Assessment of typical pollutants in waterborne by combining active biomonitoring and integrated biomarkers response

Planktonic communities as indicators of water quality in a tropical reservoir

Surface water bodies have been significantly altered by various human activities in the watersheds. Assessing these ecosystems is crucial for maintaining an ecological balance and protecting public health. This study aimed to analyse the water quality of a tropical public supply reservoir by evaluating the dynamics of planktonic communities. A total of 69 water quality parameters, in addition to phytoplankton and zooplankton biomonitoring data, were analyzed between 1989 and 2020. Preliminary and descriptive statistical analysis, trophic state index, Shannon-Wiener diversity index, statistical tests, and multivariate statistics analysis were applied. The results showed a change in the composition of the planktonic communities over time, with a greater abundance of cyanobacteria and an increase in the density of the Crustacea class in the final years of monitoring, indicating a more degraded environment. There was a reduction in the diversity of phytoplankton species. However, the concentrations of physical and chemical parameters remained low over the years, and oligotrophic conditions were prevalent in the reservoir. Therefore, the analysis of bioindicators provided information that was not observed when the physical and chemical parameters of water quality were analyzed. Possibly due to environmental variables not considered in this study, or due to the cumulative or synergistic effects caused by changes in the environment. It is evident that integrating bioassessment into the monitoring of water bodies is essential for a comprehensive ecological classification and for maintaining the integrity of the ecosystem.

Selenium toxicity and bioaccumulation in selenium-enriched fly (Chrysomya megacephala) maggots

Selenium (Se) is an essential trace element for human health, and as a potential animal feed, the Chrysomya megacephala (Fabricius) fly is rich in protein and fat. By using different concentrations of sodium selenite (0, 30, 50, 70 mg kg^-1), the possibility of biological Se enrichment in C. megacephala (Fabricius) maggots (CMMs) was investigated. The accumulation, Se speciation, enzymatic activity, and concentrations of copper (Cu), zinc (Zn), chromium (Cr), and cadmium (Cd) in the maggots were also determined. Transcriptomics was also used to investigate the mechanism of the Se response to CMM genes. The results showed that the CMMs had a survival rate of > 80% at Se exposure concentrations ranging from 0 to 100 mg kg^-1. The optimal concentration of sodium selenite for CMM growth was 50 mg kg^-1, and the weight, protein content, and total Se accumulation of the larvae (10.8 g, 53.5%, and 72.6 ± 3.36 mg kg^-1 (DW), respectively) were considerably higher than the control and other exposure doses (p < 0.05). In addition, Se improved the ability of maggots to absorb Cu and Zn, decreased malondialdehyde (MDA) and lipid peroxidation, but improved the antioxidant activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). Furthermore, Se negatively affected the absorption of Cd and Cr. According to the transcriptomic findings, Se supplementation can boost protein synthesis and control both antioxidant and non-antioxidant enzyme activity in CMMs. Therefore, our findings showed that Se-enriched CMMs may counteract the toxicity of Cd and Cr, and Se is an effective supplement for improving the consumption safety of cultured animals fed containing CMMs.

Field validated biomarker (ValidBIO) based assessment of impacts of various pollutants in water

The sensitivity of fish towards pollutants serves as an excellent tool for the analysis of water pollution. The effluents generated from various anthropogenic activities may contain heavy metals, pesticides, microplastics, and persistent organic pollutants (POPs) and ultimately find its way to aquatic environment. The enzymatic activities of fish collected from water bodies near major cities, oil spillage sites, agricultural land, and intensively industrialized areas have been reported to be significantly impacted in various field studies. These significant alterations in enzymatic activities act as a biomarker for monitoring purposes. The use of biomarkers not only helps in the identification of known and unknown pollutants and their detrimental health impacts, but also identifies the interaction between pollutants and organisms. The conventional method majorly used is physicochemical analysis, which is recognized as the backbone of the system for monitoring water quality. In physicochemical monitoring, major problems exist in assessing or predicting biological effects from chemical or physical data. Xenobiotic-induced enzymatic changes in fish may serve as an intuitive and efficient biomarker for determining contaminants in water bodies. Therefore, field validated biomarker (ValidBIO) approach needs to be integrated in water quality monitoring program for environmental health risk assessment of aquatic life impacted due to various point and non-point sources of water pollution.

