Environmental genotoxicity and cytotoxicity levels in fish from the North Sea offshore region and Atlantic coastal waters

Combined use of ecotoxicity tools and physicochemical analysis for evaluating potential toxicity of treated natural rubber processing effluents and receiving waters

Potential toxicity of treated effluents of selected natural rubber processing industries was evaluated by integrating physicochemical analysis with Daphnia magna and Poecilia reticulata bioassays as ecotoxicity tools. Further, the efficacy of the constructed wetland treatments practiced by the industries for reducing the ecotoxicity of the final effluents reaching the receiving water course was assessed. Even after passing through the constructed wetlands, some of the measured physicochemical parameters of the final effluents did not comply with the stipulated rubber processing effluent regulatory limits. Acute toxicity data of treated effluents demonstrated greater susceptibility of D. magna compared to P. reticulata. Erythrocytic abnormality tests with P. reticulata revealed that rubber industry effluents contained cytogenotoxic contaminations which had not been completely eliminated by the treatment processes. Wetland treatment technique was not effective in reducing the cytogenotoxic effects of final effluents reaching the receiving water course. The use of ecotoxicity tools for optimization of rubber industry effluent treatment processes would help to reduce potential toxic/cytogenotoxic effects of effluent receiving waterbodies considering sustainable development goals focusing on ecosystem safety.

Pollution patterns and their effects on biota within lotic and lentic freshwater ecosystems: How well contamination and response indicators correspond?

Aquatic environments are often severely polluted with chemical substances of anthropogenic origin, which can pose a potential threat to aquatic organisms and human health. In this study, patterns and sources of heavy metals (HMs, 6 metals) and polycyclic aromatic hydrocarbons (PAHs, 16 hydrocarbons), contamination indicators, environmental genotoxicity measures and metrics of ecological status in lotic and lentic ecosystems were collated for the first time. Chemical analysis has confirmed previously reported long-term contamination at certain study sites. The sediments of Lake Talkša, located in a city and characterized by exclusive anthropogenic pressure, exhibited the highest levels of contamination by both HMs and PAHs. Through positive matrix factorization (PMF) analysis, vehicle and industrial emissions were identified as the primary sources of HMs and PAHs. Our results revealed that frequencies of genotoxic aberrations were higher in river sites compared to lakes, with the highest genotoxic risk observed in the Nemunas River below industrial cities Alytus and Kaunas. Surprisingly, even the severely contaminated Lake Talkša showed only a "moderate" grade of genotoxic risk, highlighting the potential for adaptation of biota to long-term contamination especially in lentic ecosystems. The ecological quality status assessed by macroinvertebrate metrics, which may be sensitive to observed high biological contamination, appeared to be unrelated to contamination patterns. Consequently, to obtain the robust information on anthropogenic contamination and its effects, a combination of various assessment methods and metrics should be employed.

Ecogenotoxicological studies for an early toxicity screening and monitoring in Epinephalus chlorostigma and Scamberomorus commerson

The study was planned to investigate DNA fragmentation in fish to screen aquatic toxicity and in Epinephalus chlorostigma and Scamberomorus commerson collected from Red sea near Jizan, Saudi Arabia from three locations “(Corniche North park: “16.92161, 42.54631; Jizan Port: 16.874, 42.54952” N and Jizan Economic City: 17.26589, 42.34738“ ”)“ were used as a case study for the application of comet assay. The study area of the Red Sea is polluted due to anthropogenic activities and the disposal of wastes from multiple sources. Comet and micronucleus assays were used to detect genotoxicity in these fish species harvested from three sites. The concentration of Pb, Cr, Zn, Mn, Cu, Cd, Sn, and Hg was higher in the water samples collected from the polluted site compared to the non-polluted site of the Red sea. Comet assay for S. commerson showed significant (p < 0.05) genetic damage about 44.33 ± 3.03% DNA in comet tail at site S1. It was subsequently reduced to 31.71 ± 3.52% and 22.11 ± 2.52% at sites S2 and S3. E. chlorostigma also showed significant DNA in comet tail as 17.34 ± 2.19%, 11.87 ± 3.01%, and 36.41 ± 3.98% at site S1-S3, respectively. Significant (p < 0.05) DNA damage was observed in the fishes procured from non-polluted locations and upstream locations. The micronucleus induction in E. chlorostigma was recorded as 23.20 ± 4.19 and 2.20 ± 0.58%, respectively, non-polluted and polluted sites. S. commerson exhibited significant differences between polluted and non-polluted sites (44.80 ± 3.73 and 8.20 ± 2.20‰) polluted and upstream (44.80 ± 3.73 and 20.60 ± 4.02‰), respectively. A significant difference was obtained between E. chlorostigma and S. commerson for nuclear abnormalities S. commerson showed higher frequencies for nuclear deformities than E. chlorostigma. S. commerson showed substantial micronucleus induction frequencies collected from an area of low pollution intensity (upstream). This study showed that E. clorostigma and S. commerson could be successfully used as a bioindicator to determine the health of the Red Sea through the most specific assays such as comet and micronucleus tests as an early warning and to devise the monitoring strategies to ensure a safe supply of fish for human consumption.

