ARCHIVED REPORTS_XR0008796 - Laserfiche WebLink

Home Browse Search

Y PUBLIC HEALTH SERVICES SAN JOAQUIN COUNTY p S ENVIRONMENTAL HEALTH DIVISION y ` Karen Furst, M D , M PH , Health Officer 304 East Weber Avenue, Third Floor • Stockton, CA 95202 c4`'pp;ORN%P 2091468-3420 JOE ALDRIDGE JUL 11 2000 ULTRAMAR INC PO BOX 466 HANFORD CA 93232-0466 RE Former Beacon#419 SITE CODE 1756 2350 E Waterloo Rd RO# 00067 Stockton, CA.,95205 San Joaquin County Public Health Services, Environmental Health Division (PHS-EHD) has reviewed the "Addendum to Work Plan for Additional Subsurface Investigation" dated June 15, 2000 as subrrutted by Horizon Environmental Inc , on June 19, 2000 and has the following comments On October 7, 1997 Horizon submitted the September 30, 1997, "Work Plan for Additional Subsurface Investigation" PHS-EHD commented on the proposal in correspondence dated October 13, 1997 and required Ultramar to investigate the soil to the historical drought depth as well as evaluate other alternatives for remediation as required for the Feasibility Study PHS-EHD further required Ultramar to continue to delineate the lateral extent and vertical extent of contaminated soil if detected at this historical depth The "Report Additional Subsurface Investigation",dated February 17, 1999 submitted by Horizon on March 1, 1999 identified increasing petroleum concentrations in soil samples from"SB-6" at 88 feet below ground surface (` bgs) This trend in soul contamination at the historical depth was to be vertically defined and the lateral extent of the contamination at this depth was to be delineated also Wells "VW-1,VW-2,and AS-1" were installed in soil bonng SB-6 AS-1 was constructed with a screened interval from 64' to 69' bgs has consistently recorded very high levels of petroleum and alcohols in the groundwater samples No deeper well (screened interval} was installed to verify the groundwater quality at 88' bgs where contaminated soil remains The scope of work in the latest addexban proposes an additional subsurface investigation to 85' bgs, but not m the area of SB-6 A soilbonng (SB-10) is planned at approximately40 feet north of SB-6 and is to be dnlled to only 85' bgs The proposal included the collection of soil samples, a groundwater grab sample,and abandonment of the borehole MW 11 is proposed to be installed within five (5) feet of SB-10 with the screened interval from 35'to 55' bgs The locations of SB-10 and MW-1 1 do not provide for further vertical delineation at the area at SB-6 nor will they provide definition of the soil contamination found at 88'bgs in the SB-6 area and that may extend deeper Byhrruting the depth of SB-10 to only 85' bgs and limiting the screened interval m MW-11 to only fust water(and not at the depth of AS-1 where high levels of petroleum currently exist) you will not be laterally defining the contamination at the deeper areas of concern A Division of San Joaquin County Health Care Services