Assessment of source and treated water quality in seven drinking water treatment plants by in vitro bioassays – Oxidative stress and antiandrogenic effects after artificial infiltration

Johan Lundqvist,Geeta Mandava,Andrew Holmes,Anna Kjerstine Rosenmai,Agneta Oskarsson,Anders Johannisson,Rikard Tröger

doi:10.1016/j.scitotenv.2020.144001

Abstract

Drinking water quality and treatment efficacy was investigated in seven drinking water treatment plants (DWTPs), using water from the river Göta Älv, which also is a recipient of treated sewage water. A panel of cell-based bioassays was used, including measurements of receptor activity of aryl hydrocarbon (AhR), estrogen (ER), androgen (AR), peroxisome proliferator-activated receptor alpha (PPARα) as well as induction of oxidative stress (Nrf2) and micronuclei formation. Grab water samples were concentrated by solid phase extraction (SPE) and water samples were analyzed at a relative enrichment factor of 50. High activities of AhR, ER and AR antagonism were present in WWTP outlets along the river. Inlet water from the river exhibited AhR and AR antagonistic activities. AhR activity was removed by DWTPs using granulated activated carbon (GAC) and artificial infiltration. AR antagonistic activity was removed by the treatment plants, except the artificial infiltration plant, which actually increased the activity. Furthermore, treated drinking water from the DWTP using artificial infiltration exhibited high Nrf2 activity, which was not found in any of the other water samples. Nrf2 activity was found in water from eight of the 13 abstraction wells, collecting water from the artificial infiltration. No genotoxic activity was detected at non-cytotoxic concentrations. No Nrf2 or AR antagonistic activities were detected in the inlet or outlet water after the DWTP had been replaced by a new plant, using membrane ultrafiltration and GAC. Neither target chemical analysis, nor chemical analysis according to the drinking water regulation, detected any presence of chemicals, which could be responsible of the prominent effects on oxidative stress and AR antagonistic activity in the drinking water samples. Thus, bioanalysis is a useful tool for detection of unknown hazards in drinking water and for assessment of drinking water treatments.

Highlights

Access to safe drinking water is essential to health (WHO, 2011)
The test water samples did not affect cell viability in HepG2 and VM7Luc4E2 cells, with the threshold set at 80%, while we found a reduced viability in AR-EcoScreen cells after treatment with inlet water samples from DWTPs 2, 3 and 4, outlet water sample from DWTP4, and in surface water from SW1 (Fig. S2)
The samples causing decreased cell viability at 50 relative enrichment factor (REF) were tested in dilutions to determine the highest non-toxic concentrations, which were found to be 25 REF for inlet water samples from DWTPs 2, 3 and 4, and 12.5 REF for DWTP4 outlet water sample and for SW1

Summary

Introduction

Access to safe drinking water is essential to health (WHO, 2011). Chemical contamination of the environment may be a serious threat, especially when surface water is used as a source for drinking water. Detection and removal of contaminating chemicals in the drinking water treatment plants is important and a great challenge. Chemical analyses do not give information on the potential toxic effects of the complex mixture of natural and anthropogenic chemicals, which may be present in drinking water. Effect-based methods have been increasingly applied in water quality monitoring, especially of surface and wastewater, to detect biological activities relevant to adverse health effects (Altenburger et al, 2019; Brack et al, 2019; Dopp et al, 2019; Escher et al, 2018; Konig et al, 2017)

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