Detection of micronucleus and abnormal nucleus in erythrocytes from the gill and kidney of Labeo bata cultivated in sewage-fed fish farms

Functional characterization of Labeo rohita muscle cell line for in vitro research

BACKGROUND

Labeo rohita represents the most dominant fish species in Indian aquaculture and the fish cell lines have been used as an excellent in vitro platform for performing various biological research.

METHODS AND RESULTS

The LRM cell culture developed from the muscle tissue of L. rohita was used to study the in vitro applications. The developed muscle cells were maintained in a Leibovitz's-15 (L-15) supplemented with 10% FBS (Fetal Bovine Serum) and 10 ng/ml bFGF at 28 ^oC temperature. The LRM cells showed fibroblastic-like morphology and was authenticated by sequencing mitochondrial gene 16S rRNA. The expression of myogenic regulatory factors (MRFs) was studied in different stages of LRM cells; however, the expression patterns varied at different passages. The MEF2A, Mrf-4, and Myogenin expressions were higher in passage 25, while the expression of MyoD was maximum in passage 15, and the expression of Myf-5 was highest in passage 1. The transfection efficiency of LRM cells revealed 14 % of the GFP expression with a pmaxGFP vector DNA. The LRM cells were susceptible to the extracellular products prepared from Aeromonas hydrophilla and Edwardsiella tarda. The acute cytotoxicity of six heavy metals (Hg, Cd, Zn, Cu, Pb, Ni) was assessed in LRM cells by a dose-dependent manner in comparison to IC₅₀ values obtained from MTT and NR assays. A revival rate of 70-75% was achieved when the LRM cells were cryopreserved at - 196 °C using liquid nitrogen.

CONCLUSION

The developed muscle cells serve as an functional in vitro tool for toxicological and biotechnological studies.

Genotoxic, biochemical and histological biomarkers of subacute concentrations of paraquat and glyphosate in Nile Tilapia

The use of herbicides for increased food production may pose risk to non-target organisms. This study evaluated the acute toxicity, genotoxic, biochemical, and histological biomarkers of subacute concentrations of paraquat and glyphosate in Oreochromis niloticus (Nile Tilapia) for 28 days following standard methods. Glyphosate (96 hLC50 value-1.23 mg/L) was 9x more toxic than paraquat (96 hLC50 value-11.20 mg/L) against O. niloticus. Average micronucleated cells were significantly higher in the erythrocytes of O. niloticus exposed to the higher (1.12 mg/L) concentration of paraquat at day 14, both subacute concentrations of paraquat at day 28, and lower concentration (0.01 mg/L) of glyphosate at days 14 and 28 compared to the other treatments and controls. Biochemical biomarkers (MDA and GST) activities were significantly higher at both subacute concentrations of the herbicides in the exposed fish compared to the controls at day 28 only. GSH activity was significantly higher in the 0.11 mg/L paraquat concentration while SOD activity was significantly lower at both subacute concentrations of glyphosate in exposed fish compared to controls at day 28. Histological alterations observed were mild to severe shortening of the gill primary lamellar and hepatic portal inflammation of exposed fish compared to the controls. This study demonstrates the risk to non-target organisms due to herbicides’ run-off from agricultural farmlands into aquatic ecosystems at environmentally relevant or subacute concentrations. Sensitization on the responsible use of pesticides is recommended to promote responsible consumption and production and sustain life below water (United Nations Sustainable Development Goals 12 and 14 respectively).

Reproductive Toxicity and Recovery Associated With 4-Non-ylphenol Exposure in Juvenile African Catfish (Clarias garepinus)

