As a natural element, lead does not break down in the environment. Once it has been dispersed, it remains in the environment until humans intervene to remove or at least contain it. Lead most often enters the human body by being swallowed. In cases of extreme exposure to lead-contaminated dust, the lead can enter the body through the respiratory system. Lead poisoning can only be diagnosed with a blood test.
Many pediatricians now test for lead levels during routine checkups for young children.
The dust settles on children's hands and toys. Remodeling a home can send large quantities of lead-contaminated dust into the house. Most of the lead in drinking water comes from household plumbing, not from the local water supply. Homes in which water is delivered in lead pipes or in copper pipes with lead solder are at highest risk. The lead level can only be determined by a certified laboratory.