Distribution of trace elements in waters and sediments of the Seversky Donets transboundary watershed (Kharkiv region, Eastern Ukraine)

International audienceThis paper reports on the aquatic chemistry of trace elements in terms of spatial and temporal distribution, but also pollution sources in the transboundary watershed of the Seversky Donets River (Ukraine/Russia). Bed sediments and filtered water were collected from the Udy and Lopan Rivers at sites from the river source in the Belgorod region (Russia) to rural and urban areas in the Kharkiv region (Ukraine) in May and August 2009. Priority trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn), an urban tracer (Ag) and additional metals (Co, Mo, V) and Th were measured in stream water and sediments. The low levels and variability of Th-normalized concentrations indicated the absence of geochemical anomalies in the upstream part of the rivers and suggested that these data represent a regional baseline for trace elements in bed sediments. In contrast, water and sediments within the city of Kharkiv were contaminated by Ag, Pb, Cd, Cu, Cr and Zn, which are mainly attributed to municipal wastewater inputs and urban run-off. Results of the environmental quality assessment showed that element concentrations in the sediments can be considered as potentially toxic to aquatic organisms in sites downstream of the wastewater discharges

Quantification and spatial distribution of trace element contamination in the Gironde fluvio- estuarine system

L’estuaire de la Gironde est affecté par une pollution polymétallique historique provenant de son bassin versant (affluent du Lot). L’analyse de 320 échantillons de sédiments couvrant l’ensemble de la surface estuarienne nous a permis d’établir les premières cartographies à haute résolution spatiale de la contamination métallique des sédiments de surface. Elles révèlent des zones d’accumulation préférentielle des ETM au niveau de la zone des îles en amont de l’estuaire et du chenal nord en aval de l’estuaire. Le facteur de contrôle dominant cette répartition est la granularité des sédiments.L’estimation des stocks métalliques potentiellement re-mobilisables, des facteurs d’enrichissement et de la toxicité potentielle du cocktail des ETM prioritaires nous ont permis d’évaluer un risque de toxicité faible à moyen des ETM vis-à-vis du biota. La contamination en ETM des bassins versants affluents de l’estuaire de la Gironde inclus dans le périmètre du SAGE Estuaire a été appréhendée en couplant sous SIG les caractéristiques typologiques de 57 bassins versants et la géochimie des sédiments prélevés à l’exutoire de ces bassins.Les anomalies les plus importantes concernent les bassins proches de l’agglomération bordelaise et correspondent au cortège des « traceurs urbains » : Ag, Cd, Cu, Hg, Sb et Zn, ainsi que Cu pour les bassins viticoles. L’étude des variations temporelles et spatiales des concentrations en ETM sur les chenaux drainant deux bassins versants agricoles montre des apports ponctuels ou chroniques en Ag,As, Cu et U attribués aux activités anthropiques. Les zones de marais jouent un rôle important dans la spéciation des ETM en lien avec les transformations de la matière organique (e.g. As). Des expérimentations de laboratoire ont permis de caractériser les processus affectant les ETM issus des sols agricoles lors de leur transfert et de leur transport dans les systèmes aquatiques. Les phénomènes de relargage à long terme de Cu soulignent le rôle important des colloïdes organiques dans la mobilité et la biodisponibilité potentielle de cet élément.The Gironde estuarine system is impacted by historic polymetallic pollution due to mining and smelting activities in the upper watershed. Based on a high spatial resolution sampling strategy, wepropose the first maps of trace element (TE) contamination in the surface sediment at the estuarine scale. The highest TE concentrations occurred in the North Channel in the downstream estuary and inthe island zone in the upper estuary. Estimation of potentially releasable TE fraction, of enrichment factors and a comparison between measured TE concentrations and sediment quality guidelines allow us to class a major part of the estuary as a low to medium priority zone in terms of potential toxicityfor aquatic organisms.The TE contamination in the intra-estuarine watersheds included in a project of water quality management of the Gironde estuary (SAGE), was assessed for 57 watersheds by coupling into GIS,typological characteristics of the watersheds and geochemical analyses of stream sediments. Highest anomalies were found for urban watersheds for which urban tracers were identified as Ag, Cd, Cu, Hg,Sb and Zn, and for vineyard watersheds with Cu. A study of temporal and spatial variations of TEconcentrations in two small agricultural watersheds lead us to identify inputs from point and diffusive sources, especially for Ag, As, Cu and U related to anthropogenic activities. Marsh areas also play an important role in TE reactivity mainly due to organic matter transformations. In laboratory experiments simulating the transportation of TE from agricultural soils to aquatic systems and the maturing process of soil particles in the stream help us to identify processes responsible for TE release in the environment. Long term release of copper was mainly attributed to organic colloid transformation which implies an increase in the mobility, and consequently, the potential bioavailability/toxicity of Cu for aquatic organisms

