Sampling at Radford Army Ammunition Plant
Field investigations are
currently taking place at Radford Army Ammunition Plant (RFAAP) in
support of Work Plan Addenda 09 and 012. Environmental samples are
being collected at both the Main Manufacturing Area (MMA) and the
New River Unit (NRU) for chemical analyses. Fifteen sites are being
investigated and a groundwater study is being conducted in the MMA.
This handout discusses sampling techniques and presents
photographs of sampling activities.
Surface soil samples are normally collected with a stainless
steel trowel and homogenized in a stainless steel bowl. Surface soil
samples are collected in the first foot of soil. Samples for
volatile organic compounds (VOC) analyses are collected from 6-12
inches in depth to help prevent loss to air. Deeper soil samples
(subsurface soil samples) are collected by direct push methods.
Geoprobe/Direct Push Operations
The geoprobe rig is a method for obtaining subsurface soil
samples with a minimum of disturbance to the surrounding land. The
rig can be mounted in the back of a pickup truck (see
photo) or on a small ATV/4-wheeler vehicle for access to remote
locations. Soil samples are collected in a disposable acetate (a
non-reactive plastic material) sleeve lining the inside of a 4-foot
long, 3-inch diameter metal pipe. The cutting shoe is placed over
the end of the liner and screwed into the pipe and acts like a drill
The pipe is then placed in the geoprobe unit and advanced by
hydraulic pressure. The pipe is directly pushed into the ground
until resistance is encountered. At that point, the geoprobe
operator can use the unit to vibrate the pipe further into the soil
through a series of rapid blows, much like a jackhammer.
Once the pipe has been advanced 4-ft (the length of the pipe), a
pulling cap is placed on the end of the pipe. The geoprobe unit then
hydraulically pulls the pipe back out. The cutting shoe is removed
and the acetate liner, now full of soil, is pulled out of the pipe.
This soil sample represents a column or core taken from that
location (see photo). The
geoprobe operator labels each end of the core with the depth of the
top and bottom so that its orientation is known.
Deeper samples can be collected from each boring in 4-ft
increments by adding drill rods to the top of the pipe and advancing
further down each hole. These continuous cores can also be useful in
assessing changes in the geology, as at the Rubble Pile, (SWMU 58).
The geoprobe cores were used at that site to identify the depth of
manmade fill and the beginning of native soil.
Sediment samples are collected from drainage pathways,
impoundments, stream and pond beds to help assess if constituents of
concern are migrating by surface water flow or impacting ecological
receptors. Sediment samples can be collected with trowels and
stainless steel bowls, or for samples in deeper water an Eckman
sampler can be used. An Eckman sampler consists on an open container
attached to an extendable rod. Once the sediment is reached, a lever
closes a lid on the bottom of the container and the sediment sample
can be retrieved. For deeper sediment samples a vibracore rig can be
Vibracore sediment sampling techniques were employed in three
lagoons at SWMU 31- Coal Ash Settling Lagoons to obtain virtually
undisturbed sediment samples at depth (see
photo). Vibratory coring
uses a vibrating head assembly, which is clamped, onto an aluminum
pipe. The head assembly vibrates the pipe into the sediment column
until the desired depth is obtained. Once the desired depth is
reached, water is poured into the standing pipe to create a vacuum
effect inside the tube to aid in the full recovery of a sample. An
example is putting your finger over a straw full of water. The top
of the pipe is then capped off and the pipe is extracted with an
electric winch. The pipe is then positioned horizontally where two
lengthwise cuts are made with a power shear to open the core for
sampling (see photo).
Surface water samples are normally collected straight into the
jars in which they will be submitted for laboratory analysis.
Surface water samples are normally collected at the same locations
as sediment samples (see photo).