96-hour LC50 Values Research Articles

Toxicological Effects of Pendimethalin: Behavioral Changes and LC50 Analysis in Cyprinus carpio

The pre-emergent herbicide pendimethalin is a selective dinitroaniline compound that interferes with the production of microtubules, potentially contaminating groundwater. The current investigation sought to ascertain the acute toxicity levels and behavioral effects of pendimethalin (30% EC) on Cyprinus carpio. Finney's probit bioassay method estimated the lethal toxicity LC50 values for commercial-grade herbicide pendimethalin on C. carpio. This method entails fitting the data collected from experiments to a probit model, which converts the results obtained (such as mortality rates) into a normal distribution scale. It is a useful tool in toxicological research since it enables more precise estimations of the LC50. The lethal toxicity (LC50) values of pendimethalin to C. carpio exposed to 24, 48, 72 and 96-hr were determined to be 2.83µL/L, 2.59µL/L, 2.39µL/L and 2.20µL/L based on the mortality estimations. Pendimethalin-induced behavioral abnormalities in C. carpio were investigated using sublethal concentrations (i.e., 1/15th, 1/10th, and 1/5th of the 96-hour LC50 value) at intervals of 0, 7, 14, 21 and 28 days. Our research observed behavioral shifts such as reduced general activity, reduced foraging behavior, diminished schooling behavior, reduced reflex stimuli, increased opercula movements, irregular movements, mucus secretion, enhanced breathing rates and increased surface air gulping. Our studies showed that pendimethalin can produce both mortality and behavioral alterations in Cyprinus carpio, offering important insights into the pendimethalin fatal and sub-lethal effects. These results highlight how crucial it is to keep an eye on herbicide poisoning in aquatic habitats since even sub-lethal levels can have an effect on fish behavior and the general health of the ecosystem.

Toxicodynamics of cadmium in the green mussel Perna viridis (Linnaeus, 1758) using bioenergetic and physiological biomarkers.

This study evaluated the toxicity of cadmium (Cd) on the green mussel Perna viridis, aiming to identify toxicological endpoints and investigate its responses across physiological, bioenergetic, and biochemical parameters. The 96-hour LC50 value for Cd in P. viridis was 3.03 ± 0.12 mg L-1, with a 95% confidence interval of 2.35-3.91 mg L-1. Chronic toxicity tests revealed a No Observable Effect Concentration (NOEC), Lowest Observable Effect Concentration (LOEC), and chronic toxicity values of 0.20, 0.37, and 0.29 mg L-1, respectively. Cadmium accumulation in treated mussels increased 46- to 215-fold compared to the control group. Superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase levels in exposed mussels exhibited a significant increase compared to the control group. The redox index ratio, acetylcholinesterase activity, and lysosomal membrane stability decreased with increasing exposure concentrations. Levels of reduced and oxidized glutathione, glutathione reductase, lipid peroxidation, and metallothionein-like proteins increased in exposed mussels. Clearance rate, respiration rate, and excretion rate decreased in a dose-dependent manner. Protein, carbohydrate, and lipid levels decreased with increasing exposure concentration (p < 0.001). Mitochondrial electron transport system activity increased, while cellular energy allocation (p < 0.001) and scope for growth decreased in a dose-dependent manner (p < 0.01). The significant increase in antioxidants suggests heightened oxidative stress in mussels under Cd exposure. The physiological activities of the mussels were severely affected, ultimately leading to a reduced scope for growth. The toxicological data generated in this study contribute to the development of seawater quality criteria for the metal Cd.

The physiological effects of acute and sub-lethal exposure to phenol on antioxidant enzyme activity in the freshwater sludge worm Tubifex tubifex

The current study investigates the severe effects of commonly employed chemicals, such as phenol, on the freshwater bottom-dwelling annelids of Tubifex tubifex. In an acute toxicity test, phenol's 96-hour LC50 value against Tubifex tubifex was identified to be 221.552 mg/L. Using the GUTS simulation, which places the GUTS-SD model on top of the GUTS-IT model, it was possible to confirm that the test organism would survive an acute exposure to phenol overall. After 14 days of treatment with 10 % and 20 % of the phenol's 96-hour LC50 values, long-term bioassays revealed changes in protein levels and in oxidative stress enzyme levels. Total protein concentration dropped during the bioassay, but levels of antioxidant enzymes (CAT, GST, SOD, and MDA) increased. The Pearson correlation matrix and the Integrated Biomarker Response (IBR) index were used for examining the relationship between biomarkers, toxicants, and phenol-induced stress. The results show that exposure to phenol is detrimental to the survival and general health of Tubifex tubifex.

