Détermination des cinétiques d'accumulation et des taux d'échantillonnages pour 56 micropolluants organiques polaires et évaluation de 5 PRC potentiels avec le POCIS "pharmaceutiques"

Abstract

International audiencePOCIS (Polar Organic Chemical Integrative Sampler) is a recent integrative sampler made for sampling polar organic micropollutants in water. It is still in development concerning its domain of validity (e.g., molecules sampled, type of water studied, optimal exposure duration) and its performances (molecules sampling rates, repeatability, accuracy of the evaluation of time-weighted average concentrations - TWAC). In order to obtain in situ TWAC, POCIS needs to be calibrated in laboratory for each molecule of interest. In this work, we performed laboratory calibration of POCIS for 5 alkylphenols, 9 hormones, 11 pesticides, 27 pharmaceuticals, 3 phenols and 1 UV filter in a flow-through system. The system is composed of 2 aquaria (50 L) containing: i) spiked tap water (circa 3 µg/L for each studied molecule) and non-spiked POCIS, for the determination of accumulation kinetics or ii) non-spiked tap water and spiked POCIS, for the determination of desorption kinetics. We present results for the different studied molecules, including the duration of linear accumulation phase, sampling rates and possible performance reference compounds (PRCs). The accumulation phase was curvilinear for almost all molecules; so, we obtained the duration of optimal linear accumulation phase using t1/2 criteria. Concerning the desorption experiments, 5 compounds showed a good potential as PRC; they enable to decrease the effect of variable environmental conditions, so they can be used to obtain more reliable TWAC in situ. At last, we checked isotropic exchange for these molecules comparing the exchange constant ke in accumulation and desorption experiments