If you entered the numbers correctly in the simulator on the previous page, you should have finished with a final concentration of about 5.97 mg/liter. Of course, what we want to know is how many milligrams of the gasoline escaped during the time in question, so we have a few more calculations to do before we're done.
First we need to get the amount of gasoline (in milligrams) still in the reservoir. To do this, multiply the concentration by the total volume of the reservoir in liters, which we found was (898,800)(3.79) or 3,406,452 liters. So the amount of gasoline in milligrams which is still in the reservoir at is (5.97 mg/l) (3,406,452 l), or approximately 20,340,000 mg. The initial amount was 10 gallons, or 37.9 liters, and as gasoline has a density of about 800,000 mg/l, we then had originally about 30,320,000 mg spilled. Thus we have lost a total of about 10,000,000 mg into the stream, so it looks like cleanup will have to proceed.
You should now be familiar with how to use the lake simulators in this module. In general when you are using this module to solve a problem, you will need to: