The success of a garden or crop depends on the fertility of the soil and whether it is free of contaminates. Soils with low nutritional value will not grow good crops. A soil that has a high level of contaminates may grow food that is unsuitable for consumption. Petroleum in soil is the introduction of crude oil into the environment due to human activity. Oil spreads easily and is highly dangerous when it collects in large amounts. Testing for fuel contamination is one step in ensuring your soil is healthy.
Place a small spoon full of soil into a glass jar and fill the jar three-fourths of the way full with water. Shake the jar to disturb the soil and mix it with the water thoroughly.
Allow the soil to settle at the bottom of the jar. Let the jar sit for a couple of days until the cloudiness of the dirt is gone from the water.
Inspect the top of the water to determine whether there is a greasy layer at the top. Rainbows on the top of the water indicate a possible petroleum contamination. This indicates further tests are required.
Use a portable petroleum analyzer kit according to the instructions on the packaging to determine how much petroleum is present in the soil. Petroleum analyzing kits are available online.
Send your soil sample to a testing laboratory at your local university extension for further testing if your analysis is confusing or insufficient.