Éditeur(s) : HAL CCSD Elsevier
Résumé : Siberian cratonic mantle
International audience
The processes that control water distribution in nominally anhydrous minerals from peridotites are twofold. Melt depletion will remove water while metasomatism can potentially add water to these minerals. These processes can lead to a wide range of outcomes in water contents, which in turn could play a role in mantle rheology and long-term cratonic root stability. To examine these complexities, water concentrations in minerals from well-characterized peridotites from the Udachnaya kimberlite in the central Siberian craton were analyzed by FTIR. The peridotites span a complete top to bottom cross-section of typical cratonic lithospheric mantle (2-7 GPa and 700-1400 °C). Diffusion modeling of water content profiles across olivine grains shows that water loss during decompression is limited to the 100 μm rims of olivines; the cores preserved their mantle water contents. Water contents range from 6 to 323 ppm wt H2O in olivine, 28-301 ppm H2O in orthopyroxene (opx), 100-272 ppm H2O in clinopyroxene (cpx) and 0-23 ppm H2O in garnet. Melting modeling cannot reproduce the high water contents of cratonic mantle peridotites and any potential partial melting trend must have been erased by later events. The water contents of minerals, however, are correlated with modal abundances of clinopyroxene and garnet, bulk rock FeO, TiO2 and SiO2 as well as with light and middle rare earth elements in clinopyroxene and garnet. These relationships are best interpreted as interaction of residual, melt-depleted peridotites with silicate melt, which produced modal and cryptic metasomatism. Importantly, the water enrichment in the Siberian cratonic mantle took place prior to kimberlite magmatism and eruption. Water addition by metasomatism occurred from pressures >4 GPa all the way to the base of the cratonic root below central Siberia, but was limited to shallower levels (<5 GPa) in the Kaapvaal cratonic lithosphere. The difference in olivine water contents at the deepest levels of the Kaapvaal (<5 ppm H2O) and Siberian (6-323 ppm H2O) cratonic roots may be linked to oxygen fugacity and resulting fluid speciation or, alternatively, to reaction with different metasomatic agents. Calculated viscosities for the deepest Udachnaya samples are similar to those inferred for the asthenosphere. If these xenoliths are representative of the deep cratonic lithosphere, water is not as important a parameter as previously thought in the strength of cratonic lithosphere, otherwise the cratonic root beneath Udachnaya would have been delaminated. Alternatively, the metasomatic xenoliths may not be representative of the Siberian cratonic root and kimberlites preferentially sample cratonic mantle lithosphere material located near, and metasomatized by, melt conduits, which served as channels for upward migration of water-rich melts and fluids including kimberlites. In that case, the cratonic root overall still may have relatively low water contents, which in addition to its less metasomatized (more refractory) and thereby buoyant nature, still play a role in making it strong enough to resist delamination by the surrounding asthenosphere.
ISSN: 0016-7037

hal-01053920
https://hal.archives-ouvertes.fr/hal-01053920
DOI : 10.1016/j.gca.2014.04.011

Éditeur(s) : University of the Virgin Islands University of the Virgin Islands ( Gallows Bay, St. Croix V.I )
Résumé : Cover title.
"September 1996."
"UVI Cooperative Extension Service, VI Resource Conservation and Development Council, Inc., USDA Natural Resources Conservation Service"--P. 1 of each section.
(Statement of Responsibility) Virgin Islands Resource Conservation & Development Council, Inc.
United States Virgin Islands
Virgin Islands of the United States
Virgin Islands of the United States
Virgin Islands of the United States
Virgin Islands of the United States

49936692

Éditeur(s) : Harper & brothers Harper & brothers ( New York )
Résumé : Page from Harper's Weekly Supplement, October 26, 1878.
The second largest hot water spring in the world.
Boiling Lake (Dominica)

Droits : All rights reserved by the source institution.
2004-292-1

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We performed torsional deformation experiments on pre-hydrated fine-grained olivine aggregates using an innovative experimental assembly to investigate water weakening in mantle rocks at high shear strains. San Carlos olivine powder was cold-pressed and then hot-pressed under hydrous conditions, producing aggregates with average grain sizes of 7 or 15 μm. Deformation experiments were performed in a high-resolution gas-medium apparatus equipped with a torsional actuator, under a confining pressure of 300 MPa, a temperature of 1200 °C, and constant shear strain rates ranging from 8 × 10−5 to 1.4 × 10−4 s−1. Maximum shear stresses range from 150 to 195 MPa. These values are 30% lower relative to those determined in previous torsion experiments on dry, fined-grained dunites under similar conditions. Textures and microstructures of the starting and deformed specimens were characterized by scanning and transmission electron microscopy. All deformed aggregates exhibit a shape-preferred orientation marking a foliation and lineation, as well as a reduction in mean grain size from 15 μm down to 3-4 μm due to dynamic recrystallization. Olivine crystallographic fabrics developed rapidly (γ < 0.1), but their strength, characterized by the J-index, is low compared to naturally deformed peridotites or to polycrystalline olivine deformed at similar finite shear strains under dry conditions. The crystallographic fabrics are consistent with deformation by a dislocation accommodated creep mechanism with activation of multiple {0 k l}[1 0 0] systems, among which the (0 1 0)[1 0 0] slip system is dominant, and minor participation of the (0 1 0)[0 0 1] slip system. Transmission electron microscopy confirmed the occurrence of dislocations with [1 0 0] and [0 0 1] Burgers vectors in most grains. Analysis of unpolarized infrared spectra indicates that hydrogen concentration in the olivine lattice is below the saturation level of 18 ppm wt H2O, which is similar to those typically observed in spinel-bearing peridotite xenoliths, and also provide evidence for water-rich inter-granular material trapped in pores and grain boundaries. Seismic properties computed from the CPO observations correspond to those most commonly observed in naturally deformed mantle peridotites with fast P-wave propagation and S-wave polarization subparallel to the shear direction. These torsion experiments on fine-grained olivine polycrystals under hydrous conditions indicate that water weakening under lithospheric conditions is linked to various defects with hydrogen in the olivine structure, as well as with water-derived species in grain boundaries or pores.
ISSN: 0031-9201

hal-00745170
https://hal.archives-ouvertes.fr/hal-00745170
DOI : 10.1016/j.pepi.2012.05.001

