Short-term effects of an environmentally relevant concentration of organic UV filters on signal crayfish Pacifastacus leniusculus.

Personal care products, including organic UV filters, are considered emerging contaminants, with their toxic effects being a concern in recent decades. UV filters continually enter surface waters via wastewater and human activity. Despite the presence of organic UV filters in the freshwater environment, little is known of their impact on aquatic biota. In this study, we evaluated the cardiac and locomotor responses of signal crayfish Pacifastacus leniusculus exposed to environmentally relevant concentrations of either 2-Phenylbenzimidazole-5-sulfonic acid (PBSA, 3 µg/L) or 5-Benzoyl-4-hydroxy-2-methoxybenzenesulfonic acid (BP4, 2.5 µg/L). Specimens exposed to the tested compounds for 30 min exhibited significantly greater changes in distance moved and time active than did unexposed controls. Significant differences of mean heart rate change compared to control were detected in both PBSA and BP4 experimental groups. Such behavior and physiological alterations demonstrate ecological effects of personal care products with the tested sunscreen compounds even with a short exposure. Evidence of the consequences of organic UV filters on aquatic organisms is scarce and is an important topic for future research.

Effect of psychoactive substances on cardiac and locomotory activity of juvenile marbled crayfish Procambarus virginalis.

Pharmaceutically active compounds are common and increasing in the aquatic environment. Evidence suggests they have adverse effects on non-target organisms, and they are classified as emerging pollutants for a variety of aquatic organisms. To determine the effects of environmentally relevant levels of psychoactive compounds on non-target organisms, we analyzed cardiac and locomotory activity in early developmental stages of marbled crayfish Procambarus virginalis. Responses to sertraline, methamphetamine, and a mixture of citalopram, oxazepam, sertraline, tramadol, venlafaxine, and methamphetamine at a concentration of 1 µg L-1 of each compound were assessed. On day four of exposure, cardiac activity was recorded for 5 min, and on day eight, locomotory activity was recorded for 15 min. There was a significant increase (p < 0.01) in heart rate in methamphetamine-exposed and Mix-exposed juveniles compared to the unexposed control and there was significant difference (p < 0.01) in proportion of time (activity %) was observed with sertraline-exposed, whereas velocity, and distance moved did not significantly differ (p > 0.05) in exposed and control animals. These findings revealed that low concentrations of chemicals and their mixtures can modify the physiological state of aquatic animals without outward manifestations (activity, distance moved, and velocity). Aquatic animals can be impacted earlier than is visible, but effects can potentially lead to substantial changes in populations and in ecosystem processes. Additional research to investigate chemical combinations, exposure systems, and organism physiological and molecular responses may provide evidence of broad impact of environmental pharmaceuticals.

Methamphetamine pollution elicits addiction in wild fish.

Illicit drug abuse presents pervasive adverse consequences for human societies around the world. Illicit drug consumption also plays an unexpected role in contamination of aquatic ecosystems that receive wastewater discharges. Here, we show that methamphetamine, considered as one of the most important global health threats, causes addiction and behavior alteration of brown trout Salmo trutta at environmentally relevant concentrations (1 µg l-1). Altered movement behavior and preference for methamphetamine during withdrawal were linked to drug residues in fish brain tissues and accompanied by brain metabolome changes. Our results suggest that emission of illicit drugs into freshwater ecosystems causes addiction in fish and modifies habitat preferences with unexpected adverse consequences of relevance at the individual and population levels. As such, our study identifies transmission of human societal problems to aquatic ecosystems.

Searching for the correlations between the use of different groups of pharmaceuticals from wastewaters.

