Water temperature affects the biotransformation and accumulation of a psychoactive pharmaceutical and its metabolite in aquatic organisms

Assessment, distribution, and ecological risk of contaminants of emerging concern in a surface water-sediment-fish system impacted by wastewater

The presence of contaminants of emerging concern in aquatic ecosystems represents an ever-increasing environmental problem. Aquatic biota is exposed to these contaminants, which can be absorbed and distributed to their organs. This study focused on the assessment, distribution, and ecological risk of 32 CECs in a Spanish river impacted by effluents from a wastewater treatment plant, analyzing the organs and plasma of common carp. Environmental concentrations in water and sediment were examined at sites upstream and downstream of the wastewater treatment plant. The two downstream sites showed 15 times higher total concentrations (12.4 μg L-1 and 30.1 μg L-1) than the two upstream sites (2.08 μg L-1 and 1.66 μg L-1). Half of the CECs were detected in fish organs, with amantadine having the highest concentrations in the kidney (158 ng g-1 w.w.) and liver (93 ng g-1 w.w.), followed by terbutryn, diazepam, and bisphenol F in the brain (50.2, 3.82 and 1.18 ng g-1 w.w.). The experimental bioaccumulation factors per organ were compared with the bioconcentration factors predicted by a physiologically based pharmacokinetic model, obtaining differences of one to two logarithmic units for most compounds. Risk quotients indicated a low risk for 38 % of the contaminants. However, caffeine and terbutryn showed an elevated risk for fish. The mixed risk quotient revealed a medium risk for most of the samples in the three environmental compartments: surface water, sediment, and fish.

Predicted concentrations of antineoplastic drugs in the aquatic environment: The case of Ría de Vigo (NW, Spain)

The European Medicines Agency (EMA) mandates Environmental Risk Assessments (ERAs) since 2006 to determine potential risks of new marketed medicines. Drugs with a Predicted Environmental Concentration (PEC) in inland surface waters exceeding 0.01 μg L-1 require further environmental risk assessment. PEC may be refined based on prevalence data and/or based on the treatment regimen. In this study, based on EMA regulations, refined PEC of 108 antineoplastic drugs in coastal waters were determined based on the consumption in a coastal health area during 2021, identifying six drugs with potential environmental risk in surface waters (hydroxyurea, capecitabine, abiraterone, ibrutinib, imatinib and 5-fluorouracil) and two in marine ecosystem (hydroxyurea and capecitabine). Comparison of these refined PECs with data from marketing laboratories revealed significant disparities, suggesting the need for regular updates, especially with changes in drug indications or financing. Notably, the identified drugs are not yet on the main reference lists of emerging contaminants.

Uptake/depuration kinetics, bioaccumulation potential and metabolic transformation of a complex pharmaceutical mixture in zebrafish (Danio rerio)

Uptake and elimination kinetics, bioconcentration factors (BCFs), and metabolic transformation of 20 different pharmaceutically active compounds (PhACs), covering a wide range of therapeutic categories and physico-chemical properties, were studied using zebrafish (Danio rerio). The fish were exposed to the mixture of the selected PhACs at environmentally relevant concentrations similar to 10 µg L-1. The experiments were performed in semi-static conditions and comprised a 7-day uptake period followed by a 7-day depuration period. Most of the PhACs reached a concentration plateau within the 7-day uptake-phase which was followed by an efficient depuration, with the observed uptake (ku) and depuration rate constants (kd,) ranging between 0.002 and 3.752 L kg-1 h-1, and 0.010 to 0.217 h-1, respectively. The investigated PhACs showed low to moderate BCFs. The highest BCFs of 47.8, 28.6 and 47.6 L kg-1 were determined for sertraline, diazepam and desloratadine, respectively. A high contribution of metabolic products to the total internal concentration was observed for some PhACs such as codeine (69%), sulfamethoxazole (51%) and verapamil (87%), which has to be taken into account when assessing the bioconcentration potential. Moreover, most of the metabolites exhibited significantly longer half-lives in zebrafish than their parent compounds and affected the overall depuration kinetics.

Organ-specific biotransformation in salmonids: Insight into intrinsic enzyme activity and biotransformation of three micropollutants

Aquatic ecosystems continue to be threatened by chemical pollution. To what extent organisms are able to cope with chemical exposure depends on their ability to display mechanisms of defense across different organs. Among these mechanisms, biotransformation processes represent key physiological responses that facilitate detoxification and reduce the bioaccumulation potential of chemicals. Biotransformation does not only depend on the ability of different organs to display biotransformation enzymes but also on the affinity of chemicals towards these enzymes. In the present study, we explored the ability of different organs and of two freshwater fish to support biotransformation processes through the determination of in vitro phase I and II biotransformation enzyme activity, and their role in supporting intrinsic clearance and the formation of biotransformation products. Three environmentally relevant pollutants were evaluated: the polycyclic aromatic hydrocarbon (PAH) pyrene (as recommended by the OECD 319b test guideline), the fungicide azoxystrobin, and the pharmaceutical propranolol. Comparative studies using S9 sub-cellular fractions derived from the liver, intestine, gills, and brain of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) revealed significant phase I and II enzyme activity in all organs. However, organ- and species-specific differences were found. In brown trout, significant extrahepatic biotransformation was observed for pyrene but not for azoxystrobin and propranolol. In rainbow trout, the brain appeared to biotransform azoxystrobin. In this same species, propranolol appeared to be biotransformed by the intestine and gills. Biotransformation products could be detected only from hepatic biotransformation, and their profiles and formation rates displayed species-specific patterns and occurred at different magnitudes. Altogether, our findings further contribute to the current understanding of organ-specific biotransformation capacity, beyond the expression and activity of enzymes, and its dependence on specific enzyme-chemical interactions to support mechanisms of defense against exposure.

