Integrated biomarker response index to assess toxic effects of environmentally relevant concentrations of paracetamol in a neotropical catfish (Rhamdia quelen)

Assessing the impact of COVID-19 era drug combinations on hepatic functionality: A thorough investigation in adult Danio rerio

Current and thorough information on the ecotoxicological consequences of pharmaceuticals is accessible globally. However, there remains a substantial gap in knowledge concerning the potentially toxic effects of COVID-19 used drugs, individually and combined, on aquatic organisms. Given the factors above, our investigation assumes pivotal importance in elucidating whether or not paracetamol, dexamethasone, metformin, and their tertiary mixtures might prompt histological impairment, oxidative stress, and apoptosis in the liver of zebrafish. The findings indicated that all treatments, except paracetamol, augmented the antioxidant activity of superoxide dismutase (SOD) and catalase (CAD), along with elevating the levels of oxidative biomarkers such as lipid peroxidation (LPX), hydroperoxides (HPC), and protein carbonyl content (PCC). Paracetamol prompted a reduction in the activities SOD and CAT and exhibited the most pronounced toxic response when compared to the other treatments. The gene expression patterns paralleled those of oxidative stress, with all treatments demonstrating overexpression of bax, bcl2, and p53. The above suggested a probable apoptotic response in the liver of the fish. Nevertheless, our histological examinations revealed that none of the treatments induced an apoptotic or inflammatory response in the hepatocytes. Instead, the observed tissue alterations encompassed leukocyte infiltration, sinusoidal dilatation, pyknosis, fatty degeneration, diffuse congestion, and vacuolization. In summary, the hepatic toxicity elicited by COVID-19 drugs in zebrafish was less pronounced than anticipated. This attenuation could be attributed to metformin's antioxidant and hormetic effects.

Toxic effects and comparison of common amino antioxidants (AAOs) in the environment on zebrafish: A comprehensive analysis based on cells, embryos, and adult fish

The ubiquity of amino antioxidants (AAOs) in the environment has attracted increasing attention, given their potential toxicity. This investigation represents a pioneering effort, systematically scrutinizing the toxicological effects of four distinct AAOs across the developmental spectrum of zebrafish, encompassing embryonic, larvae, and adult stages. The results indicate that four types of AAO exhibit varying degrees of cell proliferation toxicity. Although environmentally relevant concentrations of AAOs exhibit a comparatively circumscribed impact on zebrafish embryo development, heightened concentrations (300 μg/L) of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD) distinctly evoke developmental toxicity. Behavioral analysis results indicate that at concentrations of 20 and 300 μg/L, the majority of AAOs significantly reduced the swimming speed and activity of larvae. Moreover, each AAO triggers the generation of reactive oxygen species (ROS) in larvae, instigating diverse levels of oxidative stress. The study delineates parallel toxicological patterns in zebrafish exposed to 300 μg/L of 6PPD and IPPD, thereby establishing a comparable toxicity profile. The comprehensive toxicity effects among the four AAOs is as follows: IPPD >6PPD > N-Phenyl-1-naphthylamine (PANA) > diphenylamine (DPA). These findings not only enrich our comprehension of the potential hazards associated with AAOs but also provide data support for structure-based toxicity prediction models.

Physiological strategies of acute thermal conditions of Rhamdia voulezi collected in the Iguaçu river watershed, Paraná, Brazil: biochemical markers of metabolic and oxidative stress

Thermal pollution creates substantial challenges that alter energy demand and produce reactive oxygen species that damage fish DNA, proteins, and lipids. Rhamdia voulezi is a species of fish native to the Iguaçu river, Paraná, Brazil, that does not have scientific records of minimum (CTmin) and maximum (CTmax) temperatures required for survival. As it is a top predator species in the food chain and lives at temperatures below 22 °C, the loss of the species can cause functional problems in controlling the ecosystem and energy flow. The study evaluated the tissue metabolism of the brain, heart, and muscle of R. voulezi (n = 72) subjected to acute thermal stress of 31 °C for 2, 6, 12, 24, and 96 h after acclimatization to 21 °C. The biochemical markers SOD, GPx, MDH, HK, and CK of the brain, PCO of the heart and CAT, glycogen, G6PDH, and ALT of muscle were significant. PCA, IBR, thermal sensitive, and condition factor suggested that R. voulezi has different physiological strategies for acclimatization to 31 °C to mobilize and sustain the metabolic needs of oxygenation and energy allocation/utilization for tissue ATP production.