Environmentally relevant lead (Pb) water concentration induce toxicity in zebrafish (Danio rerio) larvae

Early developmental stages of aquatic organisms including fish are inherently vulnerable to lead (Pb) and other water metal contaminants. However, reports on the deleterious effects of environmentally relevant Pb levels are limited. To this end, we exposed 2.5 h post fertilization (hpf) old zebrafish (Danio rerio) embryos to a range of Pb concentrations encompassing environmentally relevant levels (1, 10, 25, 50 and 100 μg/L Pb) until 96 hpf. Exposure negatively impacted the development and survival of zebrafish embryos by inducing embryo coagulation related mortalities in a concentration-dependent manner. At 24 hpf, the highest level of exposure (100 μg/L Pb) had impaired embryo activity characterized by reduced burst activity and the number of movements per minute made by embryos. At 72 hpf, newly hatched larvae exhibited adverse cardiovascular effects (100 μg/L Pb group) and neuromuscular effects (50 and 100 μg/L Pb groups). The antioxidant system dysregulation evidenced by downregulation of catalase, and upregulation of mRNA expression of glutathione S-transferase and cytochrome oxidase subunit I were observed. The pro-apoptotic tumour protein P53 (TP53) and the anti-apoptotic B cell lymphoma -2 (Bcl-2) mRNA expression levels were also affected. The former was downregulated across exposed groups and the latter was upregulated and downregulated in the groups with Pb concentrations less than 50 μg/L Pb and downregulated in 50 μg/L Pb, respectively. These findings suggest that Pb within environmentally relevant levels may be deleterious to developing zebrafish.

Molecular Methods as Potential Tools in Ecohydrological Studies on Emerging Contaminants in Freshwater Ecosystems

Contaminants of emerging concern (CECs) present a threat to the functioning of freshwater ecosystems. Their spread in the environment can affect both plant and animal health. Ecohydrology serves as a solution for assessment approaches (i.e., threat identification, ecotoxicological assessment, and cause–effect relationship analysis) and solution approaches (i.e., the elaboration of nature-based solutions: NBSs), mitigating the toxic effect of CECs. However, the wide array of potential molecular analyses are not fully exploited in ecohydrological research. Although the number of publications considering the application of molecular tools in freshwater studies has been steadily growing, no paper has reviewed the most prominent studies on the potential use of molecular technologies in ecohydrology. Therefore, the present article examines the role of molecular methods and novel omics technologies as essential tools in the ecohydrological approach to CECs management in freshwater ecosystems. It considers DNA, RNA and protein-level analyses intended to provide an overall view on the response of organisms to stress factors. This is compliant with the principles of ecohydrology, which emphasize the importance of multiple indicator measurements and correlation analysis in order to determine the effects of contaminants, their interaction with other environmental factors and their removal using NBS in freshwater ecosystems.

Single and combined effects of carbamazepine and copper on nervous and antioxidant systems of zebrafish (Danio rerio)

Various pollutants co-exist in the aquatic environment such as carbamazepine (CBZ) and copper (Cu), which can cause complex effects on inhabiting organisms. The toxic impacts of the single substance have been studied extensively. However, the studies about their combined adverse impacts are not enough. In the present study, zebrafish were exposed to environmental relevant concentrations of CBZ (1, 10, and 100 μg/L), Cu (0.5, 5, and 10 μg/L) and the mixtures (1 μg/L CBZ + 0.5 μg/L Cu, 10 μg/L CBZ + 5 μg/L Cu, 100 μg/L CBZ + 10 μg/L Cu) for 45 days, the effects on nervous and antioxidant systems of zebrafish were investigated. The results demonstrated that, in comparison with single exposure group, the combined presence of CBZ and Cu exacerbated the effect of antioxidant system (the ability of inhibition of hydroxyl radicals (IHR), superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST)) but not nervous system (Acetylcholinesterase [AChE]). The qPCR results supported the changes of corresponding enzymes activities. Hepatic histopathological analysis verified the results of biomarkers. Our work illustrated that the toxicity of mixed pollutants is very complicated, which cannot simply be inferred from the toxicity of single pollutant, and calls for more co-exposure experiments to better understanding of the co-effects of pollutants on aquatic organisms.

In Situ Assessment of Donghu Lake China Using Rare Minnow (Gobiocypris rarus)

In this work, rare minnow (Gobiocypris rarus) was applied as a sentinel organism and set in cages at control and test sampling sites in Donghu Lake for 4 weeks in March, June, September, and December 2016 to assess the biological toxicity of in situ water. Sampling for active biomonitoring and physicochemical variables was performed weekly. The control was obtained from the outdoor pool of the Institute of Hydrobiology, China. Superoxide dismutase, lipoperoxidation, metallothioneins, acetylcholinesterase activity, and Vtg mRNA expression were determined as biomarkers during the field exposure period. Survival and growth also were monitored to evaluate the overall physiological condition of the fish. The seasonal changes of organic pollutants and trace metals (As, Hg, Cr, Cu, Zn, Cd, Pb) in surface water were determined. The integrated biomarker response (IBR) index was applied to summarize biomarker responses and correlate stress levels with concentrations of organic pollutants and trace metals in the surface water. Results indicated that complex pollution by persistent organic pollutants and heavy metals was present in Donghu Lake and that the in situ exposed organisms were stressed. Moreover, the complex pollution of Donghu Lake in summer and autumn was more serious than that in spring and winter. Active biomonitoring combined with IBR analysis enabled good discrimination among different exposure seasons. The proposed protocol with caged rare minnow revealed marked biological effects caused by the investigated Lake and a useful approach that can easily be extended to monitor water pollution.