Although, the effects of 4-non-ylphenol (4-NP) on fish's reproductive hormones were assessed in several studies using adult models, however, the effect of this endocrine disruptor on immature fish's reproductive hormones was not addressed commonly. We aimed to study the apoptosis induction, hematotoxicity, reproductive toxicity, and the recovery associated with 4-NP exposure in juvenile African catfish [Clarias garepinus) using some hormones [17β-estradiol (E2), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)] and gonad histology as biomarkers. The toxic effects of 4-NP have been studied in many animal models, but there is still limited knowledge about the dose-dependent damage caused by 4-NP exposure in juvenile Clarias gariepinus. A healthy juvenile C. gariepinus was categorized into four groups (n = 3/group; three replicates in each group). The first group was the control, and the other three groups were subjected to 4-NP concentrations as 0.1, 0.2, and 0.3 mg/L for 15 days; they were left for a recovery period of another 15 days. The reproductive hormones of C. gariepinus exposed to 4-NP for 15 days exhibited significant variations between the treatment groups and the control (P < 0.05), which were evident in E2 and T-values, whereas FSH, LH, total protein, and lipid peroxidation values showed non-significant differences among all groups at P < 0.05. Such a situation referred to the fact that the 15-day recovery period was insufficient to remove the impacts of 4-NP doses in concern. The trend of dose-dependent increase/decrease was recorded for T, E2, FSH, and LH. The histopathological alterations of 4-NP treated in gonad tissues were recorded in juvenile C. gariepinus, reflecting their sensitivity to 4-NP estrogenic-like effects. Overall, our results investigate that recovery has improved the reproductive toxicity caused by 4-NP in juvenile C. garepinus. Significant variations between the treated groups and the control group (P < 0.05) were evident in hematological parameters except for hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The parameters exhibiting significance decreased with such increased doses [red blood cells (RBCs), hematocrit (Hct), and white blood cells (WBCs)]. Similar patterns of significant variations toward the increase or decrease were recorded following the 15-day recovery period. Apoptotic frequency in erythrocytes and brain cells has increased significantly with increased 4-NP exposure, indicating that 4-NP caused cytotoxic effects, such as apoptosis in a dose-dependent manner. However, these cellular alterations greatly decreased after the 15-day recovery period.

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.

Blood Biochemical and Erythrocytic Morpho-pathological Consequences of Naphthalene Intoxication in Indian Teleost, Anabas testudineus (Bloch)

Anabas testudineus (Bloch) was exposed to 0.71 mg/L and 1.42 mg/L (25 and 50% of LC₅₀ value respectively) naphthalene, a polycyclic aromatic hydrocarbon (PAH), for 21 days. Blood biochemical parameters and erythrocytic morphological alterations were assessed to describe the naphthalene toxicity. Biochemical analysis showed a significant increase in glutamic pyruvic transaminase, GPT (576.7 ± 11.79 and 608.9 ± 12.08 U/L, respectively) and alkaline phosphatase, ALP (12.9 ± 0.69 and 13.4 ± 0.64 U/L, respectively) activities under two doses compared with control. Protein and albumin (ALB) content in blood decreased significantly, in comparison with control value in the tune of 22.67 ± 1.04 and 23.97 ± 1.24 g/dl, respectively and 10.7 ± 0.79 and 11.1 ± 0.67 g/dl, respectively. Erythrocytes showed varied symptomatic morphological changes under naphthalene exposure, which included severe denaturation, swelling in cells, appearance of sickle and tear drop cells, and cellular vacuolation. In particularly, the changes were more prominent under higher naphthalene exposure. Following the results, it has been able to establish that GPT, ALP, protein and ALB, and the morphological manifestations of erythrocytes would be good tools of biomarker in monitoring toxicological paradigm, especially to naphthalene exposure in aquatic bodies.

Dose-specific biochemical and erythrocytic alterations of anthracene exposure on blood of Anabas testudineus (Bloch)

The present work is designed to compare the chronic toxicity of anthracene [one of the major constituents of polycyclic aromatic hydrocarbons (PAHs)] on Anabas testudineus (Bloch), in an air-breathing carnivorous fish, in laboratory condition under the exposure of two doses of LC₅₀ value, i.e., 0.0075 mg/l (T1), i.e., 25% and 0.015 mg/l (T2) i.e., 50% for 21 days. A comprehensive comparison was recorded based on biochemical parameters and evaluated the erythrocytic alterations of blood components of the fish. It revealed an enhanced trend of activity of glutamic pyruvic transamin (GPT) 470.7 ± 12.32, 546.6 ± 13.22, 599.4 ± 13.09 U/L and alkaline phosphatase (ALP) 9.2 ± 0.61, 10.4 ± 0.86, 10.9 ± 0.74 U/L in control, T1 and T2 respectively; and reverse trend of protein (PRO) 26.63 ± 1.32, 22.15 ± 1.13, 22.29 ± 1.02 g/dl and albumin (ALB) 11.9 ± 0.71, 9.65 ± 0.91, 10.05 ± 0.94 g/dl in control, T1 and T2 respectively. Under T1 and T2 exposure conditions, it displayed the maximum alterations and appearance of tear drop-like cells (Tr), sickle cells (Sk), swelled cells (Sc) and vacuolated cells (Va) in comparison to control condition. An exclusive experimentation of the present work suggested that biochemical parameters and erythrocytic alterations may be useful tool as biomarkers to monitor the long term toxicological effects, especially to anthracene a constituent of PAHs, in any aquatic environment.

