Passive sampling has certainly a lot to offer for monitoring emerging pollutants in water, but it also has limitations. Passive sampling is rather well established for non-polar organic chemicals, where they can be used in the kinetic regime to measure time weighted average concentrations. Such kinetic passive sampling will be rather easy to apply to some emerging pollutants, but not to others. It really depends on the physicochemical properties of the pollutants. A specific challenge in this area has been to apply polar performance reference compounds correctly, which are required for a solid calibration of kinetic passive sampling methods. Based on the recent literature this seems to remain a challenge.

Passive sampling of organic pollutants in water is rather well established. Therefore, have a look at e.g. the Web of Science and search for "passive sampling" and "your specific emerging pollutants".

One additional aspect is that passive sampling generally measures freely dissolved concentrations, which are very relevant in terms of exposure and fate. However, most regulatory thresholds are set on the basis of total concentration (concentration of free and bound form of analyte). Therefore, there is sometimes a mismatch between the regulatory endpoints and the measurement endpoints of the passive sampling technqiues.

Finally, there are many types of passive sampling methods each with their specific advantages and limitations. Personally, I am working with equilibrium sampling methods (equlibrium sampling devices), which are very simple though powerfull analytical techniques for hydrophobic organic pollutants (down to fg/L), and also applicable in complex matrices such as sediment and soil.