851 High Street in Auburn, California
E2C Remediation was hired in 2004 to clean up the site of a former gas station with a long history of
releasing unauthorized petroleum products. Since 1989, one year after Placer County received the first
report of an unauthorized release at the site, 3 monitor wells have been installed, and between 1989
and 1993, free product was removed, at times on a weekly basis, from MW-3.
Five additional monitoring wells were
installed in April of 1995, and in
December, a temporary remedial system
was installed. Just two years later, in
October of 1997, the 10th monitoring well
was installed, and in 2003, a Dual Phase
Extraction system was also installed on
the site.
In December of 2004, sixteen years after
the first report of unauthorized release,
E2C Remediation was hired to lead the
remediation of the site in Auburn. Work
began quickly, and in July 2005, E2C’s work plan to restart the DPE system was approved by the Regional
Water Board; however, this became impractical because of the City of Auburn’s regulations relating to
the discharge of treated groundwater.
E2C proposed a new work plan in November of 2005 recommending ozone sparging as a solution to
remediate the site, which was approved in February of 2006. E2C worked diligently with the Regional
Water Board between April 2006 and April 2007, conducting a bench scale test, which proved ozone
sparging was an effective and viable treatment method. E2C Remediation also submitted several
additional work plans for an in-field ozone sparge pilot test and contingency plans in the event of any
byproducts from the ozone sparging.
E2C was approved to conduct a 90-day in-field ozone sparge test in April 2007, which resulted in the
long-term operation of an ozone sparge system on-site through November 2011.
E2C Remediation continued working on the site at 851 High Street, and from January to October in
2012, E2C conducted sub-slab soil vapor sampling, confirmation soil borings on site, and prepared a Tier
2 Human Health Risk Assessment. The Regional Water Board agreed with E2C’s recommendation for
closing the site and a No Further Action Report was submitted in December of 2012.
Come May of 2013, destruction of the wells on site was requested by the Regional Water Board, and a
No Further Action letter was issued on September 16, 2013.
26900 Bear Valley Road, Tehachapi.
Three gasoline Underground Storage Tanks (one waste oil Underground Storage Tank, two multiproduct dispensers, and the corresponding piping) were removed from an operating gas station in
Tehachapi in August of 1998. As a result of testing during the removals, fuel hydrocarbons were
discovered in high concentrations in the surrounding groundwater, shortly thereafter, 19 groundwater
monitoring wells were installed at the site.
E2C Remediation was hired in 2001 to take over
the environmental remediation project, and in
January of 2003, both on-site and off-site
remediation system elements were installed. E2C
also operated a Vapor Extraction/Groundwater Air
Sparging System, and between January 2003 and
August 2005, over 86,000 pounds of fuel
hydrocarbons were removed from the site.
Come 2005, high-vacuum extraction (HVE) had begun to assist with E2C’s remediation efforts, and
between July 2008 and June 2011, HVE with hydrogen peroxide injections was conducted in limited hot
wells. During the end of 2011, remediation was discontinued and post-remediation groundwater
monitoring began.
In response to E2C’s Groundwater Monitoring Report during October of 2012, the Water Board outlined
the actions required for final consideration of closing the site under the Low-Threat Closure Policy.
After completing all of the necessary actions in April of 2013, E2C submitted its Human Health Risk
Assessment, Soil Gas Survey, and Conceptual Site Model Report. On July 17, 2013, the Water Board
agreed with E2C’s request for closure, and requested the destruction of the wells. On February 17, 2014,
E2C received the Case Closure Letter from the Water Board.
320 G Street in Lincoln, California
320 G Street in Lincoln, California has been the site of an operating gas station since 1971. During the
construction of a convenience store and two new dispenser islands in 1989, significant contamination
was discovered on site. In 1990, when monitoring wells were installed, floating liquid hydrocarbons (free
product) were found in the wells.
E2C Remediation took over remediation of
the site in December of 2004, and in April
2005, E2C replaced the original remediation
system with a larger and more efficient
remediation system. E2C was then able to
shut down the remediation system in June of
2010 due to dramatically reduced
concentrations of contamination in the
vapor. A shallow soil vapor survey was
conducted in December of 2010, and E2C
detected no fuel hydrocarbon concentrations in the soil.
In June 2011, the Central Valley Regional Water Quality Control Board requested verification
groundwater monitoring in response to the soil vapor survey results. The Board stated that if the results
were fine, a request for closure could be filed.
