Induction of micronuclei and nuclear abnormalities in Oreochromis niloticus following exposure to petroleum refinery and chromium processing plant effluents

17β-Estradiol induces cyto-genotoxicity on blood cells of common carp (Cyprinus carpio)

17β-Estradiol, a natural hormone present at high concentrations in aquatic ecosystems, affects and modifies endocrine function in animals. In recent years research workers have expressed concern over its potential effects on aquatic organisms; however, little is known about its capacity to induce genetic damage or the pro-apoptotic effects of such damage on fish. Therefore, this study aimed to evaluate 17β-estradiol-induced cyto-genotoxicity in blood cells of the common carp Cyprinus carpio exposed to different concentrations (1 ng, 1 μg and 1 mg L^-1). Peripheral blood samples were collected and evaluated by comet assay, micronucleus test, determination of caspase-3 activity and TUNEL assay at 12, 24, 48, 72 and 96 h of exposure. Increases in frequency of micronuclei, TUNEL-positive cells and caspase-3 activity were observed, particularly at the highest concentration. In contrast, the comet assay detected significant increases at 24 and 96 h with the 1 μg and 1 ng L^-1 concentrations respectively. The set of assays used in the present study constitutes a reliable early warning biomarker for evaluating the toxicity induced by this type of emerging contaminants on aquatic species.

Cypermethrin: Oxidative stress and genotoxicity in retinal cells of the adult zebrafish

Cypermethrin (CM), widely used for control of indoor and field pests, is one of the most common contaminants in freshwater aquatic systems. We evaluated CM genotoxicity and the activities of superoxide dismutase (SOD) and catalase (CAT) in retinal cells of adult zebrafish. Histological and immunofluorescence techniques show the presence of apoptotic cells in the zebrafish retina after 9 d of treatment with 0.6 μg/L CM. Histone γ-H2AX, a marker of DNA damage, was detected in both outer and inner nuclear layers; caspase-3, an apoptotic marker, was detected in the outer nuclear layer. In the comet assay, the cells were sensitive to hydrogen peroxide-induced DNA damage, showing a dose-dependent response. We observed a positive comet assay response to CM that was dose- and time-dependent. Following exposure to CM, SOD and CAT enzyme activities, and sod and cat mRNA levels, increased. These results indicate that CM causes DNA damage and oxidative stress and can induce apoptosis in retinal cells.

Effects of triclosan on acute toxicity, genetic toxicity and oxidative stress in goldfish (Carassius auratus)

Triclosan (TCS) is used as an antimicrobial agent and has been widely dispersed and detected in the aquatic environment. However, it remains uncertain whether TCS is genotoxic or not. In this study, the acute toxicity of TCS in goldfish (Carassius auratus) was studied. Then, based on the results for acute toxicity, other goldfish were exposed to various concentrations of TCS (control, DMSO control, and 1/4, 1/2, and 1/8 LC₅₀) for 14 days, and the effects on genetic toxicity were evaluated using micronucleus (MN) and nuclear abnormalities (NA) frequencies in peripheral blood and the comet assay in the liver of the goldfish. In addition, malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), and total antioxidant capacity (T-AOC) in the liver were assayed to evaluate oxidative stress and the possible mechanism of genotoxicity. The 96 h median lethal concentration of TCS was 1111.9 µg/l. After 14 days of exposure, the MN and NA frequencies were significantly increased in peripheral blood of the TCS-treated groups compared with the solvent control, and the comet tail moment and MDA in the liver in the highest dose of TCS groups were also significantly high. Meanwhile, an evident change in GSH, CAT, and T-AOC of the liver was found as the TCS exposure concentration increased. The results showed that TCS caused oxidative stress and a genotoxic response in goldfish, suggesting that it presents a potential ecotoxicological risk to aquatic ecosystems.

Erythrocytes as a biological model for screening of xenobiotics toxicity

Erythrocytes are the main cells in circulation. They are devoid of internal membrane structures and easy to be isolated and handled providing a good model for different assays. Red blood cells (RBCs) plasma membrane is a multi-component structure that keeps the cell morphology, elasticity, flexibility and deformability. Alteration of membrane structure upon exposure to xenobiotics could induce various cellular abnormalities and releasing of intracellular components. Therefore the morphological changes and extracellular release of haemoglobin [hemolysis] and increased content of extracellular adenosine triphosphate (ATP) [as signs of membrane stability] could be used to evaluate the cytotoxic effects of various molecules. The nucleated RBCs from birds, fish and amphibians can be used to evaluate genotoxicity of different xenobiotics using comet, DNA fragmentation and micronucleus assays. The RBCs could undergo programmed cell death (eryptosis) in response to injury providing a useful model to analyze some mechanisms of toxicity that could be implicated in apoptosis of nucleated cells. Erythrocytes are vulnerable to peroxidation making it a good biological membrane model for analyzing the oxidative stress and lipid peroxidation of various xenobiotics. The RBCs contain a large number of enzymatic and non-enzymatic antioxidants. The changes of the RBCs antioxidant capacity could reflect the capability of xenobiotics to generate reactive oxygen species (ROS) resulting in oxidative damage of tissue. These criteria make RBCs a valuable in vitro model to evaluate the cytotoxicity of different natural or synthetic and organic or inorganic molecules by cellular damage measures.

Biomarkers and bioindicators of the environmental condition using a fish species (Pimelodus maculatus Lacepède, 1803) in a tropical reservoir in Southeastern Brazil

Abstract The Funil Reservoir receives a large amount of xenobiotics from the Paraíba do Sul River (PSR) from large number of industries and municipalities in the watershed. This study aimed to assess environmental quality along the longitudinal profile of the Paraíba do Sul River–Funil Reservoir system, by using biomarkers and bioindicators in a selected fish species. The raised hypothesis is that Funil Reservoir acts as a filter for the xenobiotics of the PSR waters, improving river water quality downstream the dam. Two biomarkers, the ethoxyresorufin–O–deethylase activity (EROD), measured as fluorimetricly in S9 hepatic fraction, and the micronuclei frequency (MN), observed in erythrocytes of the cytoplasm, and three bioindicators, the hepatosomatic index (HSI), gonadosomatic index (GSI) and condition factor (CF) were used in Pimelodus maculatus, a fish species widely distributed in the system. Four zones were searched through a longitudinal gradient: 1, river upstream from the reservoir; 2, upper reservoir; 3, lower reservoir; 4, river downstream of the reservoir. EROD activity and HSI and GSI had significant differences among the zones (P<0.05). The upper reservoir had the lowest EROD activity and HSI, whereas the river downstream of the reservoir had the highest EROD and lowest GSI. The river upstream from the reservoir showed the highest HSI and GSI. It is suggested that the lowest environmental condition occur at the river downstream of the reservoir, where it seems to occur more influence of xenobiotics, which could be associated with hydroelectric plant operation. The hypothesis that Funil reservoir acts as a filter decanting pollution from the Paraíba do Sul River waters was rejected. These results are novel information on this subject for a native fish species and could be useful for future comparisons with other environments.

