Hediste diversicolor as bioindicator of pharmaceutical pollution: Results from single and combined exposure to carbamazepine and caffeine

The Role of Life Stages in the Sensitivity of Hediste diversicolor to Nanoplastics: A Case Study with Poly(Methyl)Methacrylate (PMMA)

The presence of plastic particles in oceans has been recognized as a major environmental concern. The decrease in particle size increases their ability to directly interact with biota, with particles in the nanometer size range (nanoplastics-NPs) displaying a higher ability to penetrate biological membranes, which increases with the decrease in particle size. This study aimed to evaluate the role of life stages in the effects of poly(methyl)methacrylate (PMMA) NPs on the polychaete Hediste diversicolor, a key species in the marine food web and nutrient cycle. Thus, behavioral (burrowing activity in clean and spiked sediment) and biochemical endpoints (neurotransmission, energy reserves, antioxidant defenses, and oxidative damage) were assessed in juvenile and adult organisms after 10 days of exposure to spiked sediment (between 0.5 and 128 mg PMMA NPs/Kg sediment). Overall, the results show that H. diversicolor is sensitive to the presence of PMMA NPs. In juveniles, exposed organisms took longer to burrow in sediment, with significant differences from the controls being observed at all tested concentrations when the test was performed with clean sediment, whereas in PMMA NP-spiked sediment, effects were only found at the concentrations 8, 32, and 128 mg PMMA NPs/Kg sediment. Adults displayed lower sensitivity, with differences to controls being found, for both sediment types, at 8, 32, and 128 mg PMMA NPs/Kg sediment. In terms of Acetylcholinesterase, used as a marker of effects on neurotransmission, juveniles and adults displayed opposite trends, with exposed juveniles displaying increased activity (suggesting apoptosis), whereas in adults, overall decreased activity was found. Energy-related parameters revealed a generally similar pattern (increase in exposed organisms) and higher sensitivity in juveniles (significant effects even at the lower concentrations). NPs also demonstrated the ability to increase antioxidant defenses (higher in juveniles), with oxidative damage only being found in terms of protein carbonylation (all tested NPs conditions) in juveniles. Overall, the data reveal the potential of PMMA NPs to affect behavior and induce toxic effects in H. diversicolor, with greater effects in juveniles.

Antioxidant Systematic Alteration Was Responsible for Injuries Inflicted on the Marine Blue Mussel Mytilus edulis Following Strontium Exposure

The ionic properties of strontium (Sr), a significant artificial radionuclide in the marine environment, were estimated using a stable nuclide-substituting experimental system under controlled laboratory conditions. The bio-accumulation of Sr and its impacts, as well as any possible hidden mechanisms, were evaluated based on the physiological alterations of the sentinel blue mussel Mytilus edulis. The mussels were exposed to a series of stress-inducing concentrations, with the highest solubility being 0.2 g/L. No acute lethality was observed during the experiment, but sublethal damage was evident. Sr accumulated in a tissue-specific way, and hemolymph was the target, with the highest accumulating concentration being 64.46 µg/g wet weight (ww). At the molecular level, increases in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and changes in ROS components (H2O2, O2-, and -OH) and antioxidant system activity indicated that the redox equilibrium state in hemocytes was disturbed. Furthermore, the rise in the hemocyte micronucleus (MN) rate (4‱ in the high-concentration group) implied DNA damage. At the cellular level, the structures of hemocytes were damaged, especially with respect to lysosomes, which play a crucial role in phagocytosis. Lysosomal membrane stability (LMS) was also affected, and both acid phosphatase (ACP) and alkaline phosphatase (AKP) activities were reduced, resulting in a significant decline in phagocytosis. The hemolymph population structure at the organ level was disturbed, with large changes in hemocyte number and mortality rate, along with changes in component ratios. These toxic effects were evaluated by employing the adverse outcome pathway (AOP) framework. The results suggested that the disruption of intracellular redox homeostasis is a possible explanation for Sr-induced toxicity in M. edulis.

