The use of mysidopsis juniae as test organism for evaluation of acute and kinetics of acute toxicity from soluble fraction of the gasoline used in Brazil

抄録

The aim of this study is to evaluate the acute toxicity and kinetics of the toxicity of soluble fraction of gasoline. We prepared a stock-solution with 50 ml of gasoline and 950 ml of deionized water. This mixture was stirred for a period of 24 hours to separate the water-soluble portion. For the toxicity trials concentrations used were 0.1%, 0.5%, 1%, 1.5%, 2%, 4% and 10% (volume / volume) prepared in reconstituted seawater in 200 mL flasks. In order to set up the test, 5 organisms between 3 to 5 days old were placed in each flask, with reconstituted seawater. The test conditions were 32 for salinity, 12h light and 12h darkness for photoperiod and 25 °C for temperature. The organisms were fed once a day with Artemia sp. The count was made every 2 hours to complete 12 hours and after which the count is made every 12 hours to complete 48 hours. The LC50 (48 h) calculated by Probit method and was 1.97%. For the kinetics of toxicity was possible to achieve acute effects after 6 hours of test. At concentrations below 2% the effects were absent after 36 hours of testing. At 4% concentration, the effects remained until the 48 hours, while at 10% concentration mortality of the population after 2 hours of test was 100%. The use of Mysidopsis juniae made it to be possible to evaluate the toxicity of gasoline and it is necessary that the substance is handled with care to minimize environmental risks.