Single and combined effects of selected pharmaceuticals at sublethal concentrations on multiple biomarkers in Carassius auratus

Antagonistic interaction between caffeine and ketamine in zebrafish: Implications for aquatic toxicity

The coexistence of caffeine (CF) and ketamine (KET) in surface waters across Asia has been widely reported. Previous studies have implied that CF and KET may share a mechanism of action. However, the combined toxicity of these two chemicals on aquatic organisms remains unclear at environmental levels, and the underlying mechanisms are not well understood. Here we demonstrate that KET antagonizes the adverse effects of CF on zebrafish larvae by modulating the gamma-aminobutyric acid (GABA)ergic synapse pathway. Specifically, KET (10-250 ng L-1) ameliorates the locomotor hyperactivity and impaired circadian rhythms in zebrafish larvae induced by 2 mg L-1 of CF, showing a dose-dependent relationship. Additionally, the developmental abnormalities in zebrafish larvae exposed to CF are mitigated by KET, with an incidence rate reduced from 26.7% to 6.7%. The competition between CF and KET for binding sites on the GABA-A receptor (in situ and in silico) elucidates the antagonistic interactions between the two chemicals. Following a seven-day recovery period, the adverse outcomes of CF exposure persist in the fish, whereas the changes observed in the CF + KET groups are significantly alleviated, especially with KET at 10 ng L-1. Based on these results, it is imperative to further assess the environmental risks associated with CF and KET co-pollution. This pilot study underscores the utility of systems toxicology approaches in estimating the combined toxicity of environmental chemicals on aquatic organisms. Moreover, the nighttime behavioral functions of fish could serve as a sensitive biomarker for evaluating the toxicity of psychoactive substances.

From bacteria to fish: ecotoxicological insights into sulfamethoxazole and trimethoprim

Sulfamethoxazole (SMX) and trimethoprim (TRIM) are two of the most used antibiotics in the last 50 years, to prevent and treat bacterial infections; however, the available literature about toxicity to non-target organisms is quite discrepant and incomplete. This study aims to assess the SMX and TRIM ecotoxicological effects in standard species: Aliivibrio fischeri (bioluminescence inhibition), Escherichia coli ATCC 25922 (growth inhibition), Lemna minor (growth inhibition and biochemical biomarkers), Daphnia magna (immobilization/mortality, life history traits, and biochemical biomarkers), and Danio rerio (survival, hatching, abnormalities, and biochemical biomarkers). The species tested showed different acute sensitivities to SMX (A. fischeri < D. magna < E. coli < L. minor) and TRIM (L. minor < A. fischeri < D. magna < E. coli). Overall, TRIM reveals less toxicity than SMX, except for E. coli (Ecotoxicological approach based on Antimicrobial Susceptibility Testing - EcoAST procedure). Both antibiotics affect individually (e.g., growth and survival) and sub-individually (e.g., antioxidant defenses) L. minor, D. magna, and D. rerio. This study allowed us to generate relevant data and fill gaps in the literature regarding the effects of SMX and TRIM in aquatic organisms. The here-obtained results can be used to (i) complete and re-evaluate the Safety Data Sheet to improve the assessment of environmental safety and management of national and international entities; (ii) clarify the environmental risks of these antibiotics in aquatic ecosystems reinforcing the inclusion in the 4th Watch List of priority substances to be monitored in whole inland waters by the Water Framework Directive; and (iii) combat the development of antimicrobial resistance, as well as supporting the definition of environmental measurements in the context of European One Health Action Plan. However, it is essential to continue studying these antibiotics to better understand their toxicity at ecologically relevant concentrations and their long-term effects under different climatic change scenarios.

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

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

The effects of temperature and sulfamethoxazole on the growth and photosynthetic characteristics of Phaeodactylum tricornutum

The misuse of antibiotics has brought potential ecological risks to marine ecosystems, especially under a changing climate. Laboratory experiments were conducted to understand the impact of rising temperatures and antibiotic sulfamethoxazole (SMX) abuse on marine diatom Phaeodactylum tricornutum. Temperatures of 21 and 24 °C were optimal for the growth and photosynthetic characteristics of P. tricornutum. When exposed to higher temperatures (≥27 °C), the growth and photosynthesis were inhibited. High concentrations of SMX (≥100 mg/L) caused rapid and acute toxicological effects on the phytoplankton. In contrast, low concentrations of SMX (1 mg/L) exhibited hormesis. When P. tricornutum was exposed to SMX at high temperatures, the stress on the phytoplankton was even more pronounced. This suggests that the combination of rising temperatures and antibiotic pollution may have a more significant negative impact on marine phytoplankton than either stressor alone. Neglecting the interaction between these stressors may lead to underestimating their combined effects on marine ecosystems.

Public perception on human exposure risk: A case study on endocrine disrupting compounds in the environment

Humans are exposed to environmental risks owing to the broad usage of endocrine disrupting compounds (EDCs). However, the subjective evaluation of risk levels and characteristics, as well as the variation in risk processing, have not been thoroughly examined. The objective was to understand the public's perception of the risk associated with human exposure to environmental EDCs and identify any variations in risk perception. In this pioneering study conducted within the distinctive social and cultural context of Malaysia, a developing nation, a quantitative analysis approach was employed to assess the subjective evaluation of risk levels and characteristics among the public while developing a risk perception model. Data gathered from surveys and questionnaires were analyzed to gather information on the public's perception of environmental and health issues pertaining to pesticides, hormones, plastics, medicines, and cosmetics. The analysis revealed that the majority of the public assessed the level of human exposure to environmental risks based on experiential processing, which was influenced by cognitive and affective variables. Interestingly, a higher proportion of individuals in the community had a low risk perception of environmental EDCs, surpassing the overall risk perception by 19.3%. Furthermore, the public showed significant awareness of environmental and health issues related to pesticides, hormones, and plastics but had a lesser inclination to acknowledge the vulnerability of humans to risks associated with medicines and cosmetics. These findings suggest that the public is likely to be exposed to environmental EDCs based on their current perceived risks, and that sociopsychological factors play a significant role in shaping perceptions and judgments. This understanding can inform the development of targeted risk management strategies and interventions to mitigate the potential harm caused by environmental EDCs.

The Impacts of the Multispecies Approach to Caffeine on Marine Invertebrates

Caffeine is one of the most consumed substances by humans through foodstuffs (coffee, tea, drugs, etc.). Its human consumption releases a high quantity of caffeine into the hydrological network. Thus, caffeine is now considered an emergent pollutant sometimes found at high concentrations in oceans and seas. Surprisingly, little research has been conducted on the molecular responses induced by caffeine in marine organisms. We studied, in laboratory conditions, six phylogenetically distant species that perform distinct ecological functions (Actinia equina and Aulactinia verrucosa (cnidarians, predator), Littorina littorea (gastropod, grazer), Magallana gigas (bivalve, filter-feeder), and Carcinus maenas and Pachygrapsus marmoratus (crabs, predator and scavenger)) subjected to caffeine exposure. The antioxidant responses (catalase, CAT; glutathione peroxidase, GPx; superoxide dismutase, SOD), lipid peroxidation (MDA), and the acetylcholinesterase (AChE) activity were estimated when the organisms were exposed to environmental caffeine concentrations (5 μg/L (low), 10 μg/L (high)) over 14 days. Differential levels of responses and caffeine effects were noted in the marine invertebrates, probably in relation to their capacity to metabolization the pollutant. Surprisingly, the filter feeder (M. gigas, oyster) did not show enzymatic responses or lipid peroxidation for the two caffeine concentrations tested. The marine gastropod (grazer) appeared to be more impacted by caffeine, with an increase in activities for all antioxidative enzymes (CAT, GPx, SOD). In parallel, the two cnidarians and two crabs were less affected by the caffeine contaminations. However, caffeine was revealed as a neurotoxic agent to all species studied, inducing high inhibition of AChE activity. This study provides new insights into the sublethal impacts of caffeine at environmentally relevant concentrations in marine invertebrates.

