Entry of biocides and their transformation products into groundwater via urban stormwater infiltration systems. (1st November 2018)

• Record Type: Journal Article
• Authors: Hensen, Birte; Lange, Jens; Jackisch, Nicole; Zieger, Franziska; Olsson, Oliver; Kümmerer, Klaus
• Is Part Of: Water research. Volume 144(2018)
• Page Start: 413
• Page End: 423
• Publication Date: 2018-11-01
• Subjects: Leaching -- Facade coatings -- Qualitative TP-screening -- Stormwater events -- Groundwater contamination; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2018.07.046
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Biocides are, inter alia, applied as preservatives on facades to prevent the growth of microorganisms. Their incomplete mineralization results in new compounds, so-called transformation products (TPs). Rain causes that both applied biocides and their TPs leach from facades with stormwater into the urban aquatic environment. This study is the first to investigate the introduction of the biocides Diuron, Terbutryn, and Octylisothiazolinone (OIT) and their TPs into the groundwater via urban stormwater infiltration systems. In this study, the TPs of these biocides were created by laboratory photolysis and elucidated using LC-HRMS. The results were then used to analyze TPs by LC-MS/MS in stormwater and groundwater samples, which were taken from an urban swale-trench system and from groundwater wells upgradient and downgradient of the infiltration system. A sprinkling experiment was conducted to evaluate facades as a contamination source. Biodegradation tests were conducted to determine bio-persistence of biocides and their TPs. Fourteen TPs were identified under laboratory photolysis. TP-186, TP-210, and TP-256 of Terbutryn were hitherto unknown. Nine TPs were qualitatively detected in environmental water samples. Parent compounds, TP-219 of Diuron and TP-212, TP-214, and TP-226 of Terbutryn were detected at a maximum concentration of 140 ng L −1 during stormwater events. Concentrations in groundwater were considerably below German drinking water limits, but were higher in groundwater samples downgradient from the investigated swale-trench system than in those collected upgradient. Neither the biocides nor most of their TPs were readily biodegradable under simulated surface water conditions. The results show that entry of biocides and their TPs into groundwater is caused by infiltration of urban stormwater. Graphical abstract: Image 1 Highlights: First-time detection of transformation products (TPs) of facade biocides in groundwater. Two of three hitherto unknown TPs of Terbutryn were detected in environmental samples. Photolysis provided analytical data for a qualitative screening of TPs in environmental samples. Demonstration of entry of biocides and their TPs from building facades into groundwater. Investigated swale-trench system causes groundwater contamination by biocides and their TPs.