Occurrence and removal of organic micropollutants in drinking water : Analytical approaches for wide-scope screening of contaminants of emerging concern

With the rapidly expanding global population, demand for clean drinking water is increasing. However, the widespread use of synthetic chemicals makes it challenging to produce safe and clean drinking water. A wide range of common chemicals can pose problems for drinking water producers, particularly pharmaceuticals, pesticides, per- and polyfluoroalkyl substances (PFASs), drugs, flame retardants, food additives, personal care products and industrial chemicals. Conventional drinking water treatment is not designed to effectively remove all these compound groups, and many organic compounds may slip through treatment barriers due to their high polarity and mobility. This thesis examined the removal efficiencies of unwanted substances at drinking water treatment plants (DWTPs) employing various treatment strategies, and sought to develop broad and accurate analytical techniques to measure a wide range of micropollutants. The aim was to improve understanding of the occurrence and removal of contaminants of emerging concern (CECs) in raw, process and drinking water in Sweden and internationally. A broad target screening method based on large volume extraction and high- resolution mass spectrometry (HRMS) was developed to investigate the status of Sweden’s most important water source and one major DWTP. The method was then refined using a semi-automated extraction method and a broader analytical method, which was used in a field study of several drinking water treatment plants along Sweden’s second most important water source. The influence of operational age on the effectiveness of granular activated carbon (GAC) filters in removing CECs was studied in one full-scale DWTP. To extend the scope of the analytical method further, a tool for creating relevant suspect lists was developed. A suspect list created using this tool and an extensive target list were used in a large screening study of raw water and drinking water samples from 13 DWTPs located in 11 countries in Europe and Asia. The novel findings in this thesis on the current status of CECs in raw water and drinking water, and on the suitability of current treatment techniques for efficient removal of CECs in drinking water production, can help improve drinking water quality worldwide.