occurs everyday. It happens when a hazardous solid or liquid substance mixes with the natually occurring soil.
In most cases, the contaminants are attached to the soil either physically or chemically. Sometimes they are trapped
in between the particles of the soil. The contaminants usually come into contact with the soil by one of two ways, they
are either spilled into the soil or the are buried in the soil directly.
One of the most common substances spilled
into soil is oil. It often gets into the soil by leaking out of tanks, being spilled in the transportation process,
during loading/unloading, and leaks from pipelines. The severity of the contamination depends on the type of oil
involved. The heavier the oil, the slower it is able to spread. However, if a light oil is involved, it is able
to seep through the top soil quite quickly. It then continues to move quickly through the layers of soil. The faster
the cleanup crews responsd to the spill/leak, the better the chance of stopping the spread of the contamination before it
reaches the groundwater. Once it reaches the groundwater, the cleanup task is greatly increased because it is very easy
for the contamination to move through the groundwater.
|Fuel Puddle in Soil
|Click on the image to view its original source with information on the leak
Some factors affecting soil contamination due
to oil tank leaks are: the age of the tank, the quality of the installation job, and moisture content of the soil.
If the soil is wet, such as clay, it will increase the rate at which the tank rusts.