Insights into environmental caffeine contamination in ecotoxicological biomarkers and potential health effects of Danio rerio

Caffeine (CAF) exposures have been shown to cause several pharmacological and biological effects in target and non-target organisms. Although there are already several ecotoxicological studies with CAF in non-target organisms, they are focused on marine organisms, with relevant concentrations in these ecosystems, therefore, less ecologically relevant to freshwater ecosystems (the main ecoreceptor of this type of anthropogenic contaminant). The present study aimed to assess the chronic effects (28 days) of sub-lethal and environmentally relevant concentrations of CAF (0.16, 0.42, 1.09, 2.84, 7.40, 19.23, and 50 μg/L) in Danio rerio. Biochemical endpoints as biomarkers of antioxidant defense, biotransformation, lipid peroxidation, energy sources, and neurotransmission were assessed. CAF exposure induced alterations in antioxidant defenses (superoxide dismutase and glutathione reductase activities, and glutathione content) preventing lipid peroxidation. Lactate dehydrogenase activity decreased in all the concentrations tested, while acetylcholinesterase activity was only affected by the highest concentrations tested (19.23 and 50 μg/L). We also utilized a multi-biomarker approach (Integrated Biomarker Response version 2, IBRv2) to investigate the effects of CAF in the dispersion scope of individual biochemical responses of D. rerio. IBRv2 showed that the concentration of 50 μg/L promotes the highest stress. However, the results showed that CAF induced disturbances in the metabolic pathways studied in D. rerio. These results demonstrated the toxic effects of CAF on freshwater fish, compromising their physiological functions and evidencing the need for monitoring the residues of CAF released into the inland aquatic environments. Furthermore, this research evidence that phylogenetically and physiologically different species may present different biological responses with concern for ecologically relevant environmental conditions. In this sense, the present study generated ecotoxicologically relevant data, that can be considered by environment regulators, since the here-endpoints evaluated showed sensitivity and consistency in the evaluation of caffeine risks in freshwater environments.

International Comparison, Risk Assessment, and Prioritisation of 26 Endocrine Disrupting Compounds in Three European River Catchments in the UK, Ireland, and Spain

Endocrine-disrupting compounds (EDCs) constitute a wide variety of chemistries with diverse properties that may/can pose risks to both humans and the environment. Herein, a total of 26 compounds, including steroids, flame retardants, and plasticizers, were monitored in three major and heavily urbanized river catchments: the R. Liffey (Ireland), the R. Thames (UK), and the R. Ter (Spain), by using a single solid-phase extraction liquid chromatography-mass spectrometry (SPE-LC-MS/MS) method. Occurrence and frequency rates were investigated across all locations over a 10-week period, with the highest concentration obtained for the flame retardant tris(2-chloroethyl) phosphate (TCEP) at 4767 ng∙L-1 in the R. Thames in Central London. Geographical variations were observed between sites and were partially explained using principal component analysis (PCA) and hierarchical cluster analysis (HCA). In particular, discrimination between the R. Ter and the R. Thames was observed based on the presence and concentration of flame retardants, benzotriazole, and steroids. Environmental risk assessment (ERA) across sites showed that caffeine, a chemical marker, and bisphenol A (BPA), a plasticizer, were classified as high-risk for the R. Liffey and R. Thames, based on relative risk quotients (rRQs), and that caffeine was classified as high-risk for the R. Ter, based on RQs. The total risks at each location, namely ΣRQriver, and ΣrRQriver, were: 361, 455, and 723 for the rivers Liffey, Thames, and Ter, respectively. Caffeine, as expected, was ubiquitous in all 3 urban areas, though with the highest RQ observed in the R. Ter. High contributions of BPA were also observed across the three matrices. Therefore, these two compounds should be prioritized independently of location. This study represents a comprehensive EDC monitoring comparison between different European cities based on a single analytical method, which allowed for a geographically independent ERA prioritization to be performed.

Experimentally exposed toxic effects of long-term exposure to environmentally relevant concentrations of CIP in males and females of the silver catfish Rhamdia quelen

Ciprofloxacin (CIP) is an antibiotic commonly used in human and veterinary medicine. It is present in the aquatic environment, but we still know very little about its effect on non-targeted organisms. This study aimed to evaluate the effects of long-term exposure to environmental CIP concentrations (1, 10, and 100 μg.L^-1) in males and females of Rhamdia quelen. After 28 days of exposure, we collected the blood for the analysis of hematological and genotoxic biomarkers. Additionally, we measured 17 β-estradiol and 11 keto-testosterone levels. After the euthanasia, we collected the brain and the hypothalamus to analyze acetylcholinesterase (AChE) activity and neurotransmitters, respectively. The liver and gonads were assessed for biochemical, genotoxic, and histopathological biomarkers. At 100 μg.L^-1 CIP, we observed genotoxicity in the blood, nuclear morphological changes, apoptosis, leukopenia, and a reduction of AChE in the brain. In the liver was observed oxidative stress and apoptosis. At 10 μg.L^-1 CIP, leukopenia, morphological changes, and apoptosis were presented in the blood and a reduction of AChE in the brain. Apoptosis, leukocyte infiltration, steatosis, and necrosis occurred in the liver. Even at the lowest concentration (1 μg.L^-1), adverse effects such as erythrocyte and liver genotoxicity, hepatocyte apoptosis, oxidative stress, and a decrease in somatic indexes were observed. The results showed the importance of monitoring CIP concentrations in the aquatic environment that cause sublethal effects on fish.

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

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

Neuroactive pharmaceuticals in estuaries: Occurrence and tissue-specific bioaccumulation in multiple fish species

Contamination of surface waters by pharmaceuticals is an emerging problem globally. This is because the increased access and use of pharmaceuticals by a growing world population lead to environmental contamination, threatening non-target species in their natural environment. Of particular concern are neuroactive pharmaceuticals, which are known to bioaccumulate in fish and impact a variety of individual processes such as fish reproduction or behaviour, which can have ecological impacts and compromise fish populations. In this work, we investigate the occurrence and bioaccumulation of 33 neuroactive pharmaceuticals in brain, muscle and liver tissues of multiple fish species collected in four different estuaries (Douro, Tejo, Sado and Mira). In total, 28 neuroactive pharmaceuticals were detected in water and 13 in fish tissues, with individual pharmaceuticals reaching maximum concentrations of 1590 ng/L and 207 ng/g ww, respectively. The neuroactive pharmaceuticals with the highest levels and highest frequency of detection in the water samples were psychostimulants, antidepressants, opioids and anxiolytics, whereas in fish tissues, antiepileptics, psychostimulants, anxiolytics and antidepressants showed highest concentrations. Bioaccumulation was ubiquitous, occurring in all seven estuarine and marine fish species. Notably, neuroactive compounds were detected in every water and fish brain samples, and in 95% of fish liver and muscle tissues. Despite variations in pharmaceutical occurrence among estuaries, bioaccumulation patterns were consistent among estuarine systems, with generally higher bioaccumulation in fish brain followed by liver and muscle. Moreover, no link between bioaccumulation and compounds' lipophilicity, species habitat use patterns or trophic levels was observed. Overall, this work highlights the occurrence of a highly diverse suite of neuroactive pharmaceuticals and their pervasiveness in waters and fish from estuarine systems with contrasting hydromorphology and urban development and emphasizes the urgent need for toxicity assessment of these compounds in natural ecosystems, linked to internalized body concentration in non-target species.

The use of Gammarus pulex as a model organism for ecotoxicological assessment of ibuprofen and propranolol at environmental relevant concentrations

The aim of this study is to assess the toxicity of ibuprofen (IBU) and propranolol (PRO) drugs usingGammarus pulex as a model organism. Firstly, the 96 h LC₅₀ values of IBU and PRO were determined and then three sublethal concentrations of the drugs were exposed to G. pulex. The activities of superoxide dismutase (SOD), catalase (CAT) and acetylcholinesterase (AChE) were evaluated. SOD activity decreased in G. pulex exposed to IBU and PRO compared to control. In all groups exposed to IBU, CAT activity increased at different concentrations at 24 and 96 h. In the groups exposed to different PRO concentrations, CAT activities increased after 24 h compared to the control group (p < 0.05). AChE activities increased in all application groups exposed to IBU for 96 hours (p < 0.05). In conclusion, exposure to IBU and PRO resulted in increased oxidative damage. PRO has been found to cause neurotoxicity.

Will extreme weather events influence the toxic impacts of caffeine in coastal systems? Comparison between two widely used bioindicator species

In the recent years, marine heatwaves (MHWs) have caused devastating impacts on marine life. The understanding of the combined effects of these extreme events and anthropogenic pollution is a vital challenge. In particular, the combined effect of MHWs on the toxicity of pharmaceuticals to aquatic life remains unclear. To contribute to these issues, the main goal of the present investigation was to evaluate how MHWs may increase caffeine (CAF) toxicity on the clam Ruditapes philippinarum and the mussel Mytilus galloprovincialis. Bioaccumulation levels and changes on oxidative stress, metabolic capacity and neurotoxic status related biomarkers were investigated. The obtained results revealed the absence of CAF accumulation in both species. However, the used contaminant generated in both bivalve species alteration on neurotransmission, detoxification mechanisms induction as well as cellular damage. The increase of antioxidant defence mechanisms was complemented by an increase of metabolic activity and decrease of energy reserves. The obtained results seemed magnified under a simulated MHWs, suggesting to a climate-induced toxicant sensitivities' response. On this perspective, understanding of how toxicological mechanisms interact with climate-induced stressors will provide a solid platform to improve effect assessments for both humans and wildlife.