Alterations in liver marker enzymes and recovery ability of cyprinids as indicators of aquatic pollution

Information on the detection of pesticides in fresh water Lakes of Kashmir (Dal and Mansbal) through GC-MS technique is scarce, and also the recovery in biochemical parameters (AST, ALT and ALP) of fish after transferring them to clean media has not been reported yet. The water samples were collected from three sites and analyzed for their pesticide profile by dispersive liquid-liquid micro extraction (DLLME) followed by GC-MS. Influence of pesticides on liver marker enzymes of Cyprinus carpio and Carassius carassius was also investigated. The results obtained showed the presence of three main pesticides viz. chlorpyrifros, dimethoate and dichlorvos in waters of Dal Lake whereas no pesticide was detected in waters of Mansbal. The higher values for AST, ALT and ALP activities and decrease in protein content were obtained in the samples from the Dal Lake compared with those from Mansbal Lake (p < 0.05). These data when compared with the values found in C. carpio and C. carassius from both the Dal Lake and Mansbal Lake kept under laboratory conditions after 15, 30, 45 and 60 days of maintenance in clean media found that during depuration, all the enzyme activities came down significantly (p < 0.05) indicating the compensatory response by the fish against the pesticide stress. Therefore, these parameters could be used as indicators of pesticide pollution in aquatic organisms and were recommended for environmental monitoring for investigating the mechanism involved in the recovery pattern.

A comparative approach using biomarkers in feral and caged Neotropical fish: Implications for biomonitoring freshwater ecosystems in agricultural areas

The aim of this study was to investigate the responses of biomarkers in feral and caged fish and the capacity of these biomarkers to discriminate contamination levels along a stream located in an agricultural area in Southern Brazil. Specimens of the Neotropical fish, Astyanax altiparanae, were confined for 168h in three lakes along the stream. Additionally, during the weeks of in situ exposure, wild specimens of this species were collected from the same sites. Biochemical biomarkers were analyzed, such as phase I biotransformation enzyme 7-ethoxyresorufin-O-deethylase (EROD) and phase II biotransformation enzyme glutathione S-transferase, and we also determined hepatic and branchial levels of non-protein thiols (NPSH), oxidative damage such as lipid peroxidation (LPO), and acetylcholinesterase (AChE) activity in muscle and brain. Genetic biomarkers such as DNA breaks (comet assay), frequency of micronuclei (MN) and erythrocytic nuclear abnormalities (ENA) were also examined. The results indicate that the most sensitive biomarkers for discriminating contamination levels are DNA breaks, LPO and AChE activity. Similar results were obtained for both caged and feral fish. The biomarkers that reflect the results of cumulative events, such as ENA, were more discriminative for chronically exposed specimens (feral fishes). Analyzing biomarkers using an integrated response index showed that both approaches (using feral and caged A. altiparanae) were effective for discriminating contamination levels along the stream, corroborating the results of chemical analyses for selected pesticides. Taken together, these results highlight the importance of biomarker selection and show that both approaches (caged and feral fish) are satisfactory for evaluating water quality in streams impacted by agricultural activities.

In vitro and in vivo investigation of the genotoxic potential of waters from rivers under the influence of a petroleum refinery (São Paulo State - Brazil)

In recent years concern about the chemical composition of wastewater generated by the oil refining industry has increased, even after its treatment. These wastewaters contain substances that can harm both the entire aquatic ecosystem and the health of any exposed organisms. The aim of this study was to evaluate the genotoxic and mutagenic potentials of the effluent generated by the largest Brazilian petroleum refinery, the effectiveness of the treatments used by the refinery, and whether its effluent can compromise the water quality of the river where it is discarded. Chromosomal aberration and micronucleus assays were performed in Allium cepa and micronucleus test in mammalian cell culture (CHO-K1). The samples were collected in three sites at the refinery: one site on the Jaguari River and two sites on the Atibaia Rivers (upstream and downstream of the discharged effluent), under three different climatic conditions. Tests with A. cepa showed increased frequencies of chromosomal aberrations and micronuclei in meristematic cells for the effluent after physico-chemical treatment, but the samples after treatment biological and stabilization pond presented none of these abnormalities. It was observed that the induced damage in the meristematic cells was not observed in the F₁ cells of A. cepa roots. The micronucleus test performed with mammalian cell culture also indicated that the effluent, after physico-chemical treatment, induced a significant increase in micronucleus frequencies. Plant and hamster cells exposed to the other samples collected inside the refinery and in the Jaguari and Atibaia Rivers did not present evidence of genotoxicity and mutagenicity in the tests performed. This study showed that the effluent treated carried out by the refinery (biological treatment followed by a stabilization pond) proved to be efficient for the removal of the toxic load still present after the physico-chemical treatment, since no change in the quality of the Atibaia River was observed. However, because this is an industry with a high production of effluent with toxic potential, its effluents must be constantly monitored, so that there is no compromise of the water quality of the receiving river.

Cyto-genotoxicity and oxidative stress in common carp (Cyprinus carpio) exposed to a mixture of ibuprofen and diclofenac

Thirty million people worldwide consume each day nonsteroidal anti-inflammatory drugs (NSAIDs), a heterogeneous group of pharmaceuticals used for its analgesic, antipyretic, and anti-inflammatory properties. Recent studies report high NSAID concentrations in wastewater treatment plant effluents, in surface, ground, and drinking water, and in sediments. NSAIDs are also known to induce toxicity on aquatic organisms. However, toxicity in natural ecosystems is not usually the result of exposure to a single substance but to a mixture of toxic agents, yet only a few studies have evaluated the toxicity of mixtures. The aim of this study was to evaluate the toxicity induced by diclofenac (DCF), ibuprofen (IBP), and their mixture on a species of commercial interest, the common carp Cyprinus carpio. The median lethal concentration of IBP and DCF was determined, and oxidative stress was evaluated using the following biomarkers: lipid peroxidation and activity of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. Cyto-genotoxicity was evaluated by micronucleus test, comet assay, and the specific activity of caspase-3. Results show that DCF, IBP, and a mixture of these pharmaceuticals induced free radical production, oxidative stress and cyto-genotoxicity in tissues of C. carpio. However, a greater effect was elicited by the mixture than by either pharmaceutical alone in some biomarkers evaluated, particularly in gill. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1637-1650, 2017.

Aneugenicity and clastogenicity in freshwater fish Oreochromis niloticus exposed to incipient safe concentration of tannery effluent

Conventional effluent bioassays mostly rely on overt responses or endpoints such as apical and Darwinian fitness. Beyond the empirical observation, laboratory toxicity testing needs to rely on effective detection of prognostic biomarkers such as genotoxicity. Indeed, characterization of tannery effluent requires slotting in of genotoxic responses in whole effluent toxicity testing procedures. Hence, the prime objective of the present experimental investigation is to apply the technique of biological assay as a tool of toxicity testing to evaluate the induction of micronuclei (MN) in peripheral erythrocytes, and exfoliated cells of gill and kidney of O.niloticus exposed to Maximum tolerable concentrations (MTCs) of composite Modjo tannery effluent (CMTE) and to compare the sensitivity of each cells origin to the induction of MN. After 72h of exposure, cellular aberrations were detected using MN and nuclear abnormality (NA) tests. The induction of MN was significantly higher in exposed groups (P<0.05) when compared to the control group; moreover the tissue specific MN response was in the order, gill cells>peripheral erythrocyte>kidney. Total NA was found to increase significantly (P<0.05), when compared to the non-exposed group. NA was also further ramified as blebbed (BL), bi-nucleated (BN), lobbed (LB) and notched (NT) abnormalities. The result of each endpoint measured has demonstrated that at a concentration of total chromium (0.1, 0.73 and 1.27mg/L), a perceptible amount cellular aberration was measured, further implicating somber treat of genotoxicity to fishes, if exposed to water contaminated with tannery effluent. This further highlight that conventional effluent monitoring alone cannot reveal the effects expressed at cellular and genetic levels further demanding the incorporation of effluent bioassays in risk assessment and risk management/abatement programs.

