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Abstract Submission No. | ABS-2022-09-0427 |
Title of Abstract | Toxicity effects of cadmium (Cd) on the fish Etroplus suratensis (Bloch, 1790), Cochin Estuarine System, Southwest Coast, India |
Authors | K V Neethu *, P. Hari Praved, N. G. Athul Krishna, B. P. Aneesh, S. Bijoy Nandan |
Organisation | Cochin University of Science and Technology |
Address | Dept. of Marine Biology, Microbiology and Biochemistry, CUSAT ERNAKULAM, COCHIN, India Pincode: 682016 Mobile: 9544189134 E-mail: neethukv457@gmail.com |
Country | India |
Presentation | Poster |
Abstract | Cadmium is a highly toxic heavy metal with no physiological benefits. Increased Cd concentrations are a pressing issue in the Cochin estuarine system (CES). Dissolved Cd recorded an average of 0.88 ± 0.45 μg L-1 during premonsoon, 1.64 ± 0.79 μg L-1 during monsoon and 1.02± 0.49 μg L-1 during postmonsoon. Sediment bound Cd recorded an average of 6.81 ± 5.28 μg g-1 during premonsoon, 2.198 ± 0.686 μg g-1 during monsoon and 9.23 ± 11.01 μg g-1 during post monsoon period. Geoaccumulation index and contamination factor shows CES is highly polluted with Cd. However, research on the effects of Cd exposure on native organisms in the estuary is hard to extract. Hence, the present study evaluated the toxicity effects of Cd on the fish, Etroplus suratensis, native to Cochin estuary. The 96 h. effective median lethal concentration (LC50) for Cd was 1.21 mg L-1. The NOEC (No Observed Effect Concentration) and LOEC (lowest Observed Effect Concentration) were 0.21 mg L-1 and 0.12 mg L-1 respectively. The chronic toxicity value for Cd was 0.16 mg L-1. Behavioral, neurotoxic and oxidative stress biomarkers were assessed in E. suratensis after chronic toxicity test. The AChE activity decreased with increasing exposure concentration. Highest activity was found in unexposed group (13.6 U/g) and lowest (7.65 U/g) was in fishes exposed to 0.68 mg L-1. Behavioral changes such as rubbing, nudging, surfacing, partial jerking and burst swimming were observed in Cd exposed groups. Control fishes showed normal behavior throughout the observation period. The antioxidant enzymes, super oxide dismutase (SOD), malate dehydrogenase (MDH) and esterase (EST) showed variations from control groups. The SOD showed highest activity in control and lowest activity was at LOEC. Catalase showed decreased activity with increase in cadmium concentration. Highest MDH activity was observed at NOEC and lowest activity was observed at highest exposure concentration. Key words: Etroplus suratensis, Cadmium, Neurotoxicity, Behavior, Oxidative stress |