The effect of warming and seasonality on bioaccumulation of selected pharmaceuticals in freshwater invertebrates

Multiple human-induced environmental stressors significantly threaten global biodiversity and ecosystem functioning. Climate warming and chemical pollution are two widespread stressors whose impact on freshwaters is likely to increase. However, little is known about the combined effects of warming on the bioaccumulation of environmentally relevant mixtures of emerging contaminants, such as pharmaceutically active compounds (PhACs) in freshwater biota. This study investigated the bioaccumulation of a mixture of 15 selected PhACs at environmentally relevant concentrations in common freshwater macroinvertebrate taxa, exposed to ambient temperatures and warming (+4 °C) during the warm and cold seasons in two outdoor mesocosm experiments. Nine PhACs (carbamazepine, cetirizine, clarithromycin, clindamycin, fexofenadine, telmisartan, trimethoprim, valsartan and venlafaxine) were dissipated faster in the warm season experiment than in the cold season experiment, while lamotrigine showed the opposite trend. The most bioaccumulated PhACs in macroinvertebrates were tramadol, carbamazepine, telmisartan, venlafaxine, citalopram and cetirizine. The bioaccumulation was taxon, season and temperature dependent, but differences could not be fully explained by the different water stability of the PhACs and their partitioning between water and leaf litter. The highest water-based bioaccumulation factors were found in Asellus and Planorbarius. Moreover, the bioaccumulation of some PhACs increased with warming in Planorbarius, suggesting that it could be used as a sentinel taxon in environmental studies of the effects of climate warming on PhAC bioaccumulation.

Divergent perspectives on the synergistic impacts of thermal-chemical stress on aquatic biota within the framework of climate change scenarios

Climate change, including global warming, leads to rising temperatures in aquatic ecosystems, which is one of the numerous repercussions it brings. Furthermore, water warming can indirectly impact aquatic organisms by modifying the toxicity levels of pollutants. Nevertheless, numerous studies have explored the potential impacts of chemical stress on aquatic biota, but little is known about how such chemicals and toxins interact with climate change factors, especially elevated temperatures. As such, this review paper focuses on exploring the potential effects of thermochemical stress on a wide sector of aquatic organisms, including aquatic vertebrates and invertebrates, in various aquatic ecosystems (freshwater and marine systems). Herein, the objective of this study is to explore the most up-to-date the impact of water warming (without chemical stress) and thermochemical stress on various biochemical and physiological processes in aquatic fauna and how this greatly affects biodiversity and sustainability. Therefore, there is a growing need to understand and evaluate this synergistic mechanism and its potential hazardous impacts. However, we need further investigations and scientific reports to address this serious environmental issue in order to confront anthropogenic pollutants regarding climate change and chemical pollution risks in the near future and subsequently find sustainable solutions for them.

Seasonal profile of common pharmaceuticals in edible bivalve molluscs

Pharmaceuticals are recognised as environmental contaminants of emerging concern (CECs) due to their increasing presence in the aquatic environment, along with high bioactivity linked to their therapeutic use. Therefore, information on environmental levels is urgently required. This study examined the presence of a range of common pharmaceuticals in oysters and mussels intended for human consumption from England and Wales using stable isotope dilution tandem mass spectrometry. A range of compounds were detected in bivalve tissue, with the Selective Serotonin Reuptake Inhibitor antidepressant sertraline being most abundant, reaching a maximum concentration of 22.1 ng/g wet weight shellfish tissue. Levels of all pharmaceuticals showed seasonal and geographical patterns. A dietary risk assessment revealed that the levels of pharmaceuticals identified in bivalve molluscs represent a clear hazard, but not a risk for the consumer. This study highlights the requirement for further monitoring of the presence of pharmaceuticals and other CECs in bivalve molluscs.

Understanding pharmaceutical exposure and the potential for effects in marine biota: A survey of bonefish (Albula vulpes) across the Caribbean Basin

