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International audience; Over one year study (12 campaigns), particulate arsenic and dissolved inorganic arsenic (total inorganic Asi and arsenite As(III)) levels were determined along the whole salinity gradient of the Penzé estuary (12 stations) in Brittany (France). Concentrations, in the range 2-26 nM and 3-56 μg g− 1 for dissolved inorganic and particulate arsenic, respectively, were relatively high in comparison to pristine systems and were attributed to pig and poultry farming activities taking place in the catchment area. Our results show that variations of dissolved inorganic and particulate arsenic up to mid-estuary were significantly linked to fluvial inputs, these latter being controlled by water discharge and precipitations. Arsenite variations over a large salinity range (S > 4) were controlled by those of the marine end-member mainly through bacterial processes. Removal of dissolved species within the water column by adsorption on oxide material was found to be minimal while arsenic fluxes from the sediment control arsenate and arsenite levels in the upper part of the estuary.

International audience; In this study, direct determination of mercury at the nanogram per liter level in the complex seawater matrix by imaging time-resolved electrothermal atomization laser-excited atomic fluorescence spectrometry (ITR-ETA-LEAFS) is described. In the case of mercury, the use of a nonresonant line for fluorescence detection with only one laser excitation is not possible. For measurements at the 253.652 nm resonant line, scattering phenomena have been minimized by eliminating the simultaneous vaporization of salts and by using temporal resolution and the imaging mode of the camera. Electrothermal conditions (0.1 M oxalic acid as matrix modifier, low atomization temperature) have been optimized in order to suppress chemical interferences and to obtain a good separation of specific signal and seawater background signal. For ETA-LEAFS, a specific response has been obtained for Hg with the use of time resolution. Moreover, an important improvement of the detection limit has been obtained by selecting, from the furnace image, pixels collecting the lowest number of scattered photons. Using optimal experimental conditions, a detection limit of 10 ng L–1 for 10 μL of sample, close to the lowest concentration level of total Hg in the open ocean, has been obtained.

International audience; This study examined the potential metal pollution induced by the accidental spill of different acids into seawater. The acids sink to the bottom according to their densities and subsequently react with marine sediments. The acids selected for this study were acetic, hydrochloric, nitric, sulfuric, and phosphoric acids; the metallic elements selected were Cr, Cu, Fe, Mn, Pb and Zn. The sediment was collected in Brest Harbour. The percentages of metals released from this sediment in the presence of various concentrations of acids in seawater were important; concentrations of approximately 7 mg L(-1) for Mn and 60 mg L(-1) for Zn were observed under our experimental conditions. We also examined the rate of release of these metals from the sediment into the seawater in the presence of the different acids and under different experimental conditions. We found that most of the metallic elements were released from the sediments into the seawater during the first fifteen minutes of exposure. After this time, a high degree of pollution was induced if acids leached into seawater were not rapidly diluted.

International audience; Coal is currently becoming an increasingly interesting fossil energy resource and that is the reason why its maritime transport, and hence the risk of collier accidents, increase. In this work, the environmental impact of an accidental coal immersion at sea is studied: the physicochemical effects are estimated using innovative experimental setups--a laboratory seawater canal called "polludrome" is used to evaluate the behaviour of coal particles submitted to a seawater flow, and a specifically designed tub is used to study the physicochemical consequences induced when coal is introduced into continuously renewed seawater. When coal is introduced into seawater, the most easily visible consequences are physical: fine coal particles reduce the daylight penetration up to 100% and move along with the flow, and coal chunks accumulate on the floor. Chemical effects are also measured: humic matters are dissolved from coal into seawater (up to 2 mg L(-1)), but no release of polycyclic aromatic hydrocarbons is evidenced. Some inorganic compounds are dissolved, among which manganese, whose concentrations can reach 1 microg L(-1). Fortunately, the results show that the environmental impact of this type of accident would remain limited.

