Passive sampling combined with ecotoxicological and chemical analysis of pharmaceuticals and biocides – evaluation of three Chemcatcher™ configurations

Passive sampling is a tool to monitor the presence and concentrations of micropollutants in the aquatic environment. We investigated the duration of integrative sampling and the effects of flow rate on the performance of three configurations of the Chemcatcher – a sampler for polar organic compounds. Chemcatchers were fitted with Empore™ styrenedivinylbenzene (SDB) XC disks (XC), SDB–RPS disks (RPS) or SDB–RPS disks covered with a polyethersulfone membrane (RPS–PES). Samplers were either exposed to treated sewage effluent for 5 days at various flow rates, or at a single flow rate with overlapping exposures of 3–24 days. Chemical analysis focused on a set of pharmaceuticals and biocides and ecotoxicological analysis measured inhibition of photosystem II in algae. For compounds with log KOW > 2, both XC and RPS disks respond dynamically to higher flow rates; uptake increased up to five-fold when flow increased from 0.03 to 0.37 m s−1. At a flow rate of 0.13 m s−1 the integrative window of SDB disks approached 6 days for more hydrophobic compounds (log KOW > 3.5). The RPS–PES configuration was less affected by flow and also showed an extended integrative window (up to 24 days). The membrane causes a lag phase of up to 2.3 days which thwarts a sound interpretation of data from sampling periods of less than 10 days.