Study on the Toxic Effects of Deltamethrin on Hematological Parameters of a Fresh Water Fish, Common Carp (Cyprinus carpio L.)

Fish health is adversely affected by pesticide contamination, which is a significant cause of pollution in freshwater ecosystems. One helpful technique for assessing the general health of different fish species is the analysis of blood parameters. Present study investigated the detrimental effects of deltamethrin on different hematological parameters of a fresh water fish, common carp (Cyprinus carpio). An experiment with a 28-day exposure to 1/20th and 1/10th of the 96-hour LC50 value (0.114µl/L) was conducted in order to investigate the effects of sub-lethal concentrations. On the 7th, 14th, 21st, and 28th day of exposure, several hematological parameters like Total Erythrocyte Count (TEC), Total Leukocyte Count (TLC), Hemoglobin (Hb), Hematocrit/Packed Cell Volume (Hct/PCV), Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC) were analyzed in comparison to control. After the exposure of different concentrations of deltamethrin significant decline (P*&lt;0.05 and P**&lt;0.01) in Hb, TEC, PCV and MCHC was noted as compared to control. On the contrary TLC, MCV and MCH showed increasing trend after the treatment of pesticide. This study showed that deltamethrin considerably altered the hematological markers of fish, even at sub-lethal concentrations.

Acute toxicity and sublethal effects of phenol on hematological parameters of channel catfish Ictalurus punctatus and pacu Piaractus mesopotamicus

Phenol is an aromatic chemical commonly found in domestic and industrial effluents that represents a worldwide concern in toxicology. When it reaches aquatic environments, significant damage in fishes is observed. The first aim of this study was to investigate the acute toxicity levels of phenol in Ictalurus punctatus and Piaractus mesopotamicus. The second objective was to evaluate the hematological parameters of I. punctatus and P. mesopotamicus after 96 hours exposure to sublethal concentration of phenol (10% of 96-hour LC50) and after post-exposure recovery period of 7 days. The main hypothesis of the study was that even sublethal phenol concentration could cause hematological alterations in fish. For 96-hour LC50 tests, both fish species were exposed to several phenol concentrations (in the range between 5 and 50 mg L-1) and the mortality were recorded after 24, 48, 72 and 96 hours. Phenol was notably more toxic to I. punctatus than P. mesopotamicus and the 96-hour LC50 values were 15.08 and 32.56 mg L-1, respectively. Sublethal exposure to phenol in P. mesopotamicus resulted in significant higher hematocrit level (Ht), hemoglobin content (Hb) and red blood cell count (RBC) in comparison with control group. In I. punctatus, Ht, Hb and RBC remained constant after 96-hour sublethal exposure. However, after the recovery period of 7 days a significant increase of RBC followed by reduction in mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were observed in I. punctatus. The sublethal responses to phenol revealed erythropoeisis in I. punctatus and respiratory distress in P. mesopotamicus. P. mesopotamicus presented excessive skin and gills mucus throughout the 96-hour LC50 tests. Acute toxicity tests and hematological responses after exposure to sublethal phenol concentration could be successfully used as a biomarker of stress in fish and may be applicable to investigate others toxic agents.

Indigo dyes: Toxicity, teratogenicity, and genotoxicity studies in zebrafish embryos

Wastewater released by textile dyeing industries is a major source of pollution. Untreated wastewater released from indigo dyeing operations affects aquatic ecosystems and threatens their biodiversity. We have assessed the toxicity of natural and synthetic indigo dye in zebrafish embryos, using the endpoints of teratogenicity, genotoxicity, and histopathology. The zebrafish embryo toxicity test (ZFET) was conducted, exposing embryos to ten concentrations of natural and synthetic indigo dyes; the 96-hour LC50 values were approximately 350 and 300 mg/L, respectively. Both dyes were teratogenic, causing egg coagulation, tail detachment, yolk sac edema, pericardial edema, and tail bend, with no significant difference in effects between the natural and synthetic dyes. Both dyes were genotoxic (using comet assay for DNA damage). Real-time RT-PCR studies showed upregulation of the DNA-repair genes FEN1 and ERCC1. Severe histological changes were seen in zebrafish larvae following exposure to the dyes. Our results show that indigo dyes may be teratogenic and genotoxic to aquatic organisms, underscoring the need for development of sustainable practices and policies for mitigating the environmental impacts of textile dyeing.