Changes in Blood Cell Morphology and Number of Red Spotted Grouper, Epinephelus akaara in Response to Thermal Stress

Rising of water temperature due to global warming is a great concern to aquaculturists and fishery biologists. Hence, the present study aimed to investigate the effects of high water temperature on juvenile red spotted grouper, Epinephelus akaara based on the evaluation of stress responses in blood. E. akaara juveniles were exposed to different thermal conditions (25℃, 28℃, 31℃, and 34℃) for 6 weeks following 2 weeks of acclimation at 25℃. Blood cell morphology and number were examined at three sampling points (2, 7, and 42 days) from a total of 180 fish. Major erythrocytic cellular abnormalities (ECA) observed in blood smears of thermally stressed groups (31℃ and 34℃) after 6 weeks were echinocytes, teardrop-like cells, swollen cells and vacuolated cells. Both red and white blood cell number (RBC and WBC) were significantly (p<0.05) elevated in 31℃ and 34℃ group after 6 weeks thermal exposure. Differential leucocytes number showed significant increases in neutrophil (N) and decreases in lymphocytes (L) in the highest temperature (34℃). Different N:L ratio was observed at different thermal conditions which can be used as a reliable alternative to measure stress response. Taken together, these results suggest that higher temperature (31℃ and 34℃) can interfere the immune system of red spotted grouper by altering the blood cell morphology and number.

Sensitivity of medaka (Oryzias latipes) to 4-nonylphenol subacute exposure; erythrocyte alterations and apoptosis

The present study was undertaken to assess the effects of the endocrine-disrupting compound; 4-nonylphenol (4-NP) in medaka (Oryzias latipes). The frequencies of erythrocyte alterations, apoptosis, and micronuclei were used as biological indicators of damage. Medaka were exposed 15 days to 4-NP at three sublethal concentrations (50, 80, and 100 μg/l 4-NP) and results compared with those of a previous study using catfish as an animal model. Exposure of medaka resulted in a dose-dependent increase in the frequency of erythrocyte alterations, apoptosis and micronucleus (MN). Many morphological alterations and nuclear abnormalities were observed, including acanthocytes, lobed nucleus, eccentric nucleus, fragmented nucleus, blebbed nucleus, binuclei, deformed nucleus, notched nucleus, hemolysed cells, crenated cells, teardrop-like cells, and schistocytes. Mortality was recorded after treatment with 80 and 100 μg/l 4-NP, indicating that medaka are more sensitive than catfish to 4-NP exposure. We concluded that, 4-NP causes several malformations in the shape and number of erythrocytes in medaka, indicating its genotoxicity.

Multivariate and integrative approach to analyze multiple biomarkers in ecotoxicology: A field study in Neotropical region

