Monitoramento ecotoxicológico em sedimento de manguezal contaminado com hidrocarbonetos de petróleo

Abstract

The mangroves are constantly affected by oil spills, petrochemical industries from growing or vessels carrying crude minerals such as derivatives, among them the different types of fuels. Therefore, these environments are considered the most vulnerable ecosystems and sensitive to oil spills, due to the ease of the oil adhere to sediment causing acute and chronic effects to the entire biodiversity. Thus, one of the most accurate biological monitoring of anthropogenic impacts on ecosystems can be made through the ecotoxicological tests acute and/orchronic, with organismsthat are representative to the environment. On this basis, for a detailedassessment of an impact by spill of oil and oil products in the mangrove, the present study sought to develop a methodology for monitoring these contaminants in sediment in the preliminary round took place in a month and a final held in three months, bothwith different types of experimental units (incontainerspot and can/PET, respectively) outside its natural environment, through acute ecotoxicological tests with the bacterium Vibrio fischeri. The contaminants were tested petroleum(16.9 degrees API andheavy) and three fractions from this same hydrocarbon, with different densities compared to some types of fuel, one similar to kerosene (fraction 2, 40.6 ºAPI, light), a similar diesel oil (fraction 6, 28 ºAPI, medium) and the lastsimilar to the lubrificanting oil (fraction 12, 19.4 º API heavy). The acute toxicity was correlated with the density of oil, it always has the highest degree API higher, which was also observed an attenuation higher in experimental periods, especially in the first analysis. Sediments containing fraction 2 as a contaminant had higher initial toxicity, both for the preliminary experiments and for the definitive experiments of 81.12% and 75.46%, respectively.