Occurrence and ecotoxicity of sulfonamides in the aquatic environment: A review

Rapid population growth and increasing demand for animal protein food have led to a continuous increase in global utilization of antibiotic. Sulfonamides (SAs) are ubiquitous in aquatic environments and pose an ecological risk owing to their large consumption and strong environmental persistence. Hence, this review focuses on the recent publications on 12 different SAs and provides a detailed summary of selected antibiotic concentrations in various water systems. We evaluated the ecotoxicity of SAs on organisms at different trophic level organisms and the environmental risks regarding aquatic systems. The results indicated that SA antibiotics were ubiquitous in aquatic environments at concentrations ranging from ng/L to μg/L. According to the data using standard ecotoxicity bioassays, algae were the most susceptible aquatic organisms for selected antibiotics, followed by crustaceans and fish. The risk data suggested that some antibiotics, such as sulfadiazine (SDZ), sulfamethoxazole (SMX), and sulfamethazine (SMZ) pose a great risk to the aquatic system. Based on the present review, it is necessary to strengthen the research into their ecotoxicity to marine systems and the chronic toxicity of antibiotic mixtures.

A multi-biomarker approach for the early assessment of the toxicity of hospital wastewater using the freshwater organism Daphnia magna

Hospital wastewater (HWW) contains different hazardous substances resulting from a combination of medical and non-medical activities of hospitals, including pharmaceutical residues. These substances may represent a threat to the aquatic environment if they do not follow specific treatment processes. Therefore, we aimed to investigate the effects of the untreated effluent collected from a general hospital in Mahdia City (Tunisia) on neonatal stages of the freshwater crustacean Daphnia magna. Test organisms were exposed to three proportions (3.12%, 6.25%, and 12.5% v/v) of HWW. After 48 h of exposure, a battery of biomarkers was measured, including the quantification of antioxidant enzymes [catalase (CAT) and total and selenium-dependent glutathione peroxidase (total GPx; Se-GPx)], phase II biotransformation isoenzymes glutathione-S-transferases (GSTs), cyclooxygenases (COX) involved in the regulation of the inflammatory process, and total cholinesterases (ChEs) activities. Lipid peroxidation (LPO) was measured to estimate oxidative damage. The here-obtained results showed significant decreases of CAT and GSTs activities and also on LPO content in daphnids, whereas Se-GPx activity was significantly increased in a dose-dependent manner. Impairment of cholinesterasic and COX activities were also observed, with a significant decrease of ChEs and an increase of COX enzymatic activities. Considering these findings, HWW was capable of inducing an imbalance of the antioxidant defense system, but without resulting in oxidative damage in test organisms, suggesting that peroxidases and alternative detoxifying pathways were able to prevent the oxidant potential of several drugs, which were found in the tested effluents. In general, this study demonstrated the toxicity of hospital effluents, measured in terms of the potential impairment of key pathways, namely neurotransmission, antioxidant defense, and inflammatory homeostasis of crustaceans.

Pharmaceuticals, hormones, plasticizers, and pesticides in drinking water

Humans are exposed to endocrine disrupting compounds (EDCs) in tap water via drinking water. Currently, most of the analytical methods used to assess a long list of EDCs in drinking water have been made available only for a single group of EDCs and their metabolites, in contrast with other environmental matrices (e.g., surface water, sediments, and biota) for which more robust methods have been developed that allow detection of multiple groups. This study reveals an analytical method of one-step solid phase extraction, incorporated together with liquid chromatography-tandem mass spectrometry for the quantification of multiclass EDCs (i.e., pharmaceuticals, hormones, plasticizers, and pesticides) in drinking water. Fifteen multiclass EDCs significantly varied in amount between field samples (p < 0.05), with a maximum concentration of 17.63 ng/L observed. Daily exposure via drinking water is unlikely to pose a health risk (risk quotient < 1). This method serves as an analytical protocol for tracing multiclass EDC contamination in tap water as part of a multibarrier approach to ensure safe drinking water for good health and well-being. It represents a simpler one-step alternative tool for drinking water analysis, thereby avoiding the time-consuming and expensive multi-extraction steps that are generally needed for analyzing multiclass EDCs.

Reproductive stimulation and energy allocation variation of BDE-47 and its derivatives on Daphnia magna

As endocrine disrupting chemical, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is widely distributed in water environment with a high detection rate. 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47) and 6-methoxy-2,2',4,4'-tetrabromodiphenyl ether (6-MeO-BDE-47) are two main derivatives of BDE-47. To explore the aquatic risk of BDE-47 and its derivatives, the effects of them and their ternary mixture on the reproduction, growth, energy allocation, and neurological and antioxidant responses of Daphnia magna were monitoring during different exposure periods, i.e., daphnids exposed to compounds for 21 days or pre-exposed to compounds for 14 days and then recovered 7 days in clean water. In general, in 21-day test, reproductive parameters of exposed daphnids were significantly stimulated, and the growth and enzymatic activities of super oxidase dimutase (SOD), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) were significantly depressed by the single- or mixture compounds. In (14 + 7)-day test, the levels of body length, number of living offspring per female and the enzyme activities recovered to some degree. However, after 7 days of recovery in pollution free medium, the reproductive parameters and enzymatic activities of D. magna were unable to restore control values. These results showed that D. magna has a tendency that the energy allocated to reproduction was greater than that to grow after exposure. The energy distribution of D. magna occurred autonomously after being exposed, which can make it better adapt to environmental changes. Moreover, based on the behavioral and enzymology indicators of D. magna, the spider chart's application in the characteristic analysis of function indicators of D. magna implied that SOD, GPx and AChE could become sensitive biomarkers for different exposure periods. Those findings enable us to better understand BDE-47 and metabolites, and are conducive to better take measures to solve the pressure it brings.

Neuromotor activity inhibition in zebrafish early-life stages after exposure to environmental relevant concentrations of caffeine

Caffeine (CAF), a neuroactive compound, has been found in surface waters at concentrations ranging from few nanograms up to micrograms and may induce adverse effects in aquatic vertebrates. Thus, the aim of this study was to evaluate the potential of CAF in affecting fish early-life stages in a wide concentration range, including occurring levels in surface waters. Specimens of zebrafish in early-life stages were exposed to CAF for 168 h and survival, developmental alterations, locomotor activity and acetylcholinesterase activity were evaluated. CAF induced mortality in embryos unable to hatch or in larvae after hatching (LC₅₀ - 168 h = 283.2 mg/L). Tail deformities were observed in organisms exposed to concentrations ≥ 40 mg/L, while edemas were found at concentrations of 100 mg/L. CAF also decreased the total swimming time and distance moved of exposed organisms (LOEC = 0.0006 mg/L). Locomotor inhibition may be associated with an acetylcholinesterase inhibition observed at concentration ≥ 0.0088 mg/L. Therefore, the hazard of CAF for fish populations deserves further attention since unexpected effects on neuro-behavioral parameters occurs at concentrations often detected in natural aquatic ecosystems.

A review of pharmaceutical occurrence and pathways in the aquatic environment in the context of a changing climate and the COVID-19 pandemic

Active pharmaceutical ingredients (APIs) are increasingly being identified as contaminants of emerging concern (CECs). They have potentially detrimental ecological and human health impacts but most are not currently subject to environmental regulation. Addressing the life cycle of these pharmaceuticals plays a significant role in identifying the potential sources and understanding the environmental impact that pharmaceuticals may have in surface waters. The stability and biological activity of these "micro-pollutants" can lead to a pseudo persistence, with ensuing unknown chronic behavioural and health-related effects. Research that investigates pharmaceuticals predominantly focuses on their occurrence and effect within surface water environments. However, this review will help to collate this information with factors that affect their environmental concentration. This review focuses on six pharmaceuticals (clarithromycin, ciprofloxacin, sulfamethoxazole, venlafaxine, gemfibrozil and diclofenac), chosen because they are heavily consumed globally, have poor removal rates in conventional activated sludge wastewater treatment plants (CAS WWTPs), and are persistent in the aquatic environment. Furthermore, these pharmaceuticals are included in numerous published prioritisation studies and/or are on the Water Framework Directive (WFD) "Watch List" or are candidates for the updated Watch List (WL). This review investigates the concentrations seen in European Union (EU) surface waters and examines factors that influence final concentrations prior to release, thus giving a holistic overview on the source of pharmaceutical surface water pollution. A period of 10 years is covered by this review, which includes research from 2009-2020 examining over 100 published studies, and highlighting that pharmaceuticals can pose a severe risk to surface water environments, with each stage of the lifecycle of the pharmaceutical determining its concentration. This review additionally highlights the necessity to improve education surrounding appropriate use, disposal and waste management of pharmaceuticals, while implementing a source directed and end of pipe approach to reduce pharmaceutical occurrence in surface waters.

