WORK PLANS - Laserfiche WebLink

Home Browse Search

ATC Associates Inc. 1117 Lone Palm Avenue, Suite B (: Modesto,California 95351 VATC 209-579-2221 ASSOCIATES I N C. fax:209-579-2225 The EHD issued a letter to Ms. Lolly Bozzano on September 11, 2003 and concluded that due to the continuing presence of TPHg, and BTEX in groundwater samples collected from monitoring well MWA and the presence of 1,2-DCA in groundwater samples collected from wells MWA and MW-3, further investigation of the site is warranted. Additionally, the EHD reviewed the Closure Report for the site prepared in 2001 by ATC and discussed the contents with the RWQCB. The RWQCB felt that the mass of contamination remaining in the soil was higher than the mass calculated in the report. They also thought that the feasibility of vapor extraction should be evaluated to remediate the contamination remaining in the soil that could continue to be a source of contaminant impact to groundwater. Based on their review, the EHD requested a work plan to investigate the lateral and vertical extent of the contamination at the site and to evaluate remedial alternatives for cleanup of the site. ATC's Workplan for Additional Subsurface Investigation at Three Palms Grocery located at 6732 East Highway 88, Stockton, California was approved by EHD on March 11, 2004. On March 24, 25, and 26, and May 20, 2004, three soil borings (GPI, GP2 and GP3) were advanced at the site in the vicinity of the former USTs to evaluate the lateral extent of petroleum affected soil and groundwater. On March 29 and April 2, 2004, two CPT borings (CPT1 and CPT2) were advanced at the site in the vicinity of the former USTs to evaluate the vertical extent of petroleum affected soil and groundwater. The GP and CPT borings are discussed in ATC's Supplemental Subsurface Investigation at Three Palms Grocery,dated October 18,2004. On August 30 and 31, 2005 and September 8 and 21, 2005, five hollow-stem soil borings were advanced at the site to further evaluate the extent of impacted soil in the vadose zone and groundwater. Three of the borings were completed as vapor extraction wells (VW1, VW2 and VW3), and two were completed as groundwater monitoring wells (MW4 and MW5). All field activities were performed in accordance with ATC's Workplan for Additional Subsurface Investigation at Three Palms Grocery located at 6732 East Highway 88, Stockton, California, dated May 2, 2005 and ATC's Addendum to Workplan for Additional Subsurface Investigation for 6732 East Highway 88, Stockton, California, dated June 27,2005. On November 16 and 17, 2005, three limited duration vapor extraction tests were conducted at the site. The installation of the vapor extraction wells, monitoring wells MW4 and MW5, and the procedures and results of the vapor extraction test are dicussed in ATC's Summary of Additional Subsurface Investigation and Vapor Extraction Testing Report, dated June 22, 2006. sA14885\workp1ans\wkp1n 11-20-06.doc 3