Wabash River Pollution Study Near Bluffton, Indiana

Jennifer H., Hanna R., and Amy S.

Southern Wells High School

September 10, 2004



     The purpose of the experiment is to discover whether Bluffton creates a significant amount of pollution released into the Wabash River. Six samples of the Wabash River water were taken from 3 different locations for close observation of pollution. The goals of this experiment are to discover levels of possible pollution in the Wabash River in the Bluffton area, comprehend how industrialization affects the purity of natural water sources, and obtain results from the lab to understand how they relate to pollution problems in the environment. An ecology test kit will be used to test the pollution levels of the collected samples. Oxygen, potential hydrogen (pH), and nitrite/nitrate levels will be the focus of this experiment.





     Will there be pollution before, in, or after Bluffton in the Wabash River? Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. This proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water. Pollution is also caused when silk and other suspended solids, such as soil, washoff plowed fields, construction and logging sites, urban areas, and eroded riverbanks when it rains. Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water (

     Oxygen is a nonmetallic element constituting 21% of the atmosphere by volume that occurs as a diatomic gas. It combines with most elements, is essential for plant and animal respiration, and is required for nearly all combustion. The two main sources of dissolved oxygen in stream water are the atmosphere and aquatic plants. Aquatic plants introduce oxygen into stream water as a byproduct of photosynthesis. The amount of oxygen that can dissolve in water is limited by physical conditions such as temperature and atmospheric pressure (, 2004). 

     The solubility of oxygen is greater in colder water than in warm water. Oxygen slips into “pockets” that exist in the loose hydrogen-bonded network of water molecules without forcing them apart. The oxygen is then caged by water molecules, which weakly pin it in place (, 2004).

     The dissolved oxygen level is an indication of how polluted the water is and how well the water can support aquatic plant and animal life. A higher dissolved oxygen level indicates better water quality. If dissolved oxygen levels are too low organisms may not be able to survive. Much of the dissolved oxygen in water comes from oxygen in the air that has dissolved in the water.  Some of the dissolved oxygen in water is a result of photosynthesis of aquatic plants. Water temperature also can affect dissolved oxygen levels. The higher the temperature, the less oxygen can dissolve in water (, 2004).

     A pH must be measured at the test site immediately because temperature affects pH value greatly (, 2004). A pH is a number used by scientists to indicate the concentration of hydrogen ions in a solution. A pH stands for potential hydrogen. A pH generally ranges from 0 to 14. A pH below 7.0 indicates that a solution is acidic, and a pH above 7.0 indicates that a solution is basic (alkaline). A pH is measured with an electronic pH meter or with special dyes called acid-base indicators (Rock, 2000).

     A pH measures the relative acidity of the water. A pH level of 7.0 indicates that solution is neutral. Pure water contains a pH level of 7.0. A pH reading between 6.5-7.5 is considered to be excellent, but if water’s pH level is less than 5.5 is very acidic and it is impossible for fish and other organisms to survive in the water. In the U.S., the pH of natural water is usually between 6.5 and 8.5. Acids are formed when emitted nitrogen oxides and sulfur oxides from the industries and motor vehicles combine with water vapor in the atmosphere. These acids cause rain to be acidic. Acid rain damages the environment in many areas (, 2004).

     The effects of water pollution by acid rain are varied. They include poisonous drinking water, poisonous food for animals, unbalanced river and lake ecosystems, and deforestation. Acid rain damages trees, crops, and buildings also. These effects are specific to the various contaminants (, 2004).

     Nitrates/nitrates are nitrogen-oxygen chemical units, which combine with various organic and inorganic compounds. The body converts nitrates into nitrates and disposes of them primarily through urination (, 2004).

     Most nitrogenous materials in natural waters tend to be converted to nitrate. All sources of combined nitrogen, particularly organic nitrogen and ammonia, should be considered as potential nitrate sources. Primary sources of nitrates include human sewage and livestock manure.  When nitrates are released into the environment, they tend to migrate to ground water.  They do not evaporate and therefore remain present until consumed by plants or other organisms (, 2004).

     In 1974, Congress passed the Safe Drinking Water Act. The Environmental Protection Agency is required to determine safe levels of certain chemicals in drinking water. Nitrates and nitrites are included in the chemical selection to be monitored due to possible health risks and exposure. The limit permitted by the EPA for nitrates is set at 10 parts per million, and the nitrite level is set at 1 part per million. These limits are known as maximum containment level goals (, 2004). 

     Excessive levels of nitrates in drinking water may cause many health effects. Young children may experience a shortness of breath and blueness of skin, which is caused by the chemicals interfering with the blood’s ability to carry oxygen. Long-term effects may include diuresis, increased starchy deposits, and hemorrhaging of the spleen (, 2004).

     The hypothesis is that there with be acceptable levels of dissolved oxygen and pH, with very little registering of nitrates/nitrites. This hypothesis was conceived due to regulations set and monitored by the EPA.  



Water samples from the Wabash River at the three locations

Ecology test kit (dissolved oxygen, pH meter, and nitrate/nitrite)  

500 mL plastic cup

String (enough to span from the top of the bridge to the river)

Weight (optional for sinking the cup so it will fill with the water)



Computer (to type the lab and gather information)



     Before beginning the lab gather all of the required materials.  Learn to use the kits by first practicing with samples of any water.  Make sure that all participants understand how to accomplish the tests so that the water samples can be tested at the river, because some tests can be affected by time. Three different tests will be performed at the Gerber Bridge, the Crosbie Bridge, and the White Bridge.  The levels of dissolved oxygen, pH, and nitrates/nitrites will be the focus of the lab. Follow the entire procedure for each area of the river being tested.  

