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Cadmium contamination of three bivalve species (oysters, cockles and clams) in Nord Médoc salt marshes (Gironde estuary, France): Geochemical survey and metal bioaccumulation kinetics

Authors:
Magalie Baudrimont at University of Bordeaux
Magalie Baudrimont
Jörg Schäfer at University of Bordeaux
Jörg Schäfer
V. Marie
V. Marie
V. Marie
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Régine Maury-Brachet at Université Bordeaux-I
Régine Maury-Brachet
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Abstract and Figures

A historical Cd pollution of the Lot-Garonne River system (France) bas led to the contamination of sediment and water of the Gironde Estuary. In spite of the decrease of fluvial Cd inputs since the early 90ies, Cd concentrations in the Gironde oysters remain higher than European norms (5 μ\mug.g−1^{-1} dry mass) and the “zone D” classification of the estuary prohibits bivalve production and harvesting for human consumption. A geochemical survey in salt marshes used for aquaculture (crustaceans) has been conducted in order to assess the heavy métal contamination level in these systems periodically alimented by the Gironde water, accompanied by caging experiments on three bivalve species of economical interest: oysters (Crassostrea gigas), cockles (Cerastoderma edule) and clams (Ruditapes philippinarum) to study heavy metal accumulation in these organisms. Distribution of heavy metals in this system is controlled by biogeochemical processes and is independent of routine water management. Contamination levels in the studied species indicate the high accumulation of Cd by oysters. On the other hand, Cd concentrations in benthic species, such as cockles and clams, are clearly lower than European safety limits for human consumption.
Map of the fluvio-estuarine continuum of the Gironde, affected by historic polymetallic pollution (*, former Zn ore treatment plant). The experimentation site in the Nord Médoc salt marshes near the estuary mouth is represented by a black dot.
Map of the fluvio-estuarine continuum of the Gironde, affected by historic polymetallic pollution (*, former Zn ore treatment plant). The experimentation site in the Nord Médoc salt marshes near the estuary mouth is represented by a black dot.
… 
Dissolved Cd, Cu, Zn, Hg T and Hg R in the breeding basin
Dissolved Cd, Cu, Zn, Hg T and Hg R in the breeding basin
… 
Seasonal variations of the major physico-chemical parameters temperature, salinity, dissolved O 2 and pH in the breeding basin throughout the whole experiment. Manual measurements at the surface (~10 cm depth) are represented by crosses and open triangles, representing different operators. Full lozenge symbols represent selected multiprobe data (~50 cm depth) corresponding to the regular hour of manual measurements.
Seasonal variations of the major physico-chemical parameters temperature, salinity, dissolved O 2 and pH in the breeding basin throughout the whole experiment. Manual measurements at the surface (~10 cm depth) are represented by crosses and open triangles, representing different operators. Full lozenge symbols represent selected multiprobe data (~50 cm depth) corresponding to the regular hour of manual measurements.
… 
Example of multiprobe data (one measurement per hour) showing daily variations of major physico-chemical parameters (a) temperature, salinity, dissolved O 2 concentration and (b) O 2 saturation and pH at ~50 cm depth from July 26 to September 12, 2000. Graduations on the time axis represent 12:00 in Universal Time (i.e. 14:00 in European Summer Time) for the respective day.
Example of multiprobe data (one measurement per hour) showing daily variations of major physico-chemical parameters (a) temperature, salinity, dissolved O 2 concentration and (b) O 2 saturation and pH at ~50 cm depth from July 26 to September 12, 2000. Graduations on the time axis represent 12:00 in Universal Time (i.e. 14:00 in European Summer Time) for the respective day.
… 
Kinetics of growth and Cd bioaccumulation for juveniles of oysters C. gigas. Growth is represented by the dry weight of the shell (a) and of the whole soft body (b). Cd bioaccumulation is expressed as concentrations in relation to dry weights (c) and burdens (d). The histograms represent average values and standard errors (n=5). The letters above the histograms illustrate the significant differences between the mean values, as a result of the LSD comparison test.