Weekly or half-monthly bulk rainwater samples were collected over 3 yr (1993–1995) at Porspoder, an Atlantic station near Brest, France. They were analyzed for 0.08 M HNO3-leachable trace metals Cd, Cu, Fe, Mn, Ni, Pb and Zn by direct electrothermal atomic absorption spectrometry. Major ions and nitrogen species (NO3- and NH4+) in precipitation were determined by ion chromatography. In coastal precitation, a high correlation was observed for major ions having a seawater origin (Na+, CL- and Mg2+. Zn, Cd, Cu, Ni and Pb were well correlated indicating their anthropogenic origin. In the case of nitrogen species and nssSO42- a high correlation with Zn was observed, taken as an anthropogenic pollution tracer. Major ions and nitrogen species were determined according to wind sector direction showing clearly the impact of the pollution at this station attributed to continental air masses. A relative constancy of pH values in all wind directions was observed. Due to an important oceanic influence, trace metal concentrations and annual deposition densities were significantly lower at Porspoder than at North Sea coastal stations. In the case of nitrogen species, the relatively higher concentration levels probably indicated a significant local agricultural contribution.

International audience; A new approach is proposed to optimize some instrumental electrothermic parameters, i.e. injected volume, calcination duration, calcination and atomization temperatures, gas flow, in electrothermal atomic absorption spectrometry. It is based on the monitoring of the detection limit estimation variation by using an unconventional experimental design well adapted to a particular experimental domain. This method was tested on Cd, Mn and Cu in sea water. By comparison with the default operating conditions, the limits of detection were improved in some cases and always obtained on carrying out less experiments than usual. Copyright (C) 1998 Elsevier Science B.V.

A new approach is proposed to optimize some instrumental electrothermic parameters, i.e. injected volume, calcination duration, calcination and atomization temperatures, gas flow, in electrothermal atomic absorption spectrometry. It is based on the monitoring of the detection limit estimation variation by using an unconventional experimental design well adapted to a particular experimental domain. This method was tested on Cd, Mn and Cu in sea water. By comparison with the default operating conditions, the limits of detection were improved in some cases and always obtained on carrying out less experiments than usual.

The vertical distribution of cadmium, copper and lead was studied in the 0–500 m layer of the Eastern Alboran Sea. The concentrations measured compare favourably with recent data for the neighbouring area (53 pM < Cd < 124 pM; 1.4 nM< Cu < 2.8 nM, and 90 pM < Pb < 310 pM). The analysis of six profiles showed the presence of a sub-surface water mass, the northwestern Mediterranean Water (NWMW, 75-30 m), with high concentration of trace metals. Metal-salinity relationships, typified by cadmium, showed that the Atlantic surface waters (ASW) with low metal concentrations before entering the Mediterranean Sea become enriched with metals from some as yet not clearly understood source near the Straits of Gibraltar. The salinity-Cd relationship, taken together with flux rates of salt and Cd, however, shows that the Modified Atlantic water (MAW) gains its high metal concentrations during its transit in the Alboran Sea principally from a mixing with the underlying metal-rich NWMW.

International audience; This work presents spectroscopic properties of some Endocrine Disrupting Compounds (EDCs), frequently found in food and in natural water. Studied molecules belong to the groups of phenolic and phthalate EDCs. In a first part, we have examined their absorption and fluorescence properties. Fluorescence emission wavelengths are about 300 nm for phenolic compounds and 360 nm for phtalate compounds; main excitation wavelengths being comprised between 210 nm and 230 nm. Fluorescence lifetimes measured are short (about 4 ns) and the fluorescence quantum yield has been determined. In a second part, to avoid the time consuming solvent extraction step, an analytical application to evaluate the performance of a direct analysis by laser induced fluorescence spectroscopy of ECDs traces in tap water and in raw water is presented. Good detection limits have been obtained, i.e.: 0.35 µg.L−1 of chlorophenol in tap water, which are always lower than the reported Predictive Non Efficient Concentration (PNEC).

In the present study, seven colloidal fractions of lead (Pb) were analysed along the mixing zone of the Penzé estuary over the Year 2009, with the aim to provide some insight into the mechanism that removes the metal from the 300 kDa) and was removed in the salinity range 0–10 from all of the size fractions where it was significantly found. Because the colloidal fractionation of Pb was strongly linked to that of iron (Fe) and humic substances (HS), the removal of Pb in the mixing area must occur under flocculation of organomineral complexes. A key period corresponding to the first strong autumnal precipitations was also revealed in the present work. At this time of the year, the mobilisation of Pb (and Fe) from catchment soils is enhanced by the mobilisation of HS and the metal is associated with smaller colloids (30–300 kDa).