Tap water contamination: Multiclass endocrine disrupting compounds in different housing types in an urban settlement

Contamination of endocrine disrupting compounds (EDCs) in tap water is an emerging global issue, and there are abundant influencing factors that have an ambivalent effect on their transportation and fate. Different housing types vary in terms of water distribution system operation and design, water consumption choices, and other hydraulic factors, which potentially affect the dynamics, loadings, and partitioning of pollutants in tap water. Thus, this study analyzed 18 multiclass EDCs in tap water from different housing types (i.e., landed and high-rise) and the associated health risks. Sample analyses revealed the presence of 16 EDCs, namely hormones (5), pharmaceuticals (8), a pesticide (1), and plasticizers (2) in tap water, with the prevalent occurrence of bisphenol A up to 66.40 ng/L in high-rise housing. The presence of caffeine and sulfamethoxazole distribution in tap water was significantly different between landed and high-rise housings (t(152) = -2.298, p = 0.023 and t(109) = 2.135, p = 0.035). Moreover, the salinity and conductivity of tap water in high-rise housings were significantly higher compared to those in landed housings (t(122) = 2.411, p = 0.017 and t(94) = 2.997, p = 0.003, respectively). Furthermore, there were no potential health risks of EDCs (risk quotient < 1) estimated in different age groups via drinking water intake. However, EDC variation in different housing types requires simulation of the occurrence, transport, and fate of EDCs in the distribution system and investigation of the underlying factors for effective mitigation, prevention, and intervention.

Biomarker Responses of the Clam Ruditapes decussatus Exposed to a Complex Mixture of Environmental Stressors under the Influence of an Urban Wastewater-Treatment Plant

To evaluate the potential impact of an urban wastewater-treatment plant on Ria Formosa coastal lagoon, a sentinel species, the clam Ruditapes decussatus, was exposed along a gradient of the effluent's dispersal for 1 mo. Three exposure sites were selected to study the responses of 3 biomarkers: electron transport system, acetylcholinesterase, and lipid peroxidation. As complementary data, morphometric measurements, condition index, and lipid and protein content were considered together with in situ physicochemical characterization of the sites (temperature, salinity, pH, and dissolved oxygen). Electron transport system activity levels were between 35.7 and 50.5 nmol O₂ /min g protein, acetylcholinesterase activity levels ranged from 2.6 to 3.8 nmol/min g protein, and lipid peroxidation ranged from 174.7 to 246.4 nmol malondialdehyde/g protein. The exposure sites shaped the response not only of biomarkers but also of "health" parameters (protein, lipids, and condition index). Lipid peroxidation was the most responsive biomarker also associated with electron transport system, especially at the closest site to the urban wastewater-treatment plant. Because of the presence of complex mixtures of contaminants in urban effluents, biomarker responses can provide valuable information in environmental assessment. However, it is vital to identify all biological and ecological factors induced by the natural life cycle of clams. Abiotic factors can mask or overlap the response of biomarkers and should be considered in a multibiomarker approach. Environ Toxicol Chem 2021;40:272-283. © 2020 SETAC.

A review of the toxicity in fish exposed to antibiotics

Antibiotics are widely used in the treatment of human and veterinary diseases and are being used worldwide in the agriculture industry to promote livestock growth. However, a variety of antibiotics that are found in aquatic environments are toxic to aquatic organisms. Antibiotics are not completely removed by wastewater treatment plants and are therefore released into aquatic environments, which raises concern about the destruction of the ecosystem owing to their non-target effects. Since antibiotics are designed to be persistent and work steadily in the body, their chronic toxicity effects have been studied in aquatic microorganisms. However, research on the toxicity of antibiotics in fish at the top of the aquatic food chain is relatively poor. This paper summarizes the current understanding of the reported toxicity studies with antibiotics in fish, including zebrafish, to date. Four antibiotic types; quinolones, sulfonamides, tetracyclines, and macrolides, which are thought to be genetically toxic to fish have been reported to bioaccumulate in fish tissues, as well as in aquatic environments such as rivers and surface water. The adverse effects of these antibiotics are known to cause damage to developmental, cardiovascular, and metabolic systems, as well as in altering anti-oxidant and immune responses, in fish. Therefore, there are serious concerns about the toxicity of antibiotics in fish and further research and strategies are needed to prevent them in different regions of the world.

Occurrence of multiclass endocrine disrupting compounds in a drinking water supply system and associated risks

Contamination by endocrine disrupting compounds (EDCs) concerns the security and sustainability of a drinking water supply system and human exposure via water consumption. This study analyzed the selected EDCs in source (river water, n = 10) and supply (tap water, n = 155) points and the associated risks. A total of 14 multiclass EDCs was detected in the drinking water supply system in Malaysia. Triclosan (an antimicrobial agent) and 4-octylphenol (a plasticizer) were only detected in the tap water (up to 9.74 and 0.44 ng/L, respectively). Meanwhile, chloramphenicol and 4-nonylphenol in the system were below the method detection limits. Bisphenol A was observed to be highest in tap water at 66.40 ng/L (detection: 100%; median concentration: 0.28 ng/L). There was a significant difference in triclosan contamination between the river and tap water (p < 0.001). Overall, the life groups were estimated at no possible risk of EDCs (risk quotient < 1). Nonetheless, the results concern the transport and impact of EDCs on the drinking water supply system regarding treatment sustainability and water security. Further exploration of smart monitoring and management using Big Data and Internet of Things and the need to invent rapid, robust, sensitive, and efficient sensors is warranted.

Active pharmaceutical ingredients in Malaysian drinking water: consumption, exposure, and human health risk

Active pharmaceutical ingredients (APIs) are typical endocrine disruptors found in common pharmaceuticals and personal care products, which are frequently detected in aquatic environments, especially surface water treated for drinking. However, current treatment technologies are inefficient for removing emerging endocrine disruptors, leading to the potential contamination of tap water. This study employed an optimized analytical method comprising solid-phase extraction and liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) to detect APIs in tap water in Putrajaya, Malaysia. Several therapeutic classes of pharmaceuticals and personal care products, including anti-inflammatory drugs (dexamethasone and diclofenac), antibiotics (sulfamethoxazole and triclosan), antiepileptics (primidone), antibacterial agents (ciprofloxacin), beta-blockers (propranolol), psychoactive stimulants (caffeine), and antiparasitic drugs (diazinon), were detected in the range of < 0.03 to 21.39 ng/L, whereas chloramphenicol (an antibiotic) was below the detection limit (< 0.23 ng/L). A comparison with global data revealed the spatial variability of emerging tap water pollutants. Diclofenac accounted for the highest concentration (21.39 ng/L), followed by triclosan and ciprofloxacin (9.74 ng/L and 8.69 ng/L, respectively). Caffeine was observed in all field samples with the highest distribution at 35.32%. Caffeine and triclosan exhibited significantly different distributions in household tap water (p < 0.05). Humans are exposed to these APIs by drinking the tap water; however, the estimated risk was negligible (risk quotient < 1). APIs are useful water quality monitoring indicators for water resource conservation and water supply safety related to emerging organic contaminants; thus, API detection is important for safeguarding the environment and human health.

Endocrine disruptive action of diclofenac and caffeine on Astyanax altiparanae males (Teleostei: Characiformes: Characidae)

Diclofenac (DCF) and caffeine (CAF) are persistent pharmaceuticals that occur in mixtures in the aquatic ecosystems causing effects in the reproductive physiology of aquatic organisms. This study evaluated the physiological reproductive responses of Astyanax altiparanae males exposed to nominal concentrations of DCF (3.08 mg L^-1) and CAF (9.59 mg L^-1) separately and combined, for 96 h. The steroids profile, estrogenic biomarker vitellogenin (vtgA), testes and liver morphology, and also mortality of males were assessed. DCF and CAF degradation was 5% of the initial concentration for 24 h. The LC₅₀ of the DCF and CAF were 30.8 mg L^-1 and 95.9 mg L^-1, respectively. Males exposed to DCF and CAF exhibited a reduction of 17β-Estradiol (E₂) concentration compared to control (CTL). Similarly, testosterone (T) was also reduced in the DCF treatment, but this response was not observed in 11-Ketotestosterone (11-KT). Males exposed to DCF + CAF combined did not exhibit differences in T, E₂ and 11-KT steroids. The vtgA gene expression and the sperm concentration did not change among the treatments. Moreover, acute exposure revealed a hypertrophy of hepatocytes cells in the DCF and DCF + CAF treatments. In conclusion, DCF and CAF, isolated, exhibit an endocrine disruptive activity in A. altiparanae male, an opposite response observed with the mixture of both compounds that abolishes the endocrine disruptive effects. DCF seems to be more toxic for this species, altering also hepatocytes morphology.

