A Study of Claridy Creek: Water Pollution and the Effects of Phytoremediation on Contaminants

Part of the Young Naturalist Awards Curriculum Collection.

by Kyle, Grade 8, Oklahoma - 2006 YNA Winner
The abandoned Sunray Refinery complex with various low flat buildings and industrial stacks, on a paved lot with sections of green grass.
The abandoned Sunray Refinery

Once a bustling refinery, now a desolate wasteland, the Sunray Refinery is an abandoned Superfund site in Meridian, Oklahoma. For years I have driven by the old tanks and tall stacks of the old refinery. I began to wonder if any petroleum products or hydrocarbons were seeping into Claridy Creek behind the Sunray Refinery. Claridy Creek runs downstream through the town of Duncan, past the refinery, through the town of Meridian, and then into the town of Comanche. I've seen people fishing and walking in the creek. Cows drink from this water. The people of Meridian drink from wells that share the same groundwater with the creek. I wanted to discover if the refinery had contaminated Claridy Creek.

I started my field journal in June 2004. My dad and I got permission to walk on the land that bordered the refinery. I wanted to get close to where the refinery waste ran into the creek so that I could get a sample of the water.

June 7, 2004: As I walk behind the old Sunray Refinery, I smell petroleum and feel the gooey soil on my shoes. I pick up the soil, and it seeps through my hands as black sludge. The soil has been devastated by years of contamination from petroleum products and caustic chemicals. As I climb down the banks of the creek, I notice that the water smells strongly of petroleum. I fill my containers with the creek water and head home. 

Using a colormetric test kit, I tested the water for: ammonia nitrogen, pH, chlorine, chromium, copper, cyanide, iron, nitrate nitrogen, phosphorus, silica, and sulfide. The water tested negative for everything except nitrate nitrogen, phosphorus, and silica. These results did not show whether Claridy Creek was contaminated with petroleum. Since the water smelled strongly of petroleum, I needed to test it for hydrocarbons. While searching on the Internet for chemical testing kits, I found a lab in Maine where the chemists answered questions. A senior chemist, Mr. Curlett, wrote me back saying that he would test the water for hydrocarbons. He also answered many of my questions when I e-mailed him.

A person crouched at the rocky edge of a shallow body of water.
Kyle taking a water sample

December 6, 2004: Once again I'm walking along the creek behind the refinery. It's cool and windy today. I just took samples from three places: downstream from the refinery, behind the refinery, and upstream from the refinery. We have had a lot of rain lately and the water level in the creek is up. The water doesn't smell as bad as it did this summer.

When I got the samples home, I put the water in six special glass vials that would be sent to Maine. I could not use any plastic because plastic contains hydrocarbons that would contaminate the samples. I sent the vials in a special cooler so that the samples would not get too hot in Oklahoma, or too cold in Maine. I also conducted my own tests on the water. My results showed that the water behind and upstream from the refinery was high in nitrates and phosphates.
When testing the water, Mr. Curlett extracted and analyzed the semi-volatile portion, the portion that would be diesel and motor oil, using gas chromatography coupled with mass spectometry. The results were not what I expected. The creek water I sent to Maine did not have detectable amounts of hydrocarbons in it. But why did the creek water smell like petroleum?

Next, I tested the oxygen levels behind the refinery, and upstream and downstream from it. The oxygen levels at each site were high. The smell was not from anaerobic decomposition. Going back to the sites, I tested the creek water with lead acetate paper strips, and the results were negative. The smell was not from hydrogen sulfide.

After compiling my data, I concluded that the smell in Claridy Creek behind the refinery is coming from undetectable traces of hydrocarbons. Since the late 1990's steps have been taken to stop the leakage of hydrocarbons and hazardous substances into Claridy Creek. While my tests were negative, I still believe I can smell the petroleum even though it cannot be detected by the tests I performed. I continued to investigate Claridy Creek.

In previous tests, I had found high levels of phosphates and nitrates upstream from the refinery. I wondered how this could be. To my surprise, I discovered that the Duncan Wastewater Treatment Plant is upstream from the refinery. I continued testing Claridy Creek further upstream from the refinery, above the treatment plant.

January 10, 2005: Today I am testing upstream and downstream from the Duncan Wastewater Treatment Plant. It is hard to walk up and down the creek banks at this point, so I attach a bucket to a rope and drop it off the side of the bridge at Cherokee Road, upstream from the treatment plant. This is the method I used to take my samples downstream from the treatment plant as well. I collect my samples and take them home to test.

A chart titled, "Nitrate and Phosphate Levels in Claridy Creek."
Chart: Nitrate and Phosphate Levels in Claridy Creek (Click to enlarge)

My tests were conclusive, showing no levels of nitrates and phosphates above the treatment plant, but high levels in the creek downstream from the plant. Nitrates and phosphates are by-products of treating wastewater. The treatment plant uses a denitrification process to take out nitrates before the water is discharged back into the creek. Even though the water has been treated, high levels of nitrates and phosphates remain in it, contaminating the creek. Was there a way to remedy this?

August 30: As I look over the bridge down into Claridy Creek, I see the treatment plant to my north and the old refinery to my south. There are plants and grasses growing around and in the creek. I wonder if any of them help absorb the contaminants from the creek.

I started studying the refinery as a seventh grader. I began my second year of research as an eighth grader, trying to determine how I could naturally, efficiently, and inexpensively remediate the contaminated creek water. I turned my studies toward phytoremediation.

Boy studying water pollution in a greenhouse lab
Kyle in the greenhouse

While searching the Internet for more information on plants used in phytoremediation, I found an article written by Michael Russelle. He is a soil scientist for the United States Department of Agriculture, in the Agriculture Research Service, and he works at the University of Minnesota. He answered my e-mails about possible plants to use, and advised me during my experiments.