Most research on pharmaceutical presence in the environment to date has focused on smaller scale assessments of freshwater and riverine systems, relying mainly on assays of water samples, while studies in marine ecosystems and of exposed biota are sparse. This study investigated the pharmaceutical burden in bonefish (Albula vulpes), an important recreational and artisanal fishery, to quantify pharmaceutical exposure throughout the Caribbean Basin. We sampled 74 bonefish from five regions, and analyzed them for 102 pharmaceuticals. We assessed the influence of sampling region on the number of pharmaceuticals, pharmaceutical assemblage, and risk of pharmacological effects. To evaluate the risk of pharmacological effects at the scale of the individual, we proposed a metric based on the human therapeutic plasma concentration (HTPC), comparing measured concentrations to a threshold of 1/3 the HTPC for each pharmaceutical. Every bonefish had at least one pharmaceutical, with an average of 4.9 and a maximum of 16 pharmaceuticals in one individual. At least one pharmaceutical was detected in exceedance of the 1/3 HTPC threshold in 39% of bonefish, with an average of 0.6 and a maximum of 11 pharmaceuticals exceeding in a Key West individual. The number of pharmaceuticals (49 detected in total) differed across regions, but the risk of pharmacological effects did not (23 pharmaceuticals exceeded the 1/3 HTPC threshold). The most common pharmaceuticals were venlafaxine (43 bonefish), atenolol (36), naloxone (27), codeine (27), and trimethoprim (24). Findings suggest that pharmaceutical detections and concentration may be independent, emphasizing the need to monitor risk to biota regardless of exposure diversity, and to focus on risk quantified at the individual level. This study supports the widespread presence of pharmaceuticals in marine systems and shows the utility of applying the HTPC to assess the potential for pharmacological effects, and thus quantify impact of exposure at large spatial scales.

Nabumetone and flufenamic acid pose a serious risk to aquatic plants: A study with Chlamydomonas reinhardtii as a model organism

The aquatic environment is constantly under threat due to the release of numerous pollutants. Among them, pharmaceuticals constitute a huge and diverse group. Non-steroidal anti-inflammatory drugs (NSAIDs) are increasingly found in water bodies, but knowledge about their potential toxicity is still low. In particular, there is a lack of information about their influences on aquatic plants and algae. We estimated the susceptibility of the microalgae Chlamydomonas reinhardtii to nabumetone (NBT) and flufenamic acid (FFA), focusing on photosynthesis. Due to the differences in the structures of these compounds, it was assumed that these drugs would have different toxicities to the tested green algae. The hypothesis was confirmed by determining the effective concentration values, the intensity of photosynthesis, the intensity of dark respiration, the contents of photosynthetic pigments, the fluorescence of chlorophyll a in vivo (OJIP test), and cell ultrastructure analysis. Assessment of the toxicity of the NSAIDs was extended by the calculation of an integrated biomarker response index (IBR), which is a valuable tool in ecotoxicological studies. The obtained results indicate an over six times higher toxicity of NBT compared to FFA. After analysis of the chlorophyll a fluorescence in vivo, it was found that NBT inhibited electron transport beyond the PS II. FFA, unlike NBT, lowered the intensity of photosynthesis, probably transforming some reaction centers into "silent centers", which dissipate energy as heat. The IBR estimated based on photosynthetic parameters suggests that the toxic effect of FFA results mainly from photosynthesis disruption, whereas NBT significantly affects other cellular processes. No significant alteration in the ultrastructure of treated cells could be seen, except for changes in starch grain number and autophagic vacuoles that appeared in FFA-treated cells. To the best of our knowledge, this is the first work reporting the toxic effects of NBT and FFA on unicellular green algae.

Flunitrazepam induces neurotoxicity in zebrafish through microbiota-gut-brain axis

The abuse of psychoactive substances has led to their frequent detection in the environment, with unknown effects on the nervous system. In this study, zebrafish were exposed to benzodiazepine drug flunitrazepam (FLZ, 0.2 and 5 μg/L) for 30 days to assess its neurotoxicity. Results revealed that FLZ disrupted the balance of gut microbiota and caused an increase in pathogenic bacteria, such as Paracoccus and Aeromonas, leading to pathological damage to the intestine. The upregulation of intestinal pro-inflammatory factors, IL-1β and TNF-α, by 2.4 and 6.3 times, respectively, along with the downregulation of tight junction proteins, Occludin and zonula occludens 1 (ZO-1), by 80 % and 50 %, increased in intestinal permeability. Moreover, untargeted metabolomics demonstrated that FLZ interfered with intestinal nucleotide metabolism and amino acid biosynthesis. FLZ could also increase the levels of lipopolysaccharide (LPS) and malondialdehyde (MDA) in the brain by 0.9 and 3.4 times, respectively, leading to pathological changes in brain tissue. Furthermore, FLZ significantly disturbed nucleotide metabolism and amino acid biosynthesis and metabolism pathways in the brain. Correlation analysis between gut microbiota and neurochemicals confirmed that FLZ can induce neurotoxicity through the microbiota-gut-brain axis. These findings elucidate the molecular mechanisms of psychoactive drugs on microbiota-gut-brain axis and provide a theoretical basis for the ecological environmental risk assessment of various psychoactive substances.

Warmer temperature overrides the effects of antidepressants on amphibian metamorphosis and behavior

Climate change can exacerbate the effects of environmental pollutants on aquatic organisms. Pollutants such as human antidepressants released from wastewater treatment plants have been shown to impact life-history traits of amphibians. We exposed tadpoles of the wood frog Lithobates sylvaticus to two temperatures (20 °C and 25 °C) and two antidepressants (fluoxetine and venlafaxine), and measured timing of metamorphosis, mass at metamorphosis, and two behaviors (startle response and percent motionless). Antidepressants significantly shortened time to metamorphosis at 20 °C, but not at 25 °C. At 25 °C, tadpoles metamorphosed significantly faster than those at 20 °C independent of antidepressant exposure. Venlafaxine reduced body mass at 25 °C, but not at 20 °C. Temperature and antidepressant exposure affected the percent of tadpoles showing a startle response. Tadpoles at 20 °C displayed significantly more responses than at 25 °C. Exposure to fluoxetine also increased the percent of tadpoles showing a startle response. Venlafaxine reduced the percent of motionless tadpoles at 25 °C but not at 20 °C. While our results showed that antidepressants can affect the timing of metamorphosis in tadpoles, warmer temperatures overrode these effects and caused a reduction in an important reaction behavior (startle response). Future studies should address how warmer global temperatures may exacerbate or negate the effects of environmental pollutants.