Investigating the impact of external application of formalin and potassium permanganate on hematological, immunological, and biochemical profiles in Labeo rohita fingerlings

The present study aimed to elucidate the suitability of formalin and KMnO4 as therapeutics for fish diseases in Indian major carp, Labeo rohita, while considering their impact on fish stress levels. Acute toxicity tests revealed that the 96-hour LC50 values for formalin and KMnO4 were 66.58 ppm and 2.89 ppm, respectively. Sub-lethal concentrations of formalin (6.65 ppm, 3.32 ppm, and 2.21 ppm) and KMnO4 (0.289 ppm, 0.145 ppm, and 0.096 ppm), along with control groups, were administered to the fish for different exposure periods (24, 48, 72, and 96 hours) and different hematological, biochemical, and immunological parameters were analyzed. The findings demonstrated that formalin exposure resulted in a significant decrease (p < 0.05) in hematological parameters, immunological parameters, and serum protein levels. Conversely, formalin exposure led to significant increases (p < 0.05) in serum glucose, SGOT, SGPT, and ALP levels. In contrast, KMnO4 exposure significantly decreased (p < 0.05) hematological parameters and serum protein levels, while significantly increasing (p < 0.05) immunological parameters. To evaluate curative efficacy, challenge studies were conducted using three sub-lethal concentrations of formalin and KMnO4 against Aeromonas hydrophila (ATCC 7966) infection. Based on the aforementioned results, the recommended doses of formalin and KMnO4 were found to be 6.65 ppm and 0.289 ppm, respectively.

Generation of oxidative stress in freshwater oligochaete Tubifex tubifex due to exposure to aniline: time and concentration dependent toxicity assessment

ABSTRACT Our current study examines the significant impact of aniline on the fish feed freshwater benthic annelid, Tubifex tubifex, including mortality, changes in total protein concentration and antioxidant enzyme activity (catalase, superoxide dismutase, glutathione-s transferase and glutathione peroxidase), as well as the generation of oxidative stress (by assessing malondialdehyde concentration). The 96-hour LC50 value of aniline is 276.940 mg/L. The General Unified Threshold Model of Survival (GUTS) was used to validate the survival rate pattern of the test organism in response to aniline at the acute level, with the GUTS-SD model better correctly predicting the expected course of population death. During long-term bioassay antioxidant enzymes activities (superoxide dismutase, glutathione-s transferase and glutathione peroxidase) and oxidative stress biomarkers concentration (malondialdehyde concentration) is substantially enhanced while protein concentration and Catalase activity are markedly reduced during the bioassay. The stress and detrimental effects of aniline on Tubifex tubifex were examined in the current study, taking into account all biomarkers, by utilising the Integrated Biomarker Response index. The results show that exposure to toxicants like aniline has a detrimental effect on Tubifex tubifex's survival rate and general health.

The Protective Role of Vitamin C on Heamatological (WBC and Hb) Alterations in Commom Carp During Chronic Toxicity of Lead Nitrate

This investigation intended to assess the outcome of haematological factors (WBCs and Hb) on common carp (Cyprinus carpio) of weight around (80 – 120 g) being exposed to various doses of lead nitrate and the protective role of Vitamin C in response to lead nitrate changes were studied. Chemicals (or elements) known as heavy metals are discharged into the surrounding environment as a consequence of commercial and industrial use as well as leaks from landfills. They are water-soluble but not biodegradable, and they are frequently firmly bound to proteins and polypeptides, even if previous research has issued warnings. The aquatic ecosystem is still impacted by several activities, changing the temperature and posing health risks to fish. The aquatic ecology becomes unbalanced as a result of heavy metals. Several lead nitrate concentrations were applied to the fish, and after 24, 48, 72, and 96 hours, (percentage)% mortality was recorded. Throughout the current experimental period, seven distinct concentrations of lead nitrate was used to determine the LC50 of the substance and evaluate its effect on common carp mortality. The lead nitrate concentrations ranged between 10 and 60 mg/l, and each concentration's death rate was determined. Lead nitrate was found to have an LC100 of 60 mg/l. Therefore, it was determined that the acute 96-hour LC50 value for the common carp, the fish used in this experiment, was 35 mg/l (ppm).