+2
Kinetics of growth and Cd bioaccumulation for juveniles of oysters C. gigas. Growth is represented by the dry weight of the shell (a) and of the whole soft body (b). Cd bioaccumulation is expressed as concentrations in relation to dry weights (c) and burdens (d). The histograms represent average values and standard errors (n=5). The letters above the histograms illustrate the significant differences between the mean values, as a result of the LSD comparison test.
… 
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Cadmium contamination of three bivalve species (oysters, cockles
and clams) in Nord Médoc salt marshes (Gironde estuary, France) :
Geochemical survey and metal bioaccumulation kinetics
M. Baudrimont, J. Schäfer\ V. Marie, R. Maury-Brachet, C. Bossy1, G. Durrieu,
A. Palvadeau, E. Maneux\ A. Boudou and G. Blanc1
Laboratoire d'Écophysiologie et Écotoxicologie des Systèmes Aquatiques, LEESA,
Université de Bordeaux I, UMR 5805 du CNRS, EPOC, place du Dr. Peyneau, 33120 Arcachon,
France
1 Department of Geology and Oceanography, DGO, Université de Bordeaux I,
UMR 5805 du CNRS, EPOC, avenue des Facultés, 33405 Talence cedex, France
Abstract : A historical Cd pollution of the Lot-Garonne River system (France) bas led to the contamination of
sediment and water of the Gironde Estuary. In spite of the decrease of fluvial Cd inputs since the early 90ies, Cd
concentrations in the Gironde oysters remain higher than European norms (5 pg. g-1 dry mass) and the " zone D "
classification of the estuary prohibits bivalve production and harvesting for human consumption. A geochemical
survey in salt marshes used for aquaculture (crustaceans) has been conducted in order to assess the heavy métal
contamination level in these systems periodically alimented by the Gironde water, accompanied by caging
experiments on three bivalve species of economical interest : oysters (Crassostrea gigas), cockles (Cerastoderma
edule) and clams (Ruditapes philippinarum) to study heavy metal accumulation in these organisms. Distribution of
heavy metals in this system is controlled by biogeochemical processes and is independent of routine water
management. Contamination levels in the studied species indicate the high accumulation of Cd by oysters. On the
other hand, Cd concentrations in benthic species, such as cockles and clams, are clearly lower than European safety
limits for human consumption.
1. INTRODUCTION
A historical Cd pollution of the Lot and Garonne Rivers (south west France), originated from discharge in
the industrial basin of Decazeville, has led to the contamination of sediment and water of the Gironde
Estuary resulting in high Cd accumulation in oysters (Crassostrea gigas) [1]. Thus, the Gironde has been
classifie " zone D " (French law, Arrêté du 21/07/1995) and consequently bivalve production and
harvesting in the estuary for human consumption is prohibited.
In spite of the decrease of fluvial Cd inputs since the early 90ies [1], Cd concentrations in the
Gironde oysters remain higher than European norms, especially since. April 2002, when new, lower safety
limits were established (5 ig. g-1 dry mass ; CE N'466/2001, [2]). The interdiction of bivalves production
in the Gironde estuary restricts the aquaculture in the Nord Médoc sait marshes to kuruma prawn
(Penaeus japonicus) production. However, the presence of an important natural population of cockles
(Cerastoderma edule) in these systems has led the local professional association (CURUMA) to conduct
an interdisciplinary study coupling geochemical and ecotoxicological assessment, in order to enhance the
economical potential of the Nord Médoc sait marshes by benthic bivlaves production. This survey has
been conducted during 15 months in order to quantify the heavy metal contamination in three different
sait marshes, in condition of prawn production or without any crustaceans in the basins, along witb a
study on metal bioaccumulation in three bivalve species of economical interest : oysters (Crassostrea
gigas), cockles (Cerastoderma edule) and clams (Ruditapes philippinarum). Bivalves are known to
1 iC
accumulate large quantities of metals by their ventilation activity for nutritional and respiratory purposes,
and couid in this way indicate thé présence ofbioavaiiabte metats in thé basins. Data base analyses were
expected to aïlow the determination of pathways, dynamics and levels of contamination, especially of Cd.
