How Soil Gets Polluted
July 1st, 2009 | 
Soil is a sort of ecosystem unto itself, and it is relatively sensitive to foreign matter being applied to it. That’s good for us in the case of wanting to add soil amendments, fertilizer and compost to make the soil healthier, but not so good when it comes to soil pollution.
There are many different ways that soil can become polluted, such as:
- Seepage from a landfill
- Discharge of industrial waste into the soil
- Percolation of contaminated water into the soil
- Rupture of underground storage tanks
- Excess application of pesticides, herbicides or fertilizer
- Solid waste seepage
The most common chemicals involved in causing soil pollution are:
- Petroleum hydrocarbons
- Heavy metals
- Pesticides
- Solvents
Soil pollution happens when these chemicals adhere to the soil, either from being directly spilled onto the soil or through contact with soil that has already been contaminated.
As the world becomes more industrialized, the long term effects of soil pollution are becoming more of a problem all over the world. It is thought that a full 150 million miles of China’s farmland is contaminated.
Soil Pollution Problems
Even when soil is not being used for food, the matter of its contamination can be a health concern. This is especially so when that soil is found in parks, neighborhoods or other places where people spend time.
Health effects will be different depending on what kind of pollutant is in the soil. It can range from developmental problems (in children exposed to lead) to cancer (from chromium and some chemicals found in fertilizer, whether those chemicals are still used or have been banned but are still found in the soil).
Some soil contaminants increase the risk of leukemia, while others can lead to kidney damage, liver problems and changes in the central nervous system.
Those are just the long term effects of soil pollution. In the short term, exposure to chemicals in the soil can lead to headaches, nausea, fatigue and skin rashes at the site of exposure.
Environmental Long Term Effects of Soil Pollution
When it comes to the environment itself, the toll of contaminated soil is even more dire. Soil that has been contaminated should no longer be used to grow food, because the chemicals can leech into the food and harm people who eat it.
If contaminated soil is used to grow food, the land will usually produce lower yields than it would if it were not contaminated. This, in turn, can cause even more harm because a lack of plants on the soil will cause more erosion, spreading the contaminants onto land that might not have been tainted before.
In addition, the pollutants will change the makeup of the soil and the types of microorganisms that will live in it. If certain organisms die off in the area, the larger predator animals will also have to move away or die because they’ve lost their food supply. Thus it’s possible for soil pollution to change whole ecosystems.
Dealing with Soil Pollution
There are some ways to get soil back to its pristine condition or to remove the spoiled soil so the land can be used for agriculture again. Tainted soil can be transported to a site where humans won’t be exposed to the chemicals, or the soil can be aerated to remove some of the chemicals (which can add the problem of air pollution if the chemicals can be released into the air).
Other options include what’s known as bioremidiation, where microorganisms are used to consume the pollution-causing compounds as well as electromechanical systems for extracting chemicals, and containment of chemicals by paving over the tainted area.
None of these are an ideal solution. Preventing contamination in the first place is the best way to go. It won’t eliminate all potential pollution problems, but choosing to farm organically is a good way to protect the soil (and yourself) from chemicals found in pesticides and other common garden chemicals..
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