How many wipes for a composite sample?

How many wipes for a composite sample?

• A. 1-2
• B. 3-5
• C. 4-6
• D. 2-4

Answer: (D)

Composite sampling combines several wipe samples into one to get an average measure of lead contamination over an area. The number of wipes in a composite is chosen to balance representing variability on the surface with keeping the sample practical for lab analysis. Two to four wipes per composite provides enough coverage to catch hotspots without overly diluting the sample or making handling and analysis unwieldy. Using only one wipe risks missing contamination; using more than four can complicate processing and interpretation. If the area is large or highly variable, you can create additional composites, but a single composite typically uses two to four wipes.

Composite sampling combines several wipe samples into one to get an average measure of lead contamination over an area. The number of wipes in a composite is chosen to balance representing variability on the surface with keeping the sample practical for lab analysis. Two to four wipes per composite provides enough coverage to catch hotspots without overly diluting the sample or making handling and analysis unwieldy. Using only one wipe risks missing contamination; using more than four can complicate processing and interpretation. If the area is large or highly variable, you can create additional composites, but a single composite typically uses two to four wipes.