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Walton RE, Moorhouse HL, Roberts LR, Salgado J, Ladd CJT, Do NT, Panizzo VN, Van PDT, Downes NK, Trinh DA, McGowan S, Taylor S, Henderson ACG. Using lake sediments to assess the long-term impacts of anthropogenic activity in tropical river deltas. THE ANTHROPOCENE REVIEW 2024; 11:442-462. [PMID: 39156121 PMCID: PMC11324390 DOI: 10.1177/20530196231204334] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/20/2024]
Abstract
Tropical river deltas, and the social-ecological systems they sustain, are changing rapidly due to anthropogenic activity and climatic change. Baseline data to inform sustainable management options for resilient deltas is urgently needed and palaeolimnology (reconstructing past conditions from lake or wetland deposits) can provide crucial long-term perspectives needed to identify drivers and rates of change. We review how palaeolimnology can be a valuable tool for resource managers using three current issues facing tropical delta regions: hydrology and sediment supply, salinisation and nutrient pollution. The unique ability of palaeolimnological methods to untangle multiple stressors is also discussed. We demonstrate how palaeolimnology has been used to understand each of these issues, in other aquatic environments, to be incorporated into policy. Palaeolimnology is a key tool to understanding how anthropogenic influences interact with other environmental stressors, providing policymakers and resource managers with a 'big picture' view and possible holistic solutions that can be implemented.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Suzanne McGowan
- University of Nottingham, UK
- Netherlands Institute of Ecology The Netherlands
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2
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Rizzello S, Scaraggi M, Nelson AD, Primavera L, Napoli G, Stecca G, Vitolo R, De Bartolo S. Multiscaling behavior of braided channel networks: An alternative formulation of Taylor's law variate transformations. Phys Rev E 2024; 109:034306. [PMID: 38632724 DOI: 10.1103/physreve.109.034306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 02/14/2024] [Indexed: 04/19/2024]
Abstract
Braided channel networks exhibit a complex interplay between spatial and temporal dynamics. Their behavior is characterized by both simple and multiscaling patterns, and the mechanisms underlying the stochastic processes associated with this dynamics remain incompletely understood. Leveraging Taylor's pioneering work [Nature (London) 189, 732 (1961)NATUAS0028-083610.1038/189732a0], which unveiled scaling relations in a plethora of natural phenomena through what is now known as the Taylor power law (TPL), we propose a physical interpretation of braided channel systems. This interpretation utilizes a specific class of transformation functions applied to the mean of fluvial geomorphic variables measured along cross sections, namely, the number of wet channels, the average width of wet channels, and the entropic braiding index. By analyzing remotely sensed data of the Brahmaputra-Jamuna River in Bangladesh we obtain valuable insight into the spatiotemporal scaling of these geomorphological variables and gather a deeper understanding of the complexity of braided channel systems. Finally, through a direct analysis employing the TPL in conjunction with a fixed-mass multifractal algorithm, we prove that braided channel networks exhibit a multiscaling behavior.