Micronuclei and other nuclear abnormalities on Caiman latirostris (Broad-snouted caiman) hatchlings after embryonic exposure to different pesticide formulations

This study aimed to evaluate the embryotoxicity and genotoxicity of pesticide commercial formulations widely used in soybean crops through the Micronucleus (MN) test and other Nuclear Abnormalities (NAs) in erythrocytes of broad-snouted caiman (Caiman latirostris), exposed by topical application through the eggshell. Embryos were exposed (during all incubation: 70 days approximately) to sub-lethal concentrations of two glyphosate formulations PanzerGold® (PANZ) and Roundup® Full II (RU) (500, 750, 1000µg/egg); to the endosulfan (END) formulation Galgofan® and the cypermethrin (CYP) formulation Atanor® (1, 10, 100, and 1000µg/ egg). Blood samples were taken at the moment of hatching from the spinal vein for the application of the MN test and analysis of other NAs in erythrocytes, as markers of genotoxicity. Results indicated a significant increase in the frequency of MN for PANZ1000, END 10, CYP 1 and CYP 100 (p<0.05), and in the frequency of other NAs including Buds: END 100, 1000 and CYP 10 (p<0.05), eccentric nuclei: END 1, 10, 1000, CYP 10, 100, 1000 (p<0.01) and END 100 (p<0.05), notched nuclei: END 1, 10 (p<0.01) and END 1000, CYP 10, 100,1000 (p<0.05), and total nuclear abnormalities: END 1, 10, 100, 1000, CYP 10, 100 and 1000 (p<0.01), and the positive control (PC) (p<0.05), compared with the negative control. It was demonstrated a concentration dependent-effect in MN frequency only for PANZ (R2=0.98; p<0.01). Our study demonstrated that commercial formulations of pesticides induced genotoxic effects on C. latirostris, and NAs are a good indicator of genotoxicity in this specie.

Geno- and cytotoxicity induced on Cyprinus carpio by aluminum, iron, mercury and mixture thereof

Metals such as Al, Fe and Hg are used in diverse anthropogenic activities. Their presence in water bodies is due mainly to domestic, agricultural and industrial wastewater discharges and constitutes a hazard for the organisms inhabiting these environments. The present study aimed to evaluate geno- and cytotoxicity induced by Al, Fe, Hg and the mixture of these metals on blood of the common carp Cyprinus carpio. Specimens were exposed to the permissible limits in water for human use and consumption according to the pertinent official Mexican norm [official Mexican norm NOM-127-SSA1-1994] Al (0.2mgL^-1), Fe (0.3mgL^-1), Hg (0.001mgL^-1) and their mixture for 12, 24, 48, 72 and 96h. Biomarkers of genotoxicity (comet assay and micronucleus test) and cytotoxicity (caspase-3 activity and TUNEL assay) were evaluated. Significant increases relative to the control group (p<0.05) were observed in all biomarkers at all exposure times in all test systems; however, damage was greater when the metals were present as a mixture. Furthermore, correlations between metal concentrations and biomarkers of geno- and cytotoxicity were found only at certain exposure times. In conclusion, Al, Fe, Hg and the mixture of these metals induce geno- and cytotoxicity on blood of C. carpio.

Acute exposure to a quinalphos containing insecticide (convoy) causes genetic damage and nuclear changes in peripheral erythrocytes of silver barb, Barbonymus gonionotus

The present study was aimed to assess the genotoxic effect in fish caused by convoy, an insecticide commercial formulation containing quinalphos, present in the aquatic waterbody. For this purpose a freshwater teleost, silver barb was exposed to sublethal concentrations (25% and 50% of LC₅₀) of convoy and erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) tests were performed in addition to the commonly used micronucleus (MN) assay using peripheral erythrocytes and DNA contents in the different tissues after 1, 24, 36, 48, and 72 h of exposures. The obtained results indicated that acute exposure of different sub lethal concentrations of convoy to the fish resulted in significant alterations of erythrocytes as well as significant reduction of DNA contents in blood and vital organs and tissues, such as the brain, liver, kidney and muscle. Compared to each treatment excluding control group, frequencies of ECA, ENA, and MN were found to be elevated with exposure time of the doses. From this study, we conclude that convoy is a hazardous chemical to silver barb. Bioassays can be used as a tool for screening aquatic pollution, especially for insecticides.

Micronuclei and Nuclear Abnormalities in Erythrocytes from Barbel Barbus peloponnesius Revealing Genotoxic Pollution of the River Bregalnica

The strong negative anthropogenic pressure on the River Bregalnica resulted in the increase of pollution in the river ecosystem. The aim of this study was to evaluate if aquatic pollutants generate genotoxic effects in barbel (Barbus peloponnesius). Thirty individuals were collected from three localities along the river: one control site and two locations in the middle and lower course of the river with the presence of different pollution sources. Blood smears were stained with May-Grünwald/Giemsa method and the frequency of micronuclei, vacuolated nuclei, binuclei, blebbed nuclei and notched nuclei expressed in per mill was recorded. In fish collected from the control site, the investigated erythrocyte nuclear abnormalities revealed lowest values compared to polluted sites. In general, significantly higher values for erythrocyte deformations, including micronuclei, were noted in the middle and lower part of the river. Significantly higher values of vacuolated and blebbed nuclei were detected in fish from the middle course of the river, while at the lower course the frequencies of occurrence of micronuclei and notched nuclei were significant compared with control site. The middle course of the River Bregalnica has more diverse pollutants compared to the lower course, and consequently the highest frequency of all nuclear deformations was found in barbel from the middle course of the river. Obtained results suggest that pollutants draining into the Bregalnica river ecosystem display a genotoxic effect on the local barbel population.

Active biomonitoring of mussels Mytilus galloprovincialis with integrated use of micronucleus assay and physiological indices to assess harbor pollution

The mussels Mytilus galloprovincialis collected from a noncontaminated site (Chaib Rasso) were transplanted during one, three and six months at Ghazaouet harbor (GH), areas with a strong gradient of pollution. The micronucleus test (MN) was selected to monitor the impact of contamination, along with physiological indexes (condition index CI and organo-somatic indexes RI and GSI). The results show a negative correlation of MN variation in gill cells with CI but a positive correlation with transplantation duration. However, a significant correlation was found between the indexes. Moreover, the findings indicate that MN in the hemolymph and gills of transplanted mussels for one, three and six months at GH are significantly higher than those of the reference site. However, no significant differences were noted between the three transplants at the two organs. Monitoring the physiological status of mussels, in parallel with the biomarker measurements, is useful in assessing the impact of contaminants.

Oxidative stress and genotoxicity induced by ketorolac on the common carp Cyprinus carpio

The nonsteroidal anti-inflammatory drug ketorolac is extensively used in the treatment of acute postoperative pain. This pharmaceutical has been found at concentrations of 0.2-60 µg/L in diverse water bodies around the world; however, its effects on aquatic organisms remain unknown. The present study, evaluated the oxidative stress and genotoxicity induced by sublethal concentrations of ketorolac (1 and 60 µg/L) on liver, brain, and blood of the common carp Cyprinus carpio. This toxicant induced oxidative damage (increased lipid peroxidation, hydroperoxide content, and protein carbonyl content) as well as changes in antioxidant status (superoxide dismutase, catalase, and glutathione peroxidase activity) in liver and brain of carp. In blood, ketorolac increased the frequency of micronuclei and is therefore genotoxic for the test species. The effects observed were time and concentration dependent. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1035-1043, 2016.

