The Biological Effects of Pharmaceuticals in the Marine Environment

Exposure to environmental pharmaceuticals affects the macromolecular composition of mussels digestive glands

Human pharmaceuticals represent a major challenge in natural environment. A better knowledge on their mechanisms of action and adverse effects on cellular pathways is fundamental to predict long-term consequences for marine wildlife. The FTIRI Imaging (FTIRI) spectroscopy represents a vibrational technique allowing to map specific areas of non-homogeneous biological samples, providing a unique biochemical and ultrastructural fingerprint of the tissue. In this study, FTIRI technique has been applied, for the first time, to characterize (i) the chemical building blocks of digestive glands of Mytilus galloprovincialis, (ii) alterations and (iii) resilience of macromolecular composition, after a 14-days exposure to 0.5 µg/L of carbamazepine (CBZ), valsartan (VAL) and their mixture, followed by a 14-days recovery period. Spectral features of mussels digestive glands provided insights on composition and topographical distribution of main groups of biological macromolecules, such as proteins, lipids, and glycosylated compounds. Pharmaceuticals caused an increase in the total amount of protein and a significant decrease of lipids levels. Changes in macromolecular features reflected the modulation of specific molecular and biochemical pathways thus supporting our knowledge on mechanisms of action of such emerging pollutants. Overall, the applied approach could represent an added value within integrated strategies for the effects-based evaluation of environmental contaminants.

Occurrence of phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) in key species of anthozoans in Mediterranean Sea

The Mediterranean Sea's biodiversity is declining due to climate change and human activities, with plastics and emerging contaminants (ECs) posing significant threats. This study assessed phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) occurrence in four anthozoan species (Cladocora caespitosa, Eunicella cavolini, Madracis pharensis, Parazoanthus axinellae) using solid phase microextraction (SPME) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All specimens were contaminated with at least one contaminant, reaching maximum values of 57.3 ng/g for the ∑PAEs and 64.2 ng/g (wet weight) for ∑APIs, with dibutyl phthalate and Ketoprofen being the most abundant. P. axinellae was the most contaminated species, indicating higher susceptibility to bioaccumulation, while the other three species showed two-fold lower concentrations. Moreover, the potential adverse effects of these contaminants on anthozoans have been discussed. Investigating the impact of PAEs and APIs on these species is crucial, given their key role in the Mediterranean benthic communities.

Transcriptomic profiles of brains in juvenile Atlantic cod (Gadus morhua) exposed to pharmaceuticals and personal care products from a wastewater treatment plant discharge

Pharmaceuticals and personal care products (PPCPs) are frequently detected in marine environments, posing a threat to aquatic organisms. Our previous research demonstrated the occurrence of neuroactive compounds in effluent and sediments from a wastewater treatment plant (WWTP) in a fjord North of Stavanger, the fourth-largest city in Norway. To better understand the influence of PPCP mixtures on fish, Atlantic cod (Gadus morhua) were caged for one month in 3 locations: site 1 (reference), site 2 (WWTP discharge), and site 3 (6.7 km west of discharge). Transcriptomic profiling was conducted in the brains of exposed fish and detection of PPCPs in WWTP effluent and muscle fillets were determined. Caffeine (47.8 ng/L), benzotriazole (10.9 ng/L), N,N-diethyl-meta-toluamide (DEET) (5.6 ng/L), methyl-1H-benzotriazole (5.5 ng/L), trimethoprim (3.4 ng/L), carbamazepine (2.1 ng/L), and nortriptyline (0.4 ng/L) were detected in the WWTP effluent. Octocrylene concentrations were observed in muscle tissue at all sites and ranged from 53 to 193 ng/g. Nervous system function and endocrine system disorders were the top enriched disease and function pathways predicted in male and female fish at site 2, with the top shared canonical pathways involved with estrogen receptor and Sirtuin signaling. At the discharge site, predicted disease and functional responses in female brains were involved in cellular assembly, organization, and function, tissue development, and nervous system development, whereas male brains were involved in connective tissue development, function, and disorders, nervous system development and function, and neurological disease. The top shared canonical pathways in females and males were involved in fatty acid activation and tight junction signaling. This study suggests that pseudopersistent, chronic exposure of native juvenile Atlantic cod from this ecosystem to PPCPs may alter neuroendocrine and neuron development.