Sargassum spp. Ethanolic Extract Elicits Toxic Responses and Malformations in Zebrafish (Danio rerio) Embryos

The amount of Sargassum spp. arriving in the Caribbean Sea has increased steadily in the last few years, producing a profound environmental impact on the ecological dynamics of the coasts of the Yucatan Peninsula. We characterized the toxicological effects of an ethanolic extract of Sargassum spp. on zebrafish (Danio rerio) embryos (ZFEs) in a 96-h static bioassay using T1 (0.01 mg/L), T2 (0.1 mg/L), T3 (1 mg/L), T4 (10 mg/L), T5 (25 mg/L), T6 (50 mg/L), T7 (75 mg/L), T8 (100 mg/L), T9 (200 mg/L), and T10 (400 mg/L). In this extract, we detected 74 compounds by gas chromatography-mass spectrometry (GC-MS), of which hexadecanoic acid methyl ester, and 2-pentanone 4-hydroxy-4-methyl, were the most abundant. In ZFEs, a median lethal concentration of 251 mg/L was estimated. Exposed embryos exhibited extensive morphological changes, including edema in the yolk sac, scoliosis, and loss of pigmentation, as well as malformations of the head, tail, and eyes. By integrating these abnormalities using the Integrated Biological Response (IBRv2) and General Morphological Score (GMS) indices, we were able to determine that ZFEs exposed to 200 mg/L (T9) exhibited the most pronounced biological response in comparison with the other groups. In the comparative transcriptomic analysis, 66 genes were upregulated, and 246 genes were downregulated in the group exposed to 200 mg/L compared with the control group. In the upregulated genes, we identified several gene ontology-enriched terms, such as response to xenobiotic stimuli, cellular response to chemical stimulus, transcriptional regulation, pigment metabolic process, erythrocyte differentiation and embryonic hemopoiesis, extracellular matrix organization, and chondrocyte differentiation involved in endochondral bone morphogenesis, among others. In the down-regulated genes, we found many genes associated with nervous system processes, sensory and visual perception, response to abiotic stimulus, and the nucleoside phosphate biosynthetic process. The probable connections among the morphological changes observed in the transcriptome are thoroughly discussed. Our findings suggest that Sargassum spp. exposure can induce a wide negative impact on zebrafish embryos. Environ Toxicol Chem 2024;00:1-15. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Modified polymer membranes for the removal of pharmaceutical active compounds in wastewater and its mechanism-A review

Membrane technology can play a suitable role in removing pharmaceutical active compounds since it requires low energy and simple operation. Even though membrane technology has progressed for wastewater applications nowadays, modifying membranes to achieve the strong desired membrane performance is still needed. Thus, this study overviews a comprehensive insight into the application of modified polymer membranes to remove pharmaceutical active compounds from wastewater. Biotoxicity of pharmaceutical active compounds is first prescribed to gain deep insight into how membranes can remove pharmaceutical active compounds from wastewater. Then, the behavior of the diffusion mechanism can be concisely determined using mass transfer factor model that represented by β and B with value up to 2.004 g h mg-1 and 1.833 mg g-1 for organic compounds including pharmaceutical active compounds. The model refers to the adsorption of solute to attach onto acceptor sites of the membrane surface, external mass transport of solute materials from the bulk liquid to the membrane surface, and internal mass transfer to diffuse a solute toward acceptor sites of the membrane surface with evidenced up to 0.999. Different pharmaceutical compounds have different solubility and relates to the membrane hydrophilicity properties and mechanisms. Ultimately, challenges and future recommendations have been presented to view the future need to enhance membrane performance regarding fouling mitigation and recovering compounds. Afterwards, the discussion of this study is projected to play a critical role in advance of better-quality membrane technologies for removing pharmaceutical active compounds from wastewater in an eco-friendly strategy and without damaging the ecosystem.

Toxicological effects of diclofenac on signal crayfish (Pacifastacus leniusculus) as related to weakly acidic and basic water pH

The widespread use and continuous discharge of pharmaceuticals to environmental waters can lead to potential toxicity to aquatic biota. Pharmaceuticals and their metabolites are often complex organic and environmentally persistent compounds that are bioactive at low doses. This study aimed to investigate the effects of diclofenac (DCF) on the antioxidant defence system and neurotoxicity biomarkers in signal crayfish (Pacifastacus leniusculus) under weakly acidic and basic conditions. Crayfish were exposed to 200 µg/L of DCF at pH 6 and 8 for 96 h and subsequently underwent the depuration phase for 96 h. Gills, hepatopancreas, and muscle were sampled after the exposure and depuration phases to assess the toxicological biomarker responses of DCF in crayfish by evaluating lipid peroxidation (LPO) levels, activities of antioxidant enzymes and acetylcholinesterase. After the exposure phase, the hemolymph DCF concentration was detected one order higher at pH 6 than at pH 8. The DCF was subsequently fully eliminated from the hemolymph during the depuration phase. Our results showed that DCF caused alteration in the activities of six of the seven tested biomarkers in at least one crayfish tissue. Although exposure to DCF caused imbalances in the detoxification system on multiple tissue levels, it was regenerated to a balanced state after the depuration phase. Integrated biomarker response (IBRv2) showed that the highest toxicological response to DCF exposure was elicited in the gills, whereas the hepatopancreas was the highest-responding tissue after the depuration phase. Exposure to DCF at pH 6 caused higher toxicological effects than at pH 8; however, crayfish antioxidant mechanisms recovered more quickly at pH 6 than at pH 8 after the depuration phase. Our results showed that water pH influenced the toxicological effects of DCF, an ionisable compound in crayfish.

