used as an early biomarker to detect subtle to severe tubular injury.

A multi-omic approach to elucidate low-dose effects of xenobiotics in zebrafish (Danio rerio) larvae

Regulatory-approved toxicity assays such as the OECD Fish Embryo Toxicity Assay (TG236) allow correlation of chemical exposure to adverse morphological phenotypes. However, these assays are ineffective in assessing sub-lethal (i.e. low-dose) effects, or differentiating between similar phenotypes induced by different chemicals. Inclusion of multi-omic analyses in studies investigating xenobiotic action provides improved characterization of biological response, thereby enhancing prediction of toxicological outcomes in whole animals in the absence of morphological effects. In the current study, we assessed perturbations in both the metabolome and transcriptome of zebrafish (Danio rerio; ZF) larvae exposed from 96 to 120h post fertilization to environmental concentrations of acetaminophen (APAP), diphenhydramine (DH), carbamazepine (CBZ), and fluoxetine (FLX); common pharmaceuticals with known mechanisms of action. Multi-omic responses were evaluated independently and integrated to identify molecular interactions and biological relevance of the responses. Results indicated chemical- and dose-specific changes suggesting differences in the time scale of transcript abundance and metabolite production. Increased impact on the metabolome relative to the transcriptome in FLX-treated animals suggests a stronger post-translational effect of the treatment. In contrast, the transcriptome showed higher sensitivity to perturbation in DH-exposed animals. Integration of 'omic' responses using multivariate approaches provided additional insights not obtained by independent 'omic' analyses and demonstrated that the most distinct overall response profiles were induced following low-dose exposure for all 4 pharmaceuticals. Importantly, changes in transcript abundance corroborated with predictions from metabolomic enrichment analyses and the identified perturbed biological pathways aligned with known xenobiotic mechanisms of action. This work demonstrates that a multi-omic toxicological approach, coupled with a sensitive animal model such as ZF larvae, can help characterize the toxicological relevance of acute low-dose chemical exposures.

Hidden drivers of low-dose pharmaceutical pollutant mixtures revealed by the novel GSA-QHTS screening method

The ecological impacts of emerging pollutants such as pharmaceuticals are not well understood. The lack of experimental approaches for the identification of pollutant effects in realistic settings (that is, low doses, complex mixtures, and variable environmental conditions) supports the widespread perception that these effects are often unpredictable. To address this, we developed a novel screening method (GSA-QHTS) that couples the computational power of global sensitivity analysis (GSA) with the experimental efficiency of quantitative high-throughput screening (QHTS). We present a case study where GSA-QHTS allowed for the identification of the main pharmaceutical pollutants (and their interactions), driving biological effects of low-dose complex mixtures at the microbial population level. The QHTS experiments involved the integrated analysis of nearly 2700 observations from an array of 180 unique low-dose mixtures, representing the most complex and data-rich experimental mixture effect assessment of main pharmaceutical pollutants to date. An ecological scaling-up experiment confirmed that this subset of pollutants also affects typical freshwater microbial community assemblages. Contrary to our expectations and challenging established scientific opinion, the bioactivity of the mixtures was not predicted by the null mixture models, and the main drivers that were identified by GSA-QHTS were overlooked by the current effect assessment scheme. Our results suggest that current chemical effect assessment methods overlook a substantial number of ecologically dangerous chemical pollutants and introduce a new operational framework for their systematic identification.

Assessment of the effects of the carbamazepine on the endogenous endocrine system of Daphnia magna

In the present study, the endocrine activity of the antiepileptic pharmaceutical carbamazepine (CBZ) in the crustacean Daphnia magna was assessed. To assess the hormonal activity of the drug, we exposed maternal daphnids and embryos to environmental relevant concentrations of CBZ (ranging from 10 to 200 μg/L) and to mixtures of CBZ with fenoxycarb (FEN; 1 μg/L). Chronic exposure to CBZ significantly decreased the reproductive output and the number of molts of D. magna at 200 μg/L. This compound induced the production of male offspring (12 ± 1.7 %), in a non-concentration-dependent manner, acting as a weak juvenile hormone analog. Results showed that this substance, at tested concentrations, did not antagonize the juvenoid action of FEN. Further, CBZ has shown to be toxic to daphnid embryos through maternal exposure interfering with their normal gastrulation and organogenesis stages but not producing direct embryo toxicity. These findings suggest that CBZ could act as an endocrine disruptor in D. magna as it decreases the reproductive output, interferes with sex determination, and causes development abnormality in offspring. Therefore, CBZ could directly affect the population sustainability.

