Acute and chronic toxic effect of lead (Pb) and zinc (Zn) on biomarker response in post larvae of Penaeus monodon (Fabricus, 1798)

Abstract

Metal pollution produces damage to marine organisms at the cellular level possibly leading to ecological imbalance. The present investigation focused on the acute and chronic toxicity of lead (Pb) and zinc (Zn) by examining the effects of biomarker enzymes in post-larvae of Penaeus monodon (Tiger prawn). Antioxidant biomarker responses such as lipid peroxidation (LPO) and catalase (CAT) activity for Pb and Zn were determined following chronic exposure. Acute Lethal Concentration ₅₀ (LC₅₀) values observed in the study at 96 h for Pb and Zn at 5.77 ± 0.32 mg L⁻¹ and 3.02 ± 0.82 mg L⁻¹, respectively. The estimated No Observed Effect Concentration and Lowest Observed Effect Concentration values for Pb were 0.014 and 0.029 mg L⁻¹ and that recorded for Zn was 0.011 and 0.022 mg L⁻¹, respectively. Among the two metals studied, toxicity of Zn was found to be greater to P. monodon than Pb. The activities of antioxidant defense enzymes and total protein content differed significantly from control following exposure to both metals. Overall, the biomarker studies demonstrated that alterations in antioxidant enzymes and induction of LPO reflect the consequences of heavy metal exposure in P. monodon.

Keywords:

• bioaccumulation
• catalase
• lipid peroxidation
• lead
• Penaeus monodon
• toxicity
• zinc

Acknowledgments

The authors express their gratitude to Ministry of Earth Science, Government of India, New Delhi (Project Grant No. OES/ICMAM-PD/11thPlan/ME/IOM/56/2007) for their gratitude funds to conduct this study.