Evidence of genotoxicity, neurotoxicity, and antioxidant imbalance in silver catfish Rhamdia quelen after subchronic exposure to diisopentyl phthalate

Diisopentyl phthalate (DiPeP) is a plasticizer with significant offer and application in Brazilian industries. This is attributed to its origin, which is closely linked to the refining process of sugarcane for ethanol production in the country. In this work, we developed a model for trophic exposure to environmentally relevant doses (5, 25, and 125 ng/g of DiPeP) to identify possible target tissues and toxic effects promoted by subchronic exposure to DiPeP in a Neotropical catfish species (Rhamdia quelen). After thirty days of exposure, blood, liver, kidney, brain, and muscle were collected and studied regarding DNA damage in blood cells and biochemical analyses. The kidney was the most affected organ, as in the head kidney, genotoxicity was evidenced in all groups exposed to DiPeP. Besides, the caudal kidney showed a reduction in the superoxide dismutase and glutathione peroxidase activities as well as a reduced glutathione concentration. In the liver, exposure to 125 ng/g of DiPeP increased glutathione S-transferase activity and reduced glutathione levels. In muscle, acetylcholinesterase (AChE) was reduced. However, in the brain, an increase in AChE activity was observed after the exposure to lowest doses. In contrast, a significant reduction of brain AChE activity after exposure to the highest dose was detected. The pronounced genotoxicity observed in head kidney cells is of concern, as it may compromise different functions performed by this organ (e.g., hematopoiesis, immune and endocrine functions). In our study, DiPeP proved to be a compound of environmental concern since we have evidenced its nephrotoxic and neurotoxic potential even in low doses.

Single and combined effects of caffeine and salicylic acid on mussel Mytilus galloprovincialis: Changes at histomorphological, molecular and biochemical levels

Caffeine (CAF) and salicylic acid (SA) are frequently detected in waterbody, though information on their biological impact is poor. This work assesses the effects of CAF (5ng/L to 10µg/L) and SA (0.05µg/L to 100µg/L) alone and combined as CAF+SA (5ng/L+0.05µg/L to 10µg/L+100µg/L) on mussel Mytilus galloprovincialis under 12-days exposure by histomorphology of digestive gland and oxidative stress defense at molecular and biochemical levels. Besides evaluating tissue accumulation, absence of histomorphological damage and haemocyte infiltration highlighted activation of defensive mechanisms. Up-regulation of Cu/Zn-sod, Mn-sod, cat and gst combined with increased catalase and glutathione S-transferase activity were found in CAF-exposed mussels, while SA reduced ROS production and mitochondrial activity. CAF+SA exposure induced differential responses, and the integrated biomarker response (IBR) revealed more pronounced effects of SA than CAF. These results enlarge knowledge on pharmaceuticals impact on non-target organisms, emphasizing the need for proper environmental risk assessment.

Ocean acidification induces tissue-specific interactions with copper toxicity on antioxidant defences in viscera and gills of Asiatic hard clam Meretrix petechialis (Lamarck, 1818)

Toxicity of contaminants in organisms under ocean acidification (OA) has attracted increasing attention in ecotoxicological studies. This study investigated how pCO₂-driven OA affected waterborne copper (Cu) toxicity in antioxidant defences in viscera and gills of Asiatic hard clam Meretrix petechialis (Lamarck, 1818). Clams were continuously exposed to Cu at ambient relevant (0/no metal exposure, 10 and 50 μg L^-1) and polluted-high (100 μg L^-1) concentrations in unacidified (pH 8.10) and acidified (pH 7.70/moderate OA and 7.30/extreme OA) seawater for 21 days. Following coexposure, metal bioaccumulation and responses of antioxidant defence-related biomarkers to OA and Cu coexposure were investigated. Results showed that metal bioaccumulation was positively correlated with waterborne metal concentrations but was not notably influenced by OA conditions. Both Cu and OA affected the antioxidant responses to environmental stress. Additionally, OA induced tissue-specific interactions with Cu on antioxidant defences, varying with exposure conditions. In unacidified seawater, antioxidant biomarkers were activated to defend against oxidative stress induced by Cu and prevented clams from lipid peroxidation (LPO or MDA), but failed to defend against DNA damage (8-OHdG). OA exacerbated Cu toxicity in antioxidant defences and increased LPO levels in tissues. Gills and viscera adopted adaptive antioxidant defence strategies to manage oxidative stress, with the former being more vulnerable to oxidative stress than the latter. MDA and 8-OHdG were sensitive to OA and Cu exposure, respectively, and were useful bioindicators for assessing oxidative stress. Integrated biomarker response (IBR) and PCA can reflect the integrative responses of antioxidant biomarkers to environmental stress and illuminate the contributions of specific biomarkers to antioxidant defence strategies. The findings provided insights for understanding antioxidant defences against metal toxicity in marine bivalves under OA scenarios, which is essential into managing wild populations.