Zebrafish: A Versatile Animal Model for Fertility Research

The utilization of zebrafish in biomedical research is very common in the research world nowadays. Today, it has emerged as a favored vertebrate organism for the research in science of reproduction. There is a significant growth in amount numbers of scientific literature pertaining to research discoveries in reproductive sciences in zebrafish. It has implied the importance of zebrafish in this particular field of research. In essence, the current available literature has covered from the very specific brain region or neurons of zebrafish, which are responsible for reproductive regulation, until the gonadal level of the animal. The discoveries and findings have proven that this small animal is sharing a very close/similar reproductive system with mammals. More interestingly, the behavioral characteristics and along with the establishment of animal courtship behavior categorization in zebrafish have laid an even stronger foundation and firmer reason on the suitability of zebrafish utilization in research of reproductive sciences. In view of the immense importance of this small animal for the development of reproductive sciences, this review aimed at compiling and describing the proximate close similarity of reproductive regulation on zebrafish and human along with factors contributing to the infertility, showing its versatility and its potential usage for fertility research.

Effects of carbamazepine and two of its metabolites on the non-biting midge Chironomus riparius in a sediment full life cycle toxicity test

The antiepileptic drug carbamazepine (CBZ) and its main metabolites carbamazepine-10,11-epoxide (EP-CBZ) and 10,11-dihydro-10,11-dihydroxy-carbamazepine (DiOH-CBZ) were chosen as test substances to assess chronic toxicity on the non-biting midge Chironomus riparius. All the three substances were tested in a 40-day sediment full life cycle test (according to OECD 233) in which mortality, emergence, fertility, and clutch size were evaluated. In addition, these parameters were considered to calculate the population growth rate which represents an integrated measure to assess population relevant effects. With an LC50 of 0.20 mg/kg (time-weighted mean), the metabolite EP-CBZ was significantly more toxic than the parent substance CBZ (LC50: 1.1 mg/kg). Especially mortality, emergence, and fertility showed to be sensitive parameters under the exposure to CBZ and EP-CBZ. By using classical molecular dynamics (MD) simulations, the binding of CBZ to the ecdysone receptor was investigated as one possible mode of action (MoA) but appeared to be unlikely. The second metabolite DiOH-CBZ did not cause any effects within the tested concentration rage (0.17-1.2 mg/kg). Even though CBZ was less toxic compared to EP-CBZ, CBZ is found in the environment at much higher concentrations and therefore causes a higher potential risk for sediment dwelling organisms compared to its metabolites. Nevertheless, the current study illustrates the importance of including commonly found metabolites into the risk assessment of parent substances.

Zebrafish as a possible bioindicator of organic pollutants in drinking waters with effects on reproduction: are effects cumulative or reversible?

Organic pollutants are present in drinking waters due to inefficient detection and removal treatments. For this reason, zebrafish is proposed as a complementary indicator in conventional potabilization treatments. Based on the most sensitive parameters detected in our previous work, in this study we attempted to examine the possible cumulative effect between generations of environmental pollutants likely present in drinking waters, when specimens were cultured in the same water and/or the possible reversibility of these effects when cultured in control water. To this end, embryos with the chorion intact were cultured in three drinking waters from different sources and in one control water for up to 5 months in 20 l glass tanks. Four replicates were performed in all water groups. Results in water group C (tap water from a city also located in a region with intensive agricultural activity, but from the hydrological basin of the river Xúquer) revealed a non-reversible effect on fertility rate. Also in water C there was an alteration of sex ratio towards females, although in this case the alteration was reversible. A transgenerational alteration in the germ-line via an epigenetic mechanism from the previous generation is proposed as the most plausible explanation of this effect.