Éditeur(s) : Nature
Résumé : Mud volcanism is an important natural source of the greenhouse gas methane to the hydrosphere and atmosphere(1,2). Recent investigations show that the number of active submarine mud volcanoes might be much higher than anticipated ( for example, see refs 3 - 5), and that gas emitted from deep-sea seeps might reach the upper mixed ocean(6-8). Unfortunately, global methane emission from active submarine mud volcanoes cannot be quantified because their number and gas release are unknown(9). It is also unclear how efficiently methane-oxidizing microorganisms remove methane. Here we investigate the methane-emitting Haakon Mosby Mud Volcano (HMMV, Barents Sea, 72 degrees N, 14 degrees 44' E; 1,250 m water depth) to provide quantitative estimates of the in situ composition, distribution and activity of methanotrophs in relation to gas emission. The HMMV hosts three key communities: aerobic methanotrophic bacteria (Methylococcales), anaerobic methanotrophic archaea (ANME-2) thriving below siboglinid tubeworms, and a previously undescribed clade of archaea (ANME-3) associated with bacterial mats. We found that the upward flow of sulphate- and oxygen-free mud volcano fluids restricts the availability of these electron acceptors for methane oxidation, and hence the habitat range of methanotrophs. This mechanism limits the capacity of the microbial methane filter at active marine mud volcanoes to <40% of the total flux.
Nature (depuis 1997) (0028-0836) (Nature), 2006-10 , Vol. 443 , N. 7113 , P. 854-858

Droits : 2006 Nature Publishing Group
http://archimer.ifremer.fr/doc/2006/publication-4514.pdf
DOI:10.1038/nature05227
http://archimer.ifremer.fr/doc/00000/4514/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In order to perform a human and ecological risk assessment of pharmaceutical products (PPs) in natural waters, it is necessary to accurately quantify a broad variety of PPs at low concentrations. Although numerous currently implemented analytical methodologies, less is known about the preservation of PPs in natural water samples within the period before analysis (holding time, storage conditions). This paper is the first literature review about the stability of PPs in natural waters (surface and groundwaters) during sample storage. The current work focuses on a comparison of the performances of the available preservation techniques (filtration, container materials, storage temperature, preservative agents, etc.) for PPs in samples. All 58 reviewed PPs may be successfully stabilized during 7 days in surface waters by at least one appropriate methodology regarding temperature, acidic and non-acidic preservatives. When temperature is not a sufficient preservation parameter f! or some PPs (hormones and fluoxetine) its combination with the addition of chemical agents into the samples may prolong the integrity of the PPs during storage in surface water. There is a strong need to use standard protocols to assess and compare the stability of PPs in environmental water matrices during storage as well as during analytical preparation or analysis (European criteria 2002/657/EC). Since the stability of PPs during sample storage is a critical parameter that could call into question the quality of the data provided for the concentrations, the design of stability studies should rigorously take into account all critical parameters that could impact the concentrations of the PPs with time.
Talanta

insu-00839186
https://hal-insu.archives-ouvertes.fr/insu-00839186
DOI : 10.1016/j.talanta.2013.01.042

Résumé : The boundaries of territorial waters are not as stable as boundaries on land. Nowadays, indeed they are characterised by their very mobility. No doubt the reason for this is political. A state which sought to further her own interests by enlarging her domain within her own waters would encounter no sovereign opposition. Additonally, with the collapse of the traditional "understanding" regarding the conception of -and the criteria governing -maritime boundaries. nations chose the most effective methods of appeasing their own needs and appetites. This was achieved with the maximum ingenuity. The natural boundary myth was shaken sometimes before and sometimes simultaneously with, the cultivation of negotiating skills or, from a position of strength. the imposition of "political limits". Fruitful sources of approximation were provided by phenomena such as low-water mark, the continental shelf. the Humboldt current and so on. As for accuracy. however. this was obtained by the application of geometrical methods such as calculation on a straight line basis or by equidistance or. again. by numeric evaluation : expression of distance in nautical miles. The general effect of this medley of arguments - or pretexts - has been to add to the fluctuating nature of sea boundaries rather than contribute to their stability. In fact. the only way stabilisation of these boundaries is usually achieved is by confrontation between two or more adjacent and competing sovereign states once the question of demarcation has been hammered out. The ocean, "man's common heritage", seems to have entered a phase of parcelling out, of sharing. [NOT CONTROLLED OCR]
Les frontières maritimes n'ont pas la stabilité des frontières terrestres. Dans la présente époque, au contraire, elles se caractérisent essentiellement par leur mobilité. La principale raison de ce phénomène est sans doute d'ordre politique : au large de sa mer territoriale, l'État ne rencontre pas d'autre souveraineté lorsque ses intérêts le portent à étendre son emprise. Aussi, lorsque le « consensus » international traditionnel sur la conception et le critère de la frontière maritime fut ruiné. les États laissèrent libre cours à leur ingéniosité pour choisir les techniques les plus adéquates à la pleine satisfaction de leurs besoins et de leurs appétits. Tour à tour, et, parfois. simultanément. fut agité le mythe de la « frontière naturelle » et cultivé l'art de négocier ou d'imposer, selon les rapports de force. des "limites politiques". La "laisse de basse mer", la "marge continentale ", le courant de Humboldt. etc. fournirent des approximations fécondes. Mais la certitude est venue des techniques géométriques (lignes de base droites, équidistance) ou des évaluations chiffrées (distance exprimée en milles marins). De façon générale. ces divers arguments, ou prétextes. ont puissamment alimenté le dynamisme des frontières maritimes et fort peu contribué à leur stabilisation. Celle-ci ne procède finalement que de la rencontre de deux ou plusieurs souverainetés voisines et concurrentes. une fois tranchées les querelles de "bornage". L'océan, "héritage commun de l'humanité", est entré, semble-t-il, dans une phase de liquidation et de partage... [OCR NON CONTRÔLE]

Droits : 1979 CNEXO
http://archimer.ifremer.fr/doc/1979/rapport-4798.PDF
http://archimer.ifremer.fr/doc/00000/4798/

