Search

The presence of pharmaceuticals in the environment, especially the aquatic environment, has received a lot of attention in the last 20 plus years. Despite that attention, the two most important questions regarding pharmaceuticals in the environment still cannot be answered. It is not possible to put the threat posed by pharmaceuticals into perspective with the many other threats (stressors) facing aquatic organisms, such as low flows due to over-abstraction of water, inhibited passage of migratory species due to dams and weirs, diseases, algal blooms causing low oxygen levels and releasing toxins, eutrophication, climate change, and so on. Nor is it possible to identify which pharmaceuticals are of concern and which are not. Not only can these key questions not be answered presently, they have received extremely little attention, despite being identified 10 years ago as the two most important questions to answer. That situation must change if resources and expertise are to be effectively used to protect the environment. Environ Toxicol Chem 2024;43:589-594. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

There remains a persistent concern that freshwater biodiversity is in decline and being threatened by pollution. As the UK, and particularly England, is a densely populated nation with rivers of modest dilution capacity, this location is very suitable to examine how freshwater biodiversity has responded to human pressures over the past 30 years. A long-term dataset of 223,325 freshwater macroinvertebrate records from 1989 to 2018 for England was retrieved and examined. A sub-set of approximately 200 sites per English Region (1515 sites in total with 62,514 samples), with the longest and most consistent records were matched with predicted wastewater exposure, upstream land cover and terrain characteristics (latitude, altitude, slope gradient and flow discharge). To understand changes in macroinvertebrate diversity and sensitivity with respect to these parameters, the biotic indices of (i) overall family richness, (ii) Ephemeroptera, Plecoptera, Trichoptera (EPT) family richness, and (iii) the Biological Monitoring Working Party (BMWP) scores of NTAXA (number of scoring taxa) and (iv) ASPT (average score per taxon) were selected. A review of how close the BMWP scores come to those expected at minimally impacted reference sites was included. For all latitudes, altitudes, channel slope, river size, wastewater exposure levels, and differing proportions of upstream woodland, seminatural, arable and urban land cover, all diversity or sensitivity indices examined improved over this period, although this improvement has slowed in some cases post 2003. Mean overall family richness has increased from 15 to 25 family groups, a 66 % improvement. The improvement in mean EPT family richness (3 to 10 families, >300 % improvement), which are considered to be particularly sensitive to pollution, implies macroinvertebrate diversity has benefited from a national improvement in critical components of water quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Data availability The data supporting the results in the paper can be archived. We are preparing to submit the data separately. It will be openly available. We are glad to accept any request to view these data if that is desired., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

While chemicals are vital to modern society through materials, agriculture, textiles, new technology, medicines, and consumer goods, their use is not without risks. Unfortunately, our resources seem inadequate to address the breadth of chemical challenges to the environment and human health. Therefore, it is important we use our intelligence and knowledge wisely to prepare for what lies ahead. The present study used a Delphi-style approach to horizon-scan future chemical threats that need to be considered in the setting of chemicals and environmental policy, which involved a multidisciplinary, multisectoral, and multinational panel of 25 scientists and practitioners (mainly from the United Kingdom, Europe, and other industrialized nations) in a three-stage process. Fifteen issues were shortlisted (from a nominated list of 48), considered by the panel to hold global relevance. The issues span from the need for new chemical manufacturing (including transitioning to non-fossil-fuel feedstocks); challenges from novel materials, food imports, landfills, and tire wear; and opportunities from artificial intelligence, greater data transparency, and the weight-of-evidence approach. The 15 issues can be divided into three classes: new perspectives on historic but insufficiently appreciated chemicals/issues, new or relatively new products and their associated industries, and thinking through approaches we can use to meet these challenges. Chemicals are one threat among many that influence the environment and human health, and interlinkages with wider issues such as climate change and how we mitigate these were clear in this exercise. The horizon scan highlights the value of thinking broadly and consulting widely, considering systems approaches to ensure that interventions appreciate synergies and avoid harmful trade-offs in other areas. We recommend further collaboration between researchers, industry, regulators, and policymakers to perform horizon scanning to inform policymaking, to develop our ability to meet these challenges, and especially to extend the approach to consider also concerns from countries with developing economies. Environ Toxicol Chem 2023;42:1212-1228. © 2023 Crown copyright and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland., (© 2023 Crown copyright and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland.)

