Chronic toxicity of the antiepileptic carbamazepine on the clam Ruditapes philippinarum

Multiple endpoints analysis of the effects of diesel oil on a commercial species, Carcinus maenas

Fuel spills in marine environments pose significant threats to aquatic ecosystems, evidencing the intricate relationship between fuel utilization and its impact on benthic species of commercial value for human consumption. This interconnectedness of human, animal and environmental welfare falls within the One Health framework. The aim of the present study was to evaluate the toxicological effects of diesel oil on the green crab Carcinus maenas, and make a parallelism between tested concentrations and petrogenic hydrocarbon levels in natural environments. Mortality, locomotion and feeding behavior, molting, somatic growth, morphological malformations, stress biomarkers, and nutritional variables were analyzed in three different bioassays. In Bioassay 1, prepuberal females were exposed to diesel oil water accommodated fraction (WAF) to determine the median lethal concentration (LC50) at different periods. In Bioassay 2, prepuberal females were exposed to 168 h LC50 and LC25 of diesel oil WAF for 7 days, and were subsequently exposed to clean water. In Bioassay 3, prepuberal females were exposed to 168 h LC12 and LC6 of diesel oil WAF for 30 days. Petrogenic hydrocarbon levels in the field were quantified at a port and a nature reserve, with concentrations of aromatic hydrocarbons being 1.92 μg/g in the former and below 0.01 μg/g in the latter. In Bioassay 1, the 168 h LC50 was estimated to be 1.04 % of diesel oil. The results obtained in Bioassays 2 (LC50 and LC25) and Bioassays 3 (LC12 and LC6) suggest that environmental exposure to petrogenic hydrocarbons produces high mortality or interferes with the molting process of crabs, leading to reduced growth and developmental abnormalities. Such malformations were observed in chelipeds, pereiopods, gills chambers and eye peduncles, and affected feeding and locomotion behaviors. Overall, this could impact on population size and health, and consequently alter the ecological role and commercial exploitation of economically important species like C. maenas.

Mytilus galloprovincialis: A valuable bioindicator species for understanding the effects of diclofenac under warming conditions

Drugs are chemical compounds used to treat and improve organic dysfunctions caused by diseases. These include analgesics, antibiotics, antidepressants, and antineoplastics. They can enter aquatic environments through wastewater streams, where their physico-chemical properties allow metabolites to distribute and accumulate. Current climate change and associated extreme weather events may significantly impact these substances' toxicity and aquatic organisms' sensitivity. Among the chemicals present in aquatic environments is the non-steroidal anti-inflammatory drug diclofenac (DIC), which the EU monitors due to its concentration levels. This study investigated the influence of temperature (control at 17 °C vs. 21 °C) on the effects of DIC (0 μg/L vs. 1 μg/L) in the mussel species Mytilus galloprovincialis. Significant results were observed between 17 and 21 °C. Organisms exposed to the higher temperature showed a decrease in several parameters, including metabolic capacity and detoxification, particularly with prolonged exposure. However, in some parameters, after 21 days, the M. galloprovincialis showed no differences from the control, indicating adaptation to the stress. The results of this study confirm that DIC concentrations in the environment, particularly when combined with increased temperatures, can produce oxidative stress and adversely affect M. galloprovincialis biochemical and physiological performance. This study also validates this species as a bioindicator for assessing environmental contamination with DIC. Beyond its direct impact on aquatic organisms, the presence of pharmaceuticals like DIC in the environment highlights the interconnectedness of human, animal, and ecosystem health, underscoring the One Health approach to understanding and mitigating environmental pollution.

Unravelling biochemical responses in the species Mytilus galloprovincialis exposed to the antineoplastics ifosfamide and cisplatin under different temperature scenarios

This study investigates the chronic impact of two of the most widely consumed antineoplastic drugs, Ifosfamide (IF) and Cisplatin (CDDP), on the bivalve species Mytilus galloprovincialis under current (17 °C) and predicted warming conditions (21 °C). Accompanying the expected increase in worldwide cancer incidence, antineoplastics detection in the aquatic environment is also expected to rise. Mussels were exposed to varying concentrations of IF (10, 100, 500 ng/L) and CDDP (10, 100, 1000 ng/L) for 28 days. Biochemical analyses focused on metabolic, antioxidant and biotransformation capacities, cellular damage, and neurotoxicity. Results showed temperature-dependent variations in biochemical responses. Metabolic capacity remained stable in mussels exposed to IF, while CDDP exposure increased it at 1000 ng/L for both temperatures. Antioxidant enzyme activities were unaffected by IF, but CDDP activated them, particularly at 21 °C. Biotransformation capacity was unchanged by IF but enhanced by CDDP. Nevertheless, cellular damage occurred at CDDP concentrations above 100 ng/L, regardless of temperature. Integrated biomarker responses highlighted CDDP's greater impact, emphasizing the critical role of temperature in shaping organismal responses and underscoring the complexity of environmental stressor interactions.

Praseodymium and warming interactions in mussels: Comparison between observed and predicted results

Being a crucial element for technological development, praseodymium (Pr) has been increasingly used, leading to a rise in its concentration in aquatic systems. However, its potential threats to organisms remain poorly understood. Besides contamination, organisms are also threatened by climate change-related factors, including warming. It is important to evaluate how climate change-related factors may influence the effects of contaminants. To address this, histopathological and biochemical analyses were performed in adult mussels of Mytilus galloprovincialis, following a 28-day exposure to Pr (10 μg/L) and warming (4 °C increase) separately, and in combination. Additionally, biochemical and physiological alterations were analysed in the sperm of mussels after 30-min exposure to the same treatments. Furthermore, it was used the Independent Action model to predict the interaction between Pr and warming. The results showed, in the case of adults exposed to Pr, an increase in superoxide dismutase (SOD) and glutathione S-transferases (GSTs) activities. However, it was insufficient, leading to histopathological injuries, redox imbalance, and cellular damage. In the case of sperm, Pr induced an increase of mitochondrial activity and respiration rate, in response to the increase in systemic metabolic rate and oxygen demand. Warming increased the metabolism, and induced redox imbalance and cellular damage in adults. In sperm, a rise in temperature induced lipid peroxidation and a decrease in velocity. Warming induced some alterations in how adult mussels responded to Pr, activating catalase instead of SOD, and in addition to GSTs, also activated carboxylesterases. However, it was not enough to avoid redox imbalance and cellular damage. In the case of sperm, the combination induced a decrease in H2O2 production, and higher oxygen demand, which prevented the decrease in motility and velocity. This study highlights the limitations of using models and emphasizes the importance of studying the impacts of emerging contaminants, such as rare earth elements, and their combination with climate change-related factors. Under environmental conditions, chronic exposure to the combined effect of different stressors might generate impacts at higher biological levels. This may affect organisms' respiratory and filtration capacity, nutrient absorption, defence capacity against infections or diseases, and sperm viability, ultimately resulting in reduced growth and reproduction, with consequences at the population level.

The role of warming in modulating neodymium effects on adults and sperm of Mytilus galloprovincialis

The use of rare earth elements (REEs) has been increasing and one of the most used is neodymium (Nd). Being an emergent contaminant, its negative impacts are poorly understood. Aquatic organisms are also threatened by climate change-related factors, as is the case of warming, which can change the effects of REEs. Thus, the impacts of Nd, warming, and the combination of both stressors were studied in adult mussels and sperm of the species Mytilus galloprovincialis, after an exposure period of 28 days (adults) and 30 min (sperm). The effects were evaluated through the analysis of biochemical and histopathological alterations in adults and biochemical and physiological responses given by sperm. The results showed that mussels only activated their biotransformation capacity when exposed to the stressors acting alone, which was insufficient to avoid lipid peroxidation. Furthermore, warming (alone and combined with Nd) also produces damage to proteins. The digestive gland was the most sensitive organ to Nd, presenting several histopathological alterations. In the case of sperm, all stressors induced lipid peroxidation, a higher oxygen demand, and a decrease in velocity, even if the sperm viability was maintained. It seems that warming influenced the effects of Nd to some extent. The present findings contribute significantly to the field of REEs environmental toxicology by offering valuable insights into the impacts of Nd on various biological levels of mussels. Additionally, within the context of climate change, this study sheds light on how temperature influences the effects of Nd. The obtained results indicate that both stressors can potentially compromise the overall health of mussel populations, thereby affecting other species reliant on them for food and habitat. Moreover, this study highlights impaired sperm health, which could adversely affect their reproductive capacity and ultimately lead to population decline.

