12
ERDC/CRREL TR-02-12
2
MATERIALS AND METHODS
General information
In the first phase of these experiments, the five devices were used to sample
contaminated water in a standpipe. The water in the standpipe contained either
mg/L or g/L concentrations of either several VOCs, explosives, pesticides, or
metals. In the second phase of these studies, the devices were used to sample
TCE-contaminated groundwater from one of our laboratory's deeper monitoring
wells.
Standpipes
The standpipes used to hold the contaminated well water consisted of 8-inch-
diameter, schedule-40 PVC pipe, approximately 8 feet long. For the bottom of
the standpipe, a PVC end cap was pounded on one end; no organic solvent was
used to join the end cap and casing.
Between experiments, the standpipes were cleaned using a high-temperature
(~99C) and pressure (1000 psi) washer with a 1% Liqui-Nox detergent solution,
and rinsed with hot water until no more suds were observed. The standpipe was
then filled and drained three times with deionized water.
Test solutions in the standpipe experiments
Explosives-contaminated water was obtained from Louisiana Army Ammu-
nition Plant. Initial concentrations in the standpipe were approximately 25 mg/L
for RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), 2,4,6-trinitrotoluene (TNT),
and 1,3,5-trinitrobenzene (TNB), 500 g/L for HMX (octahydro-1,3,5,7-tetra-
nitro-1,3,5,7-tetrazocine), and 100 g/L for 1,3-dinitrobenzene (DNB) and 2,4-
dinitrotoluene (DNT).
The VOC and pesticide solutions were made by adding the neat chemical
directly to deionized water in four five-gallon glass bottles. The solutions were
stirred for up to three weeks using a magnetic stirrer. As expected, the pesticide
solution took much longer to dissolve than the VOCs. Prior to pouring the pesti-
cide solution into the standpipe, the solution was filtered through a glass-fiber
filter to remove any undissolved particles of pesticide. The pesticide solution
contained three analytes: lindane, aldrin, and dieldrin. These compounds were
selected because they varied in their hydrophobic nature and propensity to adsorb