Comparative subcellular responses to pharmaceutical exposures in the mussel Mytilus galloprovincialis: An in vitro study

Pharmaceutical active compounds (PhACs) have raised concerns in the last decade due to their increased consumption and inadequate elimination during discharge, resulting in their introduction into water systems and potential significant threats to non-target organisms. However, few studies have investigated the sublethal impacts of PhAC exposure on marine invertebrates. Thus, the present study aimed to assess tissue-specific responses in Mytilus galloprovincialis to sodium lauryl sulfate (SLS), salicylic acid (SA), and caffeine (CAF) (4.0 mg/L, 4.0 mg/L and 2.0 μg/L, respectively). Short-term in vitro exposures with mussel digestive gland and gill tissues were conducted and biochemical responses related to antioxidant and detoxification capacity, cellular damage and neurotoxicity were assessed. The present results clearly showed significant differences in tissue sensitivity and biochemical responses to the contaminants tested. This study highlights the suitability of filter-feeder species as valuable model organisms for studying the sublethal effects of unintended environmental exposures to PhACs.

The role of temperature on zebrafish ontogenic development and sensitivity to pharmaceuticals

This study assessed the effects of two emerging environmental pollutants caffeine (CAF) and metformin (METF) on juvenile zebrafish, raised at 22 °C or 27 ºC, after 96 h exposure. The temperature influenced the basal behaviour of unexposed juveniles, with higher swimming activity and a greater percentage of movements at the well edges observed in fish raised at 27 °C. A significant interaction between CAF and temperature was found for behavioural endpoints, but not for AChE activity, associated with neurotoxicity effects. CAF reduced swimming distance, increased erratic swimming, and inhibited AChE activity at 22 ºC, while at 27 ºC, CAF did not affect behaviour but increased AChE. METF exposure at 22 °C decreased swimming distance and increased erratic movements, but at 27 °C no effects were detected. Overall, temperature plays a more important role in the effects induced by CAF than METF.

UV polymerization fabrication method for polymer composite based optical fiber sensors

Optical fiber (OF) sensors are critical optical devices with excellent sensing capabilities and the capacity to operate in remote and hostile environments. However, integrating functional materials and micro/nanostructures into the optical fiber systems for specific sensing applications has limitations of compatibility, readiness, poor control, robustness, and cost-effectiveness. Herein, we have demonstrated the fabrication and integration of stimuli-responsive optical fiber probe sensors using a novel, low-cost, and facile 3D printing process. Thermal stimulus-response of thermochromic pigment micro-powders was integrated with optical fibers by incorporating them into ultraviolet-sensitive transparent polymer resins and then printed via a single droplet 3D printing process. Hence, the thermally active polymer composite fibers were grown (additively manufactured) on top of the commercial optical fiber tips. Then, the thermal response was studied within the temperature range of (25-35 °C) and (25-31 °C) for unicolor and dual color pigment powders-based fiber-tip sensors, respectively. The unicolor (with color to colorless transition) and dual color (with color to color transition) powders-based sensors exhibited substantial variations in transmission and reflection spectra by reversibly increasing and decreasing temperatures. The sensitivities were calculated from the transmission spectra where average change in transmission spectra was recorded as 3.5% with every 1 °C for blue, 3% for red and 1% for orange-yellow thermochromic powders based optical fiber tip sensors. Our fabricated sensors are cost-effective, reusable, and flexible in terms of materials and process parameters. Thus, the fabrication process can potentially develop transparent and tunable thermochromic sensors for remote sensing with a much simpler manufacturing process compared to conventional and other 3D printing processes for optical fiber sensors. Moreover, this process can integrate micro/nanostructures as patterns on the optical fiber tips to increase sensitivity. The developed sensors may be employed as remote temperature sensors in biomedical and healthcare applications.

Addressing chemical pollution in biodiversity research

Climate change, biodiversity loss, and chemical pollution are planetary-scale emergencies requiring urgent mitigation actions. As these "triple crises" are deeply interlinked, they need to be tackled in an integrative manner. However, while climate change and biodiversity are often studied together, chemical pollution as a global change factor contributing to worldwide biodiversity loss has received much less attention in biodiversity research so far. Here, we review evidence showing that the multifaceted effects of anthropogenic chemicals in the environment are posing a growing threat to biodiversity and ecosystems. Therefore, failure to account for pollution effects may significantly undermine the success of biodiversity protection efforts. We argue that progress in understanding and counteracting the negative impact of chemical pollution on biodiversity requires collective efforts of scientists from different disciplines, including but not limited to ecology, ecotoxicology, and environmental chemistry. Importantly, recent developments in these fields have now enabled comprehensive studies that could efficiently address the manifold interactions between chemicals and ecosystems. Based on their experience with intricate studies of biodiversity, ecologists are well equipped to embrace the additional challenge of chemical complexity through interdisciplinary collaborations. This offers a unique opportunity to jointly advance a seminal frontier in pollution ecology and facilitate the development of innovative solutions for environmental protection.

