Lead loading refers to what measurement?

• A. It measures total lead dust on a surface
• B. It measures lead concentration in air
• C. It measures lead in soil
• D. It measures lead concentration in drinking water

Answer: (A)

Lead loading is the amount of lead dust that has settled on a surface, measured as micrograms of lead per square foot (µg/ft^2). This metric is used during clearance testing after lead abatement to confirm surfaces meet the required cleanliness thresholds, reflecting surface contamination from dust rather than anything in the air, soil, or drinking water. For context, air lead concentration is measured in micrograms per cubic meter (µg/m^3), soil lead content is typically reported as milligrams per kilogram (mg/kg), and drinking water lead concentration is given in micrograms per liter (µg/L). Sampling usually involves wiping a defined surface area and analyzing the collected dust in a lab.