Haematological, biochemical, enzymological changes and mitochondrial dysfunction of liver in freshwater climbing perch Anabas testudineus during their acute and chronic exposure to sodium fluoride

Anthropogenic activities are increasing fluoride concentration in watercourses. The present study focuses on the sublethal toxicity of sodium fluoride during sub-chronic and chronic time periods in the freshwater fish Anabas testudineus. The 96-hour LC50 value for fluoride was found to be 616.50 mg/L. Excessive mucous production and hyper excitability, followed by loss of balance, were seen in fish under acute fluoride exposure. Significant reduction in yield and specific growth rate of fish were assessed at 15, 30 and 45-days exposure intervals. Different bio-indicators like Hepatosomatic-index, Gonadosomatic-index and fecundity were reduced significantly in fish exposed to 10% (61.6 mg/L) and 20% (123.2 mg/L) of 96 h of LC50 values of fluoride in comparison to control. Toxicant concentrations directly correlated with parameter lowering. Fluoride exposure increased plasma glucose, creatinine, AST, and ALT and reduced total RBC, haemoglobin content, Hct (%), plasma protein, and cholesterol. Moreover, fluoride exposure significantly reduces the mitochondrial membrane potential in liver. This may result in metabolic depression, haematological, biochemical, and enzymological stress. The in-silico structural analysis predicts that fluoride may impede cytochrome c oxidase of the electron transport system, hence inhibiting mitochondrial functionality. These findings collectively highlight the urgent need for stringent regulation and monitoring of fluoride levels in freshwater ecosystems, as the subchronic and chronic effects observed in A. testudineus may have broader implications for aquatic ecosystems.

Investigation of Acute Toxicity of Cyfluthrin on Zebrafish (Danio rerio)

Cyfluthrin is a synthetic pyrethroid that pollutes aquatic ecosystems and is also a potential toxic pollutant. Zebrafish (Danio rerio) were used in acute toxicity tests for bioassays. 96-hour LC50 values were determined for zebrafish. Experiments were performed in triplicate and the static test method of acute toxicity test was used. At the same time, behavioral changes were observed at each cyfluthrin concentration in fish. Data from cyfluthrin acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The 96-h LC50 value for zebrafish was calculated as 3.61 µg/L.

Developmental and neurobehavioral toxicity of 2,2′-methylenebis(6-tert-butyl-4-methylphenol) (antioxidant AO2246) during the early life stage of zebrafish

Background2,2′-Methylenebis (4-methyl-6-tert-butylphenol) (AO2246) is a synthetic phenolic antioxidant extensively used in food packaging bags and cosmetics. Recently, AO2246 was detected with unexpectedly high concentrations in plasma and breast milk samples from pregnant and lactating women. Hence, it is essential to conduct a thorough investigation to evaluate the detrimental effects of AO2246 on biota. ObjectiveTo investigate the developmental and behavioral toxicity of AO2246 in zebrafish, as well as the molecular mechanisms underlying these effects. MethodsZebrafish embryos were exposed to AO2246 at concentrations ranging from 0.05 to 10 μM for up to 6 days postfertilization (dpf). Hatching rate, survival rate, heart rate, and body length were measured. Locomotor behavioral and electrophysiologal analyses were performed. Two fluorescence-labeled transgenic zebrafish lines (endothelium-Tg and macrophage/microglia-Tg) were employed. RNA sequencing was carried out. ResultsAO2246 has a 96-hour LC50 value of 3 μM. The exposure of AO2246 resulted in a significant reduction in both hatching rate and heart rate. Analysis of locomotor behavior demonstrated that larvae exposed to AO2246 doses exceeding 2 μM exhibited a significant decrease in both total distance and mean velocity. Electrophysiological recordings demonstrated a noteworthy reduction in spike activity at a concentration of 3 μM, relative to control conditions. The administration of AO2246 at 3 μM elicited morphological reactivity and immune alteration of the midbrain microglia in the macrophage/microglia-transgenic zebrafish line, indicating a potential contribution of neurological disorders to behavioral defects. RNA sequencing analysis revealed altered gene expression profiles at high AO2246 concentrations, particularly the dysregulation of pathways associated with neuronal function. ConclusionsThe present study demonstrates that AO2246 exposure elicits developmental and neurobehavioral toxicity in zebrafish larvae. Specifically, exposure to AO2246 was found to cause disturbances in neuronal electrophysiological activity and neurological disorders, which ultimately led to the impairment of locomotor behavior in zebrafish larvae.