Bioconcentration of pharmaceuticals in benthic marine organisms (Holothuria tubulosa, Anemonia sulcata and Actinia equina) exposed to environmental contamination by atenolol and carbamazepine

The present work assess the bioconcentration kinetics of atenolol (ATN) and carbamazepine (CBZ) in common marine organisms including Holothuria tubulosa, Anemonia sulcata and Actinia equina under controlled laboratory conditions. CBZ exhibited higher uptake and excretion rates resulting higher bioconcentration factor (BCF) (41-537L/kg for CBZ vs 7-50L/kg for ATN) although both are below the limits established by the European Union (EU). The measured BCF using kinetic data showed some differences with those predicted using the concentrations measured at the steady-state, probably explained because the steady state was not ready reached. The animal-specific BCF followed the order of Holothuria tubulosa >Actinia equina >Anemonia sulcata for ATN while was the opposite for CBZ. The study highlighted between-tissues differences in the digestive tract and the body wall of the Holothuria tubulosa. The work presented is the first to model bioconcentration of ATN and CBZ in holothurian and anemone animal models.

Bioconcentrations, depuration, shift in metabolome and a behavioural response in the nymphs of the dragonfly Aeshna cyanea (Müller, 1764) to environmentally relevant concentrations of methamphetamine

Methamphetamine (MEA) is commonly detected in municipal wastewater. It causes imbalances in the system of neurotransmitters as well as several other adverse effects on human health. The aim of this study was to investigate bioconcentration and depuration rates at an environmentally relevant concentration of 1 µg·L^-1 in Aeshna cyanea nymphs exposed to MEA for six days followed by three days of depuration. The metabolomes of nymphs sampled during exposure and depuration were compared using non-targeted screening. Concurrently, a behavioural experiment was run to evaluate the effect of MEA on movement. Since most samples were below the limits of quantification (LOQs) - MEA was quantified in only four out of the 87 samples and only during the first 24 h of exposure at concentrations at LOQ level - we estimated maximal possible bioconcentration factor (BCF) on 0.63 using the LOQ. An MEA metabolite - amphetamine - was not detected in any sample at levels above their LOQs. From 247 up to 1458 significant down- and up-regulated metabolite signals (p ≤ 0.05) were detected by non-targeted screening during initial times of exposure and depuration. Numbers of significant down- and/or up-regulated signals in metabolomes (p ≤ 0.05) calculated for particular sampling times possibly correlated with the size of the effect on movement recorded at the same times. In the MEA treatment, movement was not significantly greater during exposure (p > 0.05) but was significantly lower during depuration (p < 0.05). This study shows how MEA acts on dragonfly nymphs, an ecologically important group of aquatic insects with a high trophic level.

Warming Affects Bioconcentration and Bioaccumulation of Per- and Polyfluoroalkyl Substances by Pelagic and Benthic Organisms in a Water-Sediment System

Warming and exposure to emerging global pollutants, such as per- and polyfluoroalkyl substances (PFAS), are significant stressors in the aquatic ecosystem. However, little is known about the warming effect on the bioaccumulation of PFAS in aquatic organisms. In this study, the pelagic organisms Daphnia magna and zebrafish, and the benthic organism Chironomus plumosus were exposed to 13 PFAS in a sediment-water system with a known amount of each PFAS at different temperatures (16, 20, and 24 °C). The results showed that the steady-state body burden (C_b-ss) of PFAS in pelagic organisms increased with increasing temperatures, mainly attributed to increased water concentrations. The uptake rate constant (k_u) and elimination rate constant (k_e) in pelagic organisms increased with increasing temperature. In contrast, warming did not significantly change or even mitigate C_b-ss of PFAS in the benthic organism Chironomus plumosus, except for PFPeA and PFHpA, which was consistent with declined sediment concentrations. The mitigation could be explained by the decreased bioaccumulation factor due to a more significant percent increase in k_e than k_u, especially for long-chain PFAS. This study suggests that the warming effect on the PFAS concentration varies among different media, which should be considered for their ecological risk assessment under climate change.

Speed it up: How temperature drives toxicokinetics of organic contaminants in freshwater amphipods