The presented results were obtained in the " Bleu Médoc " basin, where prawn production was suspended,
but water management was continued.
2. STUDY AREA, MATERIALS and METHODS
2. 1 Study area
The Nord Médoc sait marshes (south west France, Fig. 1) are located near the mouth of the Gironde
estuary which is one of the major European estuaries (riverine water discharge : 34 x 109 rn3. yeaf', [1]).
These salt marshes, formerly constructed for salt production, are now used for aquaculture and kuruma
prawn (Panaeus japonicus) production. Typical basin sizes are 300x60 m with depths between 0. 7 to
1.
2 m. Brackish water supply for the breeding basins is realized by controlled input of estuarine water at
high tide, transporting nutrients but as polluants into the basins.
Gironde Estuary
Nord Médoc
salt niarshes 1
zizi
alo'rkau Dordogne river
aronne River
LoiRîverDecazevilleRiou-,Vort 50 km
River
Figure 1. Map of the Gironde Estuary and the Nord Médoc salt marshes (France).
2. 2 Geochemical survey
The geochemical characterization of the breeding basins is based on a 15 months observation of two types
of geochemical parameters :
Physico-chemical parameters (T°, salinity, dissolved oxygen concentrations and pH) were measured
every hour using automatic multiparameter probes (Hydrolab), which were installed at-30 cm above the
sediment surface. These measurements were completed by manual measurements at the water surface 2-4
times per week. Probes were checked, cleaned and calibrated each month, when stored data were
recovered. Particulate heavy metal concentrations in the sediment, in suspended particles (recovered by
pumping/centrifugation [3] and collected by sediment traps) and dissolved concentrations in the water
column were analysed by ICP-MS. Matrix separation for estuarine water analysis was done by
liquid solid extraction [3]. The applied analytical methods were continuously quality checked by analysis
of international certified reference materials (PACS-1, CRM-320, SLRS-3, SLRS-4, SLEW-2). Accuracy
was within 10% and precision was within 5 % for concentrations 10 times higher than detection limits.
2. 3. Ecotoxicological studies
Jointly to the geochemical survey, three bivalve species were transplante in the basins during 10 months
(from May 2000 to March 2001), either suspended in the water column for oysters (Crassostrea gigas) in
bags, or at the water/sediment interface for cockles (Cerastoderma edule) and clams (Ruditapes
philippinarum) in cages. Oysters were juveniles (8 mm of shell length) and originated from the Ile de Ré
(France), cockles and clams were one-year old, and were respectively indigeneous and imported from
Italy. Every 40 days, individuals were collected from each cage or bag. 5 sub-amples were used for
analysis of growth (size of the shell and total dry mass of the soft body-60°C during 48h) and heavy
metal concentrations after digestion step (3 hours in high purity nitric acid at 95°C) by Atomic
Absorption Spectrophotometry (AAS Varian 400). Validity of the analytical method was checked
periodically using biological standard relerence material (TORT-2, DORM-2-CNRC, Ottawa, ON,
Canada).
3. RESULTS and CONCLUSIONS
The evolution of the physico-chemical parameters as temperature dissolved 02 and pH show distinct daily
variations reflecting photosynthesis and respiration, whereas salinity varies with basin alimentation,
evaporation and precipitation (Fig. 2). In summer, high water temperatures and intense biomass
production and degradation result in very low dissolved 02 concentrations, reaching minimum values of
<40 % of 02-saturation at 30 cm above the sediment in the early morning before sunrise. Vertical 02
profiles show that hypoxia increases with depth, causing anoxie conditions ( 1% 02-saur. ; data not
shown) at the sediment surface.
r 9 Although in the breeding basins high and very
-'- ! 30 8 6 variable Cd concentrations occurred in the
te ierature salinli'ty 8, 6
r'dissolved phase and in SPM recovered by the
6 6 20-v 8, 2 pumping/ centrifugation method [3], the particles
O pH, ^ collected in sediment traps and basin sediments
E : Si 7, 8 show low Cd concentrations similar to the local
fî 10- background (<0. 5 mg. kg-1). This suggests that
7, 4
trapped particles are similar to those in the upper
E 0 27 sediment layers. Current velocities were too low
7/257/30 8/4 8/9 8/148/198/248/29 913 9/8 (<0. 1 m. s-') to affect the geochemical
composition by grain size segregation.
