15 research outputs found
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
Contamination assessment of arsenic and heavy metals in a typical abandoned estuary wetlandâa case study of the Yellow River Delta Natural Reserve
Essai collaboratif sur l'échantillonnage des sédiments de riviÚre : 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 lâEau (DCE, /2000/60/CE) et les directives filles (NQE, 2008/105/CE et 2013/39/UE) imposent aux Etats membres un contrĂŽle des sĂ©diments Ă une frĂ©quence raisonnable afin de fournir un nombre suffisant de donnĂ©es pour permettre une analyse fiable des tendances. Cela est primordial notamment pour les substances prioritaires hydrophobes qui tendent Ă sâaccumuler dans les sĂ©diments. Ce contrĂŽle est basĂ© sur lâanalyse de lâĂ©volution Ă long terme des concentrations des substances prioritaires en se fondant sur la surveillance de lâĂ©tat des eaux de surface. Il est demandĂ© aux Etats membres de prendre les mesures nĂ©cessaires pour veiller Ă ce que ces concentrations nâaugmentent pas de maniĂšre significative dans les sĂ©diments. Les programmes de surveillance doivent ĂȘtre construits de sorte quâune exploitation fiable et robuste des donnĂ©es soit possible. Ceci passe par une description prĂ©cise des objectifs du programme et par la mise en oeuvre dâune stratĂ©gie dâĂ©chantillonnage rĂ©pondant Ă ces objectifs. De plus, pour Ă©tablir des tendances spatiales ou temporelles, il est nĂ©cessaire de pouvoir comparer les donnĂ©es issues de ces programmes de surveillance. Une comparaison directe des donnĂ©es brutes nâest pas suffisante en raison de lâhĂ©tĂ©rogĂ©nĂ©itĂ© des sĂ©diments, des changements de nature du sĂ©diment au cours du temps ou encore des diffĂ©rences de nature des sĂ©diments entre sites. Il est donc nĂ©cessaire dâutiliser des techniques de normalisation afin dâexploiter les donnĂ©es. Ce rapport synthĂ©tise tout dâabord les exigences et les recommandations europĂ©ennes pour la surveillance des sĂ©diments continentaux, dans lâoptique dâune Ă©valuation des tendances spatio-temporelles de contamination. Puis, sur la base des connaissances actuelles, notamment celles reprises dans les guides techniques (europĂ©ens et AQUAREF), et de la littĂ©rature scientifique, les principales techniques de prĂ©lĂšvement, de prĂ©traitement des sĂ©diments, et les mĂ©thodes dâexploitation des donnĂ©es pour lâĂ©valuation des tendances spatiales et/ou temporelles ont Ă©tĂ© recensĂ©es et dĂ©crites. Enfin, Ă titre dâexemple, certaines mĂ©thodes dâexploitation des donnĂ©es ont Ă©tĂ© appliquĂ©es Ă des jeux de donnĂ©es de surveillance (sĂ©diments et matiĂšres en suspension) dans les cours dâeaux, afin de vĂ©rifier leur applicabilitĂ© pour lâĂ©valuation des tendances. Suite Ă ces travaux, lâĂ©laboration et la formalisation dâune mĂ©thodologie pratique dâĂ©valuation des tendances dans les sĂ©diments, associĂ©es au dĂ©veloppement et Ă lâutilisation dâoutils statistiques plus systĂ©matiques et/ou intĂ©grĂ©s apparaissent nĂ©cessaires