Genotoxicity, oxidative stress, and biochemical biomarkers of exposure to green synthesized cadmium nanoparticles in Oreochromis niloticus (L.)

The considerable increment in the use of Nanoparticles in the industry has been recognized as an environmental concern today. Therefore, this study aimed to investigate the toxicity effects of green synthesized cadmium nanoparticles [Cd]^NPs using Moringa oleifera leaves extract on multi-biomarkers in Oreochromis niloticus after four weeks of exposure. The results showed that LC₅₀ values of [Cd]^NPs for 24, 48, 72 and 96 h were 2.17, 1.75, 1.49 and 1.22 mg l^-1, respectively. There was a significant decrease in the number of white and red blood cells, hemoglobin, hematocrit, mean corpuscular hemoglobin concentration value in fish exposed to [Cd]^NPs. The mean corpuscular volume and neutrophils were increased. [Cd]^NPs exposure to fish has led to cytotoxic and genotoxic changes in the erythrocytes. Significant changes were observed in the cortisol, triiodothyronine, and thyroxine levels of the fish exposed to [Cd]^NPs. The activities of aspartate aminotransferase and alanine aminotransferase increased. Glucose, total lipids, urea, and creatinine levels increased in the serum of fish exposed to [Cd]^NPs, whereas total protein contents and alkaline phosphatase activity decreased. A significant reduction was observed in glycogen, total antioxidant levels, and superoxide dismutase, catalase and glutathione S-transferase activities of fish exposed to [Cd]^NPs. In contrast, the [Cd]NPs exposure resulted in a significant increase in DNA fragmentation percentages, lipid peroxidation, and carbonyl protein levels in different tissues. The results of the present study confirmed that [Cd]^NPs has the toxicity potential to cause Cyto-genotoxicity, oxidative damages, changes in the hematological and biochemical changes, and endocrine disruptor in the fish.

Micronuclei in Fish Erythrocytes as Genotoxic Biomarkers of Water Pollution: An Overview

Freshwater and marine water bodies receive chemical contaminants from industrial, agricultural, urban, and domestic wastes. Eco-genotoxicity assays are useful tools to assess the cumulative genotoxicity of these pollutants. Fish are suitable indicators for biomonitoring of mutagenic and carcinogenic pollution.In this review, we present a complete overview of the studies performed so far using the micronucleus test in peripheral erythrocytes of fish exposed to polluted water. We have listed all the species of fish used and the geographical distribution of the investigations. We have analyzed and discussed all technical aspects of using this test in fish, as well as the advantages and disadvantages of the different experimental protocols. We have reported the results of all studies. This assay has become, for years, one of the simplest, fastest, and most cost-effective for assessing genotoxic risk in aquatic environments. However, there are still several factors influencing the variability of the results. Therefore, we have given indications and suggestions to achieve a standardization of experimental procedures and ensure uniformity of future investigations.

Heavy metal bioaccumulation, oxidative stress and genotoxicity in African catfish Clarias gariepinus from Orontes river