It is unusual, and can be difficult, for scientists to reflect in their publications on any limitations their research had. This is a consequence of the extreme pressure that scientists are under to 'publish or perish'. The inevitable consequence is that much published research is not as good as it could, and should, be, leading to the current 'reproducibility crisis'. Approaches to address this crisis are required. Our suggestion is to include a 'Limitations' section in all scientific papers. Evidence is provided showing that such a section must be mandatory. Adding a 'Limitations' section to scientific papers would greatly increase honesty, openness and transparency, to the considerable benefit of both the scientific community and society in general. This suggestion is applicable to all scientific disciplines. Finally, we apologise if our suggestion has already been made by others., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: John Sumpter reports financial support was provided by Natural Environment Research Council. Damia Barcelo is serving in an editorial capacity for the journal to which we are submitting (STOTEN)., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The processes underpinning the environmental risk assessment (ERA) of chemicals have not changed appreciably in the last 30 years. It is unclear how successful these processes are in protecting the environment from any adverse effects of chemicals. To ascertain if the current methodology can be improved, and if so, how, we invited experts to suggest how the current ERA process could be improved. They were not asked to select from a list of suggestions. The 36 experts made 109 suggestions for improvement, which could be grouped into 33 categories. The category that received the most support, from 12 experts, was to utilise a broader range of scientific information, including all up-to-date information, in ERAs. The second most popular category, supported by 10 experts, was the suggestion to regulate mixtures of chemicals; the current regulatory process involves chemical-by-chemical assessment. Two quite radical proposals were suggested. One was to replace the regulator with artificial intelligence. The other was to establish a new competent authority that would appoint groups of experts, each including representatives of the range of stakeholders, to decide which studies were required, commission those studies, then conduct the ERA based on the results of those studies. These two radical proposals, which the authors support strongly, are not necessarily mutually exclusive. We conclude that the present ERA process could be improved to better protect the environment from the myriad of chemicals in use., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

There is a growing concern that neuroactive chemicals released into the environment can perturb wildlife behaviour. Among these chemicals, pharmaceuticals such as antidepressants and anxiolytics have been receiving increasing attention, as they are specifically prescribed to modify behavioural responses. Many laboratory studies have demonstrated that some of these compounds can affect various aspects of the behaviour of a range of aquatic organisms; however, these investigations are focused on a very small set of neuroactive pharmaceuticals, and they often consider one compound at a time. In this study, to better understand the environmental and toxicological dimension of the problem, we considered all pharmaceuticals explicitly intended to modulate the central nervous system (CNS), and we hypothesised that these compounds have higher probability of perturbing animal behaviour. Based on this hypothesis, we used the classification of pharmaceuticals provided by the British National Formulary (based on their clinical applications) and identified 210 different CNS-acting pharmaceuticals prescribed in the UK to treat a variety of CNS-related conditions, including mental health and sleep disorders, dementia, epilepsy, nausea, and pain. The analysis of existing databases revealed that 84 of these compounds were already detected in surface waters worldwide. Using a biological read-across approach based on the extrapolation of clinical data, we predicted that the concentration of 32 of these neuroactive pharmaceuticals in surface waters in England may be high enough to elicit pharmacological effects in wild fish. The ecotoxicological effects of the vast majority of these compounds are currently uncharacterised. Overall, these results highlight the importance of addressing this environmental challenge from a mixture toxicology and systems perspective. The knowledge platform developed in the present study can guide future region-specific prioritisation efforts, inform the design of mixture studies, and foster interdisciplinary efforts aimed at identifying novel approaches to predict and interpret the ecological implications of chemical-induced behaviour disruption.

A comprehensive aquatic environmental risk assessment (ERA) of the human pharmaceutical propranolol was conducted, based on all available scientific literature. Over 200 papers provided information on environmental concentrations (77 of which provided river concentrations) and 98 dealt with potential environmental effects. The median concentration of propranolol in rivers was 7.1 ng/L (range of median values of individual studies 0.07 to 89 ng/L), and the highest individual value was 590 ng/L. Sixty-eight EC50 values for 35 species were available. The lowest EC50 value was 0.084 mg/L. A species sensitivity distribution (SSD) provided an HC50 value of 6.64 mg/L and an HC5 value of 0.22 mg/L. Thus, there was a difference of nearly 6 orders of magnitude between the median river concentration and the HC50 value, and over 4 orders of magnitude between the median river concentration and the HC5 value. Even if an assessment factor of 100 was applied to the HC5 value, to provide considerable protection to all species, the safety margin is over 100-fold. However, nearly half of all papers reporting effects of propranolol did not provide an EC50 value. Some reported that very low concentrations of propranolol caused effects. The lowest concentration reported to cause an effect - in fact, a range of biochemical and physiological effects on mussels - was 0.3 ng/L. In none of these 'low concentration' papers was a sigmoidal concentration-response relationship obtained. Although inclusion of data from these papers in the ERA cause a change in the conclusion reached, we are sceptical of the repeatability of these 'low concentration' results. We conclude that concentrations of propranolol present currently in rivers throughout the world do not constitute a risk to aquatic organisms. We discuss the need to improve the quality of ecotoxicology research so that more robust ERAs acceptable to all stakeholders can be completed., Competing Interests: Declaration of competing interest This study was partially funded by the pharmaceutical company AstraZeneca, and one of the authors (SFO) is an employee of that company. However, the literature searches, identification of relevant research, extraction of information, and writing the complete first draft of the paper were all conducted entirely by the university-based authors, with no interference from any employee of AstraZeneca. SFO and other employees of AstraZeneca subsequently improved that initial draft, but none of the data, or their interpretation, were changed during that process., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