Aquatic pollution has dramatically worsened in developing countries, due to the discharge of a mixture of pollutants into water bodies, to the lack of stringent laws, and the inadequate treatment of effluents. In this study, the Neotropical fish Astyanax aff. paranae was sampled from three sites with different pollution levels: 1) a Biological Reserve (Rebio), protected by the Brazilian government; 2) an agricultural area in one of the most productive regions of Brazil, upstream of an urban zone; and 3) a site downstream from urban zone, characterized by the influx of different effluents, including wastes from industry, a sewer treatment plant, and agricultural areas. We assess biomarkers at multiple levels, such as the comet assay, hepatic histopathological analysis, brain and muscle acetylcholinesterase (AChE) and the hepatic enzymes glutathione-S-transferase (GST), catalase (CAT), and lipoperoxidation (LPO), during winter and summer. The interpretation of field results is always a very complex operation, since many factors can influence the variables analyzed in uncontrollable conditions. For this reason, we apply an integrative multivariate analysis. The results showed that the environmental risk of the three sites was significantly different. We can see a gradient in data distribution in discriminant analysis: separating, from one side, the fish of Rebio; in the middle are the fish from agricultural area and, in the other side are the animals from downstream site. Overall, the biomarkers responses were more greatly altered in the downstream site, whereas fish from the agricultural area showed an intermediate level of damage. The greatest changes were likely caused by agriculture, industrial chemical effluents and ineffective sewage treatments, in a synergic interaction in downstream site. In conclusion, the use of multiple biomarkers at different response levels to assess the toxic effects of mixed pollutants in a natural aquatic environment is an important tool for monitoring polluted regions.

Hexavalent Chromium Reduction from Pollutant Samples by Achromobacter xylosoxidans SHB 204 and its Kinetics Study

Cr(VI) is most toxic heavy metal and second most widespread hazardous metal compound worldwide. Present work focused on Cr(VI) reduction from synthetic solutions and polluted samples by Achromobacter xylosoxidans SHB 204. It could tolerate Cr(VI) up to 1600 ppm and reduce 500 ppm with 4.5 chromium reductase enzyme units (U) having protein size 30 kDa. Changes in morphology of cells on interaction with Cr(VI) metal ion was also studied using SEM-EDX and FTIR. Microcosm studies in pollutant samples for Cr(VI) reduction and adsorption isotherm with biomass of bacterium was best fitted with Langmuir model along with kinetic studies. This study focuses on significance of Cr reduction from synthetic solutions and polluted samples by A. xylosoxidans SHB 204 and its potential for bioremediation.

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.

Sewage pollution: genotoxicity assessment and phytoremediation of nutrients excess with Hydrocotyle ranunculoides

The discharge of sewage effluents into low-order streams has negative effects on water quality. Macrophytes can be efficient in the treatment of this wastewater due to the removal of the main pollutants. The genotoxicity of sewage-polluted water discharging into La Choza stream was evaluated by testing with Allium cepa. Also, a phytoremediation assay with continuous recirculation of the residual water was conducted for 12 days. Three treatments were carried out. One treatment (Hr) was performed with a macrophyte (Hydrocotyle ranunculoides), and two treatments were conducted without macrophytes: with lighting (Ai) and without lighting (Ao). The wastewater was toxic according to all the evaluated indexes (mitotic index, frequency of chromosomal aberrations and micronucleus). High concentrations of ammonium, dissolved inorganic nitrogen (DIN), total (TP) and soluble reactive phosphorous (SRP) and indicators of faecal contamination were determined in the wastewater. The ammonium, DIN, SRP and TP loads at the end of the assay were significantly lower in the treatments with light (Hr and Ai). So, the nutrient removal was due to their absorption and adsorption by the periphyton and H. ranunculoides. Our results lead us to recommend the maintenance and planting of macrophytes in lowland streams subject to sewage pollution.

Antioxidant and in vivo genoprotective effects of phenolic compounds identified from an endophytic Cladosporium velox and their relationship with its host plant Tinospora cordifolia

ETHNOPHARMACOLOGICAL RELEVANCE

Tinospora cordifolia (Willd. Hook. f. & Thomson; family: Menispermaceae), has a long history of use in various traditional medicinal systems including "Ayurveda". It is reported to possess anticancer, antidiabetic, antimicrobial, antispasmodic, and antiinflammatory activities. T. cordifolia has also been well documented for production of various bioactive metabolites and their antioxidant activity, but the microorganisms associated with it have been least explored for the same properties.

AIM OF THE STUDY

Aim of the present study was to evaluate antioxidant and in vivo genoprotective potential of phenolic compounds produced by an endophytic fungus Cladosporium velox TN-9S isolated from T. cordifolia.