Wastewater contains a wealth of information about the inhabitants of cities. Wastewater-based epidemiology (WBE) has become an effective tool for monitoring public health by analyzing various biomarkers (e.g., chemicals and microorganisms) in wastewater. This way, the estimation of pharmaceuticals' consumption behavior and/or illicit drugs can be calculated. However, monitoring consumption alone is not the only option. If we consider wastewater as a statistical representation of the population's health, medical information can be derived. In this work, we used data from 15 different wastewater treatment plants in Slovak Republic to explore correlations between the use of typical pharmaceuticals and illicit drugs. The analysis was based on the wastewater monitoring data from four years (2016-2019), and 68 different compounds were taken into account. One of the strongest correlations found was between Antihyperlipidemics and Antihypertensives, with Pearson's correlation coefficient of 0.82. This type of analysis within the WBE represents a new potential as an additional source of information for the pharmaceutical, medical and government sectors in assessing health risk factors in the population. Such an evaluation method has even a great potential for artificial intelligence and machine learning for calculating health risk factors together with other sources of data.

Prescribed aggression of fishes: Pharmaceuticals modify aggression in environmentally relevant concentrations.

Traces of psychoactive substances have been found in freshwaters globally. Fish are chronically exposed to pollution at low concentrations. The changes of aggressive behaviour of chub (Squalius cephalus) were determined under the exposure to four psychoactive compounds (sertraline, citalopram, tramadol, methamphetamine) at environmentally relevant concentrations of 1 µg/L for 42 days. We tested whether (A) the behavioural effect of compounds varies within a single species; (B) there is a correlation between the individual brain concentration of the tested pollutants and fish aggression using the novel analysis of pollutants in brain; and (C) there is detectable threshold to effective pollutant concentration in brain. Behaviour and pollutant concentrations in brain were determined repeatedly (1st, 7th, 21st, 42nd and 56th days), including a two-week-long depuration period. The effect of particular compounds varied. Citalopram and methamphetamine generally increased the fish aggression, while no such effect was found after exposure to tramadol or sertraline. The longitudinal analysis showed an aggression increase after depuration, indicating the presence of withdrawal effects in methamphetamine- and tramadol-exposed fish. The analysis of pollutant concentration in brain revealed a positive linear relationship of citalopram concentration and aggression, while no such effect was detected for other compounds and/or their metabolites. Structural break analyses detected concentration thresholds of citalopram (1 and 3 ng/g) and sertraline (1000 ng/g) in brain tissue, from which a significant effect on behaviour was manifested. While the effect of sertraline was not detected using traditional approaches, there was a reduction in aggression after considering its threshold concentration in the brain. Our results suggest that pursuing the concentration threshold of psychoactive compounds can help to reduce false negative results and provide more realistic predictions on behavioural outcomes in freshwater environments, especially in the case of compounds with bioaccumulation potential such as sertraline.

Traces of tramadol in water impact behaviour in a native European fish.

Tramadol is a widely used analgesic with additional antidepressant and anxiolytic effects. This compound has been reported in continental waters reaching concentrations of µg/L as a consequence of its inefficient removal in sewage treatment plants and increasing use over time. In this study, European chubs (Squalius cephalus) were exposed to 1 µg/L of tramadol in water for 42 days with a subsequent 14 days of depuration. Our results revealed that chubs exposed to this analgesic underwent changes in their behaviour as compared to the control group. The behavioural outcome was also influenced by the individual concentration of tramadol in brain tissue. In particular, experimental fish presented anxiolytic-like effects, characterized by less bold and less social individuals. Exposed animals were less frequently out of the shelter and moved a shorter distance, indicating that they explored the new environment less during the boldness test. In the novel object recognition experiment, although they distinguished the new item, they examined it less and displayed a reduced activity. Shoal cohesion was disrupted as observed in an increased distance between individuals. After the depuration phase, this alteration remained whereas the boldness effect disappeared. Moreover, the degree of behavioural changes was correlated with the concentration of the substance in brain. According to our findings, chronic presence of tramadol in the environment can impact the fitness of exposed aquatic fauna by altering evolutionary crucial behaviours.

Determination of citalopram in fish brain tissue: benefits of coupling laser diode thermal desorption with low- and high-resolution mass spectrometry.

