Potential pollution sources of heavy metals and nutrient variability in water of Sandwip Island, Patenga Coast, and Karnaphuli River

This study aims to assess the spatial variations in heavy metal contamination and nutrient levels in the water bodies of the Lower Meghna Estuary (Sandwip), Patenga Coast, and the Karnaphuli River. The major pollution sources, including industrial effluents, urban runoff, and sedimentation have also been identified. The results highlight the ecological risks posed by heavy metals, providing critical data for informing environmental management strategies in these coastal ecosystems. A comprehensive analysis of 24 elements, including heavy metals and other trace elements, (Sb, Ba, Se, Sn, As, Cr, Cd, Cu, Pb, Ni, Ag, Zn, Mn, B, Fe, Al, Ca, Mg, K, Sr, P, Li, Mo, Ti) and selected nutrient ions (F - , Cl - , NO 2 - , Br-, NO 3 - , SO 4 2- ) was conducted across multiple sampling points. The results revealed noteworthy spatial and temporal trends in heavy metal concentrations. For instance, Sb, Ba, and Se exhibited varying levels across different sites, while the presence of Cd, Cu, and Zn indicated potential anthropogenic influences. Patenga has significantly elevated levels of several elements, including Ca (111.76 mg/L), K (270.65 mg/L), B (1.423 mg/L), and Ni (0.11 mg/L) compared to both Karnaphuli and Sandwip. Cu was found at very low concentrations (<0.01 mg/L in Karnaphuli, 0.064 mg/L in Patenga), and Pb remained near the guideline threshold (0.012–0.013 mg/L). Nutrient analysis unveiled diverse ion concentrations, suggesting dynamic ecological processes. These findings are crucial for understanding the environmental health of these water bodies. The data can guide policymakers and environmental scientists in developing strategies for mitigating contamination and preserving the ecological balance of these vital ecosystems. Further research is recommended to monitor long-term trends and assess the potential impacts on aquatic life and human health.