My dad and I built a greenhouse to store all of my plants and to conduct my experiments. I decided I would use cattails as my first phytoremediator. Cattails can survive the Oklahoma heat and thrive just about anywhere.

November 9, 2005: It is cool today, I found some cattails at my Grandma's pond and dragged them out of the water. I put them in five-gallon containers and took them home to my greenhouse.

I think that I am the only person alive who has actually killed a cattail. My cattails did not survive life in the greenhouse. This was definitely a setback because it was getting cold and soon all of the aquatic plants would be going dormant. Luckily, a local water gardener gave me some umbrella plants, another species of plant that can live in water. Also, Mr. Blauch, my science teacher's husband, let me pick some water plants from his backyard water garden. I then transplanted the umbrella plants, cattails and mint plants in my greenhouse, hoping they would live.

A plant specimen in a plastic container perforated with two holes to allow plastic tubes to lead to another plastic container.
Umbrella plants in water circulator

In my first experiment, I created a contraption to pump water back and forth from a 55-gallon barrel to an 18-gallon container. I mixed together fertilizer and water to simulate the high nitrate and phosphate content of Claridy Creek, and put the mix into the containers and into a control. At the beginning and end of the experiment, I tested the water for nitrates and phosphates using my chemical testing kit, and also sent samples to the OSU Lab for testing. I placed my umbrella plants in the 18-gallon container. I circulated the water every day by pumping water from the barrel to the plants, and kept records of the temperature in the greenhouse and the growth of the plants. I conducted my own water tests periodically during the experiment.

By the end of my first experiment, the umbrella plants had grown many new stalks, gotten much greener, and were thriving, but nitrate and phosphate levels increased in both the plant water and the control water. There was a high amount of algae in the water, which may have affected both nitrate and phosphate absorption. I think that possibly the fertilizer collected in the bottom of the 55-gallon barrel, and the pumping back and forth affected my results.

In my second experiment, I used mint plants and cattails, and mixed a greater concentration of fertilizer into the water. By the end of the experiment, both plants were turning brown, smelling very swampy, and generally not thriving. The level of nitrates in the mint plants' water decreased greatly, yet the level of phosphates remained high. The opposite occurred in the cattail water. While the phosphates remained the same, the nitrates increased. The nitrates showed a slight increase in the control water. My mint plants were a success! Now I wanted to test phytoremediation using actual creek water.

January 10, 2006: It is cold today. Even though we are in a drought there have been quite a few freezes. I walk down the creek bank south of the treatment plant, get a bucketful of water, and head back to the truck. I have to get a few more bucketfuls so I can conduct my experiment. I want this experiment to be authentic, so I'm using actual water from the contaminated creek.

A bar chart comparing nitrate levels in Claridy Creek water to control sample water.
Chart: Nitrate Levels in Plant Samples (Click to enlarge)

In this experiment, I wanted to determine if my umbrella plants would absorb nitrates into their roots and stalks. To do this, I put plants into water that had not been treated, well water, and water from Claridy Creek. I tested the water at the beginning and end of the experiment with my test kit, and Dr. Daniel, at the USDA-ARS Grazing Lands Research Laboratory in El Reno, tested both my water and my plant samples. The nitrates decreased in both water samples with plants in them, yet the total phosphates increased in each sample. The results showed that the plant stalks in the Claridy Creek water had more nitrates in them than the plants in the well water did. I concluded that my umbrella plants actually absorbed nitrates out of the water into their stalks. I had success!

I started my research studying the Sunray Refinery, moved to the Duncan Wastewater Treatment Plant, and then to phytoremediation. I found that the treatment plant was contaminating Claridy Creek with nitrate nitrogen and phosphorus, and that umbrella plants and mint plants will absorb nitrate nitrogen. Next year I would like to continue to study how the refinery is contaminating Claridy Creek. I would also like to continue to use my plants to remediate other contaminates, such as lead and arsenic.



Anaerobic Decomposition. Retrieved from the World Wide Web on 25 January 2005.

"County buys derelict refinery." Duncan Banner 29 August 2004: A1.

Curlett, James. E-mail correspondence/interviews by Kyle Ressel. 23 May 2004 to 19 January 2005.

Elias, Paul. "At contaminated sites, plants do the dirty work." The Providence Journal 26 July 2005: F2.

Fowler, Veronica, and Jamie Beyer. All About Garden Ponds. Iowa: Meredith Books, 1999.

Gas Chromatography . Retrieved from the World Wide Web on 1 February 2005.
http://unsolved mysteries.oregonstate.edu/GCMS 05.html

Greenhouses. Iowa: Meredith Books, 2002.

On-Site Wastewater Treatment Systems Manual. U.S. Environmental Protection Agency. February 2002.

Phytoremediation. Ecological Engineering Group. Retrieved from the World Wide Web on 8 August 2005.

Quinn, Vickie. "Forum focuses on refinery."  The Duncan Banner  14 November 2004: A1.

Risk-Based Cleanup Levels Total Petroleum Hydrocarbons . Department of Environmental Quality Fact Sheet. Retrieved from the World Wide Web on 14 December 2004.

Robertson, Stephen. "Refining plans."  The Duncan Banner  14 November 2004: A1.

Russelle, Michael. E-mail correspondence/interview by Kyle Ressel. 22 October 2005 to 6 April 2006.

Russelle, Michael.  Phytofiltration Shows Great Promise to Reduce Ground Water Nitrate.  Retrieved from the World Wide Web on 22 October 2005.

United States Court of Appeals Tenth Circuit Tosco Corporation, Plaintiff v.Koch Industries . 2 May 2000. Retrieved from the World Wide Web on 5 September 2004.