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

In recent years, with the increasing of the ocean drilling platforms and marine traffics, sea spill incidents occur frequently. Composing with solvent and surfactant, oil dispersant has been widely used in the treatment of oil spill emergency accidents. However, the dispersant itself is toxic, whether it will produce toxic effect on the growth of marine organisms or not is unknown.Marine microalgae is high-quality plant baits of Marine fish, such as prawn and crab larvae animals, and it’s characteristics include short training periods and high sensitivity. This article selects three kinds of representative algae of Jiaozhou Bay ——P.helgolandica, Pavlova viridis, Phaeodactylum tricornutum, oil emulsion solution is studied on the acute toxicity of three kinds of micro algae, and compared with the oil disperants and the dispersion of crude oil after physical dispersion.The results show that:(1) After add oil spill dispersant GM-2(the concentration range of 0~105 mg/L) to the dispersion of crude oil, toxicity of oil emulsion solution is less toxicity than the dispersion. The 96 h-EC50 values of crude oil dispersion to the P.helgolandica, Pavlova viridis, Phaeodactylum tricornutum were 5.44 mg/L, 3.8 mg/L, and 1.35 mg/L, respectively. The 96 h-EC50 values of crude oil emulsion to these three kinds of algae were 33.09 mg/L, 31.81 mg/L, and 13.01 mg/L, respectively; The 96 h-EC50 values of GM-2 oil spill dispersant against these algae were 81.20 mg/L, 75.46 mg/L, and 65.80 mg/L, respectively. From the 96 h-EC50 values of three marine algae, the toxicity order is: crude oil dispersion > crude oil emulsion solution > oil spill dispersant.(2) The sensibility of these three kinds of algae is: Phaeodactylum tricornutum > Pavlova viridis > P.helgolandica.According to the value of 96 h-EC50 and 96 h-EC50-chl-a, exposure to GM-2 oil spill dispersants, crude oil dispersion and crude oil emulsion, the sensitive of these three kinds of algae is: Phaeodactylum tricornutum > Pavlova viridis > P.helgolandica. Phaeodactylum tricornutum is the most sensitive algae.(3) According to the values of 96 h-EC50, the sensibility of the chlorophyll a is greater than the cell density, and more suitable as the index of oil pollution.In conclusion, adding dispersant(the concentration range of 0~105 mg/L) to crude oil dispersion will not increase the toxicity of dispersion, and chlorophyll a of Phaeodactylum tricornutum is the most sensitive indicators of these algae, more suitable for evaluating the toxicity of oil dispersion, emulsion solution, and oil spill dispersant.