# Multi-Residue Determination and Risk Assessment of EU-Relevant Pharmaceuticals, Pesticides, and UV-Filters in Drinking Water

## TL;DR

This study developed a sensitive method to detect micropollutants in drinking water and found low levels that do not pose significant health risks.

## Contribution

A highly sensitive SPE-UHPLC-MS/MS method was optimized for detecting EU-relevant micropollutants in drinking water.

## Key findings

- The method detected up to 3 micropollutants per sample at concentrations between 0.28 and 98.8 ng L−1.
- Four out of 23 target compounds were detected, with hazard quotients below 0.1, indicating low health risk.
- Some compounds exceeded calibration limits, suggesting the need for improved monitoring.

## Abstract

Scientific concern regarding the widespread occurrence of micropollutants (MPs) in aquatic environments has been growing. Background/Objectives: Since conventional wastewater and drinking water (DW) treatment plants are generally unable to completely remove MPs, their presence in DW may occur, potentially posing adverse effects on public health. Highly sensitive analytical methods are crucial, as MPs may occur at very low concentrations in DW, usually at ng L−1 levels. Methods: An offline solid-phase extraction ultra-high performance liquid-chromatography coupled to tandem mass-spectrometry (SPE-UHPLC-MS/MS) method was optimized and validated for the determination of 23 MPs in DW, including 12 pharmaceuticals, 9 pesticides, and 2 UV-filters, listed in the 2 most recent European Union (EU) Decisions (2022/1307 and 2025/439) for surface water monitoring, and in the revised EU Urban Wastewater Treatment Directive (2024/3019). The validated method was applied to 50 DW samples collected across Portugal. Results: The optimized SPE-UHPLC-MS/MS method showed high analytical sensitivity, achieving method detection limits below 1.50 ng L−1. Up to 3 MPs were detected per sample, with quantifiable concentrations of each ranging from 0.28 to 98.8 ng L−1. However, benzotriazole and dimoxystrobin exceeded the upper limits of their calibration curves (i.e., concentrations higher than 133 and 117 ng L−1, respectively) in one and 3 of the collected samples, respectively. Considering all analyzed samples, 4 (fluconazole, irbesartan, dimoxystrobin, and benzotriazole) of the 23 target compounds were detected. Hazard quotient values for all detected MPs were well below 0.1. Conclusions: The validated SPE-UHPLC-MS/MS method is suitable for the sensitive determination of MPs in DW. Some MPs were detected, with concentrations indicating no expected human health risks under the conditions evaluated. Further monitoring campaigns should be conducted in the future, with compounds exceeding the limits of the calibration curves requiring special attention.