Spatial distribution and ecological risk of heavy metal in surface sediment of Old Brahmaputra River, Bangladesh

ABSTRACT

The study was conducted to investigate the concentrations, distributions, sources, and potential ecological risk of heavy metals in surface sediments from the Old Brahmaputra River. Sediment samples were collected from five sampling stations and analyzed with an inductively coupled plasma mass spectrometer (ICP-MS). The results showed that mean concentrations (mg/kg) of heavy metals were in order of Ni (58.82) > Cr (32.45) > Pb (21.04) > Cu (14.24) > Cd (3.81) > As (2.02). Element-specific environmental indices exposed that the ecological risks trailed in the same downward direction as Cd > Ni > Pb > As > Cu > Cr. The contamination factor (CF), enrichment factor (EF), and geo-accumulation index (Igeo) exposed all cases to a modest level of contamination except for Cd, which has a significant level of contamination. Only Ni and Cd were found to pose a high ecological risk for aquatic life based on the sediment quality guidelines. The prospective ecological risk factor and potential ecological risk both suggested low to moderate ecological risk. The river sediments were mostly uncontaminated or mildly contaminated, posing a minimal ecological risk. The study concluded that the Old Brahmaputra River is subjected to anthropogenic disturbances in its aquatic environment.

KEYWORDS:

• Elemental and spatial distribution
• Sediment quality guidelines (SQGs)
• Multivariate statistical analysis
• Ecological risk
• Old Brahmaputra River

Acknowledgements

Heartfelt thanks to Mr. Sajib Al Reza (Lecturer, Dept. of FTNS) and Md. Shakir Hossain (MS student, BAU) for their cooperation during the sample collection time, and Md. Mahfizur Rahman (Lab Attendant), Department of Environmental Science and Resource Management, Mawlana Bhashani Science and Technology University, Tangail-1902 for his help during the sample analysis period. Md. Sirajul Islam: Visualisation, Investigation, Supervision, Reviewing and Editing. Rifat Shahid Shammi: Conceptualisation, Methodology, Sample collection and processing, Laboratory analysis, Data curation, Data analyses, Writing- Original draft preparation. Rahiatul Jannat: Sample processing, Laboratory analysis, Data curation, Data analyses, Writing- Original draft preparation. Md. Humayun Kabir and Md. Saiful Islam: Conceptualisation, Methodology, Sample collection, Laboratory analysis, Data checking and validation, Visualisation, Writing- Reviewing and Editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Sincere appreciation to the University Grants Commission (UGC) of the People’s Republic of Bangladesh and the Research Cell of the Mawlana Bhashani Science and Technology University for the financial support (RC_FN_21/22-28) to carry out the research works efficiently and successfully.

Notes on contributors

Md. Sirajul Islam

Dr. Md. Sirajul Islam, a renowned Professor of Environmental Sciences. His research interests revolve around aquatic resource management including water pollution and remediation, wastewater treatment, environmental impact assessment, biodiversity conservation and climate change. He has developed an interest in multidisciplinary research on complex issues relating to toxic metals and its effects on the micro-environment. He has more than hundred publications in reputed journals in home and abroad, and presented many articles in national and international workshops, seminars and conferences.

Rifat Shahid Shammi

Rifat Shahid Shammi, MS student in the Department of Environmental Sciences and Resource Management (ESRM), MBSTU, Bangladesh. She obtained her B.Sc. (Hons.) in ESRM from the same institute. She is interested in the field of toxicology, pollution monitoring and remediation technologies of water and sediment.

Rahiatul Jannat

Rahiatul Jannat, obtained her undergraduate degree from the Department of Environmental Sciences and Resource Management (ESRM), MBSTU, Bangladesh. Currently, she is doing her MS in Environmental Science at the same department. She is interested in water quality, wastewater treatment and monitoring.

Md. Humayun Kabir

Md. Humayun Kabir, serving as an Assistant Professor at the Department of Environmental Sciences and Resource Management, MBSTU, Bangladesh. He is skilled in environmental monitoring and assessment with a special focus on pollution and ecological risk assessment. He also trying to explore biogeochemical processes and the fate and transport of emerging chemicals that impact human and environmental health.

Md. Saiful Islam

Dr. Md. Saiful Islam, a professor in the field of Soil Science. His research interests' natural resource management including water pollution and remediation, wastewater treatment, environmental impact assessment, biodiversity conservation and climate change.