Oil+Removal+Toxicity

**Final Lab Comparing the Effectiveness and Toxicity of Oil and Oil Removal Procedures on Elodea. ** **Rachel Yost-Dubrow and Hannah Ibele. ** This lab was intended to confirm the effectiveness of several oil spill removal methods while measuring the adverse effects on marine plants. The methods tested were the use of a dispersant, burning the oil slick, and allowing natural weathering to run its course. Each method tested the percent transmittance of the water, the dissolved oxygen content, the appearance of the liquid under a microscope, the movement of chloroplasts in the Elodea, and the general appearance of the samples. The results showed that the dispersant was most effective at removing oil from the surface of the water, but also the most toxic to plants. Burning and natural weathering were similarly ineffective at removing the oil slick from the surface. Oil spills are common occurrences in modern society, and the issue of removing oil while not harming marine plants and animals remains very important. Thus, this lab tested solutions to a pressing issue that is of great significance in modern society. Key terms: Oil Slick, Dispersant, Burning, Natural Weathering, Percent Transmittance, Dissolved Oxygen, Effectiveness, Toxicity This graph shows the relative effectiveness of each method for removing oil that was tested in this lab. The rating was done on a scale from 0-5 with 5 constituting no oil on the surface of the water. A zero was defined as having no oil be removed from the surface of the liquid for the duration of the experiment. The Control 2 and 3 samples were given 1’s because some of the oil was seen floating in solution. Natural weathering can be assumed to be responsible for this. This graph shows the three samples that were tested for both effectiveness and toxicity to Elodea. The Control 1, Control 2 and Dispersant Fresh were the only samples that had elodea in them and had the testing carried out in the same container as the only holding the plant. Thus they were the only samples in which this kind of comparison could be done. Toxicity was rated on a scale from 1-5, with the death of the plant constituting a 0. The movement of chloroplasts and dissolved oxygen content of about 8 mg/L or over constituted a 5 (Lewis). The same rating system was used for the effectiveness scale as was used in Graph 1. This is a picture of the Spectrophotometer that Hannah used to find the transparency of the liquids in each sample This is a drawing of the process used for finding the dissolved oxgyen content of the liquids in each sample. It involved a few precipitates and a titration.

Our audacity recording covering the main ideas of our project: media type="file" key="hannah and me.wav" width="300" height="50" Journal Article Citations:  French-McCay, D. P. (2004), Oil spill impact modeling: Development and validation. Environmental Toxicology and Chemistry, 23: 2441–2456. doi: 10.1897/03-382

Fuller, Chris and Bonner, James. (2001). Comparative toxicity of oil, dispersant, and dispersed oil to Texas marine species. Retrieved from International Oil Spill Conference website: []