Integrating chemical analysis and bioanalysis to evaluate the contribution of wastewater effluent on the micropollutant burden in small streams.
Surface waters can contain a range of micropollutants from point sources, such as wastewater effluent, and diffuse sources, such as agriculture. Characterizing the source of micropollutants is important for reducing their burden and thus mitigating adverse effects on aquatic ecosystems. In this study, chemical analysis and bioanalysis were applied to assess the micropollutant burden during low flow conditions upstream and downstream of three wastewater treatment plants (WWTPs) discharging into small streams in the Swiss Plateau. The upstream sites had no input of wastewater effluent, allowing a direct comparison of the observed effects with and without the contribution of wastewater. Four hundred and five chemicals were analyzed, while the applied bioassays included activation of the aryl hydrocarbon receptor, activation of the androgen receptor, activation of the estrogen receptor, photosystem II inhibition, acetylcholinesterase inhibition and adaptive stress responses for oxidative stress, genotoxicity and inflammation, as well as assays indicative of estrogenic activity and developmental toxicity in zebrafish embryos. Chemical analysis and bioanalysis showed higher chemical concentrations and effects for the effluent samples, with the lowest chemical concentrations and effects in most assays for the upstream sites. Mixture toxicity modeling was applied to assess the contribution of detected chemicals to the observed effect. For most bioassays, very little of the observed effects could be explained by the detected chemicals, with the exception of photosystem II inhibition, where herbicides explained the majority of the effect. This emphasizes the importance of combining bioanalysis with chemical analysis to provide a more complete picture of the micropollutant burden. While the wastewater effluents had a significant contribution to micropollutant burden downstream, both chemical analysis and bioanalysis showed a relevant contribution of diffuse sources from upstream during low flow conditions, suggesting that upgrading WWTPs will not completely reduce the micropollutant burden, but further source control measures will be required.
Australian Rivers Institute, Griffith School of Environment, Griffith University, Southport, QLD 4222, Australia; The University of Queensland, National Research Centre for Environmental Toxicology (Entox), Brisbane, QLD 4108, Australia.
Peta A
PA
Neale
Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, 8092 Zürich, Switzerland.
Nicole A
NA
Munz
Institut National de l'Environnement Industriel et des Risques INERIS, Unité d'Ecotoxicologie, 60550 Verneuil-en-Halatte, France.
Selim
S
Aїt-Aїssa
UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany.
Rolf
R
Altenburger
Institut National de l'Environnement Industriel et des Risques INERIS, Unité d'Ecotoxicologie, 60550 Verneuil-en-Halatte, France.
François
F
Brion
UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany.
Wibke
W
Busch
Australian Rivers Institute, Griffith School of Environment, Griffith University, Southport, QLD 4222, Australia; The University of Queensland, National Research Centre for Environmental Toxicology (Entox), Brisbane, QLD 4108, Australia; UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany; Eberhard Karls University Tübingen, Environmental Toxicology, Center for Applied Geosciences, 72074 Tübingen, Germany. Electronic address: beate.escher@ufz.de.
Beate I
BI
Escher
Masaryk University, Research Centre for Toxic Compounds in the Environment (RECETOX), Kamenice 753/5, 62500 Brno, Czech Republic.
Klára
K
Hilscherová
Swiss Centre for Applied Ecotoxicology Eawag-EPFL, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland.
Cornelia
C
Kienle
Masaryk University, Research Centre for Toxic Compounds in the Environment (RECETOX), Kamenice 753/5, 62500 Brno, Czech Republic.
Jiří
J
Novák
Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, 52074 Aachen, Germany.
Thomas-Benjamin
TB
Seiler
Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, 52074 Aachen, Germany.
Ying
Y
Shao
Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland.
Christian
C
Stamm
Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, 8092 Zürich, Switzerland.
Juliane
J
Hollender
Bioassays; Chemical analysis; Micropollutant; Mixture modeling; Surface water; Wastewater