The four samples were be taken back to the lab to find the amount of nitrate in the water. The group worked together to determine the nitrate levels using an ion-selective electrode (ISE). The ISE as well as the calibration curve was used to determine the nitrate levels of each of the samples. Overall, each group member was responsible for helping to collect water samples from each site and working evenly on the nitrate calculations as well as supply cleaning. Once the nitrate level for each sample was determined, the samples from each site were compared. If the mean nitrate level was higher in the water from Acton Lake than the pond, the hypothesis will be supported. If the mean nitrate level from Acton Lake was less than that off the pond water, the hypothesis will not be supported. The goal for this experiment is to see if the golf course is increasing nitrate levels in Acton Lake by comparing the nitrate level to a water sample from a site with less fertilizer run-off. The hypothesis states that the nitrate levels of the water from Acton Lake in Hueston Woods will have higher nitrate levels than the water from the pond in between Peabody Hall and the Art Museum. One thing that needed to be taken into consideration about the sample sites is the size difference. Acton Lake, at 625 acres, is far larger than the pond (). This needed to be taken into account because the concentration of fertilizer run-off might be somewhat diluted since the lake is so big. Also, any boats 3
traveling through the lake could cause a current to further spread the run-off through the lake, increasing the chance of this dilution. This research is relevant to wildlife in the area because while nitrate itself is not directly toxic to animals, if digested it is converted into nitrite. When nitrite gets into the blood system it converts hemoglobin into methamoglobin. Methamoglobin cannot transport oxygen as efficiently and the animal could die ( ). This means that if the fertilizer run-off is causing a high nitrate level in Acton Lake, the animals that get water from the lake might be at risk. Methods: Analysis of the Validation Standards and Environmental Samples: A nitrate stock solution was prepared during the first week in order to make standard solutions in the following weeks. This was done by rinsing the glassware using the cleaning procedure, which includes rinsing first with detergent and tap water, then three times with distilled water, three times with HCl, three times with distilled water, and three times with deionized water. The 1liter of stock solution with 100 mg/L of Nitrogen was made with .725 grams of KNO 3 . To acidify the solution, 12 mL of 3.0 M aqueous H 2 SO 4 was added. The solution was transferred to a storage bottle. This stock solution was used in week two to prepare the nitrate standard solutions. After all of the glassware was cleaned using the cleaning procedure, 1, 2, 4, 6, and 10 mg/L of stock solution were transferred into separate volumetric flasks and used to make the five standard solutions.
- Spring '12
- Chemistry, Drinking water, Nitrate, Acton Lake