Recent state-of-the-art methods developed for the analysis of polar xenobiotics from different types of biological matrices usually employ liquid chromatography with mass spectrometry. However, there are limitations when a small amount of sample mass is available. For example, individual benthic invertebrates or fish tissue samples often weigh less than 100 mg (e.g., brain, liver) but are necessary to understand environmental fate and bioaccumulation dynamics. We developed ultra-fast methods based on a direct sample introduction technique. This included coupling laser diode thermal desorption with atmospheric pressure chemical ionization mass spectrometry (LDTD-APCI-MS). We then quantitated a common selective serotonin reuptake inhibitor (citalopram) in brain tissues of individual juvenile fish after in vivo exposure to environmentally relevant concentration. Two mass spectrometric methods based on low (LDTD-APCI-triple quadrupole (QqQ)-MS/MS) and high (LDTD-APCI-high-resolution product scan (HRPS)) resolutions were developed and evaluated. Individual instrument conditions were optimized to achieve an accurate and robust analytical method with minimum sample preparation requirements. We achieved very good recovery (97-108%) across the range of 1-100 ng g-1 for LDTD-APCI-HRPS. LDTD-APCI-QqQ-MS/MS showed poorer performance due to interferences from the matrix at the lowest concentration level. LDTD-APCI ionization was successfully validated for analysis of non-filtered sample extracts. Evaluation of final methods was performed for a set of real fish brain samples, including comparison of LDTD-APCI-HRPS with a previously validated LC-heated electrospray ionization-HRPS method. This new LDTD-APCI-HRPS method avoids the chromatographic step and provides important benefits such as analysis of limited sample masses, lower total sample volume (typically µL), and reduction in analysis time per sample run to a few seconds. Graphical abstract.

In Vitro Metabolic Transformation of Pharmaceuticals by Hepatic S9 Fractions from Common Carp (Cyprinus carpio).

Water from wastewater treatment plants contains concentrations of pharmaceutically active compounds as high as micrograms per liter, which can adversely affect fish health and behavior, and contaminate the food chain. Here, we tested the ability of the common carp hepatic S9 fraction to produce the main metabolites from citalopram, metoprolol, sertraline, and venlafaxine. Metabolism in fish S9 fractions was compared to that in sheep. The metabolism of citalopram was further studied in fish. Our results suggest a large difference in the rate of metabolites formation between fish and sheep. Fish hepatic S9 fractions do not show an ability to form metabolites from venlafaxine, which was also the case for sheep. Citalopram, metoprolol, and sertraline were metabolized by both fish and sheep S9. Citalopram showed concentration-dependent N-desmethylcitalopram formation with Vmax = 1781 pmol/min/mg and Km = 29.7 µM. The presence of ellipticine, a specific CYP1A inhibitor, in the incubations reduced the formation of N-desmethylcitalopram by 30-100% depending on the applied concentration. These findings suggest that CYP1A is the major enzyme contributing to the formation of N-desmethylcitalopram. In summary, the results from the present in vitro study suggest that common carp can form the major metabolites of citalopram, metoprolol, and sertraline.

Effects of Multi-Component Mixtures from Sewage Treatment Plant Effluent on Common Carp (Cyprinus carpio) under Fully Realistic Condition.

This study characterized changes in biomarker responses in common carp (Cyprinus carpio) upon exposure to effluent water discharged from a sewage treatment plant (STP) under real conditions. Fish were exposed to contamination in Cezarka pond, which receives all of its water input from the STP in the town of Vodnany, Czech Republic. Five sampling events were performed at day 0, 30, 90, 180, and 360 starting in April 2015. In total, 62 pharmaceutical and personal care products (PPCPs) were detected in the polar organic chemical integrative sampler. Compared to a control pond, the total concentration of PPCPs was 45, 16, 7, and 7 times higher in Cezarka pond at day 30, 90, 180, and 360, respectively. The result of oxidative stress and antioxidant enzyme biomarkers indicated alterations in the liver and intestine tissues of fish from Cezarka pond at day 30 and 360, respectively. High plasma vitellogenin levels were observed in both exposed females (180 and 360 days) and males (360 days) compared with their respective controls. However, only exposed female fish had higher vitellogenin mRNA expression than the control fish in these periods. Exposed female fish showed irregular structure of the ovary with scattered oocytes, which further developed to a vitellogenic stage at day 360. Low white blood cell levels were indicated in all exposed fish. Despite numerous alterations in exposed fish, favorable ecological conditions including high availability of food resulted in a better overall condition of the exposed fish after 1 year of exposure compared to the controls.

