Study of fine material in suspension in the estuary of the Loire and its dynamic grading

Gallenne, Bertrand

doi:10.1016/0302-3524(74)90016-4

Cited by 22 publications

(5 citation statements)

References 4 publications

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“…The Loire Estuary is a macrotidal system with a maximum tidal amplitude of ~6 m at the river mouth (Saint Nazaire; Fig. 1) and a water residence time estimated between 3 and 30 days during flood and low water discharge periods, respectively (Coynel et al, 2016;Gallenne, 1974). The Loire Estuary basin is highly industrialized and urbanized comprising (i) the metropole region of Nantes and Saint-Nazaire cities with its more than 800,000 inhabitants, (ii) the 4 th French seaport (Nantes-Saint-Nazaire harbour), (iii) one of the biggest French refinery of crude oil (Donges with a capacity of 11.5 million tons/year), (iii) the largest coal-fired thermal electricity production in France (Cordemais), and (iv) various industrial activities such as gas storage, aircraft industry, shipyards, etc.…”

Section: Study Areamentioning

confidence: 99%

Assessment of the metal contamination evolution in the Loire estuary using Cu and Zn stable isotopes and geochemical data in sediments

Araújo

Ponzevera

Briant

et al. 2019

Marine Pollution Bulletin

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In this work, a multi-elemental approach combining Cu and Zn stable isotopes is used to assess the metal contamination evolution in the Loire estuary bulk sediments. Elemental geochemical data indicate an increase of metal concentrations from the beginning of the industrial period peaking in the 1990s, followed by an attenuation of metal contamination inputs to the estuary. Zinc isotope compositions suggest a binary mixing process between Zn derived from terrigenous material and multi-urban anthropogenic sources. Copper isotope systematics indicate a single natural dominant source represented by weathered silicate particles from soils and rocks. This work demonstrates the applicability of Zn isotopes to identify anthropogenic Zn sources in coastal systems, even under a low to moderate degree of contamination. Further studies are required to constrain Cu sources and to elucidate possible effects of grain-size and mineralogy in the Cu isotope composition of sediment in the Loire estuary. Highlights ► Geochemical data and Cu and Zn isotopes were investigated in the Loire estuary. ► Cu and Zn isotope compositions of sediments vary in spatial and temporal scales. ► Zinc isotopes suggest a mixing process between terrigenous and urban sources. ► Cu isotopes indicate a natural dominant source represented by weathered material.

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Section: Study Areamentioning

confidence: 99%

Assessment of the metal contamination evolution in the Loire estuary using Cu and Zn stable isotopes and geochemical data in sediments

Araújo

Ponzevera

Briant

et al. 2019

Marine Pollution Bulletin

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“…Under such conditions, a dense suspension or even a fluid mud may be locally formed. Well known examples are found in the Gironde and Loire estuaries (Allen et al, 1974;Gallenne, 1974). High fresh water flow rates (high inputs of river-borne suspended matter) and to a lesser extent high discharges of waste water (domestic or industry) may also contribute to high turbidity values in zone 2-10 psu.…”

Section: Quantitative Aspects Of Suspended Sediments (Turbidity)mentioning

confidence: 99%

General description of the Scheldt estuary

Baeyens¹,

Eck²,

Lambert

et al. 1998

Trace Metals in the Westerschelde Estuary: A Case-Study of a Polluted, Partially Anoxic Estuary

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A general description of the Scheldt estuary, including the hydrology, the sediment transport, the productivity and the biodegradation with respect to their influence on the trace metal behaviour in the Scheldt estuary, is given.The river basin can be divided in several sections according to their morphological, hydrodynamical and sedimentary properties. The zone from km 78 to 55, which corresponds roughly with the salinity zone from 2 to 10 psu, is the zone of high turbidity, high sedimentation and of oxygen depletion, especially in the summer period. That area is called the geochemical filter because the solid/dissolved distribution of the trace metals is controlled by redox, adsorption/desorption, complexation and precipitation/coprecipitation processes. The sedimentation rate in that area is estimated at 280 Mkg y ,1 .In the downstream estuary the phytoplankton activity increases due to the restoration of oxygen and to the much lower turbidity values. That area is called the biological filter because incorporation of trace metals by the plankton communities lowers the trace metal concentrations during the productivity period, while transformation of metal species, especially observed with mercury, occurs during that period too.

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“…The sediment dynamics in the ETM exhibit significant difference among estuaries, depending on local topography, fluvial and tidal forcing, and sediment composition [1]. The formation mechanisms of the ETM, as reported by previous studies, can be attributed to estuarine circulation and residual current [2,3], tidal asymmetry [4,5], resuspension [4,6], stratification [7,8], flocculation [9,10] and sediment phase lag [11,12]. The Changjiang River Estuary (CRE), being the estuary of the largest river in China, is a mesotidal and partially mixed estuary with remarkable river discharges and strong tidal dynamics.…”

Section: Introductionmentioning

confidence: 73%

Seasonal Estuarine Turbidity Maximum under Strong Tidal Dynamics: Three-Year Observations in the Changjiang River Estuary

Hua

Huang

Wang

et al. 2020

Water

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The estuarine turbidity maximum (ETM) under strong tidal dynamics (during spring tides) was investigated along the Deepwater Navigation Channel (DNC) in the North Passage (NP) of the Changjiang River Estuary (CRE) in wet and dry seasons of 2016, 2017 and 2018. The observed water current, salinity, stratification and suspended sediment concentration (SSC) were illustrated and analyzed. Results show that the SSC was lower in wet seasons than dry seasons in 2016 and 2017 because of the weak influence of typhoons before observations in wet seasons. On the contrary, the SSC was higher in the wet season than the dry season in 2018 because of the strong influence of typhoons in the wet season. Our observations challenged the common perspective that SSC in the NP is higher in wet seasons than dry seasons, because the magnitudes of SSC were found to be easily influenced by strong winds before observations. The along-channel distribution of high SSC was determined by the location of salt wedge, and consequently, the ETM was further upstream in dry seasons than wet seasons. The observed SSC was more concentrated in lower water layers in wet seasons (“exponential” profile) than dry seasons (“linear” profile). This seasonal difference of vertical SSC was related to the flocculation setting velocity influenced by temperature rather than the weak stratification during spring tides. Moreover, on the basis of the net water/sediment transport and flux splitting, large river discharge and a low-SSC condition could reduce siltation in the middle DNC. The former vanished the convergence of water transport, and the latter reduced landward tidal pumping sediment transport. Sediment trapping and siltation in the dry seasons occurred in the seaward segment of the upper reach because of the decrease in the river discharge.

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Study of fine material in suspension in the estuary of the Loire and its dynamic grading

Cited by 22 publications

References 4 publications

Assessment of the metal contamination evolution in the Loire estuary using Cu and Zn stable isotopes and geochemical data in sediments

Assessment of the metal contamination evolution in the Loire estuary using Cu and Zn stable isotopes and geochemical data in sediments

General description of the Scheldt estuary

Seasonal Estuarine Turbidity Maximum under Strong Tidal Dynamics: Three-Year Observations in the Changjiang River Estuary

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