MONITORING OF TOXICOLOGICAL IMPACTS OF LAMBDA CYHALOTHRIN ON FISH USING MULTI-BIOMARKER APPROACH

Abstract

Agricultural runoff and industrial effluents are directly contributing to the surface water contamination. Pesticides coming from these sources are highly toxic contaminants and their indiscriminate usage is a serious environmental threat especially for aquatic life. These chemical represent a substantial damage to living organisms as damage to reproductive, immune, endocrine and nervous systems. Toxicity of pesticides fluctuates with variation in temperature, as temperature increases it may increase or decrease. The aim of this study was to perform acute and sub-acute toxicity test to determine LD-50 (Lethal dose 50) of Lambda cyhalothrin (a synthetic pyrethroid insecticide) and to evaluate its toxic impacts on grass carp (Ctenopharyngodon idella). LD-50 was initially measured for two temperatures because it is regulated by temperature as concentrations of toxic chemicals which are not active at low and moderate temperatures proved fatal with increase in water temperature The results indicated that the LD50 at 27 and 13ºC was 1.17 and 1.5 μg/L respectively. Blood glucose and protein levels increased initially with dose and time from 24 to 72 hours and decreased at 96 hours. In the observed values of experimental and control group there was significant difference (P<0.05). Triglycerides also have presented some fluctuating trends with increase dose concentration and exposure time while increased ALT level was observed at the end of experiment due to abnormal hepatic functions. Values observed in exposed group were significantly different (P< 0.05) from the control group. Oxidative stress due to increased ROS was significantly higher (P< 0.05) in brain and gills of experimental group as compared with control group. Respiratory burst activity also shown increasing trend with increased dose and prolonged exposure in the exposed fish as resulted values were significantly higher (P< 0.05) than control. Genotoxicity assessment revealed that there was significant (P< 0.05) increase in DNA% damage, tail length and olive tail moment in experimental group as compared to control group. Bioaccumulation was also observed in the muscle tissues after exposure to the Lambda cyhalothrin Morphological and histological alterations observed in fish liver and gills tissues showed different abnormalities in microscopic visualization. Abnormal behavioral patterns including more mucus on gills, surfacing and loss of balance were observed in the exposed fish. Keywords: LD-50, Oxidative stress, temperature, comet assay, cytotoxicity, Lambda cyhalothrin, genotoxicity, histopathology.