One of the major problems affecting the ecosystem health is the exposure of heavy metals due to anthropogenic activities. These exposures may induce toxiogenetic damage and carcinogenesis in aquatic organism. DNA damage biomarkers for fish species detect genotoxic parameters for ecological risk assessment. In the present study, the effect of heavy metals (Cr, Cd, Cu, Fe and Mn) on DNA damage and oxidative stress of Clarias gariepinus was examined by Comet assay at Reference site and two different sampling sites of the Orontes River. Moreover, the relationship between DNA damage and physiological response to oxidative stress caused in C. gariepinus was investigated by sampling seasonal water and fish samples for one year. In this study, Cr, Cd and Cu in water column of Orontes River and the concentrations of Fe and Mn in liver tissue of C. gariepinus were highly exceed the maximum permissible limit set by EPA (1999, 2016) WHO (1989) and TEG (2012) that can cause adverse effects on environment health. SOD activities in liver tissues were significantly higher than those in muscle tissues. SOD, CAT activity and MDA levels of both Site 1 and Site 2 at Orontes River were higher than those of the Reference site. In result of the COMET analysis, the highest levels of DNA damage were found at gill and liver tissues in Site 2 (17.746 ± 1.072% T-DNA; 16.014 ± 0.710% T-DNA respectively) at Orontes river. A higher level of DNA damage in gill cells compared to liver cells was observed in all regions of the Orontes River. In Principal component analysis (PCA), the heavy metals Cd, Cr and Cu (in the water column) and MDA in liver and muscle revealed strong contribution to the observed DNA damage that were scattered opposite to each other's along the principal components. Moreover, correlations between parameters revealed a positive significant relationship between Cd, Cr and Cu in water and DNA damage levels in C. gariepinus. Pearson correlation analysis detected a positive relationship between MDA, CAT and SOD and DNA damage levels in African catfish. Consequently, this study exposed genotoxic damage and oxidative stress of C. gariepinus due to metal pollution in Orontes River and lead to the better understanding of genotoxicty, oxidative stress and heavy metal relationships.

Heavy metal pollution and risk assessment by the battery of toxicity tests

The current study was carried out on dominant fish Oreochromis niloticus and water collected from the polluted Yamuna River, Agra, India. The heavy metals in water, recorded as follows: Fe > Mn > Zn > Cu > Ni > Cr > Cd and all were found to be above the prescribed limits. According to metal pollution index, exposed muscle (49.86), kidney (47.68) and liver (45.26) have been recorded to have higher bioaccumulation. The blood biochemical analysis of exposed O. niloticus indicated significant increase in activities of aspartate aminotransferase (+ 343.5%), alkaline phosphatase (+ 673.6%), alanine aminotransferase (+ 309.1%), and creatinine (+ 494.3%) over the reference. However, a significant decrease in albumin (A): globulins (G) ratio (− 87.86%) was observed. Similarly, the exposed fish also showed significant increase in total leucocyte count (+ 121%), differential leucocyte count, respiratory burst (+ 1175%), and nitric oxide synthase (+ 420%). The histological examination of liver and kidney showed tissue injury. Moreover, micronuclei (0.95%), kidney shaped nuclei (1.2%), and lobed nuclei (0.6%) along with DNA damage in the form of mean tail length in the liver (20.7 µm) and kidney (16.5 µm) was observed in the exposed O. niloticus. Potential health risk assessments based on estimated daily intake, target hazard quotient, hazard index, and target cancer risk indicated health risks associated with the consumption of these contaminated fishes. In conclusion, the present study showed that exposure to heavy metals contaminated water can alter immunological response; induce histopathological alterations and DNA damage in the studied fish. The consumption of this contaminated water or fish could have serious impact on human health.

Assessment of DNA integrity through MN bioassay of erythrocytes and histopathological changes in Wallago attu and Cirrhinus mirigala in response to freshwater pollution

The aim of this study was to determine the level of contamination and genotoxic impact through micronucleus assay and histopathology in Wallago attu and Cirrhinus mrigala procured from the polluted site of the River Chenab at industrial and sewage waste disposal. The water sample was found viciously contaminated with heavy metals i.e. Ni, Cr, Mn, Co, Pb, Hg, Zn, Sn, Cu while all other physio-chemical variables crossed the suggested limits of WHO. The heavy metals load induced histopathological alterations were correlated to environmental degradation and the productivity of this biological system. W. attu and C. mrigala harvested from contaminated sites of the river indicated higher intensity of DNA damage through micronucleus induction and nuclear abnormalities with 5.46 ± 0.17, 1.23 ± 0.08 and 4.2 ± 0.11, 0.4 ± 0.04‰ respectively. Muscle sections of W. attu and C. mrigala harvested from the polluted section of river demonstrated the necrosis, degeneration of muscle fibers, intra-fibular edema and release of the blood into the tissues due to the bursting of blocked of the blood vessels. Dermal layers showed degeneration of the collagen bundles those were found loose or collapsed in some regions. Photomicrography also revealed vacuolar degeneration in muscle tissues and atrophy of muscle bundles. Intra fibular edema and splitting of muscle fibers were also seen along with bioaccumulation of toxicants. W. attu showed maximum incidence of alterations with highest histopathological alteration index related to environmental degradation. Control fish samples showed normal muscle tissues with normal equally spaced muscle bundles and myotomes.

