abstract
Biofouling is one of the most challenging problems for the maritime industry which has been minimized through the application of coatings containing anti-fouling (AF) biocides (e.g. Cu-based compounds; DCOIT) in immersed structures. An innovative eco-friendly approach based on the encapsulation of AF biocides in engineered nanomaterials (e.g. mesoporous silica nanocapsules (SiNCs)) has recently been applied to control the leaching rate and the environmental impacts of AF biocides when used as additives in coatings. Thus, the present study aims to: (a) assess the toxicity towards marine species of three innovative AF nanomaterials: SiNCs loaded with DCOIT (SiNC-DCOIT), SiNCs coated with silver (SiNC-Ag), SiNCs loaded with DCOIT and coated with silver (SiNC-DCOIT-Ag), and free counterparts (DCOIT, ionic silver and empty SiNCs) and (b) test if encapsulation reduces the toxicity of biocides to non-target species maintaining the anti-fouling efficacy against target species. To achieve this goal, eleven marine species (three target and eight non-target) were exposed to the test compounds, following standard protocols, with adaptations for some species. DCOIT and silver were found to be very to extremely toxic to the target and non-target species tested. Encapsulated biocides reduced their toxicity towards non-target species while showing good AF performance towards fouler species. The present study demonstrated that the encapsulation of DCOIT and silver in silica nanocapsules is a promising, efficient and more environmentally-friendly anti-fouling solution compared to free commercial biocides.
keywords
MESOPOROUS SILICA NANOPARTICLES; ANTIFOULING BOOSTER BIOCIDES; ACTIVE CORROSION PROTECTION; 4,5-DICHLORO-2-N-OCTYL-4-ISOTHIAZOLIN-3-ONE DCOIT; GROWTH; NANOCAPSULES; MACROALGA; IRGAROL-1051; ECOTOXICITY; KINETICS
subject category
Chemistry; Environmental Sciences & Ecology; Science & Technology - Other Topics
authors
Figueiredo, J; Oliveira, T; Ferreira, V; Sushkova, A; Silva, S; Carneiro, D; Cardoso, DN; Goncalves, SF; Maia, F; Rocha, C; Tedim, J; Loureiro, S; Martins, R
our authors
Projects
acknowledgements
R. Martins is funded by national funds (OE), through FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract indicated in numbers 4, 5 and 6 of article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. R. Martins (SFRH/BPD/93225/2013), V. Ferreira (PD/BD/52568/2014) and D. Cardoso (SFRH/BD/52569/2014) were awarded with grants by the Portuguese Science Foundation (FCT), funded by the Human Potential Operational Programme (POPH) through QREN and European Social Fund (ESF) and by national funds through the Portuguese Ministry of Science, Technology and Higher Education (MCTES). Joana Figueiredo was awarded with a grant (BI/UI50/8183/2018) from the research project SMARTAQUA (MARTERA/0004/2017, MarTERA, ERA-NET-H2020) and Sandra F. Goncalves was awarded with a grant within the research project FENOMENO (ERA-SIINN/0002/2013). This project was carried out in the framework of the bilateral project Exposure and bioaccumulation assessment of anti-fouling nanomaterials in marine organisms from temperate and tropical waters funded by FCT and CAPES. The financial support of CESAM-Centre for Environmental and Marine Studies (UID/AMB/50017/2019) and CICECO-Aveiro Institute of Materials (UID/CTM/50011/2019) to FCT/MCTES through national funds is also acknowledged. The authors would like to thank Dr. Abel Ferreira for providing technical support.