EFFICACY AND ECOTOXICITY ASSESSMENT OF NOVEL MARINE FOULING-RELEASE POLYMER COATINGS

Three novel polymer coating sets were investigated for marine fouling release application. These were based on different surface-active copolymers of various architectures incorporated into a polysiloxane network matrix (tin-catalyst crosslinked, bismuth-catalyst crosslinked and UV photocrosslinked). For all coatings leachates were prepared in order to assess the effective eco-sustainability of materials via an ecotoxicological test battery composed by different marine and/or freshwater organisms (Vibrio fischeri, Dunaliella tertiolecta, Pseudokirchneriella subcapitata, Artemia salina, Artemia franciscana, Daphnia magna, Sparus aurata). The effectiveness of assessed coatings was also evaluated by a set of settlement and detachment assays conducted using different organisms (Navicula salinicola, Nitzschia sp., Amphibalanus amphitrite, Balanus improvisus, Ficopomatus enigmaticus). Detachment assays were performed with a specially developed, home-made turbulent flow channel apparatus. The development and culturing features of the serpulid F. enigmaticus were evaluated in order to possibly include this species as a new promising model organism for fouling release assays. Ecotoxicological evaluation underlined absence of acute and chronic toxicity for all assessed leachates, except for those of tin-catalysed coatings. Diatom (N. salinicola and Nitschia sp.) detachment assays underlined an algal-surface bond tenacity that increased with the hydrophilicity of the assessed surface. Barnacles (A. amphitrite and B. improvisus) settlement and dethachment assays showed different patterns of surface preferences between the two species at the larval stage. With A. amphitrite differences were also observed in settlement tenacity between larval and adult stages. The serpulid F. enigmaticus was well investigated during its development to describe best culturing conditions. Two different settlement assays were performed with F. enigmaticus larvae in order to evaluate surface preferences during settlement and to obtain organism covered slides for detachment assays. Settlement assays with F. enigmaticus underlined a surface selection behaviour similar to the barnacle B. improvisus.