Toxicity of innovative anti-fouling nanomaterials in sediment exposing marine benthic invertebrates from temperate climates.

• Grant number: 24/01138-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: April 30, 2024
• End date: December 21, 2024
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Principal Investigator: Denis Moledo de Souza Abessa
• Grantee: Caio Cesar Ribeiro
• Supervisor: Roberto Carlos Domingues Martins
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil
• Institution abroad: Universidade de Aveiro (UA), Portugal
• Associated to the scholarship: 22/06164-4 - Toxicity of innovative antifouling nanomaterials on neotropical and subtropical marine benthic invertebrates, BP.PD

Abstract

In the marine environment, anthropogenic surfaces are subject to rapid colonization and accumulation of biofouling organisms, including bacteria, algae, barnacles, tube worms, mussels, and oysters, resulting in significant economic and ecological costs. To combat them, it is common to apply antifouling paints that gradually release biocidal compounds. Following the global ban on the use of organotins in antifouling coatings, various booster biocides have been introduced, including DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), known as Sea-Nine, one of the most widely used alternative antifoulants due to its effective and long-lasting performance. However, there is controversy over whether DCOIT can be rapidly degraded to prevent marine water pollution. Its extensive use and subsequent detection in water samples indicate that DCOIT is an emerging pollutant, with concentrations found in various marinas and ports around the world and accumulation in marine animals. In addition to being toxic to biofoulers, DCOIT is also highly toxic to non-target species in marine ecosystems, having a variety of detrimental effects on marine animals, delaying the development and growth of sea urchin embryos, inducing apoptosis of germ cells in the testis, disrupting the balance of sex hormones, and causing transgenerational impairment in offspring embryogenesis in fish. Recently, innovation in antifoulants has focused on silica nanocapsules containing silver (nanomaterials such as silver nanoparticles - AgNP) and DCOIT (SiNC-DCOIT-Ag), aiming to reduce environmental impacts and improve antifouling efficacy. Still, the ecotoxicological effects of these new biocides, both individually and in combination, on non-target species, especially in sedimentary environments, are poorly understood. This includes a lack of understanding of their mechanisms of action at the cellular and biochemical level. This project aims to investigate the toxicity of emerging biocidal nanomaterials (including simple and silver-impregnated silica nanocapsules, as well as those containing DCOIT) in benthic species of temperate climates. For this, chronic toxicity tests will be conducted with the following organisms: the polychaetes Hediste diversicolor and the bivalves Cerastoderma edule. The study will compare the toxicity of these nanomaterials with that of free silver salts and DCOIT, aiming to clarify the mechanisms of action of these compounds. The analysis will cover cellular and biochemical aspects, employing biomarkers such as GST, GSH, GPx, Lipoperoxidation, DNA Damage, and Acetylcholinesterase. The results of this study will provide valuable information to compare with data produced with tropical climate organisms and for the development of new antifouling paints, while also contributing to the understanding of the ecological risks associated with these compounds. This will allow the development of strategies to mitigate environmental impacts, biological monitoring, and the formulation of effective environmental policies at national and international levels.