Combination of effect-based monitoring and targeted screening of (drinking) water quality I: multivariate pattern analysis of bioassay survey and screening data

This study applied in vitro bioassays and high resolution targeted screening in the (drinking) water cycle to investigate chemicals of emerging concern. The presence of activity for 10 bioassay endpoints (endocrine (ant)agonistic and reactive modes of action) was assessed in waste water treatment plant (WWTP) effluent, surface water (SW), process water and drinking water (DW) of 4 DW companies in the Rhine and Meuse catchments. Eight of the ten biological activities were detected in the samples. Most of them were completely removed during the DW production. High resolution targeted screening detected significantly more contaminants with significantly higher peak areas (indicative for concentrations) at locations in the Rhine than in the Meuse. A principal component analysis enabled separate clustering of locations in the Rhine versus locations in the Meuse catchment. Most DW samples clustered far away from the SW they were produced from. This indicates that water treatment technologies applied to the SW affected the water quality of DW to a larger extent than the SW sources themselves. Hierarchical cluster analysis (HCA) showed that agricultural compounds, natural compounds, steroids and per- and polyfluoroalkyl substances (PFAS) contributed the most to the clustering of samples from the Meuse locations, whereas pharmaceuticals were the main application group contributing to the Rhine cluster. It was found that the clustering in HCA, although very capable of pinpointing patterns in contaminating compounds, did not directly refer to the drivers of the observed bioassay activities, thereby underlining the need for EDA for this purpose. An accompanying article reports the Effect-Directed Analysis (EDA) that was performed consequently to identify the compounds that caused the bioassay activities.