Project Description
In January 2011, petroleum hydrocarbon sheen was observed on the water in the Dominguez
Channel during low tide conditions approximately 400 feet south of the E. Carson Street bridge.
In April 2011, the Los Angeles Regional Water Quality Control Board (LARWQCB) issued
Investigative Orders to various entities with facilities in the area to assess petroleum hydrocarbon
impacts to soil, soil vapor, and groundwater. Resource Environmental LLC (RELLC), an industry
environmental management firm (www.rellc.net), was retained by Shell, Chevron, and Phillips 66
to manage the investigations under the direction of the LARWQCB. It should be noted that at the time there were other Potentially Responsible Parties (PRPs) that conducted their own investigations which are not included in this summary.
Since July 2011, RELLC has been conducting soil, soil vapor, groundwater, air, and residual
petroleum sampling within and along the Dominguez Channel south of E. Carson Street, along
pipeline corridors and at several industrial properties in the immediate vicinity, including the
former Carson Air Harbor facility at 21611 S. Perry Street, the former Texaco Service Station at
1209 E. Carson Street, the 76 Station #6082 at 1025 E. Carson Street, the former Active RV
property at 1202 E. Carson Street, the neighborhood east of the former Active RV property, and in the area of the Go Kart World facility at 21830 Recreation Road.
Summary of Environmental Investigation Results
Results of the investigations since July 2011 have indicated that the petroleum seeping into the
channel is a cracked naphtha mixed with a small portion of southern California crude. Cracked
naphtha is most commonly used as the primary material to make gasoline. The source is from
historical pipeline(s). Furthermore, historical operations at the former Carson Air Harbor, the
former Active RV, former Texaco, and 76 Station properties unlikely contributed to any sheen
entering the channel. However, remediation activity at the former Carson Air Harbor property
occurred in 2014 and the 76 Station remedial activities are ongoing. Both sites are no longer
RELLC’s responsibility. The channel sheening that has occurred appears to be primarily entering
into the waters from horizontal, perforated sub-drain pipe systems installed within the western
levee and secondarily from the sediments within the bottom of the channel.
Results of these investigations have also determined that the observed sheening is most likely
from pipeline release(s) from the 1950-80 era. The most likely scenario is that these leak(s)
occurred at a time when the regional underground aquifer was substantially lower than its
current levels. Over-pumping of the Los Angeles groundwater basin in the 1940s into the 1970s
led to large declines in regional groundwater levels and facilitated saltwater intrusion into the
basin. During this time, the suspected product release(s), unimpeded by groundwater, most likely
migrated downward to approximately 30-35 feet below the ground and just under the channel.
Since the early 1970s, the saltwater intrusion was mitigated by several fresh water injection projects including Los Angeles County Department of Public Works’ Dominguez Gap Barrier
Project. Imported and reclaimed water was injected into a deep aquifer just 2 – 4 miles south of
Dominguez Channel where this assessment is focused. As a result, groundwater levels gradually
recovered and eventually rose to the base of the Dominguez Channel in the 1990s to 2000s,
driving any of the released pipeline material that was mobile upward. By 2011, a limited area of
the sediment of the channel became saturated with the material released from the pipeline(s)
and migrated to the perforated side drains of the levee.
In general, the areas impacted by historic pipeline leak(s) have now been identified. To date,
RELLC has installed a significant number of borings within and outside the channel and also
monitors a large network of groundwater wells that provide a reasonable understanding of the
environmental condition in the project area and how these areas were impacted. Site
investigations indicated the larger source areas exist along the western levee. Isolated release
points of non-recoverable LNAPL have been detected outside of this area.
Timeline
Pending
- Evaluate the need for additional product recovery wells on the western levee.
- Develop viable alternative solutions for the long-term Remedial Action Plan (RAP).
Ongoing
January 2011 – Petroleum sheen discovered in channel.
April 2011 – Investigative Orders issued to PRPs by the LARWQCB.
June 2011 – RELLC began to conduct investigations.
July and August 2011 – Completed first phase of petroleum assessment, which included soil borings, well installations, sampling and chemical analysis of soil, channel sediment, soil vapor, groundwater, and petroleum at the Dominguez Channel and several properties in the immediate vicinity, including the former Carson Air Harbor property, the former Texaco Service Station, and the 76 Station #6082.
September 2011 – Completed outdoor air assessment.
October to December 2011 – Completed soil borings, well installations, and conducted additional soil and groundwater sampling along both sides of the channel, within Recreation Road, and at the former Active RV property.
December 2011 – Conducted soil vapor survey at the former Active RV property.
January and February 2012 – Conducted second phase of petroleum assessment in channel.
February and March 2012 – Installed additional groundwater monitoring wells at the former Active RV property, and completed offsite soil and groundwater sampling east of the former Active RV property in E. 218th Street
February and March 2012 – Conducted semi-annual groundwater monitoring.
April 2012 – Conducted soil and sub-slab soil vapor sampling at the former Active RV property.
June 2012 – LARWQCB determined that the former Carson Air Harbor property, the former Texaco Service Station, and 76 Station are not likely contributors to the petroleum releases observed in the channel.
February 2013 – Cleanup and Abatement Order issued by the LARWQCB to BP, Chevron, Phillips 66, and Shell.
May and June 2013 – Conducted semi-annual groundwater monitoring.
August 2013 – Prepared Interim Remedial Action Plan.
October-November 2013 – Conducted GeoTrax Survey™ screening across the channel, along the western channel levee, within Carson Street and Recreation Road, and at adjacent properties.
