Ecotoxicological Assessment of Immersion Samples from Facade Render Containing Free or Encapsulated Biocides

Abstract

To protect house facades from fouling by microorganisms, biocides can be added to a render or paint before it is applied. During driving rain events, these biocides gradually leach out and have the potential to pollute soil or aquatic ecosystems. We studied the leaching behavior of biocides and toxicity of leachates from renders with either free or encapsulated biocides. Both render types contained equal amounts of terbutryn, 2-octyl-3(2H)-isothiazolinone (OIT), and 4,5-dichloro-2-n-octyl-4-isothiazolino-3-one (DCOIT). Nine leachate samples were generated over 9 immersion cycles according to a European standard, and biocides were quantified. The first and ninth leachate samples were tested using bioassays with algae, bacteria, and water fleas, the first sample was also tested with earthworms and springtails. Encapsulation reduced leaching of terbutryn, OIT, and DCOIT by 4-, 17-, and 27-fold. For aquatic organisms, the toxicity of water from render containing encapsulated biocides was always lower than that of render with free biocides. Furthermore, toxicity decreased by 4- to 5-fold over the 9 immersion cycles. Inhibition of photosynthesis was the most sensitive endpoint, followed by algal growth rate, bacterial bioluminescence, and water flea reproduction. Toxicity to algae was due to terbutryn and toxicity to bacteria was due to OIT. None of the samples affected soil organisms. Results demonstrate that combining standardized leaching tests with standardized bioassays is a promising approach to evaluate the ecotoxicity of biocides that leach from facade renders. Environ Toxicol Chem 2018;37:2246-2256. © 2018 SETAC.

Determination of 18 Biocides in Both the Dissolved and Particulate Fractions of Urban and Surface Waters by HPLC-MS/MS

“…In recent years, biocidal substances in the aquatic environment have received an increasing attention because of (i) their many uses especially in urban areas (Bester et al 2008;Bollmann et al 2014b;Paijens et al 2020;Wieck et al 2018), (ii) their transfer into the aquatic environment via wastewater or stormwater discharges (Bollmann et al 2014a;Burkhardt et al 2011;Juksu et al 2019;Wicke et al 2015), and (iii) their negative effect on aquatic organisms (Mohr et al 2008;Vermeirssen et al 2018). Indeed, biocides are toxic and may cause long-term adverse effects to aquatic ecosystems even at low concentrations, such as endocrine disruption in zebrafish larvae (Jiang et al, 2015) or behavioural disturbance in zebrafish embryos (Andrade et al, 2016).…”

Biocide emissions from building materials during wet weather: identification of substances, mechanism of release and transfer to the aquatic environment

“…Only scarce studies assess the toxicity of the leachates though this would be a relevant tool for assessing potential environmental impact (Bandow et al 2018). For instance, Vermeirssen et al (2018) conducted ecotoxicity test on leachates and demonstrated that combining standardized leaching tests with standardized bioassays is a valuable tool to assess the environmental risk of biocide releases from façade renders and to rank the different materials according to potential ecotoxicity.…”

Current and future chemical treatments to fight biodeterioration of outdoor building materials and associated biofilms: Moving away from ecotoxic and towards efficient, sustainable solutions

“…Finally, ITs are very frequently used to prevent the biodeterioration of buildings, roofs, stones, and facades. For example, ITs and especially OIT and its derivative the 4,5-dichloro-2octyl-2H-isothiazol-3-one (DCOIT, CAS: 64359-81-5) are utilized in paints that are sold to protect house facades (Vermeirssen et al, 2018), such as Lichenicida 468 (Bresciani) (Favero-Longo et al, 2017) or Algi 201 (Algimouss Pro, ITs concentration 0.45%). They can be employed alone or combined with other antifouling compounds, such as quaternary ammonium compounds (see below).…”