Fish liver and gill cells as cytogenotoxic indicators in assessment of water quality

The present study was aimed to evaluate the effect of municipal wastewater of Tung Dhab drain to freshwater fish Labeo rohita through genotoxicity assays. The idea is to explore and standardize procedures for assessment of toxic impact of pollutant at the cellular level in aquatic species. Hence, chronic, non-renewal toxicity tests were performed with sublethal concentrations (17.7, 26.6 and 35.4 %) of wastewater for exposure durations of 15, 30 and 60 days. Recovery experiments were also performed for duration of 60 days. Higher micronuclei (MN) and binuclei (BN) frequencies were recorded in fluorescently stained liver cells as compared to frequencies obtained for gill cells and erythrocytes. The induced frequencies of MN, BN and nuclear abnormalities (NA) were found in the following order: MN (liver cells) > BN (liver cells) > BN (gill cells) > MN (gill cells) > NA (erythrocytes) > MN (erythrocytes). The results pointed towards the mutagenic nature of water quality of Tung Dhab drain and recommend the incorporation of the liver and gill cells as biomarkers of cytotoxicity over erythrocytes in chronic experiments during water monitoring programs.

Combination of physico-chemical analysis, Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay/nuclear abnormalities tests for cyto-genotoxicity assessments of treated effluents discharged from textile industries

Bioassays for cyto-genotoxicity assessments are generally not required in current textile industry effluent discharge management regulations. The present study applied in vivo plant and fish based toxicity tests viz. Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay and nuclear abnormalities tests in combination with physico-chemical analysis for assessing potential cytotoxic/genotoxic impacts of treated textile industry effluents reaching a major river (Kelani River) in Sri Lanka. Of the treated effluents tested from two textile industries, color in the Textile industry 1 effluents occasionally and color, biochemical oxygen demand and chemical oxygen demand in the Textile industry 2 effluents frequently exceeded the specified Sri Lankan tolerance limits for discharge of industrial effluents into inland surface waters. Exposure of A. cepa bulbs to 100% and 12.5% treated effluents from both industries resulted in statistically significant root growth retardation, mito-depression, and induction of chromosomal abnormalities in root meristematic cells in comparison to the dilution water in all cases demonstrating cyto-genotoxicity associated with the treated effluents. Exposure of O. niloticus to the 100% and 12.5% effluents, resulted in erythrocytic genetic damage as shown by elevated total comet scores and induction of nuclear abnormalities confirming the genotoxicity of the treated effluents even with 1:8 dilution. The results provide strong scientific evidence for the crucial necessity of incorporating cyto-genotoxicity impact assessment tools in textile industry effluent management regulations considering human health and ecological health of the receiving water course under chronic exposure.

Multilevel assessment of ivermectin effects using different zebrafish life stages

Several studies have shown high toxicity of the veterinary pharmaceutical ivermectin (a semisynthetic avermectin) for aquatic invertebrates however, few data is found for fish species. The present study evaluated the toxicity of ivermectin, to embryos, juveniles, and adults of zebrafish at different levels of biological organization including developmental, behavioural and biochemical. Toxicity tests were performed based on OECD protocols and mortality and behavioural changes were assed for all stages. Biochemical responses were assessed in adults and embryos and included cholinesterases (ChEs), catalase (CAT) (only in embryos), glutathione-S-Transferase (GST), lactate dehydrogenase (LDH) and vitellogenin (VTG) like proteins (only in embryos). Genotoxicity was evaluated in adults. Results showed a higher sensitivity of juvenile and adults of zebrafish (96h-LC10 values of 14.0 and 55.4μg/L, respectively). For embryos a 96h-LC10 of 147.1μg/L was calculated, moreover developmental anomalies and hatching inhibition were observed only at high concentrations (>400μg/L), whereas biochemical and behavioural responses occurred at lower concentrations (<60μg/L). Behavioural responses (lethargy) occurred in all life stages. Biochemical responses were observed including the inhibition of GST in adults and changes in ChE, CAT, LDH activities and VTG levels in embryos. Ivermectin did not show to be genotoxic for adult fish. The species sensitivity distribution analysis, based on fish and invertebrate species, indicated a Hazardous Concentration for 5% of the population (HC5) value of 0.057μg/L; suggesting high sensitivity of both groups to ivermectin and a high risk of this compound to aquatic ecosystems.

Multibiomarker toxicity characterization of uranium mine drainages to the fish Carassius auratus

The release of acidic effluents, naturally enriched in metals and radionuclides, is the main legacy of uranium mines. Generally, metals dissolved by these acidic effluents can cause significant alterations in exposed organisms, with distinct toxicological outcomes. In this study, 72 individuals of the freshwater fish species Carassius auratus were exposed in situ for different periods (8, 16, 24, and 48 h) to water from a pond (treatment pond (TP)) with a chemically treated effluent and a reference pond (PRP), in the vicinity of the Cunha Baixa uranium mine (Portugal). Comparing the water of the two ponds, the PRP pond was characterized by higher pH and oxygen values and lower conductivity and hardness values. Regarding total metal concentrations, among others, magnesium (56,000 μg/L), sodium (17,400 μg/L), zinc (86 μg/L), manganese (6340 μg/L), and uranium (1380 μg/L) concentrations in the TP pond were above the values obtained for the PRP pond. The values of manganese and uranium exceeded the values of quality criteria established for surface waters for cyprinids and for irrigation purposes. After exposure to pond water, significant differences were recorded for several biomarkers: (i) between ponds for acetylcholinesterase (AChE) with higher activities for animals from the PRP and glutathione-S-transferase (GST) activities that were particularly enhanced in animals from the TP pond; (ii) between ponds and exposure periods for lactate dehydrogenase (LDH) activity, since organisms from PRP pond presented always higher values than those from the TP pond, and among these, organisms exposed for the longer period presented a further depression in LDH activity; and (iii) between exposure periods for erythrocyte micronucleus. GSTs and LDH were the most sensitive biomarkers within the timeframe of the in situ assay performed. Despite the alleged efficacy of the chemical treatment (evidenced by a significantly lower pH), some metals persisted in the treated effluent (TP pond), potentially contributing to the induction of oxidative stress or increased conjugation metabolic activity in fish.

Toxic and genotoxic effects of the 2,4-dichlorophenoxyacetic acid (2,4-D)-based herbicide on the Neotropical fish Cnesterodon decemmaculatus

Acute toxicity and genotoxicity of the 54.8% 2,4-D-based commercial herbicide DMA® were assayed on Cnesterodon decemmaculatus (Pisces, Poeciliidae). Whereas lethal effect was used as the end point for mortality, frequency of micronuclei (MNs), other nuclear abnormalities and primary DNA damage evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Mortality studies demonstrated an LC50 96 h value of 1008 mg/L (range, 929-1070) of 2,4-D. Behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, slow reaction and abnormal swimming were observed. Exposure to 2,4-D within the 252-756 mg/L range increased the frequency of MNs in fish exposed for both 48 and 96 h. Whereas blebbed nuclei were induced in treatments lasting for 48 and 96 h, notched nuclei were only induced in fish exposed for 96 h. Regardless of both concentration and exposure time, 2,4-D did not induce lobed nuclei and binucleated erythrocytes. In addition, we found that exposure to 2,4-D within the 252-756 mg/L range increased the genetic damage index in treatments lasting for either 48 and 96 h. The results represent the first experimental evidence of the lethal and several sublethal effects, including behavioral alterations and two genotoxic properties namely the induction of MNs and primary DNA strand breaks, exerted by 2,4-D on an endemic organism as C. decemmaculatus.

