Charlie is a 3-year-old in a community preschool. The staff reports that he tends to put everything in his mouth and is frequently found eating dirt. A home visit by a school staff member to discuss the problems with his parents reveals a generally clean environment in a very old home that was being renovated. Recently, Charlie has been falling behind in academic skills compared with the other children in his class; his linear growth has slowed, and he is tired and irritable. His physician noted pallor and what look like "pencil lines" on the gums adjacent to his teeth. He ordered blood tests, which revealed a low hemoglobin level and an elevated lead level.
Based on the patient history, signs and symptoms, and lab test results, discuss the probable environmental factors responsible for Charlie’s ingestion of lead. (See Heavy Metals—Lead.)