Inhibition to crucial enzymes in the lethal effects of the dinoflagellate Karenia mikimotoi on the rotifer Brachionus plicatilis

Blooms of the dinoflagellate Karenia mikimotoi have cause great financial losses to the marine aquaculture industry. However, the toxicity mechanism of this species is still not fully known. In this study, we evaluated the short-term effects of K. mikimotoi on the rotifer Brachionus plicatilis by micro and sub micro observing and by measuring inhibition of crucial enzymes. Behaviour disorder, mucus production, corona and cilium damage, vesical production, and body shrinkage occurred within 1 h after rotifers were treated with K. mikimotoi at a density of 3 × 10⁴ cells/mL. Enzyme activity assays showed that K. mikimotoi at low densities significantly inhibited multiple enzymes within 3 h, and obvious density-effect trends were also observed. For instance, activity of esterase and acetylcholinesterase of rotifers significantly decreased to 94.3/83.3% and 82.8/66.9% of control treatment values in 30 and 1000 cells/mL algal treatment, respectively. Total ATPase and Na⁺-K⁺-ATPase activities of rotifers also decreased to 82.3% and 68.6% of control values in 1000 cells/mL treatment. The LDH releasement test and MDA tests showed no significant difference between algae treatment and control. It suggested that K. mikimotoi might not cause significant cytolysis and oxidative damage to rotifers, but may cause mortality by inhibiting the activity of crucial enzymes, which may lead to cell permeability disorder and body shrinkage.

Risks of caffeine residues in the environment: Necessity for a targeted ecopharmacovigilance program

Due to the huge consumption of caffeinated food, beverages and medicines around the world, caffeine has been considered as a most representative pharmaceutically active compound (PhAC) pollutant based on its high abundance in environment and its indicator property for anthropogenic inputs of PhACs to water bodies. This review analyzed the existing literature about the bioaccumulation and environmental risks of caffeine residues in non-target organisms. There are 6 studies which were published in the last 5 years have reported the distribution of caffeine in tissues of aquatic organisms including fishes, clams, macroalgae and other aquatic plants, suggesting bioaccumulation of caffeine in organisms. The maximum detected levels of caffeine residues in tissues ranged from 1.55 to 344.9 ng/g. Importantly, definitive evidences have been provided that environmentally relevant caffeine concentrations exert adverse impacts on aquatic species and terrestrial insects, which included lethality, decreasing general stress, inducing oxidative stress and lipid peroxidation, affecting energy reserves and metabolic activity, neurotoxic effects, affecting reproduction and development, etc. In view of the severity and potential adverse impacts of caffeine pollution in the environment, we proposed that caffeine should be considered as a high-priority environmentally hazardous PhAC pollutant, and it is necessary to implement an ecopharmacovigilance (EPV) program targeting caffeine to minimize its environmental load from a pharmacy perspective.

Occurrence and risk assessment of multiclass endocrine disrupting compounds in an urban tropical river and a proposed risk management and monitoring framework

Endocrine disrupting compounds (EDCs) are an emerging environmental concern and commonly occur as a mixture of compounds. The EDC mixture can be more toxic than any single compound. The present study analyses EDCs in surface water in the case of an urban tropical river, the Langat River, using the multiresidue analytical method of solid phase extraction and liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS). The Langat River is used as a drinking water source and is treated for Malaysian drinking water supply. A total of 14 EDCs i.e. five hormones, seven pharmaceuticals, one pesticide, and one plasticizer were detected. Caffeine was observed to be highest at 19.33 ng/L, followed by bisphenol A and diclofenac at 8.24 ng/L and 6.15 ng/L, respectively. Using a conservative risk quotient (RQ) method, EDCs were estimated for having negligible risks under acute and chronic exposure (RQ < 0.002 and RQ_mix < 0.003; RQ < 0.01), suggesting that there is currently an insignificant ecological risk related to these compounds in the Langat River riverine ecosystem. However, the presence of EDCs in surface water raises concerns about potential human exposure to EDCs via dietary intake i.e. food and drinking water supply. Although the ecological risks are considered negligible, these risks should not be neglected in terms of future prioritization and risk management. Improvements in water quality monitoring and risk assessment in water source protection are required to support a multibarrier approach to managing drinking water supply systems for safe water supply. The present study proposes a risk management and monitoring framework for EDCs to support the aforementioned multibarrier approach.

Bioconcentration of the antiepileptic drug carbamazepine and its physiological and biochemical effects on Daphnia magna

Owing to its persistence, carbamazepine an antiepileptic drug is regularly detected in the aquatic environment. The motive for our research was to assess the bioconcentration, physiological and biochemical effects of carbamazepine in Daphnia magna. A 48 h aqueous exposure of carbamazepine yielded bioconcentration factors of 202.56 and 19.95 in Daphnia magna for the respective nominal treatments of 5 and 100 µg/L. Apparently, the inhibition of the capability of Daphnia magna to obtain food attributable to carbamazepine exposure will reduce their fitness to reproduce as well as to grow. Also, a significant alteration in the phototactic behaviour of Daphnia magna exposed to carbamazepine is maladaptive since it will increase their chance of being preyed upon in the surface water during daylight. Again, a significant decline in the acetylcholinesterase activity observed herein brings to light the neurotoxicity of carbamazepine to Daphnia magna. Moreover, significant inhibition of the superoxide dismutase, catalase and glutathione reductase activities coupled with the simultaneous induction of the malondialdehyde content imply that carbamazepine evoked a life-threatening oxidative stress that overpowered the antioxidant defence system of Daphnia magna. These observations confirm that carbamazepine can accumulate and consequently cause negative physiological and biochemical changes to wild Daphnia magna populations.

Biomarker Effects in Carassius auratus Exposure to Ofloxacin, Sulfamethoxazole and Ibuprofen

Ofloxacin, sulfamethoxazole and ibuprofen are three commonly used drugs which can be detected in aquatic environments. To assess their ecotoxicity, the effects of these three pharmaceuticals and their mixture on AChE (acetylcholinesterase) activity in the brain, and EROD (7-ethoxyresorufin-O-deethylase) and SOD (superoxide dismutase) activities in the liver of the freshwater crucian carp Carassius auratus were tested after exposure for 1, 2, 4 and 7 days. The results showed that treatments with 0.002–0.01 mg/L ofloxacin and 0.0008–0.004 mg/L sulfamethoxazole did not significantly change AChE, EROD and SOD activities. AChE activity was significantly inhibited in response to treatment with >0.05mg/L ofloxacin and >0.02 mg/L sulfamethoxazole. All three biomarkers were induced significantly in treatments with ibuprofen and the mixture of the three pharmaceuticals at all the tested concentrations. The combined effects of ofloxacin, sulfamethoxazole and ibuprofen were compared with their isolated effects on the three biomarkers, and the results indicated that exposure to ibuprofen and the mixture at environmentally relevant concentrations could trigger adverse impacts on Carassius auratus. The hazard quotient (HQ) index also demonstrated a high risk for ibuprofen. Moreover, the present study showed that the effects of ofloxacin, sulfamethoxazole and ibuprofen might be additive on the physiological indices of Carassius auratus.

Occurrence, distribution, and ecological-health risks of selected antibiotics in coastal waters along the coastline of China

Information on ecological and health risks posed by antibiotics in coastal waters at continental or national scale is limited although antibiotics have continuously entered the natural environments due to extensive usage for human beings and animals. This study collected coastal water samples along nearly 18,000 km of coastline of China to investigate the distribution, possible sources, and potential ecological-health risks of antibiotics. Only 7 out of 13 target antibiotics were detected in coastal water samples. Total concentrations of antibiotics ranged from 389 to 3302.3 ng/L. Norfloxacin (NFC), roxithromycin (RTM), and ciprofloxacin (CFC) were the most frequently detected antibiotics, with the maximal concentrations of 1990, 1230, and 109 ng/L, respectively. Antibiotics in coastal waters might be affected by three possible factors including veterinary-drug sources, anthropogenic sources, and mixed sources. Detected NFC and sulfamethoxazole (SMX) exerted high ecological risks in the short and long terms. CFC posed moderate short-term risks but insignificant long-term risks for aquatic organisms. RTM exerted low short-term risks while it posed moderate risks in the long term. Antibiotics exerted very low cancer risks and negligible non-cancer risks for both adults and children at all sampling sites. Health risks for children posed by antibiotics were generally higher than those for adults. Antibiotics in coastal waters of China still need effective control due to potential ecological-health risks they pose.

