14
ERDC/CRREL TR-02-12
HydraSleeve, Discrete Interval Sampler, and PneumoBailer, paired samples
were taken by first taking a control sample, either from the standpipe or the well,
and then one with the sampling device being tested. The number of paired
samples varied with the type of analyte being studied and anticipated concen-
tration. There were six paired samples in the VOC studies and in the field study,
three in the explosives study, and five in the pesticides and metals studies.
In the field study, we gently removed the pump used to take the control
samples prior to taking the next sample with the sampler being tested. In most
cases, this was necessary because there wasn't enough room for both devices in
the well. For the controls, turbidity readings were allowed to equilibrate prior to
collecting a sample. Because of the time involved in allowing the well to re-
equilibrate, no more than two types of devices were tested in one day. The first
two sampling rounds with the HydraSleeve were taken on the first day. The
remaining rounds with the HydraSleeve and all the rounds with the Discrete
Interval Sampler were taken on day 2. All the rounds with the PneumoBailer
sampler and the first three rounds with the Kabis Sampler were taken on day 3.
The remaining rounds with the Kabis Sampler were taken on day 5.
For the diffusion bag samplers, the protocol was different. For the standpipe
experiments, three of the bag samplers were left in the standpipe for 13 weeks.
Just prior to removing the bag samplers, three control samples were withdrawn
from the sampling port. The bag samplers were then immediately taken to the
laboratory (up two flights of stairs), the bags were punctured with a glass pipet,
and the sample vials were filled using the pipet. In the field study, the control
samples were obtained after the bag samplers were removed and the well was
given time to equilibrate (~1 hour, with very low and stable turbidity readings).
Sample handling and analysis
Samples were collected in 40-mL glass VOA vials with Teflon-lined screw
caps. These vials were stored in a refrigerator overnight. The next day, an aliquot
was transferred to a glass, 1.8-mL autosampler vial using a glass Pasteur pipet.
Analytical determinations were performed using reversed-phase HPLC (RP
HPLC) using a modular system as described by Parker and Ranney (1997a).
Separations were obtained on a 150-mm 3.9-mm (4-m) LC-8 column
(Waters) and eluted at 1.4 mL/minute with 85/15 (v/v) water/isopropanol (Walsh
and Ranney 1999, Jenkins et al. 2001). The UV detector was set at 254 nm with
the digital integrator operating in the peak height mode.
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