Paracetamol ecotoxicological bioassay using the bioindicators Lens culinaris Med. and Pisum sativum L

Paracetamol is one of the most widely used drugs worldwide, yet its environmental presence and hazardous impact on non-target organisms could rapidly increase. In this study, the possible cytotoxic effects of paracetamol were evaluated using two bioindicator plants Lens culinaris and Pisum sativum. Concentrations of 500, 400, 300, 200, 100, 50, 25, 5, 1 mg L-1, and a control (distilled water) were used for a total of 10 treatments, which were subsequently applied on seeds of Lens culinaris Med. and Pisum sativum L.; after 72 h of exposure, root growth, mitotic index, percentage of chromosomal abnormalities, and the presence of micronucleus were evaluated. The cytotoxic effect of paracetamol on L. culinaris and P. sativum was demonstrated, reporting the inhibition of root growth, the presence of abnormalities, and a significant micronucleus index at all concentrations used, which shows that this drug has a high degree of toxicity.

Multi-level responses of oysters Crassostrea virginica for assessing organochlorine pesticides in a Ramsar coastal lagoon in southern Mexico

Organochlorine pesticides (OCPs) have been intensively used without proper regulation and control in Latin America due to the prevalence of diseases and pests, thus posing potential risks to nontarget organisms. Initiatives for ecosystem preservation, such as to designate protected areas, may not be enough to avoid contamination by OCPs, considering that protected areas tend to be permeable to diffuse sources. Here, we investigate multi-level responses of the oyster Crassostrea virginica to OCPs in Laguna de Términos, a RAMSAR coastal lagoon in the southern Gulf of Mexico. For this aim, OCPs occurrence and concentrations in the water, sediment, and in oysters from 3 settlement banks were assessed. Enzymatic and non-enzymatic biochemical biomarkers were quantified in the oysters' mantle and digestive gland, and the human health risk due to oyster consumption was also evaluated. OCPs in water were below detection limits. Fourteen OCPs were detected in sediments (∑OCPs mean of 49 ngg^-1) and 7 in oyster tissues (∑OCPs mean of 121 ngg^-1). The occurrence of OCPs was related to the land uses along the watersheds of the rivers that drain into the lagoon. Biochemical responses were correlated with OCPs (∑HCH, ∑DDT, heptachlor and endosulfan) in sediment, and oyster tissues. OCPs in oyster tissues showed a strong association with pro-oxidant forces and oxidative stress responses (Superoxide dismutase, Catalase, Glutathione Peroxidase, and lipid peroxidation), and neurotoxicity (Acetylcholinesterase), suggesting that the current OCPs contamination exerts significant stress. Our study also shows that the consumption of oysters from the lagoon increases the potential human health risk. Considering that Laguna de Términos is a protected Ramsar site, we suggest that environmental protection measures should be increased and that a monitoring program for OCPs exposure is necessary to assess the effects on this ecosystem.

Evaluation of the toxicity of di-iso-pentyl-phthalate (DiPeP) using the fish Danio rerio as an experimental model

The presence of phthalates constitutes a risk to the health of aquatic environments and organisms. This work aimed to evaluate the toxic effects of di-iso-pentyl-phthalate (DiPeP) at environmentally relevant concentrations of 5, 25, and 125 µg/L in Danio rerio after subchronic exposure for 14 days. DiPeP altered the antioxidant system in the liver (125 μg/L), intestine (25 μg/L), brain, and gills in all concentrations tested. In animals exposed to 125 μg/L, DNA damage was identified in the gills. In addition, loss of cell boundary of hepatocytes, vascular congestion, necrosis in the liver, and presence of immune cells in the intestinal lumen were observed. Erythrocytic nuclear alterations in the blood occurred in animals exposed to 25 μg/L. DiPeP was quantified in muscle tissue at all exposure concentrations, appearing in a concentration-dependent manner. Contaminants such as DiPeP will still be used for a long time, mainly by industries, being a challenge for industry versus environmental health.