Derivation of water quality standards for carbamazepine, metoprolol, and metformin and comparison with monitoring data

Environmental quality standards (EQSs) for 3 pharmaceuticals in surface water were derived: carbamazepine (epilepsy), metoprolol (heart failure), and metformin (diabetes). In recent years, these pharmaceuticals have been detected frequently in Dutch surface waters. The proposed standards are based on ecotoxicity data from national and European authorization dossiers and additional information obtained from open literature. The methods used are in accordance with the methodology of the Water Framework Directive and national frameworks for risk limit derivation. Only the exposure route regarding direct ecotoxic effects on ecosystems could be taken into account for deriving EQSs. The exposure route of secondary poisoning of fish-eating animals was not triggered, and not enough data were available or accessible to derive an EQS for the exposure of humans due to consumption of fish. Monitoring data for surface waters worldwide show that the proposed quality standards for carbamazepine may be exceeded. It could be expected that when carbamazepine use increases or effluents are diluted less during dry seasons, standards will be exceeded more often.

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.

Pharmaceuticals and personal care products (PPCPs) in Australia's largest inland sewage treatment plant, and its contribution to a major Australian river during high and low flow

Reports of pharmaceuticals in STPs and aquatic systems in the northern hemisphere have surged over the last decade. However, the Australian evidence base is relatively limited, and information on the role of seasonal dilution in attenuation of micropollutants is also scarce. We investigated the removal of 11 PPCPs during sewage treatment in Australia's largest inland STP, and concentrations in the effluent-receiving environment under 2 dilution scenarios. Five treatment stages were sampled, as well as upstream and downstream of the effluent outfall in the Lower Molonglo/Upper Murrumbidgee Catchment, which is dominated by effluent flow during dry periods. Compounds of interest include carbamazepine (CBZ), venlafaxine (VEN), sertraline (SER), fluoxetine (FLX), atenolol (ATL), sotalol (SOT), metoprolol (MET) propranolol (PRL), chlorpheniramine (CHP), diphenhydramine (DPH), and triclosan (TCS). Removal of most pharmaceuticals in the STP was incomplete, although the degree of removal was highly variable for compounds in the same therapeutic class, and for the same compounds in different seasons. Removal efficiency was highest for TCS and lowest for VEN (effluent concentrations 5-7 times higher than influent). Influent mass loads and removal efficiencies of cardiovascular medicines varied considerably. Effluent loads were highest for CBZ, VEN and SOT in both seasons (up to 64 g/day). The dilution conditions were clearly reflected in the 'zone of impact' of PPCPs in the catchment. This study confirms that risk assessment models for PPCPs must account for seasonality of influent loads and removal efficiency of STPs, and site validation is critical for predictive capability. Seasonal dilution can play an important role in ameliorating potentially adverse effects related to mixtures of PPCPs in effluent-impacted systems.

Pharmaceuticals and personal care products in waters: occurrence, toxicity, and risk

Pharmaceuticals and personal care products (PPCP) are compounds with special physical and chemical properties that address the care of animal and human health. PPCP have been detected in surface water and wastewater in the ng/L to µg/L concentration range worldwide. PPCP ecotoxicity has been studied in a variety of organisms, and multiple methods have been used to assess the risk of PPCP in the environment to ecological health. Here we review the occurrence, effects, and risk assessment of PPCP in aquatic systems, as well as the sustainability of current methods for managing PPCP contamination in aquatic systems. The major points are the following: (1) a number of PPCP present potential concerns at environmentally relevant concentrations. PPCP mixtures may produce synergistic toxicity. (2) Various methods have been used for the ecological risk assessment of PPCP in aquatic systems. There are similarities in these methods, but no consensus has emerged regarding best practices for the ecological risk assessment of these compounds. (3) Human health risk assessments of PPCP contamination in aquatic systems have generally indicated little cause for concern. However, there is a lack of information regarding whether antibiotic contamination in wastewater and aquatic systems could lead to an increase in clinically relevant antibiotic-resistant bacteria and antibiotic-resistant genes. (4) Over the next century, the combination of increasing global population size and potential droughts may result in reduced water availability, increased need for water reuse, and increasing concentrations of PPCP in wastewaters. The current wastewater treatment methods do not remove all PPCP effectively. This, coupled with the possibility that antibiotics may promote the development of antibiotic-resistant bacteria and antibiotic-resistant genes, leads to concerns about the sustainability of global water supplies.