The acceleration of global climate change draws increasing attention towards interactive effects of temperature and organic contaminants. Many studies reported a higher sensitivity of aquatic invertebrates towards contaminant exposure with increasing or fluctuating temperatures. The hypothesis of this study was that the higher sensitivity of invertebrates is associated with the changes of toxicokinetic processes that determine internal concentrations of contaminants and consequently toxic effects. Therefore, the influence of temperature on toxicokinetic processes and the underlying mechanisms were studied in two key amphipod species (Gammarus pulex and Hyalella azteca). Bioconcentration experiments were carried out at four different temperatures with a mixture of 12 exposure relevant polar organic contaminants. Tissue and medium samples were taken in regular intervals and analysed by online solid-phase extraction liquid chromatography high-resolution tandem mass spectrometry. Subsequently, toxicokinetic rates were modelled and analysed in dependence of the exposure temperature using the Arrhenius equation. An exponential relationship between toxicokinetic rates versus temperature was observed and could be well depicted by applying the Arrhenius equation. Due to a similar Arrhenius temperature of uptake and elimination rates, the bioconcentration factors of the contaminants were generally constant across the temperature range. Furthermore, the Arrhenius temperature of the toxicokinetic rates and respiration was mostly similar. However, in some cases (citalopram, cyprodinil), the bioconcentration factor appeared to be temperature dependent, which could potentially be explained by the influence of temperature on active uptake mechanisms or biotransformation. The observed temperature effects on toxicokinetics may be particularly relevant in non-equilibrated systems, such as exposure peaks in summer as exemplified by the exposure modelling of a field measured pesticide peak where the internal concentrations increased by up to fourfold along the temperature gradient. The results provide novel insights into the mechanisms of chemical uptake, biotransformation and elimination in different climate scenarios and can improve environmental risk assessment.

Bioaccumulation/bioconcentration of pharmaceutical active compounds in aquatic organisms: Assessment and factors database

There is increasing evidence that the presence of certain pharmaceuticals in the environment leads to biota exposure and constitute a potential risk for ecosystems. Bioaccumulation is an essential focus of risk assessment to evaluate at what degree emerging contaminants are a hazard both to the environment and the individuals that inhabit it. The main goals of the present review are 1) to summarize and describe the research and factors that should be taken into account in the evaluation of bioaccumulation of pharmaceuticals in aquatic organisms; and 2) to provide a database and a critical review of the bioaccumulation/bioconcentration factors (BAF or BCF) of these compounds in organisms of different trophic levels. Most studies fall into one of two categories: laboratory-scale absorption and purification tests or field studies and, to a lesser extent, large-scale, semi-natural system tests. Although in the last 5 years there has been considerable progress in this field, especially in species of fish and molluscs, research is still limited on other aquatic species like crustaceans or algae. This revision includes >230 bioconcentration factors (BCF) and >530 bioaccumulation factors (BAF), determined for 113 pharmaceuticals. The most commonly studied is the antidepressant group, followed by diclofenac and carbamazepine. There is currently no reported accumulation data on certain compounds, such as anti-cancer drugs. BCFs are highly influenced by experimental factors (notably the exposure level, time or temperature). Field BAFs are superior to laboratory BCFs, highlighting the importance of field studies for reliable assessments and in true environmental conditions. BAF data appears to be organ, species and compound-specific. The potential impact on food web transfer is also considered. Among different aquatic species, lower trophic levels and benthic organisms exhibit relatively higher uptake of these compounds.

The effect of temperature on toxicokinetics and the chronic toxicity of insecticides towards Gammarus pulex

A comprehensive understanding of chemical toxicity and temperature interaction is essential to improve ecological risk assessment under climate change. However, there is only limited knowledge about the effect of temperature on the toxicity of chemicals. To fill this knowledge gap and to improve our mechanistic understanding of the influence of temperature, the current study explored toxicokinetics and the chronic toxicity effects of two insecticides, imidacloprid (IMI) and flupyradifurone (FPF), on Gammarus pulex at different temperatures (7-24 °C). In the toxicokinetics tests, organisms were exposed to IMI or FPF for 2 days and then transferred to clean water for 3 days of elimination at 7, 18, or 24 °C. In the chronic tests, organisms were exposed to the individual insecticides for 28 days at 7, 11, or 15 °C. Our research found that temperature impacted the toxicokinetics and the chronic toxicity of both IMI and FPF, while the extent of such impact differed for each insecticide. For IMI, the uptake rate and biotransformation rate increased with temperature, and mortality and food consumption inhibition was enhanced by temperature. While for FPF, the elimination rate increased with temperature at a higher rate than the increasing uptake rate, resulting in a smaller pronounced effect of temperature on mortality compared to IMI. In addition, the adverse effects of the insecticides on sublethal endpoints (food consumption and dry weight) were exacerbated by elevated temperatures. Our results highlight the importance of including temperature in the ecological risk assessment of insecticides in light of global climate change.

Influence of time-dependent sampling on fish plasma levels of select pharmaceuticals and per- and polyfluoroalkyl substances (PFASs)

Determining pharmaceutical levels in fish plasma represents an increasingly valuable approach for environmental assessments of pharmaceuticals. These fish plasma observations are compared to human therapeutic plasma doses because of the high evolutionary conservation of many drug targets among vertebrates. In the present study, we initially identified highly variable information regarding plasma sampling practices in the literature and then tested the hypothesis that fish plasma levels of selected pharmaceuticals and per- and polyfluoroalkyl substances (PFASs) would not change with time to process samples from the field. After common carp were placed in a wastewater-fed pond for one month, we immediately sampled fish plasma nonlethally in the field or after transferring fish to clean water and held them under these conditions for either 3 or 20 h. We then quantitated pharmaceuticals in water, and pharmaceuticals and PFASs in plasma by LC-MSMS. Whereas plasma levels of most pharmaceuticals decreased even after 3 h that fish spent in clean water, plasma concentrations of the PFASs examined here remained stable over 20 h. Collectively, our examination of these time-dependent sampling approaches and associated findings highlight the importance of appropriate and consistent sampling for bioaccumulation studies, biomonitoring activities, and aquaculture product safety evaluations.

