Environmental impacts of oil on the East Coast of the Brazilian Northeastern coastline: sediment toxicity on aquatic organisms and environmental risk.

Author(s)

Maysa Ueda de Carvalho

• Document type: Master's Dissertation
• Press: São Vicente. 2023-05-05.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. São Vicente
• Defense date: 2023-03-15
• Advisor: Denis Moledo de Souza Abessa; Lucas Buruaem Moreira

Abstract

Since August 30th, 2019, tons of crude oil from a mysterious origin started reaching the Brazilian Northeastern (NE) coast, spreading across the coastline of 11 states and causing a set of environmental impacts including the contamination of more than 55 marine protected areas. After reaching the coast, the oil is subjected to multiple transformation processes, which include its spreading in different environmental matrices and the consequent harmful effects on a range of organisms. This study aimed to analyze the toxicity of sediments collected from different regions affected by the oil. Sediment samples were collected from beaches of Ceará (CE), during the oil arrival, while sediments from reef zones of Pernambuco (PE) and estuarine areas of Bahia (BA) were collected months after the incident. The sediments were characterized for their chemical, sedimentological, and ecotoxicological profiles. The toxicity assessment included three types of exposure: (1) whole sediment, for acute toxicity with the marine amphipod Tiburonella viscana and chronic toxicity with the estuarine copepod Nitocra sp.; (2) elutriates; and (3) sediment-water interface, both evaluating the chronic toxicity on sea urchin (Echinometra lucunter) embryos and Nitocra sp. The results were integrated through principal component analysis (PCA). The sediments from CE beaches exhibited relevant concentrations of PAHs and toxicity for all organisms. In turn, in sediments from PE, toxicity was strongly related with the levels of ammonia and coarse grain size, and a decrease of acute toxicity to T. viscana was observed at samples from Janga and Carneiros beaches. Most samples were toxic for E. lucunter and Nitocra sp. All samples from BA were toxic in at least one test, and some showed high concentrations of PAHs and ammonia. In some areas of BA, the low hydrodynamics may have favored the accumulation of oil components in the sediment. In some sampling sites, such as Baía de Todos os Santos and others from PE, the sediment toxicity was likely influenced by other contaminants and high levels of natural ammonia. Ecotoxicological studies with tropical organisms are essential for the effective assessment of environmental impacts and risks resulting from oil spills and should be considered tools within contingency plans and emergency response actions for oil spills that affect Brazilian coastal ecosystems. Keywords: Ecotoxicology; petroleum; marine animals; environmental emergencies; marine pollution. (AU)

• FAPESP's process: 20/04779-6 - Environmental impacts of oil on the east coast of the Brazilian Northeast Coast: sediment toxicity on aquatic organisms and environmental risk
• Grantee: Maysa Ueda de Carvalho
• Support Opportunities: Scholarships in Brazil - Master