Discrimination of the effects on zebrafish reproduction from pollutants in drinking water via female, via male and/or via fecundation water

The lack of preventive policy legislation and the low removal rate of organic pollutants in conventional potabilization treatments lead to some of them being present in drinking water. The problem arises because some of these substances have detrimental effects on human reproduction health, via females, via males or even both. In this work, we established the zebrafish as a bioindicator of these types of substances with the goal of discriminating the effects through three different pathways: male, female or water where the fertilization took place.

For this purpose, four parameters were analysed: fertility rate, hatching rate and survival and abnormalities rates. So, for each parameter two groups were formed, according to whether adult males or females were reared in bottled spring water (Z) or tap water (B) and if the in vitro fertilization took place in water Z or B.

Results revealed a decline in the fertility and hatching rate in water B, due to a water effect. The most plausible explanation could be the presence of substances which affect the micropyle and chorion. Moreover, a decrease in the fertility rate due to an effect over the female was also observed, but in this case by an alteration of the oocyte quality.

Zebrafish as a possible bioindicator of organic pollutants with effects on reproduction in drinking waters

Organic contaminants can be detected at low concentrations in drinking water, raising concerns for human health, particularly in reproduction. In this respect, we attempted to use the zebrafish as a bioindicator to detect the possible presence of these substances in drinking water, aiming to define the most relevant parameters to detect these substances, which particularly affect the development and reproduction of zebrafish. To this end, batches of 30 embryos with the chorion intact were cultured in drinking waters from different sources, throughout their full life-cycle up to 5 months, in 20 L tanks. Six replicates were performed in all water groups, with a total of 24 aquariums. Two generations (F0 and F1) were studied and the following parameters were tested: in the F0 generation, survival and abnormality rates evaluated at 5 dpf (days post-fertilization) and at 5 mpf (months post-fertilization), the onset of spawning and the fertility rate from 3 mpf to 5 mpf, and the sex ratio and underdeveloped specimens at 5 mpf. Furthermore, in the F0 offspring (F1), survival and abnormality rates were evaluated at 5 dpf and the hatching rate at 72 hpf. These results revealed that the hatching rate is the most sensitive parameter to distinguish different levels of effects between waters during the early life stages, whereas the rate of underdeveloped specimens is more suitable at later life stages. Regarding adult reproduction, fertility rate was the most sensitive parameter. The possible reversibility or accumulative nature of such effects will be studied in future work.

Pharmaceuticals and personal care products: A critical review of the impacts on fish reproduction

Research in environmental toxicology involving pharmaceuticals and personal care products (PPCPs) has increased greatly over the last 10-15 years. Much research has been focused on the endocrine-disrupting potential of PPCPs, as they relate to negative population impacts of aquatic organisms. This review assesses the current data on the reported effects of PPCPs on fish reproduction with an emphasis on fecundity, a predictor of population effects. Studies of both individual PPCPs and PPCP mixtures are presented. As the majority of individual PPCP studies reviewed demonstrate negative effects on fish fecundity, we relate these findings to detected surface water concentrations of these compounds. Very few studies involving PPCP mixtures have been conducted; however, the need for these types of studies is warranted as fish are most likely exposed to mixtures of PPCPs in the wild. In addition, laboratory and field assessments of wastewater treatment plant (WWTP) effluents, a major source of PPCPs, are reviewed. Much of the data provided from these assessments are variable and do not generally demonstrate negative impacts on reproduction, or the studies are unable to directly associate observed effects with WWTP effluents. Finally, future research considerations are outlined to provide an avenue into understanding how wild populations of fish are affected by PPCPs. These considerations are aimed at determining the adaptation potential of fish exposed to mixtures of PPCPs over multiple generations. As global use of PPCPs continually rises, the need to discern the effects of chronic exposure to PPCPs is greatly increased.

