Environmental Engineering Reference
In-Depth Information
Samples were analyzed for methane, ethane, and ethene using an HP P200
Series Micro Gas Chromatograph and a thermal conductivity detector.
5.4.2.2 Core material collection
Subsurface sediment samples were collected for direct molecular analysis
(16S and PLFA) prior to the cosolvent flushing test and at approximately 1
and 2 years after the cosolvent flushing test. Samples were collected from
approximately 7.9 to 9.4 m bgs to coincide with the zone targeted by the
cosolvent flushing test. The results of the molecular analysis are not available
at this time. Subsurface materials collected from these locations and locations
where additional MLS, injection/extraction wells, and monitoring wells
were installed have also been used as a source of material and microorgan-
isms for laboratory biotransformation studies.
Core materials collected for the molecular analysis prior to the cosolvent
flushing test were put into sterile conical tubes and frozen by immersing
into a liquid nitrogen canister for 2 to 5 min and stored frozen until analysis.
Sterile spatulas were utilized to obtain samples of the undisturbed centers
of the core. Between core sections, all materials used were sterilized with
isopropyl alcohol. Core materials were collected from IW-3, as this well was
installed, from the area between RW-6 and RW-7 (C6), and near MW-2 (C5).
Additional materials were collected during installation of the C-wells (C1 to
C4, C7). Locations of these samples are shown in Figure 5.8.
In July 1999 and July 2000, core materials were collected near the original
locations using the direct-push Simco rig. These materials were collected
into polyethylene sleeves that were sectioned by sawing and then capped
N
C7
C20
C37
C4
C12,13
C34
C3
C15
C33
C2
C14
C32
C1
C16,17,18
C31
C6
C10,19
C36
Core Locations
1998 Samples
1999 Samples
2000 Samples
C5
C1
C35
Figure 5.8
Locations of core materials collected for molecular analysis.
