Toxicity of binary mixtures of new nanostructured materials: combination of corrosion inhibitors and antifouling biocides, and comparison between marine organisms from neotropical and temperate regions.

Abstract

The metallic corrosion process is one of the main causes of degradation of structures and equipment in the marine environment, to which are added the problems caused by biofouling. These problems have been minimized by the application of coatings containing antifouling biocides and chemical corrosion inhibitors (CI). However, due to the toxicity associated with biocides and IC, there is interest in replacing these compounds with effective and less toxic alternatives. Recently, new manufactured nanomaterials (NM) began to be developed, for use in the immobilization/encapsulation of biocides and IC, in order to increase their efficiency. Double layer hydroxides (LDH) have been proposed to immobilize IC, and silica nanocapsules (SiNC) to immobilize antifouling biocides. It is assumed that the entry of these new NM in the market will generate their possible co-occurrence in the environment, being necessary to study the combined effects of these new substances, comparing them with those caused by their equivalents in the free form. In this project, the ecotoxicological evaluation of binary mixtures containing the IC Sodium Nitrate (NaNO3) and Benzotriazole (BTA), and the antifouling biocide DCOIT, in free and nanostructured forms (LDH-NaNO3, LDH-BTA; and SiNC- DCOIT), using neotropical and temperate marine species. Embryo-larval development tests will be carried out on sea urchins (Echinometra lucunter; Paracentrotus lividus) and mussels (Perna perna; Mytilus galloprovincialis) in order to establish the toxic levels of mixtures containing IC and antifoulings, through inhibition of embryonic development. Based on the toxicity levels of each substance, binary combinations will be established to analyze the effects of the mixtures. The interpretation of tests involving mixtures will produce models of dependent and independent effects, and will involve the use of the MIXTOX tool to interpret the results. This study will contribute to the development of anti-corrosive and anti-fouling additives with high performance and lower environmental risk.