The dynamics of the pharmaceutical and personal care product interactive capacity under the effect of artificial enrichment of soil with heavy metals and of wastewater reuse

A greenhouse experiment was conducted, using a randomized block design, including twelve heavy metal (Mn, Zn, Cu, Cd, Co, Cr, Ni, Pb) mixture treatments, with each metal participating in the treatment with 0, 2, 4, 6, 8, 10, and 12 mg/kg, respectively. Common beet (Beta vulgaris L.) was chosen as test plant. The plants were irrigated with treated municipal wastewater taken from the Wastewater Treatment Plant of the town of Amaliada, N.W., Peloponnese, Greece. The experiment aimed at studying the interactions between heavy metals and macro-microelements, and pharmaceuticals and personal care products (PPCPs). The basic scope was to shed some light on the potential environmental implications, of these interactions on the soil PPCPs for a more effective monitoring of these emerging contaminants in the plants and soil continuum. It was found that the PPCPs have a very high potential interactive capacity, having interacted with all the studied metals, and metalloids, as well as with plant macro elements (P, and K). The uptake of PPCPs by plants was statistically significantly related with their respective content in the soil. The general inference is that the interactive relations between heavy metals, macro-, microelements, and emerging contaminants, being mainly antagonistic, which contribute to the decrease the uptake of soil PPCPs.

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.

mRNA expression of antioxidant and biotransformation enzymes in zebrafish (Danio rerio) embryos after exposure to the tricyclic antidepressant amitriptyline

Now-a-days, the occurrence of antidepressant residues in surface waters has become a major concern. Amitriptyline (AMI) has been described to treat depression and other disorders for decades. However, little is known about its effect on non-target organisms. The aim of this study was to assess the potential impact of AMI on the mRNA expression of antioxidant and detoxification enzymes during the early embryonic development of zebrafish (Danio rerio). Fertilized D. rerio embryos were exposed to AMI at concentrations of 300 ng/L and 30 μg/L and sampled 24, 48, 96, and 144 h post fertilization (hpf) to assess the mRNA expressions of cytochrome P450 1A1, glutathione-S-transferase, glutathione peroxidase, superoxide dismutase, and catalase. The time courses of the mRNA expressions of antioxidant and detoxification enzymes revealed characteristic changes during embryonic development causing generally transient changes post hatching; however, AMI did not cause any significant impact except in the case of CAT after 144 h, which was significantly upregulated by the AMI concentration of 30 μg/L. The results suggest that the antidepressant AMI causes only moderate to minor impacts on antioxidant and detoxification enzymes during early embryonic development of the non-target organism D. rerio and that CAT is the only biomarker affected by AMI.

Histological and Genotoxic Biomarkers in Prochilodus lacustris (Pisces, Prochilodontidae) for Environmental Assessment in a Protected Area in the Northeast of Brazil

The quality of aquatic environments all around the world is being altered by different human activities that represent direct threat to the ecological system and the aquatic biota. This study aimed to evaluate the occurrence of histological and genotoxic alterations in Prochilodus lacustris as indicators of anthropic impacts in a lacustrine environment in northeast Brazil. The histological alterations were evaluated using the histological alteration index, and the genotoxic alterations were detected using the micronuclei test, at three sampling stations (S1, S2 and S3). The gills presented lesions with three stages of severity, with mild lesions more frequent in the specimens collected at station S1. Mild hepatic tissue lesions were the most frequent type in both areas. Micronucleus analysis showed that station S3 was the most affected. The biological responses observed indicated that the fish are under influence of environmental changes. It is important to highlight that the organisms collected at station S3 had a more compromised health status.

Biomarker response, health indicators, and intestinal microbiome composition in wild brown trout (Salmo trutta m. fario L.) exposed to a sewage treatment plant effluent-dominated stream

