Where Are All the Nitrates Coming From? (page 4)
In this experiment, I was trying to find out where the nitrates in Gravel Run were coming from. To do this I had to follow quite a few procedures. The first procedure was on how to pump out the water in the well so I can be sure that any decaying material was removed to make an accurate sample. Next I had to follow a procedure on how to get my sample out of the well. My next procedures were the most complicated. After doing a one in five dilution of my sample, I then had to follow the steps on how to use the smart colorimeter on how to do the nitrate nitrogen test. I had to repeat all of those procedures for each sample and each time I sampled, which was every week for a total of six weeks.
Based on my data that I have received, I reject my first hypothesis and accept my hypothesis that I had made after my preliminary data. Well number 2, which is located next to the stream, has the highest nitrate level of all, an average of 7.26ppm. In ranking the wells by their mean ppm, well 2 is first with 7.26ppm, and then well 4 with 5.03ppm, well number 1 with 2.03ppm, and last well number 3 with 1.88ppm. There is a low standard deviation for each of the wells, well number 1 with about .72ppm, well 2 with about 3.08ppm, well 3 with about 1.23ppm, and well four with around 1.05ppm.
School vs. Farming Area
The ground water that comes off of the school property has more nitrates in it than the ground water that comes off of the agricultural field. The average nitrate level for the wells with school yard drainage is 4.65ppm, while the agricultural area has an average nitrate level of about 3.45ppm. This has a possibility of being caused by the farm field across the street from the school. It has no cover crop to keep the nitrates that the farmer puts on it from going into the ground water. The agricultural area that my wells are by has alfalfa as a cover crop to take in any excess nitrates.
Upper Properties vs. Lower Properties
There seems to be more nitrates in the wells on low elevation then there is from the high. The wells that are on the lower portion of the properties have an average of 6.15 ppm, compared to the 1.96ppm average that the high areas receive. It is entirely possible for each of the wells to be on a different groundwater steam. In all actuality, and also based on my data, this is probably true.
Time of Year
Time of year does seem to have an effect on the nitrate levels. Using the mean from all the wells for the two months of November and December, December does seem to have a higher nitrate reading. November has an average nitrate reading of 3.10 ppm to December's 4.53ppm. Why this is happening, I can only speculate.
My findings can lead up to finding the true causes of Gravel Runs high nitrate readings, and perhaps how to stop this from happening. I do believe in further study for this project, and I hope to continue finding out more information on the properties surrounding the wells, and finding out where the wells fit on a water table of the area. I also hope to find in further study, if each of the wells test the same stream or each have different streams. Since I have only tested in the late fall, there could be the significant difference of nothing being put on the farm fields. There are many variables in this project that I have not yet recognized and have yet to see if they have any affect on the nitrate levels of Gravel Run.
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Chester River Association and Centreville Middle School
Chester River Annual Water Quality Report. 1996.
U.S.D.A Water Quality Field Guide. 1983.
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Katie Lamb, 8th Grade Science Fair Project
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Baltimore Sun 3/20/1998
Thomas E. Jordan, David L. Correll, and Donald E. Weller Effects of Agriculture of Nutrients from Coastal Plain Watersheds of Chesapeake Bay. 1996.
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.