fcSz) West Lake Update
May 19,2015
EPA Directs PRPs to Perform Additional
RIM Characterization This Summer
EPA Region 7 has reviewed and approved the
Phase ID Work Plan Addendum submitted by the
Potentially Responsible Parties (PRPs) in April
2015. The purpose of the Phase ID investigation
is to build on previous work conducted at the site
to identify the extent of radiologically impacted
material (RIM) in the southwestern and western
portions of Operable Unit 1 (OU1) Area 1, and to
assist EPA in evaluating potential locations for an
isolation barrier. Contractors began mobilizing at
the site on May 11th.
Contractors under EPA oversight will use Gam-
ma Cone Penetrometer Testing (GCPT) to screen
for gamma radiation. Once these locations and
depths are established, contractors will use a sonic
drilling rig to drill soil borings to collect soil core
samples from GCPT locations that have elevated
gamma readings. The borings will be visually
inspected and scanned for gamma radiation to
identify the locations where soil samples will be
collected for laboratory analysis.
The samples will be analyzed for the fol-
lowing isotopes: Radium-226, Radium-228,
Thorium-230, Thorium-232, Uranium-234,
Uranium-238, Actinium-227, Potassium-40, Prot-
actinium-231, Scandium, and Lead-210. Consis-
tent with EPA quality control practices, laboratory
analytical reports and data will be subjected to
data validation in accordance with the Multi-
Agency Radiation Laboratory Analytical Protocol.
In addition to the investigation work described
above, EPA Region 7 sent a letter to the PRPs on
April 20, requesting additional RIM characteriza-
tion at Area 1 and Area 2 of the West Lake Landfill
Site. Hie purpose of this planned additional char-
acterization is to better define the extent of the
RIM in OU1 Areas 1 and 2 to support a thorough
evaluation of full and partial excavation remedy
EPA has worked closely with its Office of Re-
search and Development (ORD) and the U.S.
Army Corps of Engineers to review existing data
from Areas 1 and 2 to define the appropriate scope
of this additional sampling effort. The additional
samples required by this work will be collected
using the same GCPT sampling and confirmation
sonic coring that will be used for the Phase ID
work described above. This additional character-
ization will be planned and implemented concur-
rently with the upcoming Phase ID work in order
to maximize the speed and efficiency with which
both events can be completed.
EPA expects the work to last through the sum-
mer. The Phase ID Work Plan Addendum and
the April 20 letter to the PRPs are now available
at this website: www.epa.gov/region7/cleanup/
we st_lake_lan dfill
Community Inquiries
Ben Washburn
Find Us On
The GCPT direct push rig in action during characterization work at
the West Lake Landfill Superfund Site in Bridgeton, Mo., in 2013
Community Advisory Group Meeting
The next Community Advisory Group (CAG)
meeting will be held June 8 at 6:30 p.m. at the
Operating Engineers Local 513 Offices, 3449 Hol-
lenberg Drive, Bridgeton, Mo. 63044.