Bioaccumulation of pharmaceuticals and stimulants in macrobenthic food web in the European Arctic as determined using stable isotope approach

Although pharmaceuticals are increasingly detected in abiotic matrices in the Arctic, the accumulation of drugs in the resident biota and trophic transfer have not been yet examined. This study investigated the behaviour of several pharmaceuticals in the rocky-bottom, macrobenthic food web in the coastal zone of Isfjorden (western Spitsbergen) using stable isotope analyses (SIA) coupled with liquid chromatography-mass spectrometry (LC-MS/MS). Across 16 macroalgal and invertebrate species the highest average concentration was measured for ciprofloxacin (CIP) (on average 60.3 ng g-1 dw) followed by paracetamol (PCT) (51.3 ng g-1 dw) and nicotine (NIC) (37.8 ng g-1 dw). The biomagnification potential was assessed for six target compounds of 13 analytes detected that were quantified with a frequency > 50 % in biological samples. The trophic magnification factor (TMF) ranged between 0.3 and 2.8, and was significant for NIC and CIP. TMF < 1.0 for NIC (0.3; confidence interval, CI 0.1-0.5) indicated that the compound does not accumulate with trophic position. The dilution of pharmaceutical residues in the food web may result from limited intake with dietary route, poor assimilation efficiency and high biotransformation rates in benthic invertebrates. TMF for CIP (2.8, CI 1.2-6.4) suggests trophic magnification, a phenomenon observed previously for several antibiotics in freshwater food webs. Trophic transfer therefore plays a role in controlling concentration of CIP in the Arctic benthic communities and should be considered in environmental risk assessment. Biomagnification potential of diclofenac (DIC; 0.9, CI 0.5-1.7), carbamazepine (CBZ; 0.4, CI 0.1-2.1), caffeine (CAF; 0.9, CI 0.5-1.9) and PCT (1.3, CI 0.7-2.7) was not evident due to large 95 % confidence of their TMFs. This study provides the first evidence of drug bioaccumulation in the Arctic food web and indicates that behaviour of pharmaceuticals varies among target compounds.

Ecotoxicology Evaluation of a Fenton-Type Process Catalyzed with Lamellar Structures Impregnated with Fe or Cu for the Removal of Amoxicillin and Glyphosate

Antibiotics and pesticides, as well as various emerging contaminants that are present in surface waters, raise significant environmental concerns. Advanced oxidation processes, which are employed to eliminate these substances, have demonstrated remarkable effectiveness. However, during the degradation process, by-products that are not completely mineralized are generated, posing a substantial risk to aquatic ecosystem organisms; therefore, it is crucial to assess effluent ecotoxicity following treatment. This study aimed to assess the toxicity of effluents produced during the removal of amoxicillin and glyphosate with a Fenton-type process using a laminar structure catalyzed with iron (Fe) and copper (Cu). The evaluation included the use of Daphnia magna, Selenastrum capricornutum, and Lactuca sativa, and mutagenicity testing was performed using strains TA98 and TA100 of Salmonella typhimurium. Both treated and untreated effluents exhibited inhibitory effects on root growth in L. sativa, even at low concentrations ranging from 1% to 10% v/v. Similarly, negative impacts on the growth of algal cells of S. capricornutum were observed at concentrations as low as 0.025% v/v, particularly in cases involving amoxicillin-copper (Cu) and glyphosate with copper (Cu) and iron (Fe). Notably, in the case of D. magna, mortality was noticeable even at concentrations of 10% v/v. Additionally, the treatment of amoxicillin with double-layer hydroxides of Fe and Cu resulted in mutagenicity (IM ≥ 2.0), highlighting the necessity to treat the effluent further from the advanced oxidation process to reduce ecological risks.

