Chronic toxicity of diclofenac, carbamazepine and their mixture to Daphnia magna: a comparative two-generational study

Individual and combined toxicity of personal care products and pharmaceuticals at environmentally relevant concentrations due to chronic exposure of the freshwater microcrustacean Daphnia magna

Personal care products and pharmaceuticals, namely sodium diclofenac (DCF), octocrylene (OCT), and sodium dodecyl sulfate (SDS), are relevant chemical products classified as contaminants of emerging concern (CECs). They can enter aquatic ecosystems from various anthropogenic sources. This study examined the acute and chronic toxic effects of exposure to these substances, individually and in binary mixtures (OCT + SDS, SDS + DCF, DCF + SDS). Chronic effects were evaluated at environmentally relevant concentrations. To evaluate the mixtures, the Abbott method was used to predict acute toxicity using the inhibition ratio value, while for chronic effects, the concentration addition (CA) and independent action (IA) models were used for predictive assessment. According to EC5048h values, the toxicity levels to D. magna were OCT > SDS > DCF. When exposed to binary mixtures, these compounds predominantly exhibited antagonistic interaction for acute effects. Regarding chronic effects, there were no observed effects at the environmentally relevant concentrations tested for individual and mixed exposure compared to the control. The locomotion parameter exhibited a difference in dispersion with increasing chemical concentration. These results can improve understanding of the damage produced by exposure to mixtures of different CECs.

Environmental behavior, risks, and management of antidepressants in the aquatic environment

Antidepressants are increasingly detected in aquatic environments due to their incomplete removal in wastewater treatment, raising significant concerns about their ecological impacts. This review focuses on the three most widely used classes of antidepressants-tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs). It systematically explores their physicochemical properties and how these properties influence their environmental fate, including sorption, mobility, and bioaccumulation in aquatic ecosystems. The sublethal effects of these antidepressants on aquatic organisms, particularly their impacts on behavior, reproduction, and development, are critically analyzed, highlighting potential threats to biodiversity and ecological stability. Key knowledge gaps are identified, including the long-term impacts of chronic low-dose exposure, the role of bioactive metabolites, and the combined toxicity of antidepressants with other contaminants. The review underscores the importance of advanced wastewater treatment technologies, environmentally mindful prescribing practices, and public awareness campaigns as essential measures to mitigate these risks. By addressing these challenges, this study aims to inform future research and guide sustainable environmental management strategies.

Recent Advances in Nontargeted Screening of Chemical Hazards in Foodstuffs

The emergence of several chemical substances continues to enrich and facilitate the development of food science, but their irrational use also poses a threat to food safety and human health. Nontargeted screening (NTS) has become an important tool for rapid traceability and efficient identification of chemical hazards in food matrices. NTS in food analysis is highly integrated with sample pretreatment, instrumental analysis platforms, data acquisition and analysis, and toxicology. This article is a systemic review of current sample preparation, analytical platforms, and toxicity-guided NTS techniques and provides the latest advancements in workflows and innovative applications of the NTS process based on mass spectrometric techniques. High-throughput toxicity screening platforms play an important role in NTS of unknown chemical hazards of complex food matrices. Advanced machine learning and artificial intelligence are increasingly accessible fields that may effectively process large-scale screening data and advance food NTS research.

Ecological fitness impairments induced by chronic exposure to polyvinyl chloride nanospheres in Daphnia magna

The aim of this study was to evaluate the effects of chronic exposure (21 days) to an environmentally relevant concentration (10 μg/L) of two different nanoplastic (NP) polymers on the aquatic model organism Daphnia magna. This study examined the impact of exposure to 200 nm polystyrene nanoplastics (PS-NPs) and polyvinyl chloride nanoplastics (PVC-NPs), which had an average size similar to that of PS-NPs (ranging from 50 nm to 350 nm). The effects of polymer exposure on morphometric parameters, number of molts, swimming behaviour, and reproductive outcomes were evaluated. The findings indicate that PVC exposure induced higher body dimensions, while both polymers resulted in an increase in molting behaviour. Moreover, exposure to PVC-NPs had a negative impact on the reproduction of D. magna, as evidenced by a delay in the day of the first brood, a reduction in the total number of offspring produced, and, consequently, a slower population growth rate. It is hypothesised that the ingestion of PVC-NPs by D. magna may have resulted in an impairment of ecdysone hormone functionality and that the increased moulting events potentially representing an adaptive response to the negative effects of PVC-NP adhesion to the organism's body surfaces. These two organisms' responses could concur to explain the observed effects. This study identified the fitness impairments caused by exposure to PVC-NPs, which can lead to relevant ecological consequences. The comparative analysis of the effects induced by two types of polymers has revealed the generation of disparate hazards to D. magna. Furthermore, the chemical composition appears to be a pivotal factor in the onset of these effects. It can therefore be stated that PS is not a suitable standard for representing the toxicity of all plastics.

