Avaliação dos efeitos letal e subletais do óleo oriundo do acidente ocorrido no litoral pernambucano em invertebrados marinhos

Submitted by (lucia.rodrigues@ufrpe.br) on 2022-11-28T13:13:57Z No. of bitstreams: 1 Estefani Santana do Nascimento.pdf: 614615 bytes, checksum: 64000cf00be434c495b970d778c0b556 (MD5) Made available in DSpace on 2022-11-28T13:13:57Z (GMT). No. of bitstreams: 1 Estefani Santana do Nascimento.pdf: 614615 bytes, checksum: 64000cf00be434c495b970d778c0b556 (MD5) Previous issue date: 2022-02-25 The present study aimed to evaluate the effect of the soluble and crude fraction of the oil, which contaminated the Brazilian coast in the accident that occurred in 2019, on aquatic microcrustaceans. For this, ecotoxicological bioassays were carried out, using the benthic copepod as a test organism.Thisbe biminiensis.The bioassays with the crude fraction of the oil lasted for 1 month, with a weekly water change. 0.5 g of oil collected from 5 different beaches on the coast of Pernambuco (Enseada dos Corais, Xaréu, Cupe, Paiva and Suape), 40 mL of filtered sea water and basic ration for macerated aquarium fish were used. The bioassays with the soluble fraction of the oil lasted for 7 days, using the same proportion of the crude fraction and the same test organism. At the end of the exposure period, the content was fixed with formaldehyde and stained with Rose Bengal, for subsequent counting and determination of endpoints (number of copepods, population number and percentage of females). Observations in the stereomicroscope revealed stains in the individuals, due to this fact, a new bioassay with the crude fraction of the oil was carried out for photographic recording under the same conditions as the previous one. At this stage, at the end of the exposure period, the content was not stained with Rose Bengal for an integral observation of the microcrustacean body and confirmation of the presence of oil through the microscope. The results showed a significant decrease in the number of copepods (in the groups exposed to the oil collected in Xaréu, Enseada dos Corais and Paiva) and in the population number (in all oil samples tested). In addition, there was a feminization of the population, where it was possible to notice a significant increase in the proportion of females in oil samples collected at Paiva beach and Enseada dos Corais. Through the photographic records it was verified that the oil was ingested by the studied species, part of which contaminated the animal, and the other part was fragmented and eliminated in the fecal pellets, becoming available for other organisms. In the experiment with the soluble fraction of the oil, the survival of the organisms exposed to the bioassay was evaluated. The results showed no lethal effects in the exposed groups. Thus suggesting that the oil did not release its soluble fraction into seawater during the process of obtaining it, and consequently, did not interfere with the survival of organisms. Therefore, it was concluded that the oil which contaminated the Brazilian coast has a high toxic power for the tested organism, due to the reduction in the average number of copepods, population decline, as well as the feminization of the population. becoming available to other organizations. In the experiment with the soluble fraction of the oil, the survival of the organisms exposed to the bioassay was evaluated. The results showed no lethal effects in the exposed groups. Thus suggesting that the oil did not release its soluble fraction into seawater during the process of obtaining it, and consequently, did not interfere with the survival of organisms. Therefore, it was concluded that the oil which contaminated the Brazilian coast has a high toxic power for the tested organism, due to the reduction in the average number of copepods, population decline, as well as the feminization of the population. becoming available to other organizations. In the experiment with the soluble fraction of the oil, the survival of the organisms exposed to the bioassay was evaluated. The results showed no lethal effects in the exposed groups. Thus suggesting that the oil did not release its soluble fraction into seawater during the process of obtaining it, and consequently, did not interfere with the survival of organisms. Therefore, it was concluded that the oil which contaminated the Brazilian coast has a high toxic power for the tested organism, due to the reduction in the average number of copepods, population decline, as well as the feminization of the population. The results showed no lethal effects in the exposed groups. Thus suggesting that the oil did not release its soluble fraction into seawater during the process of obtaining it, and consequently, did not interfere with the survival of organisms. Therefore, it was concluded that the oil which contaminated the Brazilian coast has a high toxic power for the tested organism, due to the reduction in the average number of copepods, population decline, as well as the feminization of the population. The results showed no lethal effects in the exposed groups. Thus suggesting that the oil did not release its soluble fraction into seawater during the process of obtaining it, and consequently, did not interfere with the survival of organisms. Therefore, it was concluded that the oil which contaminated the Brazilian coast has a high toxic power for the tested organism, due to the reduction in the average number of copepods, population decline, as well as the feminization of the population. O presente estudo teve como objetivo avaliar o efeito da fração solúvel e bruta do óleo, que contaminou o litoral brasileiro no acidente ocorrido em 2019, em microcrustáceos aquáticos. Para isso foram realizados bioensaios ecotoxicológicos, utilizando como organismo teste o copépodo bentônico Tisbe biminiensis. Os bioensaios com a fração bruta do óleo tiveram duração de 1 mês, com troca de água semanal. Foi utilizado 0,5 g de óleo coletado em 5 diferentes praias do litoral pernambucano (Enseada dos Corais, Xaréu, Cupe, Paiva e Suape), 40 mL de água do mar filtrada e ração básica para peixes de aquário macerada. Os bioensaios com a fração solúvel do óleo tiveram duração de 7 dias, utilizando a mesma proporção da fração bruta e o mesmo organismo teste. Ao final do período de exposição, o conteúdo foi fixado com formol e corado com Rosa de Bengala, para posterior contagem e determinação dos endpoints (número de copépodos, número populacional e percentual de fêmeas). Observações no estereomicroscópio revelaram manchas nos indivíduos, devido a este fato, um novo bioensaio com a fração bruta do óleo foi realizado para registro fotográfico com as mesmas condições do anterior. Nessa etapa, ao final do período de exposição o conteúdo não foi corado com Rosa de Bengala para uma observação integra do corpo do microcrustaceo e confirmação da presença do óleo através do microscópio. Os resultados mostraram uma diminuição significativa no número de copépodos (nos grupos expostos ao óleo coletado em Xaréu, Enseada dos Corais e Paiva) e no número populacional (em todas as amostras de óleo testadas). Além disso, verificou-se uma feminização da população, onde foi possível perceber um aumento significativo da proporção de fêmeas em amostras de óleo coletadas na praia de Paiva e Enseada dos Corais. Através dos registros fotográficos constatou-se que o óleo foi ingerido pela espécie estudada, parte do qual contaminou o animal, e a outra parte foi fragmentada e eliminada nas pelotas fecais, ficando disponível para outros organismos. No experimento com a fração solúvel do óleo, foi avaliado a sobrevivência dos organismos expostos ao bioensaio. Os resultados demostraram ausência de efeitos letais nos grupos expostos. Sugerindo assim, que o óleo não liberou a sua fração solúvel na água do mar, durante o processo de obtenção da mesma, e consequentemente, não interferiu na sobrevivência dos organismos. Sendo assim, concluiu-se que o óleo o qual contaminou o litoral brasileiro tem um elevado poder tóxico para o organismo testado, por causar da redução do número médio de copépodos, do declínio populacional, bem como feminização da população.