Éditeur(s) : Gauthier-Villars
Résumé : The variability of ''yellow substance'' in waters of the Skagerrak and the Kattegat was studied during the international Skagex programme in 1990 and 1991. Data on attenuation of light and fluorescence of dissolved organic matter (DOM) in sea water were collected with a spectral transmissiometer and a submersible fluorometer within a depth range of 0-250 m at several stations. More than fifty-fold variations of fluorescence intensity over space and time were due to the combined action of different sources of DOM in the straits. The surface maximum of fluorescing DOM, related to river outflow, was spreading from Oslo fjord to the central Skagerrak in late spring. This maximum may be ecologically important because it diminishes shortwave PAR. In the autumn the brightest DOM fluorescence was found in the Kattegat and along the Norwegian coast in accordance with earlier studies. The local minima of DOM fluorescence are associated with the Jutland current. Both the instability of the current and a ten-fold difference in DOM content between deep layers of the Skagerrak and Kattegat resulted in strong synoptic variability of fluorescence in the transitional area between the straits. Seasonal and synoptic variabilities of ''yellow substance'' were minimal in the southern Kattegat. The vertical gradients of DOM fluorescence were mostly negative at the depth of the thermocline of the open Skagerrak in spring, reaching values of 40-50 % m-1. Fine structure and complex shape were inherent to fluorescence profiles from areas of intensive water mixing. DOM fluorescence closely covaried with attenuation of UV light: the correlation coefficient was + 0.9 for wavelength w <= 350 nm regardless of season. The inverse dependence between wavelength derivative and magnitude of UV attenuation in the straits did not change with season. DOM fluorescence and water salinity were negatively correlated at depths of 25-50 m but they varied independently in the upper 10 m. No significant correlation between fluorescence and nitrates has been found. Estimates of correlation with phosphates ranged from 0.7 to 0.8. In general, the changes of fluorescence were due to variations of DOM content in sea water but not to variability of DOM composition or state. The properties of DOM fluorescence in the Skagerrak-Kattegat area make it a useful natural tracer of water movements suitable for active remote sensing with airborne lidar.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1993 , Vol. 16 , N. 2 , P. 115-125

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00099/21041/18667.pdf
http://archimer.ifremer.fr/doc/00099/21041/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The equilibrium phase relations of a mafic durbachite (53 wt.% SiO2) from the TA (TM) ebi pluton, representative of the Variscan ultrapotassic magmatism of the Bohemian Massif (338-335 Ma), have been determined as a function of temperature (900-1,100A degrees C), pressure (100-200 MPa), and H2O activity (1.1-6.1 wt.% H2O in the melt). Two oxygen fugacity ranges were investigated: close to the Ni-NiO (NNO) buffer and 2.6 log unit above NNO buffer (a dagger NNO + 2.6). At 1,100A degrees C, olivine is the liquidus phase and co-crystallized with phlogopite and augite at 1,000A degrees C for the whole range of investigated pressure and water content in the melt. At 900A degrees C, the mineral assemblage consists of augite and phlogopite, whereas olivine is not stable. The stability field of both alkali feldspar and plagioclase is restricted to low pressure (100 MPa) at nearly water-saturated conditions (< 3-4 wt.% H2O) and T < 900A degrees C. A comparison between experimental products and natural minerals indicates that mafic durbachites have a near-liquidus assemblage of olivine, augite, Ti-rich phlogopite, apatite and zircon, followed by alkali feldspar and plagioclase, similar to the mineral assemblage of minette magma. Natural amphibole, diopside and orthopyroxene were not reproduced experimentally and probably result from sub-solidus reactions, whereas biotite re-equilibrated at low temperature. The crystallization sequence olivine followed by phlogopite and augite reproduces the sequence inferred in many mica-lamprophyre rocks. The similar fractionation trends observed for durbachites and minettes indicate that mafic durbachites are probably the plutonic equivalents of minettes and that K- and Mg-rich magmas in the Bohemian Massif may have been generated from partial melting of a phlogopite-clinopyroxene-bearing metasomatized peridotite. Experimental melt compositions also suggest that felsic durbachites can be generated by simple fractionation of a more mafic parent and mixing with mantle-derived components at mid crustal pressures.
ISSN: 0010-7999

hal-00618418
https://hal.archives-ouvertes.fr/hal-00618418
DOI : 10.1007/s00410-009-0430-5

Éditeur(s) : Elsevier Science Bv
Résumé : A Lagrangian approach based on a physical-biogeochemical modeling was used to compare the potential transfer of cadmium (Cd) from natural and anthropogenic sources to plankton communities (Cd-uptake) in the NorthWest African upwelling. In this region, coastal upwelling was estimated to be the main natural source of Cd while the most significant anthropogenic source for marine ecosystem is provided by phosphate industry. In our model experiment, Cd-uptake (natural or anthropogenic) in the North-West African upwelling is the result of an interplay between the Cd dispersion (by advection processes) and the simulated biological productivity. In the Moroccan waters, advection processes limit the residence time of water masses resulting in a low natural Cd-uptake by plankton communities while anthropogenic Cd-uptake is high. As expected, the situation is reversed in the Senegalo-Mauritanian upwelling where natural Cd-uptake is higher than anthropogenic Cd-uptake. Based upon an estimate of Cd sources, our modeling study shows, unexpectedly, that the anthropogenic signal of potential Cd-bioaccumulation in the Moroccan upwelling is of the same order of magnitude as the natural signal mainly present in the Senegalo-Mauritanian upwelling region. A comparison with observed Cd levels in mollusk and fishes, which shows overall agreement with our simulations, is confirming our estimates.
Science Of The Total Environment (0048-9697) (Elsevier Science Bv), 2015-02 , Vol. 505 , P. 870-888

Droits : 2014 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00252/36310/35200.pdf
DOI:10.1016/j.scitotenv.2014.10.045
http://archimer.ifremer.fr/doc/00252/36310/