Biological plausibility as a tool to associate analytical data for micropollutants and effect potentials in wastewater, surface water, and sediments with effects in fishes

Discharge of substances like pesticides, pharmaceuticals, flame retardants, and chelating agents in surface waters has increased over the last decades due to the rising numbers of chemicals used by humans and because many WWTPs do not eliminate these substances entirely. The study, results of which are presented here, focused on associations of (1) concentrations of micropollutants in wastewater treatment plant (WWTP) effluents, surface waters, sediments, and tissues of fishes; (2) results of laboratory biotests indicating potentials for effects in these samples and (3) effects either in feral chub (Leuciscus cephalus) from two German rivers (Schussen, Argen) or in brown trout (Salmo trutta f. fario) and rainbow trout (Oncorhynchus mykiss) exposed in bypass systems to streamwater of these rivers or in cages directly in the rivers. The Schussen and Argen Rivers flow into Lake Constance. The Schussen River is polluted by a great number of chemicals, while the Argen River is less influenced by micropollutants. Pesticides, chelating agents, flame retardants, pharmaceuticals, heavy metals, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were detected in effluents of a WWTP discharging to the Schussen as well as in surface water, and/or fishes from downstream of the WWTP. Results obtained by biotests conducted in the laboratory (genotoxicity, dioxin-like toxicity, and embryotoxicity) were linked to effects in feral fish collected in the vicinity of the WWTP or in fishes exposed in cages or at the bypass systems downstream of the WWTP. Dioxin-like effect potentials detected by reporter gene assays were associated with activation of CYP1A1 enzymes in fishes which are inducible by dioxin-like chemicals. Abundances of several PCBs in tissues of fishes from cages and bypass systems were not associated with these effects but other factors can influence EROD activity. Genotoxic potentials obtained by in vitro tests were associated with the presence of micronuclei in erythrocytes of chub from the river. Chemicals potentially responsible for effects on DNA were identified. Embryotoxic effects on zebrafish (Danio rerio), investigated in the laboratory, were associated with embryotoxic effects in trout exposed in streamwater bypass systems at the two rivers. In general, responses at all levels of organization were more pronounced in samples from the Schussen than in those from the Argen. These results are consistent with the magnitudes of chemical pollution in these two streams. Plausibility chains to establish causality between exposures and effects and to predict effects in biota in the river from studies in the laboratory are discussed.

Rest mutant zebrafish swim erratically and display atypical spatial preferences

The Rest/Nrsf transcriptional repressor modulates expression of a large set of neural specific genes. Many of these target genes have well characterized roles in nervous system processes including development, plasticity and synaptogenesis. However, the impact of Rest-mediated transcriptional regulation on behavior has been understudied due in part to the embryonic lethality of the mouse knockout. To investigate the requirement for Rest in behavior, we employed the zebrafish rest mutant to explore a range of behaviors in adults and larva. Adult rest mutants of both sexes showed abnormal behaviors in a novel environment including increased vertical swimming, erratic swimming patterns and a proclivity for the tank walls. Adult males also had diminished reproductive success. At 6 days post fertilization (dpf), rest mutant larva were hypoactive, but displayed normal evoked responses to light and sound stimuli. Overall, these results provide evidence that rest dysfunction produces atypical swimming patterns and preferences in adults, and reduced locomotor activity in larvae. This study provides the first behavioral analysis of rest mutants and reveals specific behaviors that are modulated by Rest.

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.

Emerging contaminants of public health significance as water quality indicator compounds in the urban water cycle

The contamination of the urban water cycle (UWC) with a wide array of emerging organic compounds (EOCs) increases with urbanization and population density. To produce drinking water from the UWC requires close examination of their sources, occurrence, pathways, and health effects and the efficacy of wastewater treatment and natural attenuation processes that may occur in surface water bodies and groundwater. This paper researches in details the structure of the UWC and investigates the routes by which the water cycle is increasingly contaminated with compounds generated from various anthropogenic activities. Along with a thorough survey of chemicals representing compound classes such as hormones, antibiotics, surfactants, endocrine disruptors, human and veterinary pharmaceuticals, X-ray contrast media, pesticides and metabolites, disinfection-by-products, algal toxins and taste-and-odor compounds, this paper provides a comprehensive and holistic review of the occurrence, fate, transport and potential health impact of the emerging organic contaminants of the UWC. This study also illustrates the widespread distribution of the emerging organic contaminants in the different aortas of the ecosystem and focuses on future research needs.

