Detection, identification and quantification of EPs and their transformation products in the various environmental
compartments is essential for gaining knowledge on their occurrence and fate.This is highly challenging for several
reasons : the number of currently known potential EPs (and relevant transformation products) is very high(>700 in
Europe).Their relevance changes over time due to changes in production,use and disposal of (agro) chemicals, and
new information on their occurrence, fate and hazards .Certain EPs o.a.hormones, pyrethroids and certain
organophosphorus pesticides (Von der Ohe et al. ,2011; RIVM, 2012) affect the aquatic environment at extremely
low concentrations and need analytical methods with correspondingly low detection limits. Not all EPs/TPs are
known at the moment of sampling and analysis.