Methods

Data

Biomagnification Pyramids

Conclusions

Bermuda

Nahant

Home

Collecting Samples

Collecting the water samples was very simple.  I took 50mL collection tubes, and dipped them into whatever water body it was that I wanted to collect from.  I filled the vial, capped it, and wrote its identification information on it. 

COD Test

Chemical Oxygen Demand (COD) measures the quality of effluents in wastewater by assessing the amount of oxidizeable organic matter in the sample. 

Testing Procedure:

1.  The digestor block had already been preheated to 150°C, and standards to which I could compare my results were previously prepared.

2.  Broke the tip off of the ampoule containing the COD test reagent, dichromate.

3.  Added 2mL of sample to the ampoule.

4.  Placed a blue cap on top, and swirled the ampoule which mixed the contents. 

5.  Placed the ampoule in the digestor block.

6.  Repeated steps 2-5 for each sample.

7.  Heated the ampoules for 2 hours at 150°C.

8.  Took the ampoules out of the digestor, and allowed to cool to room temperature. 

9.  Set the spectrophometer to 620nm.

10.  Used a blank to set the zero concentration point for the spectrophometer.

11.  Tested each ampoule in the spectrophometer, and recorded the results as percent transmittance. 

12.  Charted and graphed the results. 

Nutrients Tests

The three tests were conducted using LaMotte field testing kits.

Iron Test:

1.  Filled test tube [with the water] to the 5mL line.

2.  Added one Total Iron TesTab.

3.  Caped the tube and mixed until the tablet disintegrated.

4.  Waited 5-15 minutes. 

5.  Compared the color of the sample to the Iron Color Chart.  Recorded the results in ppm Iron.

Copper Test:

1.  Filled the test tube to the 10 mL line.

2.  Added one Total Iron TesTab.

3.  Caped the tube and mixed until tablet disintegrated.

4.  Compared the color of the sample to the Copper Color Chart.  Recorded the results in ppm Copper.

Ammonia Test:

1.  Filled the test tube to the 5mL line.

2.  Added on Ammonia #1 TesTab.

3.  Caped the tube and mixed until the tablet disintegrated.

4.  Added one Ammonia #2 TesTab.

5.  Caped the tube and mixed until the tablet disintegrated.

6.  Waited 5-15 minutes.

7.  Compared the color of the sample to the Ammonia Color Chart.  Recorded results in ppm Ammonia.

Both COD and Nutrients Tests:

Charted and graphed results on Excel.