Yttrium effects on the Mediterranean mussel under a scenario of salinity shifts and increased temperature

Climate change (CC) induces significant worldwide alterations in salinity and temperature, impacting ecosystems and their services. Marine organisms, susceptible to these changes, may experience modified vulnerability to anthropogenic contaminants, including rare-earth elements (REEs) such as yttrium (Y) derived from electronic waste. This study investigated the influence of temperature and salinity changes on the impacts of Y in Mytilus galloprovincialis mussels. Organisms were subjected to Y (0 and 10 μg/L) for 28 days under three salinity scenarios (20, 30 (control), and 40, at a control temperature of 17 °C) or to two temperatures (17 and 22 °C, at the control salinity of 30). Under these conditions, Y bioaccumulation and different biomarkers were evaluated. Results showed that salinity and temperature did not affect Y accumulation, indicating effective detoxification mechanisms and physiological adaptations in the exposed organisms. However, in Y-exposed mussels effects were intensified under decreased salinity, evidenced by increased metabolism, defense enzyme activities, and acetylcholinesterase (AChE) levels. Similar responses occurred under heat stress with enhanced metabolic capacity, AChE activity, and activation of defense mechanisms such as glutathione S-transferases. These defense mechanisms mitigated cellular damage caused by Y, but under the highest temperature and especially lower salinity, Y-exposed mussels exhibited increased oxidative stress and decreased efficiency of activated defense enzymes, resulting in cellular damage compared to their uncontaminated counterpart. The present study sheds light on the effects that interactions between temperature, salinity, and the presence of emerging contaminants like REEs may have on marine organisms. Such assessments are crucial for developing effective strategies to mitigate the impacts of CC and protect the long-term health and resilience of marine ecosystems.

Can temperature rise change the impacts induced by e-waste on adults and sperm of Mytilus galloprovincialis?

Nowadays, it is of utmost importance to consider climate change factors, such as ocean warming, since the risk of negative impacts derived from increased surface water temperature is predicted to be high to the biodiversity. The need for renewable energy technologies, to reduce greenhouse gas emissions, has led to the increasing use of rare earth elements (REEs). Dysprosium (Dy) is widely used in magnets, motors, electrical vehicles, and nuclear reactors, being considered a critical REE to technology due to its economic importance and high supply risk. However, the increasing use of this element contributes to the enrichment of anthropogenic REEs in aquatic systems. Nevertheless, the information on the potential toxicity of Dy is limited. Moreover, the effects of pollutants can be amplified when combined with climate change factors. Thus, this study aimed to assess the effects of Dy (10 μg/L) in the species Mytilus galloprovincialis under actual (17 °C) and predicted warming conditions (21 °C). The Dy concentration in contaminated mussels was similar between temperatures, probably due to the detoxification capacity in individuals under these treatments. The combined stressors affected the redox balance, but higher impacts were caused by Dy and warming acting alone. In terms of cellular damage, although Dy acting alone was prejudicial to mussels, warming and both stressors acting together induced higher levels of LPO and PC. The histopathological effects of Dy in the digestive tubules were independent of the temperature tested. Regarding effects on sperm, only warming induced cellular damage, while both stressors, alone and together, impaired sperm movement. Overall, this study highlights that warming might influence the effects induced by Dy, but greater impacts were caused by the element. Eventually, the tested stressors may have consequences on mussels' reproduction capacity as well as their growth, abundance, and survival.

Bioaccumulation and molecular effects of carbamazepine and methylmercury co-exposure in males of Dreissena polymorpha

Dreissena polymorpha is a bivalve promising for biomonitoring in freshwater ecosystems thanks to its abundance and high filtration activity allowing rapid uptake of toxicants and identification of their negative effects. Nonetheless, we still lack knowledge on its molecular responses to stress under realistic scenario, e.g. multi-contamination. Carbamazepine (CBZ) and Hg are ubiquitous pollutants sharing molecular toxicity pathways, e.g. oxidative stress. A previous study in zebra mussels showed their co-exposure to cause more alterations than single exposures, but molecular toxicity pathways remained unidentified. D. polymorpha was exposed 24 h (T24) and 72 h (T72) to CBZ (6.1 ± 0.1 μg L-1), MeHg (430 ± 10 ng L-1) and the co-exposure (6.1 ± 0.1 μg L-1CBZ and 500 ± 10 ng L-1 MeHg) at concentrations representative of polluted areas (~10× EQS). RedOx system at the gene and enzyme level, the proteome and the metabolome were compared. The co-exposure resulted in 108 differential abundant proteins (DAPs), as well as 9 and 10 modulated metabolites at T24 and T72, respectively. The co-exposure specifically modulated DAPs and metabolites involved in neurotransmission, e.g. dopaminergic synapse and GABA. CBZ specifically modulated 46 DAPs involved in calcium signaling pathways and 7 amino acids at T24. MeHg specifically modulated 55 DAPs involved in the cytoskeleton remodeling and hypoxia-induced factor 1 pathway, without altering the metabolome. Single and co-exposures commonly modulated proteins and metabolites involved in energy and amino acid metabolisms, response to stress and development. Concomitantly, lipid peroxidation and antioxidant activities were unchanged, supporting that D. polymorpha tolerated experimental conditions. The co-exposure was confirmed to cause more alterations than single exposures. This was attributed to the combined toxicity of CBZ and MeHg. Altogether, this study underlined the necessity to better characterize molecular toxicity pathways of multi-contamination that are not predictable on responses to single exposures, to better anticipate adverse effects in biota and improve risk assessment.

Chronic exposure to bisphenol A induces behavioural, neurochemical, histological, and ultrastructural alterations in the ganglia tissue of the date mussels Lithophaga lithophaga

Bisphenol A (BPA), a common plastic additive, has been demonstrated mechanistically to be a potential endocrine disruptor and to affect a variety of body functions in organisms. Although previous research has shown that BPA is toxic to aquatic organisms, the mechanism of neurotoxic effects in marine bivalves remains unknown. The current study aimed to elucidate the neurotoxic effects of BPA when administered at different concentrations (0.25, 1, 2, and 5 µg/L) for twenty-eight days in the ganglia of a bivalve model, the Mediterranean mussel (Lithophaga lithophaga), which is an ecologically and economically important human food source of bivalve species in the Mediterranean Sea. Our findings revealed an increase in behavioural disturbances and malondialdehyde levels in treated mussel ganglia compared to the control group. Furthermore, superoxide dismutase activity increased in the ganglia of L. lithophaga treated with 0.25 and 2 µg/L. However, at BPA concentrations of 1 and 5 µg/L, SOD activity was significantly reduced, as was total glutathione concentration. BPA causes neurotoxicity, as evidenced by concentration-dependent inhibition of acetylcholinesterase, dopamine, and serotonin. After chronic exposure to BPA, neurons showed distortion of the neuronal cell body and varying degrees of pyknosis. The ultrastructure changes in BPA-treated groups revealed the lightening of the nucleoplasm and a shrunken nuclear envelope. Overall, our findings suggest that BPA exposure altered antioxidation, neurochemical biomarkers, histopathological, and ultrastructural properties, resulting in behavioural changes. As a result, our findings provide a basis for further study into the toxicity of BPA in marine bivalves.

Individual and combined effects of amoxicillin and carbamazepine to the marine copepod Tigriopus fulvus

Pharmaceuticals can be considered a global threat to aquatic ecosystems due to their pseudo-persistence and their potential toxicity towards non-target species. Amoxicillin (AMX) and carbamazepine (CBZ) and their mixture (1:1) were investigated on the marine copepod Tigriopus fulvus (Fischer, 1860) considering both acute and chronic endpoints. While acute and chronic exposure did not directly affect survival, reproductive endpoints were affected like the mean egg hatching time that was significantly longer than the negative control for treatments with AMX (0.789 ± 0.079 μg/L), CBZ (8.88 ± 0.89 μg/L), and AMX and CMZ as a mixture (1.03 ± 0.10 μg/L and 0.941 ± 0.094 μg/L), in that order.

Design of Fmoc-Phenylalanine Nanofibrillar Hydrogel and Mechanistic Studies of Its Antimicrobial Action against Both Gram-Positive and Gram-Negative Bacteria

In pursuit of efficient antimicrobial agents, biomaterials such as hydrogels have drawn a considerable amount of attention due to their numerous advantages such as a high degree of hydration, biocompatibility, stability, and direct application at an infectious site. Particularly, biomaterials such as hydrogels based on Fmoc-protected peptides and amino acids have proven to be immensely advantageous. Such biomaterials can undergo gelation by simple pH modulation and can be used for various biological applications. Keeping this in mind, in this work, we reported the synthesis of Fmoc-phenylalanine (Fmoc-F)-based hydrogels using trisodium citrate as a pH modulator and compared them with the previously reported pH modulator glucono-δ-lactone. The gels were compared using various characterization techniques such as rheometry, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), small angle X-ray scattering (SAXS), FT-IR, thioflavin T (ThT) binding assay, and zeta potential studies. These studies highlighted the role of pH modulators in affecting various parameters such as the ability to alter the zeta potential of the nanofibrils, improve their bactericidal action, reduce the amyloidic characters, shift the lattice packing from amorphous to crystalline, and introduce fluorescence and thermoreversibility. Interestingly, this is the first report where the Fmoc-F-based hydrogel has been shown to be effective against Gram-negative bacteria along with Gram-positive bacteria as well. Additionally, the mechanism of antimicrobial action was investigated using docking and antioxidant studies.

