  A comprehensive approach to protect river water quality is needed within the
European Water Framework Directive. Non-target screening of a complete chemical
fingerprint of the aquatic ecosystem is essential, to identify chemicals of
emerging concern and to reveal their suspicious dynamic patterns in river
water. This requires a new combination of two measurement paradigms: the path
of potential pollution should be traced through the river network, while there
may be many compounds that make up this chemical composition - both known and
unknown. Dedicated data processing of ongoing GC-MS measurements at 9 sites
along the Rhine using PARAFAC2 for non-target screening, combined with
spatiotemporal modelling of these sites within the river network using path
modelling (Process PLS), provided a new integrated approach to track chemicals
through the Rhine catchment, and tentatively identify known and as-yet unknown
potential pollutants based on non-target screening and spatiotemporal
behaviour.
