| China is a big importer of oil.Demand of oil has been rising increasingly in recent years,so drives the vigorous development of marine oil transportation.However the frequency and the scale of oil spill accidents,which caused by ship leaking and explosion of drilling rigs,are in upward trend.This would lead the serious destmction to the steady state of the marine environment.For quantitatively evaluating the extent of the damage comes from oil spill pollution on marine fisheries and marine ecological environment.It is essential to carry out the acute toxicity research of oil pollution on marine organisms,and to provide reliable data.This thesis studied single and compound acute toxicity effect of 180# fuel oil and 3 types of oil spill dispersants on luminescent bacteria.The experimental groups were 180# fuel oil water-accommodated fraction(WAF),one 180# fuel oil biologically enhanced WAF and two chemically enhanced WAF(BEWAF,CEWAFl,CEWAF2).We also senhe blank group (B) and three control groups of oil spill dispersants(DB,DCl,DC2).The relative light units of all the groups were determme per minute within 15 minutes,also determined at 30 min,45min,60 min.After finishing the data,the time-effect scatter plots and concentration-effect scatter plots of 15 min were drawn.15min-EC50 was obtained through unlinear fitting by Origin 8.0,and then the toxicity of each experiment:al group was determined.Matlab software was used to establish the concentration-time-effect surface and make model fitting.Based on the experimental data can be seen,in groups of 180# fuel oil dispersions(WAF)and dispenied oil the EWAF,CEWAFl,CEWAF2),the luminescent inhibition value did not change significantly over time.When concentrations were low,the luminescent inhibition value remained nearly unchanged.Each group as the concentration increasing,had a upward trend at 8 min.The trend of these groups was in 5.578mg/L,5.578 mg/L,2.656,mg/L,1.897mg/L,and 15min-EC50 of WAF,BEWAF,CEWAFl,CEWAF2,respectively for the 6.513mg/L,4.890 mg/L,3.991 mg/L,2.806 mg/L.These data revealed the toxicity of BEWAF is lower than CEWAFl,CEWAF2.And the order of toxicity is WP oil spill dispersant <BL919 < GM-2.The inhibition values of oil spill dispersants control were almost the same as the blank group,which showed the toxicity of dispersants are quite small,even non-toxicity.Concentration-time-effect surface could directly reflect the relationship between the inhibition value and three-dimensional change between the concentration and time.Similarly,the change of toxicity effect with the time trend was not obvious,but it was significant with concentration.Inhibition value of each group was in the trend of rising along with the concentration,but their change along with the time was in a lesser extent and at around 8th minute slightly rising trend was appeared.Application of luminescent bacteria toxicity assay for pollutants analysis has become the focus of current Ksearch.Luminescent bacteria is a kind of inferior organism in the ocean,and it is a significance of himinescent bacteria for ecological toxicity assessment of pollutants as biological toxicity indicators.Especially in oil toxicity is seldom used,the method of this thesis can provide available information and reference value for the toxicity study of other oil products.It can also open up a new orientation in the field of oil spill toxicity test by luminescent bacteria.Results in the data and fitted model are available as reference and data support to oil spill risk assessment. |
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