Exploring toxicological interactions in a changing sea: The case of the alkaloids caffeine and caulerpin

The bisindolic alkaloid caulerpin (CAU) is a bioactive compound isolated from green algae of the genus Caulerpa that are highly invasive in the Mediterranean Sea. On the other side, the purine alkaloid caffeine (CAF) is one of the most globally consumed psychoactive substances and a widespread anthropogenic water pollutant. Both compounds display a large panel of biological properties and are well known to accumulate in the tissues of aquatic organisms and, in certain circumstances, co-occur in the human diet. On this premise, the present study aimed to investigate possible synergistic interactions between CAU and CAF by using the bivalve Mytilus galloprovincialis as a model organism. Mussels were exposed to CAF via medium while they were fed with food enriched with CAU. After treatments, biochemical analysis confirmed the toxic potential of CAF, with increased AChE activity and lipid peroxidation. Also, histopathological alterations were observed in the gills and digestive tubules. The NMR-based metabolomics analysis detected higher levels of free amino acids under CAF treatments. Conversely, the food administration of CAU did not affect the above toxicological biomarkers. In addition, we did not observe any cumulative effect between CAF and CAU toward increased cellular damage and neurotoxicity. On the other hand, a possible action of CAU in decreasing CAF toxicity could be hypothesized based on our results. This hypothesis is supported by the activity of CAU as an agonist of peroxisome proliferator-activated receptors (PPARs). PPARs mediate xenobiotic detoxification via cytochromes P450, which is involved in CAF metabolism. Overall, the results obtained not only rule out any cumulative adverse effects of CAF and CAU but also encourage further research to evaluate the possible use of CAU, a compound easily obtained through the valorization of biomass from invasive species, as a food additive to improve the clearance of xenobiotics.

The Impacts of the Multispecies Approach to Caffeine on Marine Invertebrates

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

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

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

Hot and heavy: Responses of ragworms (Hediste diversicolor) to copper-spiked sediments and elevated temperature

Sediment contamination and seawater warming are two major stressors to macrobenthos in estuaries. However, little is known about their combined effects on infaunal organisms. Here we investigated the responses of an estuarine polychaete Hediste diversicolor to metal-contaminated sediment and increased temperature. Ragworms were exposed to sediments spiked with 10 and 20 mg kg^-1 of copper at 12 and 20 °C for three weeks. No considerable changes were observed in the expression of genes related to copper homeostasis and in the accumulation of oxidative stress damage. Dicarbonyl stress was attenuated by warming exposure. Whole-body energy reserves in the form of carbohydrates, lipids and proteins were little affected, but the energy consumption rate increased with copper exposure and elevated temperature indicating higher basal maintenance costs of ragworms. The combined effects of copper and warming exposures were mostly additive, with copper being a weak stressor and warming a more potent stressor. These results were replicable, as confirmed by two independent experiments of similar settings conducted at two different months of the year. This study suggests the higher sensitivity of energy-related biomarkers and the need to search for more conserved molecular markers of metal exposure in H. diversicolor.

Bioconcentration and cellular effects of emerging contaminants in sponges from Maldivian coral reefs: A managing tool for sustainable tourism

Tourism is the main income source for the Maldives, but concurrently, it represents a growing threat to its marine ecosystem. Here, we monitored the bioaccumulation of 15 emerging contaminants (ECs) in the Maldivian reef sponges Spheciospongia vagabunda collected in two resort islands (Athuruga and Thudufushi, Ari Atoll) and an inhabited island (Magoodhoo, Faafu Atoll), and we analysed their impact on different sponge cellular stress biomarkers. Caffeine and the insect repellent DEET were detected in sponges of all the islands, whereas the antibiotic erythromycin and the UV filter 4-methylbenzylidene camphor were found in resort islands only. Although concentrations were approximately a few ng/g d.w., we quantified various induced cellular effects, in particular an increase of the levels of the enzyme glutathione S-transferase involved in cell detoxification. Our results highlight the importance to increase awareness on ECs pollution, promoting the use of more environmental friendly products to achieving the sustainable development goals.