Concerns about the effect of sewage treatment plant (STP) effluent on the health of freshwater ecosystems have increased. In this study, a unique approach was designed to show the effect of an STP effluent-dominated stream on native wild brown trout (Salmo trutta L.) exposed under fully natural conditions. Zivny stream is located in South Bohemia, Czech Republic. The downstream site of Zivny stream is an STP-affected site, which receives 25% of its water from Prachatice STP effluent. Upstream, however, is a minimally polluted water site and it is considered to be the control site. Native fish were collected from the upstream site, tagged, and distributed to both upstream and downstream sites. After 30, 90, and 180days, fish were recaptured from both sites to determine whether the downstream site of the Zivny stream is associated with the effects of environmental pollution. Several biomarkers indicating the oxidative stress and antioxidant enzyme activities, cytochrome P450 activity, xenoestrogenic effects, bacterial composition, and lipid composition were investigated. Additionally, polar chemical contaminants (pharmaceuticals and personal care products (PPCPs)) were quantified using polar organic chemical integrative samplers (POCIS). Fifty-three PPCPs were detected in the downstream site; 36 of those were constantly present during the 180-day investigation period. Elevated hepatic 7-benzyloxy-4-trifluoromethylcoumarin-O-debenzyloxylase (BFCOD) (after 90days) and blood plasma vitellogenin concentrations in males were detected in fish downstream of the STP effluent during all sampling events. An increase in the fishes' total fat content was also observed, but with low levels of ω-3 fatty acid in muscle tissue. Two bacterial taxa related to activated sludge were found in the intestines of fish from downstream. Our results show that Prachatice STP is a major source of PPCPs in the Zivny stream, which has biological consequences on fish physiology.

Diffuse sources of contamination in freshwater fish: Detecting effects through active biomonitoring and multi-biomarker approaches

Aquatic organisms are usually exposed to a mixture of xenobiotics that may exert a large effect even in low concentrations, and when information is obtained exclusively from chemical analyses the prediction of the deleterious effects is potentially hindered. Therefore, the application of complementary monitoring methods is a priority. Here, in addition to chemical analyses, an active biomonitoring study using multiple biomarker responses in Nile tilapia Oreochromis niloticus was conducted to assess the effects of a contamination gradient along four reservoirs in Iguaçu River. Chemical analysis in the muscle showed high levels of metals in fish from the reservoir closest to an industrialized and environmentally degraded area, however fish exposed to all studied reservoirs showed hepatic alterations (necrosis and inflammatory processes). Also, significant variations of biochemical biomarkers were observed with no clear indication of contamination gradient, since an indicative of higher impact was found in an intermediary reservoir, including high concentrations of biliary polycyclic aromatic hydrocarbons (PAHs). However, nuclear morphological alterations (NMA) were less frequent at the same reservoir. Thus, the multi-biomarker approach allied to active biomonitoring is a practical and important tool to assess deleterious effects of contamination in freshwater, providing data for monitoring and conservation protocols.

Preparation of pompon-like ZnO-PANI heterostructure and its applications for the treatment of typical water pollutants under visible light

Until now, the treatment of multiple water pollutants by using one simple material has still been a challenge. Pompon-like ZnO-Polyaniline heterostructures with different content of Polyaniline as out-layer were synthesized by hydrothermal method and hybridization. Their several applications were subsequently investigated for water pollutants treatment including photo-degradation of organic pollutants, photo-induced adsorption of heavy metal ions (Hg(II), Cr(VI)) and inactivation of Pathogenic bacteria (E. coli bacteria and staphylococcus aureus) under visible light. The results indicate that the aforementioned pollutants can be effectively removed by Pompon-like ZnO-Polyaniline heterostructure. The enhanced photochemical performance is attributed to: (1) the improved monodispersity and relative large specific surface area of pompon-like ZnO-PANI enhance the production of photo-induced OH and O₂^-; (2) the high separation efficiency of photo-generated electron-hole pairs, which comes from the synergistic effect of P-N type heterojunction.

Effects of pentachlorophenol on the quail (Coturnix japonica) liver detoxification pathway

Pentachlorophenol (PCP), an extensively used pesticide and biocide, is of critical environmental concern due to its toxicity and recalcitrance to degradation. In this study, the effect of PCP on induction of transcription factors, cytochrome P450 (CYP450) genes, and the antioxidative enzyme system were investigated in the quail liver. A total of 60 (4- to 6-week-old) male quails (Coturnix japonica) were administered 0, 0.05, 0.5, and 5 mg/kg/d PCP orally for 42 d. Following exposure, both absolute and relative liver weights were significantly lower than those of the control. Using gas chromatography-mass spectrometry, PCP accumulation was, from highest to lowest, kidney > liver > muscle for all exposure groups. The expressions of CYP1A5, CYP1B1, CYP2C18, nuclear translocator 1 (ARNT1), and aryl hydrocarbon receptor 1 (AHR1) were induced after PCP treatment, and increases were found in the activities of hepatic superoxide dismutase (SOD) and catalase (CAT), and the content of hepatic malondialdehyde (MDA). In addition, exposure to PCP induced an increase in liver 8-hydroxydeoxyguanosine (8-OHdG) and significantly elevated ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and 7-ethoxycoumarin-O-deethylase (ECOD) activity, but decreased that of glutathione peroxidase (GSH-Px), benzyloxyresorufin O-debenzylase (BROD), pentoxyresorufin O-depentylase (PROD), and erythromycin N-demethylase (END). No significant responses were observed for benzyloxy-trifluoromethyl-coumarin (BFC). The protein level of liver nuclear factor κB (NF-κB) was higher, whereas that of nuclear factor E2-related factor 2 (Nrf2) was lower for exposed quail. These results suggest that PCP affects quail oxidative stress by modulating CYP450 enzymes and nuclear transcription factors.