Figure 2. Daily variations of T, pH, 02 and
salinity in the Therefore, the different concentrations in
breediiig basin. centrifuged aiid trapped particles are attributed to
dissolution processes in the redox gradient (early
0, 5 1 Cd sr'1 30 diagenesis). As the trapped material was sampled
0, 4 I 25 monthly, kinetics
_... Ï dissolution appear to be high, leading to the
rapid release of particulate metals into the water
R 0, 2 / ` " 15 i ; colurnn. Here, the metals can be adsorbed onto
0,
2 15
Q, >, 0 SPM or be stabilized within the dissolved phase
0'l....... 10 by complexation. As there is no apparent relation
00 1... 5 between dissolved Cd concentrations and salinity'514100 7/4/00 913/00 11/3/00 113/01 3/5/01 5/5/01 7/5/01 9/4/01 in the
breeding basins (Fig. 3), concentrations,
distribution and partition of heavy metals in this
Figure 3. Dissolved Cadmium concentrations in the system appears to be controlled mainly by
breeding basin
vs.
salinity biogeochemical processes and, to a lesser extent,
by water management.
Juveniles of oysters (Crassostrea gigas) showed a rapid and important increase of soft body dry weight
with respect to time, especially during spring and summer, characterized by important phytoplanctonic
algae supplies (Fig. 4). In winter, the weight of the oysters stabilized, in relation to the decrease of food
supplies and the change in climate conditions. Growth was then clearly correlated with abiotic factors
(temperature, dissolved 02 and pH) measured in the water column of the basin. For Cd concentrations, a
significant and quasi-linear increase was observed with time, reaching very high values at time T8 (March
2001), near 25, 000 ngCd/g (dw), corresponding to 5 times the authorized level for human consumption.
The comparison of Cd accumulation in the three species at time T5 (December 2000) showed
marked differences between contamination levels (Fig. 6), indicating the high impact of Cd on Oysters,
able to filter large quantities of water for respiratory and nutritional purposes. On the other hand, benthic
species, such as cockles (Cerastoderma edule) and clams (Ruditapes philippinarum), did not present
significant heavy metal contamination, always under the human consumption limit. These results are
consistent with low metal concentrations measured in thé basin sediment and in trapped particles, on the
contrary of ponctually high dissolved and particulate Cd levels in the water column.
0,5rtl:g'EType±1,96E-Typ.
a H. M'Err-Typ. 30000
t, . . Typ.-r-T
? " MMg< OtvMtt [° ! [J
3. ! 24000-r-r !
3 8 avetage ta avearge i 0
r 0, 4 i T ; 1 a 1
24000
0,3 18000
'B. s 11
0
z i
., P 0, 1 6000 1= = 1
. = !TO TI T2 T3 T4 TS T6 T7 T8 TO Tl T2 T3 T4 T5 T6 T7 T8
Sampling point Sampling point
Figure 4. Chair
mass
(a) and Cd accumulation levels (b) in the soft
parts
of Oysters. TO
to T8 are
the successive sampling
times of
one
caging experiment.
Cd (mg. kg'') Cd (mg. kg ")
0 1 2 3 0 1 2 3 24000 : . : Type----
5117100 1 average
2 [21/01 20000 0-5
$PM
-) ;..'______'j ?
2/21/01 SPM 0-5 16000
25-30 cn
9/26/00 X'B- ! 3
; Tr'ip !F'IZUUU
0-5
9126/00 15-20 Il February 2001
11/22/00
25-30 8000
2/21/01 5 pg/g (dw)
..............................................................................
0-5 4000
519/01 15-20
Cockles Clams Oysters
Figure 5.
Cd
contents
in SPM,
trap
sediments and Figure 6. Cadmium concentrations in the 3 studied bivalve
sediment. Dashed lines represent regional background species compared with European safety limits.
values and full lines polluted harbour sediments [5].