Éditeur(s) : HAL CCSD
Résumé : Background. Chlorine is the most widely used disinfectant for drinking water treatment. During treatment process, the natural organic matter present in water reacts with chlorine to form disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), the most occurring ones. Several identified DBPs were recognized carcinogens or fetotoxic in animals. We conducted two epidemiological studies to assess the health effects of human exposure to DBPs regarding cancer and reproduction. Association between THM exposure and the risk of bladder cancer: a pooled analysis of 3 European case-control studies. The study included 2381 cases and 3086 controls from 3 case-control studies (France, Finland, Spain). Environmental exposure to SPCs was measured by THM concentrations in water distribution systems, retrospectively estimated through the 40-year exposure window. Information about water uses (tap water ingestion, showers and baths, swimming-pool attendance) was available. An increased risk of bladder cancer was observed, in men only, with increasing THM concentrations in water systems and duration of exposure to chlorinated surface water. No association was observed with exposure through tap water ingestion. Exposure through showers, baths and swimming in pools (available in Spanish study only) was associated with an increased risk of bladder cancer. Three North-American case-control studies were joined to the three European ones into a meta-regression. No specific dose-response relationship was identified for European studies. A global dose-response relationship was consequently estimated, including 4351 cases and 7055 controls. Association between DBP exposure and the risk of preterm birth and Intra-Uterine Growth Retardation (IUGR). This study was conducted within the PELAGIE cohort (3400 pregnant women included in early pregnancy, in Brittany, France, between 2002 and 2006). Exposure during pregnancy was measured by 2 indicators: THM concentrations in water distribution systems and a biomarker of HAA ingestion, the level of trichloroacetic acid in maternal urine at inclusion (in a nested case-control study). The regulatory database SISE-Eaux was used to estimate THMs concentrations in the water distribution systems. Water uses during pregnancy (ingested tap water, swimming-pool attendance, showers and bath frequencies and duration) were collected with questionnaires. Our results suggest an association between prenatal exposure to DBPs (THMs and HAAs) and the risk of IUGR. No association was found with the risk of preterm birth.
Contexte. La chloration est le traitement le plus utilisé pour désinfecter l’eau distribuée à la population. Lors du traitement, des sous-produits de chloration (SPCs) se forment par réaction de la matière organique naturelle présente dans l’eau avec le chlore. Les produits les plus présents sont les trihalométhanes (THMs), les acides haloacétiques (HAAs). Des études toxicologiques (animales et in vitro) ont montré la génotoxicité et/ou carcinogénicité et la reprotoxicité de certains SPCs. Nous avons mené deux études évaluant les effets sur la santé humaine de l’exposition aux SPCs, dans le domaine du cancer et de la reproduction. Association entre exposition aux THMs et risque de cancer de la vessie : une analyse poolée de 3 études cas-témoins européennes. Cette analyse a inclus 2381 cas et 3086 témoins issus de 3 études cas-témoins (France, Espagne, Finlande). L’exposition environnementale aux SPCs a été mesurée par la concentration en THMs estimée rétrospectivement dans les réseaux de distribution d’eau au cours des 40 années de la fenêtre d’exposition. Les usages de l’eau connus sont l’ingestion, les douches et les bains, la fréquentation de piscine (étude espagnole seulement). Une relation croissante a été observée entre le niveau environnemental de THMs, la durée d’exposition à une eau de surface chlorée et le risque de cancer de la vessie, chez les hommes uniquement. Aucune association n’a été observée avec l’exposition via l’ingestion d’eau du robinet. L’exposition via les douches, les bains et la piscine est apparue liée au risque de cancer de la vessie. Trois études cas-témoins nord-américaines ont été intégrées dans une méta-régression. Aucune spécificité européenne de la relation dose-réponse n’a été mise en évidence. Une relation dose-réponse globale incluant 4351 cas et 7055 témoins a été estimée. Association entre exposition aux SPCs et risque de prématurité et de retard de croissance intra-utérin (RCIU). Cette étude est issue de la cohorte bretonne Pélagie (3400 femmes enceintes recrutées en début de grossesse entre 2002 et 2006). L’exposition pendant la grossesse a été mesurée à l’aide de 2 indicateurs : la concentration en THMs de l’eau distribuée dans les réseaux et le dosage d’un biomarqueur urinaire (acide trichloroacétique) pour un sous-échantillon de femmes (étude cas-témoins nichée). Les niveaux dans les réseaux proviennent de la base de données réglementaire SISE-Eaux. Les usages de l’eau du robinet par les femmes pendant la grossesse ont été collectés par questionnaire (quantité d’eau du robinet bue, fréquentation de la piscine, fréquence et durée des douches et des bains). Notre étude suggère une association entre l’exposition prénatale aux SPCs et le risque de RCIU. Aucune association n’est observée avec le risque de prématurité.
https://tel.archives-ouvertes.fr/tel-00927735

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2013REN1B008
tel-00927735
https://tel.archives-ouvertes.fr/tel-00927735
https://tel.archives-ouvertes.fr/tel-00927735/document
https://tel.archives-ouvertes.fr/tel-00927735/file/COSTET_DEIBER_Nathalie4.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
11 4 : CEA/HC 12 13 Corresponding author: 14 pierre.legoff@cea.fr -+333 80 23 40 00 -+333 80 23 52 09 15 16 Abstract 17 As one of the three natural isotopes of hydrogen, tritium is ubiquitous and might potentially 18 be present in any water or organic molecule that constitutes a biological matrix. Milk is one of 19 the most frequently monitored foodstuffs in the vicinity of chronic release of radionuclides, as 20 it is a very common product and also because it integrates deposition on large areas of grass at 21 a local scale. Different parameters have been studied to assess their impact on the reliability 22 of tritium measurements. The volume of the sample, the technique used to extract the water 23 and the level of dehydration modulate the results but in different ways: dispersion of results, 24 under-or overestimation of the tritium activity. The influence of sample storage and 25 preparation has also been investigated. Methodological improvements of tritium 26 measurements in the free water of milk are proposed. 27 28
ISSN: 0265-931X

hal-01117741
https://hal.archives-ouvertes.fr/hal-01117741
https://hal.archives-ouvertes.fr/hal-01117741/document
https://hal.archives-ouvertes.fr/hal-01117741/file/Tritium%20in%20the%20free%20water%20of%20milk-FINAL.pdf
DOI : 10.1016/j.jenvrad.2013.09.006