Correction to: Effects of multi-component mixtures from sewage treatment plant effluent on common carp (Cyprinus carpio) under fully realistic condition.

The original version of this Article unfortunately contained an error. The authors' given and family names were transposed erroneously. It has been corrected now in this Erratum.

Investigation of diltiazem metabolism in fish using a hybrid quadrupole/orbital trap mass spectrometer.

RATIONALE: Diltiazem, a calcium channel blocker drug, is widespread in the environment because of its incomplete elimination during water treatment. It can cause negative effects on aquatic organisms; thus, a rapid and sensitive liquid chromatography/mass spectrometry (LC/MS) method to detect its presence was developed. Our approach is based on accurate mass measurements using a hybrid quadrupole-orbital trap mass spectrometer that was used to measure diltiazem and its metabolites in fish tissue. METHODS: Blood plasma, muscle, liver, and kidney tissues of rainbow trout (Oncorhynchus mykiss), exposed for 42 days to 30 µg L(-1) diltiazem, were used for the method development. No metabolite standards were required to identify the diltiazem biotransformation products in the fish tissue. RESULTS: Overall, 17 phase I diltiazem metabolites (including isomeric forms) were detected and tentatively identified using the MassFrontier spectral interpretation software. A semi-quantitative approach was used for organ-dependent comparison of the metabolite concentrations. CONCLUSIONS: These data increase our understanding about diltiazem and its metabolites in aquatic organisms, such as fish. These encompass desmethylation, desacetylation and hydroxylation as well as their combinations. This study represents the first report of the complex diltiazem phase I metabolic pathways in fish.

Perfluoroalkyl substances in aquatic environment-comparison of fish and passive sampling approaches.

The concentrations of seven perfluoroalkyl substances (PFASs) were investigated in 36 European chub (Squalius cephalus) individuals from six localities in the Czech Republic. Chub muscle and liver tissue were analysed at all sampling sites. In addition, analyses of 16 target PFASs were performed in Polar Organic Chemical Integrative Samplers (POCISs) deployed in the water at the same sampling sites. We evaluated the possibility of using passive samplers as a standardized method for monitoring PFAS contamination in aquatic environments and the mutual relationships between determined concentrations. Only perfluorooctane sulphonate was above the LOQ in fish muscle samples and 52% of the analysed fish individuals exceeded the Environmental Quality Standard for water biota. Fish muscle concentration is also particularly important for risk assessment of fish consumers. The comparison of fish tissue results with published data showed the similarity of the Czech results with those found in Germany and France. However, fish liver analysis and the passive sampling approach resulted in different fish exposure scenarios. The total concentration of PFASs in fish liver tissue was strongly correlated with POCIS data, but pollutant patterns differed between these two matrices. The differences could be attributed to the metabolic activity of the living organism. In addition to providing a different view regarding the real PFAS cocktail to which the fish are exposed, POCISs fulfil the Three Rs strategy (replacement, reduction, and refinement) in animal testing.

Contamination of fish in important fishing grounds of the Czech Republic.

