EnvirOmega Consultants Acoustical Study
r.
EnvirOmega Consultants (t
16732 Palmero Drive
San Diego, California 92128
(619) 676-0046
April 271999
Don Hubbard Contracting
P.O. Box 230577
Encinitas, California 92023-0577 •
•j
Attention: Mr. Don Hubbard
Subject: Project Update A
Don Hubbard Contracting Facility
46 Encinitas Boulevard
Encinitas, California 92024
i
Dear Mr. Hubbard:
On December 3, 1998, a representative of EnvirOmega Consultants (EOC) observed the
removal of two underground storage tanks (USTs) from your site located at 46 Encinitas
Boulevard in Encinitas, California. Each 1,000 gallon UST (one unleaded gasoline and one
diesel) was removed from a separate excavation with two soil samples collected from each
excavation. While neither soil sample collected from the excavation created by the removal of
the unleaded gasoline UST contained detectable concentrations of total petroleum
hydrocarbons (TPH), soil staining and hydrocarbon odors were noted in the excavation. Of the
two soil samples collected from the excavation created by the removal of the diesel UST, one
sample contained 3,200 milligrams per kilogram of TPH-diesel and the other did not contain a
detectable concentration of TPH. The regulator observing the removal of the USTs noted the
presence of a "small amount of diesel floating on surface of groundwater' in the excavation
created by the removal of the diesel UST.
Following the removal of the USTs and the departure of the regulator from the site, in
accordance with an approved "post tank removal work plan", EOC assisted with the excavation
of approximately 150 cubic yards of clean and contaminated soil from the excavation created
by the removal of the gasoline UST. During the excavation of the soil, it became apparent that
the soil removal should be discontinued and that the excavations should be backfilled. This
conclusion was based primarily on the fact that hydrocarbon odors continued to emanate from
the excavation and some soil staining was still apparent on the excavation sidewalls. It should
be noted that while soil removal was discontinued, the observed soil conditions did not
necessarily suggest extensive contamination. Instead, EOC, with your concurrence,
concluded that to avoid the possibility of removing excessive amounts of soil, soil removal
should be stopped and replaced with an assessment effort, including soil borings.
To address the subsurface conditions remaining in the areas of the removed USTs, EOC is
preparing a work plan proposing the excavation of several borings and the possible installation
of several groundwater monitoring wells. The County of San Diego Site Assessment and
Mitigation (SAM) Program of the Department of Environmental Health requires the assessment
Mr. Don Hubbard
April 27, 1999
Page 2
of the extent of petroleum hydrocarbon impact to the soil and groundwater at sites where
unauthorized releases have occurred and may require the mitigation of those impacts.
Currently, we understand that both UST excavations have been filled to the ground surface
with soil and that the soil removed from the gasoline UST excavation has been transported to
Candelaria Environmental in Anza, California for disposal and treatment. We will submit a
work plan proposing the advancement of soil borings and the collection of soil and
groundwater samples to SAM within the next week and should receive approval of the work
plan from SAM within four weeks of it's submission. Since you have been accepted into the
State Cleanup Fund, costs to perform the assessment work should be approved by the Fund
prior to the performance of the work. The preapproval should take no more than two weeks.
Following preapproval, a well permit application will be submitted to SAM with the fieldwork
being completed approximately three weeks later. Note that SAM requires a wait of two weeks
from the submittal of a well permit application before that the fieldwork can be completed. The
fieldwork should be completed within a few days with a report submitted to SAM with four
weeks of the completion of the field activities. Depending on the results obtained from the`
completion of the field activities, "site closure" could take as little as three months following the
submittal of the report but may extend up to as much as several years. SAM typically requires
one year of groundwater monitoring following the observation of contaminant impact to the
groundwater, but in the event that additional soil and groundwater impact requiring mitigation is
encountered, the time to site closure will likely be extended beyond one year. The time frame
to site closure can be much more accurately estimated following the completion of the
assessment effort.
We have attempted to provide a reasonable estimate of the activities and time required to
obtain closure for your site. If you have any questions or require additional explanation, please
call me at 619-676-0046.
Sincerely,
David A. Eminhizer
Environmental Scientist/Owner
EnvirOmega Consultants
cc: Mr. Bill Brown, Attorney for City of Encinitas