Can high- and low-temperature thermal stress modulate the antioxidant defense response of Astyanax lacustris brain?

Change in temperature of aquatic environment have impacts on the physiology of fish, especially in the brain, which is a vital organ and prone to oxidative damage. Astyanax lacustris is a freshwater fish that play an important role in the food market and has been increasingly used in fish farms, besides environmental monitoring studies. Therefore, this study aimed to evaluate the responses of antioxidant biomarkers and products of the oxidative process in the brains A. lacustris subjected to thermal shock. The specimens were obtained from artificial farming lakes and subjected to shock induced by exposure to high (31 °C ± 0.5) and low (15 °C ± 0.5) temperature for 2, 6, 12, 24, 48, 72 and 96 h; control group were maintained at 23 °C ± 0.5. At 31 °C, glutathione-related enzymes were more responsive, suggested by the change activity of GPx and G6PDH enzymes, in addition to GSH levels. At 15 °C, enzymes of the first line of defense were more active, evidenced by the change CAT activity. No significant changes were detected in the levels of ROS, LPO and PCO. These results indicate that the brains of A. lacustris have an efficient antioxidant defense system with the ability to acclimatize to the temperatures tested.

Integrated biomarker response to assess the effects of pesticide residues on Nile Tilapia in aquatic ecosystems contaminated by cotton-field effluents

An in-situ study combined with an integrated biomarker response was used to evaluate the impact of agricultural effluents in the physiological responses of Nile tilapia reared in cages and enclosures of water reservoirs in North Benin. Fish were distributed in fish farming systems at two sites: Songhai located outside the cotton basin and Batran located in the most productive commune. They were sampled for blood and organs before (BST), during (DST) and after (AST) pesticide treatment. Pesticide residues were analysed in water, sediments and fish muscles. Several biomarkers were investigated related to the immune (peroxidase, lysozyme and complement activities, superoxide anion production) and reproductive (sex steroids and vitellogenin levels) responses as well as neurotoxicity (cholinesterase activity) and tissue alterations. Biomarkers were assessed and analysed via the integrated biomarker response (IBR). The results showed that Batran water reservoir was a more harmful ecosystem for fish than Songhai one, especially by depressing some immune and reproductive functions in relation to a higher-level of pesticide contamination. They also demonstrated that the contact of fish to sediments in enclosures aggravated the pesticide burden on fish. Therefore, using males as bioindicators would improve the sensitivity of the used biomarkers since males seemed more affected than females especially due to pesticide estrogenic induction impacting their reproductive system.

Blood biochemical variables, antioxidative status, and histological features of intestinal, gill, and liver tissues of African catfish (Clarias gariepinus) exposed to high salinity and high-temperature stress

African catfish is a freshwater species with a high ability to resist brackish water conditions, but heat stress may impair the health status of fish. Thus, the impact of varying levels of water salinity (0, 4, 8, and 12 ppt) was investigated on the growth performance, survival rate, and blood biochemistry of African catfish (average weight: 180.58 ± 2.8 g and average length: 38 ± 1.2 cm) for 4 weeks; then, fish were stressed with high temperature (32 °C) for 72 h. The growth performance and survival rate were markedly higher in fish reared in 0, 4, and 8 ppt than fish in 12 ppt (p < 0.05). Before heat stress, the superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) activities, and malondialdehyde (MDA) levels were markedly increased in fish stressed with 12-ppt salinity (p < 0.05). After heat stress, all groups showed a marked increased SOD, CAT, GSH, and MDA levels than fish before heat stress in the same manner (p < 0.05). Furthermore, fish in the 12 ppt group showed severe intestinal, gill, and liver histological features. The levels of blood glucose and cortisol were markedly increased in fish exposed with 8 and 12 ppt than 0 ppt gradually either before or after heat stress (p < 0.05). The highest values of ALT, AST, urea, creatinine, and the lowest total protein, albumin, and globulin were observed in fish reared in 12 ppt. Significant salinity and heat stress interactions were seen on the ALT, AST, urea, creatinine, total protein, albumin, and globulin values (p < 0.05). The integrated multi-biomarker response (IBR) results showed marked differences among the groups and increased gradually before and after heat stress, with the highest IBR in 12 ppt. In conclusion, growing African catfish in high salinity (12 ppt) hampered the growth performance and health status while the heat stress improved the antioxidative status vis-a-vis increased lipid peroxidation along with higher stress-related markers in expressed both blood and tissue.

