G-Logics was retained by a commercial property owner to replace the current
environmental consultant providing services on a property in Olympia, Washington.
Subsurface soil contamination by dry-cleaning solvents (tetrachloroethene, perc, or PCE)
was discovered at the northwest corner of the subject property, around the location of a dry-
cleaning and laundromat business. Although not responsible for the release of the
contaminants, the property owner wanted to review the cleanup requirements for the
property and to ultimately seek a no further action (NFA) determination from Ecology.

To better understand the extent of the
discovered PCE contamination,
G-Logics conducted additional site
explorations at exterior and building-
interior locations. These explorations
identified higher concentrations of site
contamination by PCE, which also was
more widespread (both horizontally and
vertically) than was previously indicated.
This exploration also detected
petroleum-hydrocarbon contaminants in
the northern portion of the property,

which indicated possible property impacts due to an adjacent automobile-service facility.
Additionally, the possible source or sources of the site contamination also were not fully
understood. This was confirmed during the site visits where G-Logics observed several
suspect areas. These included 1) the possible location of a former underground storage tank
at the west side of the building, 2) the location of a floor drain located in the area of the
dry-cleaning machines, and 3) extensive staining in the former location of self-serve dry-
cleaning machines.

Based on the results of the exploration and a meeting with current and previous dry-cleaning
business owners, a risk-based remediation approach was developed. This work includes the
installation of additional interior and exterior soil borings (several to be completed as soil-
vapor extraction wells), additional groundwater-monitoring wells, the performance of a soil
vapor extraction (SVE) testing, and a groundwater-use review. A gaseous-aqueous
partitioning evaluation also was recommended to better understand the possible presence of
residual DNAPL (dense non aqueous phase liquid, such as free phase PCE) in the vadose

zones above the regional groundwater. This
new information would provide additional
direction regarding the level of effort and
duration of any necessary cleanup actions
required by MTCA. The vapor-extraction test
would provide information regarding the
potential benefits that a SVE system would
provide. If identified, the presence of DNAPL
would complicate and prolong any site
cleanup actions.

Based on this technical information, G-Logics
intends to perform an analysis under the
revised Model Toxics Control Act (MTCA)

regulation to determine the appropriate soil and groundwater cleanup levels to be met at this site, including consideration of risk-based modifications to the specified default assumptions. Appropriate points-of-compliance for the measurement of these identified cleanup levels also will be identified. A determination of appropriate "Remediation Levels" also will be performed, with the results applied at this site.

After G-Logics identifies appropriate cleanup levels (remediation levels) and points of compliance, an evaluation of cleanup-action alternatives will be performed. This evaluation would identify viable cleanup alternatives and would screen the alternatives for likely success, costs, and restoration time frames. Alternatives to be reviewed would include source control, soil-vapor extraction, institutional controls, natural attenuation, air sparging, pump-and-treat, bioremediation using hydrogen release compound, and vertical-circulation wells.

Information generated through this process will be provided to Ecology in accordance with the reporting requirements of MTCA and to document the performed independent remedial action under Ecology's Voluntary Cleanup Program. The ultimate goal at this site is to receive an NFA designation from Ecology.

After this site was reported to Ecology, Ecology initiated a Site Hazard Assessment to determine the relative risk to human health and environment that this site presents. G-Logics assisted Ecology, and their contractor (the Thurston County Health Department), in performing the evaluations and calculations under Washington's Ranking Method model. Based on support provided by G-Logics to the Health Department, the site received a numerical ranking of 3 rather than the ranking of 2 that Ecology initially proposed. This lower ranking allowed our client to avoid additional regulatory pressures from Ecology to expedite site investigation and cleanup and also allowed them the time to work with the former dry-cleaner operators to fund the remaining site work.