Quantification and spatial distribution of trace element contamination in the Gironde fluvio- estuarine system

L’estuaire de la Gironde est affecté par une pollution polymétallique historique provenant de son bassin versant (affluent du Lot). L’analyse de 320 échantillons de sédiments couvrant l’ensemble de la surface estuarienne nous a permis d’établir les premières cartographies à haute résolution spatiale de la contamination métallique des sédiments de surface. Elles révèlent des zones d’accumulation préférentielle des ETM au niveau de la zone des îles en amont de l’estuaire et du chenal nord en aval de l’estuaire. Le facteur de contrôle dominant cette répartition est la granularité des sédiments.L’estimation des stocks métalliques potentiellement re-mobilisables, des facteurs d’enrichissement et de la toxicité potentielle du cocktail des ETM prioritaires nous ont permis d’évaluer un risque de toxicité faible à moyen des ETM vis-à-vis du biota. La contamination en ETM des bassins versants affluents de l’estuaire de la Gironde inclus dans le périmètre du SAGE Estuaire a été appréhendée en couplant sous SIG les caractéristiques typologiques de 57 bassins versants et la géochimie des sédiments prélevés à l’exutoire de ces bassins.Les anomalies les plus importantes concernent les bassins proches de l’agglomération bordelaise et correspondent au cortège des « traceurs urbains » : Ag, Cd, Cu, Hg, Sb et Zn, ainsi que Cu pour les bassins viticoles. L’étude des variations temporelles et spatiales des concentrations en ETM sur les chenaux drainant deux bassins versants agricoles montre des apports ponctuels ou chroniques en Ag,As, Cu et U attribués aux activités anthropiques. Les zones de marais jouent un rôle important dans la spéciation des ETM en lien avec les transformations de la matière organique (e.g. As). Des expérimentations de laboratoire ont permis de caractériser les processus affectant les ETM issus des sols agricoles lors de leur transfert et de leur transport dans les systèmes aquatiques. Les phénomènes de relargage à long terme de Cu soulignent le rôle important des colloïdes organiques dans la mobilité et la biodisponibilité potentielle de cet élément.The Gironde estuarine system is impacted by historic polymetallic pollution due to mining and smelting activities in the upper watershed. Based on a high spatial resolution sampling strategy, wepropose the first maps of trace element (TE) contamination in the surface sediment at the estuarine scale. The highest TE concentrations occurred in the North Channel in the downstream estuary and inthe island zone in the upper estuary. Estimation of potentially releasable TE fraction, of enrichment factors and a comparison between measured TE concentrations and sediment quality guidelines allow us to class a major part of the estuary as a low to medium priority zone in terms of potential toxicityfor aquatic organisms.The TE contamination in the intra-estuarine watersheds included in a project of water quality management of the Gironde estuary (SAGE), was assessed for 57 watersheds by coupling into GIS,typological characteristics of the watersheds and geochemical analyses of stream sediments. Highest anomalies were found for urban watersheds for which urban tracers were identified as Ag, Cd, Cu, Hg,Sb and Zn, and for vineyard watersheds with Cu. A study of temporal and spatial variations of TEconcentrations in two small agricultural watersheds lead us to identify inputs from point and diffusive sources, especially for Ag, As, Cu and U related to anthropogenic activities. Marsh areas also play an important role in TE reactivity mainly due to organic matter transformations. In laboratory experiments simulating the transportation of TE from agricultural soils to aquatic systems and the maturing process of soil particles in the stream help us to identify processes responsible for TE release in the environment. Long term release of copper was mainly attributed to organic colloid transformation which implies an increase in the mobility, and consequently, the potential bioavailability/toxicity of Cu for aquatic organisms