Low concentrations of ciprofloxacin alone and in combination with paracetamol induce oxidative stress, upregulation of apoptotic-related genes, histological alterations in the liver, and genotoxicity in Danio rerio

Nowadays, there are countless articles about the harmful effects of paracetamol (PCM) in non-target organisms. Nonetheless, information regarding the toxicity of ciprofloxacin (CPX) and the CPX-PCM mixture is still limited. Herein, we aimed to evaluate the hepatotoxic and genotoxic effects that ciprofloxacin alone and in combination with paracetamol may induce in Danio rerio adults. For this purpose, we exposed several D. rerio adults to three environmentally relevant concentrations of PCM (0.125, 0.250, and 0.500 μg/L), CPX (0.250, 0.500, and 1 μg/L), and their mixture (0.125 + 0.250, 0.250 + 0.500, and 0.500 + 1 μg/L) for 96 h. The blood samples showed CPX alone and in combination with PCM damaged the liver function of fish by increasing the serum levels of liver enzymes alanine aminotransferase and alkaline phosphatase. Moreover, our histopathological study demonstrated liver of fish suffered several tissue alterations, such as congestion, hyperemia, infiltration, sinusoidal dilatation, macrovascular fatty degeneration, and pyknotic nuclei after exposure to CPX alone and in combination with PCM. Concerning oxidative stress biomarkers and the expression of genes, we demonstrated that CPX and its mixture, with PCM, increased the levels of antioxidant enzymes and oxidative damage biomarkers and altered the expression of Nrf1, Nrf2, BAX, and CASP3, 6, 8, and 9 in the liver of fish. Last but not least, we demonstrated CPX alone and with PCM induced DNA damage via comet assay and increased the frequency of micronuclei in a concentration-dependent manner in fish. Overall, our results let us point out CPX, even at low concentrations, induces hepatotoxic effects in fish and that its combination with PCM has a negative synergic effect in the liver of this organism.

Remediation of pharmaceuticals from contaminated water by molecularly imprinted polymers: a review

The release of pharmaceuticals into the environment induces adverse effects on the metabolism of humans and other living species, calling for advanced remediation methods. Conventional removal methods are often non-selective and cause secondary contamination. These issues may be partly solved by the use of recently-developped adsorbents such as molecularly imprinted polymers. Here we review the synthesis and application of molecularly imprinted polymers for removing pharmaceuticals in water. Molecularly imprinted polymers are synthesized via several multiple-step polymerization methods. Molecularly imprinted polymers are potent adsorbents at the laboratory scale, yet their efficiency is limited by template leakage and polymer quality. Adsorption performance of multi-templated molecularly imprinted polymers depends on the design of wastewater treatment plants, pharmaceutical consumption patterns and the population serviced by these wastewater treatment plants.

Acute Exposure to Crude Oil Induces Epigenetic, Transcriptional and Metabolic Changes in Juvenile Sciaenops ocellatus

In this study, we report molecular and metabolic responses of Sciaenops ocellatus during an acute oil exposure bioassay (100, 800 and 8000 mg 1^-1 of crude oil). The global DNA methylation and expression profiles of key genes of the xenobiotic biotransformation system (cytochrome P450 1A [cyp1a] and glutathione S-tranferase [gst]), oxidative stress system (glutathione peroxidase [gpx], catalase [cat], aldehyde dehydrogenase [aldh]) and reproductive system (vitellogenin [vtg]) were evaluated. At the metabolic level, we evaluated the concentration of four polycyclic aromatic hydrocarbon (PAH) metabolites -hydroxybenzo[a]pyrene, hydroxypyrene, hydroxynaphthalene and hydroxyphenanthrene- in fish bile. The results of this study revealed that fish exposed to crude oil exhibited hypomethylation of DNA, up-regulation of cyp1a and gst and down-regulation of gpx, cat, aldh and vtg and high concentrations of PAH metabolites with respect to the control.

Toxicity assessment of earthworm exposed to arsenate using oxidative stress and burrowing behavior responses and an integrated biomarker index

Arsenate (As-V) is a ubiquitous contaminant in soil as a result of excessive use of veterinary drugs and pesticides, causing enormous environmental risks. Multiple biomarkers have been used to assess the ecotoxicity of arsenic, however, the mechanisms of toxicity remain unclear. This paper describes the exposure of the earthworm (Eisenia fetida) to natural soil with different As-V concentrations for 28 days, then biomarkers from oxidative stress and burrowing behavior were quantified to evaluate As-V stress. Dynamic changes in reactive oxygen species (ROS), lipid peroxidation (MDA), adenosine triphosphate (ATP) content and antioxidant enzymes activity (Gpx, SOD, CAT) implied two stages of intensified stress responses and physiological adaptability. The transcriptional expression and regulation of antioxidant enzymes showed different responses. The mRNA expression of sod1 was up-regulated, while that of cat showed no significant change. The related regulators, nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), showed dose-dependent activation, suggesting antioxidant defense induced by Nrf2 signaling. The burrowing behavior after 14-day exposure indicated that As-V inhibited burrowing activity, especially the burrow length and maximum burrow depth. These multiple biomarkers were integrated using a biomarker response index (BRI) model, which showed significant dose-effect relationship especially on day 28, and suggested that ATP was a sensitive and representative biomarker. This study provided evidence that burrowing activity, Nrf2 and HO-1 were useful biomarkers warranting inclusion into the BRI model. Arsenic toxicity was comprehensively understood through redox homeostasis regulation, biochemical and behavioral changes, and these results suggested new strategies for soil pollutants diagnosis.