These results allowed CURUMA to obtain the safety classification of the Eau Médoc salt marshes
to
produce cockles and clams since January 2003, that enhances the economical potential of this region.
Acknowledgements
This work
was
funded by FEDER (PESCA),
« Conseil
Général de la Gironde
», « Agence
de l'Eau Adour-Garonne
M,
« District
de
la Pointe du Médoc
», «
Direction Régionale des Affaires Maritimes
» and by a Marie Curie fellowship (European
Community
program
" Energy, Environment and Sustainable Development "
; EVKI-CT-2000-5003. The study
was
supported
by GIS ECOBAG. The
project
was
conducted by the
"
Mission
de
valorisation-Breve » of University
Bordeaux 1. We thank
V. Roques-Duflo, H. Bouillard, Y. Lapaquellerie, N. Maillet and B. Etcheverria for technical support.
References
[11 Schäfer J., Blanc G., Lapaquellerie Y., Maillet N., Maneux E. and Etcheber H., illar. Chem., 79 (2002) 229-242.
[2j Schâfer, J. et Blanc. G. Sci. Tot. Environ., 298 (2002) 103-ilS.
[3] Kingston, H. M., Barnes, I. L., Brady, T. J. and Rains, T. C. Anal. Chem., 50 (1978) 2064-2070.
[4'l- Résudtats de la survei ! lance de la qualité du milieu marin littoral, IFREMER, RNO, 200 i.
iSì GEODE, Bilan d'activiíé {1996).
... In the present work, the effect of CdCl 2 contamination on the MTLP, MDA, Cd bioaccumulation and protein concentrations was determined under the laboratory conditions. Indeed the most published data on metals in Cerastoderma concerned in situ studies (Baudrimont et al. 2003;Machreki-Ajmi & Hamza-Chaffai 2006). However, in polluted environments, animals are generally exposed to a mixture of different metals. ...
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Article
  • Jan 2010
Les estuaires sont des systèmes hautement dynamiques où interagissent des processus biogéochimiques complexes qui influent sur le devenir de la matière organique et non organique. La confrontation des eaux fluviales et marines induit des changements rapides des principaux facteurs structurant la distribution des organismes vivants et gouvernant la spéciation de certains éléments traces entre phase particulaire et dissoute, ex : gradient de salinité, teneurs en matières en suspension (MES). Ce travail vise à étudier l'estuaire de la Charente, principal fleuve influançant le bassin de Marennes-Oléron (première zone ostreicole française) afin (i) de caractériser la structure de la communauté zooplanctonique en relation avec les paramètres environnementaux, (ii) le fonctionnement de la base du réseau trophique de l'estuaire (identification des sources de matière organique exploitée par les organismes zooplanctoniques et suprabenthiques) et (iii) d'établir un état de contamination par les métaux des compartiments biotiques. L'estuaire de la Charente se distingue par des concentrations en MES extrêmement élevées, présentant néanmoins une contribution importante de la matière organique (efflorescence phytoplanctonique printanière en zone mésohaline et production microphytobenthique). La zone de turbidité maximale semble correspondre à un écotone qui contrôle les flux de matière organique et la distribution des organismes. Le mélange physique des particules issues des systèmes dulcicoles et marins adjacents à l'estuaire avec cette forte charge de matériel resuspendu conduit à une homogénéisation des signatures isotopiques et métalliques particulaires en été et automne le long du gradient de salinité. Les quatre assemblages zooplanctoniques identifiés sont structurés spatialement par la salinité et la concentration en MES et temporellement par les variations de température et de débit fluvial. Malgré la dominance quantitative du matériel détritique au sein du pool de matière organique particulaire (MOP), il semble que les 5 taxons planctoniques ou suprabenthiques dominants étudiés (Eurytemora affinis, Acartia spp., Daphnia spp., Neomysis integer, Mesopodopsis slabberi) présentent une sélectivité importante vis-à-vis de sources primaires distinctes. Cette succession spatio-temporelle d'espèces sélectives conduit à une multiplication des flux trophiques et semble ainsi optimiser à l'échelle annuelle l'exploitation de la MOP disponible. Les concentrations en Cd, Cu, Hg, Pb, V et Zn ont par ailleurs été mesurées dans près de 40 taxons estuariens (zooplancton, benthos, poissons). Malgré des concentrations en métaux dissous et particulaires plus faibles que dans les grands estuaires européens subissant une pression anthropique importante (Seine, Gironde), les niveaux de contamination mesurés dans les différents compartiments biotiques semblent globalement équivalents. Les évènements brefs (crue hivernale, efflorescence phytoplanctonique printanière) altèrent toutefois fortement ce schéma général en modifiant les sources primaires de matière organique disponibles et les concentrations métalliques particulaires (Cd notamment).