Éditeur(s) : HAL CCSD Springer Verlag (Germany) Springer Verlag
Résumé : International audience
Replenished axial melt lenses at fast-spreading mid-oceanic ridges may move upward and intrude into the overlying hydrothermally altered sheeted dikes, resulting in high-grade contact metamorphism with the potential to trigger anatexis in the roof rocks. Assumed products of this process are anatectic melts of felsic composition and granoblastic, two-pyroxene hornfels, representing the residue after partial melting. Integrated Ocean Drilling Program Expeditions 309, 312, and 335 at Site 1256 (eastern equatorial Pacific) sampled such a fossilized oceanic magma chamber. In this study, we simulated magma chamber roof rock anatectic processes by performing partial melting experiments using six different protoliths from the Site 1256 sheeted dike complex, spanning a lithological range from poorly to strongly altered basalts to partially or fully recrystallized granoblastic hornfels. Results show that extensively altered starting material lacking primary magmatic minerals cannot reproduce the chemistry of natural felsic rocks recovered in ridge environments, especially elements sensitive to hydrothermal alteration (e.g., K, Cl). Natural geochemical trends are reproduced through partial melting of moderately altered basalts from the lower sheeted dikes. Two-pyroxene hornfels, the assumed residue, were reproduced only at low melting degrees (<20 vol%). The overall amphibole absence in the experiments confirms the natural observation that amphibole is not produced during peak metamorphism. Comparing experimental products with the natural equivalents reveals that water activity (aH2O) was significantly reduced during anatectic processes, mainly based on lower melt aluminum oxide and lower plagioclase anorthite content at lower aH2O. High silica melt at the expected temperature (1000–1050 °C; peak thermal overprint of two-pyroxene hornfels) could only be reproduced in the experimental series performed at aH2O = 0.1.
ISSN: 0010-7999

hal-01174139
https://hal.archives-ouvertes.fr/hal-01174139
DOI : 10.1007/s00410-015-1136-5

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The occurrence of cyanobacterial blooms is drastically increasing in temperate countries and drinking water resources are threatened. As a result, cyanotoxins should be considered in water treatment to protect human health. This study presents a state of the art on cyanotoxins in water and their behaviour towards chlorination, a common drinking water disinfection process. Chlorination efficiency on cyanotoxins alteration depends on pH, chlorine dose and oxidant nature. Microcystins and cylindrospermopsin are efficiently transformed by chlorine, with respectively 6 and 2 by-products identified. In addition, chlorination of microcystins and cylindrospermopsin is associated with a loss of acute toxicity. Even though they have been less investigated, saxitoxins and nodularins are also altered by chlorine. For these toxins, no by-products have been identified, but the chlorinated mixture does not show acute toxicity. On the contrary, the fact that anatoxin-a has a very slow reaction kinetics suggests that this toxin resists chlorination.
ISSN: 0041-0101

hal-01122372
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122372
DOI : 10.1016/j.toxicon.2009.10.028
PUBMED : 19874838

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
During the treatment process of drinking water, disinfectants (chlorine, ozone, chlorine dioxide) react on water containing organic matter and bromide to produce disinfection by-products at trace levels. Among them, five of the nine existing halo-acetic acids (HAAs) are commonly found in drinking water (monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), and Trichloroacetic acid (TCAA)), including four classified in the 2B IARC group of potential carcinogens (BCAA, DBAA, DCAA, TCAA). With respect to drinking water quality, guidelines are proposed by WHO (2006) and water quality standards are imposed in many countries such as less than 100 μg/L for the sum of the five HAAs by US EPA (1998) and Canadian Health Department (2008). For this purpose, two analytical methods are commonly used, GC/MS with derivatization and LC/MS, UV or conductivity. A new method, based on two-dimensional ion chromatography (IC 2D) with suppressed conductivity is proposed. This method presents the main advantage of offering a quick implementation compared to GC or LC methods: direct injection, slight maintenance, lower cost of investment, by leading to good performances (specificity and sensitivity). The use of two different selectivity columns, and the fractionation on the first dimension canceling interferences, improves the specificity. The sensitivity is enabled by interfacing a preconcentration column between the two different internal diameter columns. The analytical conditions are optimized for the analysis of nine HAAs. The performances of the method are evaluated. The optimized method applied to natural water samples demonstrates its ability to quantify HAAs at trace levels in drinking water.
Microchemical Journal

hal-00877151
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877151
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877151/document
DOI : 10.1016/j.microc.2013.07.012

Éditeur(s) : Université de Bretagne Occidentale
Résumé : This activity report entitled (“Chemical contamination of the marine environment: from measurement to risk assessment”) summarizes the main stages my career at Ifremer from November 1975 to june 2013. The first chapter deals with the seawater chlorination and chlorinated waters released into the sea, the identification and the conditions of the formation of various by-product of these processes. The second chapter concerns PCBs, their nature, their chemical analysis in environmental matrices. PCBs are considered as the best examples of persistant and bioaccumulable compounds and therefore, in all this report they are flagship contaminants to which other groups of studied substances are compared. The third chapter refers to studies performed within marine pollution monitoring programme RNO (Réseau National d’Observation de la qualité de l’environnement marin - National observation network on the quality of the marine environnment) and well as other more limited studies like a first assessement on the presence of dioxins and dioxin-like PCBs in the French coastal marine environment and last, on the use of zebra mussel (Dresseinia polymorpha) as sentinelle species of the chemical contamination in the Seine estuary. The next two chapters are about bioaccumulation and about the distribution of organic contaminants (PCBs, dioxins, PAHs, PBDEs) in marine organisms and in marine foodwebs. These studies aim at a better knowledge of the presence and fate of these compounds in fish and marine organisms eitheir in an environmental perspective (chapter IV) or in order to contribute to the assessment of their health impact, or more precisely to estimate therelative part of fish and seafood to the human exposure to chemical residues (chapter V). To conclude, the chapter VI concerns the PCB and dioxin fingerprints in the various studied marine matrices ; analytical and environmental interpretations of the observed differences are suggested as well as possible applications.
Ce bilan d’activité intitulé « Contamination chimique du milieu marin : de la mesure à l’évaluation des risques » retrace les étapes essentielles de mon parcours à Ifremer entre novembre 1975 et juin 2013. Le premier chapitre traite de la chloration dans l’eau de mer et les rejets chlorés en mer, l’identification des sous-produits formés lors de ces traitements, les conditions de leur formation. Le second chapitre concerne la nature des PCB et leur analyse dans les matrices environnementales. Les PCB considérés comme les meilleurs exemples de composés persistants bioaccumulables constituent les « contaminants phares » de l’ensemble de ce travail et c’est par rapport aux PCB que sont comparés et évalués les autres groupes de contaminants étudiés. Le troisième chapitre se rapporte aux travaux réalisés dans le cadre de la surveillance RNO (Réseau National d’Observation de la qualité de l’environnement marin) ainsi que dans des études ponctuelles comme un premier inventaire sur les niveaux de présence des dioxines (PCDD et PCDF) dans l’environnement marin littoral ou sur l’utilisation de la moule zébrée (Dresseinia polymorpha) comme espèce indicatrice de la contamination de l’estuaire de la Seine. Les deux chapitres suivants sont consacrés aux travaux sur la bioaccumulation et aux contaminants organiques (PCB, dioxines, HAP, PBDE) dans les organismes et les réseaux trophiques marins soit dans une perspective environnementale sur le devenir des contaminants dans le vivant (chapitre IV) soit dans le cadre de l’évaluation des risques sanitaires ou, plus précisément, de l’estimation de la contribution de la consommation des produits de la mer à l’exposition de l’homme aux résidus chimiques (chapitre V). Pour terminer, le chapitre VI concerne les empreintes de PCB et de dioxines dans les différentes matrices étudiées ; une interprétation analytique et environnementale des différences observées est proposée ainsi que de possibles applications.