Updating the use of biochemical biomarkers in fish for the evaluation of alterations produced by pharmaceutical products

The evaluation of toxic effects in stressful environmental conditions can be determined through the imbalance between exogenous factors (environmental contaminants) and enzymatic and non-enzymatic defenses in biological systems. The use of fish for the identification of alterations in biochemical biomarkers provides a comprehensive vision of the effects that pharmaceutical products cause in the aquatic ecosystem, as they are organisms with high sensitivity to contaminants, filtering capacity, and potential for environmental toxicology studies. A wide range of pharmaceuticals can stimulate or alter a variety of biochemical mechanisms, such as oxidative damage to membrane lipids, proteins, and changes in antioxidant enzymes. This review includes a summary of knowledge of the last 20 years, in the understanding of the different biochemical biomarkers generated by exposure to pharmaceuticals in fish, which include different categories of pharmaceutical products: NSAIDs, analgesics, antibiotics, anticonvulsants, antidepressants, hormones, lipid regulators and mixtures. This review serves as a tool in the design of studies for the evaluation of the effects of pharmaceutical products, taking into account the most useful biomarkers, type of matrix, enzyme alterations, all taking the pharmaceutical group of interest.

Effects of trophic 2,2', 4,4'-tetrabromodiphenyl ether (BDE-47) exposure in Oreochromis niloticus: A multiple biomarkers analysis

Polybrominated diphenyl esters are emerging environmental contaminants with few toxicological data, being a concern for the scientific community. This study evaluated the effects of BDE-47 on the health of Oreochromis niloticus fish. The animals were exposed to three doses of BDE-47 (0, 0.253, 2.53, 25.3 ng g^-1) every 10 days, for 80 days. The BDE-47 affected the hepatosomatic and gonadosomatic index in female and the condition factor by intermediate dose in both sexes. The levels of estradiol decreased and the T4 are increased, but the vitellogenin production was not modulated in male individuals. Changes in AChE, GST, LPO and histopathology were observed while the integrated biomarker response index suggests that the lowest dose of BDE-47 compromised the activity of antioxidant enzymes. The oral exposure to BDE-47 in environmental concentrations is toxic to O. niloticus and the use of multiple biomarkers is an attribution in ecotoxicology studies and biomonitoring programs.

Combined toxicity of micro/nano scale polystyrene plastics and ciprofloxacin to Corbicula fluminea in freshwater sediments

Plastic pollution has become a global environmental threat, and its potential to affect the bioavailability and toxicity of pharmaceuticals to aquatic organism are of growing concern. However, little is known regarding the combined toxicity of micro/nano-plastics and pharmaceuticals to benthic organisms in sediments. Thus, we employed a freshwater benthic bivalve, Corbicula fluminea (C. fluminea), to investigate the individual and co-toxicity of model plastics, microscopic fluorescent polystyrene (PS) (PS nano-plastic (PS-NP) and PS micro-plastic (PS-MP), 80 nm and 6 μm, respectively) and the common antibiotic ciprofloxacin (CIP) in formulated sediments. Our results suggest that oxidative damage and neurotoxicity were confirmed to occur in C. fluminea in all the treatments. The oxidative damage in the digestive glands reduced the clam ability to scavenge free radicals, causing severe tissue damage to the digestive glands of C. fluminea. Filtration rates of C. fluminea were significantly decreased in a concentration-dependent manner across all the treatments, which might be due to the inhibition of acetylcholinesterase activities. Interactions between CIP and micro/nano-plastic were observed, whereby the presence of PS decreased the toxicity of CIP in the digestive glands but aggravated the C. fluminea siphoning inhibition rate in the nano-plastic co-treatments group; in addition, the CIP toxicity to C. fluminea decreased because that the concentration of free dissolved CIP was lowered by micro/nano-PS. Taken together, the current study could contribute greatly to evaluating the ecological risk of CIP and PS in aquatic environments and sheds light on potential issues of food safety caused by both emerging pollutants.