International audience; Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L(-1) (20 microL, 3sigma) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3sigma) of 3 ng L(-1) (i.e. 54 pM) for total Fe concentration with the use a 20 microL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 microg L(-1)) seawater sample were in good agreement with the certified values.

International audience; To gain more insight into the impact of zinc on the primary metabolites in rapeseed, plants were regenerated in vitro in the presence of zinc (0.1–1 mM), acclimatized, transferred to a greenhouse, and treated with 2 mM ZnSO4. The main metabolites, including soluble carbohydrates and free amino acids, were analyzed by nuclear magnetic resonance spectroscopy, and further confirmed by spectrophotometry and enzymatic analyses. Exposure of these greenhouse-grown plants to ZnSO4 led to both a significant rise of the total amino acid level and an increase of proline accumulation in the different tissues. Moreover, the control plants, regenerated without zinc stress, exhibited a significant reduction of soluble carbohydrate levels, whereas the plants derived from Zn-treated regenerants exhibited significantly higher levels of both glucose and sucrose. These levels increased proportionally with the Zn concentration in the regeneration step.

International audience

Dissolved cadmium and copper species were measured in the Loire estuary and the North Biscay Bay continental shelf (France) in spring 2002. Metal behaviours along the salinity gradient, metal fluxes from the Loire system and surface distributions on the continental shelf were described and compared with the ones obtained at a period of higher discharge (i.e., winter 2001). Vertical distributions at different stations were also examined with the aim to assess whether the Loire inputs affect the Cu and Cd speciation over the continental shelf. In the Loire estuary, different metal behaviours were observed from winter. Cu and its various species mostly followed a theoretical dilution line whereas a Cd addition composed of chloro- and organic complexes was observed. According to our estimations, the Cu flux was composed, as in winter, of 40% hydrophobic organic complexes. On the other hand, Cd organic complexes accounted for less in the total dissolved metal flux than they did in winter (55 and 78% for spring and winter, respectively). On the continental shelf, a C18Cu-to-TDCu ratio of 40% was observed in the stratified area under Loire influence. For Cd, the organic fraction was relatively important in the surface waters near the mouth of the estuary and decreased deeper and seaward. Thus, the Cu and Cd speciation on the North Biscay Bay continental shelf are firstly determined by the extent of the estuarine plume. Beyond the estuarine influence, biological processes appeared to be the origin of the observed variations.

Optimization of the furnace parameters for electrothermal atomization of mercury leads to a characteristic mass of 20 pg in aqueous solution and 30 pg in chloroform extracts (with Zeeman correction). With a single-step solvent extraction from 100 ml of sample, performed in the sampling vessel, and direct injection of 400 microl of the extract into the furnace, a characteristic concentration of approximately 0.8 ng/l. is reached.

International audience; Whenever immersed in seawater after a collier accident, a fossil fuel such as coal could become a source of pollution to the marine environment. To study the effect of such a contamination, four coal samples from different origins were used. A first analysis on those coals enabled us to determine the content of polycyclic aromatic hydrocarbons. Seawater was then mixed with coal to study the organic matter released from coal into seawater. Fluorescence was used for its sensitivity to aromatic compounds, with the additional purpose of evaluating the relevance of using an immersed fluorescence probe to monitor water pollution. Excitation-emission matrices were recorded and the excitation-emission wavelength range corresponding to the highest fluorescence intensity was 230 nm/[370 nm; 420 nm]. The samples with coal happened to fluoresce more than the coal-free samples, the difference depending on the coal origin. The fluorescence intensity increased with coal mass, up to some limit. The particle size also influenced the fluorescence intensity, the finest particles releasing more fluorescing substances, due to their higher exchange surface. When seawater percolated through coal, the samples fluoresced highly at the beginning, and then the fluorescence intensity decreased and reached the seawater level. However, even with a 10 ns acquisition time shift, the fluorescence spectra were not specific enough to show the presence of PAHs in the samples, which were too diluted to be detected, whenever released from coal into seawater. The lifetimes of the seawater and of the coal samples were respectively 4.7 and 3.8 ns, indicating that the substances released from coal mainly consisted of short-lived fluorescing substances, such as natural humic or fulvic substances. Consequently, the presence of coal does not seem to be too detrimental to the marine environment, and a direct fluorescence probe could be used to monitor the seawater organic charge increase due to the immersion of coal in seawater.

