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Effect of 1940's Land Use On Arsenic Levels in The Soil Today

  The Experimenter
Researched by Amanda J.


The purpose of this experiment was to compare the effects of land use during the 1940’s the on arsenic level in the soil today.

I became interested in this idea when I became aware of the arsenic problem in our community.  I wondered how widespread arsenic contamination was and what caused it.

The information gained from this experiment would show parents and community leaders how much arsenic is in public school soil. This information might be used to encourage clean up or find ways to protect school children from exposure.


My hypothesis was that locations that were used during the 1940’s as orchards would have the most arsenic in the soil.

I based my hypothesis on a statement by Norm Hepner, a Washington State Department of Ecology engineer.  He said, “The Intermediate School is most likely the only school truly affected, though the results may prove this incorrect because the soil was moved to create the design of the campus.”


The constants in this study were:
  • Depth in the ground at sampling (15 cm.)
  • Amount of soil tested
  • Amount of samples per school
  • Testing equipment
  • Method of soil removal
  • Digging equipment
The manipulated variable was the location the samples were taken from.

The responding variable was the amount of arsenic in the soil samples.

To measure the responding variable I used an Innovox system loaned by the Washington State Department of Ecology.


    15       plastic bags
     1        Shovel
     1        garden rake
     1        Testing kit
     1        Black Permanent marking pen
     1        Measuring cup
     1        Innovox system


1.  Plan where to take samples
     a) Plot on a map of each school where to take samples
     b)  Repeat for every one of the three schools

2. Take samples at one location
     a) Dig a 15 cm. deep hole with a clean shovel at location one
     b) Remove 125 ml. of dirt from the bottom of the hole
     c) Put dirt in a plastic sandwich bag
     d) Label bag with school and location number

3. Repeat step 2 for every one of the three locations on campus

4. Repeat steps 2-3 for each school

5. Test the samples with a innovox system
     a) Place plastic sandwich bag on top of the metal plate
     b) Scroll down on the digital screen until you come to the symbol “As.”
     c) Record amount of arsenic in ppm. (Parts per million) in the sample on a data table
6. Repeat steps 5 for every sample in school one

7. Repeat steps 5-6 for every school

8. Analyze data


The original purpose of this experiment was to compare the effects of land use in 1940’s the on arsenic level in the soil today.

The results of the experiment were that Selah Intermediate School had on average 58.7 ppm. Of arsenic and it was the only school that was an orchard in the 1947.

See my table and graphs


My hypothesis was that locations that were used during the 1940’s as orchards would have the most arsenic in the soil.

The results indicate that this hypothesis should be accepted because Selah Intermediate School had the most arsenic and it was the only school that was an orchard in the 1940’s.

Because of the results of this experiment, I wonder if other school districts would have different amounts of arsenic, if other toxins were in the soil, and if the arsenic in the water affected the soil.

If I were to conduct this project again I would get the samples before the ground froze and I would test more schools and samples I would also test the samples more than once.


Soil is one of our most important resources.  We cannot survive without clean soil.  Since over 95% of our food comes from the soil one way or another, keeping soil clean so it remains healthy and productive is an important survival issue. If the soil on school playgrounds is contaminated with toxins and chemicals then children are at risk of minor to serious health issues.

Arsenic is a naturally occurring chemical element.  Pure arsenic is grayish and metal like, but is rarely found in nature. Arsenic is usually found combined with one or more other elements such as oxygen, chlorine, and sulfur. When arsenic is combined with these, arsenic is referred to as inorganic arsenic.  When arsenic is combined with carbon and hydrogen is referred to as organic arsenic. The organic forms are usually less toxic than the inorganic forms.
The atomic number for chemical arsenic is 33 the atomic weight is 74.9216 the symbol is “As.”

Certain ferns remove arsenic from soil they are planted in.  There are also testing and removal kits available.

Organic arsenics cannot cause cancer, or DNA damage, but exposure to high doses may cause certain effects to human health, such as nerve injury and stomachaches. Exposure to inorganic arsenics can cause a variety of health effects, such as less production of red and white blood cells, irritation of the stomach and intestines, skin changes and lung irritation. Large amounts of inorganic arsenic can increase the chances of cancer, especially the chances of skin cancer, lung cancer, liver cancer and lymphatic cancer. Plants absorb arsenic easily, so that high concentrations may be in the plant tissue. So if animals eat the plants, they ingest a great amount of arsenic. They will die as a result of poisoning. They decomposed into the soil where other animals live so the ground will be toxic. As a result plants grow and the cycle starts again.

The most common uses of arsenic in the U.S. are wood preservatives (74%), agricultural products (19%), glass (3%), nonferrous alloys (2%), and other uses

Soil pollution
Waste, and chemicals and many other things dumped and thrown out by the carelessness of humans can cause soil pollution.   Poisons like gasoline, deicer, weed killers, and pesticides can soak into the soil and pollute it so plants like grass cannot grow and develop properly.

Soil contamination results when chemical substances are either spilled or buried. Another source of soil contamination could be water that washes toxins from an area containing chemical substances and deposits the contamination in the soil as it flows through.

Toxins in the soil can hurt plants when they try to grow or they can and take up the toxic chemicals through their roots. Contaminants in the soil can harshly impact the health of animals and humans when they ingest, or touch contaminated soil, or when they eat plants or animals that have already been affected by soil contamination. Animals ingest and come into contact with contaminants when they burrow in contaminated soil. Humans ingest and come into contact with contaminants when they play in contaminated soil or dig in the soil as part of their work. Certain contaminants, when they contact our skin, are absorbed into our bodies.
 There are three general ways to cleaning up toxic soil.
1) Soil can be moved from the ground and be either treated or disposed
2) Soil can be left in the area and treated in place
3)  Soil can be left in the ground and contained to prevent the contamination from becoming more widespread and reaching plants, animals, or humans.

Arsenic is a toxic chemical element that is in our water and soil.   It is endangering the children of the world as a toxin in the soil they play in and in the water they drink. Soil pollution is an important factor to health because the toxins may be ingested and may cause serious damage.


“Arsenic,” Britannica Encyclopedia inc. 2003

Bentor, Yinon “Chemical - Arsenic” December 8, 2004

Busch, Marianna.   "Arsenic,” World Book Encyclopedia, 2004.

Chertow, Marian .R.    "Environmental Pollution” World Book Encyclopedia, 1998

Hepner, Norm personal interview

Johnston, Taylor .J.   "Soil” World Book Encyclopedia, 2003

“The Mineral Native Arsenic” Amethyst Galleries, Inc. December 8, 2004


I would like to thank the following people for helping make my project possible:
  • My mom for helping me get the samples in freezing weather
  • Mr. Newkirk for grading and correcting my project
  • Mrs. Helms for helping me with my graphs
  • Norm Hepner for helping test the samples and assisting me in almost everything


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