Untitled

Saxena, Devanshi; Joos, Pieter; Grieken, R. Van; Subramanian, V.

doi:10.1023/a:1014821906600

Cited by 22 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…whereas C n is the measured concentration of the element 'n' in the pelitic sediment fraction (v2 mm) and B n is the geochemical background value in fossile argillaceous sediment. Since short dated sedimentary cores, which provide a recent historical record of events occurring in the watershed of the Yamuna River, 24 these would enable an estimation of both the background levels and the changes in input of an element over an extended period of time. Background levels may be regarded as the levels that exist on top of which anthropogenic materials have been added.…”

Section: Resultsmentioning

confidence: 99%

“…This time interval also represents the intensive agricultural and industrial activity in this river basin, considered one of the most densely populated regions in the Indian sub-continent. Since 137 Cs was also used in the determination of sedimentation rates 24 that works out to be in the range 2-4 cm per year, the upper time interval is 1993. The present day mercury levels as shown in Table 1 in combination with Table 3 clearly suggests that the supply of mercury to the river system via the sediment and soil erosion has been significantly increasing in recent times.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Nature of distribution of mercury in the sediments of the River Yamuna (tributary of the Ganges), India

Subramanian

Madhavan

Saxena

et al. 2003

J. Environ. Monitor.

Self Cite

View full text Add to dashboard Cite

Suspended Particulate Matter (SPM), surface (bed sediments) and short length cores of sediments collected from the largest tributary of the river Ganges, namely the river Yamuna, were analysed for total mercury as well as its fractionation in various size and chemical sites in the sediments following standard procedures. Also, attempts were made to determine the vertical distribution in sediments in relation to the recent timescale of a few decades. Our observations indicate that the SPM in general showed higher levels of total mercury compared to the surface sediments while at places the enhancement could be by a factor of 10, say around 25 microg g(-1) in the downstream region that integrates the industrial midstream and agricultural downstream terrain near its confluence with the Ganges. Surface sediments in the upstream direction near the Himalayan foothills and SPM in the lower reaches showed significant high Index of Geoaccumulation (Igeo) as defined by Müller. Size fractionation studies indicate that the finer fraction preferentially showed higher levels of mercury while in the lower reaches of the river, the total mercury is equitably distributed among all size fractions. The proportion of the residual fraction of mercury in relation to mobile fractions, in general decreases downstream towards its confluence with the Ganges river. In sediment cores, the vertical distribution show systematic peaks of mercury indicating that addition of this toxic metal to the aquatic system is in direct proportion to the increase in various types of human activities such as thermal power plants, land use changes (urbanisation) in the midstream region and intensive fertiliser application in lower reaches of this vast river basin.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Nature of distribution of mercury in the sediments of the River Yamuna (tributary of the Ganges), India

Subramanian

Madhavan

Saxena

et al. 2003

J. Environ. Monitor.

Self Cite

View full text Add to dashboard Cite

show abstract

“…At low flow velocity, charcoal fragments are transported by localized rolling over bedforms, while particles in suspension are transported toward the overbank region (Figure 6c) (Nichols et al., 2000). The low‐velocity region of the YSB experiences increased sediment deposition and development of overbank components (Saxena et al., 2002), facilitating an extended period of inundation in the floodplain. Under such conditions, increased settling of the charcoal fraction.…”

Section: Discussionmentioning

confidence: 99%

“…During the monsoon period, the lowland YSB experiences significant variation in sediment deposits due to factors such as high sediment fluxes, discharge rate, free space availability, and regional slope (Saxena et al., 2002). Charcoal accumulation in the floodplain is mainly associated with inundation after active flooding events rather than a continuous process seen in bedload sediments.…”

Section: Discussionmentioning

confidence: 99%

Hydrogeomorphic Response of Charcoals During River Transits and Its Impact on the Carbon Cycle

