HomeMy WebLinkAbout[Untitled]_2017012011174374_5-6Former Garriot Crop Dusting - 3 - 10 February 2016
Bakersfield, Kern County
Closure Summary
Soil Gas Investigation
Three permanent soil gas wells installed at the former USTs and dispenser island area, and
along the wall of buildings to the east, were sampled during December 2014 to determine if the
criteria contained in the Policy for Petroleum Vapor Intrusion to Indoor Air were satisfied. The
samples were analyzed for TPHg by EPA Method TO 18; and volatile organic compounds
(VOCs), including BTEX, fuel oxygenates, lead scavengers and naphthalene by EPA Method
T015. TPHg was detected at up to 2,100 micrograms per cubic meter (pg/m 3 ). Benzene,
ethylbenzene and naphthalene were not detected above the method detection or reporting
limits, which ranged from 14.54 - 22.67 pg/M3 . The concentrations did not approach or exceed
the Commercial soil gas screening levels, with or without a Bioattenuation Zone contained in the
Policy Appendix 4, or other applicable California and Federal environmental screening levels.
The consultant concluded that Policy criteria were met.
Sensitive Receptors
The Site is within an area of commercial/industrial properties at a municipal airport. A sensitive
receptor survey conducted by the consultant during 2014 did not identify supply wells, surface
water bodies, schools, hospitals, or churches within 1,000 feet of the release.
Low-Threat Under-ground Storage Tank Case Closure Policy Evaluation
The subject UST release satisfies all relevant General Criteria:
a. The release is within the service area of a public water system;
b. the release consists only of petroleum;
c. the ("primary") release from the UST system has been stopped;
d. free product is not present. The criteria for free product removal to the maximum
extent practicable is not relevant;
e. a Conceptual Site Model has been completed. The assessment and sensitive
receptor survey contained in site assessment reports provide sufficient data for
Central Valley Water Board staff to complete the Conceptual Site Model;
f. secondary source has been removed to the extent practicable. The remaining
source mass is expected to naturally degrade;
g. soil or groundwater have been tested for methyl tertiary butyl ether (MTBE), in
accordance with Health and Safety Code section 25296.15; and
h. nuisance as defined by Water Code section 13050 does not exist.
The subject UST release satisfies the relevant Media-Specific criteria:
1. Groundwater — The release has not affected groundwater - the criteria are not relevant.
2. Petroleum Vapor Intrusion to Indoor Air — The release satisfies criteria contained in
Appendix 4, Appendix 4 (Direct Measurement of Soil Gas Concentrations).
3. Direct Contact and Outdoor Air Exposure - Benzene, ethyl benzene, and naphthalene
concentrations exceeding human health screening levels listed in Table 1 were not
detected in areas of potential shallow soil contamination during previous investigation.
The subject UST release satisfies criteria in the Low Threat Case Closure section:
a) Municipal and county water districts, water replenishment districts, special act districts
with groundwater management authority, agencies with authority to issue building
permits for land affected by the unauthorized release, and the owners and occupants of
the property affected by the unauthorized release, and owners and occupants of all
parcels adjacent to the impacted property have been notified of the proposed case
closure and were provided a 60 day period to comment. A Public Notice of the proposed