Essai collaboratif sur l'échantillonnage des sédiments de rivière : résultats et recommandations

The Water Framework Directive (WFD, 2000/60/EC) and the 2008/105/EC and 2013/39/EU daughters directives ask the member states to monitor sediments at an adequate frequency to provide sufficient data for a reliable long-term trend analysis. This task is paramount, especially for priority substances that tend to accumulate in sediment. This monitoring is based on a long-term trend analysis of concentrations of priority substances thanks to data provided by the monitoring of surface water status. Member states shall take measures to ensure that such concentrations do not significantly increase in sediment. Monitoring programs shall be designed in order to allow a reliable and robust exploitation of the data. This induces an explicit description of the monitoring program objectives and the application of sampling strategies that meet these objectives. Moreover, to establish spatial or temporal trends, it should be ensured that the data provided by monitoring programs can be compared. A direct comparison of raw data is not sufficient because of sediment heterogeneity, modification of the sediment nature with time or differences in the nature of sediments sampled from different sites. Thus, the use of normalisation procedures is required to exploit data. This report takes an inventory of European requirements and recommendations for continental sediment monitoring with a view to evaluate spatial and temporal contamination trends. Based on current knowledge and examples from scientific publications, a report of sampling technics, of sediment preprocessing and data exploitation methods to evaluate spatial and/or temporal trends is drawn up. Then, the most promising data exploitation methods will be applied to surface water monitoring data set (sediments and suspended solids) in order to evaluate their relevance for long-term trend analysis. Following this study, the design and the formalization of guidelines for the evaluation of long-term trends in sediments, alongside with the development and the use of more systematic and/or integrated statistical tools come as a necessity.La Directive Cadre sur l’Eau (DCE, /2000/60/CE) et les directives filles (NQE, 2008/105/CE et 2013/39/UE) imposent aux Etats membres un contrôle des sédiments à une fréquence raisonnable afin de fournir un nombre suffisant de données pour permettre une analyse fiable des tendances. Cela est primordial notamment pour les substances prioritaires hydrophobes qui tendent à s’accumuler dans les sédiments. Ce contrôle est basé sur l’analyse de l’évolution à long terme des concentrations des substances prioritaires en se fondant sur la surveillance de l’état des eaux de surface. Il est demandé aux Etats membres de prendre les mesures nécessaires pour veiller à ce que ces concentrations n’augmentent pas de manière significative dans les sédiments. Les programmes de surveillance doivent être construits de sorte qu’une exploitation fiable et robuste des données soit possible. Ceci passe par une description précise des objectifs du programme et par la mise en oeuvre d’une stratégie d’échantillonnage répondant à ces objectifs. De plus, pour établir des tendances spatiales ou temporelles, il est nécessaire de pouvoir comparer les données issues de ces programmes de surveillance. Une comparaison directe des données brutes n’est pas suffisante en raison de l’hétérogénéité des sédiments, des changements de nature du sédiment au cours du temps ou encore des différences de nature des sédiments entre sites. Il est donc nécessaire d’utiliser des techniques de normalisation afin d’exploiter les données. Ce rapport synthétise tout d’abord les exigences et les recommandations européennes pour la surveillance des sédiments continentaux, dans l’optique d’une évaluation des tendances spatio-temporelles de contamination. Puis, sur la base des connaissances actuelles, notamment celles reprises dans les guides techniques (européens et AQUAREF), et de la littérature scientifique, les principales techniques de prélèvement, de prétraitement des sédiments, et les méthodes d’exploitation des données pour l’évaluation des tendances spatiales et/ou temporelles ont été recensées et décrites. Enfin, à titre d’exemple, certaines méthodes d’exploitation des données ont été appliquées à des jeux de données de surveillance (sédiments et matières en suspension) dans les cours d’eaux, afin de vérifier leur applicabilité pour l’évaluation des tendances. Suite à ces travaux, l’élaboration et la formalisation d’une méthodologie pratique d’évaluation des tendances dans les sédiments, associées au développement et à l’utilisation d’outils statistiques plus systématiques et/ou intégrés apparaissent nécessaires

