F.2.6 Data analysis

Figure F-2. Laboratory sampling schematic

Sampling can be conducted continuously by sampling for 6 hr or desired

interval. The initial trap can then be removed and replaced with a second in

order to collect another sample for 18 hr to give a 24-hr sample and so on. If the

sediment sample has high contaminant concentrations, which can result in trap

breakthrough, shortening sampling times can reduce the sampling period.

Samples can then be taken for much shorter periods of time (i.e., 1 or 2 hr) over

a prescribed interval such as 1 week. During the exposure, air is continuously

passed over the sediment with collection of air samples conducted daily for a

prescribed time to determine contaminant concentrations being emitted from the

sediment.

Step 5 Trap storage. Remove traps after each sampling interval, seal

ends with provided seals, and refrigerate. Sample holding time will be

dependent upon traps used. Commercially available air sampling tubes through

Supelco Inc. have a holding time of 7 days (refrigerated).

F.2.6 Data analysis

Flux Determination. Contaminant flux [NA(t)] from the chamber is

calculated by determining the total mass of material captured in a given time

interval using the equation

NA(t) = Dm / DtAc

(F-1)

Appendix F Laboratory Evaluation of Volatile Emissions and Volatile Dispersion Modeling