Roy,

Baidya,

Jain

2023

JGR Earth Surface

View full text Add to dashboard Cite

Natural or anthropogenic‐induced biomass burning produces large amounts of charcoals, which enter riverine or lacustrine systems mostly via surface runoff processes. Charcoal storage and cycling within large riverine systems can play a crucial role in mediating long‐term carbon sink across transient reservoirs, thereby influencing the global carbon budget. However, natural processes governing the transport and storage of charcoal particles in large terrestrial reservoirs such as the Indo‐Gangetic region still remain unknown. To understand charcoal movement and accumulation across upland and lowland transient reservoirs, we characterized spatial distribution and morphology of different charcoal forms (>125μm and <125μm) from bedload and floodplain sediments of the Yamuna sub‐basin (YSB), India. Both >125μm and <125μm charcoal forms in bedload and floodplain sediments did not exhibit similar spatial distribution patterns, indicating segregation of charcoal particles influenced by variable flow regimes. Attrition with sediments breaks down fragile charcoals (leaves) quickly compared to the woody forms, resulting in dominant woody microforms in transient deposits. Higher stream power and limited stable bedform development in upland mountainous regions restrict charcoal storage. During lowland riverine transits, reduced stream power conditions allow increased floodwater inundation and finer clay substrate availability, facilitating an exponential increase in charcoal storage. However, increased discharge from peninsular rivers into the YSB lead to erosion and redistribution of sediment, including charcoal particles, and reduced charcoal storage in lowland transient areas. Such diverse dispersal pathways and fate of charcoal particles across riverine transits highlight the influence of regional hydrogeomorphic processes on the overall carbon cycle within transient reservoirs.

show abstract

“…137 Cs was introduced into the global environment as a result of nuclear weapons testing performed after the 1950s, the Chernobyl accident in 1986, and recently the accident in the Fukushima Dai-Ichi nuclear power plant in 2011 [1][2][3]. It is probably the most frequently used anthropogenic radionuclide for monitoring environmental processes [4][5][6]. It is also the most represented anthropogenic gamma emitter in marine environments in which it is especially relevant due to its long residence time.…”

Section: Introductionmentioning

confidence: 99%

137Cs Sediment Profiles as a Tracer of Marine Sedimentation Processes in a Semi-Enclosed Bay Affected by Anthropogenic Releases—Example of Kaštela Bay (Adriatic Sea, Croatia)

Mikelić

Cukrov

Oreščanin

et al. 2022

Water

View full text Add to dashboard Cite

Kaštela Bay was taken as a model to study sedimentation processes using the vertical sediment profiles of 137Cs massic activities. The aim was to distinguish the sedimentation conditions in different parts of the Bay and to partly determine the pathways of terrigenous input into the Bay. The purpose was to demonstrate that 137Cs profiles are applicable in differentiating sedimentation processes. It was found that mostly continuous, undisturbed sedimentation takes place in the central and south parts of the Bay; the sedimentation conditions in the west part of the Bay are more complicated. The west part is characterised by the extremely slow sedimentation of the coarse-grained sediment or even by erosion and selective resuspension of the fine-grained particles followed by resedimentation in other parts of the Bay. It was also observed that the upper 10 cm of the sediment is the most exposed to homogenisation. The strong influence of the Jadro River and anthropogenic activities in the east part of the Bay are reflected in the higher 137Cs activities, strong sediment mixing, and increased sediment input. This study shows that the 137Cs profiles can provide comprehensive insights for the whole study region when a sophisticated sampling layout is deployed. The results of the study are applicable to other aquatic environments with comparable processes and sedimentary environments.

show abstract

Untitled

Cited by 22 publications

References 36 publications

Nature of distribution of mercury in the sediments of the River Yamuna (tributary of the Ganges), India

Nature of distribution of mercury in the sediments of the River Yamuna (tributary of the Ganges), India

Hydrogeomorphic Response of Charcoals During River Transits and Its Impact on the Carbon Cycle

137Cs Sediment Profiles as a Tracer of Marine Sedimentation Processes in a Semi-Enclosed Bay Affected by Anthropogenic Releases—Example of Kaštela Bay (Adriatic Sea, Croatia)

Contact Info

Product

Resources

About