Threats of Pollutants Derived from Electronic Waste to Marine Bivalves: The Case of the Rare-Earth Element Yttrium

The production of electrical and electronic equipment waste (e-waste) is increasing at an alarming rate worldwide. This may eventually lead to its accumulation in aquatic environments, mainly because of the presence of nonbiodegradable components. The rare-earth element yttrium (Y) is particularly relevant because it is present in a wide variety of electro-based equipment. Within this context, the present study investigated the biological consequences of anthropogenic Y exposure in Mytilus galloprovincialis. Mussels were exposed to Y (0, 5, 10, 20, 40 μg/L) for 28 days, and their bioaccumulation and biomarkers related to metabolism, oxidative stress defenses, cellular damage, and neurotoxicity were evaluated. The results revealed that tissue Y content increased at increasing exposure concentrations (though the bioconcentration factor decreased). At the lowest Y dosage (5 µg/L), mussels lowered their electron transport system (ETS) activity, consumed more energy reserves (glycogen), and activated superoxide dismutase activity, thus preventing cellular damage. At the highest Y dosage (40 μg/L), mussels reduced their biotransformation activities with no signs of cellular damage, which may be associated with the low toxicity of Y and the lower/maintenance of ETS activity. Although only minor effects were observed, the present findings raise an environmental concern for aquatic systems where anthropogenic Y concentrations are generally low but still may compromise organisms' biochemical performance. Particularly relevant are the alterations in energy metabolism and detoxification processes for their longer-term impacts on growth and reproduction but also as defense mechanisms against other stressors. Environ Toxicol Chem 2023;42:166-177. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Ecotoxicological effects of the UV-filter 4-MBC on sperms and adults of the mussel Mytilus galloprovincialis

Present in an increasing number of products, UV-filters are continuously discharged into aquatic environments. Despite potential risks for inhabiting organisms are recognized, the effects of UV-filter 4-methylbenzylidenecamphor (4-MBC) on marine invertebrates are poorly investigated. By combining in vitro/in vivo exposures through a multi-biomarker approach on sperms and adults, the present study evaluated how 4-MBC affect the mussel species Mytilus galloprovincialis, providing ecologically relevant information on organisms' responses. From the obtained results, considering mortality as endpoint, sperms revealed a greater sensitivity (EC₅₀:347 μg/L) than adults (EC₅₀: not calculable). From an ecotoxicological perspective, this resulted in a derived threshold concentration (LOEC) of 100 μg/L and 72 μg/L, respectively. Effects at the cell/molecular level were provided by general redox-status imbalance and oxidative stress. Sperms showed functional and structural impairments, hyperactivation and DNA damage, while adults showed physiological, metabolic/energetic dysfunctions, DNA damage and activation of oxidative and biotransformation enzymes. High 4-MBC bioaccumulation was also observed in exposed mussels (BCFs:14.0-32.0 L/kg). These findings suggest that 4-MBC may impair fitness and survival of the broadcast spawning mussel M. galloprovincialis, affecting reproduction success and population growth.

Antioxidant capacity and carbon-based scope for growth of brackish water clams Corbicula japonica under the combined effects of natural and anthropogenic factors

Changes in natural estuarine environment and anthropogenic disturbances are becoming significant threats to organisms, particularly bivalves. A deeper understanding of the relationship between biochemical- and individual-level responses is necessary to assess the combined effects of natural and anthropogenic factors on bivalves. To the best of our knowledge, this is the first study where the oxygen radical absorbance capacity (ORAC) and carbon-based scope for growth (C-SFG) were applied as biomarkers to evaluate the response of the brackish water clam Corbicula japonica to four spatiotemporally varying environmental factors. High water temperature and food availability supported C-SFG while high salinity inhibited it. Most of wastewater (WW) treatments resulted in negative C-SFG values because of a reduced clearance rate and increased excretion rate. In particular, high food availability with WW treatment resulted in the lowest C-SFG value of -114 μg C·ind^-1 h^-1. The ORAC was activated in response to high salinity with WW treatment (p < 0.05). To ascertain the combined effects of the natural and anthropogenic factors, principal component and cluster analyses were performed on the ORAC and C-SFG data. Anthropogenic WW was found to have different effects on the physiological and biochemical biomarkers according to the natural conditions. A roughly negative correlation was observed between ORAC and C-SFG because activation of the antioxidant capacity can influence the growth potential of the clams through the additional use of available metabolic energy. However, some exceptions were observed where both the ORAC and C-SFG values were either high or low, which could be because the C-SFG response varies depending on different metabolic behaviors even when the ORAC response remains the same. These results indicate that the biochemical-level response (i.e., ORAC) of C. japonica can be interpreted using individual-level response (i.e., C-SFG), but careful attention must be given to over- or underestimation.

Multi-biomarker approach to evaluate the neurotoxic effects of environmentally relevant concentrations of phenytoin on adult zebrafish Danio rerio

Several studies have reported the presence of phenytoin (PHE) in wastewater treatment plant effluents, hospital effluents, surface water, and even drinking water. However, published studies on the toxic effects of PHE at environmentally relevant concentrations in aquatic organisms are scarce. The present study aimed to determine the effect of three environmentally relevant concentrations of PHE (25, 282, and 1500 ng L^-1) on behavioral parameters using the novel tank test. Moreover, we also aimed to determine whether or not these concentrations of PHE may impair acetylcholinesterase (AChE) activity and oxidative status in the brain of Danio rerio adults. Behavioral responses suggested an anxiolytic effect in PHE-exposed organisms, mainly observed in organisms exposed to 1500 ng L^-1, with a significant decrease in fish mobility and a significant increase in activity at the top of the tank. Besides the behavioral impairment, PHE-exposed fish also showed a significant increase in the levels of lipid peroxidation, hydroperoxides, and protein carbonyl content compared to the control group. Moreover, a significant increase in brain AChE levels was observed in fish exposed to 282 and 1500 ng L^-1. The results obtained in the present study show that PHE triggers a harmful response in the brain of fish, which in turn generates fish have an anxiety-like behavior.

Metabolic, cellular and defense responses to single and co-exposure to carbamazepine and methylmercury in Dreissena polymorpha

Carbamazepine (CBZ) and Hg are widespread and persistent micropollutants in aquatic environments. Both pollutants are known to trigger similar toxicity mechanisms, e.g. reactive oxygen species (ROS) production. Here, their effects were assessed in the zebra mussel Dreissena polymorpha, frequently used as a freshwater model in ecotoxicology and biomonitoring. Single and co-exposures to CBZ (3.9 μg L^-1) and MeHg (280 ng L^-1) were performed for 1 and 7 days. Metabolomics analyses evidenced that the co-exposure was the most disturbing after 7 days, reducing the amount of 25 metabolites involved in protein synthesis, energy metabolism, antioxidant response and osmoregulation, and significantly altering cells and organelles' structure supporting a reduction of functions of gills and digestive glands. CBZ alone after 7 days decreased the amount of α-aminobutyric acid and had a moderate effect on the structure of mitochondria in digestive glands. MeHg alone had no effect on mussels' metabolome, but caused a significant alteration of cells and organelles' structure in gills and digestive glands. Single exposures and the co-exposure increased antioxidant responses vs control in gills and digestive glands, without resulting in lipid peroxidation, suggesting an increased ROS production caused by both pollutants. Data globally supported that a higher number of hyperactive cells compensated cellular alterations in the digestive gland of mussels exposed to CBZ or MeHg alone, while CBZ + MeHg co-exposure overwhelmed this compensation after 7 days. Those effects were unpredictable based on cellular responses to CBZ and MeHg alone, highlighting the need to consider molecular toxicity pathways for a better anticipation of effects of pollutants in biota in complex environmental conditions.

Metabolic and oxidative status alterations induced in Ruditapes philippinarum exposed chronically to estrogen 17α-ethinylestradiol under a warming scenario

The presence of pharmaceuticals in the aquatic environment is an ongoing concern. However, the information regarding their effects under different climate change scenarios is still scarce. 17α-ethinylestradiol (EE2) is widely present in different aquatic systems showing negative impacts on aquatic organisms even when present at trace concentrations (≈1 ng/L). Nevertheless, its impact on bivalves is poorly understood, especially considering the influence of climate change factors. This study aimed to assess the toxicological impacts of EE2 under current and predicted warming scenarios, in the edible clam Ruditapes philippinarum. For this, clams were exposed for 28 days to different EE2 concentrations (5, 25, 125, 625 ng/L), under two temperatures (17 °C (control) and 21 °C). Drug concentrations, bioconcentration factors and biochemical parameters, related to oxidative stress and energy metabolism, were evaluated. Results showed that under actual and predicted temperature scenarios EE2 concentrations led to a disturbance in redox homeostasis of the clams, characterized by an increase in oxidized glutathione in contaminated organisms compared to control ones. Nevertheless, clams were capable to cope with the stressful conditions, activating their defence mechanisms (especially at the highest exposure concentration and in particular at increased temperature), and no oxidative damage occured. Although limited effects were observed, the present findings indicate that under both temperatures contaminated clams altered their biochemical performance, which can impair their sensitivity and protection capacity to respond to other environmental changes and/or affect their capacity to grow and reproduce. The results presented here highlight the need for further research on this thematic, considering that climate change is an ongoing problem, and the levels of some pharmaceutical drugs will continue to increase in marine/estuarine environments.