Silver behaviour along the salinity gradient of the Gironde Estuary

International audienceDissolved and particulate Ag concentrations (Ag D and Ag P , respectively) were measured in surface water and suspended particulate matter (SPM) along the salinity gradient of the Gironde Estuary, South West France, during three cruises (2008-2009) covering contrasting hydrological conditions, i.e. two cruises during intermediate and one during high freshwater discharge (~740 and~2,300 m 3 /s). Silver distribution reflected non-conservative behaviour with 60-70 % of Ag P in freshwater particles being desorbed by chlorocomplexation. The amount of Ag P desorbed was similar to the so-called reactive, potentially bioavailable Ag P fraction (60±4 %) extracted from river SPM by 1 M HCl. Both Ag P (0.22±0.05 mg/kg) and Ag P /Th P (0.025-0.028) in the residual fraction of fluvial and estuarine SPM were similar to those in SPM from the estuary mouth and in coastal sediments from the shelf off the Gironde Estuary, indicating that chlorocomplexation desorbs the reactive Ag P. The data show that desorption of reactive Ag P mainly occurs inside the estuary during low and intermediate discharge, whereas expulsion of partially Ag P-depleted SPM (Ag P /Th P 0.040) during the flood implies ongoing desorption in the coastal ocean, e.g. in the nearby oyster production areas (Marennes-Oléron Bay). The highest Ag D levels (6-8 ng/ L) occurred in the mid-salinity range (15-20) of the Gironde Estuary and were decoupled from freshwater discharge. In the maximum turbidity zone, Ag D were at minimum, showing that high SPM concentrations (a) induce Ag D adsorption in estuarine freshwater and (b) counterbalance Ag P desorp-tion in the low salinity range (1-3). Accordingly, Ag behaviour in turbid estuaries appears to be controlled by the balance between salinity and SPM levels. The first estimates of daily Ag D net fluxes for the Gironde Estuary (Boyle's method) showed relatively stable theoretical Ag D at zero salinity (Ag D 0 0 25-30 ng/L) for the contrasting hydrological situations. Accordingly, Ag D net fluxes were very similar for the situations with intermediate discharge (1.7 and 1.6 g/day) and clearly higher during the flood (5.0 g/day) despite incomplete desorption. Applying Ag D 0 to the annual freshwater inputs provided an annual net Ag D flux (0.64-0.89 t/year in 2008 and 0.56-0.77 t/year in 2009) that was 12-50 times greater than the Ag D gross flux. This estimate was consistent with net Ag D flux estimates obtained from gross Ag P flux considering 60 % desorption in the estuarine salinity gradient

Patients with drug-free long-term graft function display increased numbers of peripheral B cells with a memory and inhibitory phenotype

Several transplant patients maintain stable kidney graft function in the absence of immunosuppression. Here we compared the characteristics of their peripheral B cells to that of others who had stable graft function but were under pharmacologic immunosuppression, to patients with chronic rejection and to healthy volunteers. In drug-free long-term graft function (DF) there was a significant increase in both absolute cell number and frequency of total B cells; particularly activated, memory and early memory B cells. These increased B-cell numbers were associated with a significantly enriched transcriptional B-cell profile. Costimulatory/migratory molecules (B7-2/CD80, CD40, and CD62L) were upregulated in B cells; particularly in memory CD19+IgD−CD38+/−CD27+ B cells in these patients. Their purified B cells, however, responded normally to a polyclonal stimulation and did not have cytokine polarization. This phenotype was associated with the following specific characteristics which include an inhibitory signal (decreased FcγRIIA/FcγRIIB ratio); a preventive signal of hyperactive B-cell response (an increase in BANK1, which negatively modulates CD40-mediated AKT activation); an increased number of B cells expressing CD1d and CD5; an increased BAFF-R/BAFF ratio that could explain why these patients have more peripheral B cells; and a specific autoantibody profile. Thus, our findings show that patients with DF have a particular blood B-cell phenotype that may contribute to the maintenance of long-term graft function