Students' Water Samples Tested
by the Davenport Water Pollution Control Works

Students collect a surface water sample from Mississippi River from the shore of Credit Island.
What would you expect about the cleanness of the river?
A student collects a surface water samplethe same day at nearby Nahant Marsh, months after the EPA clean-up.
What would you expect about the cleanness of the marsh?

About Davenport Water Pollution Control Works

Students' Sample Data

Davenport Water Pollution Control Works is a neighbor of Nahant Marsh. This facility treats the city's wastewater, which comes to it via the sanitary and storm water sewer systems, and then discharges the cleaned water into the Mississippi River. It also contributes recycled, cleaned sludge to another marsh neighbor, the city's Compost Facility. For a description of the wastewater and composting processes, see "About Davenport Water Pollution Control Works".

To learn more about BOD, dissolved oxygen, and chemical testing, the U.S. government's Globe project has hands-on activities to help you practice the protocols. See enlargement of students' Nahant Marsh Sample 10/12/99, analyzed by the Davenport Water Pollution Control Works. What parameters (substances) are represented on the graphic? What technology is used to generate this report? What is a possible interpretation of the results? How can you find out if you are on the right track with your interpretation?

High school students visit Davenport Water Pollution Control Works on sampling day. The laboratory tested their river and marsh samples. See enlargement of students' Mississippi River Sample 10/12/99, analyzed by the Davenport Water Pollution Control Works. What parameters (substances) are represented on the graphic? What technology is used to generate this report? What is a possible interpretation of the results? How can you find out if you are on the right track with your interpretation?

Study the numeric data in relationship to the two line graphs above.
Then, research each parameter and evaluate whether the numeric data probably indicate a healthy situation or an unhealthy situation where the samples were taken. Be ready to support your views with reasons supported by science. (Note: For the purpose of this activity, assume the data are reliable for the spot where the samples were taken.)
Parameter Nahant Marsh Credit Island
(Mississippi River)
BOD 9.9 7.5
Dissolved Oxygen 6.73 9.06
PB 0.0052 0.0087
F 0.209 0.250
CL 43.33 14.99
NO2 ND (means nondetection) 0.056
NO3 0.129 4.657
PO4 0.075 0.224
SO4 74.24 24.75

Resources of Interest:

National Guidance Water Quality Standards for Wetlands:http://www.epa.gov/OWOW/wetlands/regs/quality.html
Water Quality Standards & Criteria (Purdue University): http://pasture.ecn.purdue.edu/~cttpp/programs/download/wqs.htm