November 2013 – Conducted semi-annual groundwater monitoring and additional offsite soil and groundwater sampling in the neighborhood east of the former Active RV property. New wells were installed east of the former Active RV site within Ashmill and Cloverbrook Streets.
December 2013 – Sample newly installed wells east of the former Active RV site.
April 2014 – Conducted semi-annual groundwater monitoring.
May 2014 – Completed 13 confirmation soil borings per the GeoTrax Survey™ Screening Interim Report.
July 2014 – Installed LNAPL recovery well within the western levee. A passive skimmer was installed in the new well and approximately 7 gallons of separate-phase-product was removed from the well.
October 2014 – The passive skimmer was removed from the new well and replaced with an active skimmer. Conducted semi-annual groundwater monitoring.
November 2014 – Conducted four additional GeoTrax Survey™ lines to further assess the presence of recoverable LNAPL near the channel. Completed three additional GeoTrax Survey™ confirmation borings to further assess the presence of recoverable LNAPL on the western channel levee.
December 2014 – Installed new LNAPL recovery well within the western levee. Completed one additional GeoTrax Survey™ confirmation boring within the eastern channel levee to assess the potential presence of recoverable LNAPL. URS recovered approximately 15 gallons of separate-phase product from this well.
February 2015 – Conducted well destruction activities at the Former Texaco Service Station.
March 2015 – The RWQCB granted closure for the Former Texaco Service Station. An active skimmer was removed from well R-MW-6 and replaced with a passive skimmer. The active skimmer was installed in well R-MW-12. A hydrostatic pressure/tidal study to assess changes in groundwater elevations related to the water injections from the Dominguez Gap Barrier Project began at the end of the month.
April 2015 – Conducted semi-annual groundwater monitoring.
October 2015 – Conducted semi-annual groundwater monitoring.
December 2015 – Completed the hydrostatic pressure/tidal study and pulled the transducers from the wells.
February 2016 – Advanced four borings and installed three wells (R-MW-15, R-MW-16A, and R-MW-16B) within the western levee (refusal was encountered for attempted borings in Recreation Road).
March 2016 – Installed a passive skimmer in Well R-MW-15 along the western levee.
April 2016 – Conducted semi-annual groundwater monitoring.
July 2016 – Advanced four soil borings at the Go Kart World Facility. Conducted assessment of the storm drain along Carson street.
August 2016 – Conducted potholing assessment near LNAPL recovery wells along the western levee.
October 2016 – Conducted semi-annual groundwater monitoring.
March 2017 – Conducted sub-slab soil vapor sample at the Go Kart World Facility.
April 2017 – Project team was notified of an odor nuisance at the intersection of E. Carson Street and S. Perry Street and mobilized to identify odor source. Conducted daily monitoring of utility vaults in the vicinity of odor nuisance. Conducted semi-annual groundwater monitoring. Conducted sealing of storm drain joints in drain along Carson Street.
July 2017 – Project team responded to odor complaints with the City of Carson and the LA County Fire Department. Conducted monitoring of the vault boxes in the vicinity. Installed eight additional seals in smaller storm drain in the vicinity of the odor complaint.
October 2017 – Installed one additional seal in small storm drain in the vicinity of the odor complaint. Conducted semi-annual groundwater monitoring.
January 2018 – Project team observed Southern California Gas Company exposing a leaking natural gas line adjacent to the storm drain and utility vaults with previous observed odors.
April 2018 – Conducted semi-annual groundwater monitoring.
October 2018 – Conducted semi-annual groundwater monitoring.
March 2019 – December 2019 – Deployed absorbent booms when sheen was observed on the channel.
April 2019 — Conducted semi-annual groundwater monitoring.
October 2019 — Conducted semi-annual groundwater monitoring.
April 2020 – December 2021 – Deployed absorbent booms when sheen was observed on the channel.
April 2020 — Conducted semi-annual groundwater monitoring.
October 2020 — Conducted semi-annual groundwater monitoring.
April 2021 — Conducted semi-annual groundwater monitoring.
October 2021 — Conducted semi-annual groundwater monitoring.
April 2022 — Conducted semi-annual groundwater monitoring.
October 2022 — Conducted semi-annual groundwater monitoring.
March 2023 – December 2023 – Deployed absorbent booms when sheen was observed on the channel.
April 2023 — Conducted semi-annual groundwater monitoring.
November 2023 — Conducted semi-annual groundwater monitoring and conducted additional soil vapor sampling at the former Active RV property.
December 2023 — Conducted additional site assessment including advancing 2 soil borings east of the former Active RV property, one on Ashmill St. and one on Cloverbrook St., installing 2 groundwater monitoring wells southeast of the former Active RV property on E. 218th St., installing 2 groundwater monitoring wells west of the 405 on E. Lauder St., and installing 2 groundwater monitoring wells on Recreation Road, which is west of the Dominguez Channel and east of the 405.
January 2024 — Conducted groundwater monitoring for newly installed groundwater monitoring wells.
February 2024 – Deployed absorbent booms when sheen was observed on the channel. April 2024 – Conducted additional soil vapor sampling and sub-slab vapor sampling at the former Active RV property. May 2024 — Will conduct semi-annual groundwater monitoring.
- Weekly inspection and petroleum removal from levee sub-drain system and wells.
- Semi-annual groundwater monitoring.
- If sheening is observed in the channel, absorbent booms will be used to contain the sheen.