Simultaneous removal of Cr(VI) and 4-chlorophenol through photocatalysis by a novel anatase/titanate nanosheet composite: Synergetic promotion effect and autosynchronous doping

Clean-up of wastewaters with coexisting heavy metals and organic contaminants is a huge issue worldwide. In this study, a novel anatase/titanate nanosheet composite material (labeled as TNS) synthesized through a one-step hydrothermal reaction was demonstrated to achieve the goal of simultaneous removal of Cr(VI) and 4-cholophenol (4-CP) from water. TEM and XRD analyses indicated the TNS was a nano-composite of anatase and titanate, with anatase acting as the primary photocatalysis center and titanate as the main adsorption site. Enhanced photocatalytic removal of co-existent Cr(VI) and 4-CP was observed in binary systems, with apparent rate constants (k1) for photocatalytic reactions of Cr(VI) and 4-CP about 3.1 and 2.6 times of that for single systems. In addition, over 99% of Cr(VI) and 4-CP was removed within 120min through photocatalysis by TNS at pH 7 in the binary system. Mechanisms for enhanced photocatalytic efficiency in the binary system are identified as: (1) a synergetic effect on the photo-reduction of Cr(VI) and photo-oxidation of 4-CP due to efficient separation of electron-hole pairs, and (2) autosynchronous doping because of reduced Cr(III) adsorption onto TNS. Furthermore, TNS could be efficiently reused after a simple acid-base treatment.

Evaluation of the multiple biomarkers on identification of the vulnerable coastal pollution hotspots

This paper presents multiple biomarkers on metal accumulation and its impacts along the Chennai to Puducherry, southeast coast of India using bivalves as bioindicators. In this regard, water samples and Perna viridis were collected from three stations and the accumulation of metals and its biological impacts were assessed. Among the three sampling stations, the maximum accumulation was noticed in Ennore (S1) than the Puducherry (S3) followed by Kovalam (S2). Mean accumulation pattern of metals in Perna viridis was found to be in the following order Zn > Cu > Ni > Cr > Pb > Cd, which were in close match with the metal concentration in seawater at respective site. The ambient metal concentration and behavior of multiple biomarkers were positively correlated indicating that the uptake of metals might induce biological changes, particularly in the internal organs, thus significantly affecting health of the aquatic organisms. P. viridis provides reliable information concerning the adverse effects and reflects the integrated effects of all contaminants. Thus, study confirmed that Ennore (S1) coast is highly vulnerable for significant pollution, in terms of metal toxicity in the study area. Overall investigation revealed that metal enrichment was observed close to the major urban areas in the S1 and S2 which were associated with industrialized areas. The assessment of multiple biomarkers on metal accumulation was the first step in determining the trophic transfer factors on marine foot web, which can be evaluated in the future based on this study.

The applied indicators of water quality may underestimate the risk of chemical exposure to human population in reservoirs utilized for human supply-Southern Brazil

The knowledge concerning associations between chronic chemical exposure and many disorders with complex etiology involving gene-environment interactions is increasing, and new methods must be developed to improve water quality monitoring. The complexity of chemical mixtures in polluted aquatic environments makes the evaluation of toxic potential in those sites difficult, but the use of biomarkers and bioindicators has been recognized as a reliable tool to assess risk of exposure to biota and also the human population. In order to evaluate the use of fish and biomarkers to assess toxic potential and bioavailability of chemicals in human-related hydric resources, an in situ experiment was accomplished in two water reservoirs designated for human supply, which were previously evaluated by the local environmental regulatory agency through a set of physical, chemical, and classical biological parameters. Molecular, biochemical, and morphological biomarkers were performed in caged Oreochromis niloticus kept for 6 months in the studied reservoirs to assess potentially useful biomarkers to evaluate the quality of water for human supply. Chemical analysis of toxic metals in liver and muscle and polycyclic aromatic hydrocarbons (PAHs) in bile was considered to assess the bioavailability of pollutants and highlight human activity impact. The reservoir previously classified by a governmental agency as less impacted presented more risk of exposure to biota. These results were supported by chemical analysis, vitellogenin expression, histopathological findings (gonads, liver, and gills), as well as indicators of neurotoxic effects and oxidative stress in liver. The inclusion of some biomarkers as parameters in regulatory monitoring programs in reservoirs designated for human supply is strongly suggested to evaluate the risks of exposure to the human population. Thus, a revision of the traditional biological and physicochemical analysis utilized to establish the conditions of water quality is necessary.