Salinity-dependent impacts on the effects of antiepileptic and antihistaminic drugs in Ruditapes philippinarum

In coastal systems, pollutants as pharmaceutical drugs exert changes from the molecular to the organism level in marine bivalves. Besides pollutants, coastal systems are prone to changes in environmental parameters, as the alteration of salinity values because of Climate Change. Together, these stressors (pharmaceutical drugs and salinity changes) can exert different threats than each stressor acting individually; for example, salinity can change the physical-chemical properties of the drugs and/or the sensitivity of the organisms to them. However, limited information is available on this subject, with variable results, and for this reason, this study aimed to evaluate the impacts of salinity changes (15, 25 and 35) on the effects of the antiepileptic carbamazepine (CBZ, 1 μg/L) and the antihistamine cetirizine (CTZ, 0.6 μg/L), when acting individually and combined (CBZ + CTZ), in the edible clam Ruditapes philippinarum. After 28 days of exposure, drugs concentrations, bioconcentration factors and biochemical parameters, related to clam's metabolic capacity and oxidative stress were evaluated. The results showed that clams under low salinity suffered more changes in metabolic, antioxidant and biotransformation activities, in comparison with the remaining salinities under study. However, limited impacts were observed when comparing drug effects at low salinity. Indeed, it seemed that CTZ and CBZ + CTZ, under high salinity (salinity 35) were the worst exposure conditions for the clams, since they caused higher levels of cellular damage. It stands out that salinity changes altered the impact of pharmaceutical drugs on marine bivalves.

Differential tissue accumulation in the invasive Manila clam, Ruditapes philippinarum, under two environmentally relevant lanthanum concentrations

Among the environmental emerging concern rare earth elements, lanthanum (La) is one of the most common and reactive. Lanthanum is widely used in numerous modern technologies and applications, and its intense usage results in increasing discharges into the environment, with potentially deleterious consequences to earthlings. Therefore, we exposed the important food resource and powerful monitoring tool Manila clam to two environmentally relevant concentrations of La (0.3 µg L^-1 and 0.9 µg L^-1) for 6 days, through water, to assess the bioaccumulation pattern in the gills, digestive gland, and remaining body. The La bioaccumulation was measured after 1 (T1), 2 (T2), and 6 (T6) days of exposure. Lanthanum was bioaccumulated after 2 days, and the levels increased in all tissues in a dose-dependent manner. When exposed to 0.3 µg L^-1, the enrichment factor pattern was gills > body > digestive gland. However, when exposed to 0.9 µg L^-1, the pattern appears to change to gills > digestive gland > body. Tissue portioning appears to be linked with exposed concentration: In higher exposure levels, digestive gland seems to gain importance, probably associated with detoxification mechanisms. Here, we describe for the first time La bioaccumulation in these different tissues in a bivalve species. Future studies dealing with the bioaccumulation and availability of La should connect them with additional water parameters (such as temperature, pH, and major cations).

Effects of the antineoplastic drug cyclophosphamide on the biochemical responses of the mussel Mytilus galloprovincialis under different temperatures

Cyclophosphamide (CP) is an antineoplastic drug widely used in chemotherapy treatments with high consumption rates and that has been detected in the aquatic environment. After being released into the aquatic environment, CP may cause adverse effects on aquatic organisms since antineoplastics are well-known cytotoxic, genotoxic, mutagenic and teratogenic drugs. Moreover, predicted environmental changes, such as the temperature rising, may alter the impacts caused by CP on organisms. Thus, the present study aimed to assess the effects caused by CP chronic exposure in the mussel Mytilus galloprovincialis, under actual and predicted warming scenarios. Organisms were exposed for 28 days to different concentrations of CP (10, 100, 500 and 1000 ng/L) at control (17 ± 1.0 °C) and increased (21 ± 1.0 °C) temperatures. Biochemical responses related to metabolic capacity, energy reserves, oxidative stress and neurotoxicity were assessed. The results showed that the organisms were able to maintain their metabolic capacity under all exposure conditions. However, their antioxidant defense mechanisms were activated mostly at higher CP concentrations being able to prevent cellular damage, even under the warming scenario. Overall, the present findings suggest that temperature rise may not alter the impacts of CP towards M. galloprovincialis.

Effects of temperature on caffeine and carbon nanotubes co-exposure in Ruditapes philippinarum

In the marine environment, organisms are exposed to a high and increasing number of different contaminants that can interact among them. In addition, abiotic factors can change the dynamics between contaminants and organisms, thus increasing or even decreasing the toxic effect of a particular compound. In this study, the effects of caffeine (CAF) and functionalized multi-walled carbon nanotubes (f-MWCNTs) induced in the clam Ruditapes philippinarum were evaluated, acting alone and in combination (MIX), under two temperature levels (18 and 21 °C). To assess the impact of such compounds, their interaction and the possible influence of temperature, biochemical and histopathological markers were investigated. The effects of f-MWCNTs and caffeine appear to be clearly negative at the control temperature, with lower protein content in contaminated clams and a significant decrease in their metabolism when both pollutants were acting in combination. Also, at control temperature, clams exposed to pollutants showed increased antioxidant capacity, especially when caffeine was acting alone, although cellular damages were still observed at CAF and f-MWCNTs treatments. Increased biotransformation capacity at 18 °C and MIX treatment may explain lower caffeine concentration observed. At increased temperature differences among treatments were not so evident as at 18 °C, with a similar biological pattern among contaminated and control clams. Higher caffeine accumulation at MIX treatment under warming conditions may result from clams' inefficient biotransformation capacity when exposed to increased temperatures.

Oxidative stress, metabolic activity and mercury concentrations in Antarctic krill Euphausia superba and myctophid fish of the Southern Ocean

Indicators of oxidative stress and metabolic capacity are key factors in understanding the fitness of wild populations. In the present study, these factors were evaluated in the pelagic Southern Ocean taxa Antarctic krill (Euphausia superba) and myctophid fish (Electrona antarctica, Gymnoscopelus braueri and G. nicholsi) to establish a baseline record for future studies. Mercury (Hg) concentrations were also analysed to evaluate its potential impacts on species biochemical performance. E. superba had higher metabolic activity than most of the myctophid species, which may explain the comparatively lower energy reserves found in the former. The activity of antioxidant enzymes showed, generally, a lower level in E. superba than in the myctophid species. The lack of any relationship between Hg concentrations and organisms' antioxidant and biotransformation defence mechanisms indicate that levels of Hg accumulated in the studied species were not high enough to affect their biochemical processes adversely.

Occurrence and risk assessment of pharmaceuticals and cocaine around the coastal submarine sewage outfall in Guarujá, São Paulo State, Brazil

The aim of this study was to screen and quantify 23 pharmaceutical compounds (including illicit drugs), at two sampling points near the diffusers of the Guarujá submarine outfall, State of São Paulo, Brazil. Samples were collected in triplicate during the high (January 2018) and low (April 2018) seasons at two different water column depths (surface and bottom). A total of 10 compounds were detected using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Caffeine (42.3-141.0 ng/L), diclofenac (3.6-85.7 ng/L), valsartan (4.7-14.3 ng/L), benzoylecgonine (0.3-1.7 ng/L), and cocaine (0.3-0.6 ng/L) were frequently detected (75% occurrence). Orphenadrine (0.6-3.0 ng/L) and atenolol (0.1-0.3 ng/L), and acetaminophen (1.2-1.4 ng/L) and losartan (0.7-3.4 ng/L), were detected in 50% and 25% of the samples, respectively. Only one sample (12.5%) detected the presence of carbamazepine (< 0.001-0.1 ng/L). Unexpectedly a lower frequency of occurrence and concentration of these compounds occurred during the summer season, suggesting that other factors, such as the oceanographic and hydrodynamic regimes of the study area, besides the population rise, should be taken into account. Caffeine presented concentrations above the surface water safety limits (0.01 μg/L). For almost all compounds, the observed concentrations indicate nonenvironmental risk for the aquatic biota, except for caffeine, diclofenac, and acetaminophen that showed low to moderate ecological risk for the three trophic levels tested.

Indicator Compounds Representative of Contaminants of Emerging Concern (CECs) Found in the Water Cycle in the United States

The presence of contaminants of emerging concern (CECs) in the aquatic environment has recently become a global issue. The very large number of CECs reported in the literature makes it difficult to interpret potential risks as well as the removal efficiencies, especially for the more recalcitrant compounds. As such, there is a need for indicator compounds that are representative of CECs detected in systems worldwide. In an effort to develop such a list, five criteria were used to address the potential for applying indicator compounds; these criteria include usage, occurrence, resistance to treatment, persistence, and physicochemical properties that shed light on the potential degradability of a class of compounds. Additional constraints applied included the feasibility of procuring and analyzing compounds. In total, 22 CECs belonging to 13 groups were selected as indicator compounds. These compounds include acetaminophen and ibuprofen (analgesic); erythromycin, sulfamethoxazole, and trimethoprim (antibiotics); diazepam and fluoxetine (antidepressants); carbamazepine (antiepileptic); atenolol and propranolol (β-blockers); gemfibrozil (blood lipid regulator); tris(2-chloroethyl)phosphate (TCEP) (fire retardant); cotinine (nicotine metabolite); atrazine, metolachlor, and N,N-diethyl-meta-toluamide (DEET) (pesticides); 17β-estradiol and cholesterol (steroids); caffeine (psychomotor stimulant); perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) (surfactants); and iopromide (X-ray contrast agent). These thirteen groups of compounds represent CECs with the greatest resistance to treatment processes, most persistent in surface waters, and detected with significant frequency throughout the water cycle. Among the important implications of using indicator compounds are the ability to better understand the efficacy of treatment processes as well as the transport and fate of these compounds in the environment.

