The impact of dam flushing event on dissolved trace elements concentrations: Coupling integrative passive sampling and discrete monitoring

International audienceSediments accumulation in reservoirs induces water storage capacities reduction and flood risks increases rendering dam flushing or dredging events compulsory for security reasons. Short transient events like dam flushing monitoring is still a great challenge because the suspended sediments and contaminants concentrations increases could occur over only few hours/days and cover tens of kilometres. Since 1942, 21 dam flushing events have been performed on the Upper Rhône River (from Lake Geneva in Switzerland to Lyon in France) in order to evacuate accumulated sediments behind the Verbois dam (Switzerland). We designed an original sampling strategy to assess the 2016 dam flushing event consequences on the spatio-temporal dynamics of dissolved trace elements concentration and to reveal how passive sampling monitoring (Diffusive Gradient in Thin films, DGT) could improve this evaluation. Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, As and Hg dissolved concentrations were monitored by discrete and passive sampling at 3 stations over 160 km downstream the Verbois dam. Since dissolved Fe, Cu, Cd, Cr, Pb, Zn and Hg concentrations did not show great variations during the flushing event, the DGT efficiency was not fully demonstrated for these elements. In contrast, a sharp increase of Mn, Ni, Co and As dissolved concentrations (up to 22 times) was recorded, resulting mainly from a release from resuspended sediment. The dissolved As increase was mainly caused by reduced arsenic (AsIII) increase, even monitored 160 km downstream the Verbois dam. The DGT measurements were highly representative of trace elements concentrations and As speciation dynamics in comparison with discrete sampling. Although relatively high dispersion was highlighted for some elements DGT measurements during the flushing event, we showed that DGTs are robust and powerful time-integrative tools to monitor many trace elements more efficiently than discrete sampling during a short transient event on a large spatial scale

Analyse bidimensionnelle “comprehensive” hors-ligne SECxRPLC-ICP-MS/MS pour l’analyse de matrices complexes

National audienc

Suitable interface for coupling liquid chromatography to inductively coupled plasma-mass spectrometry for the analysis of organic matrices. 2 Comparison of Sample Introduction Systems

International audienceLiquid chromatography (LC) coupled with a specific detection such as inductively coupled plasma-mass spectrometry (ICP-MS/MS) is a technique of choice for elementary speciation analysis for complex matrices. The analysis of organic matrices requires the introduction of volatile solvents into the plasma which is an analytical challenge for this coupling technique. Detection sensitivity can be significantly affected by instrumental limitations. Among those, we were interested in the solute dispersion into the interface located between LC and ICP-MS/MS. This interface consists in both a Sample Introduction System (SIS) and a possible flow splitter. This study, divided into two parts, investigated the analytical performance (in terms of sensitivity and efficiency) generated by the coupling of LC and ICP-MS in the specific case of organic matrices. In Part I [1], we previously discussed the impact of extra column dispersion on the performance of LC-ICP-MS, first from a theoretical point of view and next, by assessing extra-column dispersion in 55 published studies on LC-ICP-MS. It was shown that SIS was rarely optimized with respect to its contribution to extra-column band broadening. The critical impact of flow splitting on extra-column dispersion was also pointed out.The present Part II is dedicated to the experimental comparison of commercially available SIS by assessing extra-column band broadening and hence the contribution of SIS to the loss in both efficiency and sensitivity. It is shown that the peak variance, due to SIS, can vary from 10 to 8000 μL² depending on the combination of both nebulizer and spray chamber. Whereas the highest values (i.e. > 2000 μL²) are much too high in high performance liquid chromatography (HPLC), even the lowest values (i.e. < 100 μL²) can be inappropriate in ultra-high pressure liquid chromatography (UHPLC) as highlighted in this study. In light of these results, it appears that nebulizer and spray chamber have to be chosen together with respect to the chromatographic technique (HPLC or UHPLC) and that both peak dispersion and peak intensity depend on key parameters including SIS device geometry, flow rate entering the interface or spray chamber temperature

