Non-targeted screening of organic micropollutants in drinking water: Evidence of contamination from purification systems and plastic materials

Concerns over organic micropollutants (MPs) in drinking water are growing due to their persistence in aquatic environments and the limitations of conventional tap water treatment methods. Alternative pathways, including water purifiers, cause potential human exposure to MPs through drinking water. This study investigates potential human exposure to MPs through drinking water by analyzing five sample sets: (1) water from 12 campus purifiers, (2) water from tap and 2 purifiers over 12 weeks, (3) purified water from 21 public buildings, (4) bottled water from sources across Korea, and (5) sonicated water extract of purifier-filter-elements. All samples were pretreated via solid-phase extraction and then analyzed to identify MPs through suspect and nontarget screening using liquid chromatography high-resolution mass spectrometry. A total of 41 MPs were tentatively identified through MS/MS spectral pattern diagnosis, including plasticizers, plastic derivatives, organophosphorus flame retardants (OPFRs), pesticides, and pharmaceuticals. Among these, 24 MPs were confirmed with standards, 6 were quantified with standards, and 4 were semi-quantified without standards. Notably, four OPFRs were found in purified water (up to 3900 ng/L) and tap water (up to 130 ng/L). Additionally, plastic-derived PA6 oligomers were detected in purified water, with concentrations reaching 5300 ng/L. The presence of OPFRs and plastic-derived oligomers in household purified water was suggested to be linked to the water’s contact with plastic tanks and pipes, as well as the use of fiber wipers during purifier cleaning. The findings suggest the potential utility of non-targeted monitoring of drinking water and support its use to inform future targeted monitoring efforts.