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Groundwater contributions to metal transport in a small river affected by mining and smelting waste
Article
  • Sep 2007
  • WATER RES
The Riou Mort watershed, strongly affected by former coal mining and Zn ore treatment, has been the major source of the historical polymetallic pollution of the Lot-Garonne-Gironde fluvial-estuarine system. Two decades after the end of ore treatment, the former industrial area still contributes important amounts of metals/metalloids from various, partly unidentified, sources to the downstream river system. This study presents the high spatial variability of metal/metalloid (Cd, Zn, As, Sb, U, V) concentrations in water and suspended particulate matter (SPM) from eight observation sites during a short, intense flood event. Despite important dilution effects, the observed concentration levels at the different sites suggested additional Cd and Zn inputs, probably from polluted groundwater. This formerly unknown metal source was then localized and characterized by sampling water and SPM along two longitudinal profiles during different hydrological situations. Groundwater inputs of "truly dissolved" (<0.02 microm) Cd and Zn occurred along approximately 200 m, contributing 43% and 28% to the total annual (2004) Cd and Zn fluxes in the Riou Mort River. The estimated groundwater concentrations of Cd and Zn (2500-6700 and 83,000-170,000 microg l(-1), respectively) in the source zone were consistent with values measured in samples from the near aquifer (5400-13,000 and 200,000-400,000 microg l(-1)). The present work induced concrete remediation actions (pumping and treatment of the polluted groundwater), that are expected to strongly reduce dissolved Cd and Zn emissions into the Riou Mort River.
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Sediment trap dynamics and calibration: a laboratory evaluation.
Article
Full-text available
  • Jan 1980
The flow dynamics and particle trapping characteristics of several designs of sediment traps were investigated using dye, sea-water, and deep-sea lutite in a recirculating flume and fish tank at velocities of 0, 4, and 9cm/sec. Particles are collected through a process of fluid exchange rather than falling freely into a trap. Cylinders trap particles in the closest agreement with the sediment depostion rate in the flume. Funnels generally undertrap, but their efficiency may be improved by constructing a baffle at the top of the funnel. Containers with narrow mouths and wide bodies consistently overtrap at an unpredictable rate of many times the actual vertical flux of particles. -from Author
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Intercomparaison de méthodes d'échantillonnage des matières en suspension en milieu fluvial : application à la mesure de laconcentration en micropolluants métalliques
Article
Full-text available
  • Jan 1999
Le but de l'etude decrite dans le present article est de comparer plusieurs methodes de prelevement de matieres en suspension (centrifugation, prelevement sequentiel d'eau et filtration, filtration sur cartouches, trappes immergees, decanteur emerge (dit MIM), afin d'evaluer la representativite de l'echantillonnage et la faisabilite des techniques testees pour l'evaluation des concentrations en micropolluants metalliques particulaires. A cette fin, deux campagnes d'intercomparaison ont ete organisees en aval de la centrale nucleaire de Nogent/Seine, au cours de deux periodes hydrologiques contrastees. La representativite des diverses techniques mises en jeu a ete testee par le suivi de la concentration totale en divers metaux traces (Cu, Zn, Fe, Mn), par la mesure des spectres granulometriques des echantillons recueillis et par l'evaluation de la speciation biogeochimique des metaux particulaires.