Droits : 2013 UBO
http://archimer.ifremer.fr/doc/00168/27946/26237.pdf
http://archimer.ifremer.fr/doc/00168/27946/

Éditeur(s) : ISTPM
Résumé : Table of Contents The Natural Environment Production centres Oyster farming centres Mussel farming centres Chapter I. - The Physicochemical Environment I. Sea Water a) Transparency, turbidity b) Temperature c) Salinity d) Dissolved gases e) Substances dissolved in the water f) Water movements g) Hydrology of the main shellfish farming centres II. Soils a) Soil properties b) Mechanical amendment of soils, its effects c) Fertilisation of soils in shellfish farming d) Changes in soils due to farming Bibliography Chapter II. - The Natural Environment Phytoplankton Zooplankton Basic biology of phytoplankton Assessment of phytoplankton production, notion of primary productivity Phytoplankton from a few shellfish farming regions Microphytobenthos Factors controlling primary productivity Toxicity of planktonic organisms; red tides Bibliography Chapter III – Alterations in the Natural Environment Pollution I. Chemical Pollution Definitions Influence of turbidity A. Telluric pollution 1o Domestic pollution 2o Agriculture-related pollution 3o Industrial pollution B. Pelagic pollution 1o Pollution through hydrocarbons Conclusion II. Bacterial Pollution Future of micro-organisms in the sea A. Specimen conditions B. Phenomena of dispersion Survival of germs in the marine environment A. Factors influencing the total microbial content B. Resistance of various groups of germs Consequences of bacterial pollutions on shellfish and shellfish farming Shellfish Shellfish farming Conclusion Bibliography
Sommaire : Le milieu naturel Les centres de production Les centres ostréicoles Les centres mytilicoles Chapitre I. - le milieu physico-chimique I. L'eau de mer a) Transparence, turbidité b) Température c) Salinité d ) Les gaz dissous e) Les substances dissoutes dans l'eau f) Les mouvements de l'eau g) Hydrologie des principaux centres conchylicoles IL Les sols a ) Propriétés des sols b) Amendement mécanique des sols, ses effets c) La fertilisation des sols en conchylicutture d) Evolution des sols du fait de la culture Bibliographie Chapitre II. - le milieu biologique Le phytoplancton Le zooplancton Biologie sommaire du phytoplancton Evaluation de la production de phytoplancton, notion de productivité primaire Phytoplancton de quelques régions conchylicoles Le microphytobenthos Facteurs contrôlant la productivité primaire Toxicité d'organismes planctoniques ; les eaux rouges bibliographie Chapitre III - les altérations du milieu naturel. Les pollutions I. Les pollutions chimiques Définitions Influence de la turbidité A. Pollution tellurique 1° Pollution d'origine domestique 2° Pollutions liées aux activités agricoles 3° Pollutions industrielles B. Pollution pélagique 1° Pollution par les hydrocarbures Conclusion II. Les pollutions bactériennes Devenir des microorganismes dans la mer A. Conditions de prélèvements B. Phénomènes de dispersion Survie des germes dans le milieu marin A. Facteurs influant sur la teneur microbienne globale B. Résistance des divers groupes de germes Conséquences des pollutions bactériennes sur les coquillages et sur la conchyliculture Les coquillages La conchyliculture Conclusion Bibliographie
Revue des Travaux de l'Institut des Pêches Maritimes (0035-2276) (ISTPM), 1974-09 , Vol. 38 , N. 3 , P. 217-337

Droits : Ifremer
http://archimer.ifremer.fr/doc/1974/publication-1776.pdf
http://archimer.ifremer.fr/doc/00000/1776/

Éditeur(s) : Elsevier
Résumé : Dissolved and particulate Hg fluxes in the Lot-Garonne-Gironde fluvial-estuarine system were obtained from observation of daily discharge and suspended particulate matter (SPM) concentrations. In addition to the measurements of the total dissolved (< 0.45 gm) and particulate Hg (> 0.45 gm), called HgTD and HgTp respectively, the dissolved inorganic Hg species (HgRD) were determined monthly. Geochemical background values for HgTp in sediments and SPM were similar to crustal values and to typical concentrations in SPM of non-contaminated river systems, respectively. The Riou Mort watershed already known as the origin of important historical polymetallic (e.g., Cd, Zn) pollution was identified as an important Hg point source. In the downstream Lot River, Hg concentrations were clearly higher than those in other moderately contaminated systems. The mean relative contribution of HgRD to HgTD in the Lot River and in the Garonne River was close to 25% and 50%, respectively, and showed no correlation with water discharge or SPM concentration. Depending on the origin and nature of SPM, HgTp concentrations were correlated or not with particulate organic C (POC). Maximum HgTp concentrations were measured in samples containing low POC concentrations and were attributed to sediment resuspension. In contrast, high POC concentrations (6-17%) during algal blooms were associated with low/moderate HgTp concentrations (< 0.5 mg kg(-1)) at different sites, suggesting that Hg concentrations in fluvial phytoplankton may be limited by bioavailability of dissolved Hg and/or physiologically controlled Hg accumulation. Mercury was mostly (up to 98%) transported in the particulate phase with estimated annual Hg fluxes at the outlet of the Lot River system ranging from 35 to 530 kg a(-1) for the past decade. The minimum anthropogenic component (58-84% of total Hg fluxes) could not be explained by present Riou Mort point source contributions, suggesting important Hg release from contaminated sediment as a major source and from downstream point sources (e.g., coal-fired power plants and/or metal processing industries). HgTp concentrations and fluxes were strongly related to hydrologic variations and were clearly increased by riverbed dredging during lock construction. Therefore, the estimated Hg stocks in the Lot River sediment (5-13 tons) represent an important potential Hg source for the downstream fluvial-estuarine system.
Applied Geochemistry (0883-2927) (Elsevier), 2006-03 , Vol. 21 , N. 3 , P. 515-527