Genomic damage in Mugil curema (Actinopterygii: Mugilidae) reveals the effects of intense urbanization on estuaries in northeastern Brazil

The largest metropolitan centers in northeastern region of Brazil are all located near the coast, and industrial, tourist, and agro-industrial activities are the principal causes of water contamination due to discharges of untreated sewage. Adverse environmental conditions can often be detected by analyzing the genetic material of organisms exposed to pollutants, and furnish an overview of environmental quality. We evaluated possible damage to the DNA of one of the fish resources most widely consumed and commercialized by coastal communities in northeastern Brazil, Mugil curema ("tainha"). Erythrocytes from M. curema were analyzed by the presence of micronuclei and by comet assay (single cell gel electrophoresis, SCGE). Statistical comparisons to both tests revealed considerably greater genomic damage in polluted estuaries than in the control site (p < 0.05), suggesting strong genotoxic impacts on the specimens evaluated, principally among those taken near localities with dense demographic and industrial development.

Environmental genotoxicity and risk assessment in the Gulf of Riga (Baltic Sea) using fish, bivalves, and crustaceans

Environmental genotoxicity in the Gulf of Riga was assessed using different bioindicators (fish, clams, and isopods) collected from 14 study stations. Comparison of genotoxicity responses (micronuclei (MN) and nuclear buds (NB)) in blood erythrocytes of herring (Clupea harengus), eelpout (Zoarces viviparous), and flounder (Platichthys flesus) revealed the species- and site-specific differences. For the first time, the analysis of genotoxicity was carried out in gill cells of isopods Saduria entomon. The highest inductions of MN and NB in gill cells of investigated S. entomon and clams (Macoma balthica) were evaluated in specimens from station 111A (offshore zone). In fish, the highest incidences of MN were measured in eelpout and in herring collected in the southern part of Gulf of Riga (station GOR3/41S). Moreover, in the southern coastal area, the assessment of genotoxicity risk (according to micronuclei levels) indicated exceptionally high risk for flounder, eelpout, and clams.

Use of statistical analysis to validate ecogenotoxicology findings arising from various comet assay components

Cirrhinus mrigala, Labeo rohita, and Catla catla are economically important fish for human consumption in Pakistan, but industrial and sewage pollution has drastically reduced their population in the River Chenab. Statistics are an important tool to analyze and interpret comet assay results. The specific aims of the study were to determine the DNA damage in Cirrhinus mrigala, Labeo rohita, and Catla catla due to chemical pollution and to assess the validity of statistical analyses to determine the viability of the comet assay for a possible use with these freshwater fish species as a good indicator of pollution load and habitat degradation. Comet assay results indicated a significant (P < 0.05) degree of DNA fragmentation in Cirrhinus mrigala followed by Labeo rohita and Catla catla in respect to comet head diameter, comet tail length, and % DNA damage. Regression analysis and correlation matrices conducted among the parameters of the comet assay affirmed the precision and the legitimacy of the results. The present study, therefore, strongly recommends that genotoxicological studies conduct appropriate analysis of the various components of comet assays to offer better interpretation of the assay data.

Fish eco-genotoxicology: Comet and micronucleus assay in fish erythrocytes as in situ biomarker of freshwater pollution

Owing to white meat production Labeo rohita have vast economic importance, but its population has been reduced drastically in River Chenab due to pollution. Atomic absorption spectrophotometry showed a merciless toxicity level of Cd, Cu, Mn, Zn, Pb, Cr, Sn and Hg. Comet assay results indicated significant (p < .05) DNA fragmentation in Labeo rohita as 42.21 ± 2.06%, 31.26 ± 2.41% and 21.84 ± 2.21% DNA in comet tail, tail moment as 17.71 ± 1.79, 10.30 ± 1.78 and 7.81 ± 1.56, olive moment as 13.58 ± 1.306, 8.10 ± 1.04 and 5.88 ± 0.06, respectively, from three different polluted sites on the river. Micronucleus assay showed similar findings of single micronucleus induction (MN) as 50.00 ± 6.30‰, double MN 14.40 ± 2.56‰, while nuclear abnormalities (NA) were found as 150.00 ± 2.92‰. These higher frequencies of MN induction and NA were found to be the cause of reduction of 96% of the population of this fish species in an experimental area of the River Chenab. This fish species has been found near extinction through the length of the river Chenab and few specimens in rainy seasons if restored by flood, may die in sugarcane mill season. Due to sweeping extinction Labeo rohita showed the highest sensitivity for pollution and could be used as bioindicator and DNA fragmentation in this column feeder fish species as a biomarker of the pollution load in freshwater bodies.

