Pollutants in Soil

Types

• Soil pollutants are anything found in soil that can damage the plants or animals that rely on the nutrients within the ground to survive. There are many types of pollutants, and some of the biggest problems come from the decay and contamination of man-made items dumped in landfills.

  Some of these pollutants even find their way into the backyard soil through polluted rains. Other types of soil pollutants include a buildup of nutrients like nitrates from the over-application of fertilizer, heavy metals from smoke, smog, and vehicle emissions and contaminants released into the air, water and soil by any nearby factories or industry.

Causes

• Air and water pollution ultimately end up in the soil, washed there by rains and other types of moving water. Even landfills and industrial plants that may be miles away could be affecting the soil quality of flowerbeds and vegetable gardens.

  Another common cause of soil pollution is the application of a number of herbicides, insecticides and pesticides. While spraying grass and flower gardens to keep the weeds and bugs away might seem like an easy method of pest control, some commercial sprays contain not only foreign organic materials, but can also contain tars and other chemical compounds that can build up in the soil over time.

Consequences

• Some contaminants are not only held in the soil for long periods of time, they can also be absorbed into plants. When this occurs around flower gardens and trees, it can kill the plants either quickly or over a period of time.

  When vegetable gardens are planted in contaminated soil, there is also the chance that these dangerous materials will be absorbed into the plants and transferred to the fruits and vegetables destined for human consumption. A study by Cornell University suggests that 40 percent of the world's deaths are caused by some kind of pollution.

  Soil contaminants also put water at risk. Nearby ponds can be quickly contaminated, and for homes that get their water from a natural well or spring, this can be a major concern.

Solution

• What to do with contaminated soil is a question that has no easy answers. Depending on the chemical makeup of the pollutant and the severity of the contamination, there may be different recommendations for dealing with the site -- many local college extension offices perform soil tests to determine nutrient content and pollution and can give the best personalized advice.

  In some cases, it may be suggested to remove the layers of contaminated soil to expose lower layers, or to replace the soil with new, uncontaminated material. There are also methods of applying thermal energy and heat to an area to kill bacteria or microorganisms that can be polluting that area.