Presence of pharmaceuticals and heavy metals in the waters of a Mediterranean coastal wetland: Potential interactions and the influence of the environment

The occurrence of 17 relevant pharmaceuticals and 7 heavy metals in the waters of the Pego-Oliva Marsh Natural Park (Valencia Community, Spain) were monitored. Thirty four zones (including the lagoon and the most important irrigation channels), covering the main land uses and water sources, were selected for sampling. Thirty three of them were contaminated with at least one pharmaceutical. Ibuprofen and codeine were the pharmaceuticals more frequently detected, in concentrations between 4.8 and 1.2 ng/L and a maximum of 59 ng/L and 63 ng/L, respectively. Regarding metals, Zn showed values under the detection limit in all the samples, while Cd, Co, Cr, Cu, Ni and Pb were detected at concentrations lower than the WHO and EU maximum levels for drinking waters. Ni showed significant direct correlations with diazepam, norfloxacin, ofloxacin and fenofibrate, and inverse relationships with ibuprofen, at 99 and 95% of significance. Cu, Co and Cr also showed significant correlations with some of the pharmaceuticals. These interactions could favor the synergistic/antagonistic interactions among pharmaceuticals and metals in the marsh, which can affect its aquatic fauna and flora or even human health. The influences of the water sources, land uses and spatial distribution of both types of contaminants were also studied.

Effects of norfloxacin on hepatic genes expression of P450 isoforms (CYP1A and CYP3A), GST and P-glycoprotein (P-gp) in Swordtail fish (Xiphophorus Helleri)

The presence of antibiotics including norfloxacin in the aquatic environment may cause adverse effects in non-target organisms. But the toxic mechanisms of fluoroquinolone to fish species are still not completely elucidated. Thus, it is essential to investigate the response of fish to the exposure of fluoroquinolone at molecular or cellular level for better and earlier prediction of these environmental pollutants toxicity. The sub-chronic toxic effects of norfloxacin (NOR) on swordtail fish (Xiphophoru s helleri) were investigated by measuring mRNA expression of cytochrome P450 1A (CYP1A), cytochrome P450 3A (CYP3A), glutathione S-transferase (GST) and P-glycoprotein (P-gp) and their corresponding enzyme activities (including ethoxyresorufin O-deethylase, erythromycin N-demethylase and GST. Results showed that NOR significantly affected the expression of CYP1A, CYP3A, GST and P-gp genes in swordtails. The gene expressions were more responsive to NOR exposure than their corresponding enzyme activities. Moreover, sexual differences were found in gene expression and enzyme activities of swordtails exposed to NOR. Females displayed more dramatic changes than males. The study further demonstrated that the combined biochemical and molecular parameters were considered as useful biomarkers to improve our understanding of potential ecotoxicological risks of NOR exposure to aquatic organisms.

Effects of the non-steroidal anti-inflammatory drug(NSAID) naproxen on gene expression of antioxidant enzymes in zebrafish (Danio rerio)

The aim of this study was to investigate the effects of naproxen on the gene expression of antioxidant enzymes in adult zebrafish. Surprisingly, after 2 weeks exposure no significant effect on the mRNA expression of the target genes was found in the liver. However, mRNA levels of three genes were altered significantly in the intestine. The expression of Ucp-2 decreased at the environmental concentration of 1μg/L while mRNA expression of GST p2 increased at the concentration of 100μg/L. The mRNA level for the antioxidant enzyme CAT was up-regulated significantly at both the concentrations used. Exposure to naproxen caused only moderate effects on the expression of antioxidant genes in the intestine rather than in the liver, which demonstrates that the intestine is more sensitive to waterborne naproxen exposure than the liver. Interestingly, the adverse side effects of NSAIDs occur in the gastrointestinal tract of humans. To our knowledge, this is the first study that has focused on transcriptional effects of naproxen on zebrafish.

The influence of the occupational exposure to heavy metals and tobacco smoke on the selected oxidative stress markers in smelters

The aim of the study was to verify if there is any association between exposure to Cu, Zn, Cd, Pb, As and the formation of malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), advanced oxidation protein products (AOPP), and whether in this process cigarette smoking plays a role. The investigations were performed in the 352 smelters occupationally exposed to heavy metals and 73 persons of control group. Metals concentration was determined by atomic absorption spectrometry. MDA and AOPP concentrations were determined by spectrophotometric methods. The concentration of 8-OHdG was determined by ELISA method. It was demonstrated an increased Cu concentration in smoking smelters compared to non-smoking control group. It was noted no differences in Zn and Mg concentrations between the examined groups. Pb concentration was more than sixfold higher in the group of smoking smelters and about fivefold higher in the group of non-smoking smelters compared to the control groups (smokers and non-smokers). It was shown that Cd concentration in the blood was nearly fivefold higher in the smoking control group compared to the non-smoking control group and more than threefold higher in the group of smoking smelters compared to non-smoking. It was shown an increased As concentration (more than fourfold) and decreased Ca concentration in both groups of smelters compared to control groups. In groups of smelters (smokers and non-smokers), twofold higher MDA and AOPP concentrations, and AOPP/albumin index compared to control groups (smokers and non-smokers) were shown. Tobacco smoke is the major source of Cd in the blood of smelters. Occupational exposure causes accumulation of Pb in the blood. Occupational exposure to heavy metals causes raise of MDA concentration and causes greater increase in AOPP concentration than tobacco smoke.