As we attempt to manage chemicals in the environment we need to be sure that our research efforts are being directed at the substances of greatest threat. All too often we focus on a chemical of concern and then cast around for evidence of its effects in an unstructured way. Risk assessment based on laboratory ecotoxicity studies, combined with field chemical measurements, can only take us so far. Uncertainty about the range and sufficiency of evidence required to take restorative action often puts policymakers in a difficult situation. We review this conundrum and reflect on how the "Hill criteria," used widely by epidemiologists, have been applied to a weight-of-evidence approach (a term sometimes used interchangeably with ecoepidemiology) to build a case for causation. While using a set of such criteria to address sites of local environmental distress has been embraced by the US Environmental Protection Agency, we urge a wider adoption of weight-of-evidence approaches by policymakers, regulators, and scientists worldwide. A simplified series of criteria is offered. Progress will require a sustained commitment to long-term wildlife and chemical monitoring over a sufficient geographic spread. Development of a comprehensive monitoring network, coupled with assembling evidence of harm in a structured manner, should be the foundation for protecting our ecosystems and human health. This will enable us to not only judge the success or failure of our efforts but also diagnose underlying causes. Environ Toxicol Chem 2021;40:2968-2977. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Steroid hormones are extremely important natural hormones in all vertebrates. They control a wide range of physiological processes, including osmoregulation, sexual maturity, reproduction and stress responses. In addition, many synthetic steroid hormones are in widespread and general use, both as human and veterinary pharmaceuticals. Recent advances in environmental analytical chemistry have enabled concentrations of steroid hormones in rivers to be determined. Many different steroid hormones, both natural and synthetic, including transformation products, have been identified and quantified, demonstrating that they are widespread aquatic contaminants. Laboratory ecotoxicology experiments, mainly conducted with fish, but also amphibians, have shown that some steroid hormones, both natural and synthetic, can adversely affect reproduction when present in the water at extremely low concentrations: even sub-ng/L. Recent research has demonstrated that mixtures of different steroid hormones can inhibit reproduction even when each individual hormone is present at a concentration below which it would not invoke a measurable effect on its own. Limited field studies have supported the conclusions of the laboratory studies that steroid hormones may be environmental pollutants of significant concern. Further research is required to identify the main sources of steroid hormones entering the aquatic environment, better describe the complex mixtures of steroid hormones now known to be ubiquitously present, and determine the impacts of environmentally-realistic mixtures of steroid hormones on aquatic vertebrates, especially fish. Only once that research is completed can a robust aquatic risk assessment of steroid hormones be concluded., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Knowledge of the hazards and associated risks from chemicals discharged to the environment has grown considerably over the past 40 years. This improving awareness stems from advances in our ability to measure chemicals at low environmental concentrations, recognition of a range of effects on organisms, and a worldwide growth in expertise. Environmental scientists and companies have learned from the experiences of the past; in theory, the next generation of chemicals will cause less acute toxicity and be less environmentally persistent and bioaccumulative. However, researchers still struggle to establish whether the nonlethal effects associated with some modern chemicals and substances will have serious consequences for wildlife. Obtaining the resources to address issues associated with chemicals in the environment remains a challenge., (Copyright © 2020, American Association for the Advancement of Science.)

