Toxicity of innovative antifouling nanomaterials on neotropical and subtropical marine benthic invertebrates

Abstract

After banning the tributyltin (TBT) as an antifouling agent, many chemical compounds have been tested as active principles of antifouling 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 antifouling paints. Nanomaterials also have been used as antimicrobial substances, especially silver nanoparticles (AgNP). New antifouling compounds have been developed, incorporating nanocapsules of silica impregnated with silver and containing the DCOIT to reduce the environmental risks and increase the antifouling effectiveness. However, few studies are reporting the ecotoxicological effects of those substances, isolated or combined, on non-target organisms and their ecological hazards. Moreover, their respective mechanisms of action (at the 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 benthic invertebrates; this project also intends to investigate their respective mechanisms of action, in order to provide new information on the ecological hazards related to these new biocides. To accomplish that, spiked sediments containing these substances will be evaluated through acute or chronic toxicity tests using Tiburonella viscana (amphipod) and Kalliapseudes schubartii (tanaid). The effects at cellular and biochemical levels will be analyzed through biochemical and cellular biomarkers (GST, GSH, GPx, LPO, DNA damage, Caspases) and histopathological techniques, using adults of the bivalve Anomalocardia flexuosa exposed to the respective compounds. The results will provide important information for the development of new antifouling paints and the effects and hazards associated with these new antifouling biocides, which will help reduce the environmental impacts related to these paints-the establishment of environmental laws and enforcement.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 benthic invertebrates; this project also intends to investigate their respective mechanisms of action, in order to provide new information on the ecological hazards related to these new biocides. To accomplish that, spiked sediments containing these substances will be evaluated by means of acute or chronic toxicity tests using Tiburonella viscana (amphipod) and Kalliapseudes schubartii (tanaid). The effects at cellular and biochemical levels will be analyzed through biochemical and cellular biomarkers (GST, GSH, GPx, LPO, DNA damage, Caspases) and histopathological techniques, using adults of the bivalve Anomalocardia flexuosa exposed to the respective compounds. The results will provide important information for the development of new antifouling paints, as well as on the effects and hazards associated to 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)