Water mutagenic potential assessment on a semiarid aquatic ecosystem under influence of heavy metals and natural radioactivity using micronuclei test

The contamination of water bodies by heavy metals and ionizing radiation is a critical environmental issue, which can affect water quality and, thus, human health. This study aimed to evaluate the water quality of the Boqueirão de Parelhas Dam in the Brazilian semiarid region. A 1-year study (2013-2014) was performed through the assessment of physicochemical parameters, heavy metal content, and radioactivity along with the mutagenicity potential of water using micronuclei test in Orechromis niloticus (in vivo) and the cytokinesis-block micronucleus (CBMN) assay in human lymphocytes (in vitro). A deterioration of water organoleptics characteristics by the presence of high levels of sulfate and total solids was observed. High concentrations of aluminum, nickel, silver, and lead along with the alpha particle content were higher than the limits suggested by the World Health Organization and Brazilian legislation for drinking water. An increase in the frequency of micronuclei and nuclear abnormalities was observed in both experimental models. The results obtained confirmed the mutagenic potential present in water samples. This study highlights that geogenic agents affect water quality becoming a human health concern to be taken into account due to the relevance that this water reservoir has in the region.

Using genotoxic and haematological biomarkers as an evidence of environmental contamination in the Ocoa River native fish, Villavicencio-Meta, Colombia

The studies evaluating the impact of environmental pollution on aquatic organisms have had a growing concern in recent decades. The Ocoa River runs through Villavicencio city, receiving the wastewater produced in the city. To date studies reporting the effect and the consequences of Ocoa River pollution on aquatic organisms inhabiting this water body are unknown. Haematological and genotoxicity biomarkers were evaluated in peripheral blood of two native fish species Astyanax gr. bimaculatus and Aequidens metae during rainy and dry season at three different sites of Ocoa River called Nacimiento (site 1, before entering the city), Centauros (site 2, inside the city), Caño Seco (site 3, after the city). Also, fish from a reference site with little likelihood of contamination were sampled. Alterations such as decrease in erythrocyte count, lymphocytes, haemoglobin concentration and haematocrit percentage, and increased thrombocytes and neutrophils counts, together with nuclear abnormalities in erythrocytes such as increased frequency of micronuclei, lobed, blebbed and notched nuclei and binucleate cells were observed in fish from the site 3, followed by the site 2 in rainy season. These results shown that during rainy season, sites 2 and 3 receive domestic and industrial wastewater leading to genotoxic and haematological changes in the monitored organisms.

Assessing genotoxic effects in fish from a marine protected area influenced by former mining activities and other stressors

The goal of the current study was to evaluate different genotoxicity tools in order to assess a marine protected area (MPA) affected by former mining activities and urban settlements. A catfish (Cathorops spixii) was analyzed for genotoxic effects at the (i) molecular and at the (ii) chromosomal levels. Through factor analysis, genotoxicity was found to be linked to levels of metals bioaccumulated and PAH metabolites in the bile. Micronucleus and nuclear alteration were less vulnerable to the effects of confounding factors in mildly contaminated areas since they were more frequently associated with bioaccumulated metals than the DNA analysis. The different genotoxicity responses allowed for the identification of sources of pollution in the MPA. This approach was important for detecting environmental risks related to genotoxic contaminants in a mildly contaminated MPA.

Photochemical degradation increases polycyclic aromatic hydrocarbon (PAH) toxicity to the grouper Epinephelus marginatus as assessed by multiple biomarkers

The effects of halogen-light-irradiated and non-irradiated PAHs on the grouper Epinephelus marginatus were assessed through biomarkers including morphometric parameters, liver histopathology, biliary PAH concentration, genetic alterations, and enzyme activity modulation. E. marginatus juveniles were divided into three groups: control (C), non-irradiated PAHs (PAHs1), and irradiated PAHs (PAHs2). Test groups were exposed for 14 days to a 0.5 ppm PAH solution in the semi-static system. After this period, fish were anesthetized with benzocaine (2%) and peripheric blood was collected by caudal puncture. Blood smears were prepared and stained with propidium iodide. Fish livers were collected, fixed in McDowell's solution, embedded in paraplast, thin-sectioned, and stained with hematoxylin-eosin (H&E). For biochemical analyses including superoxide dismutase, catalase, and glutathione S-transferase activities, fish livers were collected and preserved in liquid nitrogen. Water samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and bile synchronous fluorescence spectroscopy. Fish in the PAHs2 group had micronuclei (MN) in blood cells, as well as significant differences in nuclear morphology (NMA). Significant morphological alterations were observed in the livers from fish exposed to PAHs as well as inhibition of the catalase activity. Our results show that irradiation altered the bioavailability of PAHs, especially benzanthracene, which has great impact in aquatic ecosystems. Among the consequences of physical and chemical changes to PAHs, we observed a significant increase in NMA and MN incidence in E. marginatus erythrocytes, indicating the potential initiation of mutagenic and carcinogenic processes.

The impact of water pollution on fish species in southeast region of Goiás, Brazil

The rivers from the region of Catalão, Southeast Goiás State, Brazil, are exposed to intense anthropogenic influences including agricultural activities, industry, and urban waste. The aim of this study was to determine the severity of water pollution by conducting an experiment involving in situ biomonitoring of water constituents on genotoxicity in fish inhabiting these sites. The genotoxicity of three sites of the region were analyzed utilizing the micronucleus (MN) test. It was of interest to determine whether there were differences between sampling sites such as urban perimeter, agriculture, and fertilizer industry in control, and monitored species including Astyanax fasciatus, Astyanax altiparanae, and Characidium fasciatum. Data demonstrated that the species at sites 1, 2, and 3 exhibited a marked increase in frequency of MN compared to fish from site 4. Significant elevation in frequency of MN occurred in erythrocytes of A. fasciatus and A. altiparanae at sites 1 and 2. At site 3 higher frequencies of MN were observed in C. fasciatum. MN induction in C. fasciatum was correlated with chromium levels in water and sediment, while A. fasciatum and A. altiparanae showed an association with zinc in water and sediment. Data suggest that benthic and nektonic fish species display different sensitivities in relation to anthropogenic contaminant influences.

What the Erythrocytic Nuclear Alteration Frequencies Could Tell Us about Genotoxicity and Macrophage Iron Storage?

Erythrocytic nuclear alterations have been considered as an indicative of organism’s exposure to genotoxic agents. Due to their close relationship among their frequencies and DNA damages, they are considered excellent markers of exposure in eukaryotes. However, poor data has been found in literature concerning their genesis, differential occurrence and their life span. In this study, we use markers of cell viability; genotoxicity and cellular turn over in order to shed light to these events. Tilapia and their blood were exposed to cadmium in acute exposure and in vitro assays. They were analyzed using flow cytometry for oxidative stress and membrane disruption, optical microscopy for erythrocytic nuclear alteration, graphite furnace atomic absorption spectrometry for cadmium content in aquaria water, blood and cytochemical and analytical electron microscopy techniques for the hemocateretic aspects. The results showed a close relationship among the total nuclear alterations and cadmium content in the total blood and melanomacrophage centres area, mismatching reactive oxygen species and membrane damages. Moreover, nuclear alterations frequencies (vacuolated, condensed and blebbed) showed to be associated to cadmium exposure whereas others (lobed and bud) were associated to depuration period. Decrease on nuclear alterations frequencies was also associated with hemosiderin increase inside spleen and head kidney macrophages mainly during depurative processes. These data disclosure in temporal fashion the main processes that drive the nuclear alterations frequencies and their relationship with some cellular and systemic biomarkers.

