The collection options are:

• En Core Sampler Preservation

Collect 3 En Cores and a dry weight for each sample point. Ship to lab within 48 hours of collection.

• Methanol Preservation

Requires coring and weighing 5 gram samples and placing in 40 mL vials preserved with methanol. VOC losses are prevented by both retarding volatilization and preventing biodegradation. However, this method involves use of a hazardous substance and weighing samples in the field. VOC detection limits are elevated 25 to 50 fold. Unused methanol and samples must be disposed of as hazardous waste.

• Acid Preservation

Requires coring and weighing 5 gram samples and placing in 40 mL vials preserved with an acid solution (formed from sodium bisulfate). While this method overcomes the methanol objections and eliminates subsampling in the lab, different limitations are presented:

• Acid may be insufficient for preserving soils with high buffering capacity.
• Alkaline soils may react vigorously with the acid and the vials may explode.
• Acid may salt in or salt out contaminants, depending on organic carbon content.
• A high level analysis may be needed in addition to the low level analysis.