Principles of Chem Reactivity
Comparative Analysis of McCloud’s Run and Indian Creek
There are four important traits of any water stream in the natural world. The chemistry of the stream affects the ecosystem of the stream which includes people who utilize the water of the stream for various uses. Many factors play a part into the chemistry of the water such as the temperature, the pH, the turbidity, the conductivity, and the dissolved oxygen (A.K.A. DO) (1). Those are the focus of this study. Temperature and dissolved oxygen are both related to each other. The dissolved oxygen is inversely proportional to the temperature of the water. Anything decaying in the water will decrease the dissolved oxygen. A value less than 5 mg/L of dissolved oxygen is hard on the fish. When the dissolved oxygen has a value less than 2 mg/L, the fish will die (1). pH helps not only stabilize certain communities of species, but can also be detrimental to certain species. The pH can help us predict what kind of life could be in there. For example, algae produce CO2 which will lower the pH, a lower pH may help us determine if there is a large amount of algae in the stream. It also can indicate how many acidic chemicals are leaking from human influence (1). The turbidity shows how cloudy the water is, but tells us how much extra sediment there is in the water. This can be a sign of erosion into the water. The value can also increase if the water is cloudy from a recent rain. Turbidity in higher values has a negative effect on the eggs of the fish as well as the aquatic wildlife in general (2). Conductivity measures the amount of salts in the water. The different salts are broken up and cause the conductivity to be higher when more salts are present. Algae will reduce the amount of carbonate in the water which will reduce the amount of conductivity. On the other hand a large amount of conductivity will have a negative effect on the environment (2). Method and Results:
Before we used the devices in the field we calibrated them the week before.
We utilized a DO meter which was turned on and when the water passes through the electrode the decrease in the oxygen will show the amount of DO in the water. It must be cleaned by DI water and then tested in DI water to collect a control. The water thermometer was attached to the DO meter.
The turbidity meter measures a scatter of light at a 90 degree angle. If there is a scratch in the cuvets, silicon oil is used to take away the scratches because that will affect the sample. The device is calibrated to 0 when distilled water is placed in it and the abs reading should be zero as well. When a real sample was placed in, the device would read the absorbance after the start button is pressed.
The pH meter is tested by having the probe be placed in DI water which should have a pH of 7. (we had many issues with the pH meter because it wouldn’t calibrate correctly the first time) After the probe has settled it was placed in a solution with a pH of four and we waited until it was settled. When it was settled and the pH was not 4 we adjusted the 4/10 knob on the pH meter until the pH read 4. After testing the pH meter, it should be rinsed with DI water and have its cap placed back on the probe to keep it moist. When it would test field material it would be rinsed with DI water and placed in the solution until the pH reading became steady.
The conductivity meter was tested by turning it on and rinsing it with DI water. It had to be submerged in a homogenous liquid to measure the conductivity in uS. Two readings had to be given to calibrate the conductivity meter. The meter had to be placed in DI water and tested as well as a lab standard sample. The meter read the DI water as 16 and the lab standard sample which had a true uS of 1409 as 1424. When tested in the field, it is rinsed with DI water and then placed in the field solution until the...