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Affiliation(s)
- Stefano Rizzello
- European Maritime Environmental Research (EUMER), University of Salento, Lecce 73100, Italy
- Department of Engineering for Innovation, University of Salento, Lecce 73100, Italy
| | - Michele Scaraggi
- Department of Engineering for Innovation, University of Salento, Lecce 73100, Italy
- Center for Biomolecular Nanotechnologies, Italian Institute of Technology, Arnesano 73010, Italy
| | - Andrew D Nelson
- Northwest Hydraulic Consultants, Bellingham, Washington 98225, USA
| | | | - Gaetano Napoli
- Department of Mathematics and Applications "R. Caccioppoli", University of Naples "Federico II", Naples 80126, Italy
| | - Guglielmo Stecca
- National Institute of Water and Atmospheric Research, Christchurch 8011, New Zealand
| | - Raffaele Vitolo
- Department of Mathematics and Physics "E. De Giorgi", University of Salento, Lecce, Italy and INFN, Section of Lecce 73100, Italy
- Istituto Nazionale di Fisica Nucleare, Section of Lecce, Via per Monteroni, Lecce 73100, Italy
| | - Samuele De Bartolo
- European Maritime Environmental Research (EUMER), University of Salento, Lecce 73100, Italy
- Department of Engineering for Innovation, University of Salento, Lecce 73100, Italy
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3
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Chowdhury A, Naz A, Maiti SK. Distribution, speciation, and bioaccumulation of potentially toxic elements in the grey mangroves at Indian Sundarbans, in relation to vessel movements. MARINE ENVIRONMENTAL RESEARCH 2023; 189:106042. [PMID: 37329607 DOI: 10.1016/j.marenvres.2023.106042] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/19/2023]
Abstract
Sundarban is the world's largest mangrove wetland and home of 4.6 million people (Indian part), whose principal mode of communication is motorized boats (ferries). This study shed light on the role played by ferry movement in the speciation (following the BCR three-step sequential extraction method), ecological impact and bioaccumulation of potentially toxic elements (PTEs) in plant tissues (root and lamina) of grey mangrove (Avicennia marina) found near the five ferry ghats (ports). One-way ANOVA showed variation in major soil parameters (silt, clay, organic carbon, pH, Electrical conductivity) and PTEs (As, Cd, Cr, Cu, Hg, and Pb) between sites. Sequential extraction revealed that Cd was present in the 'exchangeable' form across the sites, Pb was in the 'reducible' form, and the rest of the PTEs were majorly found in 'residual' phase. Pollution indices revealed moderate to heavy contamination and considerable potential ecological risk due to Cd. Pearson correlation statistics and concentration variations indicate a relation between Pb and ferry movement frequency in the sites. Higher bioconcentration of Pb in the roots of A. marina, indicates phytostabilization action. Translocation factor for Cd in the leaves, indicates phytoextraction by A. marina. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed a close association between vehicle movement and Hg, Pb, Silt fraction, electrical conductivity, Cr, and As. This study recommends regular pollution monitoring across Sundarbans, as the PTEs in sediment-plant matrix can impact the higher trophic levels, human health through possible biomagnification in the detritus food chain, and can adversely impact the existing conservation initiatives.
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Affiliation(s)
- Abhiroop Chowdhury
- Jindal School of Environment and Sustainability, O.P. Jindal Global University, Sonipat, Haryana 131001, India; Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, Jharkhand, India.
| | - Aliya Naz
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, Jharkhand, India; Jindal School of Liberal Arts and Humanities, O.P. Jindal Global University, Sonipat, Haryana, 131001, India
| | - Subodh Kumar Maiti
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, Jharkhand, India
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Rashid MB. Monitoring of drainage system and waterlogging area in the human-induced Ganges-Brahmaputra tidal delta plain of Bangladesh using MNDWI index. Heliyon 2023; 9:e17412. [PMID: 37416649 PMCID: PMC10320178 DOI: 10.1016/j.heliyon.2023.e17412] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 07/08/2023] Open
Abstract
Waterlogging is one of the major global problems which affects agro-economic activities around the world. In the coastal areas of Bangladesh, especially the southwestern coast, drainage congestion and waterlogging are very common which makes the area uninhabitable. Therefore, timely checking of drainage systems and surface water, and conveying data on the dynamics of drainages and surface water are important for plan and supervisory processes. The present study took an effort to illustrate the waterlogging and morphological change of the rivers in the southwestern coast of Bangladesh through the Modification Normalized Difference Water Index (MNDWI) values which are valuable indicators for monitoring the water area and land use pattern change. Landsat images (Landsat L8 Oli TIRS, Landsat ETM+, Landsat TM) were used in the research. The study reveals that from 1989 to 2020, the shallow water area (mostly covered with rivers) decreased by ∼14.30 km2 yr-1, whereas the wet-land area (mostly covered with beels and water logging areas) increased by ∼ 67.12 km2 yr-1. The bare land area also increased at a rate of ∼ 36.90 km2 yr-1. On the other hand, the green vegetation decreased at a rate of ∼166.1 km2 yr-1, whereas the moderate green vegetation area increased by ∼ 69.77 km2 yr-1 for the same period. In the coastal zones of Bangladesh, the polders, embankments, upstream dams, etc., enhance more sedimentation within the channels rather than in the nearby tidal plains. As a result, the shallow water area which is mostly covered by rivers is gradually decreasing. Moreover, due to increase in wet-land areas with salinity intrusions which affect the vegetation. Therefore, the green vegetation area is regularly declining due to demolition or conversion to moderate green vegetation. The findings of the research will be supportive for coastal scientists worldwide, policy makers & planners, and finally supportive for sustainable management of the coastal areas including Bangladesh.
