An in situ intercomparison exercise on passive samplers for the monitoring of metals, polycyclic aromatic hydrocarbons and pesticides in surface water | Intercalibration in situ de capteurs passifs pour la surveillance des métaux, HAP et pesticides dans les eaux de surface

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA

International audience

إنجليزي. In the context of a scientific collaboration between expert laboratories, intercomparison exercises on passive samplers were organized in summer 2010. The main objective was to evaluate the usefulness of passive samplers for monitoring programs within the Water Framework Directive. More specifically, we wanted: (i) to evaluate comparability and variability of measurements with passive samplers, (ii) to evaluate validity of these samplers in various types of aquatic environments to sample different molecule families, and (iii) to allow the passive sampling technology transfer to water basin managers and routine laboratories. Sampling campaigns happened between April and July 2010 for the measurement of metals, polycyclic aromatic hydrocarbons (PAH) and pesticides in continental and marine surface waters. The passive samplers used included POCIS (Polar Organic Chemical Integrative Sampler), SPMD (Semi-Permeable membrane Device), membranes (LDPE, silicone), chemcatcher, MESCO (Membrane-Enclosed Sorptive Coating) for organic contaminants; and DGT (Diffusive Gradient in Thin Film) for metals. Two continental surface water sites (Beillant, Charente maritime and Ternay, Rhône) and one marine surface water site (Thau, Hérault) were sampled. A total of 24 laboratories participated, whose 13 were not French. Exposure duration were set at 7 days for metals, 14 days for pesticides and 21 days for PAH. Passive samplers were exposed in triplicates to characterize the repeatability of sampling. To evaluate the usefulness and limits of passive samplers, referent laboratories were in charge of chemical analysis of grab water samples collected during the campaigns. Moreover, to better understand results on passive sampling, we also measured flow velocity, temperature and physico-chemical parameters of the surface waters. As for example, we will present results on: Quality Controls (QC) performed by all participants on standard solutions to evaluate accuracy of chromatographic analysis step for the 24 participants, Quantities of micropollutants accumulated per passive samplers, Time weighted average (TWA) concentrations of micropollutants in water obtained from passive samplers and comparison with water concentration from grab samples, Analytical and data treatment strategy followed by participants to obtain TWA water concentration, Micropollutants fingerprints obtained with the different passive samplers.