WORK PLANS - Laserfiche WebLink

Home Browse Search

t...Iiepa's Car Wash (Pacific Avenue) Problem Assessment Report and Corrective Action Plan Page 10 i 6.1 .5 City Wells An approximately 14-inch well (XI ) was located on the east side of Gettysburg Place, north of Douglas Avenue, at the west entrance to the Lincoln shopping center. Approximately 300 feet south of X I , on the Gettysburg side of the shopping center, there is evidence of a new well installation in a fenced-off area with an installed electric power box; the surface conductor casing lying outside of the fencing was approximately 14 inches in diameter. No DWR records were found for these wells. 6.1 . 6 Neighbors The owner of the well on Marango Avenue (WI ) indicated that his four surrounding neighbors also had wells. 6. 1 .7 Old Farm Houses and Orchards The site radius is an area of homes from the 1950s that are interspersed with their predecessor of older rural farmhouses, farm land, and orchard. The owner of 756 Porter Avenue was contacted by telephone . She indicated that there probably had been a well located on her property before improvements; there had been an old farmhouse on her property. She thought that the hired contractor closed the well properly approximately 10 years ago. No DWR records exist for this location. There are two possible locations of wells on Pearl Avenue and one on Swain Road, both of which are old orchard and farmhouse sites . 6. 1 .8 LUST Sites Three Leaking Underground Storage Tank (LUST) sites are located within the 2,000-foot radius of the site_ 1 . A Regal gas station (Ll ) is located at 6425 Pacific Avenue, approximately 700 feet from the site to the northwest. 2, A Shell gas station (L2) is located at 6131 Pacific Avenue, approximately 500 feet south of the site. 3 . A Chevron gas station (L3 ) is located at 6633 Pacific Avenue, approximately 1 ,500 feet northwest of the site. Monitor wells were identified at the Regal and Chevron gas stations. In addition, several monitoring wells were identified in a commercial parking area on the southeast side of Benjamin Holt Drive and Gettysburg Place, — 6.2 TIER 1 RISK BASED CORRECTIVE ACTION EVALUATION A Tier 1 Risk Based Corrective Action Evaluation was conducted using the software RBCA Tool Kit for Chemical Releases, Version 1 .3 . Rased on the most recent soil investigation and the extensive soil vapor extraction activity, the evaluation assumed no remaining measurable soil contamination above the current groundwater elevation. Initial outputs of the software indicated greatest impacts to indoor air. Consequently, we used the highest input concentration for each constituent taken from the July 2002 sampling of the groundwater in the three soil vapor extraction wells adjacent to the on-site building (SV- 1 ) SV-2, and SV-3). Evaluation of the risks focused on benzene as the constituent of greatest concern. The Average Inhalation Exposure Concentration (vapor intrusion into on-site buildings) was calculated to be 0 .024 milligrams per cubic meter (mg/m') . This is in comparison to the Occupational Safety and Health Administration 8-hour time-weighted average limit of 3 .25 mg/ms, or the National Institute for Occupational Safety and Health R % 4/ CONDOR