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Raff JL, Goodbred SL, Pickering JL, Sincavage RS, Ayers JC, Hossain MS, Wilson CA, Paola C, Steckler MS, Mondal DR, Grimaud JL, Grall CJ, Rogers KG, Ahmed KM, Akhter SH, Carlson BN, Chamberlain EL, Dejter M, Gilligan JM, Hale RP, Khan MR, Muktadir MG, Rahman MM, Williams LA. Sediment delivery to sustain the Ganges-Brahmaputra delta under climate change and anthropogenic impacts. Nat Commun 2023; 14:2429. [PMID: 37105978 PMCID: PMC10140268 DOI: 10.1038/s41467-023-38057-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
The principal nature-based solution for offsetting relative sea-level rise in the Ganges-Brahmaputra delta is the unabated delivery, dispersal, and deposition of the rivers' ~1 billion-tonne annual sediment load. Recent hydrological transport modeling suggests that strengthening monsoon precipitation in the 21st century could increase this sediment delivery 34-60%; yet other studies demonstrate that sediment could decline 15-80% if planned dams and river diversions are fully implemented. We validate these modeled ranges by developing a comprehensive field-based sediment budget that quantifies the supply of Ganges-Brahmaputra river sediment under varying Holocene climate conditions. Our data reveal natural responses in sediment supply comparable to previously modeled results and suggest that increased sediment delivery may be capable of offsetting accelerated sea-level rise. This prospect for a naturally sustained Ganges-Brahmaputra delta presents possibilities beyond the dystopian future often posed for this system, but the implementation of currently proposed dams and diversions would preclude such opportunities.
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Affiliation(s)
- Jessica L Raff
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA.
| | - Steven L Goodbred
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA.
| | - Jennifer L Pickering
- Center for Applied Earth Science and Engineering Research, The University of Memphis, Memphis, TN, USA
| | | | - John C Ayers
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA
| | - Md Saddam Hossain
- Center for Applied Earth Science and Engineering Research, The University of Memphis, Memphis, TN, USA
| | - Carol A Wilson
- Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA, USA
| | - Chris Paola
- Department of Earth and Environmental Sciences, St Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, USA
| | - Michael S Steckler
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Dhiman R Mondal
- Haystack Observatory, Massachusetts Institute of Technology, Westford, MA, USA
| | - Jean-Louis Grimaud
- Centre de Géosciences, PSL University/ MINES Paris, Fontainebleau, France
| | - Celine Jo Grall
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
- CNRS - Littoral Environnement et Sociétés, La Rochelle University, La Rochelle, France
| | - Kimberly G Rogers
- Institute for Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
| | | | | | - Brandee N Carlson
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA
| | | | - Meagan Dejter
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA
| | - Jonathan M Gilligan
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA
| | - Richard P Hale
- Department of Ocean & Earth Sciences, Old Dominion University, Norfolk, VA, USA
| | - Mahfuzur R Khan
- Department of Geology, University of Dhaka, Dhaka, Bangladesh
| | - Md Golam Muktadir
- Department of Environmental Science, Bangladesh University of Professionals, Dhaka, Bangladesh
| | - Md Munsur Rahman
- Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh
| | - Lauren A Williams
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA
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Huang Y, Knappett PSK, Berube M, Datta S, Cardenas MB, Rhodes KA, Dimova NT, Choudhury I, Ahmed KM, van Geen A. Mass fluxes of dissolved arsenic discharging to the Meghna River are sufficient to account for the mass of arsenic in riverbank sediments. JOURNAL OF CONTAMINANT HYDROLOGY 2022; 251:104068. [PMID: 36108569 DOI: 10.1016/j.jconhyd.2022.104068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 08/15/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Shallow (<30 m) reducing groundwater commonly contains abundant dissolved arsenic (As) in Bangladesh. We hypothesize that dissolved As in iron (Fe)-rich groundwater discharging to rivers is trapped onto Fe(III)-oxyhydroxides which precipitate in shallow riverbank sediments under the influence of tidal fluctuations. Therefore, the goal of this study is to compare