Department of Ecology, Faculty of Environmental Science and Natural Resource Management (MINA), Norwegian University of Life Sciences (NMBU), Ås, Norway.
Department of Environmental Science, Bangladesh University of Professional, Dhaka, Bangladesh.
Water Environ Res. 2024 Aug;96(8):e11097. doi: 10.1002/wer.11097.
Human welfare and biodiversity are at risk due to the deterioration of water and sediment quality. Particularly, in last few decades, global water and sediment quality degraded due to the rapid industrialization and urbanization. This study aimed to determine the concentration of nine heavy metals and metalloid (Pb, Cr, Cd, Hg, As, Mn, Ni, Cu, and Zn) and assess the ecological risks using different pollution indices (e.g., heavy metal pollution index [HPI], Nemerow pollution index [NI], geo-accumulation index [Igeo], contamination factor [CF], degree of contamination [CD] and pollution load index [PLI], ecological risk index [ERI]) in water and sediment of the Shitalakshya River, an industrially affected urban river of Bangladesh. For the first time, 20 water and sediment samples were collected across a wider geographical area of the Shitalakshya River during both monsoon and dry seasons and analyzed using the atomic absorption spectrometer. Average concentrations of heavy metals and metalloid in water were within the Bangladesh standard except for Cr (51.69 ppb) and Mn (228.20 ppb) during monsoon season, portraying potential ecological and human health risks. Besides, average concentration of Mn (549.75 and 370.93 ppb), Ni (549.75 and 370.93 ppb), and Cu (45.34 and 36.09 ppb) in sediment during both seasons were above international standard, implying risk to aquatic sediment biota. The average HPI values indicated moderate to high contamination, whereas the NI values implied polluted water in monsoon season with severe pollution in port area of the river. Similarly, Igeo, CF, CD, and PLI elucidated different levels of contamination in the sediment, particularly during dry season. The ERI values also referred moderate ecological risk in the sediment during dry season. Overall, our findings highlight the alarming level of heavy metal pollution in the Shitalakshya River, necessitating immediate action to protect the aquatic environment, sediment biota, and human health. PRACTITIONER POINTS: This study determined the concentration of heavy metals and metalloid in water and sediment of the Shitalakshya River, Bangladesh. The study revealed that the average concentration of Cr and Mn in water exceeded national standard, whereas Mn, Ni, and Cu in sediment exceeded international limit. Potential ecological risk of heavy metals was also assessed using different pollution indices. Calculated pollution indices indicated different degree of pollution, implying critical ecological condition due to heavy metal pollution in aquatic environment and sediment biota.
人类福利和生物多样性因水质和沉积物质量恶化而面临威胁。特别是在过去几十年中，由于工业化和城市化的迅速发展，全球水质和沉积物质量恶化。本研究旨在测定孟加拉国受工业影响的城市河流——希塔拉克夏河的水中和沉积物中 9 种重金属和类金属（Pb、Cr、Cd、Hg、As、Mn、Ni、Cu 和 Zn）的浓度，并使用不同的污染指数（例如，重金属污染指数[HPI]、内梅罗污染指数[NI]、地积累指数[Igeo]、污染系数[CF]、污染程度[CD]和污染负荷指数[PLI]、生态风险指数[ERI]）评估生态风险。首次在季风和旱季在希塔拉克夏河更广泛的地理区域采集了 20 个水和沉积物样本，并使用原子吸收光谱仪进行了分析。除了 Cr（51.69ppb）和 Mn（228.20ppb）在季风季节超过孟加拉国标准外，重金属和类金属在水中的平均浓度均在孟加拉国标准范围内，这表明存在潜在的生态和人类健康风险。此外，Mn（549.75 和 370.93ppb）、Ni（549.75 和 370.93ppb）和 Cu（45.34 和 36.09ppb）在两个季节的沉积物中的平均浓度均高于国际标准，这意味着对水生沉积物生物群有风险。平均 HPI 值表明存在中度至高度污染，而 NI 值表明季风季节的水受到污染，河流的港口地区污染严重。同样，Igeo、CF、CD 和 PLI 也说明了沉积物中不同程度的污染，特别是在旱季。ERI 值还表明旱季沉积物中存在中度生态风险。总的来说，我们的研究结果突显了希塔拉克夏河中重金属污染的严重程度，需要立即采取行动来保护水生态环境、沉积物生物群和人类健康。
