Fig. 4. Field setup for testing the loss of dissolved concentrations of trichloroethylene (TCE) and tetrachloroethylene (PCE) during sample compositing or from exposure to air for 60 min. For illustration purposes, bottles are illustrated as black or white; however, in the actual field test, all bottles were 1-L amber glass. Bottles on the lab carts were capped until sampled. Bottles on the collector columns were uncapped throughout the 60-min test period.