Comprehensive two-dimensional liquid chromatography with inductively coupled plasma mass spectrometry detection for the characterization of sulfur, vanadium and nickel compounds in petroleum products

International audienceThe petroleum industry is increasingly concerned with the conversion of vacuum residues as a consequence of decreased conventional crude oil availability. The compositional analysis of heavy oil products has become a key step in conversion processes, but the complexity of these oil matrices tends to increase with their boiling point. In this study, comprehensive two-dimensional liquid chromatography (LCxLC) coupled to inductively coupled mass spectrometry (ICP-MS/MS) is considered with a view to meet new requirements and to bring additional information regarding the species present in these matrices. In search for a high degree of orthogonality, two separation techniques involving two different retention mechanisms were evaluated: Size Exclusion Chromatography (SEC) and Reverse Phase Liquid Chromatography (RPLC). In SEC, the analytes are separated according to their molecular weight while according to their hydrophobicity in RPLC. The separation power of both individual separation techniques was first evaluated. Off-line and on-line LCxLC were compared on the basis of an optimization approach. It is shown that off-line SECxRPLC can provide, for the same analysis time of 150 min, a higher peak capacity (2600 vs 1700) than on-line RPLCxSEC while a similar dilution factor (close to 30) but also requires far fewer fractions to be analyzed (12 vs 400). Asphaltenes which constitute the heaviest fraction of crude oils (obtained from petroleum industry) were analyzed by the developed off-line SECxRPLC method. The resulting 2D-contour plots show that co-elutions could be removed leading, for the first time, to new information on high molecular weight species containing sulfur and vanadium

Two-year survey of specific hospital wastewater treatment and its impact on pharmaceutical discharges

International audienceIt is well known that pharmaceuticals are not completely removed by conventional activated sludge wastewater treatment plants. Hospital effluents are of major concern, as they present high concentrations of pharmaceutically active compounds. Despite this, these specific effluents are usually co-treated with domestic wastewaters. Separate treatment has been recommended. However, there is a lack of information concerning the efficiency of separate hospital wastewater treatment by activated sludge, especially on the removal of pharmaceuticals. In this context, this article presents the results of a 2-year monitoring of conventional parameters, surfactants, gadolinium, and 13 pharmaceuticals on the specific study site SIPIBEL. This site allows the characterization of urban and hospital wastewaters and their separate treatment using the same process. Flow proportional sampling, solid-phase extraction, and liquid chromatography coupled with tandem mass spectrometry were used in order to obtain accurate data and limits of quantification consistent with ultra-trace detection. Thanks to these consolidated data, an in-depth characterization of urban and hospital wastewaters was realized, as well as a comparison of treatment efficiency between both effluents. Higher concentrations of organic carbon, AOX, phosphates, gadolinium, paracetamol, ketoprofen, and antibiotics were observed in hospital wastewaters compared to urban wastewaters. Globally higher removals were observed in the hospital wastewater treatment plant, and some parameters were shown to be of high importance regarding removal efficiencies: hydraulic retention time, redox conditions, and ambient temperature. Eleven pharmaceuticals were still quantified at relevant concentrations in hospital and urban wastewaters after treatment (e.g., up to 1 μg/L for sulfamethoxazole). However, as the urban flow was about 37 times higher than the hospital flow, the hospital contribution appeared relatively low compared to domestic discharges. Thanks to the SIPIBEL site, data obtained from this 2-year program are useful to evaluate the relevance of separate hospital wastewater treatment

Biomonitoring chronic lead exposure among battery manufacturing workers in Tunisia

International audienc

Speciation of metals by sequential extractions of agricultural soils located near a dumpsite for prediction of element availability to vegetables

International audienc

Intégration des concentrations métalliques dissoutes lors d'un évènement hydrologique transitoire sur le Rhône : cas des opérations de gestion sédimentaires.

National audienc

Analyse de nanoparticules par Single Particle ICP MS en milieux organiques

International audienc

Elemental analysis in the refinery industry: total determination and speciation of contaminants using a triple quadrupole ICP/MS Agilent 8800

International audienc