NSAID-manufacturing plant effluent induces geno- and cytotoxicity in common carp (Cyprinus carpio)

The pharmaceutical industry generates wastewater discharges of varying characteristics and contaminant concentrations depending on the nature of the production process. The main chemicals present in these effluents are solvents, detergents, disinfectants - such as sodium hypochlorite (NaClO) - and pharmaceutical products, all of which are potentially ecotoxic. Therefore, this study aimed to evaluate the geno- and cytotoxicity induced in the common carp Cyprinus carpio by the effluent emanating from a nonsteroidal anti-inflammatory drug (NSAID)-manufacturing plant. Carp were exposed to the lowest observed adverse effect level (LOAEL, 0.1173%) for 12, 24, 48, 72 and 96 h, and biomarkers of genotoxicity (comet assay and micronucleus test) and cytotoxicity (caspase-3 activity and TUNEL assay) were evaluated. A significant increase with respect to the control group (p<0.05) occurred with all biomarkers from 24h on. Significant positive correlations were found between NSAID concentrations and biomarkers of geno- and cytotoxicity, as well as among geno- and cytotoxicity biomarkers. In conclusion, exposure to this industrial effluent induces geno- and cytotoxicity in blood of C. carpio.

Toxic and genotoxic effects of the imazethapyr-based herbicide formulation Pivot H® on montevideo tree frog Hypsiboas pulchellus tadpoles (Anura, Hylidae)

Acute lethal and sublethal toxicity of the imidazolinone imazethapyr (IMZT)-based commercial formulation herbicide Pivot H® (10.59% IMZT) was evaluated on Hypsiboas pulchellus tadpoles. Whereas mortality was used as the end point for lethality, frequency of micronuclei (MNs) and other nuclear abnormalities as well as DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed to test genotoxicity. Behavioral, growth, developmental, and morphological abnormalities were also employed as sublethal end points. Mortality studies revealed equivalent LC50 (96h) values of 1.49mg/L (confidence limit, 1.09-1.63) and 1.55mg/L (confidence limit, 1.51-1.60) IMZT for Gosner stage (GS) 25 and GS36, respectively. Behavioral changes, i.e., irregular swimming and immobility, as well as a decreased frequency of keratodonts were observed. The herbicide increased the frequency of MNs in circulating erythrocytes of tadpoles exposed for 48h to the highest concentration assayed (1.17mg/L). However, regardless of the concentration of the herbicide assayed, an enhanced frequency of MNs was observed in tadpoles exposed for 96h. The herbicide was able to induce other nuclear abnormalities, i.e., blebbed and notched nuclei, only when tadpoles were exposed for 96h. In addition, we observed that exposure to IMZT within the 0.39-1.17mg/L range increased the genetic damage index in treatments lasting for both 48 and 96h. This study represents the first evidence of acute lethal and sublethal effects exerted by IMZT on amphibians. Finally, our findings highlight the properties of this herbicide that jeopardize nontarget living species exposed to IMZT.

In vivo genotoxicity and cytotoxicity assessment of cadmium chloride in peripheral erythrocytes of Labeo rohita (Hamilton)

Cadmium chloride (CdCl2) induced genotoxicity and cytotoxicity has been assessed in the peripheral blood erythrocytes of freshwater fish Labeo rohita exposed to 0.37 and 0.62mg/L of CdCl2 in water for 100 days. The blood samples of the fish were collected at different intervals (days 1, 3, 5, 10, 15, 30, 60 and 100) of exposure period to analyze DNA damage using comet assay and the occurrence of micronuclei and other cellular anomalies. The results of comet assay showed a significant increase in the mean percentage of tail DNA at both the concentrations. Exposure to CdCl2 also induced micronuclei in addition to many nuclear abnormalities such as nuclear bud, binucleates, lobed, notched and vacuolated nuclei. Cytoplasmic abnormalities like echinocytes, acanthocytes, notched, microcytes and cells with vacuolated cytoplasm were also observed. The metal exposed groups showed significant variation in the frequency of cellular abnormalities as well as the extent of DNA damage in comparison to controls. These frequencies increased significantly (p<0.05) in concentration dependent manner, peaking on 10th day while a decreasing trend was observed after 15 days of the exposure period.

Seahorse (Hippocampus reidi) as a bioindicator of crude oil exposure

This study explored the suitability of the seahorse Hippocampus reidi (Ginsburg, 1933) for assessing biomarkers of genotoxic effects and its use as a sentinel organism to detect the effects of acute exposure to petroleum hydrocarbons. Fish were exposed to three concentrations of crude oil (10, 20 and 30 g/kg) for 96 h, and the activity of phase II biotransformation enzyme glutathione S-transferase (GST) was measured. In addition, we performed genotoxicity assays, such as comet assay, micronucleus (MN) test and nuclear abnormalities (NA) induction, on the erythrocytes of the fish species. Our results revealed that the inhibition of hepatic GST activity in H. reidi was dependent on increasing crude oil concentrations. In contrast, an increase in the damage index (DI) and MN frequency were observed with increased crude oil concentrations. These results indicate that the alkaline comet assay and micronucleus test were suitable and useful in the evaluation of the genotoxicity of crude oil, which could improve determinations of the impact of oil spills on fish populations. In addition, H. reidi is a promising "sentinel organism" to detect the genotoxic impact of petroleum hydrocarbons.

Cytogenotoxicity assessment of monocrotophos and butachlor at single and combined chronic exposures in the fish Catla catla (Hamilton)

Cytogenotoxic effects in the form of micronuclei and deformed nucleus, nuclear buds, binucleated cells, vacuolated nucleus, vacuolated cytoplasm, echinocytes, and enucleus induced by two compounds belonging to two different chemical classes of agrochemicals (monocrotophos and butachlor) at sublethal concentrations (0.625, 1.3, and 2.3 ppm and 0.016, 0.032, and 0.064 ppm) in single and combined chronic exposures were studied under laboratory conditions for a period of 35 days in the economically important Indian fish Catla catla. Statistically significant duration-dependent increases in the frequencies of micronucleus (MN) and other cytological anomalies were observed. Compared to single exposures, a twofold increase in micronuclei frequency was noted at combined exposures indicating the synergistic phenomenon. Binucleated and enucleated cells appeared only in fishes exposed to sublethal concentrations of butachlor. The present study is the first of its kind in exploring a significant positive correlation between micronuclei and other nuclear anomalies suggesting them as new possible biomarkers of genotoxicity after agrochemical exposures. The study highlights the sensitivity of the assay in exploring various predictive biomarkers of genotoxic and cytotoxic events and also elicits the synergistic effects of agrochemicals in apparently healthy fishes. C. catla can be considered as a suitable aquatic biomonitoring sentinel species of contaminated water bodies.

