ABSTRACT. The high toxicity of diesel components makes oil spills a threat to the biota in coastal marine environments.The genotoxic effect of the diesel water-soluble fraction (DWSF) on Hippocampus reidi (Ginsburg, 1933) was assessed. Fish were exposed to three different DWSF dilutions for up to 96 hours, and genotoxicity was analyzed using the micronuclei test and the comet assay. The micronuclei test revealed no significant differences between any of the DWSF dilutions and the control in the 24-hours period; however, micronuclei increased in fish exposed to 1:500 and 1:100 DWSF dilutions for 96 hours. For all dilutions, there was an increase in micronuclei in fish exposed for 96 hours when compared to those exposed for 24 hours. The tested dilutions increased frequencies of cell classes 2 (medium damage) and 3 (large damage) in the comet assay after 24 and 96 hours. Fish exposed to DWSF 1:100 exhibited a higher frequency of class 4 (apoptosis) cells in the 96-hours period. All dilutions increased the comet score when compared to the control at 24 and 96 hours. The micronuclei and comet tests were efficient in detecting DWSF genotoxic effects in H. reidi.

This study analyzed the effectiveness of the essential oil of Aloysia triphylla (EOA) as an anesthetic and stress reducing agent in the transport of fat snook (Centropomus parallelus). Juveniles were exposed to different concentrations

Diesel oil can be a source of contamination in aquatic environments, mainly as a result of spills. The effects of the watersoluble fraction of diesel (WSF) on Prochilodus vimboides were assessed. Fish were exposed to three different WSF dilutions for up to 96 h and were compared to a control group. Damages in the fragments of DNA were analyzed using the Comet assay. The presence of erytrocyts abnormalities was assessed by micronucleus test. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity and the accumulation of copper in gills were also analyzed. Fish exposed for 96 h had higher rates of damage than those exposed for 24 h. There was no significant difference regarding the presence of micronuclei between exposed and control fish and between 24-h and 96-h exposures. For AST, no significant difference was observed between samples collected at the two exposure times. Fish exposed to a 1:100 dilution of WSF showed higher activity of the enzyme ALT than the control fish after a 24-h exposure period. There was no bioaccumulation of copper in the gills. We conclude that the genotoxic effects of WSF in the cells are more evident in P. vimboides during an acute exposure.O óleo diesel pode ser uma fonte de contaminação em ambientes aquáticos, principalmente como resultado de derrames acidentais. Foram avaliados os efeitos da fração solúvel do óleo diesel (FSO) em Prochilodus vimboides. Os peixes foram expostos a três diferentes diluições da FSO por até 96 horas e comparados com um grupo controle. Os danos nos fragmentos de DNA foram analisados utilizando o ensaio Cometa. A presença de anormalidades nos eritrócitos foi avaliada pelo teste do micronúcleo. A atividade da Aspartato aminotransferase (AST) e alanina aminotransferase (ALT) e da acumulação de cobre nas brânquias também foram analisados. Os peixes expostos por 96 h tiveram maiores taxas de danos do que aqueles expostos por 24 h. Não houve diferença significativa quanto à presença de micronúcleos entre os peixes expostos e controle e entre 24 e 96 h exposições. Para AST, não foi observada diferença significativa entre as amostras coletadas em dois tempos de exposição. Os peixes expostos a uma diluição de 1:100 do FSO apresentaram maior atividade da enzima ALT do que os peixes do controle após um período de exposição de 24 horas. Não houve bioacumulação de cobre nas brânquias. Os efeitos genotóxicos nas células foram os mais evidentes em P. vimboides durante a exposição aguda a FSO.