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Absorption of Pollutants in Different Soil Types.

Researched by Audra S.


The purpose of this experiment was to determine which polypedon  (type of soil) was most absorbent of liquid pollutants.

I became interested in this idea when I was playing in a creek near my Grandma's house.  I noticed that the soil around the creek was darker and smelled funny. I moved several rocks that also smelled strange on the bottoms to find soil saturated in oil.  I thought that if the oil had drifted downstream then the entire creek banks would be polluted. I then wondered that if the soil around the creek banks were less absorbent if they would be less polluted.

The information gained from this experiment will benefit farmers, gardeners and botanists who have soil pollution problems to better understand absorbency in different types of soil.


My first hypothesis was that the soil with less porosity would be most absorbent. 

My second hypothesis was that the more viscous pollutant would be most absorbent.

I based my first hypothesis on the fact that soil with less porosity will have less room for liquids to fill, making the soil allow liquids to sit on top for a period of time.

I based my second hypothesis on Troy Slobig's statement, which was "Since oil is thicker than gas and antifreeze, it should be absorbed the most." 


The constants in this study were:

  • The filter used
  • Amount of pollutants (250 ml)
  • Amount of soil filtered (250 mg)
  • Number of trials on 1 soil type with 1 kind of pollutant (3)
  • Temperature of pollutants (21°C )
The manipulated variable was the type of soil filtered and the kind of pollutant being filtered. Each kind of soil (silt, sand, loam and clay) filtered each kind of pollutant (oil, gas and antifreeze) three times.

The responding variable was the amount of pollutants that filtered through the 250 mg of soil. 

To measure the responding variable I used a graduated cylinder mL.

Plastic Filter
750mL Sand, Clay
750mL Oil, Gasoline, Antifreeze
30 (16oz) plastic cups
500mL Graduated Cylinder
1 Scratch Paper
Organized Table
Stop Watch or watch with a second hand 


1.) Create a clean and organized area near a working sink or tub of water.
2.) Place 1 plastic cup on the table.
3.) Set filter in the cup so it is sturdy.
4.) Carefully put 250mg of soil 1 in filter.
5.) Accurately measure 250mL of oil in a graduated cylinder.
6.) Pour oil onto soil 1 slowly and steadily.
7.) Once oil is completely out of the cylinder begin timing filtering for 60 seconds with the stopwatch.
8.) After the 60 seconds are completed, immediately remove filter from the cup and set it in the sink. Immediately clean up any spills if you have any.
9.) Once the filter is in the sink pour the remaining oil in the cup, into the graduated cylinder. Record the amount on the piece of scratch paper, but this is not your final measurement.
10.) On the same paper as the recorded measurement, write the following equation: 250 - pollutants remaining = pollutants absorbed, and solve it by filling in the numbers where the variables are.
11.) Record the difference to the equation in step 10 on the organized table.
12.) Repeat steps 1-11 two times with the same pollutant and the same soil.
13.) Repeat steps 1-11 three times with the same pollutant and soil 2.
14.)  Repeat steps 1-11 three times with gasoline and soils 1 and 2.
15.) Repeat steps 1-11 three times with antifreeze and soils 1 and 2.


The original purpose of this experiment was to determine which polyp don  (type of soil) was most absorbent of liquid pollutants.

The results of the experiment were that the oil and clay combination was the most absorbent as I suspected, but some oil just sat on the top because it was so thick. The clay absorbed an average of 220.33mL of oil, 112.33mL of antifreeze, and 132.33mL of gasoline. The sand absorbed an average of 126mL of oil, 146.33mL of antifreeze and 138mL of gasoline. I noticed that the antifreeze and gasoline ran right through both soils quickly because they were both thin, like water. 

See the table and graph.


My first hypothesis was that the soil with less porosity would be most absorbent. 

My second hypothesis was that the more viscous pollutant would be most absorbent.

The results indicate that my first hypothesis should be accepted.

The results also indicate that my second hypothesis should be accepted.

Because of the results of this experiment, I wonder if the moisture of the soil affected its ability to drain and absorb liquids.

If I were to conduct this project again I would use a wider variety of pollutants and kinds of soil, more accurately measure my data with more accurate tools, do more trials on the experiment and follow my procedures more closely and accurately.

Day by day, we are connected to soil directly or indirectly with almost everything we use. When we walk into a building, the ground is holding it up. Vegetables and fruits we eat gain nutrients from soil that are fed to the plant through its roots. Animals that eat the healthy plants for nutrients give us nutrients. Sadly, because soil is created slowly and easily destroyed, it is commonly polluted in areas near heavy traffic, large cities and dumping sites. Since more pollutants are accidentally or unintentionally spilled, prevention is more important.

