Toxicity of Sediments from the Piratininga-Itaipu Lagoon System (RJ) on the Bioindicator Amphipod Tiburonella viscana

• Grant number: 24/20100-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Denis Moledo de Souza Abessa
• Grantee: Sofia Hart Rodes
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Increasing urbanization in coastal regions has caused impacts on aquatic ecosystems, including chemical pollution. Particularly, tropical coastal lagoons, which represent priority environments for conservation, have been seriously affected by urban pollution. The Piratininga-Itaipu Lagoon System (Niterói, RJ), is an environment affected by anthropogenic stressors resulting from urbanization, facing problems such as siltation and eutrophication, and, possibly, sediment contamination. In this scenario, chemical analyses are insufficient to estimate environmental quality, as they do not encompass biological effects; therefore, the use of ecotoxicological approaches is necessary to provide an integrative overview of the ecological impacts of contamination. This study aims to evaluate the acute toxicity of sediments from the Piratininga-Itaipu lagoon system on the amphipod Tiburonella viscana, and determine, for some samples, the chemical groups involved with toxicity. Toxicity tests will be performed with sediments collected at 21 sampling sites, plus a control sediment (Ilhabela, SP), in which the amphipods will be exposed for 10 days (10 org/replicate; 3 replicates), under controlled conditions, following the protocol established by ABNT. The survival of the amphipods in each sample will be compared with the control group using the Student t'-test (p<0.05), allowing the classification of the sediments as non-toxic or toxic. Subsequently, two samples of sediments considered toxic will be analyzed by Toxicity Identification and Evaluation (TIE), aiming to determine the chemical groups associated with toxicity. To achieve that, these samples will be manipulated to reduce ammonia levels (treatment with Ulva sp. algae), immobilize metals (use of Fenton's reagent), and reduce the bioavailability of organic compounds (addition of coconut straw), then new tests will be performed with the raw (baseline) and manipulated samples. The results obtained in the treatments will be compared with those obtained with the baseline samples and the controls. This will provide a diagnosis of the toxicity of the sediments in the lagoon system, and the determination of the possible causes of the toxicity.