Droits : 2006 Elsevier Ltd All rights reserved
http://archimer.ifremer.fr/doc/2006/publication-1343.pdf
DOI:10.1016/j.apgeochem.2005.12.004
http://archimer.ifremer.fr/doc/00000/1343/

Résumé : This study contributes to inventory programme on emerging pollutants in French waters and to the general reflection which will enable to update the list of relevant substnaces to be included in the new monitoring programmes to come. This work concerns the coastal part of the inventory programme on marine waters and sediments of France and five overseas french departments (OFD). In this goal, passive sampling techniques and direct extraction techniques have been tested through the implementation of in situ systems integrators POCIS (Polar Organic Chemical Integrative Sampler) and the extraction by SBSE bars (Stir bar sorptive extraction) directly in the waters sampled. Finally, analyzes of sediment completed the acquisition of data. Arount 40 stations were sampled for shore waters and sediments were collected from 7 stations in France and 5 stations in the OFD (one station/OFD). In analytical terms, 1054 analyzes were carried out on POCIS membranes and only 64 data exceeded the limit of detection (LD), 12726 analyzes came from SBSE extractions and 304 were above the LD and 1536 analyzes in sediment showed that 237 data were above the limit of quantification (LQ). Finally, 169 different substances were investigated and 68 of them were detected at least once in water or sediment. The lack of replicates for POCIS analyzes and those in the sediment limited the statistical treatment of data. The results were used to determine the level of contamination, the detection frequency (FD), the distribution of substances between France and OFD, the comparison with environmental thresholds (the PNEC) and the origin/use of the substances. In littoral waters, 32 substances were identified and 19 were quantified. In the sediment, 47 substances were quantified. Nine substances were detected in both water and sediment. In France, the 15 substances that were quantified at higher frequencies (> 50 %, one out of 2 sites) were quantified in sediments. These are the congeners of PAHs (11 substances), organic forms of tin (2 substances), diethyl lead and 209 PBDE congener. In the OFD, the 22 substances that were quantified at higher frequencies (> 50 %, one out of 2 sites) were measured in sediments. These are congeners of PAHs (13 substances) , alkylphenols ( 3 molecules: the mono and diethoxyate nonylphenol and the 4-ter butylphenol ), the organic forms of tin (2 substances), products of metabolism insecticide DDT ( 2 products), diethyl lead and the 209 PBDE congener. The study of the highest concentrations distribution of substances between France and OFD shows that the 5 (among 19 molecules) highest concentrations in water and the 6 (among 47 molecules) highest concentrations in sediments are found in OFD. Reference to PNEC indicates that four pesticides in water and 11 different substances in sediments exceed the environmental thresholds. Substances with highest detection frequency are found in the sediment. The distribution of data by use or nature of the substance shows that plasticizers and pesticides predominate in raw water, both in France and overseas departments while PAHs in sediments dominate in France and in OFD.
Cette étude contribue au programme d’inventaire des substances chimiques émergentes dans les eaux françaises et à la réflexion qui doit permettre d’actualiser la liste des substances pertinentes à surveiller de manière régulière dans le cadre des nouveaux programmes de surveillance. Ce travail concerne la partie littorale de l’inventaire, sur les eaux brutes et les sédiments de la métropole et des 5 DOM. Dans ce cadre, des techniques d’échantillonnage passif (EP) et d’extraction directe ont été testées grâce à la mise en place in situ de systèmes intégrateurs POCIS (Polar Organic Chemical Integrative Sampler) et à l’extraction par des barres SBSE (Stir Bar Sorptive Extraction) directement dans les eaux échantillonnées. Enfin des analyses de sédiments ont complété l’acquisition des données. L’eau d’une quarantaine de stations a été échantillonnée et des sédiments ont été prélevés sur 7 stations en métropole et dans 5 stations dans les DOM (une station par DOM). En termes analytiques, 1054 analyses ont été réalisées sur les membranes POCIS et 64 dépassaient la limite de détection (LD), 12726 analyses ont concerné les extractions par SBSE pour 304 résultats situés au dessus de la LD et 1536 analyses effectuées dans le sédiment ont donné 237 valeurs supérieures à la limite de quantification (LQ). Au bilan 169 substances différentes ont été recherchées et 68 d’entre elles ont été détectées au moins une fois dans l’eau brute ou le sédiment. L’absence de réplicats pour les analyses POCIS et celles dans le sédiment a limité le traitement statistique des données. Les résultats ont permis de déterminer le niveau de contamination, la fréquence de détection (FD), la distribution métropole/DOM des substances, la comparaison avec les seuils environnementaux (PNEC) et l’origine des substances. Dans l’eau 32 substances ont été identifiées et 19 ont été quantifiées. Dans le sédiment 47 substances sont quantifiées .Neuf substances sont détectées à la fois dans l’eau et le sédiment. En métropole, les 15 substances quantifiées aux plus hautes fréquences (> 50%, soit un site sur 2) sont quantifiées dans les sédiments. Ce sont les congénères de la famille des HAP (11 substances), des formes organiques de l’étain (2 substances), le plomb diéthyle et le congénère 209 des PBDE. Dans les DOM, les 22 substances quantifiées aux plus hautes fréquences (> 50%, soit un site sur 2) sont mesurées dans les sédiments. Ce sont des congénères de la famille des HAP dans (13 substances), des alkylphénols (3 substances : nonylphénols mono et diéthoxylés et 4-ter butylphénol), des formes organiques de l’étain (2 substances), des produits de métabolisation de l’insecticide DDT (2 produits), du plomb diéthyle et du congénère 209 des PBDE. L’étude de la répartition des plus fortes concentrations entre la métropole et les DOM montre que les 5 (sur 19) concentrations les plus élevées mesurées dans l’eau et les 6 (sur 47) plus fortes concentrations mesurées dans les sédiments sont trouvées dans les DOM. Les substances mesurées aux fortes fréquences sont observées dans le sédiment. La référence à la PNEC indique le dépassement de la norme pour 4 pesticides dans l’eau brute et 11 substances diverses dans les sédiments. L’exploitation des données par usage ou nature des substances montre que les plastifiants et les pesticides sont majoritaires dans les eaux brutes, à la fois en métropole et dans les DOM alors que ce sont les HAP qui dominent dans les sédiments, en métropole et dans les DOM.

