Which statement about VOC sampling with soil sampling devices is true?

• A. Tube samplers can be used to collect VOC samples.
• B. Augers can be used to collect VOC samples.
• C. No VOC sampling is possible with any soil sampling device.
• D. All samplers are equally effective for VOC sampling.

Answer: (A)

Volatile organic compounds are easily lost if you disturb the soil or let vapors escape, so sampling methods must capture the vapor phase or pore air in a way that preserves the VOCs for analysis. Tube samplers are designed to pull soil gas or pore air through a sorbent or a canister, trapping the VOCs as the sample is collected and kept intact for GC analysis. This makes them suitable for VOC sampling.

Using an auger to collect a VOC sample isn’t ideal because it retrieves solid soil and disturbs the subsurface, which can cause VOCs to volatilize and split away from the sample, leading to biased results. The idea that no VOC sampling is possible with any soil sampling device is incorrect because specialized devices like tube samplers (and other soil-gas probes) are specifically used to capture VOCs. Saying all samplers are equally effective is also false, since effectiveness depends on the device design and the sampling method for preserving and concentrating VOCs.

So, tube samplers are the appropriate choice for collecting VOC samples because they accurately capture and preserve volatile contaminants for analysis.