DNA damage and cytotoxicity induced on common carp by pollutants in water from an urban reservoir. Madín reservoir, a case study

Madín Reservoir provides a substantial amount of drinking water to two municipalities close to Mexico City metropolitan area. However, it receives untreated wastewater discharges from domestic sources in the towns of Nuevo Madín and others, as well as diverse pollutants which are hauled by the Río Tlalnepantla from its upper reaches, so that the xenobiotics in the reservoir are highly diverse in terms of type and quantity. Previous studies showed that MR is contaminated with xenobiotics such as Al, Hg and Fe, as well as NSAIDs, at concentrations exceeding the limits established for aquatic life protection. These pollutants have been shown to induce oxidative stress on Cyprinus carpio and may therefore also damage the genetic material of exposed organisms, eliciting cytotoxicity as well. The present study aimed to determine the genotoxicity and cytotoxicity induced on blood, liver and gill of C. carpio by the pollutants present in MR water. Specimens were exposed to water from five sampling sites and the following biomarkers were evaluated: DNA damage by comet assay, frequency of micronuclei, apoptosis by TUNEL assay and caspase-3 activity. Significant increases relative to the control group (P < 0.05) were found with all biomarkers in all tissues evaluated, with the level of damage differing between sampling sites. In conclusion, pollutants present in MR water are genotoxic and cytotoxic to C. carpio, and this sentinel species, coupled with the biomarkers evaluated herein, is a reliable tool for assessing the health risk to wildlife posed by exposure to pollutants in freshwater bodies.

Multiple biomarker responses (serum biochemistry, oxidative stress, genotoxicity and histopathology) in Channa punctatus exposed to heavy metal loaded waste water

Experiments were conducted to investigate the health of fish Channa punctatus inhabiting heavy metal-loaded waste water. Heavy metals in the order of Fe > Mn > Zn > Co > Ni > Cu = Cr were present in the waste water. Gills had high metal load followed by liver and then kidney. Albumin, albumin to globulin (A:G) ratio, triglyceride, high density lipoprotein (HDL) and very low density lipoprotein (VLDL) were found to be lower but phospholipid, low density lipoprotein (LDL), total protein, lipid and cholesterol were higher as compared to the reference. Oxidative stress markers such as superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST) and lipid peroxidation (LPO) were significantly higher in all tissues, whereas reduced glutathione (GSH) levels were comparatively low. Damage to DNA was observed with significantly higher mean tail length of comets in the exposed fish gill cells (30.9 µm) followed by liver (24.3 µm) and kidney (20.6 µm) as compared to reference fish (5.2, 4.8 and 5.9 µm respectively). Histopathology in gill, liver and kidney also showed marked damage. Integrated biochemical, oxidative stress, genotoxicity and histopathological findings are valuable biomarkers for native fish adaptive patterns, and monitoring of water quality/pollution of freshwater ecosystems.

DNA damage in dab (Limanda limanda) and haddock (Melanogrammus aeglefinus) from European seas

Dab (Limanda limanda) and haddock (Melanogrammus aeglefinus) were collected from coastal and offshore locations in the Baltic (dab only), North Sea (haddock from one location only) and Iceland. Blood was analysed for DNA strand breaks using the comet assay and liver samples for DNA adduct concentrations. DNA strand breaks were at background levels in dab from the two Iceland locations and from the Dogger Bank. The highest levels were observed in dab from the Firth of Forth, Ekofisk and the German Bight. Hepatic DNA adducts in dab were highest at Ekofisk, in the Baltic and Dogger Bank, below detection limit in dab from Iceland and low in dab from the Firth of Forth and German Bight. There was large variation in DNA strand breaks between locations and individuals for haddock, particularly from Iceland. Adduct concentrations were elevated in haddock from both Iceland and the Firth of Forth. A general linear model (GLM) suggested that, in addition to location, the size of dab and its general condition contributed to explaining the observed variability in DNA strand breaks. A GLM for adducts in dab similarly allocated most of the variability to location, but with a possible contribution from CYP1A activity. There were no apparent differences between male and female dab for any of the methods. There was no obvious relationship between strand breaks and adducts in the same fish although dab from Ekofisk and Iceland had respectively high and low responses using both methods. The results from this large-scale study showed pollution-related genotoxicity for dab, that fish blood samples can be conserved prior to comet analyses and that there are clear species differences in genotoxic responses even when collected at the same location.