Chronic exposure to PPCPs mixture at environmentally relevant concentrations (ERCs) altered carbohydrate and lipid metabolism through gut and liver toxicity in zebrafish

Pharmaceuticals and personal care products (PPCPs) have been widely distributed and posed ecotoxicological risks in the aquatic environment. This study aims to evaluate the toxic effects after chronic exposure to PPCPs mixture at the environment relevant concentrations (ERCs). Our results indicated that PPCPs induced serious metabolic effects by disturbing the carbohydrate and lipid metabolism pathways. Chronic exposure caused a significant reduction in the hepatosomatic index (HSI), the gut weight ratios, and histological alterations in liver and gut tissues. Further, exposure to the combined PPCPs disrupted the carbohydrate metabolism via significant upregulation of hk1, gk, pck1, and insr genes. The lipid metabolism was affected with higher ppars expression levels that increased the fatty acid β-oxidation and ultimately decreased the lipidogenesis. Moreover, the altered responses of the insulin growth factor (IGF) pathway more in male gut tissue than that of female revealed sex-dependent disturbance in the gut homeostasis induced by PPCPs mixture. In conclusion, chronic exposure to PPCPs mixtures at ERCs can induce developmental effects and metabolic dysfunction in both male and female fish. The consumption and environmental disposal of these PPCPs should be regulated to ensure ecological health and environmental safety.

Can ocean warming alter sub-lethal effects of antiepileptic and antihistaminic pharmaceuticals in marine bivalves?

The negative effects induced in marine organisms by Climate Change related abiotic factors consequences, namely ocean warming, are well-known. However, few works studied the combined impacts of ocean warming and contaminants, as pharmaceutical drugs. Carbamazepine (CBZ) and cetirizine (CTZ) occur in the marine environment, showing negative effects in marine organisms. This study aimed to evaluate the impacts of ocean warming on the effects of CBZ and CTZ, when acting individually and combined (drug vs drug), in the edible clam Ruditapes philippinarum. For that, drugs concentration, bioconcentration factors and biochemical parameters, related with clam's metabolic capacity and oxidative stress, were evaluated after 28 days exposure to environmentally relevant scenarios of these stressors. The results showed limited impacts of the drugs (single and combined) at control and warming condition. Indeed, it appeared that warming improved the oxidative status of contaminated clams (higher reduced to oxidized glutathione ratio, lower lipid peroxidation and protein carbonylation levels), especially when both drugs were combined. This may result from clam's defence mechanisms activation and reduced metabolic capacity that, respectively, increased elimination and limited production of reactive oxygen species. At low stress levels, defence mechanisms were not activated which resulted into oxidative stress. The present findings highlighted that under higher stress levels clams may be able to activate defence strategies that were sufficient to avoid cellular damages and loss of redox homeostasis. Nevertheless, low concentrations were tested in the present study and the observed responses may greatly change under increased pollution levels or temperatures. Further research on this topic is needed since marine heat waves are increasing in frequency and intensity and pollution levels of some pharmaceuticals are also increasing in coastal systems.

Effects of Carbamazepine in Bivalves: A Review

Carbamazepine (CBZ) is among the ten most frequent pharmaceuticals that occur in the aquatic systems, with known effects on inhabiting organisms, including bivalves. Bivalves are important species in coastal ecosystems, often exhibiting a dominant biomass within invertebrate communities. These organisms play a major role in the functioning of the ecosystem and particularly in food webs (as suspension-feeders) and represent a significant fraction of the fisheries resource. They also have strong interactions with the environment, water and sediment and are considered good bioindicator species. The present paper reviews the known literature on the impacts of CBZ in biological endpoints of marine bivalves exposed to environmentally and non-environmentally relevant concentrations, highlighting differences in terms of biological responses, associated with exposure period, concentrations tested, and species used. Overall, the literature available showed that CBZ induces individual and sub-individual effects in marine bivalves (adults and life stages) and the most common effect reported was the induction of oxidative stress.

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.

Impacts of salicylic acid in Mytilus galloprovincialis exposed to warming conditions

While many studies have been conducted on drug-inducing alterations in the aquatic environment, little is known about their interaction with climate change, such as rising temperatures. To increase knowledge on this topic, Mytilus galloprovincialis mussels were exposed to two different temperatures 17 ± 1 °C (control) and 21 ± 1 °C in the absence and presence of salicylic acid (SA) (4 mg/L) for 28 days. Salicylic acid in the water and tissues was measured and its impact reported through biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen (GLY), protein (PROT) and lipids (LIP) contents), oxidative stress markers (activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), glutathione balance between the reduced and the oxidized forms (GSH/GSSG), and damage to membrane lipids (lipid peroxidation - LPO). The mussels responded differently if the stresses imposed were single or combined, with greater impacts when both stressors were acting together. Contaminated mussels exposed to high temperatures were unable to increase their metabolic capacity to restore their defence mechanisms, reducing the expenditure of LIP. In the presence of SA and increased temperature antioxidant defences respond differently, with higher SOD levels and inhibition of CAT. The present study highlights not only the negative impact of warming and SA, but especially how temperature increase will promote the impact of SA in M. galloprovincialis, which under predicted climate change scenarios may greatly impair population maintenance and ecosystem biodiversity.

Assessing pharmaceutical contamination along the Mediterranean and Red Sea coasts of Israel: Ascidians (Chordata, Ascidiacea) as bioindicators

Global increase in the use of pharmaceutically-active compounds (PhACs), and their insufficient removal in wastewater treatment plants, have resulted in their continuous release into the marine environment. We investigated the use of the solitary ascidians Herdmania momus, Microcosmus exasperatus, and Styela plicata as bioindicators of three common PhACs in the Israeli coastal waters: Bezafibrate, carbamazepine and diclofenac. Both the Mediterranean and the Red-Sea coasts were found contaminated with PhACs, detected at all 11 sampling sites, with four sites contaminated with all three studied PhACs. Diclofenac was most frequent, present in nine of the 11 sites with concentrations reaching 51.9 ng/g of dry weight sample (dw). Bezafibrate and carbamazepine reached concentrations of 47.8 ng/g dw and 14.3 ng/g dw, respectively. The alarming detection of such high concentrations of PhACs in ascidians along Israel's coasts demonstrates both the extent of PhACs contamination in the region, and the potential of ascidians as bioindicators, and emphasizes the urgent need for additional research into PhAC contamination sources and effects.

Potential of environmental concentrations of the musks galaxolide and tonalide to induce oxidative stress and genotoxicity in the marine environment

Polycyclic musk compounds have been identified in environmental matrices (water, sediment and air) and in biological tissues in the last decade, yet only minimal attention has been paid to their chronic toxicity in the marine environment. In the present research, the clams Ruditapes philippinarum were exposed to 0.005, 0.05, 0.5, 5 and 50 μg/L of the fragrances Galaxolide® (HHCB) and Tonalide® (AHTN) for 21 days. A battery of biomarkers related with xenobiotics biotransformation (EROD and GST), oxidative stress (GPx, GR and LPO) and genotoxicity (DNA damage) were measured in digestive gland tissues. HHCB and AHTN significantly (p < 0.05) induced EROD and GST enzymatic activities at environmental concentrations. Both fragrances also induced GPx activity. All concentrations of both compounds induced an increase of LPO and DNA damage on day 21. Although these substances have been reported as not acutely toxic, this study shows that they might induce oxidative stress and genotoxicity in marine organisms.

The Role of Temperature on the Impact of Remediated Water towards Marine Organisms

Marine organisms are frequently exposed to pollutants, including trace metals, derived from natural and anthropogenic activities. In order to prevent environmental pollution, different approaches have been applied to remove pollutants from waste water and avoid their discharge into aquatic systems. However, organisms in their natural aquatic environments are also exposed to physico-chemical changes derived from climate change-related factors, including temperature increase. According to recent studies, warming has a negative impact on marine wildlife, with known effects on organisms physiological and biochemical performance. Recently, a material based on graphene oxide (GO) functionalized with polyethyleneimine (PEI) proved to be effective in the remediation of mercury (Hg) contaminated water. Nevertheless, no information is available on the toxic impacts of such remediated water towards aquatic systems, neither under actual nor predicted temperature conditions. For this, the present study assessed the toxicity of seawater, previously contaminated with Hg and remediated by GO-PEI, using the clam species Ruditapes philippinarum exposed to actual and a predicted temperature conditions. The results obtained demonstrated that seawater contaminated with Hg and/or Hg+GO-PEI induced higher toxicity in clams exposed to 17 and 22 °C compared to organisms exposed to remediated seawater at the same temperatures. Moreover, similar histological and biochemical results were observed between organisms exposed to control and remediated seawater, independently of the temperatures (17 and 21 °C), highlighting the potential use of GO-PEI to remediate Hg from seawater without significant toxicity issues to the selected marine species.