Transformation products of diclofenac: Formation, occurrence, and toxicity implication in the aquatic environment

Diclofenac (DCF) is the first drug on the EU Watch List of Priority Substances due to its extensive uses, incomplete removal in wastewater treatment plants (WWTPs), and toxic effects. Once in the environment, DCF undergoes processes that yield various transformation products (TPs) or metabolites, whichcan be more toxic than DCF. While these TPs or metabolites often dominate the majority of the drug load in municipal wastewater, they have been largely ignored. This review critically examines recent data on the formation, occurrence, fate, and toxicology of DCF TPs in the aquatic environment. This review reveals some important findings. First, DCF TPs may constitute >57 % of DCF in wastewater influent, ∼60 % in effluent, and ∼30 % in surface waters. Second, TPs persistently retain the core structure of DCF and may pose greater environmental risks than the parent drug. Third, some metabolites may revert back to the parent drug. Fourth, WWTPs serve as a consistent source that release DCF and its by-products into the environment. Fifth, mixtures of DCF and its metabolites, along with other contaminants, may pose elevated and synergistic environmental risks than individual compounds. These findings suggest that current risk assessment practices, which ignore the impacts of the metabolites and the chemical interactions/synergies, may seriously underestimate the overall toxicity of DCF and likely other pharmaceuticals. Further studies are needed to monitor the long-term fate and toxicity of the metabolites, as well as new analytical methods and standards to unveil the hidden metabolites and the associated environmental risks.

Toxicological assays in the evaluation of safety assessment of fibrinolytic enzymes

Cardiovascular diseases (CVDs) cause 30% of deaths each year, and in 2030, around 23.6 million people will die due to CVDs. The major challenge is to obtain molecules with minimal adverse reactions that can prevent and dissolve blood clots. In this context, fibrinolytic enzymes from diverse microorganism sources have been extensively investigated due to their potential to act directly and specifically on the fibrin clot, preventing side effects and performing potential thrombolytic effects. However, most researches focus on the purification and characterization of proteases, with little emphasis on the mechanism of action and pharmacological characteristics, including toxicity assays which are essential to assess safety and side effects. Therefore, this work aims to emphasize the importance of evaluations indicating the toxicological profile of fibrinolytic proteases through in vitro and in vivo tests. Both types of assays contribute as preclinical stage in drug development and are crucial for clinical applications. This scarcity creates arbitrary barriers to further studies. This work should further encourage the development of studies to ensure the safety and effectivity of fibrinolytic proteases.

Enzymatic degradability of diclofenac ozonation products: A mechanistic analysis

The treatment of waterborne micropollutants, such as diclofenac, presents a significant challenge to wastewater treatment plants due to their incomplete removal by conventional methods. Ozonation is an effective technique for the degradation of micropollutants. However, incomplete oxidation can lead to the formation of ecotoxic by-products that require a subsequent post-treatment step. In this study, we analyze the susceptibility of micropollutant ozonation products to enzymatic digestion with laccase from Trametes versicolor to evaluate the potential of enzymatic treatment as a post-ozonation step. The omnipresent micropollutant diclofenac is used as an example, and the enzymatic degradation kinetics of all 14 detected ozonation products are analyzed by high-performance liquid chromatography coupled with high-resolution mass spectrometry (HPLC-HRMS) and tandem mass spectrometry (MS2). The analysis shows that most of the ozonation products are responsive to chemo-enzymatic treatment but show considerable variation in enzymatic degradation kinetics and efficiencies. Mechanistic investigation of representative transformation products reveals that the hydroxylated aromatic nature of the ozonation products matches the substrate spectrum, facilitating their rapid recognition as substrates by laccase. However, after initiation by laccase, the subsequent chemical pathway of the enzymatically formed radicals determines the global degradability observed in the enzymatic process. Substrates capable of forming stable molecular oxidation products inhibit complete detoxification by oligomerization. This emphasizes that it is not the enzymatic uptake of the substrates but the channelling of the reaction of the substrate radicals towards the oligomerization of the substrate radicals that is the key step in the further development of an enzymatic treatment step for wastewater applications.

