The Water Framework Directive (WFD) is a European Union Directive which commits all European Union Member States to make all water bodies, inclusive of marine waters up to a kilometre from shore, of good status by 2015. Since 2003 national regulations implementing the Directive have been put in place. There are 41 pollutants that were set down by the EPA as priority pollutants (Annex X of the WFD). Priority pollutants are specific pollutants that include heavy metals and specific organic chemicals. There are four main groups of priority pollutants; pesticides, metals and there compounds, polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). It is necessary to establish a monitoring system for priority pollutants that is not only cost and time effective but also simple to implement. One emerging analytical method for the monitoring of these priority pollutants is the use of passive sampling devices. Passive samplers work on the basis of analyte diffusion into a membrane that is selective to their enrichment. This thesis outlines the development of analytical methodology for the analysis of pesticides in aqueous solutions and also the development and screening of novel passive sampling materials. The novel passive sampling polymer devices are made using poly(vinylchloride) (PVC) and contains a plasticiser to aid the enrichment of analytes. The passive sampling devices are exposed to aqueous systems spiked with priority pollutants for selected time periods. The analytes of interest are extracted from the passive samplers and the extracts are analysed using gas chromatography coupled with mass spectrometry (GC-MS).