Part 1: Collecting the Water Samples

In this part of the lab, a sample of water will be collected from the Wabash River.

1. Tie the weight to the 500 mL plastic cup very tightly with the string.  Be sure to have plenty of excess string, which the experimenter can hold onto while the sample is being taken. 

2. Place the cup and weight into the river, while still holding onto the attached string, and let the cup fill with water.  Then retrieve the filled cup by gently drawing in the string.

Part 2: Testing the Water Samples

In this part of the lab, the collected water sample is tested for pollution indicators in the form of pH, nitrate/nitrite levels, and dissolved oxygen.

     Water testing for levels of pH. The pH level was tested first due to its relationship with temperature. A pH meter was placed directly into the water and the result was recorded.

     Water testing for nitrate/nitrite levels. Nitrate/nitrite levels were indicated by using specific nitrate/nitrite test strips. The strip was placed into the water for approximately 2 seconds, then laid flat for 30 seconds.  Results were then compared to the color chart.

     Water testing for dissolved oxygen. The ecology test kit comes with all necessary materials to test for dissolved oxygen levels. The glass bottle was rinsed three times with the water sample and filled to overflow. The stopper was then inserted to the glass bottle to ensure that a small part of the sample spills over. Next, remove the stopper. Add 5 drops of both Manganous Sulphate Solution and Alkali-Azide Reagent to the sample. Add more of the water sample so that the bottle is completely filled. Replace the stopper into the bottle to ensure that no air bubbles are trapped in the bottle. Invert the bottle several times. The sample will become orange-yellow and a flocculent precipitate will form if oxygen is present. Let the sample stand; the flocculent precipitate will start to settle. Approximately 2 minutes later, when the upper half of the bottle becomes limpid, add 10 drops of Sulphuric Acid Solution. Again replace the stopper into the bottle and invert it until all particulate material is dissolved. The sample will be ready for measurement when it becomes yellow and completely limpid. Remove the cap from the plastic vessel. Rinse the plastic vessel with the water sample, and then fill it to the 5 mL mark and replace the cap. Add 1 drop of Starch Indicator through the hole in the cap and swirl it carefully. The solution will then change to a violet or blue color. Push and twist pipet tip onto the tapered end of the syringe ensuring an air tight-fit. Take the titration syringe and push the plunger completely into the syringe. Inset tip into HI 3810-0 Titrant solution and pull the plunger seal to the 0 mL mark of the syringe. Place the syringe tip into the cap hole of the plastic vessel and slowly add the titration solution. After each drop, swirl the plastic vessel to mix the solution. Continue adding the titration solution until the solution in the plastic vessel changes from a violet or blue color to a colorless composition. Read the milliliters of the titration solution from the syringe scale and multiply the reading by 10 to obtain a mg/L (ppm) oxygen level. If the results are lower than 5 mg/L, the test precision can be improved by adding more of the unused sample into the glass bottle to the 10 mL mark of the plastic vessel. Proceed with the test as described before and multiply the values on the syringe scale by 5 to obtain a mg/L dissolved oxygen level. Record the final results.




       The first sample was taken at the Gerber Bridge, north of Bluffton. This sample was tested on site for the mentioned substances. The water sample contained 6.7 mg/L of dissolved oxygen. The sample read 8.4 on the pH meter, and registered less than 1 part per million when tested for nitrates/nitrates.

     The next sample, taken at the Crosbie Bridge, center of Bluffton, contained 7.4 mg/L of dissolved oxygen. The pH level was found to be an 8.0, and the nitrate/nitrite test strip showed the present level of nitrates/nitrites to be less than 1 part per million.

     The final sample of water was taken from the White Bridge, southeast of Bluffton. The dissolved oxygen level reached a level of 6.5 mg/L, while the pH level dropped to a reading of 7.9. The nitrate/nitrite level remained at a level of less than 1 part per million. Dissolved oxygen level should be around 10 mg/L; the standard reading of pH should be between 6.5-8.5; nitrates/nitrites readings ideally register less than 1 parts per million (see Graph).


     Will there be pollution before, in, or after Bluffton in the Wabash River? The hypothesis was that there would be acceptable levels of dissolved oxygen and pH, with very little registering nitrates/nitrites. The hypothesis was supported. One unforeseen problem in the conduction of the lab was that the readings are altered by time. New samples had to be taken and tested on site. The pipet calibration caused some difficulties related to reading of left over amounts of the reagent. An improvement to the lab would be timing.  The lab would be ideal to perform in the spring when farmers are fertilizing the surrounding fields. Would studying the forms of wildlife surrounding and inhabiting the Wabash indicate high pollution levels?









Carbon Dioxide Test Kit. (2004). Directions used to test the oxygen in water. [Brochure]. Hanna Instruments.

Consumer Factsheet on: Nitrates/Nitrites. Retrieved September 3, 2004, from


Definition of dissolved oxygen. Retrieved September 3, 2004, from 


How to predict oxygen solubility in water.  Retrieved September 3, 2004, from

Information on pH and pH testing. Retrieved September 3, 2004, from


The effects of water pollution and how to decrease problems with pollution. Retrieved

September 3, 2004, from







Figure Caption

Figure 1. This representation shows how much pH, nitrites/nitrates, and dissolved oxygen was found in the Wabash River at 3 different locations around Bluffton. The EPA standard levels of pH, nitrites/nitrates, and dissolved oxygen are represented also.






                                                                                                *ppm represents less than 1% if value is 0


EPA Standard/Means: pH ~7.5, Nitrate/Nitrite ~less than 1%, DO ~10mg/L