Bio-electrochemical degradation of carbamazepine (CBZ): A comprehensive study on effectiveness, degradation pathway, and toxicological assessment

Recent attention on the detrimental effects of pharmaceutically active compounds (PhACs) in natural water has spurred researchers to develop advanced wastewater treatment methods. Carbamazepine (CBZ), a widely recognized anticonvulsant, has often been a primary focus in numerous studies due to its prevalence and resistance to breaking down. This study aims to explore the effectiveness of a bio-electrochemical system in breaking down CBZ in polluted water and to assess the potential harmful effects of the treated wastewater. The results revealed bio-electro degradation process demonstrated a collaborative effect, achieving the highest CBZ degradation compared to electrodegradation and biodegradation techniques. Notably, a maximum CBZ degradation efficiency of 92.01% was attained using the bio-electrochemical system under specific conditions: Initial CBZ concentration of 60 mg/L, pH level at 7, 0.5% (v/v) inoculum dose, and an applied potential of 10 mV. The degradation pathway established by identifying intermediate products via High-Performance Liquid Chromatography-Mass Spectrometry, revealed the complete breakdown of CBZ without any toxic intermediates or end products. This finding was further validated through in vitro and in vivo toxicity assays, confirming the absence of harmful remnants after the degradation process.

Long-term dietary exposure to the non-steroidal anti-inflammatory drugs diclofenac and ibuprofen can affect the physiology of common carp (Cyprinus carpio) on multiple levels, even at "environmentally relevant" concentrations

The aim of the study was to evaluate the effects of emerging environmental contaminants, the non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac (DCF) and ibuprofen (IBP), on physiological functions in juvenile common carp (Cyprinus carpio). Fish were exposed for 6 weeks, and for the first time, NSAIDs were administered through diet. Either substance was tested at two concentrations, 20 or 2000 μg/kg, resulting in four different treatments (DCF 20, DCF 2000, IBP 20, IBP 2000). The effects on haematological and biochemical profiles, the biomarkers of oxidative stress, and endocrine disruption were studied, and changes in RNA transcription were also monitored to obtain a comprehensive picture of toxicity. Fish exposure to high concentrations of NSAIDs (DCF 2000, IBP 2000) elicited numerous statistically significant changes (p < 0.05) in the endpoints investigated, with DCF being almost always more efficient than IBP. Compared to control fish, a decrease in total leukocyte count attributed to relative lymphopenia was observed. Plasma concentrations of total proteins, ammonia, and thyroxine, and enzyme activities of alanine aminotransferase (ALT), aspartate aminotransferase, and alkaline phosphatase (ALP) were significantly elevated in either group, as were the activities of certain hepatic antioxidant enzymes (superoxide dismutase, glutathione-S-transferase) in the DCF 2000 group. The transcriptomic profile of selected genes in the tissues of exposed fish was affected as well. Significant changes in plasma total proteins, ammonia, ALT, and ALP, as well as in the transcription of genes related to thyroid function and the antioxidant defense of the organism, were found even in fish exposed to the lower DCF concentration (DCF 20). As it was chosen to match DCF concentrations commonly detected in aquatic invertebrates (i.e., the potential feed source of fish), it can be considered "environmentally relevant". Future research is necessary to shed more light on the dietary NSAID toxicity to fish.

Proteomic analysis of the hepatic response to a pollutant mixture in mice. The protective action of selenium

Metals and pharmaceuticals contaminate water and food worldwide, forming mixtures where they can interact to enhance their individual toxicity. Here we use a shotgun proteomic approach to evaluate the toxicity of a pollutant mixture (PM) of metals (As, Cd, Hg) and pharmaceuticals (diclofenac, flumequine) on mice liver proteostasis. These pollutants are abundant in the environment, accumulate in the food chain, and are toxic to humans primarily through oxidative damage. Thus, we also evaluated the putative antagonistic effect of low-dose dietary supplementation with the antioxidant trace element selenium. A total of 275 proteins were affected by PM treatment. Functional analyses revealed an increased abundance of proteins involved in the integrated stress response that promotes translation, the inflammatory response, carbohydrate and lipid metabolism, and the sustained expression of the antioxidative response mediated by NRF2. As a consequence, a reductive stress situation arises in the cell that inhibits the RICTOR pathway, thus activating the early stage of autophagy, impairing xenobiotic metabolism, and potentiating lipid biosynthesis and steatosis. PM exposure-induced hepato-proteostatic alterations were significantly reduced in Se supplemented mice, suggesting that the use of this trace element as a dietary supplement may at least partially ameliorate liver damage caused by exposure to environmental mixtures.

