In-situ calibration of POCIS for the sampling of polar pesticides and metabolites in surface water.

Over the past years, passive sampling devices have been successfully used for the monitoring of various pollutants in water. The present work studied the uptake kinetics in surface water of ten polar pesticides and metabolites, using pharmaceutical POCIS samplers. The aim was to determine sampling rates from in-situ calibration and to compare results with those obtained earlier under laboratory conditions, with the final objective of assessing the impact of environmental conditions on POCIS field performance. Field results showed a low efficiency of POCIS uptake capacity for moderately polar compounds, such as propiconazole (log Kow=3.72) and tebuconazole (log Kow=3.7), that were present in the aqueous phase at very low levels. The in-situ sampling rates obtained in this study ranged from 169 to 479 mL g(-1)day(-1) and differ by a factor of 3-7.5 from Rs determined under laboratory conditions.