How many soil samples should be collected for one composite sample?

How many soil samples should be collected for one composite sample?

• A. Three to ten
• B. One to three
• C. Eleven to twenty
• D. Five to fifteen

Answer: (A)

When creating a composite soil sample, you mix several individual subsamples from the target area to capture variability in lead levels across that area. The goal is to represent the area well without unnecessary cost. Three to ten subsamples strikes a practical balance: enough spots to catch differences in contamination, but not so many that you waste time and money. If you take too few, you might miss higher-lead spots; taking more than ten for a single composite often isn’t needed and adds cost. In practice, define the area, collect subsamples from multiple evenly distributed spots at the appropriate depth, combine them in a clean container, mix thoroughly, and submit the single composite for analysis.

When creating a composite soil sample, you mix several individual subsamples from the target area to capture variability in lead levels across that area. The goal is to represent the area well without unnecessary cost. Three to ten subsamples strikes a practical balance: enough spots to catch differences in contamination, but not so many that you waste time and money. If you take too few, you might miss higher-lead spots; taking more than ten for a single composite often isn’t needed and adds cost. In practice, define the area, collect subsamples from multiple evenly distributed spots at the appropriate depth, combine them in a clean container, mix thoroughly, and submit the single composite for analysis.