Bioanalytical tools for the evaluation of organic micropollutants during sewage treatment, water recycling and drinking water generation

• Published in: Water research (Oxford) 2011-08, Vol.45 (14), p.4238-4247
• Main Authors: Macova, Miroslava, Toze, Simon, Hodgers, Leonie, Mueller, Jochen F., Bartkow, Michael, Escher, Beate I.
• Format: Article
• Language: English
• Subjects: Acetylcholinesterase - drug effects; Acetylcholinesterase - metabolism; Aliivibrio fischeri - drug effects; Applied sciences; Barriers; Bioassay; Bioassays; Biological Assay; chemical analysis; detection limit; Dioxins - metabolism; Drinking water; Endocrine Disruptors - metabolism; environmental health; Environmental Monitoring - methods; Escherichia coli - drug effects; Eukaryota - drug effects; Exact sciences and technology; Genotoxicity; humans; hydrologic cycle; In-vitro; Indirect potable reuse; microfiltration; Micropollutants; monitoring; neurotoxicity; oxidation; phytotoxicity; Plants (organisms); Pollution; Queensland; Receptors, Aryl Hydrocarbon - metabolism; Recycling; reverse osmosis; Sewage; sewage treatment; Toxicity; Toxicity Tests; Treatment barriers; Waste Disposal, Fluid - methods; Waste water; wastewater; Wastewater treatment; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Water Purification; Water recycling; water reuse; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2011.05.032

A bioanalytical test battery was used for monitoring organic micropollutants across an indirect potable reuse scheme testing sites across the complete water cycle from sewage to drinking water to assess the efficacy of different treatment barriers. The indirect potable reuse scheme consists of seven treatment barriers: (1) source control, (2) wastewater treatment plant, (3) microfiltration, (4) reverse osmosis, (5) advanced oxidation, (6) natural environment in a reservoir and (7) drinking water treatment plant. Bioanalytical results provide complementary information to chemical analysis on the sum of micropollutants acting together in mixtures. Six endpoints targeting the groups of chemicals with modes of toxic action of particular relevance for human and environmental health were included in the evaluation: genotoxicity, estrogenicity (endocrine disruption), neurotoxicity, phytotoxicity, dioxin-like activity and non-specific cell toxicity. The toxicity of water samples was expressed as toxic equivalent concentrations (TEQ), a measure that translates the effect of the mixtures of unknown and potentially unidentified chemicals in a water sample to the effect that a known reference compound would cause. For each bioassay a different representative reference compound was selected. In this study, the TEQ concept was applied for the first time to the umuC test indicative of genotoxicity using 4-nitroquinoline as the reference compound for direct genotoxicity and benzo[a]pyrene for genotoxicity after metabolic activation. The TEQ were observed to decrease across the seven treatment barriers in all six selected bioassays. Each bioassay showed a differentiated picture representative for a different group of chemicals and their mixture effect. The TEQ of the samples across the seven barriers were in the same order of magnitude as seen during previous individual studies in wastewater and advanced water treatment plants and reservoirs. For the first time a benchmarking was performed that allows direct comparison of different treatment technologies and covers several orders of magnitude of TEQ from highly contaminated sewage to drinking water with TEQ close or below the limit of detection. Detection limits of the bioassays were decreased in comparison to earlier studies by optimizing sample preparation and test protocols, and were comparable to or lower than the quantification limits of the routine chemical analysis, which allowed monitoring of the presence and remov