Phase 1: October – December 2011
– Installed and sampled six onsite groundwater monitoring wells
– Chemically analyzed soil vapor, soil, and groundwater samples collected from onsite probes and wells
– Installed and sampled 10 soil vapor probes to assess potential vapor intrusion risk
Summary of Results: Test results of soil and groundwater samples collected from the site indicate the presence of petroleum compounds similar to what has been detected at the channel. The petroleum compound concentrations appear to be higher near the pipeline corridor that extends beneath the property from S. Perry Street, and near the pipeline corridor along E. Carson Street. These results suggest that certain petroleum impacted soil and groundwater beneath the property are from a pipeline source(s). Groundwater conditions at the former Active RV Site will continue to be monitored as part of the semi-annual monitoring program for the Dominguez Channel.
Soil vapor testing was performed on the former Active RV property to assess the potential health risk to indoor air. Test results indicated very low detections of petroleum compounds in soil vapor along the eastern property boundary with concentrations all well below the target California Human Health Screening Levels (CHHSLs) for residential indoor air. However, benzene was detected in the soil vapor samples collected near the western and northern sides of the onsite commercial building at concentrations exceeding the target CHHSLs for residential and commercial/industrial land use. Based on these detections, further assessment was conducted to determine if indoor air monitoring and mitigation might be required for the commercial building.
Phase 2: February – April 2012
– Conducted sub-slab vapor assessment of commercial building to assess potential indoor vapor intrusion risk
– Installed and sampled four additional groundwater monitoring wells
– Advanced one offsite Cone Penetrometer Test (CPT) boring with a Rapid Optical Screening Tool™ (ROST™) and collected soil and groundwater samples in the offsite residential neighborhood (these technologies help identify petroleum impacts at various depths)
– Further assessed soil conditions along the S. Perry Street pipeline corridor that extends beneath the
property
Summary of Results: Based on the results of soil vapor samples collected directly beneath the slab in the commercial building, potential health risks associated with vapor intrusion are acceptable under current
commercial/industrial land use conditions. The results of the offsite soil and groundwater sampling indicated that impacts to soil are minimal; the petroleum hydrocarbons in groundwater have extended into the offsite residential neighborhood, but at significantly lower concentrations than beneath the former Active RV site. The results of the supplemental soil sampling identified pockets of residual petroleum beneath the site.
Phase 3: October – November 2013
– Conducted GeoTrax Survey™ screening along the eastern boundary of the former Active RV site (GeoTrax
Survey™ is a non-invasive tool that allows one to better understand soil and groundwater impacts along the survey lines)
– Installed two additional offsite groundwater monitoring wells and conduct soil and groundwater sampling and analysis in the neighborhood east of the former Active RV property
Summary of Results: The results of the offsite soil and groundwater sampling in the neighborhood east of the farmer Active RV property indicate impacts to soil are minimal: the petroleum hydrocarbons in groundwater have extended into the residential neighborhood, but at significantly lower concentrations than beneath the former Active RV site.
The Geotrax Survey along the eastern boundary of the former Active RV property indicates possible isolated pockets of non-recoverable LNAPL.
Phase 4: November 2023– April 2024
-Conducted additional soil vapor sampling and sub-slab vapor sampling on the former Active RV property
– Advanced two offsite soil borings and conducted soil sampling and analysis in the neighborhood east of the former Active RV property.
-Installed two offsite groundwater monitoring wells and conducted soil and groundwater sampling and analysis in the neighborhood east of the former Active RV property.
Summary of Results: The results of the offsite soil and groundwater sampling in the neighborhood east of the farmer Active RV property indicate impacts to soil are minimal: the petroleum hydrocarbons in groundwater have extended into the residential neighborhood, but at significantly lower concentrations than beneath the former Active RV site.