Integrated multi-biomarker responses of juvenile rainbow trout (Oncorhynchus mykiss) to an environmentally relevant pharmaceutical mixture

Pharmaceuticals are emerging pollutants of concern for aquatic ecosystems where they are occurring in complex mixtures. In the present study, the chronic toxicity of an environmentally relevant pharmaceutical mixture on juvenile rainbow trout (Oncorhynchus mykiss) was investigated. Five pharmaceuticals (paracetamol, carbamazepine, diclofenac, naproxen and irbesartan) were selected based on their detection frequency and concentration levels in the Meuse river (Belgium). Fish were exposed for 42 days to three different concentrations of the mixture, the median one detected in the Meuse river, 10-times and 100-times this concentration. Effects on the nervous, immune, antioxidant, and detoxification systems were evaluated throughout the exposure period and their response standardized using the Integrated Biomarker Response (IBRv2) index. IBRv2 scores increased over time in the fish exposed to the highest concentration. After 42 days, fish exposed to the highest concentration displayed significantly higher levels in lysozyme activity (p < 0.01). The mixture also caused significant changes in brain serotonin turnover (p < 0.05). In short, our results indicate that the subchronic waterborne exposure to a pharmaceutical mixture commonly occurring in freshwater ecosystems may affect the neuroendocrine and immune systems of juvenile rainbow trout.

Minute Cu2+ coupling with HCO3- for efficient degradation of acetaminophen via H2O2 activation

Homogeneous Cu²⁺-mediated activation of H₂O₂ has been widely applied for the removal of organic contaminants, but fairly high dosage of Cu²⁺ is generally required and may cause secondary pollution. In the present study, minute Cu²⁺ (2.5 μM) catalyzed H₂O₂ exhibited excellent efficiency in degradation of organic pollutants with the assistant of naturally occurring level HCO₃^- (1 mM). In a typical case, acetaminophen (ACE) was completely eliminated within 10 min which followed the pseudo-first-order kinetics. Singlet oxygen and superoxide radical rather than traditionally identified hydroxyl radical were the predominant reactive oxygen species (ROS) responsible for ACE degradation. Meanwhile, Cu³⁺ was deduced through Cu⁺ and p-hydroxybenzoic acid formation analysis. CuCO₃(aq) was the main complex with high reactivity for the activation of H₂O₂ to form ROS and Cu³⁺. The removal efficiency of ACE depended on the operating parameters, such as Cu²⁺, HCO₃^- and H₂O₂ dosage, solution initial pH. The presence of Cl^-, HPO₄^2-, humic acid were found to retard ACE removal while other anions such as SO₄^2- and NO₃^- had no obvious effect. ACE exhibited lower degradation efficiency in real water matrices than that in ultra-pure water. Nevertheless, 58-100% of ACE was removed from domestic wastewater, lake water and tap water within 60 min. Moreover, eight intermediate products were identified and the possible degradation pathways of ACE were proposed. Additionally, other typical organic pollutants including bisphenol A, norfloxacin, lomefloxacin hydrochloride and sulfadiazine, exhibited great removal efficiency in the Cu²⁺/H₂O₂/HCO₃^- system.

Pharmaceuticals in a Mediterranean Basin: The influence of temporal and hydrological patterns in environmental risk assessment

Occurrence of pharmaceuticals in the aquatic environment is nowadays a well-established issue that has become a matter of both scientific and public concern. Tons of different classes of pharmaceuticals find their way to the environment at variable degrees, after their use and excretion through wastewater and sewage treatment systems. The main goal of this study was to correlate the dynamics and the environmental risk of pharmaceuticals with different temporal and hydrological patterns, at the Guadiana Basin (South of Portugal). Water samples were collected bimonthly during 2017 (classified as a drought year) and 2018 (post-drought year) in: Zebro, Álamos and Amieira (intermittent hydrological streams), and Lucefécit (perennial hydrological stream). The pharmaceuticals quantified in higher concentrations, out of 27 investigated, were diclofenac (up to 4806 ng L^-1), ibuprofen (3161 ng L^-1), hydrochlorothiazide (2726 ng L^-1) and carbamazepine (3223 ng L^-1). Zebro and Álamos presented the highest contamination by this group of environmental hazardous substances, which may be correlated with the presence of wastewater treatment plants upstream the sampling point of each stream. Furthermore, the highest concentrations occurred mainly during the dry period (2017), when the flow was nearly inexistent in Zebro, and in Álamos after the first heavy rainfalls. In specific periods, the high concentrations of pharmaceuticals detected may induce risk for the organisms of lowest trophic levels, damaging the balance of the ecosystems at these streams. The risk quotient optimised approach (RQf) integrating exposure, toxicity and persistence factors, ranks the pharmaceuticals investigated in terms of risk for the aquatic ecosystems as follows: diclofenac, ibuprofen and carbamazepine (high risk), clarithromycin (moderate risk), acetaminophen, ofloxacin and bezafibrate (endurable risk), and hydrochlorothiazide (negligible risk).