Physical and Chemical Characteristics of Water in Sangu-Matamuhuri Rivers along the South-Eastern part of Bangladesh and Heavy Metal Contamination with Associated Health Risk

Abstract

The study was conducted to determine the physical and chemical characteristics and heavy metal contamination in water along with associated health risks in Sangu and Matamuhuri rivers, located in the hilly watershed of south-eastern part in Bangladesh. Water samples were collected from five selected locations of both rivers during October, 2022 - September, 2023 and analyzed for pre-monsoon (February – May, 2023), monsoon (June – September, 2023) and post-monsoon (October, 2022 – January, 2023) seasons considering physical parameters including temperature, electrical conductivity (EC), turbidity, total dissolved solid (TDS), total suspended solid (TSS), and chemical parameters including pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD) and chloride. For assessing health risk, the contamination factor (CF), pollution load index (PLI), hazard quotient (HQ), and hazard index (HI) were evaluated. Water quality index was higher than 100, indicates the water was unsuitable for drinking. The mean concentration of heavy metals in water of Sangu river showed the pattern as Fe > Mn > Zn > Pb > Cr > Ni > Cu > Hg > Co > Se > Cd > Be, whereas for the Matamuhuri river as Fe > Mn > Pb > Zn > Cr > Ni > Cu > Hg > Co > Se > Cd > Be during September, 2023. Fe and Pb concentrations were found higher than the standard limit of inland surface water, suggested by Department of Environment (DoE), Bangladesh. The CF values for Sangu river ranged from 0.001 to 1.6 and for Matamuhuri river ranged from 0.003 to 3.9, suggest low contamination. The PLI values (Sangu = 0.055, Matamuhuri = 0.084) showed the pollution level not influenced by presence of less amount of heavy metals. Cancer risk for adults in surface water showed low cancer risk (CR < 10-6) for Cd, Cr, and Pb. The implications of these findings may help to raise awareness among the river water users for keeping water in good condition and thereby getting more ecosystem services.