The aim of this study was to compare the contamination levels of certain important fishing grounds in the Czech Republic and to assess the health risk of consuming the fish from these localities. The assessment was performed from 2006 to 2010 in 27 fishing grounds. Within this project, 707 fish from 14 different species were sampled. The concentration of selected toxic metals (Hg, Pb, Cd) and persistent organic pollutants (POPs), such as non-dioxin-like polychlorinated biphenyls (NDL-PCBs), hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) and its metabolites (o,p´-DDE; p,p´-DDE; o,p´-DDD; p,p´-DDD; o,p´-DDT; p,p´-DDT) and hexachlorobenzene (HCB), were analysed in the muscle tissue of the sampled fish. Atomic absorption spectrometry (AAS) was used for the analysis of toxic metals. All of the POPs were analysed using gas chromatography with an electron capture detector (GC/ECD). Common bream (Abramis brama) was chosen as a reference fish species for the comparison of fishing grounds. Mercury was found as a major pollutant in fish flesh at all of the sampling sites. Concentrations in excess of the maximum level (ML) of mercury in the muscle tissue of fish (0.5 mg kg(-1)) were registered in 32 samples. Concentrations of other monitored toxic metals in fish muscle were low, typically below the limit of quantification (LOQ). From the tested POPs, DDTs and NDL-PCBs were found as major pollutants. ML for NDL-PCBs (ICES-6) in muscle tissue of fish (0.125 mg kg(-1)) was exceeded in 7 samples. In case of tested pesticides, concentrations in excess of the MRL were not registered.

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.

Differential effects of antidepressant sertraline in glochidia-fish interactions involving drug transfer from parasite to host.

This study examined the impact of sertraline, an antidepressant common in treated wastewater, on the host-parasite dynamics between parasitic freshwater mussel (Unio tumidus, Unionidae) larvae (glochidia) and their host fish (Squalius cephalus, Cyprinidae). Employing a full-factorial design, both fish and glochidia were subjected to sertraline at the combinations of 0 µg L-1 (control), 0.2 µg L-1 (environmentally relevant concentration), and 4 µg L-1 (elevated concentration, short-term exposure of the parasite). The results showed that long-term host exposure (involving intensive sertraline accumulation in the fish brain) marginally increased subsequent glochidia attachment success by 2 %, while parasite exposure at the same environmentally relevant concentrations had no detectable effect. There was also no effect of exposure of glochidia to 0.2 µg L-1 of sertraline on their viability and encapsulation success during the initial parasitic stage. However, a significant alteration in attachment behavior, marked by a 3.3 % increase in attachment success and changes in the glochidia spatial distribution on the host body, was noted after 24 h of glochidia exposure to 4 µg L-1 of sertraline. Importantly, this study provides the first evidence of sertraline transfer from exposed glochidia to nonexposed host fish, as indicated by elevated levels of sertraline (12.8 ng g-1) in the brain tissue of nonexposed hosts. These findings highlight the subtle yet significant effects of pharmaceutical pollutants on freshwater ecosystems but also underscore the importance of understanding the unexpected dynamics of such contamination to predict and address future ecological changes.

Organic UV filters: Occurrence, risks and (anti-)progestogenic activities in samples from the Czech aquatic environment and their bioaccumulation in fish.

The occurrence, environmental risks and contribution of organic UV filters to detected (anti-)progestogenic activities were examined in samples of wastewater treatment plant influents and effluents, various surface waters and fish from the Czech Republic. Of the 20 targeted UV filters, 15 were detected in the WWTP influent samples, 11 in the effluents, and 13 in the surface water samples. Benzophenone-3, benzophenone-4, and phenyl benzimidazole sulfonic acid (PBSA) were found in all water samples. Octocrylene, UV-327 and 4-methylbenzylidene camphor exceeded the risk quotient of 1 at some sites. In the anti-progestogenic CALUX assay, 10 out of the 20 targeted UV filters were active. Anti-progestogenic activities reaching up to 7.7 ng/L, 3.8 ng/L, and 4.5 ng/L mifepristone equivalents were detected in influents, effluents, and surface waters, respectively. UV filters were responsible for up to 37 % of anti-progestogenic activities in influents. Anti-progestogenic activities were also measured in fish tissues from the control pond and Podrouzek (pond with the highest number of detected UV filters) and ranged from 2.2 to 9.5 and 1.9 to 8.6 ng/g dw mifepristone equivalents, respectively. However, only benzophenone was found in fish, but it does not display anti-progestogenic activity and thus could not explain the observed activities.

Combined effects of climate warming and pharmaceuticals on a tri-trophic freshwater food web.