MATERIALS AND METHODS

The isolate of C. velox TN-9S was cultivated in malt extract medium and extracted with ethyl acetate. Total phenol content was determined by Folin Ciocalteu reagent. The antioxidant activity was measured in terms of DPPH and FRAP assay. The in vivo genoprotective activity was assessed using fish Channa punctatus as model. Identification of phenolic compounds was carried out using RP-HPLC. The fungal extract was evaluated for biosafety using Salmonella typhimurium His^- strain and CHO cell lines for mutagenicity and cytotoxicity, respectively.

RESULTS

The total phenolic content in the ethyl acetate extract of the fungus was determined to be 730μg gallic acid equivalent/mL. The extract evinced significant antioxidant activity with IC₅₀ value of 22.5µg/mL in DPPH scavenging assay. The phenolic extract showed good in vivo genoprotective activity against the genetic damage induced in fish C. punctatus after treatment with a non-ionic surfactant 4-nonylphenol. RP-HPLC analysis revealed the presence of peaks corresponding to various phenolic compounds in the extract. Mutagenicity and cytotoxicity results revealed the extract to be nonmutagenic and non cytotoxic in nature.

CONCLUSION

The results indicate the potential of an endophytic C. velox isolated from T. cordifolia as a producer of phenolic compounds with antioxidant and genoprotective activities which could be exploited in pharmaceutical industry. The ability of endophytes to produce similar compounds as the host, is also revealed in the present study.

Sublethal effects of pulp and paper mill effluent on two commonly cultured carps: a SEM- and EDS-based hematological biomarker analysis

Blood being a vehicle for the transport of industrial pollutants in living system, fish hematology is considered as potent biomarker. In the present study, we investigated respective sublethal effects of pulp and paper mill effluents on hematology of two commonly cultured carps, Cyprinus carpio and Ctenopharyngodon idella, using optical, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Irrespective of species, results showed significant decrease in erythrocyte, hematocrit and hemoglobin contents while an increase in white blood cell counts (P < 0.05). We observed an increasing trend of MCV (170.0 ± 3.07 to 193.16 ± 2.5) and MCH (34.31 ± 1.89 to 38.71 ± 3.61) up to 28th day in C. carpio (P < 0.05), while, in C. idella, the highest percent increase in MCV (180.8 ± 2.19) and MCH (32.9 ± 0.62) was observed on seventh exposure day, which subsequently declined, respectively, to 173.1 ± 17.1 and 27.9 ± 2.45 on 28th day. Unlike C. carpio, significant and progressive MCHC declining trend (18.23 ± 0.28 to 16.13 ± 0.31) was observed in C. idella. The most commonly observed abnormalities under SEM include echinocytes, cytoplasmic blebbing, cytoplasmic ring, spherocytes, lobopodial projections and acanthocytes in red blood cells of exposed fishes. EDS further revealed the presence of aluminum, antimony, arsenic, cadmium, mercury, tungsten, zinc and titanium; some of these metals were not even detected in the effluent samples, suggesting the probable metal bio-concentration in fish tissue, and subsequent jeopardization is a major concern particularly in the industrial area. Our study further suggested the use of sensitive and specific techniques like SEM and EDS in fish hematological biomarker analysis along with the conventional approach.

Integrated biomarker response in catfish Hypostomus ancistroides by multivariate analysis in the Pirapó River, southern Brazil

Aquatic pollutants produce multiple consequences in organisms, populations, communities and ecosystems, affecting the function of organs, reproductive state, population size, species survival and even biodiversity. In order to monitor the health of aquatic organisms, biomarkers have been used as effective tools in environmental risk assessment. The aim of this study is to evaluate, through a multivariate and integrative analysis, the response of the native species Hypostomus ancistroides over a pollution gradient in the main water supply body of northwestern Paraná state (Brazil). The condition factor, micronucleus test and erythrocyte nuclear abnormalities (ENA), comet assay, measurement of the cerebral and muscular enzyme acetylcholinesterase (AChE), and histopathological analysis of liver and gill were evaluated in fishes from three sites of the Pirapó River during the dry and rainy seasons. The multivariate general result showed that the interaction between the seasons and the sites was significant: there are variations in the rates of alterations in the biological parameters, depending on the time of year researched at each site. In general, the best results were observed for the site nearest the spring, and alterations in the parameters at the intermediate and downstream sites. In sum, the results of this study showed the necessity of a multivariate analysis, evaluating several biological parameters, to obtain an integrated response to the effects of the environmental pollutants on the organisms.