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Food sources of an infaunal suspension-feeding bivalve Cerastoderma edule in a muddy sandflat of Marennes-Oléron Bay, as determined by analyses of carbon and nitrogen stable isotopes
Article
Full-text available
  • Oct 1999
Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oleron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean δ13C value of -22.2 ± 1.1‰ (n = 19). Benthic primary producers on Ronceles-Bains tidal flats had δ13C values distinct from that of the POM: microphytobenthos (-16.0 ± 0.6‰), the macroalgae Enteromorpha compressa (-17.6 ± 2.8‰), Fucus serratus (-17.4 ± 2.6‰), Fucus vesiculosus (-18.5 ± 1.6%), Phorphyra umbilicalis (-19.7 ± 0.5‰), Ulva rigida (-14.7 ± 2.0‰) and the seagrass Zostera noltii (-11.1 ± 1.0‰). Mean δ15N values of all macroalgae species ranged from 7.6 ± 1.3 to 8.9 ± 1.0‰, while those for microphytobentbos, POM and seagrass were 5.3 ± 0.8, 5.0 ± 0.9 and 6.5 ± 1.3‰, respectively. The mean δ13C value of spat (-15.3 ± 0.8‰) and juvenile cockles (-15.7 ± 0.7‰) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 ± 1.2‰). The δ15N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 ± 0.9‰ for 0-group and 8.4 ± 1.1‰ for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: microphytobenthos and POM. Seasonal variations in δ13C values reflect a higher dependence of adult cockles on POM variability while spat and juveniles are more closely linked to microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.
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Cadmium pollution in the Gironde estuary[La pollution en cadmium de l'estuaire de la Gironde]
Article
  • Jan 1988
In this study characteristics and origin of Cd pollution in the Gironde estuary are described. Cd mainly originates from the industrial Decazeville zone in the Lot drainage basin. At the upper part of the estuary Cd is associated with suspended material. Downstream is dissolves and large amounts of Cd are concentrated by oysters of the natural beds of the Estuary mouth. -English summary
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Influence of the Gironde estuary outputs on cadmium concentrations in the coastal waters: Consequences on the Marennes-Oléron bay (France)
Article
  • Dec 2000
  • Oceanol Acta
The Gironde, an estuary in Southwestern France, has been highly contaminated by cadmium for many years, and the results of the French mussel watch suggest that this contamination is not restricted to the estuary, but could be responsible for relatively high levels of Cd in the oysters from the Marennes-Oléron bay located nearby. This hypothesis has been evaluated through three cruises carried out in the Gironde estuary and plume, the Marennes-Oléron bay, and the Charente estuary, a river of minor importance that influences directly this bay. The field results from the Pertuis cruise (May 1991) and two others conducted in January and December of the same year show that the Gironde is an important source of dissolved cadmium for the bordering continental shelf (11 t year-1), while the Charente inputs are far lower (60 kg year-1). Dissolved Cd concentrations on the shelf vary according to the salinity, ranging from 0.76 nmol L-1 close to the Gironde to 0.15 nmol L-1 far from the shore. The field data as well as simulations from a 3D hydrodynamic model show that the Gironde plume reaches the Antioche Straits north of the Marennes-Oléron bay, and that the Charente plume is diluted in the bay by marine waters strongly influenced by the Gironde. This study confirms that the Gironde estuary is an important source of cadmium for the Marennes-Oléron bay. © 2000 Ifremer/CNRS/IRD/Éditions scientifiques et médicales Elsevier SAS.
