Where Are All the Nitrates Coming From? (page 3)
Gravel Run is a ground water fed stream that is located behind Queen Anne's County High School and Centreville Middle School. It is a tributary to the Corsica River, which feeds into the Chester River. Gravel Run is a very healthy stream in means of pH, dissolved oxygen, turbidity, and temperature, but is poor in nitrate readings. This stream has a nitrate range from about 0 to 12 ppm (parts per million) and has an average nitrate reading of about 7ppm. Within a stream, you only want a nitrate reading no higher than 2ppm at the most, any more than that, a lot of aquatic animals (fish) cannot survive there. When we have too many nitrates, we have an over abundance of algae, and when the algae dies, the decaying process takes up too much oxygen. Then when that happens, aquatic organisms die.
The Smart Colorimeter
The Smart Colorimeter is a machine that is put out by LaMotte. This device measures the amount of colored light that can go through a test tube. Each of the chemical tests that a person can perform with this machine turns the sample a certain color. With the Nitrate- Nitrogen test, the sample turns the color pink, the brighter the color, the more nitrates you have.
I believe that the wells near the agricultural field will have more nitrates. Based on my background reading, I have discovered that nitrate travel through water, and that farmers use those nitrates to feed their crops, so because of excess nitrates left on farm fields, wells number 3 and 4 should have higher nitrates. Wells number 1 and 2 should have fewer nitrates than the other two wells because of the few nitrates that the school puts on its property.
- 2 Gallon Bucket
- 1 hammer
- 4 Dissolve Oxygen Bottles labeled 1, 2, 3, and 4
- Water Sampler
- 4 Groundwater Wells
- Measuring Tape
- Pliers- to adjust the wire on the sampler
- Hand Pump
- Nitrate High Chemicals and Directions
- 4 Beakers
- 4 100mL Graduated Cylinder
- 2 25mL Graduated Cylinder
- Distilled Water
- 4 Colorimeter bottles
Procedure for Collecting the Samples
- Gather all materials.
- Go to well #1.
- Using the hammer, take the lid off the well.
- Use the procedure for pumping out the water in the well.
- Take out the pump.
- Place bottle #1 into the sampler and remove the cap.
- Using the sampler, submerge the bottle in the well until the bottle is filled with water.
- Take out the bottle and replace the cap.
- Repeat all of the steps for well # 2, #3, and #4.
- Repeat all of the procedures once a week.
Procedures for Pumping out the Water in the Well
- Find the volume of water in the well (depth times pi radius squared)
- Place the pump into the well.
- Pump out one volume of water into the bucket.
- Dump the bucket.
Procedure for Testing the Sample
- Label each of the colorimeter bottles to coincide with the well number.
- Using one of the graduated cylinders, pour out 160mL of distilled water into a beaker.
- Rinse the graduated cylinder in the sink.
- Using the same graduated cylinder, pour 40mL of sample #1 into your beaker.
- Using the colorimeter, follow all steps for how to do a nitrate high test.
- Record the data.
- Repeat all of the steps for each sample.
Procedure for Colorimeter
- Press the USE button to turn on the colorimeter.
- Scroll down and select ALL TESTS from TESTING MENU.
- Scroll and select 25. NITRATE-N from menu.
- Rinse a clean colorimeter tube (0967) with sample water. Fill to 10mL with sample.
- Insert the tube into the colorimeter chamber and select SCAN BLANK.
- Remove tube from colorimeter and pour off 5mL into graduated cylinder. Discard remaining sample.
- Pour the 5mL sample from a graduated cylinder into the colorimeter tube. Use the graduated cylinder to measure 5mL of *Mixed Acid Reagent (V-6279) and add to tube. Cap and mix. Wait approximately 2 minutes before proceeding to Step 8.
- Use the .1 g spoon (0699) to Add two measures of *Nitrate Reducing Reagent (V-6279). Cap.
- Hold the tube by index finger and thumb and mix by inverting approximately 50-60 times a minute for four minutes. Wait 10 minutes for maximum color development.
- At end of 10 minute waiting period, insert tube into colorimeter chamber and select SCAN SAMPLE. Record results.
- Press OFF button to exit to previous menu or make another menu selection.
Hypothesis After Preliminary Data
I believe that the wells on the school property, wells 1 and 2, will have a higher nitrate reading, based on the preliminary data above. There are variables that could affect how this could happen without my control. They are, that the groundwater spring that I have tested could have gotten the nitrates from the farm fields that are across the street from the school and that there is runoff or groundwater coming off the parking lot and road itself.
Based on my data, I can draw several conclusions. First, I can see that there are more nitrates coming off of the schools property then there is coming off of the agricultural field area. Second, there seem to be more nitrates come from the lower elevated wells, numbers 2 and 4, than the higher elevated wells, numbers 1 and 3. Third, there seems to be a low standard deviation for each of the wells. Lastly, I can say that within all of my samples, the data very rarely strayed from a particular range.