Oxidative stress and hypermethylation induced by exposure of Oreochromis niloticus to complex environmental mixtures of river water from Cubatão do Sul, Brazil

In this study, we investigated the effects of oxidative stress and hypermethylation through lipid peroxidation and DNA methylation, respectively, in erythrocytes of Oreochromis niloticus exposed to environmental complex mixture of water from Cubatão do Sul River throughout the year. This river is the source of drinking water for the region of Florianópolis, the capital of Santa Catarina State, Brazil. Lipid peroxidation was quantified by the rate of malondialdehyde (MDA) formation, and DNA methylation was quantified by the rate of 5-methyldeoxycytosine (m(5)dC) formation. In all studied sites, the river water samples caused metabolic changes in O. niloticus. MDA formation rates were significantly different when compared to the negative control (except for samples from Site 1 during spring 2010, summer 2011 and fall 2011). All samples (except Site 1, spring 2010) induced increases in the m(5)dC formation rates, and at the end of the study, the values were near the values found in the positive control (potassium dichromate 2.5mg/L). The results showed that samples of environmental complex mixtures of water from Cubatão do Sul River are capable of inducing high levels of oxidative damage and hypermethylation in O. niloticus.

Hematological and biochemical investigations on the effect of vitamin E and C on Oreochromis niloticus exposed to zinc oxide nanoparticles

This study was carried out to determine the LC₅₀ of zinc oxide nanoparticles (ZnONPs) on Oreochromis niloticus and to investigate the effect of vitamin E and C on hematological and biochemical alterations induced by two sublethal concentrations (1 and 2 mg/L) of ZnONPs. One hundred and eighty fish were used for studying the lethal concentrations of ZnONPs. For sublethal study two hundred and twenty-five males of O. niloticus were equally divided into five groups, control, the second and the third were treated with 1 and 2 mg/L ZnONPs respectively. The fourth and fifth were exposed to the same concentrations of ZnONPs plus vitamins E and C. The results revealed that the 96 h LC₅₀ of ZnONPs was 3.1 ± 0.4 mg/L. The sublethal study revealed the presence of normocytic normochromic anemia in groups (2, 3 and 5) along the experiment period. The 4th group showed normocytic normochromic anemia at the 7th day and microcytic hypochromic anemia at the 15th day. Leukocytosis, heterophilia, lymphopenia and monocytopenia were recorded at the 7th day in all treated groups compared with the normal control. At the 15th day heteropenia, lymphopenia and monocytopenia were reported in all treated groups. A significant increase in the serum levels of alkaline phosphatase, aminotransferases, urea, creatinine and erythrocytic nuclear and morphological abnormalities along the experimental periods in all treated groups compared with the normal control. Serum total protein and albumin levels were significantly decreased at the same period in the same groups. Addition of vitamin E and C to the diet (groups 4 and 5) significantly improved all measured parameters compared with groups (2 and 3) which treated with ZnONPs only.

Assessing the environmental genotoxicity risk in the Baltic Sea: frequencies of nuclear buds in blood erythrocytes of three native fish species

Nuclear bud (NB) formation was investigated in blood erythrocytes of 1892 flounder Platichthys flesus, herring Clupea harengus, and eelpout Zoarces viviparus specimens that were collected at 82 sites representing different regions of the Baltic Sea in 2009-2011. This is the first attempt to evaluate the baseline levels of NB and rank the genotoxicity risk for native fish species. NB levels were compared to the previously published micronuclei (MN) data from the same individual fish specimens in order to compare the two methods of genotoxicity assessment and investigate the relationship between MN as the cytogenetic measure of genotoxicity and the DNA damage reflecting NB. In 2009-2011, elevated NB levels in 89.4% of flounder sampling groups indicated high and extremely high genotoxicity risk levels. Herring and eelpout sampling groups showed elevated levels of NB, 74.6 and 45.7%, respectively. In general, herring and eelpout NB measure was more sensitive as the genotoxicity biomarker than MN.

In situ assessment of a neotropical fish to evaluate pollution in a river receiving agricultural and urban wastewater

We aimed to assess the quality of a midsize river that receives agricultural and urban wastewater. Nuclear abnormalities (NA), comet assays of blood and gills, and gill histopathology were evaluated in fish Astyanax aff. paranae during the summer and winter 2011 at three sites in Paraná State, Brazil: (1) a biological reserve (Rebio-reference area); (2) an agricultural site; (3) a downstream site that accumulates agricultural and urban effluents. We found the highest effects of pollutants in fish at the downstream site during the summer. The agricultural site showed an intermediate damage rate, and fish at Rebio generally had the least damage, with the exception of NA. Despite conflicting results from the biomarkers used, we observed an increase in damage associated with the accumulation of pollutants. Pesticides are probable xenobiotics in the agricultural area. Additionally, metals and substances such as pharmaceuticals and ammonia may be present at the downstream site.

Developmental toxicity of PAH mixtures in fish early life stages. Part II: adverse effects in Japanese medaka

In aquatic environments, polycyclic aromatic hydrocarbons (PAHs) mostly occur as complex mixtures, for which risk assessment remains problematic. To better understand the effects of PAH mixture toxicity on fish early life stages, this study compared the developmental toxicity of three PAH complex mixtures. These mixtures were extracted from a PAH-contaminated sediment (Seine estuary, France) and two oils (Arabian Light and Erika). For each fraction, artificial sediment was spiked at three different environmental concentrations roughly equivalent to 0.5, 4, and 10 μg total PAH g(-1) dw. Japanese medaka embryos were incubated on these PAH-spiked sediments throughout their development, right up until hatching. Several endpoints were recorded at different developmental stages, including acute endpoints, morphological abnormalities, larvae locomotion, and genotoxicity (comet and micronucleus assays). The three PAH fractions delayed hatching, induced developmental abnormalities, disrupted larvae swimming activity, and damaged DNA at environmental concentrations. Differences in toxicity levels, likely related to differences in PAH proportions, were highlighted between fractions. The Arabian Light and Erika petrogenic fractions, containing a high proportion of alkylated PAHs and low molecular weight PAHs, were more toxic to Japanese medaka early life stages than the pyrolytic fraction. This was not supported by the toxic equivalency approach, which appeared unsuitable for assessing the toxicity of the three PAH fractions to fish early life stages. This study highlights the potential risks posed by environmental mixtures of alkylated and low molecular weight PAHs to early stages of fish development.

Induction of micronuclei and nuclear lesions in Channa punctatus following exposure to carbosulfan, glyphosate and atrazine

The genotoxic effects of commonly used agricultural pesticides viz., carbosulfan, glyphosate, and atrazine, were evaluated in Channa punctatus (Pisces, Perciformes) using micronucleus (MN) test and induction of nuclear lesions (NL). The 96 h LC50 value were estimated by probit analysis as 0.27, 32.0 and 42.0 mg L(-1), respectively, for carbosulfan, glyphosate, and atrazine using semi-static bioassays. Based on these values, three sublethal test concentrations of carbosulfan (0.07, 0.13, 0.20 mg L(-1)), glyphosate (8.1, 16.3, 24.4 mg L(-1)) and atrazine (10.6, 21.2, 31.8 mg L(-1)) corresponding to ¼, ½ and ¾ of the LC50 of the pesticides respectively, were selected for exposure for 96 h. Peripheral blood samplings were taken at intervals of 24 h for assessment of MN and NL frequencies. Considerably higher genotoxic damage was induced by carbosulfan as compared to glyphosate and atrazine. There were significant effects (p < 0.01) of concentrations in all the treated groups. The induction of MN and NL was highest at 96 h pesticide exposure at all test concentrations. The nuclear abnormalities recorded in this study, such as blebbed-, lobed-, notched- and bi-nuclei, other than micronuclei, are indicators of genotoxic damage.