Lake Baringo, a freshwater lake in the central Kenya Rift Valley, is fed by perennial and ephemeral rivers, direct rainfall, and hot springs on Ol Kokwe Island near the centre of the lake. The lake has no surface outlet, but despite high evaporation rates it maintains dilute waters by subsurface seepage through permeable sediments and faulted lavas. New geochemical analyses (major ions, trace elements) of the river, lake, and hot spring waters and the suspended sediments have been made to determine the main controls of lake water quality. The results show that evaporative concentration and the binary mixing between two end members (rivers and thermal waters) can explain the hydrochemistry of the lake waters. Two zones are recognized from water composition. The southern part of the lake near sites of perennial river inflow is weakly influenced by evaporation, has low total dissolved species (TDS), and has a seasonally variable load of mainly detrital suspended sediments. In contrast, waters of the northern part of the lake show evidence for strong evaporation (TDS of up to eight times inflow). Authigenic clay minerals and calcite may be precipitating from those more concentrated fluids. The subaerial hot-spring waters have a distinctive chemistry and are enriched in some elements that are also present in the lake water. Comparison of the chemical composition of the inflowing surface waters and lake water shows (1) an enrichment of some species (HCO3−, Cl, SO42−, F, Na, B, V, Cr, As, Mo, Ba and U) in the lake, (2) a depletion in SiO2 in the lake, and (3) a possible hydrothermal origin for most F. The rare earth element distribution and the F/Cl and Na/Cl ratios give valuable information on the rate of mixing of the river and hydrothermal fluids in the lake water. Calculations imply that thermal fluids may be seeping upward locally into the lake through grid-faulted lavas, particularly south of Ol Kokwe Island. Copyright © 2006 John Wiley & Sons, Ltd.

International audience; The electrochemical reduction of the imide complex [Mo2(cp)2(μ-SMe)3(μ-NH)]+ (1+) has been investigated in THF and MeCN electrolytes by cyclic voltammetry, controlled-potential electrolysis and coulometry. In the absence of free protons, the electrochemical reduction produces the amide derivative [Mo2(cp)2(μ-SMe)3(μ-NH2)] (2) after consumption of 1 F mol-1 of 1+. In THF in the presence of acid, the reduction of 1+ occurs through a two-electron process. The presence of acid also results in the shift of the equilibrium between 1+ and amide dication 22+ (MeCN electrolyte) or induces an isomerisation of the imide ligand (THF electrolyte). This allows the electrolysis to be conducted at a potential 600 mV less negative than the reduction potential of 1+. Controlled-potential electrolyses in the presence of acid (2 equiv HTsO) produce the ammine derivative. Ammonia is released from these compounds either by coordination of the solvent (MeCN electrolyte) or by the binding of chloride to the ammine-tosylate complex (electrolyses in THF in the presence of acid and chloride). The final products, isolated almost quantitatively (>95%), are [Mo2(Cp)2(μ-SMe)3(MeCN)2] + and [Mo2(cp)2(μ-SMe)3(μ-Cl)], respectively.

International audience; In this study, Se(IV) was determined in seawater by flow injection hydride generation, trapping within the graphite furnace, followed by electrothermal atomic absorption spectrometry. The optimized protocol permitted a preconcentration factor of 1000 lowering the detection limit of Se(IV) in seawater to about 1.5 ng l-1 for a 25 ml sample volume. Because this technique is specific to Se(IV), various physico-chemical treatments leading to the conversion of other chemical forms into Se(IV) were investigated. Thermal and UV irradiation treatments of seawater samples in acidic or basic medium permitted the conversion of Se(-II)-selenomethionine and Se(VI) to Se(IV). Based on the different responses of selenium species towards the photochemical treatments, an operational speciation model of selenium species in seawater is proposed. According to our analytical protocol, 21 ng l-1 Se(VI), 10 ng l-1 Se(IV) and 13 ng l-1 organic Se-(II) species were determined in a coastal surface seawater collected near Brest.

