Here is a file on a contaminated site. File. Save the file to your desktop, open RISC and use RISC to open this file. It has an analysis of two chemicals spilled to the soil that may migrate through the groundwater and contaminate a down-gradient well. The file has all the data entered to bring you all the way through step 3. Click on step 3, step 3d, view results, and on the right hand side, click on both benzene and di-n-butylwhatever. Then on view and you should see a graph of the concentration in the well of the two chemicals, one is zero and one reaches a peak about year 28.
Now click on New for a blank file. Click on through the same path and note how many of the parameters are already loaded as defaults. Then go back and pull up the file I sent you. Go back to step 1 (when in doubt, click on "continue") Now click on Step 1 and add your favorite chemical to the list. Choose a favorite with a log Kow between 2 and 3. Then click on through the program, you'll need to enter the point concentration in step 3b and click the simulation in step 3c. You can see three chemicals on the view at step 3d.
You should see all three chemicals in the same graph. If you don't see yours,
try selecting a chemical with a smaller Kow and/or increasing its concentration.
For homework:
1. After you get all three chemicals on the same graph, one is zero, the other
two are visible, save the file with the first 4 letters of your name, followed
by 1.
2. Now start from the beginning and deselect my two chemicals, so you are only
working with yours.
3. Go back and vary the parameters in step 3. Vary the hydraulic gradient and
re-simulate and observe how the concentration of the chemical in the well varies.
Then do the same for the Soil type. Try gravel. Note how the porosity changes.
Finally, enter or vary a degradation rate. What happens to the concentrations?
4. In the characteristic of the unsaturated zone, change the "infiltration
rate." This is usually the annual rainfall. What happens?
5. Vary the well location.
Send me two files:. One, the file you saved with your chemical and its concentration in the well visible. Two, a Word document, two paragraphs long. Describe what happens to you chemical as you vary those parameters. If time and money were limited, which of those parameters do you think would be most worthwhile to spend your efforts evaluating further?