Soil (as stated above) is created slowly and destroyed easily. Soil is mainly made up of rock debris and organic materials, such as decomposed plants and animals. Microbes that live in the soil, cause dead organisms to decay to help return nutrients to the soil. Soil is made up of organic and mineral particles.

Water and air fill in spaces between the particles of organic and mineral matter. Animals and insects fill in the air filled spaces. These spaces are called pore spaces, and because different soils have different contents and pore spaces, the contents in soil constantly change. Plants' roots also grow in pore spaces, but usually in water filled pore spaces.

The food chain basically begins with soil or water. An example would be that a plant seed falls off of a dying bean plant and lands onto a soil bare patch. The wind begins to blow and the topsoil blows onto the seed, burying it slightly. A large fox runs onto the bare patch, pressing the seed firmly into the ground. That month, heavy rains fall and the seed starts to sprout roots. After several months the seed becomes a producing plant. A small pheasant drifts down to the bean plant and plucks several large nutritious beans and swallows them, repeating this until he's full. As the bloated pheasant glides off back to a nearby tree, hunters shoot the pheasant down and carry their prize off to be prepared for dinner. Soon, winter approaches and the dying plant drops another seed and starts the cycle over again.

The main purpose for soil is as a base for structures. Even the cement and pavement we walk on is supported by soil underneath. Also, soil is crucial for farming and gardening. We even use soil to build some of our homes, buildings and furniture framing, directly and directly. Bricks are usually made from a clay soil and cement mixture and trees grow in soil, while we use them for the sub framing of buildings, houses and furnishings such as couches and chairs. Also we use wood for home weather proof out door siding, flooring, etc... We even use wood for fuel in wooden fires.

There aren't really specific kinds of soil, due to the fact that every soil is different. The difference may be texture, color, porosity or content of the soil, but no soil is exactly alike. Yet, pedologists’ use the term "polypedon" to classify soils into a family, such as you would to animals, by the similarities between two soils. Clay, silt, sand and loam are few of the soils that scientists base classifications.

Pollution is a daily problem and hazard to the human race as well as all other things on earth, living or not. Water, air and soil pollution is constant and deadly to all organisms that come to inhabit on, in or near a toxic area of pollutants. Even as we try to reduce the amount of litter, smoke, pollution and excess carbon dioxide, we will never be able to save all that we as humans have damaged in the many years past. Yet, knowing the causes could lead to solutions.

Every average human usually has one or more vehicles of transportation, namely, a car. And every day more and more cars are built and destroyed. As each car is destroyed or totaled in an accident, the fuels and gasses and pollutants that once were the main "juices" of the car are now just deadly toxins leaking into a nearby stream, field or water tank, eventually contaminating any thing that comes intact with it. Also ships, airplanes, jets, shuttles and any thing that emits a toxic fume or gas contributes to the massive amount of pollution on planet earth.

Non degradable compounds like DDT, dioxins, PCB’s and radioactive materials can reach dangerous levels of accumulation as they are passed through the food chain (as stated above) into the bodies of larger animals. An example would be that an oil spill occurs in the Atlantic Ocean from a crashed speed boat. The oil from the boat sinks to the bottom of the ocean floor, contaminating the aquatic plants growing there. A small fish that grazes on those plants consumes a high concentration of the toxin. Soon a larger fish or other predator that will eat the small fish will accumulate an even greater or even life-threatening compound of the pollutant.

From 1906 to 1962 about 3400 cattle dipping vats were constructed for the purpose of eradicating the tick responsible for transmitting the "southern cattle fever" disease, in Florida. The concrete vats were preferred due to their thoroughness, speed and simplicity. When the solution was disposed it was done in two ways. The first way was running it into a nearby pit where it will eventually seep into the ground. The second way was precipitating the arsenic out of the solution with iron solution plus quicklime, and then burying the left over sludge in a pit, resulting in arsenic pollution in the soil.( 


Castagno M., Joseph. The New Book of Popular Science. Danbury, Connecticut.

Philip Friedman. p. 106

Engelking, Paul. "Pollution." 2000.

Johnston, Taylor J. "Soil." The World Book Encyclopedia. 1999.

"Soil." Microsoft Encarta Encyclopedia. 2001.

Waddill, Christine Taylor. "Arsenic Contamination From Cattle-Dipping Vats". 
     March 1999  <> 

" Water Pollution." Microsoft Encarta Encyclopedia. 2001.

Winckler, Suzanne and Rodgers, Mary M. SOIL, Our Endangered Planet.
     Learner Publications Company, Minneapolis. 1994. pp. 5-65. 



I would like to thank:

  • My mom and dad for helping me to complete my project by driving me places and lending me the supplies I used.
  • My science teacher, Mr. Newkirk, because he let me use the supplies to do my experiment with complete accuracy.
  • My self for working so hard on my project and modivating myself to finish the best that I can.
  • Mrs. Helmes because she gave me encouargement to do the best that I could do. 

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