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Net Fluxes of Dissolved Arsenic, Cadmium, Copper, Zinc, Nitrogen and Phosphorus from the Gironde Estuary (France): Seasonal Variations and Trends
Article
  • Oct 2000
The Gironde Estuary (south-western France), because of high contamination with metals and the proximity of large oyster-farming areas, has been a reference study site for 20 years. Research performed to date suggests a trend toward decontamination of the estuary, but a lack of information on seasonal variations has made difficult the evaluation of interannual changes. This study, which examines data obtained during five cruises over a 1-year period, takes into account various seasonal and hydrodynamic conditions. The fluctuations in dissolved net fluxes at the outlet of the upper estuary and the As, Cd, Cu, Zn, N and P concentrations are related to the season (January, February, May and October) or freshwater flow (400 to 1600 m3 s−1). Large seasonal variations are observed for As, Cu, N and P, and fluxes differ 3- to 4-fold according to the sampling month. Seasonal variations in net Cd and Zn fluxes are slight and relatively insignificant according to the confidence interval. For the other elements studied, the relationship with the river flow accounts for most of the seasonal variations. In the long-term, an increase in fluxes is found for nutrients, despite large seasonal differences. For Cd, the trend toward long-term decontamination is more clearly established, confirming the data of the French Mussel Watch, whereas the amplitude of seasonal variations masks any long-term trend for Cu. This study makes clear that when estuaries are subjected to marked fluctuations in freshwater flows and climatic conditions, an analysis of the concentrations or instantaneous fluxes of the various elements must be interpreted only as a part of the annual geochemical cycle.
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Pollution en Cadmium Dans Les Sediments du Lot (France) et Calcul du Stock de Polluant Cadmium Pollution in Sediments of the Lot River (France). Estimate of the Mass of Cadmium
Article
  • Dec 1995
After an industrial contamination of cadmium in the Lot river (France), an estimate of the cadmium stock stored in the bottom sediments of the river has been established in 1991. The behaviour and the evolution of this metallic concentration has been followed during the 1987–1994 period. It has been shown that there is a decrease of cadmium, in suspended matter and sediment, in relation to the decrease of fluxes flowing out the factory.
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The Conservative Behaviour of Trace Metals (Cd, Cu, Ni and Pb) and As in the Surface Plume of Stratified Estuaries: Example of the Rh ??ne River (France)
Article
  • Mar 1996
Concentrations of dissolved trace elements (Cd, Cu, Ni, Pb and As) were determined over a 4-year period (1987 –91) during contrasting hydrological conditions in a typically stratified system: the Rh ône river estuary. Dissolved concentrations in the river water vary by nearly one order of magnitude. Estimated average values (nM) are: As, 26; Cd, 0 ·27; Cu, 35; Ni, 27; and Pb, 0 ·42. They indicate some degree of contamination for Cd, Ni and Pb, as compared to levels in pristine rivers and world averages. Dissolved concentration variations were interpreted in terms of a dilution of two sources of trace metals, i.e. anthropogenic discharges and leaching of surface soils. Concentrations in the river suspended matter (Cd, Cu, Ni and Pb) were measured during one survey (July 1987); comparison with published data also seems to indicate variable inputs to the estuarine zone.The distributions of As, Cu, Ni and Pb are conservative in the Rh ône mixing zone, whereas a small excess is sometimes observed for dissolved Cd. On the whole, trace metal concentrations in the suspended matter tend to decrease from the mixing zone to the open sea. They are only weakly controlled by the amount of terrigenous alumino-silicates.A sorption experiment shows that Cd fixation on the suspended matter is enhanced by increased amounts of particulate organic matter. The simultaneous use ofin situandin vitrodistribution coefficients allows an estimation of the partitioning of particulate Cd between the reactive and non-reactive fractions of the suspended matter. This approach would confirm the mobilization of labile Cd in the saline surface plume.
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Cadmium in the gironde fluvioestuarine system: Behaviour and flow
Article
  • Nov 1990
  • SCI TOTAL ENVIRON
Major cadmium contamination of molluscs was discovered in the Gironde estuary. Studies were then undertaken on biota and on particulate and dissolved phases. Biota was studied by monitoring populations of oysters and mussels transplanted from uncontaminated areas into the Gironde. Studies on particulate and dissolved phases were carried out within the estuary, on the inner shelf, in Marennes-Oléron Bay, and in the drainage basin of the Gironde.It appears that: (i) the estuarine particulate stock, with its long residence time, plays a part in particulate-dissolved transformation, and thus has an effect on chemical conditions in the lower estuary and the coastal zone; (ii) the dissolved cadmium concentrations downstream can explain the concentrations measured in the oysters; (iii) the contamination is recent, and originates from the drainage basin; (iv) a geochemical cadmium budget in the Gironde has been formulated and is discussed.
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