Impactos ambientais do óleo na costa leste do litoral Nordeste brasileiro: toxicidade de sedimentos sobre organismos aquáticos e risco ambiental.
Data
2023-03-15
Autores
Carvalho, Maysa Ueda de
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Universidade Estadual Paulista (Unesp)
Resumo
Desde 30 agosto de 2019, toneladas de óleo bruto de origem desconhecida começaram a chegar à costa do Nordeste (NE) brasileiro, espalhando-se por 11 estados e atingindo mais de 55 áreas marinhas protegidas. Após atingir a costa, o óleo pode sofrer diversos processos de transformação, como interagir com diferentes matrizes sedimentares, podendo gerar efeitos nocivos a uma gama de organismos, comprometendo a biota local. Este estudo visou analisar o potencial tóxico de sedimentos de regiões afetadas pelo óleo, logo no início do evento em praias do Ceará (CE), e meses depois em áreas recifais de Pernambuco (PE) e estuarinas da Bahia (BA). Os sedimentos foram caracterizados quanto ao perfil químico, sedimentológico e ecotoxicológico. Em relação a toxicidade, foram empregados três tipos de exposição: (1) sedimento integral, pela toxicidade aguda com o anfípodo marinho Tiburonella viscana e crônica com o copépodo estuarino Nitocra sp.; (2) elutriatos e (3) interface sedimento água, ambos para toxicidade crônica com embriões do ouriço-do-mar (Echinometra lucunter) e Nitocra sp. Os resultados foram integrados através da análise de componentes principais (PCA). Nos sedimentos coletados no CE houve concentrações de HPAs e toxicidade para todos os organismos. Em PE, a toxicidade foi mais fortemente relacionada aos altos níveis de amônia e ao tamanho dos grãos, e houve a diminuição da toxicidade aguda para a T. viscana nas praias do Janga e Carneiros, ao longo do tempo, enquanto para E. lucunter e Nitocra sp., a maioria das amostras foi tóxica. Todas as amostras da BA foram tóxicas em pelo menos um teste, e algumas apresentaram altas concentrações de HPAs, além de amônia e sedimentos grosseiros. Em algumas das áreas da BA o baixo hidrodinamismo que pode ter favorecido o acúmulo dos componentes do óleo no sedimento. Em alguns pontos, sobretudo em PE, a toxicidade pode ter sido influenciada pelo histórico de contaminação antrópica difusa, e altos níveis de amônia natural. Estudos ecotoxicológicos com organismos tropicais são fundamentais para a efetiva avaliação dos impactos e riscos ambientais decorrentes de vazamentos de óleo, e deveriam constituir ferramentas dentro dos planos de contingência e ações de resposta a emergências por óleo que atingem os ecossistemas costeiros do Brasil. Palavras-chaves: Ecotoxicologia; petróleo; animais marinhos; emergências ambientais; poluição marinha.
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.
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.
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Palavras-chave
Toxicologia ambiental, Poluição marinha por oleo, Toxicidade, Toxicidade Testes, Petróleo, Organismos aquaticos, Água Poluição, Solos Poluição, Emergências ambientais