Effect of acetaminophen exposure in Oncorhynchus mykiss gills and liver: detoxification mechanisms, oxidative defence system and peroxidative damage

The increasing presence of pharmaceutical drugs in nature is cause of concern due to the occurrence of oxidative stress in non-target species. Acetaminophen is widely used in human medicine as an analgesic and antipyretic drug, and it is one of the most sold non-prescription drugs. The present study aimed to assess the toxic effects of acetaminophen (APAP) in Oncorhynchus mykiss following acute and chronic exposures in realistic levels. In order to evaluate the APAP effects in the rainbow trout, gills and liver were analyzed with biochemical biomarkers, such as catalase (CAT), total and selenium-dependent glutathione peroxidase (GPx), glutathione reductase (GRed) and glutathione-S-transferases (GSTs) activity and also lipid peroxidation levels (TBARS). The results obtained in all tests indicate that a significant response of oxidative stress was established, along with the increase of APAP concentrations. The establishment of an oxidative stress scenario occurred with the involvement of all tested biomarkers, sustaining a generalized set of pro-oxidative effects elicited by APAP. Additionally, the occurrence of oxidative damage strongly suggests the impairment of the antioxidant defense mechanism of O. mykiss. It is important to note that the occurrence of oxidative deleterious effects and peroxidative damages occurred for concentrations similar to those already reported for several freshwater ecosystems. The importance of these assumptions is further discussed under the scope of ecological relevance of the assessment of effects caused by pharmaceuticals in non-target organisms.

Use of fish farms to assess river contamination: combining biomarker responses, active biomonitoring, and chemical analysis

Here we addressed the possible effects of trace levels of contaminants on fish by means of a combination of biomarker responses, active biomonitoring (ABM), and chemical analysis. In environmental studies, cytochromes P4501A (Cyp1A) and Cyp3A and related enzyme activities (7-ethoxyresorufin-O-deethylase, EROD, and benzyloxy-4-[trifluoromethyl]-coumarin-O-debenzyloxylase, BFCOD, respectively) are commonly used as biomarkers for evidencing exposure to a variety of contaminants. In a rainbow trout (Oncorhynchus mykiss) fish farm that is routinely sampled to obtain references regarding normal levels of such enzyme activities in freshwater fish, we observed a strong and punctual increase in these activities at the end of 2011. In order to shed light on the causes of this induction, we transferred some fish to a fish farm with controlled conditions and examined them using an active biomonitoring (ABM) approach. EROD activity showed a decrease of 80% from the original values after 7 days in the control farm, while BFCOD activity was also reduced after 15 days. Although not significant, a decrease in cyp1A and cyp3A mRNA levels was also observed. To determine the presence of pollutants, water and sediment samples from the river feeding the fish farm were analyzed by two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS). The screening study reflected a weak inflow of pollutants in the monitored area, which is located far from any industrial activity or densely populated cities. Trace levels of polyaromatic hydrocarbons (PAHs) and personal care products (the polycyclic musk fragrance HHCB, and triclosan) were detected in sediments, at concentrations ranging from 0.01 to 38 ng/g dry weight, and in water from 4 to 441 ng/L. The approach followed in this study proved useful as a biomonitoring technique for the early detection of trace contaminants.

Effect of atrazine and chlorpyrifos exposure on cytochrome P450 contents and enzyme activities in common carp gills

Chlorpyrifos (CPF) and atrazine (ATR) are the most widely used organophosphate insecticides and triazine herbicides, respectively, worldwide. This study aimed at investigating the effects of ATR, CPF and mixture on common carp gills following 40-d exposure and 40-d recovery experiments. Cytochrome P450 content, activities of aminopyrine N-demethylase (APND) and erythromycin N-demethylase (ERND) and the mRNA levels of the CYP1 family (CYP1A, CYP1B, and CYP1C) were determined. In total, 220 common carps were divided into eleven groups, and each group was treated with a specific concentration of ATR (4.28, 42.8 and 428 μg/L), CPF (1.16, 11.6 and 116 μg/L) or ATR-CPF mixture (1.13, 11.3 and 113 μg/L). The results showed that P450 content and activities of APND and ERND in fish exposed to ATR and mixture were significantly higher than those in the control group. After the 40-d recovery treatment (i.e., depuration), the P450 content and the activities of APND and ERND in fish decreased to the background levels. A similar tendency was also found in the mRNA levels of the CYP1 family (CYP1A, CYP1B, and CYP1C) in common carp gills. The CPF-treated fish showed no significant difference from the control groups, except for a significant CYP1C induction. These results indicated that CYP enzyme levels are induced by ATR but were only slightly affected by CPF in common carp gills. In addition, the ATR and CPF exposure showed an antagonistic effect on P450 enzymes in common carp gills.