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 chronic, parental pharmaceutical exposure on zebrafish (Danio rerio) offspring

In this study we explored how parental exposure to pharmaceuticals influences reproduction in offspring. Adult zebrafish (Danio rerio) were exposed for 6 weeks to 10 μgL(-1) of carbamazepine (CBZ) and gemfibrozil (GEM), two commonly prescribed drugs. Embryos were collected, reared in clean water until sexual maturity and then assessed for reproductive output, courtship, sperm function and organ histology. While 34% of the control pairs produced clutches, only 11% of the fish with CBZ exposed parents or 17% of the fish with GEM exposed parents produced clutches. Reciprocal crosses indicated that exposure in males had more profound reproductive effects. When a control F1 male was crossed with either a F1 female whose parents were CBZ or GEM exposed; no differences were observed in embryo production compared to controls. However, when a control F1 female was crossed with either a CBZ or GEM F1 male, 50% less embryos were produced. Male courtship was reduced in both CBZ and GEM F1 fish but the deficits in courtship displays were drug specific. Compared to control males, the sperm from GEM F1 males had shorter head lengths and midpieces whereas sperm from CBZ F1 males had longer midpieces. Although it remains unclear how specifically these morphological differences influenced sperm velocity, the sperm from GEM F1 males and from CBZ F1 males swam faster than the sperm of control F1 at 20s post activation. No significant differences were observed in the histology of the liver, kidney and gonads across treatment groups. These data are important as they show that chronic, low dose pharmaceutical exposure of parental fish is sufficient to cause significant reproductive effects in offspring.

Effects of mixture of pharmaceuticals on early life stages of tench (Tinca tinca)

Ubiquitous occurrence of pharmaceuticals in aquatic environment results in concern about potential adverse the effects on nontarget organisms. In water, drugs are present in complex mixtures, in which complicated interactions affect toxicity of single components. The purpose of this study was to examine effect of 35-day-long exposure to mixture of ibuprofen, diclofenac, and carbamazepine on the mortality, growth, early ontogeny, and histopathological changes in tench (Tinca tinca). Early life stage toxicity test was carried out using a modified protocol according to OECD guideline 210. Exposure to mixture of pharmaceuticals at concentration of 60 μg·L⁻¹ for each substance was associated with significant increase in mortality, as well as significant increase in growth and elevated incidence of malformations. Any of the tested concentrations resulted in histopathological changes of liver, kidney, skin, or gill. After fourteen days of exposure there was short-term delay of development related to increased concentrations of pharmaceuticals in the mixture (2, 20, and 60 μg·L⁻¹). Environmentally relevant concentrations (0.02; and 0.2 μg·L⁻¹) used in this experiment did not result in toxic impairment of tench.

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.

Chronic effects of exposure to a pharmaceutical mixture and municipal wastewater in zebrafish

Pharmaceuticals and personal care products (PPCPs) are discharged in municipal wastewater. Effects in aquatic organisms exposed to individual pharmaceuticals in the laboratory have raised concerns regarding the environmental impacts of PPCPs, yet environmental exposures are always to complex mixtures. In this study, adult zebrafish (Danio rerio) showed significantly decreased embryo production after a 6 week exposure to a pharmaceutical mixture (MIX; 0.5 and 10μgL(-1)) of acetaminophen, carbamazepine, gemfibrozil and venlafaxine and to diluted wastewater effluent (WWE; 5% and 25%). Atretic oocytes and altered ovarian histology were significantly increased in female zebrafish exposed to both concentrations of MIX or WWE, which indicates a direct effect on oocyte development that may account for reduced embryo production. Apoptosis within the thecal and granulosa cell layers was identified in female zebrafish with atresia. Exposures to MIX or WWE at both concentrations severely altered kidney proximal tubule morphology, but no histological impacts on other organs were observed. Exposure of embryos to MIX or WWE at the high concentration significantly increased the incidence of developmental abnormalities. Embryo mortality was elevated with exposure to the high concentration of MIX. These studies indicate that chronic exposure of fish to pharmaceutical mixtures and wastewater impacts reproduction and induces histopathological changes, similar to what we have previously seen with single compound exposures. These data suggest that fish populations exposed to pharmaceuticals discharged in wastewater are at risk of negative impacts to reproductive capacity and health.