Emerging priority substances in the aquatic environment: a role for passive sampling in supporting WFD monitoring and compliance
Passive sampling (PS) is proving to be a valuable tool for the monitoring of priority substances in water, sediment and biota. PS techniques generally enable much greater sensitivity than can be achieved by “traditional” spot-sampling, potentially improving detection capabilities by orders of magnitude. Passive sampling is generally applicable to a wide variety of compounds including non-polar organic substances (e.g. PAHs, PCBs and PBDEs), polar compounds (e.g. pharmaceuticals and certain pesticides), trace metals, metalloids and radionuclides and organo-metallic compounds (e.g. TBT). A list of proposed emerging compounds was introduced to European legislation (in addition to the Water Framework Directive (WFD) 2000/60/EC) in 2013. This new EU Directive (2013/39/EC) has added some additional priority substances to the existing WFD Priority Substance list. Investigation into the utility of passive sampling in the monitoring of these compounds is necessary to show the potential value of this technique in supporting the monitoring requirements under the WFD. This review deals with the challenges associated with the use of passive sampling in a legislative context, and for routine monitoring of emerging contaminants such as pharmaceuticals, steroids and pesticides. There is still much work to be done before passive sampling methodologies can emerge as a complementary technique for water monitoring.