the calculated mass of sediment-bound As that would be sequestered from dissolved groundwater As that discharges through riverbanks of the Meghna River to the observed mass of As trapped within riverbank sediments. To calculate groundwater discharge, a Boussinesq aquifer analytical groundwater flow model was developed and constrained by cyclical seasonal fluctuations in hydraulic heads and river stages observed at three sites along a 13 km reach in central Bangladesh. At all sites, groundwater discharges to the river year-round but most of it passes through an intertidal zone created by ocean tides propagating upstream from the Bay of Bengal in the dry season. The annualized groundwater discharge per unit width at the three sites ranges from 173 to 891 m2/yr (average 540 m2/yr). Assuming that riverbanks have been stable since the Brahmaputra River avulsed far away from this area 200 years ago and dissolved As is completely trapped within riverbank sediments, the mass of accumulated sediment As can be calculated by multiplying groundwater discharge by ambient aquifer As concentrations measured in 1969 wells. Across all sites, the range of calculated sediment As concentrations in the riverbank is 78-849 mg/kg, which is higher than the observed concentrations (17-599 mg/kg). This discovery supports the hypothesis that the dissolved As in groundwater discharge to the river is sufficient to account for the observed buried deposits of As along riverbanks.
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Affiliation(s)
- Yibin Huang
- Dept. Geology & Geophysics, Texas A&M University, College Station, TX 77843, USA.
| | - Peter S K Knappett
- Dept. Geology & Geophysics, Texas A&M University, College Station, TX 77843, USA
| | - Michelle Berube
- Dept. Geological Sciences, Kansa State University, Manhattan, KS 66506, USA.
| | - Saugata Datta
- Dept. Geological Sciences, The University of Texas, San Antonio, TX 78249, USA.
| | - M Bayani Cardenas
- Dept. Geological Sciences, The University of Texas, Austin, TX 78712, USA.
| | - Kimberly A Rhodes
- Water Management and Hydrological Sciences Program, Texas A&M University, College Station, TX 77843, USA
| | - Natasha T Dimova
- Dept. Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA.
| | | | - Kazi M Ahmed
- Dept. Geology, University of Dhaka, Dhaka 1000, Bangladesh
| | - Alexander van Geen
- Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
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7
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Rahman MM, Haque A, Nicholls RJ, Darby SE, Urmi MT, Dustegir MM, Dunn FE, Tahsin A, Razzaque S, Horsburgh K, Haque MA. Sustainability of the coastal zone of the Ganges-Brahmaputra-Meghna delta under climatic and anthropogenic stresses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 829:154547. [PMID: 35302026 DOI: 10.1016/j.scitotenv.2022.154547] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 05/13/2023]
Abstract
The Ganges-Brahmaputra-Meghna (GBM) delta is one of the world's largest deltas. It is currently experiencing high rates of relative sea-level rise of about 5 mm/year, reflecting anthropogenic climate change and land subsidence. This is expected to accelerate further through the 21st Century, so there are concerns that the GBM delta will be progressively submerged. In this context, a core question is: can sedimentation on the delta surface maintain its elevation relative to sea level? This research seeks to answer this question by applying a two-dimensional flow and morphological model which is capable of handling dynamic interactions between the river and floodplain systems and simulating floodplain sedimentation under different flow-sediment regimes and anthropogenic interventions. We find that across a range of flood frequencies and adaptation scenarios (including the natural polder-free state), the retained volume of sediment varies between 22% and 50% of the corresponding sediment input. This translates to average rates of sedimentation on the delta surface of 5.5 mm/yr to 7.5 mm/yr. Hence, under present conditions, sedimentation associated with quasi-natural conditions can exceed current rates of relative sea-level rise and potentially create new land mass. These findings highlight that encouraging quasi-natural conditions through the widespread application of active sediment management measures has the potential to promote more sustainable outcomes for the GBM delta. Practical measures to promote include tidal river management, and appropriate combinations of cross-dams, bandal-like structures, and dredging.