Sewage sludge hazardous assessment: chemical evaluation and cytological effects in CHO-k1 cells

Application of sewage sludge in agricultural lands is a growing practice in several countries due to its numerous benefits to soil and crops, where chemical and pathogen levels are determined by corresponding legislation. However, the presence of contaminants in residues must always be controlled before application due to their dangerous effects over the ecosystem and potential risks to human health. The main objective of this study was to integrate biological and chemical analysis in order to help elucidating the residue potential toxic, cytotoxic, and mutagenic effects. We evaluate samples of sewage sludge before and after the sanitizing treatment with lime in cytokinesis-block assay using CHO-k1 culture cells. The sanitizing treatment promoted a decrease in pathogen levels, which is the main purpose of this process. Even with chemical levels below the established by environmental agencies, results showed sewage sludge ability to enhance genotoxic and mutagenic effects, proving that residue should be handled with caution in order to minimize its environmental and human risk.

Impact of treated wastewater on organismic biosensors at various levels of biological organization

Relating the treated wastewater quality and its impact on organismic biosensors (Prussian carp, Carassius gibelio and earthworm, Eisenia fetida) was the main objective of the study. The impact on health status of fish living downstream, microbiological contamination and antimicrobial resistance, fish tissue structure, blood biochemistry, oxidative stress, genotoxic effects, as well as multixenobiotic resistance mechanism (MXR) was assessed. Treated wastewater discharged from the WWTP modified the environmental parameters and xenobiotic concentrations of the receiving surface waters. Potential bacterial pathogens from fish and respective waters were found in relatively low numbers, although they comprised aeromonads with a zoonotic potential. High resistance profiles were determined towards the tested antimicrobial compounds, mostly sulfamethoxazole and erythromycin. Histopathology primarily revealed gill lamellar fusion and reduction of interlamellar spaces of effluent fish. A significant increase in plasma values of urea, total proteins, albumins and triglycerides and a significant decrease in the activity of plasma superoxide dismutase were noted in carp from the effluent-receiving canal. Micronucleus test did not reveal significant differences between the examined groups, but a higher frequency of erythrocyte nuclear abnormalities was found in fish sampled from the effluent-receiving canal. Earthworms indicated to the presence of MXR inhibitors in water and sludge samples, thus proving as a sensitive sentinel organism for environmental pollutants. The integrative approach of this study could serve as a guiding principle in conducting evaluations of the aquatic habitat health in complex bio-monitoring studies.

Sewage-fed aquaculture: a sustainable approach for wastewater treatment and reuse

This study assesses the long-term sustainability for operation and maintenance (O&M) of sewage-fed aquaculture-based sewage treatment system. The study focused on the integrated assessment of an engineered pond system of 8 million liters per day capacity in the city of Karnal, the State of Haryana, northern India. Major areas during the assessment included health, environmental, societal and institutional views aspects as well as the quality of treated effluent subjected for reuse. The treatment facility met the Indian regulatory standards (downstream reuse and discharge into the legally permitted water bodies) in terms of physical-chemical parameters. The total coliform and faecal coliform removal were up to 2-3 log units; nevertheless, it was not capable to come across the bacterial count requirement (<1,000 per 100 mL to minimise human health risk in aquaculture practices). The system was able to generate sufficient net income required for routine O&M. Annual revenue collected by the Municipal Corporation from the lease of the facility as well as selling of treated wastewater was $3,077 and $16,667-$25,000, respectively. The additional benefit from the facility for the farmers included the saving of fertilizers and cheapest source of water available for irrigation. Recycling of treated sewages for irrigation is also returned nutrients to the surrounding farms in Karnal. This exercise has saved significant quantities of chemical fertilizer (26-41 Ton of nitrogen, 10-18 Ton of phosphorous and 38-58 Ton of potassium per year) and the overall benefit for farmers during cultivation of one acre of crop was calculated to be approximately $133 per year.

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.

