Person: Junek, Ralf
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Veröffentlichung Laboratory analysis of cyanobacterial toxins and bioassays(2021) Lawton, Linda A.; Junek, Ralf; Metcalf, James S.; Žegura, BojanaCyanobacterial toxins or cyanotoxins are a diverse group of compounds with differing chemistries; hence, a single analytical method can rarely be used to evaluate all potential compounds. Toxicity bioassays have been adapted to assess the toxicity of cyanobacterial samples. The most common of these assays is the Enzyme-Linked Immunosorbent Assay kit using antibodies raised to specific cyanotoxins. Testing with bioassays is expected to show whether the sample contains toxic substances and how toxic these substances may potentially be. Laboratory staff handling samples potentially containing toxic cyanobacteria and cyanobacterial toxins is potentially exposed to health hazards, and appropriate protective measures need to be implemented. Following a sampling trip, the samples arriving in the laboratory need to be processed further for analysis or storage. Three aspects are important for sample handling and storage: safety, sample processing to ensure stability and traceability. Quelle: Chorus, I., & Welker, M. (Eds.). (2021). Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management (2nd ed.). CRC Press. https://doi.org/10.1201/9781003081449, page 747Veröffentlichung Gesundheitsbezogene Optimierung der Aufbereitung von Badebeckenwasser(2016) Grummt, Tamara; Schmalz, Christina; Junek, Ralf; Waldmann, PetraVeröffentlichung Assessing the protection gap for mobile and persistent chemicals during advanced water treatment - a study in a drinking water production and wastewater treatment plant(2022) Gollong, Grete; Neuwald, Isabelle; Junek, Ralf; Kuckelkorn, JochenPersistent and mobile (PM) chemicals spread quickly in the water cycle and can reach drinking water. If these chemicals are also toxic (PMT) they may pose a threat to the aquatic environment and drinking water alike, and thus measures to prevent their spread are necessary. In this study, nontarget screening and cell-based toxicity tests after a polarity-based fractionation into polar and non-polar chemicals are utilized to assess and compare the effectiveness of ozonation and filtration through activated carbon in a wastewater treatment and drinking water production plant. Especially during wastewater treatment, differences in removal efficiency were evident. While median areas of non-polar features were reduced by a factor of 270, median areas for polar chemicals were only reduced by a factor of 4. Polar features showed significantly higher areas than their non-polar counterparts in wastewater treatment plant effluent and finished drinking water, implying a protection gap for these chemicals. Toxicity tests revealed higher initial toxicities (especially oxidative stress and estrogenic activity) for the non-polar fraction, but also showed a more pronounced decrease during treatment. Generally, the toxicity of the effluent was low for both fractions. Combined, these results imply a less effective removal but also a lower toxicity of polar chemicals. The behaviour of features during advanced waste and drinking water treatment was used to classify them as either PM chemicals or mobile transformation products (M-TPs). A suspect screening of the 476 highest intensity PM chemicals and M-TPs in 57 environmental and tap water samples showed high frequencies of detection (median >80%), which indicates the wide distribution of these chemicals in the aquatic environment and thus supports the chosen classification approach and the more generally applicability of obtained insights. © 2022 ElsevierVeröffentlichung Toxic Cyanobacteria in Water(IWA Publishing, 2021) Fastner, Jutta; Junek, Ralf; Klitzke, Sondra; Chorus, Ingrid; Welker, Martin; World Health Organization; Institut für Wasser-, Boden- und Lufthygiene (Berlin)Veröffentlichung Pool water disinfection by ozone-bromine treatment: Assessing the disinfectant efficacy and the occurrence and in vitro toxicity of brominated disinfection by-products(2021) El-Athman, Fatima; Junek, Ralf; Kämpfe, Alexander David; Mahringer, Daniel; Selinka, Hans-Christoph; Zehlike, Lisa; Grunert, AndreasPool water is continuously circulated and reused after an extensive treatment including disinfection by chlorination, ozonation or UV treatment. In Germany, these methods are regulated by DIN standard 19643. Recently, the DIN standard has been extended by a new disinfection method using hypobromous acid as disinfectant formed by introducing ozone into water with naturally or artificially high bromide content during water treatment. In this study, we tested the disinfection efficacy of the ozone-bromine treatment in comparison to hypochlorous acid in a flow-through test rig using the bacterial indicator strains Escherichia coli, Enterococcus faecium, Pseudomonas aeruginosa, and Staphylococcus aureus and the viral indicators phage MS2 and phage PRD1. Furthermore, the formation of disinfection by-products and their potential toxic effects were investigated in eight pool water samples using different disinfection methods including the ozone-bromine treatment. Our results show that the efficacy of hypobromous acid, depending on its concentration and the tested organism, is comparable to that of hypochlorous acid. Hypobromous acid was effective against five of six tested indicator organisms. However, using Pseudomonas aeruginosa and drinking water as test water, both tested disinfectants (0.6 mg L-1 as Cl2 hypobromous acid as well as 0.3 mg L-1 as Cl2 hypochlorous acid) did not achieve a reduction of four log10 levels within 30 s, as required by DIN 19643. The formation of brominated disinfection by-products depends primarily on the bromide concentration of the filling water, with the treatment method having a smaller effect. The eight pool water samples did not show critical values in vitro for acute cytotoxicity or genotoxicity in the applied assays. In real pool water samples, the acute toxicological potential was not higher than for conventional disinfection methods. However, for a final assessment of toxicity, all single substance toxicities of known DBPs present in pool water treated by the ozone-bromine treatment have to be analyzed additionally. © 2021 The Authors