Biochemical, Genotoxic and Histological Implications of Polypropylene Microplastics on Freshwater Fish Oreochromis mossambicus: An Aquatic Eco-Toxicological Assessment

In recent years, polypropylene microplastic has persisted in freshwater ecosystems and biota, forming ever-growing threats. This research aimed to prepare polypropylene microplastics and evaluate their toxicity to the filter feeder Oreochromis mossambicus. In this research, fish were given a dietary supplement of polypropylene microplastics at 100, 500, and 1000 mg/kg for acute (96 h) and sub-acute (14 days) durations to assess toxic effects on liver tissues. FTIR results revealed the presence of polypropylene microplastic in their digestion matter. The ingestion of microplastics in O. mossambicus led to fluctuations in homeostasis, an upsurge in reactive oxygen species (ROS) levels, an alteration in antioxidant parameters, including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and glutathione peroxidase (GPx); a promotion in the oxidation of lipid molecules; and a denaturation in the neurotransmitter enzyme acetylcholinesterase (AChE). Our data indicated that sustained exposure to microplastics (14 days) produced a more severe threat than acute exposure (96 h). In addition, higher apoptosis, DNA damage (genotoxicity), and histological changes were found in the liver tissues of the sub-acute (14 days) microplastics-treated groups. This research indicated that the constant ingestion of polypropylene microplastics is detrimental to freshwater environments and leads to ecological threats.

Biochemical and Behavioural Alterations Induced by Arsenic and Temperature in Hediste diversicolor of Different Growth Stages

Contamination with Arsenic, a toxic metalloid, is increasing in the marine environment. Additionally, global warming can alter metalloids toxicity. Polychaetes are key species in marine environments. By mobilizing sediments, they play vital roles in nutrient and element (including contaminants) cycles. Most studies with marine invertebrates focus on the effects of metalloids on either adults or larvae. Here, we bring information on the effects of temperature increase and arsenic contamination on the polychaete Hediste diversicolor in different growth stages and water temperatures. Feeding activity and biochemical responses-cholinesterase activity, indicators of cell damage, antioxidant and biotransformation enzymes and metabolic capacity-were evaluated. Temperature rise combined with As imposed alterations on feeding activity and biochemical endpoints at different growth stages. Small organisms have their antioxidant enzymes increased, avoiding lipid damage. However, larger organisms are the most affected class due to the inhibition of superoxide dismutase, which results in protein damage. Oxidative damage was observed on smaller and larger organisms exposed to As and temperature of 21 °C, demonstrating higher sensibility to the combination of temperature rise and As. The observed alterations may have ecological consequences, affecting the cycle of nutrients, sediment oxygenation and the food chain that depends on the bioturbation of this polychaete.

Identification of a novel CYP4V gene in the polychaete Perinereis aibuhitensis: transcriptional comparison with a CYP4B gene exposed to PAHs