Can long-term salinity acclimation eliminate the inhibitory effect of salinization on anti-predation defense of Daphnia?

Freshwater salinization, due to road salt and other increased anthropogenic activities, has become a significant threat to freshwater organisms. However, whether freshwater salinization affects the response of aquatic organisms to their predators, especially prey that have been acclimated to salinity environments for a long time, remains unclear. In the present study, we investigated the changes in anti-predator defense of Daphnia magna with and without salinity acclimation at five different salinities (0, 0.6, 0.8, 0.10, and 0.12 M). Results showed that freshwater salinization weakened the induced defense response of D. magna, regardless of whether it had undergone long-term salinity acclimation. Specifically, induced defense traits such as smaller body size, higher relative spine length, more relative reproductive output, and smaller body size neonates disappeared at ≥ 0.08 M salinities. In addition, there were no significant differences in most traits of induced defense strength between D. magna with and without salinity acclimation at the same salinity. Importantly, the integrated induced defense response index decreased with increasing salinity. Our study showed that salinity-tolerant organisms do not recover their induced defense at high salinities, underlining the importance of incorporating interspecific interactions when estimating the effects of freshwater salinization on organisms.

Diclofenac eco-geno-toxicity in freshwater algae, rotifers and crustaceans

This study assessed the eco-genotoxic impact of diclofenac (DCF) in sentinel species of the freshwater ecosystem. DCF residues are found in freshwater from few ng/L to tens of μg/L due to the inability of conventional wastewater treatment plants to ensure removal efficiency of the drug. An ample body of literature reports on the acute toxicity of DCF in non-target organisms without addressing potential chronic long-term effects on organisms at actual, environmental concentrations. Herein, assessment for acute and chronic toxicity was performed on organisms in vivo exposed to DCF, specifically on the green alga Raphidocelis subcapitata, the rotifer Brachionus calyciflorus and the crustacean Ceriodaphnia dubia. Furthermore, potential DNA damage and expression of antioxidant genes (MnSOD, Cu/ZnSOD and CAT) were evaluated in crustacean neonates. The toxicological risk of DCF was assessed as well as its. GENOTOXIC RISK: The acute toxicity was observed at concentrations far from those of environmental concern. Rotifers and crustaceans were much more chronically sensitive than the algae to DCF, observing besides, the median effect concentrations at tens of μg/L. In crustaceans, DNA damage was noted at units of μg/L, revealing concentrations of environmental concern. The dysregulated activity of SOD and CAT also showed the ability of DCF to provoke oxidative stress. On assessment of environmental risk, the chronic Risk Quotient (RQ) was above the threshold value of 1. Nevertheless, the genotoxic RQ was significantly greater than the chronic RQ, thus, the need of regulatory bodies to acknowledge the genotoxic impact as an environmental risk factor. To our knowledge, this study is the first investigation to perform environmental genotoxic risk assessment of DCF.

Toxic effects of four emerging pollutants on cardiac performance and associated physiological parameters of the thick-shell mussel (Mytilus coruscus)

Robust cardiac performance is critical for the health and even survival of an animal; however, it is sensitive to environmental stressors. At present, little is known about the cardiotoxicity of emerging pollutants to bivalve mollusks. Thus, in this study, the cardiotoxic effects of four emergent pollutants, carbamazepine (CBZ), bisphenol A (BPA), tetrabromobisphenol A (TBBPA), and tris(2-chloroethyl) phosphate (TCEP), on the thick-shell mussel, Mytilus coruscus, were evaluated by heartbeat monitoring and histological examinations. In addition, the impacts of these pollutants on parameters that closely related to cardiac function including neurotransmitters, calcium homeostasis, energy supply, and oxidative status were assessed. Our results demonstrated that 28-day exposure of the thick-shell mussel to these pollutants resulted in evident heart tissue lesions (indicated by hemocyte infiltration and myocardial fibrosis) and disruptions of cardiac performance (characterized by bradyrhythmia and arrhythmia). In addition to obstructing neurotransmitters and calcium homeostasis, exposure to pollutants also led to constrained energy supply and induced oxidative stress in mussel hearts. These findings indicate that although do differ somehow in their effects, these four pollutants may exert cardiotoxic impacts on mussels, which could pose severe threats to this important species and therefore deserves more attention.