Cet article decrit brievement les travaux realises dans le cadre general de la commission de Paris (PARCOM), dont les objectifs sont de mettre en œuvre les moyens de lutte contre la pollution marine d’origine tellurique. On rappelle plus particulierement les activites du sous-groupe de travail ATMOS, dont la mission pilote consiste a prendre en consideration les apports atmospheriques de polluants aux eaux de la convention et de les comparer aux autres apports. Parmi ces polluants, les metaux lourds de la « liste grise » (Cu, Pb, As, Ni, Cr, Zn) contenus dans la retombee humide, ainsi que les substances majeurs comme NO3- NH4+ font aujourd’hui partie d’un programme exhaustif de surveillance de l’atmosphere (CAMP), etabli a partir de plusieurs stations cotieres pour la plupart reparties autour de la mer du nord. On se propose ainsi de decrire les differents aspects du protocole s’y rattachant, puis de rapporter les resultats des differents exercices d’intercalibration des methodes d’analyses et d’echantillonnage des retombees humides realisees dans le cadre de ce programme ainsi que des donnees recentes enregistrees a la station francaise F et comparees a celles des autres stations du reseau.

A simple statistical calculation, confirmed experimentally, shows that in Zeeman-effect electrothermal atomic absorption spectrometry the value of the integrated absorbance [graphic omitted] measured during a time t in the absence of neutral atoms can be broken down into two terms according to [graphic omitted] In this relationship mi is a constant, different for each atomization indicated by the index i, and x is a random value whose standard deviation can be calculated from the standard deviation and the number of measurements of the instantaneous absorbance. The calculation of mi allows one to decrease the error due to the integration of the blank signal and, therefore, to decrease the detection limit. If a non-negligible variation of the mi value is induced in the atomization step, calculation of mi after this step is more advisable. For the tested apparatus, the proposed post-atomization correction improves the accuracy of measurements and reduces the instrumental detection limit (IUPAC). An improvement by a factor of 5 is obtained, for example, for the detection limit of aluminium with an integration time of 3 s. Moreover, it has been shown for manganese and aluminium that the value of the detection limit obtained after correction is very similar to that calculated from a single atomization using the following equation resulting from statistical approximations: [graphic omitted] where s is the standard deviation of the instantaneous blank absorbances, Ts the sampling rate, tint the integration time, m the mass of metal injected and QA the corresponding measured integrated absorbance. The use of this equation, which is based on the measurement of the real experimental noise from one atomization, can offer an important saving of time.

The determination of zinc in sea-water using an electrothermal atomic absorption spectrometry system with Zeeman-effect background correction is presented. The influence of various chloride and nitrate salts on the atomization signal of zinc was examined. In chloride medium particularly, the interference effect induced through losses of zinc chloride, by the thermohydrolysis of magnesium chloride and simultaneous generation of HCl during the pyrolysis step is noted. In nitrate medium, zinc is more stabilized by Mg > Ca > Na > NH+4. The effect of various inorganic and organic acids, used as chemical modifiers, on the atomization of zinc and background absorption signals in sea-water were examined. In unmodified sea-water, a Zeeman interference effect related to the vaporization of the chloride matrix leading to a systematic under-compensation and consequently to erroneous zinc concentration values was observed. In sea-water, modified with 1 mol l–1 nitric acid, a spectral Zeeman interference effect induced by the Zeeman splitting of the absorption bands of NO molecules generated during the decomposition–reduction of nitrate was observed; the induced over-compensation is eliminated by selective pyrolysis at about 850 °C. The chemical interference effect (25%) is related to the simultaneous vaporization of zinc and sodium oxides; the detection limit (3σ) being about 80 ng l–1 for a 10 µl injected volume of sea-water. In sea-water modified with 0.7 mol l–1 oxalic acid, there is no significant interference effect and the detection limit in this medium is about 60 ng l–1 for a 10 µl injected volume of sea-water.

