This work set out the calibration of pharmaceutical POCIS with 20 herbicides. The calibration revealed linear and integrative uptakes of several herbicides for 21 days but some compounds like sulcotrione, mesotrione, atrazine-desisopropyl (DIA) and atrazine-desethyl (DEA) exhibited curvilinear uptakes. We assumed first-order isotropic exchanges for these polar compounds and we estimated the elimination rate constant of the DIA. For this purpose, we spiked the sorbent contained within pharmaceutical POCIS with DIA, simazine and isoproturon and we studied their dissipations for 10 days. For DIA, the exchanges appeared to be isotropic and the dissipation was correctly discribed by a first-order monophasic kinetic law.

Further microcosm experiments were performed with river freshwater and strong turbulences (from 10 to 20 times more elevated than calibration flow velocities). The POCIS containing sorbents fortified with DIA were exposed during 9 days. The waters were spiked with terbuthylazine-desethyl (DET), terbuthylazine, isoproturon and acetochlor at either moderate and constant concentrations or 3-day peak concentrations. The real concentrations determined with repetitive grab sampling and time-weighted average concentrations estimated from POCIS were compared. The results showed that a peak of pollution is correctly integrated by the POCIS but the TWA concentrations can be overestimated. However, the use of DIA as a performance reference compound (PRC) provided a good correction of the turbulence and biofouling effects. In fact, the TWA concentrations estimated with the PRC dissipation were closer to the real values. As for SPMDs, multiple PRCs are probably needed to cover the wide range of environmental exposure conditions and further works will concern the dissipation of other polar organic chemicals from pharmaceutical POCIS.