Sayed Tariq Uzzaman¹, Shamshad B. Quaraishi², Salma Begum^1,

Heavy metals are raising worldwide concerns owing to their potential effects on the environment. The present research analyzed heavy metals in the estuarine fish (Johnius dussumieri) sampled from the downstream Pasur estuarine Kokilmoni area of the Sundarbans, Bangladesh, during summer (March) and winter (November), 2022. Lead (Pb), Chromium (Cr) and Cadmium (Cd) were measured following a validated and accredited test method using graphite furnace atomic absorption spectrometry (GFAAS; Varian AA Duo 240 FS and Varian 280Z). Mercury (Hg) and Arsenic (As) in fish extracts were determined by cold vapor and hydride generation atomic absorption spectrometry (CVAAS) respectively. Mean concentrations (mg/kg) of Pb, Cd, As, Hg and Cr, were 2.93 ± 0.91, 0.057 ± 0.020, 0.144±0.054, 0.164±0.150 and 1.633± 1.450. ANOVA show that mean concentrations of Pb was significantly (p< 0.001) higher than the FAO and WHO recommended value whereas Cd, As and Hg were significantly (p< 0.001) lower. The Levene’s test show winter fish population has significantly higher Pb and Cr concentrations than summer populations (p< 0.05). Pearson Correlation analysis (p<0.05) quantified that Cr is strongly correlated with Pb (r=0.974) and Cd (r=0.612) at the 0.01 level (two tailed), Cd is strongly correlated with Pb (r=0.666). Principal component analysis was executed for the five heavy metals and revealed that two principal components covering 71.86% of the cumulative variance. The PC1 variable loading appeared to strongly be influenced by Pb, Cr, and Cd (0.970, 0.951, and 0.797 respectively). The variables loading on PC2 has influenced by As and Hg. Cumulative variance of component 1 accounts 51.423%, the component 2 accounts 20.445%. Therefore it can be concluded that Pb is supposed to be higher due to anthropogenic influences such as lead–acid battery industries, agricultural pesticides, industrial and different domestic uses of metals in the upstream Pasur. Heavy metals need to be monitored regularly for the sustainable management of the pristine Sundarbans ecosystem. Further time and space bound data is needed to understand the detailed metal trajectory in the coastal fishes of the Sundarbans.

heavy metal, Johnius dussumieri, assessment, the Sundarbans, Bangladesh