The role of vitamins A, C, E and selenium as antioxidants against genotoxicity and cytotoxicity of cadmium, copper, lead and zinc on erythrocytes of Nile tilapia, Oreochromis niloticus

This study was carried out to investigate the genotoxic and cytotoxic potentials of sublethal concentration (5mg L(-1)) of combined metals including Cd, Cu, Pb and Zn (1.25mg L(-1) of each) on erythrocytes of Nile tilapia, Oreochromis niloticus after exposure for five and seven days; and to evaluate the protective role of vitamin E alone and a combination of selenium (Se) with vitamins A, C and E which was added to the diet as antioxidants against the genotoxicity and cytotoxicity of these metals. This was accomplished by application of micronuclei (MN), binuclei (BN), nuclear abnormalities (NAs) assays in addition to morphological erythrocyte alteration (MAEs) assay. The results revealed that, exposure of O. niloticus to Cd, Cu, Pb and Zn induced the formation of nine genotoxic endpoints including MN, BN and seven patterns of NAs, kidney-shaped nuclei, blebbed nuclei, lobed nuclei, bilobed nuclei, notched nuclei, hook-shaped nuclei and vacuolated nuclei; and five patterns of morphological malformations were recorded as cytotoxic endpoints including echinocytes, acanthocytes, teardrop-like erythrocytes, microcytes and fused erythrocytes. Frequencies of these abnormalities were significantly different (p<0.05) in comparison to control group. The maximum number of MN, BN and most of NAs and MAEs were recorded in the 5th day of exposure and then start to decrease as recorded in the 7th day. Addition of the vitamin E alone to the diet significantly (p<0.05) decreased the frequencies of MN, BN, and most of NAs and MAEs to become less than those recorded in metals-treated fish. But, addition of a combination of Se with vitamins A, C and E in the diet resulted in more significant decrease (p<0.05) in frequencies of MN, BN, NAs and most MAEs to become less than those recorded in both, fish treated with metals only and fish treated with metals and supplied with vitamin E alone in the diet. Therefore, this study confirms the powerful protective potential of the vitamin E alone and a combination of SE with vitamins A, C and E as antioxidants against the genotoxicity and cytotoxicity of Cd, Cu, Pb and Zn in erythrocytes of O. niloticus. Also, confirmed on the validity of MN test and NAs in addition to MAEs as effective indicators and valuable sensitive monitoring tools for detecting genotoxic and cytotoxic agents in the aquatic environment.

Frequency of micronuclei and of other nuclear abnormalities in erythrocytes of the grey mullet from the Mondego, Douro and Ave estuaries--Portugal

Fish are bioindicators of water pollution, and an increased rate of their erythrocyte nuclear morphological abnormalities (ENMAs)-and particularly of erythrocyte micronuclei (EMN)-is used as a genotoxicity biomarker. Despite the potential value of ENMAs and MN, there is scarce information about fish captured in Iberian estuaries. This is the case of the Portuguese estuaries of the Mondego, Douro and Ave, suffering from different levels of environmental stress and where chemical surveys have been disclosing significant amounts of certain pollutants. So, the aim of this study was to evaluate genotoxicants impacts and infer about the exposure at those ecosystems, using the grey mullet (Mugil cephalus) as bioindicator and considering the type and frequency of nuclear abnormalities of erythrocytes as proxies of genotoxicity. Sampling of mullets was done throughout the year in the important Mondego, Douro and Ave River estuaries (centre and north-western Portugal). The fish (total n = 242) were caught in campaigns made in spring-summer and autumn-winter, using nets or fishing rods. The sampled mullets were comparable between locations in terms of the basic biometric parameters. Blood smears were stained with Diff-Quik to assess the frequencies of six types of ENMAs and MN (given per 1,000 erythrocytes). Some basic water physicochemical parameters were recorded to search for fluctuations matching the ENMAs. Overall, the most frequent nucleus abnormality was the polymorphic type, sequentially followed by the blebbed/lobed/notched, segmented, kidney shaped, vacuolated, MN and binucleated. The total average frequency of the ENMAs ranged from 73 ‰ in the Mondego to 108 ‰ in the Ave. The polymorphic type was typically ≥50 % of the total ENMAs, averaging about 51 ‰, when considering all three estuaries. The most serious lesion-the MN-in fish from Mondego and Douro had a similar frequency (≈0.38 ‰), which was significantly lower than that in the Ave (0.75 ‰). No significant seasonal differences existed as to the MN rates and seasonal differences existed almost only in the Douro, with the higher values in AW. In general, the pattern of ENMAs frequencies was unrelated with the water physicochemical parameters. Considering the data for both the total ENMAs and for each specific abnormality, and bearing in mind that values of MN in fish erythrocytes >0.3 ‰ usually reflect pollution by genotoxicants, it is suggested that mullets were likely being chronically exposed to such compounds, even in the allegedly less polluted ecosystem (Mondego). Moreover, data supported the following pollution exposure gradient: Mondego < Douro < Ave. The scenario and inferences nicely agree with the published data from chemical monitoring.

Assessment of genotoxic and mutagenic potential of hexavalent chromium in the freshwater fish Labeo rohita (Hamilton, 1822)

The present study was undertaken to investigate the genotoxicity and mutagenicity of sublethal concentrations of hexavalent chromium (potassium dichromate) in the Indian major carp, Labeo rohita. The 96 h LC50 value of potassium dichromate estimated was 118 mg L(-1) by probit analysis using SPSS (version 16.0) software. Based on 96 h LC50 value, three sublethal test concentrations of potassium dichromate (29.5, 59.0 and 88.5 mg L(-)(1)) were selected and specimens were exposed in vivo to these test concentrations for 96 h. The mutagenic and genotoxic effects of potassium dichromate were evaluated in gill and blood cells using micronucleus (MN) test and comet assay. In general, significant (p < 0.05) effects due to the concentrations and the exposure durations were observed in exposed specimens. The MN induction was highest at 96 h at all the test concentrations in the peripheral blood. A similar trend was observed for the DNA damage, measured in terms of percentage of tail DNA, in erythrocyte and gill cells. The study indicated hazardous effect of the hexavalent chromium to fish and other aquatic organisms and indirectly to human beings.

Induction of micronucleus of Oreochromis niloticus exposed to waters from the Cubatão do Sul River, southern Brazil

In an effort to characterize the pollution of surface waters by potentially genotoxic agents, this study aimed at assessing the frequency of micronucleated (MN) erythrocytes of the fish species, Oreochromis niloticus, from the Cubatão do Sul River. This river is the source of drinking water for the region of Florianópolis, capital of Santa Catarina State, Brazil. Negative control fish showed low frequency of MN, ranging between 0.49‰ and 0.90‰. Positive control (potassium dichromate 2.5 mg/L) organisms showed high MN frequency (16.82-17.25‰). The MN frequency increased along the river (Site 1--1.24‰ winter 2011; Site 4--9.76‰ summer 2011). Based on the observation of elevated MN erythrocytes frequency in O. niloticus exposed to water samples from along the river course, we conclude that the complex environmental mixtures of water from the Cubatão do Sul River have genotoxic potential. This genotoxicity most likely originated from agricultural runoff and domestic effluents released without treatment, based on the evidence from literature data and a survey in the region. This study provides a scientific basis for future studies regarding the genotoxicity of complex environmental mixtures in natural environments.