Oxytetracycline effects in specific biochemical pathways of detoxification, neurotransmission and energy production in Oncorhynchus mykiss

Oxytetracycline (OTC) is a tetracycline antibiotic, widely used in human and veterinary medicines, including in aquaculture. Given this use, OTC has been detected in different aquatic environments. Some recent works have demonstrated unintentional biological activity of OTC in non-target aquatic organisms. This study investigated the acute and chronic effects of OTC on the physiology of the fish species Oncorhynchus mykiss (rainbow trout), namely through the quantification of the activity of enzymes involved in different biochemical pathways, such as detoxification (phase II - glutathione S-transferases - GSTs, uridine-diphosphate-glucuronosyltransferases - UGTs), neurotransmission (acetylcholinesterase - AChE) and energy production (lactate dehydrogenase - LDH). The here-obtained data demonstrated the induction of GSTs activity in gills, and inhibition of AChE activity in eyes tissue, in chronically exposed organisms, as well as alterations in LDH activity following both exposures. Considering this set of results, we can infer that OTC exposure may have induced the glutathione pathway of detoxification in gills with the involvement of GSTs, or indirectly due to the metabolites that may have been produced. In turn, these metabolites may have interfered with the mechanism of neurotransmission, also causing physiological and biochemical disturbances in rainbow trout after OTC exposure, namely disturbances in energetic metabolism. In addition, it is important to stress that such occurrences took place at low, environmentally realistic levels of OTC, suggesting that organisms exposed in the wild may be putative targets of toxic effects by commonly used drugs such as antibiotics.

Sublethal or not? Responses of multiple biomarkers in Daphnia magna to single and joint effects of BDE-47 and BDE-209

Polybrominated diphenyl ethers (PBDEs) are extremely incessant anthropogenic contaminants found in the environment, with dreadful risk to aquatic ecosystems. However, there is a limited amount of data concerning their impacts on freshwater organisms. 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) are significant components of total PBDEs in water. The sublethal effects of BDE-47, BDE-209 and their binary mixtures on the aquatic organism Daphnia magna were investigated in acute and chronic exposure experiments. Immobilization and heartbeat were studied in daphnids after 48 h of exposure. Mortality rate, breed number, Cholinesterase (ChE), Glutathione S-transferases (GST) and Catalase (CAT) activities were evaluated after 21 days of exposure. The results showed that at 100 and 200 μg/L concentration of BDE-47, immobilization rate of daphnids were inhibited by 44.0 ± 16.7% and 88.0 ± 10.9%, respectively. The binary mixture of BDE-47 and BDE-209 had uncongenial effects on immobilization of D. magna under acute toxicity test. BDE-209 significantly increased the heartbeat rate of daphnids, which increased even further when combined with BDE-47. After 21 days of exposure, daphnids exposed to single BDE-47 were physiologically altered. The combination of BDE-47 with BDE-209 significantly decreased the mortality rate of daphnids. Irrespective of the concentration, higher numbers of offsprings were produced in the mixtures compared to BDE-47 treatment alone. ChE activities significantly (p < 0.05) decreased at concentrations of 2 and 4 μg/L in single BDE-47 treatment, while GST activity significantly (p < 0.05) decreased at 0.5 μg/L. CAT activities significantly increased with BDE-47 treatments in all the tested concentrations (p < 0.05). The mixtures significantly affect ChE (p < 0.05), GST (p < 0.05) and CAT activities (p < 0.05). The results illustrated that the toxicity of the mixture of PBDE congeners exposed to aquatic organisms may have antagonistic effects. The 21 days chronic test in this study suggests that acute toxicity tests, i.e. 48-h tests, using Daphnia may lead to underestimation of risks associated with PBDEs, especially, BDE-209. Hence, there is a necessity to re-examine PBDE congeners' environmental risk in aquatic organisms.

Ecotoxicological evaluation of gilthead seabream (Sparus aurata) exposed to the antibiotic oxytetracycline using a multibiomarker approach

Oxytetracycline (OTC) is an antibiotic widely used in human and veterinary medicines. Since the primary toxicity occurs mainly at molecular/biochemical levels, the study of different biological responses corresponds to a sensitive and crucial approach. The aim of the present study was to assess the toxic effects of OTC in gilthead seabream (Sparus aurata) through the use of multibiomarkers and elucidate about the possible toxicological mechanisms involved. S. aurata were acutely (96 h: 0.04-400 μg/L) and chronically (28 days: 0.0004-4 μg/L) exposed to OTC. Detoxification, antioxidant defense, lipid peroxidation, genotoxicity, neurotransmission and energy metabolism biomarkers were evaluated. OTC impaired the detoxification pathways and caused peroxidative damage and genotoxicity. The relevance of the here-obtained data is high, since significant effects were recorded for levels already reported to occur in the wild, meaning that environmentally-exposed marine organisms (including those cultured at fish farms) are not completely exempt of risks posed by OTC.

Chronic exposure to low environmental concentrations and legal aquaculture doses of antibiotics cause systemic adverse effects in Nile tilapia and provoke differential human health risk

BACKGROUND

Antibiotics used globally to treat human and animal diseases exist ubiquitously in the environment at low doses because of misuse, overdose and poor absorption after ingestion, coupled with their high-water solubility and degradation resistance. However, the systemic chronic effects of exposure to low environmental concentrations of antibiotics (LECAs) and legal aquaculture doses of antibiotics (LADAs) in fish and their human health risk are currently unknown.

OBJECTIVE

To investigate the in vivo chronic effects of exposure to LECAs and LADAs using oxytetracycline (OTC) and sulfamethoxazole (SMZ) in Nile tilapia (Oreochromis niloticus) and their human health risk.

METHODS

Twenty O. niloticus weighing 27.73 ± 0.81 g were exposed to water containing LECAs (OTC at 420 ng/L and SMZ at 260 ng/L) and diets supplemented with LADAs (OTC 80 mg/kg/day and SMZ 100 mg/kg/day) for twelve weeks. General physiological functions, metabolic activities, intestinal and hepatic health were systemically evaluated. The possible human health risks of the consumption of the experimental Nile tilapia fillets in adults and children were assessed by using risk quotient.

RESULTS

After exposure, we observed retarded growth performance accompanied by reduced nutrients digestibility, feed efficiency, organ indices, and lipid body composition in treated fish. Antibiotics distorted intestinal morphological features subsequently induced microbiota dysbiosis and suppressed intestinal tight junction proteins. Exposure of fish to LECAs and LADAs induced oxidative stress, suppressed innate immunity, stimulated inflammatory and detoxification responses, concomitantly inhibited antioxidant capacity and caused lipid peroxidation in intestine and liver organs. Both LECAs and LADAs enhanced gluconeogenesis, inhibited lipogenesis and fatty acid beta oxidation in intestine and liver organs. The exposure of fish to LECAs and LADAs induced anaerobic glycolytic pathway and affected intestinal fat catabolism in intestine while halted aerobic glycolysis, increased hepatic fat catabolism, and induced DNA damage in liver. The hazard risk quotient in children for fish treated with OTCD was >1 indicating human health risk.

CONCLUSION

Overall, both LECAs and LADAs impair general physiological functions, nutritional metabolism, and compromise fish immune system. Consumption of fish fed with legal OTC provokes health risk in children. Global stringent prohibition policy for use of antibiotics in aquaculture production and strategies to limit their release into the environment are urgently required to protect human health.

Single and mixture toxicities of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 on the feeding activity of Daphnia magna: From behavior assessment to neurotoxicity

Although 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47), 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47) and 6-methoxy-2,2',4,4'-tetrabromodiphenyl ether (6-MeO-BDE-47) clearly disrupt the endocrine system, current knowledge of their single and/or mixture toxicities on other behaviors of aquatic organisms remains limited. In the present study, Daphnia magna was used to investigate the single and mixture toxicities of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 as measured by inhibition of feeding during exposure and post-exposure periods. Additionally, the biochemical performance, i.e., the activities of super oxidase dismutase (SOD), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) of the test organism was studied to investigate the potential mechanisms of the toxicity of the target compounds. The three target compounds produced an obvious depressive effect on feeding behavior during the exposure period, and the effect increased with increasing concentrations. D. magna was most sensitive to 6-OH-BDE-47. The toxicity of the ternary mixture showed an obvious concentration-dependent effect, whereas the binary mixture toxicity showed the characteristics of hormesis. During the post-exposure period, overcompensation occurred, indicating a short-term effect of the target compounds on D. magna. Additionally, significant changes occurred in neurological responses, indicating that these compounds might have neurobehavioral toxicity in D. magna. The decrease in oxidative stress enzymes (SOD and GPx) indicated that the antioxidant response of D. magna was destroyed.

Evaluation of caffeine effects on biochemical and genotoxic biomarkers in the neotropical freshwater teleost Prochilodus lineatus

Caffeine is often found in aquatic environments, leading to concerns regarding its adverse consequences for aquatic biota. Biochemical and genotoxic biomarkers were analysed in juveniles of Prochilodus lineatus to evaluate the effects of caffeine. Fish were exposed to caffeine (0.3, 3 and 30 μg L^-1) for either 24 h or 168 h. Longer exposure to caffeine resulted in a significant reduction in the activity of the phase I biotransformation enzyme ethoxyresorufin-O-deethylase (EROD) in the brain but a significant increase in the liver. Changes in glutathione content (GSH), glutathione S-transferase (GST) activity, and lipid peroxidation were not found in the liver and brain of fish exposed to caffeine. DNA damage in erythrocytes were also not found. These results show that caffeine may interfere with the biotransformation mechanism of P. lineatus after 168 h exposure, but it does not generate sufficient changes to trigger a state of oxidative stress.