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Affiliation(s)
- Md Munsur Rahman
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh.
| | - Anisul Haque
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Robert J Nicholls
- Tyndall Centre for Climate Change Research, University of East Anglia, Norwich, UK
| | - Stephen E Darby
- School of Geography and Environmental Science, University of Southampton, Highfield, Southampton, UK
| | - Mahmida Tul Urmi
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Md Maruf Dustegir
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Frances E Dunn
- Faculty of Geosciences, Utrecht University, the Netherlands
| | - Anika Tahsin
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Sadmina Razzaque
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Kevin Horsburgh
- Green Climate Fund, 175 Art center-daero, Yeonsu-gu, Incheon 22004, Republic of Korea
| | - Md Aminul Haque
- Water Resources Planning Organization (WARPO), Dhaka, Bangladesh
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8
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Latrubesse EM, Park E, Kästner K. The Ayeyarwady River (Myanmar): Washload transport and its global role among rivers in the Anthropocene. PLoS One 2021; 16:e0251156. [PMID: 33983980 PMCID: PMC8118563 DOI: 10.1371/journal.pone.0251156] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/20/2021] [Indexed: 11/30/2022] Open
Abstract
The Ayeyarwady (Irrawaddy) is the second largest river of Southeast Asia and one of the rivers with the highest load of suspended sediment delivered to the sea in the world. The Ayeyarwady is the lifeline of Myanmar which concentrates the majority of the population and GDP of the country. It is the main way of transport, a source of fluvial aggregates for development projects, hydropower, and the basin plays a major role in food supply and irrigation. Despite the Ayeyarwady ranking amongst the world’s largest rivers and its vital importance to Myanmar, scarce research has been undertaken to understand its morphodynamics and sediment transport regime. Current load estimates still heavily rely on the only systematic study of sediment transport dating back to the 19th century. Here, we provide a novel estimate for the recent washload sediment transport based on a field calibrated remote sensing model of surface suspended sediments concentrations. We show that the Ayeyarwady has likely become the river with the second or third largest delivery of washload to the sea in the world since it has so far been much less affected by damming compared to the vast majority of other rivers.
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Affiliation(s)
- Edgardo M. Latrubesse
- Graduate Program in Environmental Sciences-CIAMB, Universidade Federal de Goiás, Goiânia, Brazil
- * E-mail:
| | - Edward Park
- National Institute of Education and Asian School of the Environment, Nanyang Technological University, Singapore
| | - Karl Kästner
- Institute of Environmental Sciences, Brandenburg University of Technology, Cottbus, Germany
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9
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Abstract
Protecting against riverbank erosion along the world’s largest rivers is challenging. The Bangladesh Delta, bisected by the Brahmaputra River (also called the Jamuna River), is rife with complexity. Here, an emerging middle-income country with the world’s highest population density coexists with the world’s most unpredictable and largest braided, sand-bed river. Bangladesh has struggled over decades to protect against the onslaught of a continuously widening river corridor. Many of the principles implemented successfully in other parts of the world failed in Bangladesh. To this end, Bangladesh embarked on intensive knowledge-based developments and piloted new technologies. After two decades, successful, sustainable, low-cost riverbank protection technology was developed, suitable for the challenging river conditions. It was necessary to accept that no construction is permanent in this morphologically dynamic environment. What was initially born out of fund shortages became a cost-effective, systematic and adaptive approach to riverbank protection using improved knowledge, new materials, and new techniques, in the form of geobag revetments. This article provides an overview of the challenges faced when attempting to stabilize the riverbanks of the mighty rivers of Bangladesh. An overview of the construction of the major bridge crossings as well as riverbank protection schemes is detailed. Finally, a summary of lessons learned concludes the impressive progress made.