Variations in the Behaviour, Survival, Haematology, and Biochemistry of Ctenopharyngodon idella (Grass Carp) After Exposure to Commercial Grade Atrazine.

The current study assessed the harmful effects of Atrazine (ATZ) herbicide on haematology and biochemistry of the freshwater fish Ctenopharyngodon idella, a commercially significant fish in Pakistan. C. idella (13 ± 8.4cm; 132 ± 5.6g) was exposed to graded levels of ATZ, and its 96-hour LC50 value at 25°C was calculated to be 150.5µl/L. After exposure to ATZ, fish displayed rapid movements, a loss of balance in position and equilibrium, anxious swimming patterns, colour changes, and increased mucous production. The MCHC, MCH, RBCs, and Hb in C. idella decreased significantly (P < 0.05), whereas the MCV, Ht, and WBCs were significantly increased (P < 0.05). At different time intervals (24, 48, 72, and 96h) following ATZ administration (50, 100, 150, and 200µl/L), biochemical analysis significantly decreased (P < 0.05) triglyceride, total protein, cholesterol, and albumin levels, whereas glucose levels significantly increased (P < 0.05). We concluded that ATZ is toxic to C. idella, altering their haematology and blood biochemistry even after only a brief exposure.

Toxicity test of LC-50 (Lethal Concentration) surfactant LAS (Linear Alkylbenzene Sulfonate) against white snapper (Lates calcarifer) fingerlings on a laboratory scale

LAS (Linear Alkylbenzene Sulfonate) surfactants are the main cleaning agents from the anionic group found in detergents that are widely used in Indonesia. LAS decomposes in surface water for 1-2 days, in sediments it decomposes for 1-3 days, in marine and estuarine systems it decomposes for 5-10 days. LAS is generally degraded by as much as 90% within 3 months, with a time ranging from 5-30 days (World Health Organization, 1996). LAS surfactants can cause damage to the gill epithelium and blockage of branchiola channels in fish. This study aims to determine the toxic effect of LAS surfactant on the survival of white snapper (Lates calcarifer) fry and to determine the toxicity value of LC50 (Lethal Concentration) of LAS surfactant to white snapper (Lates calcarifer) fry on a laboratory scale. This research was carried out on September 21 – October 04, 2021 at the Marine Science Laboratory, Faculty of Agriculture, Malikussaleh University using laboratory experimental methods with 5 treatments, namely: control treatment A (0 ppm), B (0.83 ppm), C (1.58 ppm). ), D (2.16 ppm), and E (2.91 ppm). The results of this study cause barramundi to experience irregular movements, mouth opening and operculum tend to be fast and irregular, scales are pale and peeling, and cause death, LAS surfactants affect water quality such as pH and dissolved oxygen, but have no effect on salinity and temperature. The 24-hour LC50 value is 1.95 ppm, the 48-hour LC50 value is 1.86 ppm, the 72-hour LC50 value is 1.70 ppm, and the 96-hour LC50 value is 1.58 ppm.Key words : LAS surfactant; LC50; toxicity; white snapper

Toxicity test of LC-50 (Lethal Concentration) surfactant LAS (Linear Alkylbenzene Sulfonate) against white snapper (Lates calcarifer) fingerlings on a laboratory scale

