Which depth is NOT recommended for soil sampling?

Which depth is NOT recommended for soil sampling?

• A. Top half-inch
• B. Quarter-inch
• C. Two inches
• D. Six inches

Answer: (B)

Choosing the right depth for soil sampling is about getting a representative picture of the soil people are exposed to, not just the very surface layer. A depth like a quarter-inch tends to capture only loose dust, surface coatings, and debris rather than the actual soil that children play in or roots interact with. That makes the results unreliable for assessing long-term contamination. In most standard soil-lead sampling protocols, you sample within the top several inches to represent the surface soil, and you also sample deeper (for example, around 6 inches) to understand subsoil conditions. The depths described as the top portion of the soil and deeper soil align with how people interact with soil and how lead tends to distribute within the soil profile, whereas a quarter-inch depth would not give a meaningful representation of soil contamination.

Choosing the right depth for soil sampling is about getting a representative picture of the soil people are exposed to, not just the very surface layer. A depth like a quarter-inch tends to capture only loose dust, surface coatings, and debris rather than the actual soil that children play in or roots interact with. That makes the results unreliable for assessing long-term contamination. In most standard soil-lead sampling protocols, you sample within the top several inches to represent the surface soil, and you also sample deeper (for example, around 6 inches) to understand subsoil conditions. The depths described as the top portion of the soil and deeper soil align with how people interact with soil and how lead tends to distribute within the soil profile, whereas a quarter-inch depth would not give a meaningful representation of soil contamination.