In vitro cytotoxicity assessment of two heavy metal salts in a fish cell line (RF)

Labeo rohita (rohu) is one of most important of Indian major carps, which is highly ranked among the important freshwater aquaculture species in the world. Heavy metals are major risk factors for aquatic health, which are biomagnified through the food chain. The present study was carried out to investigate the effect of different divalent salts of two heavy metals, such as zinc (ZnCl(2), ZnSO(4) and ZnNO(3)) and cadmium (CdCl(2) and CdSO(4)), in an established fish cell line, RF developed from fin tissue of L. rohita. The RF cell line was used for assessment of heavy metal cytotoxicity through various endpoint assays, including maximum tolerated dose (MTD) determination, 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, neutral red (NR) uptake assay, and Coomassie brilliant blue (CBB) assay. Results revealed that these heavy metal salts were cytotoxic to the RF cell line at varied concentrations. MTD values were found to be 1.563, 3.125, 6.25, 12.5 and 25 mg/L for CdCl(2), CdSO(4), ZnCl(2), Zn(NO(3))(2) and ZnSO(4), respectively. The half-maximal inhibitory concentration values calculated by MTT, NR and CB assay were 53.83 ± 7.02, 58.03 ± 9.12 and 79.20 ± 15.27 for ZnSO(4), 26.44 ± 7.01, 36.60 ± 7.82 and 155.6 ± 14.75 for Zn(NO(3))(2), 20.26 ± 17.95, 16.94 ± 7.05 and 87.54 ± 7.58 for ZnCl(2), 5.166 ± 0.57, 15 ± 1 and 41.80 ± 8.38 for CdSO(4) and 4.966 ± 0.56, 9.56 ± 1.73 and 20.93 ± 4.47 for CdCl(2). This study establishes the RF cell line as an in vitro tool for assessment and monitoring of heavy metal concentration in the aquatic environment.

Resource recovery from septic tank effluent using duckweed-based tilapia aquaculture

Two parallel duckweed ponds were deployed to utilize nutrients from the effluent of a septic tank treating domestic wastewater. The effluent and fresh biomass of duckweed pond were fed to two subsequent fish ponds stocked with Nile tilapia (Oreochromis niloticus). Fish ponds receiving freshwater and commercial feed were used as control. The results of specific growth rate and feed conversion ratio showed no significant difference between the control ponds and treatment ponds. On the other hand, the total and net fish yields were significantly higher in the control. Microbial analysis revealed contamination of gills, intestine and liver of fish in the treatment ponds. The activity of the immune response genes was up-regulated in the brain and liver of the treatment samples. A micronucleus assay revealed a similar percentage of micronuclei in the polychromatic erythrocytes of blood in the control and treatment samples, while the treatment samples a had higher incidence of micronuclei in the polychromatic erythrocytes of gills, compared with the control.

Chemical and toxicological characterization of the bricks produced from clay/sewage sludge mixture

The present study aimed to characterize chemical properties of clay bricks containing 20 % of sewage sludge. After detection of potentially hazardous metals, we simulated precipitation exposure of such material to determine the amount of heavy metals that could leach out of the bricks. Metals, such as copper, zinc, nickel, cobalt, chromium, etc., were detected in leachate in low concentrations. Moreover, human peripheral blood lymphocytes were exposed to brick leachate for 24 h in order to evaluate its possible negative impact on human cells and genome in vitro. Cytotoxicity tests showed no effect on human peripheral blood lymphocytes viability after exposure to brick's leachate. On the contrary, the alkaline comet assay showed slight but significant increase in DNA damage with all three parameters tested. As we might predict, interactions of several heavy metals in low concentrations could be responsible for DNA damaging effect. In that manner, our findings suggest that leachates from sewage sludge-produced bricks may lead to adverse effects on the exposed human population, and that more stabile bricks should be developed to minimize leaching of heavy metals into the environment. Bricks with lower percentage of the sludge may be one of the solutions to reduce the toxic effect of the final product.