In vitro effects of diosmin, naringenin, quercetin and indole-3-carbinol on fish hepatic CYP1A1 in the presence of clotrimazole and dexamethasone

Phytochemicals are widely present in fruits, vegetables and other plants and have great health benefits owing to their antioxidant properties. They are naturally found in the aquatic environment as well as discharged from sewage treatment plants after their large consumption. Little is known about their impact on fish; particularly in light of their interactions with pharmaceuticals. Therefore, this study was designed to determine the effects of diosmin, naringenin, quercetin and idole-3-carbinol on CYP1A-dependent 7-ethoxyresorufin-O-deethylase (EROD) activity on rainbow trout hepatic microsomes in the presence of two pharmaceuticals: clotrimazole and dexamethasone. The interactions between the phytochemicals and pharmaceuticals used in this study were determined using a combination index. Hepatic microsomes were exposed to two concentrations (1-or 50 μM) of phytochemicals and pharmaceuticals separately and in combinations. Singly, clotrimazole inhibited EROD activity 40% and 90% of control, while dexamethasone did not. Naringenin and diosmin inhibited EROD activity alone up to 90% and 55% respectively, but activities were further inhibited in the presence of either pharmaceutical. The preliminary study of combinations of clotrimazole with phytochemicals primarily showed synergistic effects. While EROD activity was not inhibited in the presence of quercetin or indole-3-carbinol, significant and synergistic inhibition was detected when either of these was combined with clotrimazole or dexamethasone.

Interaction of erythromycin and ketoconazole on the neurological, biochemical and behavioral responses in crucian carp

The presence of pharmaceuticals in the aquatic environment has received great attention due to their potential impacts on public health. The single, as well as the combined toxicities of erythromycin (ERY) and ketoconazole (KCZ) on the bioaccumulation, biochemical and behavioral responses, were examined in crucian carp. This study focused on the uptake of contaminants, acetylcholinesterase (AChE) activity in the brain, swimming and shoaling behavior of fish. After 14days of binary exposure, the addition of KCZ at nominal concentrations of 0.2, 2 and 20μg/L significantly increased the accumulation of ERY in the brain of the fish and the bioconcentration factor of 2.08 was 2.6-fold higher than that calculated from the ERY-alone exposure. The brain AChE activity was significantly inhibited by ERY and KCZ with a significant correlation with respect to the accumulative concentration of the contaminants. The inhibition rates of swimming activity to KCZ were increased with a corresponding increase in the exposure concentration of KCZ in the single exposure. However, this manner was altered by the combined exposure. In addition, shoaling was significantly enhanced by KCZ-alone exposure, which was significantly correlated with the swimming activity. This study indicates that the mixture of the contaminants may cause endocrine disrupting effects and behavior modification especially in fish with known ecological and evolutionary consequences.

The impact assessment of anticancer drug imatinib on the feeding behavior of rotifers with an integrated perspective: Exposure, post-exposure and re-exposure

The anticancer drugs are getting increasing attention as an emerging contaminant in the aquatic environments. In the present study, feeding behavior of the rotifer Brachionus calyciflorus under the impact of anticancer drug imatinib was evaluated. Traditional toxicological studies usually focus on dose-effect relationship at a given exposure time, while ignore the possible impact after the exposure. Thus, how the impact varied in the post-exposure and re-exposure was also considered in the present study. The feeding depression of the rotifers was attributed to the increased concentration of imatinib. Although the filtration and ingestion rate of the rotifers recovered to a certain extent after the exposure, the significant feeding inhibition still persisted even if the exposure was ended. In the re-exposure period, the feeding behavior was less depressed than those of the exposure period, which implied that rotifers might develop a tolerance to the same toxics. The activities of acetylcholine esterase (AchE) and the levels of reactive oxygen species (ROS) in rotifers were also detected. Imatinib inhibited the activities of AchE in the exposure and re-exposure while ROS levels increased significantly in the re-exposure period. Our present study provided an integrated assessment the potential environmental risks of imatinib at a new perspective.

Induction of EROD and BFCOD activities in tissues of barbel (Barbus callensis) from a water reservoir in Algeria

EROD and BFCOD activities were measured in liver and gills of barbel (Barbus callensis, a native North African species) captured at Beni Haroun lake, the most important water reservoir in Algeria. This lake receives wastewater from different origins. Thus, we assessed the level of pollution through the induction of detoxification activities in tissues of barbel, evaluating simultaneously the suitability of this species to be used as a sentinel. Fish were collected between March 2015 and January 2016 at three locations taking into account the pollution sources and accessibility. In liver, EROD and BFCOD showed the highest induction in October specially in the location of the dam that received pollutants. In gills, only EROD, but not BFCOD, activity was detected. Maximal EROD induction was noted in samples from January. Fish cell lines (RTG-2 and PLHC-1) were exposed to sediments extracts collected at Beni Haroun lake and enzyme activities (EROD and BFCOD, respectively) were measured. Sediment extracts did not induce BFCOD activity. The EROD induction observed in RTG-2 cells was in line with the results observed in fish tissues. Our results suggest that the lake is at risk from pollution and that Barbus callensis is a good sentinel species.

Modulation of erythromycin-induced biochemical responses in crucian carp by ketoconazole

The individual and combined biochemical responses of erythromycin and ketoconazole have been examined in an organism representative of the aquatic environment, crucian carp (Carassius auratus). The possible interactions between erythromycin and ketoconazole were investigated on the bioaccumulation and the expression of biotransformation enzymes 7-ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST), and an antioxidant defense enzyme superoxide dismutase (SOD) in fish tissues. After 14 days of combined exposure (erythromycin + ketoconazole), the addition of ketoconazole at nominal concentrations of 0.2, 2, and 20 μg/L significantly increased the accumulation of erythromycin in fish bile; however, elevated erythromycin accumulation levels were not observed in the other test tissues. The inductions of EROD and SOD activity to erythromycin were inhibited by the combined exposure of ketoconazole in most cases; however, the GST activity returned to normal with exposure time and concentration of combined administration. From the tested pharmaceutical mixtures, it indicated that certain specific combinations may pose some perturbations in biochemical responses in fish and also provide a better understanding of the effects of toxic mixtures.

Do pharmaceuticals reach and affect the aquatic ecosystems in Brazil? A critical review of current studies in a developing country

Pharmaceutical residues are not completely removed in wastewater treatment plants (WWTPs) becoming contaminants in aquatic ecosystems. Thereby, it is important to investigate their concentrations in the environment and the possible consequences of their occurrence, including for human health. Here, we briefly reviewed the paths of pharmaceuticals to reach the environment, their behavior and fate in the environment, and the possible consequences of their occurrence. Moreover, we synthetized all the studies about the detection of pharmaceuticals in Brazilian water bodies and the available ecotoxicological knowledge on their effects. In this study, when we compare the data found on these compounds worldwide, we observed that Brazilian surface waters present considerable concentrations of 17α-ethinylestradiol, 17β-estradiol, and caffeine. In general, concentrations found in aquatic systems worldwide seems to be low; however, ecotoxicological tests showed that even these low concentrations can cause sublethal effects in biota. The knowledge about the effects of continuous exposure and mixtures is sparse. In summary, new research is urgently required about the effects of these compounds in biota-including long-term exposition and mixture tests-and on specific technologies to remove these compounds in water bodies and WWTPs, besides the introduction of new policies for pharmaceutical use.

Bioconcentration, metabolism, and biomarker responses in marine medaka (Oryzias melastigma) exposed to sulfamethazine

The antibiotic sulfamethazine (SM₂) is commonly used in agriculture and livestock for its broad-spectrum antibacterial properties. Due to its widespread application, SM₂ is frequently detected in surface water and sediments. The objective of this study was to investigate the bioconcentration, distribution and biomarker responses of SM₂ and its main metabolite, acetylated sulfamethazine (N-SM₂) in medaka (Oryzias melastigma). Two treated groups of medaka were exposed to concentrations of 40μg/L and 200μg/L of SM₂ for 24h to simulate the habitual use of those antibiotics in aquiculture activities. SM₂ and its main metabolite, N-SM₂, were measured in several tissues during the 24h uptake period by UPLC/MS/MS. The bile exhibited the highest SM₂ concentration followed by the liver, gonad, gills, and muscle and the bioconcenration factor (BCF) was 10.69-42.95 in female fish and 2.78-145.36 in male fish. N-SM₂ showed a different distribution pattern from the parent compound, accumulating mainly in the gonad, and its BCF was much higher in the male group. Gender-related differences were also observed in the bioconcentration, transform rate and biomarkers of SM₂. Biomarkers (SOD, CAT) in the liver changed significantly after 2, 12, and 24h of exposure (P<0.05), and presented a double-peak phenomenon. These results indicated that SM₂ can be absorbed and metabolized through multiple routes by fish in a short time. Interactions between biological systems and SM₂ or its metabolites may induce biochemical disturbances in fish.

