HPLC-UV screening project

Monitoring the quality of surface water

About 40% of the drinking water in the Netherlands comes from surface water. More treatment is needed to use surface water as drinking water than in the case of groundwater because more contaminants, and higher concentrations of those contaminants, are present in surface water. Concentrations of contaminants are sometimes so high that there are health risks, requiring a temporary suspension of the use of the drinking water source in question for drinking water production. Rijkswaterstaat monitors the water quality of the Rhine and Meuse rivers 24/7 throughout the Netherlands. In Lobith and Eijsden (on the country’s borders), this work is done with techniques such as HPLC-UV. The drinking water utilities and their laboratories also monitor Lake IJssel  and the rivers at different locations using the same technology. The role of HPLC-UV in active online water-quality monitoring is a form of non-target screening and its robust and relatively straightforward design means is that it complements other more advanced analytical techniques such as HRMS (high-resolution mass spectrometry).

Different approaches combined in a single project

In the HPLC-UV screening project, KWR, Evides, WML, Rijkswaterstaat and Aqualab Zuid have already been working together for more than fifteen years to keep the HPLC-UV knowledge and technology up to standard and to establish a picture of new, emerging substances early. The heart of the project involves joint efforts to achieve extensive harmonisation of the analysis method used and the processing of the monitoring data (UV spectra). The harmonised approach and the HPLC-UV2R spectrum database developed by KWR are used by Rijkswaterstaat and Aqualab Zuid for detection and data exchange for known and as yet unidentified unknown compounds, allowing very reliable linkage and comparison of the monitoring data. The collaborative UV spectrum library currently includes the spectra of more than 170 known substances and new substances are added to it every year. The comparability, exchangeability and applicability of the HPLC-UV method is tested periodically in a proficiency test. Until 2022, proficiency testing took place on an annual basis. Currently, it is done every two years because the results demonstrated that the monitoring methods are used at all the participating laboratories is robust and well harmonised. In addition, the substances found in surface water by Rijkswaterstaat and Aqualab Zuid are assessed annually by KWR to determine how often they have been found, in which concentrations and at which locations, and – when this information is available – treatment efficiency at drinking water treatment plants. On this basis, known and unknown compounds are prioritised and important trends with respect to new, emerging substances are identified.

Combined efforts strengthen knowledge

The combined efforts in the HPLC-UV screening project provide insight in the presence of substances and allow for the early identification of new, emerging substances. We can identify more and more substances after they have been measured with the proven, robust and harmonised HPLC-UV method. We monitor ongoing developments in the science relating to data by continually optimising our solutions for data interpretation and representation. Sharing this knowledge with each other puts the water sector in a position where it can respond effectively to trends and potential threats, and it keeps the knowledge and technology required to deliver the requisite insights up to standard.