A "reproducibility crisis" is widespread across scientific disciplines, where results and conclusions of studies are not supported by subsequent investigation. Here we provide a steroid immunoassay example where human errors generated unreproducible results and conclusions. Our study was triggered by a scientific report citing abnormally high concentrations (means of 4-79 ng L -1 ) of three natural sex steroids [11-ketotestosterone (11-KT), testosterone (T) and oestradiol (E2)] in water samples collected from two UK rivers over 4 years (2002-6). Furthermore, the data suggested that trout farms were a major source because reported steroid concentrations were 1.3-6 times higher downstream than upstream. We hypothesised that the reported levels were erroneous due to substances co-extracted from the water causing matrix effects (i.e. "false positives") during measurement by enzyme-linked immunoassay (EIA). Thus, in collaboration with three other groups (including the one that had conducted the 2002-6 study), we carried out field sampling and assaying to examine this hypothesis. Water samples were collected in 2010 from the same sites and prepared for assay using an analogous method [C18 solid phase extraction (SPE) followed by extract clean-up with aminopropyl SPE]. Additional quality control ("spiked" and "blank") samples were processed. Water extracts were assayed for steroids using radioimmunoassay (RIA) as well as EIA. Although there were statistically significant differences between EIA and RIA (and laboratories), there was no indication of matrix effects in the EIAs. Both the EIAs and RIAs (uncorrected for recovery) measured all three natural steroids at <0.6 ng L -1 in all river water samples, indicating that the trout farms were not a significant source of natural steroids. The differences between the two studies were considerable: E2 and T concentrations were ca. 100-fold lower and 11-KT ca. 1000-fold lower than those reported in the 2002-6 study. In the absence of evidence for any marked changes in husbandry practice (e.g. stock, diet) or environmental conditions (e.g. water flow rate) between the study periods, we concluded that calculation errors were probably made in the first (2002-6) study associated with confusion between extract and water sample concentrations. The second (2010) study also had several identified examples of calculation error (use of an incorrect standard curve; extrapolation below the minimum standard; confusion of assay dilutions during result work-up; failure to correct for loss during extraction) and an example of sample contamination. Similar and further errors have been noted in other studies. It must be recognised that assays do not provide absolute measurements and are prone to a variety of errors, so published steroid levels should be viewed with caution until independently confirmed., (Crown Copyright © 2019. Published by Elsevier Inc. All rights reserved.)

Despite the undoubted interest in assessing the performance and impact of scientists, there appears to be no generally accepted way of doing so. Their research papers can be assessed by various metrics, but these cover only one aspect of the activities of a scientist. In this paper I provide my own thoughts on many of the aspects I consider make up a good research scientist. However, these are my opinions only; they are often not supported by available quantitative, or even qualitative, evidence. I have then applied these criteria to one individual scientist, the ecotoxicologist Karl Fent. I show that he has contributed significantly to his chosen discipline in a number of distinct ways, through both his teaching and his research. I therefore conclude that he must be considered a very good scientist. In the current era of attempting to quantify and hence rank almost everything, an approach often driven by lack of trust, it is very clear that there is substantial scope in attempting to develop, then utilize appropriately, objective criteria that are informative of a scientist's contributions. Those criteria need to be much broader than the metrics currently available., (Copyright © 2019 The Author. Published by Elsevier B.V. All rights reserved.)

There is concern that psychoactive drugs present in the aquatic environment could affect the behaviour of fish, and other organisms, adversely. There is considerable experimental support for this concern, although the literature is not consistent. To investigate why, fish were exposed to three concentrations of the synthetic opiate tramadol for 23-24 days, and their anxiolytic behaviour in a novel tank diving test was assessed both before and after exposure. The results were difficult to interpret. The positive control drug, the anti-depressant fluoxetine, produced the expected results: exposed fish explored the novel tank more, and swam more slowly while doing so. An initial statistical analysis of the results provided relatively weak support for the conclusion that both the low and high concentrations of tramadol affected fish behaviour, but no evidence that the intermediate concentration did. To gain further insight, UK and Japanese experts in ecotoxicology were asked for their independent opinions on the data for tramadol. These were highly valuable. For example, about half the experts replied that a low concentration of a chemical can cause effects that higher concentrations do not, although a similar number did not believe this was possible. Based both on the inconclusive effects of tramadol on the behaviour of the fish and the very varied opinions of experts on the correct interpretation of those inconclusive data, it is obvious that more research on the behavioural effects of tramadol, and probably all other psychoactive drugs, on aquatic organisms is required before any meaningful risk assessments can be conducted. The relevance of these findings may apply much more widely than just the environmental risk assessment of psychoactive drugs. They suggest that much more rigorous training of research scientists and regulators is probably required if consensus decisions are to be reached that adequately protect the environment from chemicals., (Copyright © 2019 Elsevier B.V. All rights reserved.)