New insights on the impacts of e-waste towards marine bivalves: The case of the rare earth element Dysprosium

With the technological advances and economic development, the multiplicity and wide variety of applications of electrical and electronic equipment have increased, as well as the amount of end-of-life products (waste of electrical and electronic equipment, WEEE). Accompanying their increasing application, there is an increasing risk to aquatic ecosystems and inhabiting organisms. Among the most common elements present in WEEE are rare earth elements (REE) such as Dysprosium (Dy). The present study evaluated the metabolic and oxidative stress responses of mussels Mytilus galloprovincialis exposed to an increasing range of Dy concentrations, after a 28 days experimental period. The results obtained highlighted that Dy was responsible for mussel's metabolic increase associated with glycogen expenditure, activation of antioxidant and biotransformation defences and cellular damage, with a clear loss of redox balance. Such effects may greatly impact mussel's physiological functions, including reproduction capacity and growth, with implications for population conservation. Overall the present study pointed out the need for more research on the toxic impacts resulting from these emerging pollutants, especially towards marine and estuarine invertebrate species.

Metabolomics approach reveals disruption of metabolic pathways in the marine bivalve Mytilus galloprovincialis exposed to a WWTP effluent extract

Conventional wastewater treatment plants (WWTPs) discharge a highly diverse range of organic contaminants in aquatic environments, including marine waters. The health of marine ecosystems could be threatened by contaminants release. Environmental metabolomics can be helpful to assess the effects of multi-contamination on marine organisms without any a priori information since it is able to provide meaningful information on the biochemical response of organisms to a stress. The aim of the present study was to evaluate the potential of metabolomics to highlight key metabolites disrupted by a WWTP effluent extract exposure and then elucidate the biological effects of such exposure on Mediterranean mussels (Mytilus galloprovincialis). Exposed male mussels showed numerous metabolites altered in response to WWTP effluent exposure. The highlighted metabolites belong mainly to amino acids metabolism (e.g. tyrosine, phenylalanine, leucine, proline, etc.), neurohormones (dopamine and a serotonin metabolite), purine and pyrimidine metabolism (e.g. adenosine, adenine, guanine, uracil etc.), citric acid cycle intermediates (e.g. malate, fumarate), and a component involved in oxidative stress defense (oxidized glutathione). Modulation of these metabolites could reflect the alteration of several biological processes such as energy metabolism, DNA and RNA synthesis, immune system, osmoregulation, byssus formation and reproduction, which may lead to a negative impact of organism fitness. Our study provided further insight into the effects of WWTP effluents on marine organisms.

Toxicological effects of the rare earth element neodymium in Mytilus galloprovincialis

The wide range of applications of rare earth elements (REE) is leading to their occurrence in worldwide aquatic environments. Among the most popular REE is Neodymium (Nd), being widely used in permanent magnets, lasers, and glass additives. Neodymium-iron-boron (NdFeB) magnets is the main application of Nd since they are used in electric motors, hard disk drives, speakers and generators for wind turbines. Recent studies have already evaluated the toxic potential of different REE, but no information is available on the effects of Nd towards marine bivalves. Thus, the present study evaluated the biochemical alterations caused by Nd in the mussel Mytilus galloprovincialis exposed to this element for 28 days. The results obtained clearly demonstrated that Nd was accumulated by mussels, leading to mussel's metabolic capacity increase and GLY expenditure, in an attempt to fuel up defense mechanisms. Antioxidant and biotransformation defenses were insufficient in the elimination of ROS excess, resulting from the presence of Nd and increased electron transport system activity, which caused cellular damages (measured by lipid peroxidation) and loss of redox balance (assessed by the ratio between reduced and oxidized glutathione). The results obtained clearly highlight the potential toxicity of REEs and, in particular of Nd, with impacts at cellular level, which may have consequences in mussel's survival, growth and reproduction, affecting mussel's population.

Monitoring pharmaceuticals in the aquatic environment using enzyme-linked immunosorbent assay (ELISA)-a practical overview

The presence of pharmaceuticals, which are considered as contaminants of emerging concern, in natural waters is currently recognized as a widespread problem. Monitoring these contaminants in the environment has been an important field of research since their presence can affect the ecosystems even at very low levels. Several analytical techniques have been developed to detect and quantify trace concentrations of these contaminants in the aquatic environment, namely high-performance liquid chromatography, gas chromatography, and capillary electrophoresis, usually coupled to different types of detectors, which need to be complemented with time-consuming and costly sample cleaning and pre-concentration procedures. Generally, the enzyme-linked immunosorbent assay (ELISA), as other immunoassay methodologies, is mostly used in biological samples (most frequently urine and blood). However, during the last years, the number of studies referring the use of ELISA for the analysis of pharmaceuticals in complex environmental samples has been growing. Therefore, this work aims to present an overview of the application of ELISA for screening and quantification of pharmaceuticals in the aquatic environment, namely in water samples and biological tissues. The experimental procedures together with the main advantages and limitations of the assay are addressed, as well as new incomes related with the application of molecular imprinted polymers to mimic antibodies in similar, but alternative, approaches. Graphical Abstract.

The influence of climate change related factors on the response of two clam species to diclofenac

Diclofenac (DIC) is one of the non-steroidal anti-inflammatory drugs (NSAID) with higher consumption rates, used in both human and veterinary medicine. Previous studies already demonstrated the presence of this drug in aquatic environments and adverse effects towards inhabiting organisms. However, with the predictions of ocean acidification and warming, the impacts induced by DIC may differ from what is presently known and can be species-dependent. Thus, the present study aimed to comparatively assess the effects caused by DIC in the clams Ruditapes philippinarum and Ruditapes decussatus and evaluate if these impacts were influenced by pH and temperature. For this, organisms were acclimated for 30 days at two different temperature and pH (control conditions: pH 8.1, 17 °C; climate change forecasted scenario: pH 7.7, 20 °C) in the absence of drugs (experimental period I) followed by 7 days exposure under the same water physical parameters but in absence or presence of the pharmaceutical drug (at 1 μg/L, experimental period II). Biochemical responses covering metabolic capacity, oxidative stress and damage-related biomarkers were contrasted in clams at the end of the second experimental period. The results showed that under actual conditions, R. philippinarum individuals exposed to DIC presented enhanced antioxidant activities and reduced their respiration rate compared with non-contaminated clams. When exposed to the predicted climate change conditions, a similar response was observed in contaminated clams, but in this case clams increased their metabolic activities probably to fight the stress caused by the combination of both stressors. When R. decussatus was exposed to DIC, even at actual pH and temperature conditions, their antioxidant defences were also elevated but their baseline enzymatic activities were also naturally higher in respect to R. philippinarum. Although clams may use different strategies to prevent DIC damage, both clam species showed under low pH and high temperature limited oxidative stress impacts in line with a lower DIC bioaccumulation. The present findings reveal that predicted climate change related factors may not enhance the impacts of DIC in Ruditapes clams in a species-dependent manner although both displayed particular mechanisms to face stress.

Carbamazepine, cadmium chloride and polybrominated diphenyl ether-47, synergistically modulate the expression of antioxidants and cell cycle biomarkers, in the marine fish cell line SAF-1

A wide range of contaminants, industrial by-products, plastics, and pharmaceutics belonging to various categories, have been found in sea water. Although these compounds are detected at concentrations that might be considered as sub-lethal, under certain conditions they could act synergistically producing unexpected effects in term of toxicity or perturbation of biochemical markers leading to standard pathway. In this study, the Sparus aurata fibroblast cell line SAF-1, was exposed to increasing concentrations of carbamazepine (CBZ), polybrominated diphenyl ether 47 (BDE-47) and cadmium chloride (CdCl₂) until 72 h, to evaluate the cytotoxicity and the expression of genes related to antioxidant defense, cell cycle and energetic balance. In general, both vitality and gene expression were affected by the exposure to the different toxicants, in terms of antioxidant defense and cell cycle control, showing the most significant effects in cells exposed to the mixture of the three compounds, respect to the single compounds separately. The synergic effect of the compounds on the analyzed biomarkers, underlie the potential negative impact of the contaminants on health of marine organisms.

Toxic impacts induced by Sodium lauryl sulfate in Mytilus galloprovincialis

Pharmaceuticals and personal care products (PPCPs) are continuously dispersed into the environment, as a result of human and veterinary use, reaching aquatic coastal systems and inhabiting organisms. However, information regarding to toxic effects of these compounds towards marine invertebrates is still scarce, especially in what regards to metabolic capacity and oxidative status alterations induced in bivalves after chronic exposure. In the present study, the toxic impacts of Sodium lauryl sulfate (SLS), an anionic surfactant widely used as an emulsifying cleaning agent in household and cosmetics, were evaluated in the mussel Mytilus galloprovincialis, after exposure for 28 days to different concentrations (0.0; 0.5; 1.0; 2.0 and 4.0 mg/L). For this, effects on mussels respitation rate, metabolic capacity and oxidative status were evaluated. The obtained results indicate a significant decrease on mussel's respiration rate after exposure to different SLS concentrations, an alteration that was accompanied by a decrease of bioconcentration factor along the increasing exposure gradient, especially at the highest exposure concentration. Nonetheless, the amount of SLS accumulated in organisms originated alterations in mussel's metabolic performance, with higher metabolic capacity up to 2.0 mg/L followed by a decrease at the highest tested concentration (4.0 mg/L). Mussels exposed to SLS revealed limited antioxidant defense mecanhisms but cellular damage was only observed at the highest exposure concentration (4.0 mg/L). In fact, up to 2.0 mg/L of SLS limited toxic impacts were observed, namely in terms of oxidative stress and redox balance. However, since mussel's respiration rate was greatly affected by the presence of SLS, the present study may highlight the potential threat of SLS towards marine bivalves, limiting their filtration capacity and, thus, affecting their global physiological development (including growth and reproduction) and ultimely their biochemical performance (afecting their defense capacity towards stressful conditons).

