Assessment of bioaccumulation and toxicity of innovative antifouling nanomaterials on tropical and neotropical marine invertebrates

Abstract

After the banning of the tributyltin (TBT) as antifouling agent, many chemical compounds have been tested as active principle of anti-fouling coatings, such as the DCOIT, or Sea-Nine (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), which has been employed in the formulation of third generation anti-fouling paints. Nanomaterials also have been used as antimicrobial substances, especially silver nanoparticles (AgNP). Currently, new antifouling compounds have been developed, incorporating nanocapsules of silica impregnated with silver and containing the DCOIT, with the aim of reducing the environmental risks and increase the antifouling effectiveness. However, there are few studies reporting the ecotoxicological effects of those substances, isolated or combined, to non-target organisms as well as their ecological risks. Moreover, their respective mechanisms of action (at cellular and biochemical levels) are still not fully understood. This project aims to assess the toxicity of salts of Ag, the DCOIT, nanocapsules of silica (simple and impregnated with Ag) as well as the respective nanocapsules containing DCOIT, to marine invertebrates; this project also intends to investigate their respective mechanisms of action, in order to provide new information on the ecological risks related to these new biocides. To accomplish that, aqueous solutions and spiked sediments contaminated these substances will be evaluated by means of acute or chronic toxicity tests using the following organisms: Nitocra sp (Copepod), Tiburonella viscana (amphipod), Kalliapseudes schubartii (tanaid), Perna perna (bivalve) embryos, Echinometra lucunterm (sea-urchin), and Artemia sp (Anostraca). The mechanisms of action at the cellular and biochemical levels will be analyzed through biochemical and cellular biomarkers (GST, GSH, GPx, LPO, DNA damage, ATPases, Caspases and neutral red retention assay) and histopathological techniques, using adults of the bivalve Perna perna exposed to environmentally relevant concentrations of the respective compounds. The results will provide important information for the development of new antifouling paints, as well as on the effects and ecological risks caused by these new antifouling biocides, which will be helpful to reduce the environmental impacts related with these paints, and the establishment of environmental laws and enforcements. (AU)