Almost all of lead in soil comes from lead-based paint chips flaking from homes, factory pollution, and from the use of leaded gasoline. Over time, lead builds up in soil. Lead levels in soil are usually higher in cities, near roadways and industries that use lead, and next to homes where crumbling lead paint has fallen into the soil.
The danger of the lead in soil depends on:
- the amount of lead in the soil around your house...
- and the amount of soil that gets into your child.
The amount of lead in soil is measured in parts per million (ppm). The greater the amount of lead in soil, the higher the ppm number. Soil naturally has small amounts of lead in it, about 50 ppm. 200-500 ppm of lead is commonly found in city soil. 1,000 ppm is a high amount of lead in soil, and is defined as hazardous waste.
Lead in dirt clings to fingers, toys and other objects that children normally put in their mouths. This is the most common way that lead in soil gets into your child. Lead in soil does not pass through unbroken skin. If soil is covered with plants, rocks or other ground cover, children have less contact with the dirt and the lead in it. The more lead that is in your soil, the more harmful the soil can be to your children's health.