Biochemical and physiological responses induced in Mytilus galloprovincialis after a chronic exposure to salicylic acid

A vast variety of substances currently reaches the aquatic environment, including newly developed chemicals and products. Lack of appropriate analytical methods for trace determinations in aquatic ecosystem compartments and lack of information regarding their toxicity explains existing regulation gaps. However, suspicion of their toxicity assigned them as Contaminants of Emerging Concern (CECs). Among CECs are Pharmaceuticals including Salicylic Acid (SA), which is the active metabolite of acetylsalicylic acid (ASA; aspirin). The aim of the present study was to evaluate the potential effects of SA on the mussel Mytilus galloprovincialis. For this, organisms were exposed for 28 days to different concentrations of SA (0.005; 0.05; 0.5 and 5 mg/L), resembling low to highly polluted sites, after which different physiological and biochemical parameters were evaluated to assess organism's respiration rate, neurotoxic, metabolic and oxidative stress status. Our results clearly showed that SA strongly reduced the respiration capacity of mussels. Also, SA inhibited the activity of superoxide dismutase (SOD) and catalase (CAT) enzymes, but increased the activity of glutathione peroxidase (GPx) and glutathione-S-transferases (GSTs), which prevented the occurrence of lipid peroxidation (LPO). Nevertheless, oxidative stress was confirmed by the strong decrease of the ratio between reduce glutathione (GSH) and oxidized (GSSG) glutathione in contaminated mussels. Moreover, neurotoxicity was observed in mussels exposed to SA. Overall, this study demonstrates the metabolic, neurotoxic and oxidative stress impacts of SA in M. galloprovincialis, which may result in negative consequences at the population level.

Biomarkers responses in Manila clam, Ruditapes philippinarum after single and combined exposure to mercury and benzo[a]pyrene

Physiological and biochemical responses in bivalves exposed to pollutants have proved a valuable tool to assess the health of organisms in aquatic ecosystems. The single and combined effects of mercury (Hg²⁺, 2 and 10 μg/L) and benzo[a]pyrene (BaP, 3 μg/L) on physiological and biochemical biomarkers in Manila clam, Ruditapes philippinarum were evaluated. Results showed that significant higher oxygen consumption (OR) and ammonia-N excretion rates (NR) together with significant lower ingestion rates (IR) were observed for the 10 μg/L Hg²⁺ or 3 μg/L BaP treatments compared to controls (P < 0.05). However, clam NR decreased significantly in response to the binary mixtures of 10 μg/L Hg²⁺ and 3 μg/L BaP (P < 0.05). Moreover, the levels of superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferases (GSTs), glutathione (GSH), acetylcholinesterase (AChE) and malondialdehyde (MDA) in the hepatopancreas of clams were induced substantially, whereas glycogen (GLY) contents were suppressed dramatically after Hg²⁺ and BaP exposure. Additionally, the integrated biomarker response (IBR) values measured showed significant increases in combination treatments and they were much higher than that in the Hg²⁺ treatment. This study will provide further information on the defense mechanism in the Manila clam after exposure to marine pollutants and may help evaluate the quality of the aquatic environment.

Evidences of metabolic alterations and cellular damage in mussels after short pulses of Ti contamination

Mytilus galloprovincialis mussels were exposed to seawater contaminated with Ti. Initial concentrations were 4.1, 32, and 66 μg L^-1 that declined during the first 24 h of the experiments, and after 48 h values were <2 μg L^-1. Experiments were run in triplicate, under constant salinity and temperature. Mussels were fed every two days, and water renewed every seven days and Ti concentrations re-stabilized. During the first 28 days of experimental period, mussels were exposed to four short pulses of contamination, followed by few days of low Ti concentration between weekly contamination renewals. Then mussels were exposed to additional 14-day exposure to Ti uncontaminated seawater. Only residual Ti concentrations were measured in mussels' whole soft tissue after the four pulses of Ti contamination, indicating low Ti accumulation by the organisms. Nevertheless, the biomarkers related to mussels' metabolic capacity (electron transport system activity, ETS), oxidative damage (lipid peroxidation, LPO and reduced glutathione content, GSH), and defense mechanisms (antioxidant and biotransformation enzymes) evidenced the impact of Ti during the 28 days of experimental period. The biomarkers that better indicated the recovery of mussels' biochemical performance were the ETS, LPO, GSH, and the antioxidant enzyme glutathione peroxidase (GPx). LPO was the prime indicator among the analyzed biochemical responses. Organisms appear to hold coping mechanisms to lower the damage induced by Ti, and to recover, albeit the 14 days period of exposure to uncontaminated seawater following the four Ti pulses were not enough for full recovery, as evidenced by results on LPO levels and GSH concentrations. Despite the low solubility of Ti in seawater, the toxicity of this element to a model marine organism was demonstrated.

Bioenergetics-adverse outcome pathway: Linking organismal and suborganismal energetic endpoints to adverse outcomes

Adverse outcome pathways (AOPs) link toxicity across levels of biological organization, and thereby facilitate the development of suborganismal responses predictive of whole-organism toxicity and provide the mechanistic information necessary for science-based extrapolation to population-level effects. Thus far AOPs have characterized various acute and chronic toxicity pathways; however, the potential for AOPs to explicitly characterize indirect, energy-mediated effects from toxicants has yet to be fully explored. Indeed, although exposure to contaminants can alter an organism's energy budget, energetic endpoints are rarely incorporated into ecological risk assessment because there is not an integrative framework for linking energetic effects to organismal endpoints relevant to risk assessment (e.g., survival, reproduction, growth). In the present analysis, we developed a generalized bioenergetics-AOP in an effort to make better use of energetic endpoints in risk assessment, specifically exposure scenarios that generate an energetic burden to organisms. To evaluate empirical support for a bioenergetics-AOP, we analyzed published data for links between energetic endpoints across levels of biological organization. We found correlations between 1) cellular energy allocation and whole-animal growth, and 2) metabolic rate and scope for growth. Moreover, we reviewed literature linking energy availability to nontraditional toxicological endpoints (e.g., locomotor performance), and found evidence that toxicants impair aerobic performance and activity. We conclude by highlighting current knowledge gaps that should be addressed to develop specific bioenergetics-AOPs. Environ Toxicol Chem 2019;38:27-45. © 2018 SETAC.

Effects of water turbidity and different temperatures on oxidative stress in caddisfly (Stenopsyche marmorata) larvae

Anthropogenic water turbidity derived from suspended solids (SS) is caused by reservoir sediment management practices such as drawdown flushing. Turbid water induces stress in many aquatic organisms, but the effects of turbidity on oxidative stress responses in aquatic insects have not yet been demonstrated. Here, we examined antioxidant responses, oxidative damage, and energy reserves in caddisfly (Stenopsyche marmorata) larvae exposed to turbid water (0 mg SS L^-1, 500 mg SS L^-1, and 2000 mg SS L^-1) at different temperatures. We evaluated the combined effects of turbid water and temperature by measuring oxidative stress and using metabolic biomarkers. No turbidity level was significantly lethal to S. marmorata larvae. Moreover, there were no significant differences in antioxidant response or oxidative damage between the control and turbid water treatments at a low temperature (10 °C). However, at a high temperature (25 °C), turbid water modulated the activity of the antioxidant enzymes superoxide dismutase and catalase and the oxygen radical absorbance capacity as an indicator of the redox state of the insect larvae. Antioxidant defenses require energy, and high temperature was associated with low energy reserves, which might limit the capability of organisms to counteract reactive oxygen species. Moreover, co-exposure to turbid water and high temperature caused fluctuation of antioxidant defenses and increased the oxidative damage caused by the production of reactive oxygen species. Furthermore, the combined effect of high temperature and turbid water on antioxidant defenses and oxidative damage was larger than the individual effects. Therefore, our results demonstrate that exposure to both turbid water and high temperature generates additive and synergistic interactions causing oxidative stress in this aquatic insect species.

Effects of single and combined exposure of pharmaceutical drugs (carbamazepine and cetirizine) and a metal (cadmium) on the biochemical responses of R. philippinarum

In the aquatic environment, organisms are exposed to complex mixtures of contaminants which may alter the toxicity profile of each compound, compared to its toxicity alone. Pharmaceutical drugs (e.g. carbamazepine (CBZ) and cetirizine (CTZ)) and metals (e.g. cadmium (Cd)) are among those contaminants that co-occur in the environment. However, most studies concerning their toxicity towards aquatic species are based on single exposure experiments. Thus, the present study aimed to evaluate single and combined effects of Cd and CBZ or CTZ (single conditions: Cd, CTZ, CBZ; combined conditions: CTZ + Cd, CBZ + Cd) on biomarkers related to oxidative stress and energy metabolism in the edible clam Ruditapes philippinarum, by exposing the organisms for 28 days to environmentally relevant concentrations of these contaminants. The biomarkers studied were: i) the electron transport system activity, protein and glycogen contents (indicators of organisms' metabolic status and energy reserves); ii) lipid peroxidation and the ratio between reduced and oxidized glutathione (indicators of oxidative stress); iii) superoxide dismutase and catalase activities (enzymes indicators of antioxidant defence) and iv) activity of glutathione S-transferases (family of enzymes indicators of biotransformation capacity). Results obtained showed that the uptake of Cd and CBZ was not affected by the combined presence of the contaminants. However, for CTZ, the uptake was higher in the presence than in the absence of Cd. Concerning toxicity data, in general, the combined exposures (CTZ + Cd, CBZ + Cd) had lower biological effects than the contaminants alone. Nevertheless, our data showed that despite the low concentrations tested, they were enough to exert biological effects that differed between single and combined treatments, evidencing the need to conduct more co-exposure studies to increase the environmental relevance of the gathered data.