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10
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Dietrich M, Best KB, Raff JL, Ronay ER. A first-order geochemical budget for suspended sediment discharge to the Bay of Bengal from the Ganges-Brahmaputra river system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 726:138667. [PMID: 32320887 DOI: 10.1016/j.scitotenv.2020.138667] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/05/2020] [Accepted: 04/10/2020] [Indexed: 06/11/2023]
Abstract
The Ganges-Brahmaputra-Meghna (G-B) river system transports >1 × 109 t/yr of sediment, with an estimated 0.7 × 109 t/yr reaching the Bay of Bengal (BoB). This discharge represents a major input of sediment and associated elements to the global ocean, but quantification of the sediment-element mass reaching the BoB has yet to be fully explored. Published geochemical and suspended sediment data are used to calculate a first-order budget for the modern sediment supply of geochemical elements to the BoB. River profile bulk sediment-element concentrations are calculated based on suspended sediment and element measurements taken in the Ganges and Brahmaputra rivers. A Monte Carlo analysis is applied to account for variable sediment and geochemical contributions from each river. Results show that on average, the G-B system contributes ~5% of the global riverine discharge of solid-phase elements from sediment to the oceans. G-B sediments transport >10% of the global element supply of Hf and Zr. For others, like As and Cu, contributions from the G-B are <5%. Results also show that sediment reaching the BoB is relatively enriched in Hf, Zr, Th, REEs, Sn, and Bi, and majorly depleted in Na and Sr compared to UCC elemental concentrations. While limited by data availability and necessary simplifying assumptions, this study nevertheless provides a reasonable first-order budget for the modern discharge of solid-phase elements to the BoB. Insights from this work are significant for understanding the role of the G-B river system in global elemental cycling, and for providing a basis of comparison for future sediment-element discharge in light of rapid environmental change taking place in the region.
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Affiliation(s)
- Matthew Dietrich
- Department of Earth and Environmental Sciences, Vanderbilt University, 5726 Stevenson Center, 7th floor, Nashville, TN 37240, United States.
| | - Kelsea B Best
- Department of Earth and Environmental Sciences, Vanderbilt University, 5726 Stevenson Center, 7th floor, Nashville, TN 37240, United States
| | - Jessica L Raff
- Department of Earth and Environmental Sciences, Vanderbilt University, 5726 Stevenson Center, 7th floor, Nashville, TN 37240, United States
| | - Elli R Ronay
- Department of Earth and Environmental Sciences, Vanderbilt University, 5726 Stevenson Center, 7th floor, Nashville, TN 37240, United States
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11
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Liu K, Wang F, Li J, Tiwari S, Chen B. Assessment of trends and emission sources of heavy metals from the soil sediments near the Bohai Bay. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:29095-29109. [PMID: 31392613 DOI: 10.1007/s11356-019-06130-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Anthropogenic emission sources (mainly vehicular and industrial emission) are one of the major emission sources of the heavy metals in aquatic ecosystems which have significant potential to perturb the marine geochemistry and ecosystem as well as human life also. In the present study, we tried to investigate the accumulation of heavy metals (Zn, Cr, Ni, Cu, Pb, Co, As, Cd, and Hg) at two sediment cores near the Bohai Bay in Southern Tianjin and reconstruct their historical trends over the last hundred years to understand the impacts of anthropogenic activities. The concentration of Zn and Cr is found maximum than the other studied heavy metals. Results suggest that in the mid-twentieth century, the maximum concentrations of Zn, Cr, Ni, Cu, and Pb are mainly because of the opening of Dagang Oilfield which emits a huge amount of heavy metals into the environment. Source apportionment analysis has been carried out using positive matrix factorization (PMF) model which suggests three major emission sectors of heavy metals, i.e., coal combustion, manufacturing, and smelting dust, having different contribution 32%, 40%, and 28% respectively to the total heavy metal burden. Industrial emissions are found to be the major sources of Cr, Ni, and Co while Pb is mainly originated from the coal combustion. The risk assessment analysis shows the value of mean effects range median (ERM) quotients ~ 0.17 for the two sediment cores which suggest nearly 21% toxicity of the studied metals indicating towards the policymakers for the mitigation of air pollution surrounding Tianjin.