High-profile reports of detrimental scientific practices leading to retractions in the scientific literature contribute to lack of trust in scientific experts. Although the bulk of these have been in the literature of other disciplines, environmental toxicology and chemistry are not free from problems. While we believe that egregious misconduct such as fraud, fabrication of data, or plagiarism is rare, scientific integrity is much broader than the absence of misconduct. We are more concerned with more commonly encountered and nuanced issues such as poor reliability and bias. We review a range of topics including conflicts of interests, competing interests, some particularly challenging situations, reproducibility, bias, and other attributes of ecotoxicological studies that enhance or detract from scientific credibility. Our vision of scientific integrity encourages a self-correcting culture that promotes scientific rigor, relevant reproducible research, transparency in competing interests, methods and results, and education. Integr Environ Assess Manag 2019;00:000-000. © 2019 SETAC., (© 2019 SETAC.)

Endocrine disrupting chemicals (EDCs) are substances that alter the function of the endocrine system and consequently cause adverse effects to humans or wildlife. The release of particular EDCs into the environment has been shown to negatively affect certain wildlife populations and has led to restrictions on the use of some EDCs. Current chemical regulations aim to balance the industrial, agricultural and/or pharmaceutical benefits of using these substances with their demonstrated or potential harm to human health or the environment. A summary is provided of the natural science evidence base informing the regulation of chemicals released into the environment that may have endocrine disrupting effects on wildlife. This summary is in a format (a 'restatement') intended to be policy-neutral and accessible to informed, but not expert, policy-makers and stakeholders.

Ill-defined, multi-component mixtures of steroidal pharmaceuticals are present in the aquatic environment. Fish are extremely sensitive to some of these steroids. It is important to know how fish respond to these mixtures, and from that knowledge develop methodology that enables accurate prediction of those responses. To provide some of the data required to reach this objective, pairs of fish were first exposed to five different synthetic steroidal pharmaceuticals (one estrogen, EE2; one androgen, trenbolone; one glucocorticoid, beclomethasone dipropionate; and two progestogens, desogestrel and levonorgestrel) and concentration-response data on egg production obtained. Based on those concentration-response relationships, a five component mixture was designed and tested twice. Very similar effects were observed in the two experiments. The mixture inhibited egg production in an additive manner predicted better by the model of Independent Action than that of Concentration Addition. Our data provide a reference case for independent action in an in vivo model. A significant combined effect was observed when each steroidal pharmaceutical in the mixture was present at a concentration which on its own would produce no statistically significant effect (something from 'nothing'). Further, when each component was present in the mixture at a concentration expected to inhibit egg production by between 18% (Beclomethasone diproprionate) and 40% (trenbolone), this mixture almost completely inhibited egg production: a phenomenon we term 'a lot from a little'. The results from this proof-of-principle study suggest that multiple steroids present in the aquatic environment can be analysed for their potential combined environmental risk., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

This work presents a new and unbiased method of risk ranking chemicals based on the threat they pose to the aquatic environment. The study ranked 12 metals, 23 pesticides, 11 other persistent organic pollutants (POPs), 13 pharmaceuticals, 10 surfactants and similar compounds and 2 nanoparticles (total of 71) of concern against one another by comparing their median UK river water and median ecotoxicity effect concentrations. To complement this, by giving an assessment on potential wildlife impacts, risk ranking was also carried out by comparing the lowest 10th percentile of the effects data with the highest 90th percentile of the exposure data. In other words, risk was pared down to just toxicity versus exposure. Further modifications included incorporating bioconcentration factors, using only recent water measurements and excluding either lethal or sub-lethal effects. The top ten chemicals, based on the medians, which emerged as having the highest risk to organisms in UK surface waters using all the ecotoxicity data were copper, aluminium, zinc, ethinylestradiol (EE2), linear alkylbenzene sulfonate (LAS), triclosan, manganese, iron, methomyl and chlorpyrifos. By way of contrast, using current UK environmental quality standards as the comparator to median UK river water concentrations would have selected 6 different chemicals in the top ten. This approach revealed big differences in relative risk; for example, zinc presented a million times greater risk then metoprolol and LAS 550 times greater risk than nanosilver. With the exception of EE2, most pharmaceuticals were ranked as having a relatively low risk., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Recent species-extrapolation approaches to the prediction of the potential effects of pharmaceuticals present in the environment on wild fish are based on the assumption that pharmacokinetics and metabolism in humans and fish are comparable. To test this hypothesis, we exposed fathead minnows to the opiate pro-drug tramadol and examined uptake from the water into the blood and brain and the metabolism of the drug into its main metabolites. We found that plasma concentrations could be predicted reasonably accurately based on the lipophilicity of the drug once the pH of the water was taken into account. The concentrations of the drug and its main metabolites were higher in the brain than in the plasma, and the observed brain and plasma concentration ratios were within the range of values reported in mammalian species. This fish species was able to metabolize the pro-drug tramadol into the highly active metabolite O-desmethyl tramadol and the inactive metabolite N-desmethyl tramadol in a similar manner to that of mammals. However, we found that concentration ratios of O-desmethyl tramadol to tramadol were lower in the fish than values in most humans administered the drug. Our pharmacokinetic data of tramadol in fish help bridge the gap between widely available mammalian pharmacological data and potential effects on aquatic organisms and highlight the importance of understanding drug uptake and metabolism in fish to enable the full implementation of predictive toxicology approaches.

