Comparison of active and passive sampling for the determination of persistent organic pollutants (POPs) in sewage treatment plants

Semipermeable membrane devices (SPMDs) and conventional active sampling methods were used for the sampling of wastewater from the wastewater treatment plant of Thessaloniki, northern Greece. The occurrence of 22 POPs was shown by both sampling methods. The most abundant compounds were heptachlor-exo-epoxide and PCBs-52; -101 and -180. Concentrations of POPs detected by active sampling and those estimated by the SPMDs matched very well in some cases, but significant mismatches were also observed. Regression analysis of the results detected by both methods showed moderate correlations. The highest uptake rate of hydrophobic compounds by SPMDs was observed for analytes with log K(OW) between 5.5 and 6.0. Our data suggest that active and passive sampling are complimentary, and that at least for the outflow of a WWTP, SPMDs could be used for the routine monitoring of compounds that are listed at the Water Framework Directive of the European Commissions.