As someone who is interested in environmental chemistry, I designed a project where I could empirically analyze the environmental effects of something that is done every winter at Vassar, salting the roads and sidewalks.\u00a0 After the snow melts the water flows down into rivers and lakes, and it carries the dissolved rock salt with it.\u00a0 This leads to a significantly higher salt concentrations in the water which can be very harmful to many fish\/plant species.\u00a0 Over the course of 16 days I took 12 water samples the river running under the bridge building.\u00a0 I was careful to sample from around the same area each time and tried to control as many variables as possible.\u00a0 I then analyzed these samples with a Vernier Spectrometer.\u00a0 I first calibrated the spectrometer with distilled water taken from one of the Chemistry labs.\u00a0 Then, to get each data point, I would shake up the water from a specific day, then dip a cuvette into the holding jar, and run the spectrometer.\u00a0\u00a0 I analyzed each day\u2019s water two times to insure against a bad sampling.<\/p>\n
Results<\/strong><\/p>\n Figure 1.\u00a0 Raw Data from Spectrometer<\/p>\n Figure 2.\u00a0 Data organized into a chart of Mean Absorbance vs. Days After the Storm *Discontinuities on the X-Axis are a result of no data being taken on absent days.<\/p>\n Discussion<\/strong><\/p>\n I am very pleased with the results my study revealed.\u00a0 I saw different absorbance for each sample I took, with the highest mean absorbance being 8 days after the storm, which was around the time the snow was melting rapidly.\u00a0 I also observed a small, but consistent peak at around 390 nm on the readings for days 3, 8, 9, 10, 11 and 15. \u00a0Upon further research, I found that salt can absorb light at around this wavelength, so this peak could very well be rock salt runoff polluting the river. \u00a0I would also note there is one line (day 0) has a small, broad peak from 500-700 nm where all of the other lines just sloped down through the spectrum. \u00a0This could be the result of a sampling error, or something that was only present in the river on that day due to the active snowfall.<\/p>\n Although the data is not perfect, I observed an upward trend in the mean absorption as more days passed after the storm.\u00a0 This suggests that as snow from the storm melts, rock salt and other pollutants are increasing in concentration in the river due to runoff.\u00a0 This supports my original hypothesis that runoff from the snow would carry pollutants into the river.<\/p>\n Other<\/strong><\/p>\n Science that I learned during this experiment is mainly the inner workings of a UV-Vis spectrometer.\u00a0 It mainly functions by being able to disperse light into its individual wavelengths (380-950 nm) and shooting it through the sample in the cuvette.\u00a0 The detector on the far side gives a reading based on how much light reaches it, which gives us a measurement of how much light was absorbed by the sample and at which wavelength it was absorbed.\u00a0 When I loaded a blank with distilled water, I calibrated the spectrometer to have that be 0 absorbance (or 100% transmittance) and compared the river water samples to that. \u00a0This allows researchers to determine what compounds are in a sample I also learned about Beer\u2019s law which takes into account cell path length (b) in cm,\u00a0 concentration (C) in mols\/L and molar absortivity (e) in L\/mol*cm to give Absorbance, which is unit less.<\/p>\n This project fits into current science by exposing a negative environmental impact of our actions, which is a growing concern in the modern scientific community.\u00a0 It is becoming ever more important that we are conscious of the way we are affecting our surroundings, and making changes to lessen our impact.<\/p>\n If I were to repeat this experiment, I would have started taking samples earlier than 1 day before the storm to get a better baseline to compare the changes to.\u00a0 I would also take samples from more than one river so I could draw a more general conclusion, as this one river could be an outlier in either direction.\u00a0 If I had 6 more weeks, I would continue to take these samples as to see when the river returns to its original state, as when I finished, it was still above where it started.\u00a0 I would also try to identify what some of the pollutants are by spiking the samples with different compounds (like NaCl) and seeing where the peaks were enhanced.<\/p>\n Joseph Griffen<\/p>\n For my project I went to decided to examine the water quality of different drinking fountains on campus to see if the water quality across campus was the same or if certain dorms had better or worse drinking water than others. Since it would be difficult to test the quality of Vassar\u2019s water in general, I decided a better approach was to test each dorm\u2019s water quality compared with the other dorms, rather than determining the quality of Vassar\u2019s water as a whole. This means that, while my results can point to one dorm having slightly better water than another, I won\u2019t be making any assertions as to the quality of water at Vassar as a whole. For my experiment I ended up testing the water from 7 different drinking fountains, each from a different dorm. The dorms I chose were Main, Lathrop, Davidson, Joss, Jewett, Strong, and Raymond.<\/p>\n To conduct my experiment I took the water samples and placed them in a spectrometer. This shows how much light from specific wavelengths the water absorbs, which can point to there being minerals or other compounds in the water which may pollute it. If a water sample is absorbing significantly more light of a certain spectrum then it generally means that there is some particle in that water that is causing that increase in absorption. One issue with this project, however, was determining what this increase in absorption means. Some extra particles that absorb light could be perfectly harmless or the difference could be so miniscule that it wouldn\u2019t have any noticeable effect in water quality. On the other hand, the increase in absorption could indicate a contaminant that is affecting our drinking quality, perhaps not enough to make it unsafe to drink, but enough for you to stop and think twice about drinking the water. In order to determine whether certain contaminants are present in the water in significant quantities one would have to do detailed specific analysis into the spectrums of color that these contaminants absorb. This would require different, more precise equipment and testing than was able to be conducted. These results therefore, are intended to be a jumping off point, and can indicate which water fountains may have poorer water quality and which further examination of may be able to indicate pollutants in the water more certainly.<\/p>\n Graph 1: Absorbance vs. Wavelength (with visible spectrum)<\/p>\n![\"\"](\"http:\/\/pages.vassar.edu\/ltt\/files\/2017\/02\/raw-data-1.png\")
<\/a><\/p>\n<\/a><\/p>\nFinding the Purest Water Fountain on Campus<\/strong><\/h1>\n
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