LAS (Linear Alkylbenzene Sulfonate) surfactants are the main cleaning agents from the anionic group found in detergents that are widely used in Indonesia. LAS decomposes in surface water for 1-2 days, in sediments it decomposes for 1-3 days, in marine and estuarine systems it decomposes for 5-10 days. LAS is generally degraded by as much as 90% within 3 months, with a time ranging from 5-30 days (World Health Organization, 1996). LAS surfactants can cause damage to the gill epithelium and blockage of branchiola channels in fish. This study aims to determine the toxic effect of LAS surfactant on the survival of white snapper (Lates calcarifer) fry and to determine the toxicity value of LC50 (Lethal Concentration) of LAS surfactant to white snapper (Lates calcarifer) fry on a laboratory scale. This research was carried out on September 21 – October 04, 2021 at the Marine Science Laboratory, Faculty of Agriculture, Malikussaleh University using laboratory experimental methods with 5 treatments, namely: control treatment A (0 ppm), B (0.83 ppm), C (1.58 ppm). ), D (2.16 ppm), and E (2.91 ppm). The results of this study cause barramundi to experience irregular movements, mouth opening and operculum tend to be fast and irregular, scales are pale and peeling, and cause death, LAS surfactants affect water quality such as pH and dissolved oxygen, but have no effect on salinity and temperature. The 24-hour LC50 value is 1.95 ppm, the 48-hour LC50 value is 1.86 ppm, the 72-hour LC50 value is 1.70 ppm, and the 96-hour LC50 value is 1.58 ppm.Key words: LAS surfactant; LC50; toxicity; white snapper

Effects of Dimethoate Insecticide on Serum Biochemistry of African Catfish (Clarias gariepinus) Juveniles

The present study was designed to investigate acute toxicity of dimethoate on juvenile Clarias gariepinus. Catfish with mean weight and length of 24.01 ± 11.60 g and 13.98 ± 5.66 cm respectively were exposed to sub-lethal levels of dimethoate in static bioassay system for 28 days and mortality data was statistically evaluated using Finney’s Probit analysis. The 96-hour LC50 value for C. gariepinus was estimated as 29.05 mg/l. The value for the LC50 was used in deducing the sub-lethal concentrations (0.01, 0.15and 0.29 mg/l). Biochemical changes in the serum such as glycogen, total protein, cholesterol, urea and creatinine were analyzed after the exposure period (28 days). The glycogenlevel decreased in all sublethal exposures. An increase in cholesterol at lower exposure concentration, followed by slight increase in urea and creatinine among treated groups was recorded. Behavioural changes which includes changes in skin colour, jerking, restlessness, erratic swimming, among others were observed. Based on the result of this study, it was concluded that C. gariepinus juveniles are very sensitive to low concentration of dimethoate. Dimethoate is highly toxic to juvenile catfishes and as such measures must be taken to avoid its run-off into our aquatic environment thus jeopardizing the recruitment of juvenile catfishes into the fishery.

Acute Toxicity (LC50) Of Cyhalofop Butyl on Gambusia Holbrooki

Cyhalofob butyl is a synthetic herbist. This herbicide is a systemic herbicide and is used in weed control especially on celtic agriculture. In this study, the acute toxicity (LC50) of this herbist (Chillinger 200 EC 200, cyhalofob butyl) was investigated, which is currently used intensely in the fight against herbists in Thrace region, including Cyhalofob butyl. Acute toxicity (LC50 value) for this herbicide has been investigated in the common mosquito fish (Gambusia holbrooki) in Thrace Region. Lethal Dose 50 experiments were performed in 3 replicates in static test runs (water temperature 27.70 ±0.56 C, water pH 8.88± 0.37, and conductivity 718.25±21.113 µhos). The experiment results obtained for Chillinger 200 ec during the experiments were evaluated by Trimmed Spearman–Karber method. 96-hour LC50 value for the mosquito fish Gambusia holbrooki was calculated as 4.140 ppm.

Acute Toxicity of Copper and Zinc and their Lethal Concentration on Clarias Gariepinus (Cat Fish)

Due to uncontrolled discharge of industrial waste into water bodies leading to ecological risk from heavy metals, there have been increased mortality rate of aquatic lives, especially in the river-line areas of Nigeria. Most commonly identified metals were copper and zinc. As a result, this study investigated Acute toxicity of copper and zinc and their lethal concentration on Clarias gariepinus using the toxicity scale of 96hrLC50 values and the statistical Probit Analysis Method to determined their response to these metals. The Results showed that copper and zinc accumulation in the tissues of C. gariepinus and its mortality responses varied with concentration and period of exposure. copper (40, 60, 80 and100mg/l) and zinc (40, 60, 80 and100mg/l) exposed over 96-hour LC50 value for Clarias gariepinus was found to be 59.357mg/l for copper and 65.151mg/l for zinc respectively. Control mortality was however at 5%. At 95% lower and upper confidence limits for copper,the LC50 values were 44.394 and 67.848 mg/l , while zinc were 36.3 and 75.36 mg/l respectively. The result suggested that copper and zinc as common constituent in industrial wastes discharged into water bodies posses possible ecological risk to marine lives especially at high concentrations, therefore, it is important that the usage of these heavy metals are controlled.

