Work

Two-Year Water Quality Monitoring of Drinking Water Treatment Plants in Biscay (Basque Country)

Year: 2026

Type: article

Abstract: Drinking water is one of the many potential routes of human exposure to environmental contaminants, as it often originates from anthropogenically impacted sources. This two-year study monitored contaminants of emerging concern (CECs) in five drinking water treatment plants (DWTPs) across the Basque Country. A complementary analytical approach combining target analysis and non-target screening (NTS) was employed to assess the presence of CECs in both non-treated and treated waters. DWTPs sourcing water from surface waters exhibited the highest number of CECs, with compounds such as metformin and didecyldimethylammonium (DDAC) frequently detected (> 30%). The presence of CECs in treated water overall suggests that the implemented treatment technologies are not fully effective in removing them. The detected, non-eliminated contaminants were prioritised based on a human health risk assessment (HHRA) and several compounds, including norgestimate, tris(2-butoxyethyl)phosphate (TBOEP), and DDAC, were identified as posing the highest potential risk to human health. In addition, an effect-based methodology (EBM) with bioassays targeting cytotoxicity and mutagenicity was applied to provide a more comprehensive evaluation of mixture effects. No detectable biological activity was observed in any of the samples, suggesting a potentially low risk for human health regarding the evaluated endpoints. The divergence between concentration-based prioritisation and bioassay results suggests the need to expand experimental testing across a broader range of biological endpoints, such as endocrine disruption, which may not be captured by the applied assays.

Source: Exposure and Health

DOI: 10.1007/s12403-026-00795-8