The quality and reproducibility of science has recently come under scrutiny, with criticisms spanning disciplines. In aquatic toxicology, behavioural tests are currently an area of controversy since inconsistent findings have been highlighted and attributed to poor quality science. The problem likely relates to limitations to our understanding of basic behavioural patterns, which can influence our ability to design statistically robust experiments yielding ecologically relevant data. The present study takes a first step towards understanding baseline behaviours in fish, including how basic choices in experimental design might influence behavioural outcomes and interpretations in aquatic toxicology. Specifically, we explored how fish acclimate to behavioural arenas and how different lengths of observation time impact estimates of basic swimming parameters (i.e., average, maximum and angular velocity). We performed a semi-quantitative literature review to place our findings in the context of the published literature describing behavioural tests with fish. Our results demonstrate that fish fundamentally change their swimming behaviour over time, and that acclimation and observational timeframes may therefore have implications for influencing both the ecological relevance and statistical robustness of behavioural toxicity tests. Our review identified 165 studies describing behavioural responses in fish exposed to various stressors, and revealed that the majority of publications documenting fish behavioural responses report extremely brief acclimation times and observational durations, which helps explain inconsistencies identified across studies. We recommend that researchers applying behavioural tests with fish, and other species, apply a similar framework to better understand baseline behaviours and the implications of design choices for influencing study outcomes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Students and academic researchers conduct a diverse range of studies that add to the growing body of ecotoxicology research. Once an academic researcher entertains an applied research topic, there is potential for that research to be used in local, state, or federal regulatory decision or action. The ability of regulatory decision makers to use academic studies to inform decisions is dependent on: 1) the relevance of the experiment to regulatory decisions, 2) the reliability of the laboratory and the study itself, and 3) quality reporting of data such that study relevance and reliability are evident. The purpose of this brief communication is to highlight actions that can be taken by Society of Environmental Toxicology and Chemistry members to enhance the usability of academic research studies in regulatory decision making by promoting training, partnerships, and communication. Integr Environ Assess Manag 2017;13:580-584. © 2016 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC)., (© 2016 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).)

There is increasing awareness that the value of peer-reviewed scientific literature is not consistent, resulting in a growing desire to improve the practice and reporting of studies. This is especially important in the field of ecotoxicology, where regulatory decisions can be partly based on data from the peer-reviewed literature, with wide-reaching implications for environmental protection. Our objective is to improve the reporting of ecotoxicology studies so that they can be appropriately utilized in a fair and transparent fashion, based on their reliability and relevance. We propose a series of nine reporting requirements, followed by a set of recommendations for adoption by the ecotoxicology community. These reporting requirements will provide clarity on the the test chemical, experimental design and conditions, chemical identification, test organisms, exposure confirmation, measurable endpoints, how data are presented, data availability and statistical analysis. Providing these specific details will allow for a fuller assessment of the reliability and relevance of the studies, including limitations. Recommendations for the implementation of these reporting requirements are provided herein for practitioners, journals, reviewers, regulators, stakeholders, funders, and professional societies. If applied, our recommendations will improve the quality of ecotoxicology studies and their value to environmental protection., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Progesterone is a natural hormone, excreted in higher concentrations than estrogens, and has been detected in the aqueous environment. As with other compounds, it is transformed during wastewater treatment processes and in the environment. However, minor modifications to the structure may result in transformation products which still exhibit biological activity, so understanding what transformation products are formed is of importance. The current study was undertaken to identify putative transformation products resulting from spiking river water with progesterone in a laboratory-based degradation study and hence to follow the metabolic breakdown pathways. On the basis of literature reports and predictions from the EAWAG Biocatalysis/biodegradation database, target putative transformation products were initially monitored under unit resolution mass spectrometry. The identity of these transformation products was confirmed by using accurate-mass quadrupole time-of-flight. The study results highlight that transformation of progesterone can potentially create other classes of steroids, some of which may still be potent, and possess other types of biological activity., (Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.)