Polychaete worms can biotransform polycyclic aromatic hydrocarbons (PAHs) in environments, and the cytochrome P450 (CYP) enzyme plays an important role in this process. Herein, a novel cytochrome P450 gene was identified and characterized from the polychaete worm Perinereis aibuhitensis. The full-length cDNA, which is named CYP4V82, is 1709 bp encoding a protein of 509 amino acids and has high similarity to CYP4V. The expression levels of CYP4V82 and CYP4BB4 (a CYP gene identified from P. aibuhitensis in a previous study, Chen et al. Mar Pollut Bull 64:1782-1788, 2012) exposure to various concentrations of benzo[a]pyrene (B[a]P) (0.5, 2, 4, and 8 μg/L) and same mass concentrations of fluoranthene (Flu, 3.2 μg/L), phenanthrene (Phe, 2.9 μg/L), B[a]P (4.0 μg/L) were detected to identify the function of the CYP4 family in P. aibuhitensis. Compared with CYP4BB4, CYP4V82 mRNA was minimally expressed on day 7 but highly sensitive on day 14. Notably, the expression levels of CYP4V82 and CYP4BB4 were relatively different in short-term responses to PAHs with different benzene rings of the same concentration. The expression of CYP4V82 in the B[a]P group was the highest, while that of CYP4BB4 in the Phe group was relatively higher than the two other groups. These findings suggest that PAHs are associated with the induction of CYP4V82 and CYP4BB4 expressions in P. aibuhitensis, which may have different efficiencies in the detoxification of PAHs.

Effects of graphene oxide nanosheets in the polychaete Hediste diversicolor: Behavioural, physiological and biochemical responses

Numerous applications exist for graphene-based materials, such as graphene oxide (GO) nanosheets. Increased concentrations of GO nanosheets in the environment have the potential to have a large negative effect on the aquatic environment, with consequences for benthic organisms, such as polychaetes. The polychaete Hediste diversicolor mobilises the sediments, hence altering the availability of contaminants and the nutrients biogeochemical cycle. As such, this study proposes to assess the effects of different GO nanosheet concentrations on the behaviour, feeding activity, mucus production, regenerative capacity, antioxidant status, biochemical damage and metabolism of H. diversicolor. This study evidenced that H. diversicolor exposed to GO nanosheets had a significantly lower ability to regenerate their bodies, took longer to feed and burrow into the sediment and produced more mucus. Membrane oxidative damage (lipid peroxidation) increased in exposed specimens. The increased metabolic rate (ETS) evidenced a higher energy expenditure in exposed organisms (high use of ready energy sources - soluble sugars) to fight the toxicity induced by GO nanosheets, such as SOD activity. The increase in SOD activity was enough to reduce reactive oxygen species (ROS) induced by GO on cytosol at the lowest concentrations, avoiding the damage on proteins (lower PC levels), but not on membranes (LPO increase). This study revealed that the presence of GO nanosheets, even at the lower levels tested, impaired behavioural, physiological, and biochemical traits in polychaetes, suggesting that the increase of this engineered nanomaterial in the environment can disturb these benthic organisms, affecting the H. diversicolor population. Moreover, given the important role of this group of organisms in coastal and estuarine food webs, the biogeochemical cycle of nutrients, and sediment oxygenation, there is a real possibility for repercussions into the estuarine community.

Effects of ocean acidification on the biochemistry, physiology and parental transfer of Ampelisca brevicornis (Costa, 1853)

Ocean acidification (OA) has received more attention in the marine research community in recent years than any other topic. Excess carbon dioxide makes the ocean more acidic, threatening marine ecosystems. There has been little research on the impact of OA on crustaceans, particularly on their physiological and potential ecosystem-level consequences. Thus, we investigated the impacts of OA on the physiological and biochemical characteristics of the estuarine amphipod Ampelisca brevicornis. Ovigerous amphipods were harvested from nature and maintained in the laboratory to produce juveniles, which were then further reared to obtain the mature adults (F0) and successive offspring (F1). For this study, four pH treatments (pH 8.1, 7.5, 7.0, and 6.5) mimicking future OA were evaluated to understand the physiological and biochemical effects on the organisms. The findings of this study suggest that A. brevicornis is more vulnerable to OA than was previously established in short-term trials. The survival was significantly reduced as pH decreased over time and a significant interaction between pH and time was observed. Survival was higher in F1 than in F0 juveniles and vice versa in terms of growth. Animal's physiological responses such as growth, burrowing behavior, locomotor activity, swimming speed, ventilation rate and reproductive performance were negatively influenced by acidification. These physiological characteristics can be linked to the oxidative stress induced by global change conditions because excess of free radicals degrade cell functioning, affecting species' biochemical and physiological performance. These alterations may have long-term negative impacts, with ecological consequences. The results of this study provide baseline information regarding the effect of OA on this keystone crustacean that may be useful in simulating the impacts of OA to develop different conceptual models for a better understanding of the consequences and implications of climate change in the future for managing marine ecosystems.

