Phase 1: July – September 2011
- Installed and sampled six groundwater monitoring wells in the access roads along the eastern and western sides of the channel
- Drilled 12 shallow soil borings within the channel bed and collected soil, sediment, and petroleum samples
- Installed absorbent materials along channel levee sub-drain manholes near the area where petroleum sheen had been observed, conducted weekly inspections and replaced absorbent material as necessary, and removed petroleum daily from monitoring Well R‑MW-6, where liquid petroleum accumulates
- Chemically analyzed sediment, soil, groundwater, petroleum, and saturated absorbent material samples
-- Conducted an outdoor air assessment
Summary of Results: Petroleum seeping into the channel appears to be a refined oil product (a cracked naphtha) from one or more pipeline sources. Specific pipeline source(s) are unknown. Results from the outdoor air assessment did not reveal a health risk from the odor of a sheen that was observed partially covering the channel.
Phase 2: October 2011 – February 2012
- Installed and sampled nine additional groundwater monitoring wells in the access roads along the eastern and western sides of the channel and three wells within Recreation Road
- Drilled 20 additional shallow soil borings within the channel bed and collected soil and petroleum samples
- Chemically analyzed soil, groundwater, and petroleum samples
- Conducted removal of petroleum from groundwater monitoring Well R-MW-6 in the western levee access road
- Continued weekly inspections and replacement of absorbent material in the channel levee sub-drain manholes, and removed petroleum daily from monitoring Well R-MW-6, where liquid petroleum accumulates
Summary of Results: The extent of recoverable petroleum appears to be limited to the immediate area of the channel in the vicinity of a pipeline corridor that crosses the channel and along the western levee at Well R-MW-6 approximately 950 feet south of E. Carson Street. Investigative work performed along the eastern levee and the former Active RV site has not revealed a similar release point of petroleum contribution east of the channel. An Interim Remedial Action Plan (IRAP) was prepared to prevent degradation of the surface waters of the Dominguez Channel while a more permanent remedy is developed and implemented.
Phase 3: October 2013 – 2014
- Conduct GeoTrax Survey™ screening across the channel, along the western channel levee, within Carson Street and Recreation Road, and at adjacent properties (GeoTrax Survey™ is a non-invasive tool that allows one to better understand soil and groundwater impacts along the survey lines)
- Install additional petroleum recovery wells along the western channel levee
- Conduct exploratory trenching along the pipeline corridor within the western channel levee
- Continue weekly inspections and replacement of absorbent material in the channel levee sub-drain manholes, and removal of petroleum from monitoring Well R-MW-6, where liquid petroleum accumulates
Results: Implementation of the Phase 3 work is underway, and the results are pending. A comprehensive Remedial Action Plan will be prepared in 2014.
- Weekly inspection of the channel levee sub-drain manholes for petroleum sheen, replacement of manhole absorbent socks as necessary, and daily removal of petroleum that accumulates in Well R-MW-6
- Semi-annual groundwater monitoring