Bioaccumulation potential of the tricyclic antidepressant amitriptyline in a marine Polychaete, Nereis virens

The continual discharge of pharmaceuticals from wastewater treatment plants (WWTPs) into the marine environment, even at concentrations as low as ng/L, can exceed levels that induce sublethal effects to aquatic organisms. Amitriptyline, a tricyclic antidepressant, is the most prescribed antidepressant in Norway, though the presence, potential for transport, and uptake by aquatic biota have not been assessed. To better understand the release and bioaccumulative capacity of amitriptyline, laboratory exposure studies were carried out with field-collected sediments. Influent and effluent composite samples from the WWTP of Stavanger (the 4th largest city in Norway) were taken, and sediment samples were collected in three sites in the proximity of this WWTP discharge at sea (WWTP discharge (IVAR), Boknafjord, and Kvitsøy (reference)). Polychaetes (Nereis virens) were exposed to field-collected sediments, as well as to Kvitsøy sediment spiked with 3 and 30 μg/g amitriptyline for 28 days. The WWTP influent and effluent samples had concentrations of amitriptyline of 4.93 ± 1.40 and 6.24 ± 1.39 ng/L, respectively. Sediment samples collected from IVAR, Boknafjord, and Kvitsøy had concentrations of 6.5 ± 3.9, 15.6 ± 12.7, and 12.7 ± 8.0 ng/g, respectively. Concentrations of amitriptyline were below the limit of detection in polychaetes exposed to sediment collected from Kvitsøy and IVAR, and 5.2 ± 2.8 ng/g in those exposed to Boknafjord sediment. Sediment spiked with 3 and 30 μg/g amitriptyline had measured values of 423.83 ± 33.1 and 763.2 ± 180.5 ng/g, respectively. Concentrations in worms exposed to the amended sediments were 9.5 ± 0.2 and 56.6 ± 2.2 ng/g, respectively. This is the first known study to detect measurable concentrations of amitriptyline in WWTP discharge in Norway and accumulation in polychaetes treated with field-collected sediments, suggesting that amitriptyline has the potential for trophic transfer in marine systems.

Bioaccumulation and bioamplification of pharmaceuticals and endocrine disruptors in aquatic insects

Environmental fate of emerging contaminants such as pharmaceuticals and endocrine disrupting compounds at the aquatic terrestrial boundary are largely unexplored. Aquatic insects connect aquatic and terrestrial food webs as their life cycle includes aquatic and terrestrial life stages, thus they represent an important inter-habitat linkage not only for energy and nutrient flow, but also for contaminant transfer to terrestrial environments. We measured the concentrations of pharmaceuticals and endocrine disrupting compounds in the larval and adult tissues (last larval stages and teneral adults) of five Odonata species sampled in a wastewater-impacted river, in order to examine their bioaccumulation and bioamplification at different taxonomic levels. Twenty different compounds were bioaccumulated in insect tissues, with majority having higher concentrations (up to 90% higher) in aquatic larvae compared to terrestrial adults (reaching 88 ng/g for 1H-benzotriazole). However, increased concentration in adults was observed for seven compounds in at least one suborder (41% of the accumulated), confirming contaminants bioamplification across the metamorphosis. Both, bioaccumulation and bioamplification differed at various taxa levels; the order (Odonata), suborder (Anisoptera and Zygoptera) and species level. Highest variability was observed between Anisoptera and Zygoptera, due to the underlying differences in their ecology. Generally, Zygoptera had higher concentrations of contaminants in both larvae and adults. Additionally, we aimed at predicting effects of contaminant properties on bioaccumulation and bioamplification patterns using the commonly used physicochemical and pharmacokinetic descriptors on both order and suborder levels, however, neither of the two processes could be consistently predicted with simple linear models. Our study highlights the importance of taxonomy in studies aiming at advancing the understanding of contaminant exchange between aquatic and terrestrial food webs, as higher taxonomic categories include ecologically diverse groups, whose contribution to "the dark side of subsidies" could substantially differ.

Antibiotics in Raw Meat Samples: Estimation of Dietary Exposure and Risk Assessment

