Lead in surface dust and soil can come from?

• A. Heavy rainfall washing away dust
• B. Drinking water contamination only
• C. Weathering and chipping of lead-based paint and renovations that break painted surfaces
• D. Natural background soil with no human influence

Answer: (C)

Lead in surface dust and soil around homes mainly comes from deteriorating and disturbing lead-based paint. In older houses, paint that contains lead chips, cracks, and peels over time, turning into dust that settles on floors and other surfaces. When renovations or remodels break painted surfaces, they release large amounts of lead-containing dust and chips, which contaminate both indoor surfaces and surrounding soil. This pathway directly explains why indoor dust and adjacent soil become contaminated and why renovations are a major risk factor.

Other options describe ways dust might move or where lead can come from, but they don’t represent the primary source in most homes. Heavy rainfall can redistribute dust but doesn’t create new lead contamination; drinking water contamination involves a different exposure route, not surface dust or soil; and natural background soil may contain trace lead but is usually not the main contributor to a home’s lead-laden dust and soil compared with lead paint sources.