Use of an integrated biomarker-based strategy to evaluate physiological stress responses induced by environmental concentrations of caffeine in the Mediterranean mussel Mytilus galloprovincialis

The occurrence of caffeine (CF), a biologically active drug, has widely been documented in coastal waters, and whether its environmental concentrations do represent a threat for marine organisms is unclear. The present study aimed at assessing sub-lethal effects induced by a 7-day exposure to environmentally relevant concentrations of CF (5, 50 and 500ng/L) in the Mediterranean mussel, Mytilus galloprovincialis. CF in water and mussel tissues, and a battery of biomarkers, including lysosomal parameters of general stress, oxidative stress responses and endpoints of neurological and genetic damages, were evaluated and tested for significance vs controls (p<0.05). CF exposure triggered a significant decrease of lysosomal membrane stability in both haemocytes and digestive gland (at 50 and 500ng/L CF) and a significant increase of lysosomal content of neutral lipids (at 500ng/L CF), indicating the onset of a stress syndrome. No effects were noted on lipid peroxidation parameters, such as malondialdehyde and lipofuscin content. The activity of the antioxidant enzymes glutathione S-transferase (GST) and catalase was unmodified in gills, while a significant increase of GST activity was observed in digestive gland (at 5 and 500ng/L CF), suggesting the occurrence of GST-mediated phase II detoxifying processes. CF did not induce geno/neurotoxicity, as shown by the lack of effects on primary DNA damages and acetylcholinesterase activity. In line with its high hydrophilicity, CF did not bioaccumulate in mussel tissues. Data were integrated using the Mussel Expert System, which assigned a low stress level to mussels exposed to 500ng/L CF, whereas no alterations of animal health status were highlighted at lower dosages. This study revealed a low profile of toxicity for environmental concentrations of CF, and confirmed the suitability of an integrated biomarker-based approach to provide a comprehensive picture of the degree of stress induced by emerging contaminants in marine invertebrates.

Long-term effects of antibiotics, norfloxacin, and sulfamethoxazole, in a partial life-cycle study with zebrafish (Danio rerio): effects on growth, development, and reproduction

A partial life-cycle study with zebrafish (Danio rerio) was conducted to evaluate the long-term effects of antibiotics, norfloxacin (NOR) and sulfamethoxazole (SMX). A series of bio-endpoints correlated to the growth, development, and reproduction was assessed. The results showed that the body weight and the condition factor were depressed by SMX at 200 μg/L during the growth period. Meanwhile, the activities of metabolic enzyme (ethoxyresorufin O-deethylase, EROD) and antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT) were stimulated in all cases. The consequences of parental exposure to antibiotics for the next generation were also examined. The egg production of parents were depressed by the 200 μg/L NOR and SMX alone or in combination. Similarly, decreased hatching, survival, and enhanced development abnormality of the next generation also occurred after parental exposure to SMX at the highest concentration. The heartbeat however was not altered in all cases. Furthermore, there was no significant difference in the bio-endpoints between the combined and individual treatment in most cases, with the exception of lower EROD activity and egg production in the co-treatment. The results suggest that long-term exposure to NOR and SMX at environmentally relevant concentrations, individually and in a mixture, may not significantly pose a threat to the growth, development, and reproduction of zebrafish, and an adverse effect may be expected at high concentration.

Responses of cytochrome P450, GST, and MXR in the mollusk Corbicula fluminea to the exposure to hospital wastewater effluents

Pharmaceutical products are a major group of chemical compounds that are continuously released into the environment. The primary pathway of pharmaceuticals to the aquatic environment is the discharge of wastewater effluents. The Psychiatric hospital of Montpon (Dordogne, France) operates with its wastewater treatment plant. We first evaluated the presence and concentrations of 27 pharmaceuticals compounds in these effluents. All of the 27 compounds were detected in these wastewater effluents at concentrations ranging between 37,500 ng L(-1) (paracetamol) and 150 ng L(-1) (citalopram). The aim of the study was then to evaluate the exposure effects of the effluents on cytochrome P450, GST, and MXR responses in Corbicula fluminea gills and digestive glands. Experiments on clams exposed during 1, 3, 7 14, and 21 days revealed a strong and continuous overexpression of mdr1 (multidrug resistant 1) gene expression in gills and transitory variations in pi-gst expression and GST activity. EROD activity increased also transitory after 1 day in the digestive gland of exposed clams. These results indicated that in the effluent, some molecules have undergone metabolism of phase 1 and/or phase 2.

Recognizing the importance of exposure-dose-response dynamics for ecotoxicity assessment: nitrofurazone-induced antioxidase activity and mRNA expression in model protozoan Euplotes vannus

The equivocality of dose-response relationships has, in practice, hampered the application of biomarkers as a means to evaluate environmental risk, yet this important issue has not yet been fully recognized or explored. This paper evaluates the potential of antioxidant enzymes in the ciliated protozoan Euplotes vannus for use as biomarkers. Dose-response dynamics, together with both the enzyme activity and the gene expression of the antioxidant enzymes, superoxide dismutase, and glutathione peroxidase, were investigated when E. vannus were exposed to graded doses of nitrofurazone for several discrete durations. Mathematical models were explored to characterize the dose-response profiles and, specifically, to identify any equivocality in terms of endpoint. Significant differences were found in both enzyme activity and messenger RNA (mRNA) expression in the E. vannus treated with nitrofurazone, and the interactions between exposure dosage and duration were significant. Correlations between enzyme activity, mRNA expression, and nitrofurazone dose varied with exposure duration. Particularly, the dose-responses showed different dynamics depending on either endpoint or exposure duration. Our findings suggest that both the enzyme activity and the gene expression of the tested antioxidant enzymes can be used as biomarkers for ecotoxicological assessment on the premise of ascertaining appropriate dosage scope, exposure duration, endpoint, etc., which can be achieved by using dose-response dynamics.

Time-dependent bidirectional effects of chronic caffeine on functional recovery of the dorsal light reflex after hemilabyrinthectomy in the goldfish Carassius auratus

Caffeine works through a variety of complex mechanisms to exert an often bidirectional set of functional and structural neurological changes in vertebrates. We investigated the effects of chronic caffeine exposure on functional recovery of the dorsal light reflex (DLR) in hemilabyrinthectomized common goldfish, Carassius auratus. In this lesion model, the unilateral removal of the vestibular organs results in a temporary loss of gravitationally modulated postural control which is quantifiable via the DLR. We compared the functional recovery over 24 days of post-surgery goldfish continuously held in a caffeine solution of 2.5mg/L (n=10), 5.0mg/L (n=10), 10.0mg/L (n=11), or 0.0mg/L control (n=9). Comparison to a sham surgery group (n=11) indicated statistically significant changes in the DLR of all hemilabyrinthectomized fish on day 1. The control group recovered over the study period and approached, but did not reach sham surgery DLR. Although the caffeine-treated fishes appeared to initiate some postural recovery within the first 2 weeks, beginning on day 10, all caffeine groups diverged from the control group with a deterioration of postural control. All three caffeine groups were significantly deficient in comparison with the control on days 10-24. These results suggest that caffeine exposure can at first be benign, but that high dosage or prolonged exposure hinders functional recovery.

Disability adjusted life year (DALY): a useful tool for quantitative assessment of environmental pollution

Disability adjusted life year (DALY) has been widely used since 1990s for evaluating global and/or regional burden of diseases. As many environmental pollutants are hazardous to human health, DALY is also recognized as an indicator to quantify the health impact of environmental pollution related to disease burden. Based on literature reviews, this article aims to give an overview of the applicable methodologies and research directions for using DALY as a tool for quantitative assessment of environmental pollution. With an introduction of the methodological framework of DALY, the requirements on data collection and manipulation for quantifying disease burdens are summarized. Regarding environmental pollutants hazardous to human beings, health effect/risk evaluation is indispensable for transforming pollution data into disease data through exposure and dose-response analyses which need careful selection of models and determination of parameters. Following the methodological discussions, real cases are analyzed with attention paid to chemical pollutants and pathogens usually encountered in environmental pollution. It can be seen from existing studies that DALY is advantageous over conventional environmental impact assessment for quantification and comparison of the risks resulted from environmental pollution. However, further studies are still required to standardize the methods of health effect evaluation regarding varied pollutants under varied circumstances before DALY calculation.