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Affiliation(s)
- Kun Liu
- Environmental Research Institute, Shandong University, Qingdao, 266237, China
| | - Fu Wang
- Tianjin Center, China Geological Survey (CGS), Tianjin, 300170, China.
- Key Laboratory of Muddy Coast Geo-environment, China Geological Survey, CGS, Tianjin, 300170, China.
| | - Jiwei Li
- Environmental Research Institute, Shandong University, Qingdao, 266237, China
| | - Shani Tiwari
- Environmental Research Institute, Shandong University, Qingdao, 266237, China.
| | - Bing Chen
- Environmental Research Institute, Shandong University, Qingdao, 266237, China
- Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China
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Dunn FE, Nicholls RJ, Darby SE, Cohen S, Zarfl C, Fekete BM. Projections of historical and 21st century fluvial sediment delivery to the Ganges-Brahmaputra-Meghna, Mahanadi, and Volta deltas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:105-116. [PMID: 29894869 DOI: 10.1016/j.scitotenv.2018.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/29/2018] [Accepted: 06/01/2018] [Indexed: 05/13/2023]
Abstract
Regular sediment inputs are required for deltas to maintain their surface elevation relative to sea level, which is important for avoiding salinization, erosion, and flooding. However, fluvial sediment inputs to deltas are being threatened by changes in upstream catchments due to climate and land use change and, particularly, reservoir construction. In this research, the global hydrogeomorphic model WBMsed is used to project and contrast 'pristine' (no anthropogenic impacts) and 'recent' historical fluvial sediment delivery to the Ganges-Brahmaputra-Meghna, Mahanadi, and Volta deltas. Additionally, 12 potential future scenarios of environmental change comprising combinations of four climate and three socioeconomic pathways, combined with a single construction timeline for future reservoirs, were simulated and analysed. The simulations of the Ganges-Brahmaputra-Meghna delta showed a large decrease in sediment flux over time, regardless of future scenario, from 669 Mt/a in a 'pristine' world, through 566 Mt/a in the 'recent' past, to 79-92 Mt/a by the end of the 21st century across the scenarios (total average decline of 88%). In contrast, for the Mahanadi delta the simulated sediment delivery increased between the 'pristine' and 'recent' past from 23 Mt/a to 40 Mt/a (+77%), and then decreased to 7-25 Mt/a by the end of the 21st century. The Volta delta shows a large decrease in sediment delivery historically, from 8 to 0.3 Mt/a (96%) between the 'pristine' and 'recent' past, however over the 21st century the sediment flux changes little and is predicted to vary between 0.2 and 0.4 Mt/a dependent on scenario. For the Volta delta, catchment management short of removing or re-engineering the Volta dam would have little effect, however without careful management of the upstream catchments these deltas may be unable to maintain their current elevation relative to sea level, suggesting increasing salinization, erosion, flood hazards, and adaptation demands.
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Affiliation(s)
- Frances E Dunn
- GeoData, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Robert J Nicholls
- Engineering and the Environment and Tyndall Centre for Climate Change Research, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Stephen E Darby
- Geography and Environment, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Sagy Cohen
- Department of Geography, University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Christiane Zarfl
- Department of Geosciences, University of Tübingen, Tübingen, Germany.
| | - Balázs M Fekete
- Department of Civil Engineering, The City College of New York, City University of New York, New York, USA.
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