title: Most oxidative stress response in water samples comes from unknown chemicals: the need for effect-based water quality trigger values.
abstract: The induction of adaptive stress response pathways is an early and sensitive indicator of the presence of chemical and non-chemical stressors in cells. An important stress response is the Nrf-2 mediated oxidative stress response pathway where electrophilic chemicals or chemicals that cause the formation of reactive oxygen species initiate the production of antioxidants and metabolic detoxification enzymes. The AREc32 cell line is sensitive to chemicals inducing oxidative stress and has been previously applied for water quality monitoring of organic micropollutants and disinfection byproducts. Here we propose an algorithm for the derivation of effect-based water quality trigger values for this end point that is based on the combined effects of mixtures of regulated chemicals. Mixture experiments agreed with predictions by the mixture toxicity concept of concentration addition. The responses in the AREc32 and the concentrations of 269 individual chemicals were quantified in nine environmental samples, ranging from treated effluent, recycled water, stormwater to drinking water. The effects of the detected chemicals could explain less than 0.1% of the observed induction of the oxidative stress response in the sample, affirming the need to use effect-based trigger values that account for all chemicals present.
authors: National Research Centre for Environmental Toxicology (Entox), The University of Queensland, Brisbane QLD 4108, Australia. b.escher@uq.edu.au
authors: Beate I
authors: BI
authors: Escher
authors: Charlotte
authors: C
authors: van Daele
authors: Mriga
authors: M
authors: Dutt
authors: Janet Y M
authors: JY
authors: Tang
authors: Rolf
authors: R
authors: Altenburger
mesh_terms: D000465:Algorithms; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D060766:Drinking Water; D064420:Drug-Related Side Effects and Adverse Reactions; D006801:Humans; D046448:Ice Cover; D051267:NF-E2-Related Factor 2 / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects*; D010575:Pesticides / Q000592:standards / Q000633:toxicity*; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000592:standards / Q000633:toxicity*; D060753:Water Quality / Q000592:standards
chemical_list: D060766:Drinking Water; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D010575:Pesticides; D014874:Water Pollutants, Chemical