Heavy metal contamination level in selected fishes of the Balu river in Bangladesh: Health risk assessments

Abstract

Metal contamination in water bodies poses serious environmental and health risks due to bioaccumulation in aquatic organisms, particularly fish. This study aimed to assess heavy metal contamination in three fish species-Systomus sarana (SS), Pethia ticto (PT), and Mastacembelus armatus (MA)-from Fakirkhali Bazar, Beraid Bridge, and Isapur Bazar in the Balu River, a site influenced by industrial, agricultural, and residential activities. Muscle samples were analyzed for Pb, Cd, Cr, Cu, As, and Ni concentrations using atomic absorption spectrophotometry (AAS). Principal component analysis (PCA) and cluster analysis were employed to identify pollution sources. Human health risks were evaluated using estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TR). Concentrations of Pb, Cd, Cr, and As in fish muscles (Pb: 3.28±0.08–6.26±1.98 mg/kg; Cd: 2.98±0.07–5.86±1.21 mg/kg; Cr: 1.99±0.07–5.64±1.74 mg/kg; As: 0.29±0.003–0.49±0.023 mg/kg) exceeded FAO/WHO and MOFL guideline values (Pb: 0.30, Cd: 0.05, Cr: 1.00, As: 1.00 mg/kg). PCA and cluster analyses indicated that heavy metal pollution primarily originated from anthropogenic sources, including industrial effluents, agricultural runoff, and residential wastewater. Health risk assessments suggested that long-term exposure to elevated Pb, Cr, and As could pose non-carcinogenic risks, while Cd, Cr, As, and Ni may increase cancer risk for local populations consuming contaminated fish. The findings emphasize the need for regular monitoring and coordinated efforts to reduce heavy metal pollution, protect public health, and preserve the Balu River ecosystem.

Bangladesh J. Sci. Ind. Res. 61(1), 31-54, 2026