Research On Toxicity Of Fuel Oil Processed By The Dispersant To Two Marine Organisms

Due to oil exploration, terminal operation, shipping transportation and all kinds of unexpected oil spills, large oil pollutions get into the sea, which threats the marine ecological environment. The study on toxic effect of petroleum hydrocarbons pollution to marine organisms can provide datum for quantitative assessment of the pollution’s damage to the sea, and have the important value to the control of the oil pollution. Choosing chlorella and luminescent bacteria as test species, the paper studies the toxic effect of 120# fuel oil dispersion and emulsion on them.The research first studies the effect of 120# fuel oil and water mixing ratio and oil dispersant delivery ratio on oil content, and then make the preparation program of 120# fuel oil dispersion and emulsion.Through the acute toxic effects of 120# fuel oil on chlorella, the inhibition rates and the inhibition curves of growth are obtained. The relationship between the concentration and the toxic effect can be separately fitted with Generalized Logit II and Generalized Logit I function model which have the best results. The relationship of EC50 and time can be described better with parabola function model. The research showed that the 96h EC50 value of dispersion and emulsion of 120# fuel oil on Chlorella is 5.066mg/l and 2.626mg/l, respectively, and the value of EC50 increases with time.The toxicity of 120# fuel oil to luminescent bacteria is studies. The research compares the fitting result of several functions, and concludes that the relationship between dispersion and emulsion concentration and effect can be fitted better with Generalized LogitⅡand BoxCox Logit function model. The 96 h EC50 value of 120# fuel oil dispersion and emulsion on luminescent bacteria is 2.502mg/l and 2.203mg/l, respectively. It similarly proves dispersion is less toxic than emulsion.By comparing EC50 values of 120# fuel oil dispersion and emulsion on chlorella and luminescent bacteria, the results show that the toxicity of 120# fuel oil on luminescent bacteria is more sensitive than chlorella.