Vortex-Assisted Dispersive Molecularly Imprinted Polymer-Based Solid Phase Extraction of Acetaminophen from Water Samples Prior to HPLC-DAD Determination

In the present study, acetaminophen (ACT) molecularly imprinted polymer (ACT-MIP) were successfully synthesized via surface imprinting polymerization. The structural and morphological properties of ACT-MIP were characterized using various analytical techniques. ACT-MIP were used as an adsorbent in a vortex-assisted dispersive molecularly imprinted solid-phase micro-extraction (VA-d-μ-MISPE), coupled with a high-performance liquid chromatography–diode array detector (HPLC-DAD) method for the determination of ACT in water samples. Influential parameters such as the mass of adsorbent, vortex speed, extraction time, desorption volume, and desorption time were optimized using a multivariate approach. Under optimum conditions, the maximum binding capacities of ACT-MIP and NIP (non-imprinted polymers) were 191 mg/g and 71.5 mg/g, respectively. The linearity was attained across concentrations ranging from 0.630 to 500 µg/L, with a coefficient of determination of 0.9959. For ACT-MIP, the limit of detection (LOD) and limit of quantification (LOQ), enhancement factor, and precision of the method were 0.19 ng/L, 0.63 ng/L, 79, and <5%, respectively. The method was applied in the analysis of spiked water samples, and satisfactory percentage recoveries in the range of 95.3–99.8% were obtained.

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.

Immunity and inflammatory responses in gilthead sea bream (Sparus aurata L.) exposed to sub-lethal mixture of carbamazepine, cadmium chloride and polybrominated diphenyl ether

Chemical contaminants such as industrial and urban by-products, pharmaceuticals, drugs metabolites and, plastics, are continuously found in the oceans, affecting its quality and organism's welfare. Although these compounds are found at concentrations ranged ng L^-1, there is an increasing concern about the potential adverse effects of the interactions among those substances present, simultaneously, in a mixture. In the present study, specimens of sea bream (Sparus aurata) were exposed, by food, to rising concentrations of a mixture of carbamazepine, polybrominated diphenyl ether-47 and cadmium chloride, for 15 days and then, maintained, with the same control diet, without contaminants, for other 15 days. Samples of skin mucus, serum, head-kidney, liver and intestine were sampled at 0, 15 and 30 days. Cellular immune parameters were evaluated on head-kidney, as well as humoral parameters were determined on skin mucus and serum. In addition, the expression of some genes, related to immunity, was analysed on liver and intestine. Both cellular and humoral response were affected at 15 days, showing slightly signs of recovery at 30 days. Besides, the expression of immune-related genes was highly affected, suggesting the development of inflammatory processes, as well as a reduction of immune parameters. Overall, the mixture of compounds severally affected the immune system of sea bream, suggesting a lower degree of recovery. The prolonged exposure to a mixture of these compounds could entail serious change on population immunity and, eventually, promote changes on marine biota.

