HomeMy WebLinkAboutJVS Sampling Protocols II_1_082523REMOVAL OF THREE TANKS AT
328 UNION AVENUE
BAKERSFIELD, CA
TANK REMOVAL PROCEDURES
It was the intent to abandon the three known small tanks in place because of the
structural support threat posed by removing the tanks. However, in the process of
removing the concrete flooring above the tanks it was determined that the
building east wall would not be affected by removal of the tanks. Authorization to
remove the 3 tanks was received from the Bakersfield Fire Department.
After the top of the tanks were exposed, the minor amount of used oil totaling
about 100 gallons from the 3 tanks was removed and pumped into a tote for later
disposal. The tops of each tank, which appeared to be designed for aboveground
use, were at ground level directly beneath the concrete cover. The interior of the
tanks was then steam cleaned by Clear Environmental Resources, Inc., and liquids
pumped into the same tote as the used oil. After the tanks were deemed
sufficiently washed dry ice was placed into each tank for purging of vapors. A
total of 5 pounds of dry ice was placed in each of the small tanks and 10 pounds in
the large one. The LEL and oxygen concentrations of each tank were determined
by a properly calibrated Combustible Gas Indicator (CGI). The concentrations data
are recorded in the referenced Tank Closure Certification form provided to the
Bakersfield Fire Department.
The tanks were removed from their burial location by use of tying a strap to the
top of each tank and pulling them from their burial cradle. Each tank was placed
nearby and inspected for obvious leakage. The three tanks appeared to be in
good condition, with no obvious sign of damage that would result in a release.
The burial cradle was also examined after removal of the tanks to assess whether
there were signs of leakage. The soil appeared to be free of leakage at the bottom
of the excavation. Some oil staining was obvious on the side of the excavation
which was assessed to be from overfilling or sloppy procedures filling the tanks
during use. The three tanks were transported to Sierra Recycling, on April 13,
2023, for recycling of the metal.
UST REMOVAL SAMPLING PROCEDURES
The three small tanks were removed from 328 So Union Avenue, and subsequent
soil samples were obtained immediately afterward on April 12, 2023. A total of
two samples were obtained from about two and five feet from the tractor bucket
used to excavate to the desired depths.
The first sample was obtained after excavating to about two feet. The depth was
determined by utilizing a measuring tape to determine the proper soil sampling
depth. The sampling depth was approved by Malcolm Moore of the Bakersfield
Fire Department. The two foot sample (J001) was obtained from the bucket of
the small excavator being used. The pre-cleaned lab certified glass sample
container was carefully filled with soil from the bucket. The entire 8 oz glass
container was filled with soil. After the sample was labeled, it was immediately
placed into an ice chest with ice.
The excavator operator was then directed to excavate to six feet to retrieve a
second sample at the desired depth. At about five feet the soil became extremely
hard, and very difficult to reach the desired six foot depth. After numerous
attempts to reach the desired depth with the excavator the fire department
approved the retrieval of the second sample (J002) at approximately five feet. The
second sample was obtained from the bucket of the excavator. The glass sample
container was filled with soil and labeled with the appropriate information. After
it was labeled, it was immediately placed in the ice chest with the first sample. A
chain of custody was completed with the appropriate information, including the
requested analysis method. All sampling activities were photographed and
documented by the Fire Department on-scene as well.
The samples in the ice chest were transported the same afternoon to Pace
Analytical Services for analysis.
SOIL SAMPLE RESULTS
The two soil samples were transported to Pace Analytical Environmental Sciences,
a certified laboratory for analysis of Total Petroleum Hydrocarbons (TPH) and Oil
and Grease of each sample. The samples were analyzed within the required
timelines as per EPA methods 8260B and 1664. The TPH results for J001 at 2 feet
were None Detectable (ND) and the Oil and Grease results were listed at 1000
mg/kg. The 5 foot sample J002 results for TPH were also listed as ND, and the Oil
Grease sample result showed a significant decline in concentration of 120 mg/kg
as compared to the 2 foot sample. All other constituents analyzed by EPA method
8260B were either ND or negligent.
Based on the soil sampling analytical results it appears that some of the oil
clinging to the side of the excavation may have fallen into the excavation and
resulted in being detected in the sample results. There is a clear decline in
concentration levels between the first at 2 feet and second sample at the 5 foot
depth. Based on available public information supplied in the Groundwater
Sustainability Plan (GSP) for the Kern River Groundwater Sustainability Agency
KRGSA Plan Area, Figure 3-16, the depth to underground source of drinking water
(USDW) in the area is approximately 6000 feet as referenced in the report and
commissioned by Gillespie et al.,2017. In the same report Figure 3-44 the depth
to groundwater in spring 1998 in the area was in the range of 50-100 feet. The
Environmental Screening Levels (ESLs) for contaminants in soil as published by San
Francisco Region Water Quality Control Board in February 2016 established
industrial TPH screening levels much greater than 1000 mg/kg in soil. The site
conditions at JVS were none detected for TPH at both 2 and 5 foot depths. The Oil
and Grease concentration levels declined between the 2 foot (1000 mg/kg) and 5
foot samples (120 mg/kg). The lack of negligible concentrations of hydrocarbons
at the 5 foot depth indicates that the tank integrity was maintained throughout
historical use of the tanks.
Based on established regulatory screening levels for the contaminants screened
on this project versus actual results, condition of the tanks after removal and lack
of obvious staining in the excavation it is prudent to expect that the site is suitable
for closure and no further environmental assessments is necessary.
Joe Canas CSP-24919