Fish as models to study liver and blood lipid-related effects of fibrates and statins and screen new hypolipidemic drugs

Fibrates and statins lead worldwide prescriptions of lipid-lowering drugs, whose consumption is increasing considerably due to the growing incidence of dyslipidemias, particularly in high-income areas. Consequently, these chemicals are frequently found in aquatic environments, usually closer to highly urbanized and populated areas, reaching the water systems primarily through waste-water treatment plant (WWTP) effluents. Despite that, the knowledge regarding the effects caused by fibrates and statins in fish, namely in liver lipid metabolism and blood-related parameters, is still very limited. There is yet no standardized fish model for testing the effects of those drugs. However, experimental evidence suggests that the mechanisms of action (MoA) of fibrates and statins are fairly similar to those observed in humans, which makes these aquatic organisms viable alternatives for toxicological and mechanistic studies. This graphical review serves as a state point regarding the potential use of fish as a model for the study of hypolipidemic compounds, addressing (I) the current state of aquatic pollution caused by statins and fibrates, (II) the experimental designs used in the literature to assess effects on fish, (III) the liver metabolism and blood effects caused by exposure to fibrates and statins, as well as (IV) the MoA of both drugs. It further focuses on the current and future benefits of establishing a standardized fish model(s) for testing hypolipidemic drugs.

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

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

Microplastics in coastal and oceanic surface waters and their role as carriers of pollutants of emerging concern in marine organisms

Microplastics (Mps) pose a significant environmental challenge with global implications. To examine the effect of Mps on coastal and oceanic surface waters, as well as in marine organisms, 167 original research papers published between January 2013 and September 2022 were analyzed. The study revealed an unequal distribution of research efforts across the world. Fragments and fibers were the most frequently detected particles in ocean surface waters and marine biota, which mainly consisted of colored and transparent microparticles. Sampling of Mps was primarily done using collecting nets with a mesh size of 330 μm. Most articles used a stereomicroscope and Fourier-Transform Infrared spectroscopy for identification and composition determination, respectively. Polyethylene and polypropylene were the most frequent polymers found, both in coastal waters and in marine organisms. The major impact observed on marine organisms was a reduction in growth rate, an increase in mortality, and reduced food consumption. The hydrophobic nature of plastics encourages the formation of biofilms called the "plastisphere," which can carry pollutants that are often toxic and can enter the food chain. To better define management measures, it is necessary to standardize investigations that assess Mp pollution, considering not only the geomorphological and oceanographic features of each region but also the urban and industrial occupation of the studied marine environments.

Titanium (IV) oxide anatase nanoparticles as vectors for diclofenac: assessing the antioxidative responses to single and combined exposures in the aquatic macrophyte Egeria densa

Titanium dioxide, frequently used in commonplace products, is now regularly detected in aquatic environments. Understanding its toxic effects on native biota is essential. However, combined toxicity with commonly occurring pollutants, such as the pharmaceutical diclofenac, may provide more insight into environmental situations. Therefore, the present study aimed to evaluate the effects of titanium dioxide and diclofenac, individually and combined, on the macrophyte Egeria densa. Diclofenac uptake and removal by the macrophyte were assessed. Diclofenac and titanium dioxide were mixed prior to exposure to allow binding, which was assessed. Toxicity of the individual compounds and the combination was evaluated by assaying enzymes as bioindicators of biotransformation and the antioxidative system. Cytosolic glutathione S-transferase and glutathione reductase activities were increased by diclofenac, titanium dioxide, and the combination. Both enzymes' activities were more significantly elevated by diclofenac and the combination than nanoparticles alone. Microsomal glutathione S-transferase was unaffected by diclofenac exposure but inhibited with titanium dioxide and the mixture. Diclofenac elicited the most significant response. Based on the data, the cytosolic enzymes effectively prevented damage.

Immobilization, oxidative stress and antioxidant response of Daphnia magna to Amoxicillin and Ciprofloxacin

Amoxicillin (AMX) and ciprofloxacin (CPX) are broad-spectrum antibiotics with wide application in agriculture and human and veterinary medicine. The drugs end up in the environment where their impact on zooplankton remains scantily understood. This study investigated the immobilization, risk assessment (RQ), antioxidant response, and biochemical changes of Daphnia magna post-exposure to AMX and CPX. Sixty-percent immobilization of Daphnia occurred at 200 μg L^-1 AMX and CPX, while EC₅₀ values were 2391.6 μg L^-1 and 273.4 μg L^-1, respectively. RQs were 113.3 and 11,481.5, while Toxic units were 41.6 and 364.9 for AMX and CPX, respectively. Both antibiotics caused a significant rise in intracellular hydrogen peroxide 48 h post-exposure, indicating oxidative stress. Lipid peroxidation and antioxidant enzyme activity were considerably altered during the research. Thus, environmentally relevant concentrations of AMX and CPX pose an adverse risk that could change the population dynamics of Daphnia magna.