Experimental evidence of uncertain future of the keystone ragworm Hediste diversicolor (O.F. Müller, 1776) under climate change conditions

It is currently assumed that climate change related factors pose severe challenges to biodiversity maintenance. This paper assesses the multi-stressor effects of elevated temperature (15 °C as control, 25 °C as elevated) and CO₂ levels (pH 8.1 as control, 7.5 and 7.0 representing acidifying conditions) on the physiological (survival and regenerative capacity), behavioral (feeding and burrowing activities), and biochemical changes (metabolic capacity, oxidative status and biotransformation mechanisms) experienced by the keystone polychaete Hediste diversicolor. Temperature rise enlarged the adverse effect of marine acidification on the survival of H. diversicolor, delayed the beginning of the excavation activity, enhancing the negative effects that pH decrease had in the burrowing behavior of this polychaete. Additionally, regardless of the temperature, exposure of H. diversicolor to acidification results in a reduction in the feeding rate. It is the first time that this decreased feeding capacity is found related to seawater acidification in this species. The healing of the wound and the blastemal formation were retarded due to these two climatic factors which hinder the regenerative process of polychaetes. These vital physiological functions of H. diversicolor can be related to the oxidative stress induced by climate change conditions since free radicals overproduced will impair cells functioning, affecting species biochemical and physiological performance, including feeding and tissue regeneration. The present results also demonstrated that although polychaetes' metabolic capacity was enhanced under stress conditions, organisms were still able to increase or maintain their energy reserves. Our findings are of major environmental relevance considering that predicted climate change conditions will affect species vital and ecological and physiological capacities. These can be translated into shrinking not only at the individual and population level but also in microbial and endofaunal diversities, in the detritus processing in estuaries and biogeochemical cycles at the ecosystem level. Thus the conservation of H. diversicolor populations is vital for the normal functioning of estuarine mudflat ecosystems.

The use of Hediste diversicolor in the study of emerging contaminants

The contamination of aquatic environments has been the focus of research to understand effects on ecosystems and its species. Benthic organisms are considered potential targets since sediments act as sources and sinks for environmental contaminants. This review presents information on the effects of three types of emerging contaminants: pharmaceuticals (tested concentrations between 0.1 ng/L - 250 mg/L and 0.01 ng/g - 2.5 μg/g), metal-based nanoparticles (<100 nm) (tested concentrations between 10 μg/L - 1 mg/L and 5 - 140 μg/g) and micro(nano)plastics (tested concentrations between 5 μg/L - 50 mg/L and 10 - 50 mg/kg), on the polychaete Hediste diversicolor, a key species in estuarine/coastal ecosystems. Data shows that these contaminants promote alterations in burrowing activity (lowest concentration inducing effects: 10 ng/L), neurotransmission and damage related parameters (lowest concentration inducing effects: 100 ng/L). The characteristics of this polychaete, such as regenerative capacity, make the use of this species in biomedical studies involving environmental contaminants valuable.

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

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

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.

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.

Effects of mixtures of anticancer drugs in the benthic polychaete Nereis diversicolor

The increasing consumption of anticancer drugs through single and/or combinatory chemotherapy worldwide raised concern regarding their toxicity burden in coastal zones. The toxicity of a mixture of three compounds involving the drugs cisplatin (CisPt), cyclophosphamide (CP) and tamoxifen (TAM) was determined on the marine polychaete Nereis diversicolor exposed to an increasing range of their concentrations, respectively: Mix A: 0.1 + 10 + 0.1 ng L^-1; Mix B: 10 + 100 + 10 ng L^-1; Mix C: 100 + 500 + 25 ng L^-1; Mix D: 100 + 1000 + 100 ng L^-1. Different endpoints were assessed, including disturbance in the burrowing behaviour, neurotoxicity (acetylcholinesterase - AChE activity), antioxidant enzymes (superoxide dismutase - SOD; catalase - CAT; selenium-dependent glutathione peroxidase - Se-GPx and total glutathione peroxidases T-GPx activities), biotransformation metabolism (glutathione-S-transferases - GST), lipid peroxidation (LPO) and genotoxicity (DNA damage). Biological effects of the mixtures of anticancer compounds on N. diversicolor were compared with previous studies about effects on the same biological model under single-drug exposure conducted with the same molecules. Regarding SOD activity, TAM showed an antagonist effect over CisPt and CP in mixtures C and D. In Mix D, there was a synergistic effect of TAM and CisPt that inhibited CAT activity and an additive interaction of CisPt and CP on the Phase II biotransformation enzyme. Drugs in Mix A also suppressed polychaetes' GST activity, although different from the respective single-drug responses, besides able to induce T-GPx activity, that was not sufficient to avoid oxidative damage and mid-grade DNA damage. Due to the absence of burrowing impairment in Mix A, mechanisms involved in neurotoxicity were other than the one driven by AChE alterations. At the intermediary concentrations (Mix B and C), only LPO occurred. Data from drugs individually may not predict the risks provided by mixtures.