Microelectrophoretic study of environmentally induced DNA damage in fish and its use for early toxicity screening of freshwater bodies

This study investigates the potential of the comet and micronucleus assays of fish DNA as a means of screening the toxicity of aquatic environments. Catla catla and Cirrhinus mrigala collected from the River Chenab in Pakistan were used as a case study for the application of comet and micronucleus techniques. Comet and micronucleus assays were used to compare DNA damage in C. catla and C. mrigala collected from polluted areas of the River Chenab and farmed fish. Atomic absorption spectrophotometry showed an acute level of toxicity from Cd, Cu, Mn, Zn, Pb, Cr, Sn, and Hg in river water. Comet assay showed significant (p < 0.05) DNA damage in C. catla representing 17.33 ± 2.42, 11.53 ± 2.14, and 14.17% DNA in the comet tail, averaged from three sites of the polluted area of the river. Tail moment was observed as 10.06 ± 2.71, 3.11 ± 0.74, and 14.70 ± 1.89, while olive moment was 8.85 ± 1.84, 3.83 ± 0.76, and 7.11 ± 0.73, respectively. Highly significant (p < 0.01) damage was reported in C. mrigala as 37.29 ± 2.51, 34.96 ± 2.53, and 38.80 ± 2.42% DNA in comet tail, tail moment was 23.48 ± 3.90, 19.78 ± 4.26, and 14.30 ± 1.82, and olive moment was 16.22 ± 2.04, 13.83 ± 1.96, and10.99 ± 0.90. Significant (p < 0.05) differences were observed in genotoxicity between farmed and polluted area fish. Micronucleus assay showed a similar picture of significant difference in respect to single and double micronucleus induction: i.e., 23.20 ± 4.19 and 2.80 ± 1.07‰ in C. catla and 44.80 ± 3.73 and 06.20 ± 0.97‰, respectively, in C. mrigala. Nuclear abnormalities were found as 6.00 ± 0.84 and 09.60 ± 1.72/thousand cells, respectively, in both species. The results of this study suggest that these novel fish DNA damage assays can be used as an expedient toxicity screening for aquatic environments.

Erythrocyte micronucleus cytome assay of 17 wild bird species from the central Monte desert, Argentina

Birds have the potential to be considered valuable bioindicators of the quality of ecosystems and the environmental impact of pollutants. The aims of this study were to determine the micronuclei frequency and other nuclear abnormalities in erythrocytes by analyzing a wild bird community from central Monte desert (Argentina) and to clarify if there were any differences among certain species. Frequencies of nuclear abnormalities were determined in 73 wild birds belonging to 17 species and two orders (Passeriformes and Columbiformes). A high proportion of individuals, 90.4 and 80.9 %, had erythrocytes with micronuclei and nuclear buds, respectively. Notched nuclei, binucleated cells, nuclear tails, and nucleoplasmic bridges were also recorded. Certain species appeared to be more informative than others with regard to the possibility of being used as bioindicators of genetic damage. Saltator aurantiirostris and Columbina picui were the only species that showed significantly different frequencies of nuclear alterations, in comparison with the other species. The frequencies here presented are the first reported for these bird species from the orders Passeriformes and Columbiformes. This research supports the notion that the use of these biomarkers could be effectively applied to evaluate spontaneous or induced genetic instability in wild birds.

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.