Gill histopathological and oxidative stress evaluation in native fish captured in Portuguese northwestern rivers

The Northwestern Portuguese region is densely populated and highly industrialized, suffering from high anthropogenic pressure. To assess the biological effect of the several pollutants that are constantly released to the water, a biomarker-based biomonitoring is a promising approach that may provide early-warning signals of pollutants exposure. Fish gill is the first target of pollutants action, thus histopathological and biochemical changes may constitute potential biomarkers. To evaluate this hypothesis, three native fish species (barbel-Luciobarbus bocagei, chub-Squalius carolitertii and nase-Pseudochondrostoma sp.) were sampled in Northwestern Portuguese rivers, the gill histopathological changes were qualitative and quantitatively analyzed and the lipid peroxidation and glutathione-S-transferase activity were determined. A multivariate statistical analysis was performed to establish correlations between these biological responses, environmental variables and ecological status. The quantitative evaluation of the main histopathological changes and oxidative stress responses emphasize the differences, among species, in the responses to the presence of contaminants in water. Discriminant canonical analysis showed that filament epithelium proliferation, necrosis and GST activity were the main contributors to discriminate the ecological status classification. In addition, the results showed that a wide range of environmental factors are influencing fish physiology. In conclusion, the gill biological responses, although not reflecting specific contaminants, can be used as biomarkers of ecosystems perturbation.

Contamination by metals and pharmaceuticals in northern Taihu Lake (China) and its relation to integrated biomarker response in fish

Taihu Lake is the largest shallow freshwater lake in eastern China and is suffering not only from an increasingly serious threat of eutrophication but also potential ecological risk due to the input of emerging contaminants. Active biomonitoring was conducted in Taihu Lake using transplanted goldfish (Carassius auratus) to determine the contamination by pharmaceuticals and metals and to assess the potential ecological risk. A suite of biomarkers including acetylcholinesterase, ethoxyresorufin O-deethylase, glutathione S-transferase, glutathione peroxidase and superoxide dismutase activities in fish after 7, 14, 21 and 28 days of exposure in situ, as well as pharmaceuticals and metals in water, were determined during the field exposure period. The results indicate that pharmaceuticals exist mainly in Zhushan Bay and Meiliang Bay, while metals are present mainly in Gong Bay. An integrated biomarker response (IBR) was calculated and used to evaluate the ecological risk of the polluted area of Taihu Lake. It was found that Zhushan Bay might present higher risk to fish, followed by Meiliang Bay. IBR values were in good agreement with copper and caffeine concentrations.

Assessment of toxic effects of triclosan on the swordtail fish (Xiphophorus helleri) by a multi-biomarker approach

The toxic effects of triclosan (TCS) on the swordtail fish (Xiphophorus helleri) were assessed based on various biomarkers including enzymatic activities of ethoxyresorufin O-deethylase (EROD), erythromycin N-demethylase (ERND) and glutathione-s-transferase (GST) and mRNA expression levels of CYP1A, CYP3A, glutathione S-transferase (GST) and P-glycoprotein (P-gp). The acute toxicity test showed the LC(50) value of 1.47 mg L(-1) for TCS. The mRNA expressions of CYP1A, CYP3A, GST and P-gp showed dose-effect relationships in female swordtail fish when exposed to TCS, These mRNA expression levels were found more sensitive to TCS exposure than the enzymatic activities of EROD, ERND and GST do. In addition, the male fish displayed higher gene expression levels and more dramatic changes in enzyme activities than the females did. Our data further demonstrated that TCS was a typical inducer to Phase I and Phase II metabolism enzymes and genes, suggesting it is a potential ecotoxicological risk to aquatic ecosystems.

Gene expression patterns and stress response in marine copepods

Aquatic organisms are constantly exposed to both physical (e.g. temperature and salinity variations) and chemical (e.g. endocrine disruptor chemicals, heavy metals, hydrocarbons, diatom toxins, and other toxicants) stressors which they react to by activating a series of defense mechanisms. This paper reviews the literature on the defense systems, including detoxification enzymes and proteins (e.g. glutathione S-transferases, heat shock proteins, superoxide dismutase and catalase), studied in copepods at the molecular level. The data indicate high inter- and intra-species variability in copepod response, depending on the type of stressor tested, the concentration and exposure time, and the enzyme isoform studied. Ongoing -omics approaches will allow the identification of new genes which will give a more comprehensive overview of how copepods respond to specific stressors in laboratory and/or field conditions and the effects of these responses on higher trophic levels.