Effects of 4-nonylphenol on blood cells of the African catfish Clarias gariepinus (Burchell, 1822)

In the present work, the destructive effects of the 4-nonylphenol on one of the most economically important Nile fishes, namely African catfish (Clarias gariepinus) were studied. Apoptosis, erythrocytes alterations, micronucleus test and blood parameters count were used as biological indicators to detect those effects. After exposure to sublethal concentrations of 4-nonylphenol (0, 0.05, 0.08 and 0.1mg/l), apoptotic red blood cells with many malformations and micronucleated erythrocytes were recorded. Decrease in the blood parameters such as red blood cells (RBCs), hemoglobin (Hb), package cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC), platelets, white blood cells (WBCs), lymphocytes, basophils, monocytes and increase in mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), neutrophils, eosinophils indicated the negative effects of 4-nonylphenol. It was concluded that, the 4-nonylphenol caused genotoxicity in erythrocytes with many malformations in shape and number indicated with other blood parameters.

Giemsa versus acridine orange staining in the fish micronucleus assay and validation for use in water quality monitoring

This study concerns a comparative analysis of the acridine orange and Giemsa staining procedures for the fish erythrocyte micronucleus assay. The goal was to optimize the assay in the context of field water monitoring. Fish (Carassius carassius) were exposed to a reference genotoxic agent, cyclophosphamide monohydrate 5 mg l(-1) for 2, 4, and 6 days before testing. Slides from each individual were scored using the two procedures. The results show that the assay was more sensitive when acridine orange was used. When slides were Giemsa stained, the presence of ambiguous artefacts, leading to false positives and increasing random variance, reduced the contrast between exposed and control samples. Acridine Orange staining was then applied in the context of water quality monitoring. Fish were exposed for 4 days to water sampled in two hydrological contexts: basal flow and spring flood. The results show that exposure to spring flood water in an agricultural stream can induce mutagenicity.

Sublethal exposure of heavy metals induces micronuclei in fish, Channa punctata

Present studies were designed to evaluate toxic potential of three common heavy metals, adequately present in agro-industrial effluents, viz. mercury, arsenic and copper using in vivo micronucleus assay in an actinopterygiian fish, Channa punctata (2n=32). Ten days laboratory acclimatized fishes were divided into five groups. Groups I and II served as negative and positive controls, respectively and fishes of group III-V were subjected uninterrupted to sublethal concentrations (10% of 96 h LC50) of heavy metal compounds, HgCl2 (0.081 mg L(-1)), As2O3 (6.936 mg L(-1)) and CuSO(4).5H2O (0.407 mg L(-1)) for 24, 48, 72, 96 and 168 h of exposure periods. Significant increase over and above negative control in the frequency of micronuclei was observed in fishes exposed to metal compounds. The average frequency of micronuclei in fishes exposed to Hg(II), As(III) and Cu(II) observed was 9.79, 12.03 and 8.86, respectively. It reveals that the order of induction of micronuclei frequency and toxicity was As>Hg>Cu. Findings depict genotoxic potential of these metal compounds even in sublethal concentrations.

Genotoxic effects of binary mixtures of xenoandrogens (tributyltin, triphenyltin) and a xenoestrogen (ethinylestradiol) in a partial life-cycle test with Zebrafish (Danio rerio)

A partial life-cycle test with the model fish Danio rerio was performed in order to evaluate the genotoxic potential of binary mixtures of xenoandrogenic (tributyltin--TBT; triphenyltin--TPT) and an estrogenic compound (ethinylestradiol--EE2). Five days post-fertilisation larvae were diet-exposed to environmental relevant concentrations of TBT and TPT (25 ng/g-100 ng/g), and water-exposed to ethinylestradiol (3.5 ng/L) for a four-month period; binary mixtures of TBT plus EE2 and TPT plus EE2 were run in parallel. The erythrocytic nuclear abnormalities (ENA) assay in circulating erythrocytes was used to evaluate genotoxicity in the end of the four-month exposure period. A significant increase (p<0.05, Kruskall-Wallis non-parametric ANOVA) in ENA frequency, in comparison with control animals, was observed in those animals exposed to TBT and TPT (the highest doses only), and to EE2 and the binary mixtures, although neither synergistic nor additive effects of the tested compounds were evident. Overall, the results clearly indicate that chronic exposure to low levels of TBT, TPT, EE2 and binary mixtures of TBT plus EE2 and TPT plus EE2 are genotoxic to zebrafish, which may suggest that wild fish populations may be under increased DNA damage in areas contaminated by these endocrine disrupting chemicals.