An Anticaffeine Antibody-Oligonucleotide Conjugate for DNA-Directed Immobilization in Environmental Immunoarrays

The development of fast and cheap high-throughput platforms for the detection of environmental contaminants is of particular importance to understand the human-related impact on the environment. The application of DNA-directed immobilization (DDI) of IgG molecules is currently limited to the clinical diagnostics scenario, possibly because of the high costs of production of such addressable platforms. We here describe the efficient and specific hybridization of an antibody-oligonucleotide conjugate to a short 12-mer capture probe. The specific antibody used is a monoclonal antibody against caffeine, a stimulant and important anthropogenic marker. With this work, we hope to contribute to broadening the application potential of DDI to environmental markers in order to develop cheaper and more stable high-throughput screening platforms for standard routine analysis of pollutants in a variety of complex matrices.

The influence of salinity on the effects of Multi-walled carbon nanotubes on polychaetes

Salinity shifts in estuarine and coastal areas are becoming a topic of concern and are one of the main factors influencing nanoparticles behaviour in the environment. For this reason, the impacts of multi-walled carbon nanotubes (MWCNTs) under different seawater salinity conditions were evaluated on the common ragworm Hediste diversicolor, a polychaete species widely used as bioindicator of estuarine environmental quality. An innovative method to assess the presence of MWCNT aggregates in the sediments was used for the first time. Biomarkers approach was used to evaluate the metabolic capacity, oxidative status and neurotoxicity of polychaetes after long-term exposure. The results revealed an alteration of energy-related responses in contaminated polychaetes under both salinity conditions, resulting in an increase of metabolism and expenditure of their energy reserves (lower glycogen and protein contents). Moreover, a concentration-dependent toxicity (higher lipid peroxidation, lower ratio between reduced and oxidized glutathione and activation of antioxidant defences and biotransformation mechanisms) was observed in H. diversicolor, especially when exposed to low salinity. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to MWCNTs at both salinities.

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.

Physiological and biochemical impacts induced by mercury pollution and seawater acidification in Hediste diversicolor

The present study evaluated the impacts of predicted seawater acidification and Hg pollution, when stressors were acting alone and in combination, on the polychaete Hediste diversicolor. Polychaetes were exposed during 28days to low pH (7.5), Hg (5μg/L) and pH7.5+Hg, and physiological alterations (respiration rate), biochemical markers related to metabolic potential (glycogen and protein content, electron transport system activity) and oxidative status (activity of antioxidant and biotransformation enzymes, lipid peroxidation) were evaluated. The results obtained clearly showed that polychaetes were sensitive to low pH and Hg contamination, both acting alone or in combination. Organisms used their energy reserves under stressful conditions, which decreased by up to half of the control content, probably to fuel defence mechanisms. Our findings further demonstrated that polychaetes exposed to these stressors presented increased antioxidant defence mechanisms (3 fold compared to control). However, organisms were not able to prevent cellular damage, especially noticed at Hg exposure and pH7.5. Overall, although all the tested conditions induced oxidative stress in Hediste diversicolor, the combined effect of seawater acidification and Hg contamination did not induce higher impacts in polychaetes than single stressor exposures. These findings may indicate that predicted climate change scenarios may not increase Hediste diversicolor sensitivity towards Hg and may not significantly change the toxicity of this contaminant to this polychaete species.