Tests of three passive samplers for monitoring of groundwater contaminated by chlorinated solvents
Résumé
Context => Passive samplers applied to groundwater are synonymous with "no-purge sampling" (ITRC, 2007). They can be classified as: - Devices that rely on diffusion and sorption to accumulate contaminants in the sampler (time-integrated samples) - C1 ; - Devices that recover a grab well water sample (instantaneous measurement) - C2 ; - Devices that rely on diffusion of contaminants across the sampler membrane to reach and maintain equilibrium with medium - C3. Scientific literature shows the existence of many types of passive samplers. Studies on their effectiveness have been carried out in the USA, Germany, Denmark, etc. and they can be used in routine to monitor contaminated groundwaters. By contrast, no guidelines for the use of these samplers have been published yet in France. Objectives => We proposed to evaluate the metrological and economic relevance of passive samplers in the context of groundwater monitoring, especially for VOCs contaminations. Results => To evaluate their advantages/limitations, we tested three of them: - Passive Diffusion Bags (C3) (Vroblesky, 2001) ; - Ceramic dosimeters (C1) (Weiss, 2006) ; - SorbiCells (C1) (De Jonge, 2005). These samplers have been tested over a one-year period in an industrial site contaminated by chlorinated solvents. Parameters like water table level, exposure time of the samplers, levels of contamination, etc. are considered in the study. Nine campaigns of measurements are performed to evaluate the metrological quality of these samplers. Comparisons are carried out with conventional methods of sampling. The results will then be the subject of a comparison and statistical tests. Procedures for the use of passive samplers, including handling, laboratory calibration, field deployment, advantages/disadvantages will then be published in France.