Bioaccumulation of Heavy Metals in Different Tissues of Lates Calcarifer from Nizampatnam harbour and Kothapalem beach Areas, Andhra Pradesh

Abstract

This study aimed to assess the seasonal variation and bioaccumulation of heavy metals in different tissues of the marine fish Lates calcarifer, collected from two selected stations in the coastal region. The analysis was conducted during the pre-monsoon, monsoon, and post-monsoon seasons to evaluate the distribution of heavy metals in the gills, muscle, skin, and intestine tissues. The heavy metals analyzed included chromium (Cr), copper (Cu), manganese (Mn), lead (Pb), zinc (Zn), and cadmium (Cd), using standard analytical methods. The results indicated significant seasonal and tissue-specific variations in heavy metal concentrations. Among all the analyzed metals, chromium (Cr) consistently displayed the highest concentration across all tissues during the three seasons at both sampling stations. In the pre-monsoon season, the intestine showed the highest accumulation of chromium, with concentrations of 7.9μg/g at Station1 and 8.9μg/g at Station 2, followed by copper, manganese, and lead. During the monsoon season, the intestine again exhibited the highest metal accumulation, with chromium reaching 9.55μg/g, followed by copper at 9.0 μg/g and manganese at 6.5μg/g. Post-monsoon observations also indicated elevated chromium concentrations in the intestine, with values of 8.155μg/g at Station1 and 9.15μg/g at Station 2. Copper, lead, and manganese were recorded as the next predominant metals in all tissues. Among the examined tissues, the intestine demonstrated the highest bioaccumulation of heavy metals throughout the study period, highlighting its significant role in metal absorption and metabolism. The skin tissue consistently exhibited manganese as the third most accumulated metal during all seasons at both stations. In contrast, zinc (Zn) and cadmium (Cd) showed the lowest concentrations across all analyzed tissues. This study underscores the influence of seasonal variations on heavy metal accumulation in fish tissues and emphasizes the importance of continuous monitoring of coastal aquatic ecosystems to assess environmental pollution and potential risks to human health.