Droits : 2014 ONEMA, Ifremer
http://archimer.ifremer.fr/doc/00259/36994/35483.pdf
http://archimer.ifremer.fr/doc/00259/36994/

Éditeur(s) : Société Nationale de Protection de la Nature
Résumé : Monitoring of French Polynesia coral reefs and their recent development.-French Polynesia, consisting of 118 islands in the centre of the Pacific Ocean, has more than 15 000 km(2) of reefs and lagoons managed by the local government. Tourism and pearl culture are the two main economic resources of the country. Polynesian coral reefs are extremely diverse and are among those for which we have thorough knowledge. The exploitation of local resources has been recorded for multiple decades and includes : coral materials, fishing, harvest and export of mother-of-pearl molluscs, pearl production, and ornamental fish. All over the country, many monitoring programmes have been launched to measure the health of reefs and the natural and anthropogenic perturbations that they suffer : hurricanes and seismic events, water quality, health of benthic and fish communities, pearl oyster pathology and radiobiology. These data, collected over the last few decades, allowed to define the relative importance of natural and anthropogenic degradation on reefs and lagoons, and to explain the present status of reefs at different spatial scales. Devastating hurricanes are rare (1903-1906, 1982-1983 and occasionally at other times), but they may annihilate outer slope coral communities on some islands. Bleaching events with considerable coral mortality at different geographical scales occurred mainly in 1991, 1994 and 2003. Outbreaks of Acanthaster destroyed numerous reefs (lagoons and outer slopes) from 1978-1982 and a new demographic wave began in 2006 at many Society islands. Eutrophication events only occurred occasionally and only in some lagoons. Whereas natural catastrophic events degrade the coral reef ecosystem across many islands, at the archipelago or even regional scale, anthropogenic degradation is limited to a few Society Islands, occurring rarely on atolls and not at all on those (one third) which are uninhabited. The main causes of reef degradation in some areas of Tahiti and Moorea include the embankment of fringing zones, coral mining, overfishing, absence of urban sewage treatment and the development of leisure and tourism activities. Because of its large geographical extent, one may conclude that major reef degradation in French Polynesia is caused by catastrophic natural events. On the other hand, anthropogenic degradation is more localized. Unfortunately, the synergistic effects of these causes of degradation prevent reefs from recovering. Optimum coral cover on French Polynesian outer reef slopes is between 50-60%. After a major destructive impact (hurricane, bleaching, Acanthaster) a reef is reduced to less than 10% coral cover, however if no more major disturbance events occur a reef will recover in about 12 years. Most of the 15 000 km(2) of reefs and lagoons in French Polynesia are in good health, and along with their neighbouring reefs in East and Central Pacific they are considered as the least degraded reefs worldwide and at a low risk of becoming degraded in the few next decades. However, we are more and more anxious about the future of reefs in the world particularly because present simulations predict that major impacts of climate change would include : elevation of sea surface temperatures, increase in the strength of hurricanes and acidification of seawater which will affect the formation of coral structures.
La Polynésie française, 118 îles au coeur du Pacifique, possède une surface de plus de 15 000 km2 de récifs et lagons gérés par le gouvernement polynésien. Le tourisme et la perliculture représentent les deux ressources économiques majeures du Pays. Les formations récifales très diversifiées sont parmi les mieux connues. Plusieurs suivis d'exploitation des ressources sont opérationnels depuis des décennies : granulats coralliens, pêche pour l'alimentation, collecte et exportation de mollusques nacriers, production de perles, poissons d'ornement. À l'échelle du Pays de très nombreux programmes de surveillance de l'état des récifs et des perturbations qu'ils subissent, naturelles et anthropiques, ont été mis en place : perturbations cycloniques et sismiques, qualité des eaux, état de santé des peuplements benthiques et ichtyologiques, pathologie des nacres, radiobiologie. Toutes ces données recueillies au fi l des décennies ont permis d'établir l'importance relative des dégradations naturelles et anthropiques sur les récifs et lagons polynésiens et d'expliquer leur état de santé actuel en considérant différentes échelles spatiales. Les périodes cycloniques dévastatrices pour les récifs sont rares (1903-1906, 1982-1983 et épisodiquement) mais les cyclones ont parfois anéanti les communautés coralliennes de pentes externes dans certaines îles. Les blanchissements suivis de mortalités importantes à des échelles spatiales diverses, ont été surtout ceux de 1991, 1994 et 2003. Les explosions démographiques d'Acanthaster ont détruit de nombreux récifs (lagons et pentes externes) en 1978-1982 et une nouvelle pullulation s'amplifie depuis 2006 dans plusieurs îles de la Société. Les crises dystrophiques n'ont perturbé qu'épisodiquement certains lagons. [...]
Revue d'Ecologie de la Terre et de la Vie (0249-7395) (Société Nationale de Protection de la Nature), 2008 , Vol. 63 , N. 1-2 , P. 145-177

Droits : 2008 Société Nationale de Protection de la Nature
http://archimer.ifremer.fr/doc/2008/publication-4558.pdf
http://archimer.ifremer.fr/doc/00000/4558/