Effects of carbamazepine and cetirizine under an ocean acidification scenario on the biochemical and transcriptome responses of the clam Ruditapes philippinarum

Several works evaluated the toxicity of pharmaceutical drugs and climate related changes in invertebrates but few explored the combined effects of both stressors, namely considering their mode of action (MoA). Carbamazepine (CBZ) and cetirizine (CTZ) are pharmaceutical drugs detected in the environment and the toxicity derived from the combined effects of these drugs with ocean acidification (OA) is poorly explored. Thus, the present study investigated the biochemical parameters related to an oxidative stress response and the transcription of genes related to the MoA of CBZ (1.0 μg/L) and CTZ (0.6 μg/L) in the clam Ruditapes philippinarum chronically exposed (28 days) to control (7.8) and low (7.5) pH conditions. The results obtained showed that despite the clams accumulated both drugs, at low pH the clams exposed to CTZ decreased drug concentration and BCF values (CTZ uptake: 2.0 ± 0.5 ng/g fresh weight; BCF: 3.8 ± 0.9) in comparison with clams exposed to control pH (CTZ uptake: 2.9 ± 0.3 ng/g fresh weight; BCF: 5.5 ± 0.6). No oxidative stress was induced by the exposure to CBZ or CTZ at each pH level, but the transcription of several genes related with the MoA (neurotransmission, immunity and biomineralization) was altered by low pH, drug exposure and the combination of both stressors. At both pH conditions, CBZ increased the transcription of GABA receptor gene (neurotransmission) and CTZ led to a decrease of Perlucin gene (biomineralization) transcription. The transcription of MyD88 gene (immunity) decreased at low pH (7.5) combined with drug exposure (CBZ or CTZ). Thus, it was highlighted that the interaction of drug exposure and low pH conditions can change bivalves' sensitivity to drugs or alter drugs toxicity.

Environmentally Relevant Concentrations of Carbamazepine Caused Endocrine-Disrupting Effects on Nontarget Organisms, Chinese Rare Minnows (Gobiocypris rarus)

In the present study, Chinese rare minnows (Gobiocypris rarus) were exposed to 1, 10, and 100 μg/L of carbamazepine (CBZ) under flow-through conditions for 28 d. A hepatic-specific custom microarray identified 111 and 71 differentially expressed genes in the livers of females and males, respectively, exposed to 100 μg/L of CBZ (ratio ≥ 2, p ≤ 0.05). The levels of five differentially expressed genes associated with the hypothalamic-pituitary-gonadal (HPG) axis were quantified by qPCR, and the results indicated the feasibility of screening endocrine-disrupting chemicals using a custom microarray. The mRNA levels of genes related to the HPG axis differed significantly in different organs of Chinese rare minnows (p < 0.05). Significant differences were observed in the 11-ketotestosterone and plasma vitellogenin levels in all treatments and in the 17β-estradiol (E2) levels in the 100 μg/L CBZ treatment. In contrast, the gonadosomatic index was significantly higher in females and slightly higher in males without significant differences. A pathological analysis determined that 10 and 100 μg/L of CBZ could lead to ova-testis in males and significantly promoted ovum maturation in females. Therefore, our results demonstrate that environmentally relevant concentrations of CBZ have homologous estrogenic activity and induce reproductive toxicity in Chinese rare minnows.

Toxicological effects of paracetamol on the clam Ruditapes philippinarum: exposure vs recovery

Exposure of wild organisms to anthropogenic substances never follows a definite time-course and pulsed events can often determine biological responses to such chemicals, confounding the interpretation of toxicological data. This is the case of specific chemicals such as pharmaceutical drugs, which are commonly released by sewage systems into sensitive areas, including estuaries. The presence and amount of these chemicals in the wild can be modulated by events such as dilution due to heavy rain, floods, or by varying patterns of domestic water use (daily vs. seasonal). The present study aimed to obtain additional data about the toxicity of paracetamol towards the marine clam species Ruditapes philippinarum, following realistic modes of exposure. Thus, the toxicity assessment was made after an acute exposure to different concentrations of paracetamol, followed by a recovery period. The adopted toxicological endpoints included energy-related parameters (glycogen content, GLY; protein content, PROT; electron transport system activity, ETS), activity of antioxidant and biotransformation enzymes (superoxide dismutase, SOD; glutathione peroxidase, GPx; Glutathione-S-transferases, GSTs), levels of reduced glutathione (GSH), neurotoxicity (cholinesterases activity, ChEs), and indicators of oxidative damage (lipid peroxidation, LPO). The here obtained results showed an increase in SOD and GPx activities after exposure. In organisms exposed to the highest concentration tested it was also possible to observe a significant increase in GSTs activity. However, these alterations in the antioxidant defence system were not able to prevent the occurrence of oxidative stress in exposed organisms. Furthermore, exposure to paracetamol induced neurotoxicity in clams, with a concentration-dependent ChEs inhibition along the exposure concentrations. Exposure to paracetamol also led to an increase of GLY content which resulted from metabolic activity depression along the increasing exposure gradient. In recovering organisms the activities of SOD, GPx and GSTs decreased back towards control values presenting lower values than the ones observed in organisms after acute exposure to paracetamol. No LPO was registered in organisms after the recovery period. In addition, after recovery, clams showed no signs of neurotoxicity, with ChEs activities in previously exposed organisms similar to control clams. After recovery clams seemed to re-establish their metabolic capacity, especially evidenced in clams previously exposed to the highest paracetamol concentration as demonstrated by the increase of ETS activity up to control values. Furthermore, the decrease of GLY content after recovery may indicate that clams increased their metabolic activity and started to use their energetic reserves to re-establish their oxidative status. This set of data shows that an acute exposure to paracetamol can exert deleterious effects that may compromise specific biochemical pathways in sensitive aquatic species, such as R. philippinarum, but organisms can re-establish their biochemical status to control levels after a recovery period.

Physiological and biochemical alterations induced in the mussel Mytilus galloprovincialis after short and long-term exposure to carbamazepine

The bivalve Mytilus galloprovincialis collected in the Ria de Aveiro, was selected to evaluate the acute and chronic effects of carbamazepine (CBZ) at environmentally relevant concentrations. CBZ is an antiepileptic drug widely found in the aquatic environment with toxic effects to inhabiting organisms. However, few studies evaluated the acute and chronic toxicity of this drug. The experiment was performed by exposing mussels to 0.0, 0.3, 3.0, 6.0 and 9.0 CBZ μg/L, for 96 h and 28 days. To assess the toxicity of the drug, a battery of biomarkers related to mussels general physiological health status and oxidative stress was applied. CBZ was quantified in mussel tissues by an Enzyme-Linked Immunosorbent Assay (ELISA). The results obtained show that CBZ did not induce oxidative stress. However, our findings demonstrated that the drug was taken up by mussels even though presenting low bioconcentration factor (BCF) values (up to 2.2). Furthermore, our results demonstrated that after a chronic exposure the physiological parameters, namely the condition and gonadosomatic indices, were negatively affected which may impair organisms' reproductive capacity with consequences to population sustainability.

The impacts of emergent pollutants on Ruditapes philippinarum: biochemical responses to carbon nanoparticles exposure

Multi-walled carbon nanotubes (MWCNTs) are one of the most important carbon Nanoparticles (NPs). The production and use of these NPs are increasing rapidly and, therefore, the need to assess their presence in the environment and associated risks has become of prime importance. Recent studies demonstrated the impacts of different NPs on bivalves, a taxonomic group where species tolerance to anthropogenic stressors, such as pollutants, is widely variable. The Manila clam Ruditapes philippinarum is one of the most commonly used bivalve species in environmental monitoring studies and ecotoxicology tests, however, to our knowledge, no information is available on biochemical alterations on this species due to MWCNTs exposure. Thus, the present study aimed to assess the toxic effects of different MWCNT concentrations (0.01; 0.10 and 1.00mg/L) in R. philippinarum biochemical (energy reserves, metabolic capacity, oxidative status and neurotoxicity) performance, after 28days of exposure. The results obtained revealed that exposure to MWCNTs altered energy-related responses, with higher metabolic capacity and lower glycogen and protein concentrations in clams exposed to these carbon NPs. Moreover, R. philippinarum exposed to MWCNTs showed oxidative stress expressed in higher lipid peroxidation and lower ratio between reduced and oxidized glutathione, despite the activation of defence mechanisms in exposed clams. Additionally, neurotoxicity was observed by inhibition of cholinesterases activity in organisms exposed to MWCNTs. The present study provides valuable information regarding how these emerging pollutans could become a potential risk for the environment and living organisms.