The extensive use of antibiotics in livestock farming poses increased concerns for human health as residues of these substances are present in edible tissues. The aim of this study was the determination of the levels of four groups of antibiotics (sulfonamides-SAs, tetracyclines-TCs, streptomycines-STr and quinolones-QNLs) in meat samples (muscles, livers and kidneys from beef, chicken and pork) and the estimation of the dietary exposure to antibiotics from meat consumption and the potential hazard for human health. Fifty-four samples of raw meat were randomly collected in 2018 from the Cretan market, Greece and analyzed both with an enzyme-linked immunosorbent assay (ELISA) and liquid chromatography-mass spectrometry (LC-MS). According to the results derived from the ELISA method, only 2% of the meat samples were free from antibiotics, 2% were detected with 4 antibiotics and the great majority of the samples (87%) were detected with 2 to 3 antibiotics. SAs presented the highest detection frequencies for all samples whereas TCs were not detected in any bovine sample. The highest median concentration was detected for STr in bovine muscles (182.10 μg/kg) followed by QNLs (93.36 μg/kg) in pork kidneys whereas the chicken samples had higher burdens of QNLs compared to the other meat samples. LC-MS analysis showed that oxytetracycline (OTC) was the most common antibiotic in all samples. The highest median concentration of all antibiotics was detected for doxycycline (DOX) (181.73 μg/kg in pork kidney) followed by OTC in bovine liver (74.46 μg/kg). Risk characterization was applied for each of the two methods; The hazard quotients (HQ) did not exceed 0.059 for the ELISA method and 0.113 for the LC-MS method for any group of antibiotics, whereas the total hazard indexes (HI) were 0.078 and 0.021, respectively. The results showed the presence of different groups of antibiotics in meat from the Cretan market and that the health risk to antibiotics is low. A risk assessment analysis conducted for meat consumption and corrected for the aggregated exposure revealed no risk for the consumers.

Comparison of cellular mechanisms induced by pharmaceutical exposure to caffeine and its combination with salicylic acid in mussel Mytilus galloprovincialis

Urban and hospital-sourced pharmaceuticals are continuously discharged into aquatic environments, threatening biota. To date, their impact as single compounds has been widely investigated, whereas few information exists on their effects as mixtures. We assessed the time-dependent biological impact induced by environmental concentrations of caffeine alone (CAF; 5 ng/L to 10 µg/L) and its combination with salicylic acid (CAF+SA; 5 ng/L+0.05 µg/L to 10 µg/L+100 µg/L) on gills of mussel Mytilus galloprovincialis during a 12-day exposure. Although no histological alteration was observed in mussel gills, haemocyte infiltration was noticed at T12 following CAF+SA exposure, as confirmed by flow cytometry with increased hyalinocytes. Both the treatments induced lipid peroxidation and cholinergic neurotoxicity, which the antioxidant system was unable to counteract. We have highlighted the biological risks posed by pharmaceuticals on biota under environmental scenarios, contributing to the enhancement of ecopharmacovigilance programmes and amelioration of the efficacy of wastewater treatment plants.

Pharmaceuticals in the Aquatic Environment: A Review on Eco-Toxicology and the Remediation Potential of Algae

The pollution of the aquatic environment has become a worldwide problem. The widespread use of pesticides, heavy metals and pharmaceuticals through anthropogenic activities has increased the emission of such contaminants into wastewater. Pharmaceuticals constitute a significant class of aquatic contaminants and can seriously threaten the health of non-target organisms. No strict legal regulations on the consumption and release of pharmaceuticals into water bodies have been implemented on a global scale. Different conventional wastewater treatments are not well-designed to remove emerging contaminants from wastewater with high efficiency. Therefore, particular attention has been paid to the phycoremediation technique, which seems to be a promising choice as a low-cost and environment-friendly wastewater treatment. This technique uses macro- or micro-algae for the removal or biotransformation of pollutants and is constantly being developed to cope with the issue of wastewater contamination. The aims of this review are: (i) to examine the occurrence of pharmaceuticals in water, and their toxicity on non-target organisms and to describe the inefficient conventional wastewater treatments; (ii) present cost-efficient algal-based techniques of contamination removal; (iii) to characterize types of algae cultivation systems; and (iv) to describe the challenges and advantages of phycoremediation.

In vitro-in vivo biotransformation and phase I metabolite profiling of benzo[a]pyrene in Gulf killifish (Fundulus grandis) populations with different exposure histories

Chronic exposure to pollution may lead populations to display evolutionary adaptations associated with cellular and physiological mechanisms of defense against xenobiotics. This could result in differences in the way individuals of the same species, but inhabiting different areas, cope with chemical exposure. In the present study, we explore two Gulf killifish (Fundulus grandis) populations with different exposure histories for potential differences in the biotransformation of benzo[a]pyrene (BaP), and conduct a comparative evaluation of in vitro and in vivo approaches to describe the applicability of new approach methodologies (NAMs) for biotransformation assessments. Pollution-adapted and non-adapted F. grandis were subjected to intraperitoneal (IP) injections of BaP in time-course exposures, prior to measurements of CYP biotransformation activity, BaP liver concentrations, and the identification and quantification of phase I metabolites. Additionally, substrate depletion bioassays using liver S9 fractions were employed for measurements of intrinsic hepatic clearance and to evaluate the production of metabolites in vitro. Pollution-adapted F. grandis presented significantly lower CYP1A activity and intrinsic clearance rates that were 3 to 4 times lower than non-adapted fish. The metabolite profiling of BaP showed the presence of 1‑hydroxy-benzo[a]pyrene in both the in vitro and in vivo approaches but with no significant population differences. Contrarily, 9‑hydroxy-benzo[a]pyrene and benzo[a]pyrene-4,5-dihydrodiol, only identified through the in vivo approach, presented higher concentrations in the bile of pollution-adapted fish relative to non-adapted individuals. These observations further the understanding of the evolutionary adaptation of F. grandis inhabiting heavily polluted environments in the Houston Ship Channel, TX, USA, and highlight the need to consider the evolutionary history of populations of interest during the implementation of NAMs.