A method for the determination of cadmium in sea-water using an electrothermal atomization atomic absorption spectrometry system with Zeeman-effect background correction is presented. The effect of various inorganic and organic acids, used as chemical modifiers, on the atomization of cadmium and the sea-water background absorption signals were examined. Of all the different modifiers studied, oxalic acid suppresses chloride interference, promotes a lower atomization temperature and does not introduce any simultaneous significant background absorption signal, and was therefore of particular interest. Optimization of the experimental conditions gave a characteristic mass of 0.23 pg. For an injection of 99 µl of sea-water into the furnace, the detection limit was 3 ng l–1.

(Copper signals from seawater matrices in electrothermal atomic absorption spectrometry. Part 1: study of the effects of principal inorganic ions.) The effects of the main inorganic ions of seawater (Na + , Mg 2+ , Ca 2+ , Cl − , SO 2− 4 ), and of nitrate as modifier, on the electrothermal atomic absorption spectrometric signal of copper are studied. Sodium chloride, sulfate or nitrate, magnesium chloride or nitrate, and calcium chloride can cause serious interferences. Thermal treatment at about 700°C prevents the interference of MgCl 2 by its hydrolysis. Ashing can be done without loss of copper at higher temperatures in the presence of sulfate salts (1300°C) and nitrate salts (1200°C) than in the presence of chloride salts (1100°C). This is ascribed to the stabilising effect of oxides and sulfides. A study of the influence of two-component matrices, MCl-MNO 3 or MCl-MSO 4 , on the atomization signal of copper confirms this stabilizing effect which adds to the decrease in interference connected with removal of chloride in acidic medium.

(Copper signals from seawater matrices in electrothermal atomic absorption spectrometry. Part 2: model for phenomena observed with sea water.) A model to explain the variations of copper signals in seawater is proposed on the basis of the results of Part 1 of this study and data obtained by ashing simulated seawaters under different conditions. The model is confirmed by the results found with nitric of sulfuric acid as modifier. In this model, ashing at 800°C hydrolyses MgCl 2 to MgO, and the consequent formation of sodium sulfide from the matrix stabilizes the copper in the furnace. The addition of a small nitrate concentration (0.2 M) induces, when magnesium is present, a complementary decrease of the interference.

The non-atomic absorption signals obtained from 9 sodium salts from a graphite atomizer are examined. The influence of nitric, sulfuric and phosphoric acids on NaCl matrix as well as the influence of Ca, Ba, Sr, Mg and Pt salts on Na2SO4 matrix are studied. The elimination of NaCl and Na2SO4 matrix has been obtained. En spectrophotometrie d'absorption atomique sans flamme la presence d'une matrice se traduit dans de nombreux cas lors de l'atomisation d'un element par l'existence d'une absorption non specifique qu'il convient de differencier avec exactitude de l'absorption specifique. Differents procedes ont ete developpes (arc deuterium, effect Zeeman.) permettant de realiser une correction avec une justesse en regle generale d'autant meilleure que les variations d'amplitude sont moins rapides. Dans la pratique, il eest tres rare que le mode operatoire utilise ne se traduise pas par de faibles surcorrections ou meme sous-corrections perturbant gravement l'exactitude d'un dosage au voisinage des l...

L'addition de tres faibles concentrations de platine(IV) a des solutions de differents elements metalliques (Na, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Pb) modifie l'atomisation de ces elements en spectrophotometrie d'absorption atomique sans flamme. Deux effets sont observes : une evolution de la forme des massifs d'absorption associee a des variations de sensibilite et un accroissement des temperatures d'atomisation des metaux.

We have evaluated for iodine, silver(I), chloride, bromide, iodide and triiodide, the activity coefficients for the transfer from water to its mixtures with ethylene carbonate at 40°C. The determination of the transfer parameters for ionic species is based on the Strehlow hypothesis relative to the ferrocene-ferricinium system. The results obtained allow us to confirm that: the silver(I) cation is more solvated by water than by ethylene carbonate; the anions which are hydrogen bond acceptors (Cl − , Br − , I − ) are more solvated by water than by ethylene carbonate and its aqueous mixtures; the affinity of the iodine molecule and the triiodide ion, which are large and polarizable species, is greater for ethylene carbonate and its aqueous mixtures than for water. In addition, this study and the comparison with water+propylene carbonate mixtures confirm the anomalous behaviour of these last media close to the miscibility gap.