How can dust and soil become contaminated with lead?

Dust and soil can become contaminated with lead primarily through processes such as weathering and the deterioration of lead-based paint. Over time, lead-based paint, which was commonly used in homes built before 1978, can chip, peel, or disintegrate due to age and environmental factors. When this paint breaks down, it releases lead particles that become airborne or settle in dust and soil.

Additionally, lead can enter the environment through other means such as industrial emissions, the use of leaded gasoline in the past, or lead-containing products that are no longer in use. However, the direct weathering of old paint is a significant and well-documented source of lead contamination in residential settings.

Understanding this mechanism is crucial for lead prevention efforts, particularly in older homes where lead exposure is a risk. Thus, the correct choice reflects a primary means by which lead becomes a concern in everyday environments.