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Published on: December 4, 2016
Assessing drinking water treatment efficiency using passive sampling and cell-based bioassays
Martin Ezechiáš1, Michaela Hegrová Helusová1,2, Gabriela Horáková1,2
1Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia.
Frontiers in Toxicology
|May 8, 2026
Summary
This study used passive sampling and bioassays to assess drinking water treatment effectiveness. While estrogenic activity was removed, some AhR-active substances persisted, indicating incomplete removal of certain contaminants.
Area of Science:
- Environmental Chemistry
- Toxicology
- Water Quality Analysis
Background:
- Drinking water treatment plants (DWTPs) aim for public health protection, but residual contaminants can cause biological effects missed by standard chemical monitoring.
- Assessing biological activity of contaminants is crucial for understanding treatment efficacy beyond chemical analysis.
Purpose of the Study:
- To evaluate residual biological activity in raw and treated water from Czech DWTPs using passive sampling and in vitro bioassays.
- To assess the efficiency of drinking water treatment processes in removing biologically active substances.
Main Methods:
- Combined Polar Organic Chemical Integrative Samplers (POCIS) with in vitro bioassays (transcriptional responses in RTL-W1 cells, yeast bioassays for estrogenic/progestogenic activity).
- Deployed POCIS in raw and treated water to collect contaminant mixtures for analysis.
- Evaluated specific biomarkers including CYP1A, GST, HSP, and Nrf2 gene expression.
Main Results:
- CYP1A gene expression indicated the presence of AhR-active substances in raw water, with incomplete removal during treatment in some cases.
- Weak responses in phase II detoxification and stress-related genes suggested receptor-mediated effects rather than general toxicity.
- Estrogenic activity was detected in all raw waters but not in treated waters, showing efficient removal.
Conclusions:
- Effect-directed analysis using passive sampling and bioassays is suitable for assessing drinking water treatment efficiency.
- This approach can identify treatment-resistant bioactivities missed by conventional chemical monitoring.
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