How deep should a soil sample be taken for lead assessment?

How deep should a soil sample be taken for lead assessment?

• A. 2 inches
• B. 1/2 inch
• C. 1 inch
• D. 3/4 inch

Answer: (B)

The main idea is to test the soil that children are most likely to contact and ingest. Lead contamination from exterior paint, dust, and settled pollutants tends to stay concentrated in the surface layer of soil. Sampling about one-half inch below the surface targets that exposed layer where exposure risk is highest, rather than digging deeper into subsoil that is less contaminated and could dilute the measured concentration. This shallow depth provides a more protective and representative assessment of what a child playing nearby could encounter. For a good assessment, collect multiple surface samples from different spots around the area and combine them to form a composite reading, but keep the depth at about one-half inch to reflect the most relevant exposure zone.

The main idea is to test the soil that children are most likely to contact and ingest. Lead contamination from exterior paint, dust, and settled pollutants tends to stay concentrated in the surface layer of soil. Sampling about one-half inch below the surface targets that exposed layer where exposure risk is highest, rather than digging deeper into subsoil that is less contaminated and could dilute the measured concentration. This shallow depth provides a more protective and representative assessment of what a child playing nearby could encounter. For a good assessment, collect multiple surface samples from different spots around the area and combine them to form a composite reading, but keep the depth at about one-half inch to reflect the most relevant exposure zone.