Mixtures of environmental pharmaceuticals in marine organisms: Mechanistic evidence of carbamazepine and valsartan effects on Mytilus galloprovincialis

Unravelling the adverse outcomes of pharmaceuticals mixture represents a research priority to characterize the risk for marine ecosystems. The present study investigated, for the first time, the interactions between two of the most largely detected pharmaceuticals in marine species: carbamazepine (CBZ) and valsartan (VAL), elucidating mechanisms that can modulate bioaccumulation, excretion and the onset of toxicity. Mytilus galloprovincialis were exposed to environmental levels of CBZ and VAL dosed alone or in combination: measurement of drug bioaccumulation was integrated with changes in the whole transcriptome and responsiveness of various biochemical and cellular biomarkers. Interactive and competing mechanisms between tested drugs were revealed by the much higher CBZ accumulation in mussels exposed to this compound alone, while an opposite trend was observed for VAL. A complex network of responses was observed as variations of gene expression, functional effects on neurotransmission, cell cycle, immune responses and redox homeostasis. The elaboration of results through a quantitative Weight of Evidence model summarized a greater biological reactivity of CBZ compared to VAL and antagonistic interactions between these compounds, resulting in a reduced effect of the antiepileptic when combined with valsartan. Overall, new perspectives are highlighted for a more comprehensive risk assessment of environmental mixtures of pharmaceuticals.

Untargeted Metabolomics Reveals Antidepressant Effects in a Marine Photosynthetic Organism: The Diatom Phaeodactylum tricornutum as a Case Study

The increased use of antidepressants, along with their increased occurrence in aquatic environments, is of concern for marine organisms. Although these pharmaceutical compounds have been shown to negatively affect marine diatoms, their mode of action in these non-target, single-cell phototrophic organisms is yet unknown. Using a Fourier-transform ion cyclotron-resonance mass spectrometer (FT-ICR-MS) we evaluated the effects of fluoxetine in the metabolomics of the model diatom Phaeodactylum tricornutum, as well as the potential use of the identified metabolites as exposure biomarkers. Diatom growth was severely impaired after fluoxetine exposure, particularly in the highest dose tested, along with a down-regulation of photosynthetic and carbohydrate metabolisms. Notably, several mechanisms that are normally down-regulated by fluoxetine in mammal organisms were also down-regulated in diatoms (e.g., glycerolipid metabolism, phosphatidylinositol signalling pathway, vitamin metabolism, terpenoid backbone biosynthesis and serotonin remobilization metabolism). Additionally, the present work also identified a set of potential biomarkers of fluoxetine exposure that were up-regulated with increasing fluoxetine exposure concentration and are of high metabolic significance following the disclosed mode of action, reinforcing the use of metabolomics approaches in ecotoxicology.

Marine heatwaves hamper neuro-immune and oxidative tolerance toward carbamazepine in Mytilus galloprovincialis

The increased frequency and intensity of short-term extreme warming phenomena have been associated to harsh biological and ecosystem outcomes (i.e., mass mortalities in marine organisms). Marine heatwaves (MHWs), occurring when seasonal temperature threshold is exceeded for at least 5 consecutive days, may reduce the tolerance of coastal species toward additional pressures, but interactions between such multiple stressors are virtually unexplored. The present study aimed to characterize in Mytilus galloprovincialis the influence of a simulated MHW scenario on the toxicological effects of the pharmaceutical carbamazepine (CBZ), ubiquitously detected in the marine environment and chosen as model compound for this relevant class of emerging contaminants. The bioaccumulation of CBZ and responsiveness of various biological parameters, including immune system, antioxidant status, lipid metabolism and cellular integrity, were analyzed in exposed mussels both during and after the end of the heatwave. MHW appeared to strongly modulate accumulation of CBZ, paralleled by weakened immunocompetence and onset of oxidative disturbance that finally evolved to cellular damages and lipid metabolism disorders. Elaboration of the overall results through a quantitative Weight of Evidence model, revealed the highest hazard in organisms exposed to both the stressors 10 days after the end of the heatwave, suggesting that MHWs could leave a footprint on the capability of mussels to counteract CBZ toxicity, thus affecting their vulnerability and predisposition to adverse effects toward multiple stressors.