Variation in genotoxic susceptibility and biomarker responses in Cirrhinus mrigala and Catla catla from different ecological niches of the Chenab River

A large number of methods have been applied to evaluate genotoxic damage in different aquatic species. Comet assay, as a method for detecting DNA alterations, and micronucleus test, as an index of chromosomal damage are the most widely used and authentic methods in laboratory and field studies. The primary objective of the study was to evaluate the genotoxic effects of heavy metals generated by toxic industrial effluents and various kinds of pollutants from urban and agricultural areas and domestic waste on Catla catla and Cirrhinus mrigala due to water pollution in the Chenab River, Pakistan. The heavy metals Cd, Cu, Mn. Zn, Pb, Cr, Sn, and Hg were detected by atomic absorption spectrophotometry from water samples collected from predetermined sampling sites. All the physicochemical parameters and heavy metals were found to exceed the upper limits recommended by various agencies. Comet assays showed significant (p < 0.05) DNA damage in C. mrigala compared to C. catla for tail length and olive tail moment from three different sites. Significant (p < 0.05) differences were reported between fish collected from polluted sites and farmed fish, but only non-significant (p > 0.05) findings were observed between fish collected from farmed and non-polluted upstream waters. Micronucleus assays showed similar findings for single and double micronucleus induction in C. catla and C. mrigala. A significantly (p < 0.05) higher micronuclei induction and percent tail DNA was observed in C. mrigala specimen collected from the polluted site. These findings infer that DNA damage could be used as a biomarker of pollution load and its early monitoring by using simple and reliable techniques such as the comet and micronucleus assays, expedient methods for toxicity screening of aquatic environments. Regular monitoring is necessary to assess eco-health of the Chenab River by choosing perhaps C. mrigala, being a bottom feeder, as a bioindicator that could provide more reliable information to determine the status of the environmental quality of the river.

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.

Early genotoxic response and accumulation induced by waterborne copper, lead, and arsenic in European seabass, Dicentrarchus labrax

Cu, Pb, and As, which are among the most abundant metals in the aquatic environment, are also among the most health-threatened by causing diverse cellular injuries. The aim of this study was to assess and compare the potential early induction of genotoxic effects after waterborne Cu, Pb, and As exposure in European seabass, Dicentrarchus labrax, a commercial widely cultured fish, using the micronucleus (MN) assay in peripheral blood erythrocytes. Fish were exposed under laboratory conditions to nominal solutions ranging 0-10 mg/L for 24 and 96 h. Furthermore, actual metal ion concentrations were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or differential pulse anodic stripping voltammetry (DPASV) in water and four fish tissues differentially related to environmental exposition and metal accumulation, i.e. the gills, liver, muscle, and brain. Dose-dependent increases of micronuclei (MNi) frequency were observed after these very short exposures; based on measured metal concentrations in water, the genotoxic effect ordered as Cu > As > Pb. Significant genotoxic effect at 0.009 mg/L Cu, 0.57 mg/L Pb, and 0.01 mg/L As was seen. For Cu and Pb these are only slightly higher, but for As it is notably lower than the USEPA criteria of maximum concentration to prevent acute toxicity in aquatic organisms. Furthermore, genotoxicity was differentially related to metal accumulation. MNi frequency correlated positively with the content of Pb in all the organs, with the content of As in liver and gills and only with the content of Cu in the brain. In conclusion, our findings raised environmental concerns because these depicted a genotoxic potential of Cu, Pb, and As after a very short exposure to low but environmentally relevant concentrations, too close to regulatory thresholds. In addition, the MN test in D. labrax could be considered an early biomarker of genotoxicity induced by these metals in fish.

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.

Genotoxicity of cadmium chloride in the marine gastropod Nerita chamaeleon using comet assay and alkaline unwinding assay

This paper presents an evaluation of the genotoxic effects of cadmium chloride (CdCl2 ) on marine gastropod, Nerita chamaeleon following the technique of comet assay and the DNA alkaline unwinding assay (DAUA). In this study, the extent of DNA damage in gill cells of N. chamaeleon was measured after in vivo exposure to four different concentrations (10, 25, 50, and 75 µg/L) of CdCl2 . In vitro exposure of hydrogen peroxide (H2 O2 ; 1, 10, 25, and 50 µM) of the gill cells showed a significant increase in the percentage tail DNA, Olive tail moment, and tail length (TL). Significant changes in percentage tail DNA by CdCl2 exposure were observed in all exposed groups of snails with respect to those in control. Exposure to 75 µg/L of CdCl2 produced significant decrease in DNA integrity as measured by DAUA at all duration with respect to control. In vivo exposure to different concentrations of CdCl2 (10, 25, 50, and 75 µg/L) to N. chamaeleon showed considerable increase in DNA damage as observed by both alkaline comet assay and the DAUA. The extent of DNA damage in marine gastropods determined by the application of alkaline comet assay and DAUA clearly indicated the genotoxic responses of marine gastropod, N. chamaeleon to a wide range of cadmium concentration in the marine environment.