The verification groundwater monitoring findings came back acceptable, and in April 2012, E2C filed a
No Further Action Request. The Water Board approved this request, and requested destruction of all
wells on site in February of 2013, following the 60 day public notice period.
In July 2013, after the destruction of all wells on site, the Water Board issued a No Further Action letter
noting that 80,300 pounds of petroleum had been removed from the site as a result of vapor extraction,
free product removal, and natural attenuation.
401 Natomas in Folsom, California
The site at 401 Natomas in Folsom, California was home to a gas station and car wash, and in 1992,
multiple underground storage tanks were removed. During the removal of the storage tanks and
product lines to and from the product dispensers, contamination was discovered. In 1993, the
installation of monitoring wells began and a total of 9 wells were installed on and surrounding the site.
E2C Remediation took over remediation of the Folsom site
in late 2004. At this time, multiple monitoring wells were
showing total petroleum hydrocarbons-gasoline as high as
38,000 ppb, 25,000 ppb, and 9,000 ppb. MTBE was also
discovered in monitoring wells up to 1,700 ppb, and
benzene was found up to 8,800 ppb.
In 2006, E2C started a course of high vacuum extraction
(HVE), and in August 2008, installed a soil vapor extraction
remediation system. Following the installation of the
remediation system, total petroleum hydrocarbonsgasoline in the most highly contaminated monitoring wells
was reduced to 81.2, 185, and 127 ppb. MTBE had been
lowered to a high of 85 ppb in one well, and benzene had
been lowered to non-detectable levels in all of the wells.
E2C sought closure through of the site Sacramento County
after continued quarterly sampling in 2013. Sacramento
County granted approval of the closure in late 2013, and
following all final closure activity, closure of the site was
formally granted in August of 2014.
Busy Bee Dry Cleaners in Lodi, California
In November of 2000, due to alleged dumping of dry cleaning solvents by previous local area businesses,
the City of Lodi and the Eastern District of California filed a lawsuit in federal court ordering cleanup at
the former Busy Bee dry cleaners site. The lawsuit went to a settlement in 2005, with the Defendants
placing $475,000 into a trust with the purpose of cleaning up the site, and E2C Remediation was
awarded a Pay for Performance contract to undertake the site cleanup.
E2C installed two separate remediation system compounds and several air sparge wells, groundwater
monitoring wells, and extraction wells because of the
wide contamination plume (spreading over almost 3
city blocks).
Following E2C’s remediation strategy, the Central
Valley Regional Quality Control Board issued a No
Further Action Determination on June 2, 2014. The
Control Board found that E2C had “satisfactorily
completed remedial actions and has achieved the
applicable remedial action standards and objective for
the site.”
(See
http://geotracker.waterboards.ca.gov/view_documents.asp?global_id=SLT5S0583099&enforcement_id
=6205348)
Work Has Begun at the Leona Heights Sulfur Mine!
From as early as 1900 through the 1920s, the Leona Heights Sulfur Mine operation was mining pyrite
from the sites bedrock and used to manufacture sulfuric acid. Natural water flowing over and through
the mining waste subsequently dissolves sulfur and other types of metals, leaving an acid drainage that
flows into the nearby Leona Creek. Because the creek receives most of its water from groundwater
seep, during heavy rain events, runoff from the watershed upstream reacts with the mining waste. This
further increases the amount of acid mine drainage
flowing into the creek, and water samples taken from this
site have had pH levels as low as 3. The solubility of
metals present in the mining waste increases with the
introduction of acidic water, causing the leaching of
heavy metals into Leona Creek. You can see that the
Leona Creek has the tell-tale orange color associated with
acid mine drainage, and it does in fact, contain high levels
of cadmium, copper, nickel, mercury, arsenic, and zinc.
E2C has proposed the following actions be taken to effectively remediate the site:


Removal of mining waste from Leona Creek and surrounding areas
Grade and compact mining wastes. Install a subsurface drainage system beneath the compacted
mining waste to increase stability.




Isolate the mining wastes from the water by covering with a geomembrane liner and a
vegetated soil layer.
Create new discharge point within the creek channel by rerouting the seep drainage from its
current location.
Reinforce steep slopes surrounding the Leona Creek to improve consolidated mining waste
stability.
Construct a stable creek channel that can accommodate a 100-year design storm and support
natural sediment transport. Incorporate cascades and step-pools that mimic natural creek
channels on steep slopes.
These outlined actions for consolidation, revegetation, capping, and drainage improvements are
designed to substantially reduce the contact of storm water runoff and mining wastes, effectively
reducing the metal and excess sediment load in Leona Creek.