Module 4 · Sampling and Laboratory Data

Clean Collection

Trace-level sampling requires controlled movements. Keep the cap in your hand. Do not place it on a railing, clipboard, or other surface. Fill the Method 1633A bottle to the shoulder so frozen storage has headspace. If it overflows, discard the bottle and collect a new sample. Do not pour off the top because PFAS can collect at the air-water interface.

Key: = PFAS crowding the water surface

Close

After capping, rinse the outside with PFAS-free water if sample contacted it. Place each bottle in its own self-sealing bag and then into the cooler. EPA advises collecting the sample before attaching or writing on labels and avoiding permanent marker directly on the bottle.

Follow the project plan for gloves, clothing, cosmetics, sunscreen, field gear, and food packaging. The plan and laboratory guidance control the event.

Stage the site before opening the bottle. Confirm the sample ID, collection point, safe body position, cooler, bag, blank water, and custody materials. If wind, spray, traffic, or an unstable platform makes clean collection impossible, stop and correct the condition. Do not balance an open bottle on grating or reach across an unguarded channel. Trace-level cleanliness never overrides fall protection, biological-exposure controls, or traffic safety.