Human pharmaceuticals present in the environment have the potential to cause adverse effects on non-target organisms. The "read-across hypothesis" stipulates that pharmaceuticals will exhibit similar biological effects across species (e.g. human and fish) if the molecular target has been conserved and the effective drug concentrations are reached (Cmax). We tested this hypothesis by evaluating if ibuprofen, a non-selective inhibitor of prostaglandins and the cyclooxygenase (COX) enzyme, can mimic its primary effect in humans, on fish, at comparable plasma concentrations. The endpoints, prostaglandin E metabolite (PGEM) levels and the mRNA expression of COX (ptgs) gene, were measured in the gills of control and exposed fathead minnows (Pimephales promelas), using enzyme-immunoassay and quantitative real-time PCR (qPCR). Fish were exposed, for 24-72 h, to measured water concentrations of 9 (n = 12), 370 (n = 40) and 470 μg ibuprofen/L (n = 12). Water and blood plasma concentrations were determined using LC-MS/MS. Results showed that PGEM levels in fish exposed to 370 and 470 μg ibuprofen/L were significantly decreased compared to control fish, when mean plasma ibuprofen concentrations were 1.8-5.6-fold below the Cmax. The plasma ibuprofen concentrations and PGEM levels varied greatly between individuals. In fish exposed to 9 μg ibuprofen/L, when the mean plasma ibuprofen concentration was 224-fold below Cmax, no change in PGEM levels was observed. These data provide evidence for the read-across hypothesis, but suggest establishing a direct dose-response between internal plasma and PGEM is difficult, and would require significantly larger numbers of fish to overcome the inter-individual variation., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Psychoactive drugs are frequently detected in the aquatic environment. The evolutionary conservation of the molecular targets of these drugs in fish suggests that they may elicit mode of action-mediated effects in fish as they do in humans, and the key open question is at what exposure concentrations these effects might occur. In the present study, the authors investigated the uptake and tissue distribution of the benzodiazepine oxazepam in the fathead minnow (Pimephales promelas) after 28 d of waterborne exposure to 0.8 μg L -1 , 4.7 μg L -1 , and 30.6 μg L -1 . Successively, they explored the relationship between the internal concentrations of oxazepam and the effects on fish exploratory behavior quantified by performing 2 types of behavioral tests, the novel tank diving test and the shelter-seeking test. The highest internal concentrations of oxazepam were found in brain, followed by plasma and liver, whereas muscle presented the lowest values. Average concentrations measured in the plasma of fish from the 3 exposure groups were, respectively, 8.7 ± 5.7 μg L -1 , 30.3 ± 16.1 μg L -1 , and 98.8 ± 72.9 μg L -1 . Significant correlations between plasma and tissue concentrations of oxazepam were found in all 3 groups. Exposure of fish to 30.6 µg L -1 in water produced plasma concentrations within or just below the human therapeutic plasma concentration (H T PC) range in many individuals. Statistically significant behavioral effects in the novel tank diving test were observed in fish exposed to 4.7 μg L -1 . In this group, plasma concentrations of oxazepam were approximately one-third of the lowest H T PC value. No significant effects were observed in fish exposed to the lowest and highest concentrations. The significance of these results is discussed in the context of the species-specific behavior of fathead minnow and existing knowledge of oxazepam pharmacology. Environ Toxicol Chem 2016;35:2782-2790. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC., (© 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.)

The goal of protecting the aquatic environment through testing thousands of chemicals against hundreds of aquatic species with thousands of endpoints while also considering mixtures is impossible given the present resources. Much of the impetus for studies on micropollutants, such as pharmaceuticals, came from the topic of endocrine disruption in wild fish. But despite concern over reductions in fish fertility, there is little evidence that fish populations are in peril. Indeed, fish biologists suggest that many cyprinid populations have been recovering for the past 30 to 40 yr. The central assumption, key to current risk assessment, that effects observed in the laboratory or predicted by models are readily transferrable to the population level, is therefore questionable. The neglect in monitoring wildlife populations is the key weakness in environmental protection strategies. If we do not know whether aquatic wildlife species are declining or increasing, how valuable are our other ecotoxicological activities? Environ Toxicol Chem 2016;35:1609-1616. © 2016 SETAC., (© 2016 SETAC.)

