What practices reduce cross-contamination during sampling?

• A. Use shared equipment between sites
• B. Sampling without decontamination
• C. Strict sampling protocols
• D. Dedicated sampling equipment, proper decontamination procedures, field blanks, and strict sampling protocols

Answer: (D)

Preventing cross-contamination in sampling hinges on controlling what comes into contact with each sample and how samples are handled from collection through analysis. Using dedicated sampling equipment for each site or sample prevents material from one location from being carried to another. Proper decontamination between samples, including cleaning or sterilizing tools and containers, minimizes any residual contamination that could carry over. Field blanks—samples that travel through the sampling process without actually collecting the target material—help detect contamination introduced in the field environment or during handling. Strict sampling protocols ensure consistent, traceable procedures for collection, labeling, storage, and transport, reducing human error that could introduce contamination. Taken together, these practices address both equipment-related transfer and procedural gaps, making results more reliable. The other options fail because shared equipment can transfer contaminants, and skipping decontamination leaves carryover residues; relying on protocols alone without addressing equipment and field checks is insufficient to prevent contamination.