abstract
Biofouling is a global problem that affects virtually all the immersed structures. Currently, several novel environmentally friendly approaches are being tested worldwide to decrease the toxicity of biocides in non-fouling species, such as the encapsulation/immobilization of commercially available biocides, in order to achieve control over the leaching rate. The present study addresses the toxicity of two widely used booster biocides, zinc pyrithione (ZnPT) and copper pyrithione (CuPT), in its free and incorporated forms in order to assess their toxicity and anti-fouling efficacy in target and non-target species. To achieve this goal, the following marine organisms were tested; the green microalgae Tetraselmis chuii (non-target species) and both target species, the diatom Phaeodactylum tricornutum and the mussel Mytilus edulis. Organisms were exposed to both biocides, two unloaded nanostructured materials and nanomaterials loaded with biocides, from 10 mu g/L to 100 mg/L total weight, following standard protocols. The most eco-friendly and simultaneously efficient anti-fouling solution against the two photosynthetic species (nanoclays loaded with ZnPT) was then tested on mussels to assess its lethal efficacy (LC50 = 123 mu g/L) and compared with free biocide (LC50 = 211 mu g/L) and unloaded material (LC50 > 1000 mu g/L). A second exposure test with sub-lethal concentrations (lower than 100 mu g/L), using mussels, was carried out to assess biochemical changes caused by the tested compounds. Oxidative stress, detoxification and neurotransmission markers were not responsive; however, different antioxidant patterns were found with free ZnPT and loaded nanoclay exposures. Thus, the immobilization of the biocide ZnPT into nanoclays proved to be a promising efficient and eco-friendly anti-fouling strategy.
keywords
ACTIVE CORROSION PROTECTION; MUSSEL MYTILUS-EDULIS; ZINC PYRITHIONE; ACETYLCHOLINESTERASE ACTIVITY; ANTIFOULING BIOCIDES; ENVIRONMENTAL FATE; COPPER PYRITHIONE; ACUTE TOXICITY; COATINGS; NANOCONTAINERS
subject category
Biotechnology & Applied Microbiology; Marine & Freshwater Biology
authors
Avelelas, F; Martins, R; Oliveira, T; Maia, F; Malheiro, E; Soares, AMVM; Loureiro, S; Tedim, J
our authors
Eliana Manuela dos Santos Silva Malheiro
Research Fellowship
Frederico Calheiros Maia
PhD Student
João Tedim
Associate Professor
Roberto Carlos Domingues Martins
Post-Doc Fellowshipacknowledgements
This work was supported by the BYEFOULING project, funded by European Union through the Seventh Framework Programme for research, technological development and demonstration (Grant agreement no. 612717). We acknowledge for the financial support to CESAM (UID/AMB/50017), CICECO - Aveiro Institute of Materials (POCI-01-0145-FEDER-007679; UID/CTM/50011/2013) and FCT/MEC through national funds and co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Roberto Martins and Joao Tedim benefitted from a Post-Doctoral grant (SFRH/BPD/93225/2013) and a Researcher grant (IF/00347/2013), respectively, awarded 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 Education and Science. Susana Loureiro has a fellowship from the program "Science Without Borders" from CAPES (Project #106/2013).