Aquatic organisms can be exposed to thousands of chemicals discharged by the human population. Many of these chemicals are considered disruptive to aquatic wildlife, and the literature on the impacts of these chemicals grows daily. However, because time and resources are not infinite, research must focus on the chemicals that represent the greatest threat. One group of chemicals of increasing concern is pharmaceuticals, for which the primary challenge is to identify which represent the greatest threat. In the present study, a list of 12 pharmaceuticals was compiled based on scoring the prevalence of different compounds from previous prioritization reviews. These included rankings based on prescription data, environmental concentrations, predicted environmental concentration/predicted no-effect concentration (PEC/PNEC) ratios, persistency/bioaccumulation/(eco)toxicity (PBT), and fish plasma model approaches. The most frequently cited were diclofenac, paracetamol, ibuprofen, carbamazepine, naproxen, atenolol, ethinyl estradiol, aspirin, fluoxetine, propranolol, metoprolol, and sulfamethoxazole. For each pharmaceutical, literature on effect concentrations was compiled and compared with river concentrations in the United Kingdom. The pharmaceuticals were ranked by degree of difference between the median effect and median river concentrations. Ethinyl estradiol was ranked as the highest concern, followed by fluoxetine, propranolol, and paracetamol. The relative risk of these pharmaceuticals was compared with those of metals and some persistent organic pollutants. Pharmaceuticals appear to be less of a threat to aquatic organisms than some metals (Cu, Al, Zn) and triclosan, using this ranking approach., (© 2015 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.)

The Adverse Outcome Pathway (AOP) framework represents a valuable conceptual tool to systematically integrate existing toxicological knowledge from a mechanistic perspective to facilitate predictions of chemical-induced effects across species. However, its application for decision-making requires the transition from qualitative to quantitative AOP (qAOP). Here we used a fish model and the synthetic glucocorticoid beclomethasone dipropionate (BDP) to investigate the role of chemical-specific properties, pharmacokinetics, and internal exposure dynamics in the development of qAOPs. We generated a qAOP network based on drug plasma concentrations and focused on immunodepression, skin androgenisation, disruption of gluconeogenesis and reproductive performance. We showed that internal exposure dynamics and chemical-specific properties influence the development of qAOPs and their predictive power. Comparing the effects of two different glucocorticoids, we highlight how relatively similar in vitro hazard-based indicators can lead to different in vivo risk. This discrepancy can be predicted by their different uptake potential, pharmacokinetic (PK) and pharmacodynamic (PD) profiles. We recommend that the development phase of qAOPs should include the application of species-specific uptake and physiologically-based PK/PD models. This integration will significantly enhance the predictive power, enabling a more accurate assessment of the risk and the reliable transferability of qAOPs across chemicals.

The aquatic environment is polluted with thousands of chemicals. It is currently unclear which of these pose a significant threat to aquatic biota. The typical exposure scenario is now represented by a widespread blanket of contamination composed of myriads of individual pollutants-each typically present at a low concentration. The synthetic steroids, 17α-ethinylestradiol and levonorgestrel, have been widely reported to be present in the aquatic environment in the low ng to sub-ng/l range. They are widely used in contraceptive formulations, both individually and in combination. Our research employed the fathead minnow (Pimephales promelas) 21 day 'pair-breeding' assay to assess reproductive output when pairs of fish were exposed to the single chemicals at low environmentally relevant concentrations, and then to a binary mixture of them. A variety of endpoints were assessed, including egg production, which was inhibited in a concentration-dependent manner by both the individual chemicals and the mixture. Significant, sex specific effects were also seen with both chemicals, at differing levels of biological organisation. Plasma concentrations of EE2 and levonorgestrel were predicted and in the case of levonorgestrel measured, and compared with the human therapeutic plasma concentrations (Read-Across approach) to support the interpretation of the results. A novel quantitative method was developed for the data analysis, which ensured a suitable endpoint for the comparative mixture assessment. This approach compares the reproductive performance from individual pairs of fish during chemical exposure to its pre-treatment performance. The responses from the empirical mixture study were compared to predictions derived from the single substance data. We hypothesised combined responses which were best described by the concept of concentration addition, and found no clear indications against this additivity expectation. However, the effect profiles support the current knowledge that both compounds act in different ways to reduce egg production in fish, and suggest that probably response addition (also called Independent action) is the more appropriate mixture model in this case., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)