Ia Water Lab

The samples for this experiment were collected in different sections along the Big Sioux River with a water bottle. Each water bottle was rinsed three times before collecting the sample.

All the samples were collected between November 18th and 19th of October and frozen until they were analyzed on November 2nd, and November 3rd. Four maps were used to locate the different sites. ( Figure 1 shows each of the sites that the water samples were collected from.) The first site was located before the river enters into the city. The water was murky from far away, flowed at a slow steady rate, there were cows upstream, and corn fields surrounded the area. The second site was located near Yankton Trail. The water was dark and murky, a fertilized soccer

Map of the Big Sioux River. (Shows each of the sites that the water samples were collected.)

There were seven sites analyzed. Seven of them were taken from the river and the other sample was obtained from the drainage pipe of Wastewater Treatment Plant. To analyze each sample, nine different groups of classes conducted this experiment.

The analysis of each sample was done with a spectrophotometer. The spectrophotometer is a measurement of the reflection or transmission properties of a material as a function of wavelength. The wavelength uses a specific light that reflects and determines the different levels of concentration such as nitrates, phosphates and ammonia. The spectrophotometer uses light to measure the concentration of a compound by finding the quantity of light absorbed by the solution.

The spectrophotometer measures two things the transmittance and the absorbance. The transmittance is the amount of light and color that passes through the sample and the absorbance is the amount of light absorbed by the sample. For all of these tests, the samples were put in a reagent. The reagent change the color of the solutions to show the amount of nutrient. The light changes showing how much is absorbed and then detected by the spectrophotometer, giving the information in concentrations. Besides to measure the turbidity, or clarity, to make a true test of water quality. The water was put in the machine showing if there is a high amount of sediment or algae. Finally, to measure the conductivity in the sample, an electric stirring rod was used to in order to detect dissolved