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UST Closure, Assessment and Remeditation - Beaverdam, OH
UST Closure, Assessment and Remeditation - Beaverdam, OH
This project included the removal of underground
storage tank (UST) systems, completion of BUSTR Tier 1 and Tier 2
investigation, and remediation of soil and groundwater
contamination. The subject property consisted of a 14-acre
abandoned truck stop/fueling station located in Beaverdam,
Ohio. The client, a local commercial lending firm, acquired
the property through foreclosure and inherited the liability
associated with the UST systems.
Allied conducted all aspects of the excavation, removal, and
disposal of eleven (11) UST systems containing gasoline, diesel
fuel, kerosene, heating oil and waste oil. The fueling
systems included ten (10) dispenser islands and several hundred
feet of piping. Free product encountered at the time of UST
removal necessitated interim response actions including the removal
and disposal of 24,400 gallons of petroleum contaminated water, and
excavation and disposal of 940 cubic yards of petroleum
contaminated soil.
The
UST Closure Assessment conducted at the time of removal
determined that concentrations of benzene in groundwater within the
UST cavity exceeded action levels. Due to the elevated levels
of benzene found, it was determined that additional assessment
(i.e. Tier 1 Assessment) was required to delineate the extent of
contamination at the site.
The purpose of the Tier 1 assessment was to confirm the
contaminants of concern and points of origin, evaluation of
exposure pathways and transport mechanisms, development of
appropriate action levels, and the determination of the vertical
and lateral extent of contamination. The assessment included
the advancement of 32 soil borings and the installation of four (4)
monitoring wells. Results of the Tier 1 assessment indicated
benzene, xylenes, toluene and ethylbenzene as contaminants of
concern, and revealed two contaminant sources: the former UST
cavity and the former remote fuel dispenser island. The
assessment also revealed a complex geologic setting, including two
water-bearing zones: a shallow sand seam, and a deeper sand
aquifer. Soil at the source areas, and groundwater within the
upper saturated zone were affected by petroleum contamination.
To better define the extent of contamination and provide
predictions of contaminant behavior, Allied conducted a Tier 2
assessment. The assessment included installation of
additional groundwater monitoring wells, and development of
computer-ge
nerated flow and transport models to estimate
potential contaminant migration patterns and rate of
attenuation. The models predicted that groundwater
contamination would not migrate onto adjoining properties and would
naturally attenuate to acceptable concentrations over time.
Based on this data, Allied proposed a remedial action plan
consisting of the excavation of remaining contaminated soil, and
natural attenuation of groundwater coupled with quarterly
monitoring and implementation of an Environmental
Covenant-Not-To-Sue. The covenant included groundwater use
restrictions. This plan was approved by Ohio BUSTR and the site
ultimately received a corrective action status of No Further Action
(NFA). Petroleum contaminant concerns were successfully
abated and the property is currently on the market for sale.