Genotoxic, Histopathological and Oxidative Stress Responses in Catfish, Clarias gariepinus, Exposed to Two Antifouling Paints.

Background.Antifouling paints are enriched with biocides and employed in the maritime industry to protect moving and fixed surfaces from fouling activities of sea dwelling invertebrates. There is limited information on their effect on the non-target African catfish, Clarias gariepinus, a commonly consumed fish in Lagos.Objectives.This study investigated the effects of two commonly used antifouling paints (Berger TBT-free (A/F783 (H)), reddish brown color and Silka Marine lead based paint, pale orange color) on a non-target catfish species, Clarias gariepinus.Methods.The study involved an initial 96-hour acute toxicity assay followed by chronic toxicity evaluation (using 1/10th and 1/100th 96-hour median lethal concentration (LC50) values) for 28 days to determine the ability of the paints to induce micronucleus and red blood cell abnormalities, and histopathological as well as oxidative stress effects in the catfish.Examined anti-oxidative stress enzyme activities include superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and glutathione-s-transferase (GST).Results.Acute toxicity evaluation results indicated that the Berger paint was 16.1-times more toxic than Silka paint with 96-hour LC50 values of 0.71 mg/L and 11.49 mg/L, respectively. Results from the biochemical assay indicated significantly higher (P<0.05) levels of a lipid peroxidation product, malondialdehyde, in Silka-exposed catfish compared to the control. All enzymes showed significantly higher activities in Berger paint-exposed catfish compared to the control. There was evidence of micronucleated and binucleated cells in the red blood cells of fish exposed to both paints. Histopathological assessment indicated that the exposed fish gills showed evidence of abnormalities such as curved lamellae epithelial necrosis, epithelial lifting and hyperplasia. The liver samples of the catfish showed evidence of portal inflammation as well as mild to severe steatosis, while the gonads showed varying percentages of follicle degeneration.Conclusions.The present study combined an array of biomarkers to determine the negative health impacts of two commonly used antifouling paints on non-target catfish inhabiting Lagos Lagoon. Further in situ studies are recommended to determine the current status of the lagoon fish.Ethics Approval.Ethical approval was obtained from the Department of Zoology, University of Lagos, Post-Graduate Committee. Note that this work commenced before the establishment of the University of Lagos Ethical Committee for the use of animals and humans in scientific studies. The committee does not give retroactive approval but stands by existing approvals before its establishment. However, this study followed the World Medical Association principles on the treatment of animals used in research (https://www.wma.net/policies-post/wma-statement-on-animal-use-in-biomedical-research/), and also American Fisheries Society Guidelines for the Use of Fishes in Research (https://fisheries.org/policy-media/science-guidelines/guidelines-for-the-use-of-fishes-in-research/)

Dimethoate Induced Behavioural Changes in Juveniles of Cyprinus carpio var. communis under Temperate Conditions of Kashmir, India.

The present study was designed to investigate acute toxicity of dimethoate on juvenile Cyprinus carpio var. communis. Fishes weighing 10 ± 2 gms were selected and mortality data was statistically evaluated by Finney's Probit Method. The 96-hour LC50 value for Cyprinus carpio was found as 1.1 ppm in static bioassay system. Mean values of physicochemical parameters of aquarium waters determined during bioassay depicted slight variation indicating that the mortality in aquarium fishes occurred due to pesticide exposure and not suffocation. Lab. temperature ranged from 12 to 13°C; water temperature ranged from 11 to 12°C; dissolved oxygen ranged from 3.90 to 4.56 mg/L; pH ranged from 6.90 to 7.05; total dissolved solids ranged from 2.66 to 3.0 × 103 mg/L, while CO2 remained at a constant value of 2.0 mg/L. The fishes elicited various behavioural responses such as uncoordinated movements, convulsions, excessive mucus secretion, and imbalanced swimming which ended in a collapse to the bottom of the aquarium. Prior to death, the clinical signs like scale erosion, pale body colour, and hemorrhagic patches over the body were noticed which became more vivid up to the termination of experiments. Results of the study indicate potential toxicity of dimethoate in fingerlings of common carp for which the natural waterbodies must be continuously monitored to reduce its impact across food chains.