Multiple anthropogenic stressors influence the functioning of lakes and ponds, but their combined effects are often little understood. We conducted two mesocosm experiments to evaluate the effects of warming (+4 °C above ambient temperature) and environmentally relevant concentrations of a mixture of commonly used pharmaceuticals (cardiovascular, psychoactive, antihistamines, antibiotics) on tri-trophic food webs representative of communities in ponds and other small standing waters. Communities were constituted of phyto- and zooplankton and macroinvertebrates (molluscs and insects) including benthic detritivores, grazers, omnivorous scrapers, omnivorous piercers, water column predators, benthic predators, and phytophilous predators. We quantified the main and interactive effects of warming and pharmaceuticals on each trophic level in the pelagic community and attributed them to the direct effects of both stressors and the indirect effects arising through biotic interactions. Warming and pharmaceuticals had stronger effects in the summer experiment, altering zooplankton community composition and causing delayed or accelerated emergence of top insect predators (odonates). In the summer experiment, both stressors and top predators reduced the biomass of filter-feeding zooplankton (cladocerans), while warming and pharmaceuticals had opposite effects on phytoplankton. In the winter experiment, the effects were much weaker and were limited to a positive effect of warming on phytoplankton biomass. Overall, we show that pharmaceuticals can exacerbate the effects of climate warming in freshwater ecosystems, especially during the warm season. Our results demonstrate the utility of community-level studies across seasons for risk assessment of multiple emerging stressors in freshwater ecosystems.

Presence of UV filters in surface water and the effects of phenylbenzimidazole sulfonic acid on rainbow trout (Oncorhynchus mykiss) following a chronic toxicity test.

UV filters belong to a group of compounds that are used by humans and are present in municipal waste-waters, effluents from sewage treatment plants and surface waters. Current information regarding UV filters and their effects on fish is limited. In this study, the occurrence of three commonly used UV filters - 2-phenylbenzimidazole-5-sulfonic acid (PBSA), 2-hydroxy-4-methoxybenzophenone (benzophenone-3, BP-3) and 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid (benzophenone-4, BP-4) - in South Bohemia (Czech Republic) surface waters is presented. PBSA concentrations (up to 13µgL(-1)) were significantly greater than BP-3 or BP-4 concentrations (up to 620 and 390ngL(-1), respectively). On the basis of these results, PBSA was selected for use in a toxicity test utilizing the common model organism rainbow trout (Oncorhynchus mykiss). Fish were exposed to three concentrations of PBSA (1, 10 and 1000µgL(-1)) for 21 and 42 days. The PBSA concentrations in the fish plasma, liver and kidneys were elevated after 21 and 42 days of exposure. PBSA increased activity of certain P450 cytochromes. Exposure to PBSA also changed various biochemical parameters and enzyme activities in the fish plasma. However, no pathological changes were obvious in the liver or gonads.

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.

Response of Parasite Community Composition to Aquatic Pollution in Common Carp (Cyprinus carpio L.): A Semi-Experimental Study.

The response of parasite communities to aquatic contamination has been shown to vary with both type of pollutant and parasite lifestyle. In this semi-experimental study, we examined uptake of pharmaceutical compounds in common carp (Cyprinus carpio L.) restocked from a control pond to a treatment pond fed with organic pollution from a sewage treatment plant and assessed changes in parasite community composition and fish biometric parameters. The parasite community of restocked fish changed over the six-month exposure period, and the composition of pharmaceutical compounds in the liver and brain was almost the same as that in fish living in the treatment pond their whole life. While fish size and weight were significantly higher in both treatment groups compared to the control, condition indices, including condition factor, hepatosomatic index, and splenosomatic index, were significantly higher in control fish. Parasite diversity and species richness decreased at the polluted site, alongside a significant increase in the abundance of a single parasite species, Gyrodactylus sprostonae. Oviparous monogeneans of the Dactylogyridae and Diplozoidae families and parasitic crustaceans responded to pollution with a significant decrease in abundance, the reduction in numbers most likely related to the sensitivity of their free-living stages to pollution.