Pollution occurs when either solid or liquid toxic substances are mixed with naturally occurring soil. Poisonous chemicals either adhere to soil particles or become trapped between them. Heavy metal compounds are released into the air as small particles, which settle into the soil and cause health risks. Children are especially vulnerable to the health risks caused by soil pollution.
Sources of Pollution
Man-made chemical compounds leach into the soil from excessive use of synthetic pesticides, contaminated water, oil and fuel spills and from leftover manufacturing waste products. Underground storage tanks for petroleum are also a source of chemical leakage into the soil. Lead leaches into soil from car emissions and lead paint.
Methods of Transmission
Heavy metal contamination in soil seeps into underground water sources and pollutes drinking water. Lead contamination is transmitted through the air. “The greatest danger of lead toxicity from soil is direct consumption of lead-contaminated soil or dust,” according to a University of Minnesota Extension report on lead in home gardens. The most contaminated soils are near busy streets and older industrial centers.
The U.S. Environmental Protection Agency states that “contaminants in the soil can hurt plants when they attempt to grow in contaminated soil and take up the contamination through their roots." Soil containing heavy metal pollutants produces food with the same pollutants. Soil polluted with pesticides can cause birth defects, cancer and various kinds of nerve damage, especially in children, according to the EPA.
The EPA describes three general approaches to cleaning up contaminated soil: soil can be excavated from the ground and be either treated or disposed; soil can be left in the ground and treated in place; or soil can be left in the ground and contained to prevent the contamination from becoming more widespread and reaching plants, animals, or humans. Research is also being done on vegetative remediation, which uses trees and plants to decrease leaching of metals into the ground and reduce destructive soil erosion.
Home Garden Solutions
Keep soil in the home garden free from major contaminants by not using synthetic fertilizer and pesticide products. If the soil is already contaminated, remedy the situation by using homemade or commercial compost. The living microorganisms in organic matter (compost) have been found to transmute heavy metals, according to the EPA. Lead-contaminated soil is remedied by covering it or mixing it with healthy, non-lead contaminated soil.