SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

California Regional Water Quality Control Board 'w ' k.�% Central Valley Region Robert Schneider,Chair Gray Davis Winston H.Hickox Secretaryfor Sacramento Main Office Governor Environmental Internet Address: http://www.swrcb.ca.gov/rwgcb5 Protection 3443 Routier Road,Suite A,Sacramento,California 95827-3003 e ' Phone(916)255-3000•FAX(916)255-3015 JUL 19 2001 ENVIRONMENT HEAL I'H 18 July 2001 RMIT/SERVICES Tony Arnaiz Central Valley Construction " PO Box 830 Lathrop, CA 95330 REVIEW PROPOSAL FOR CHARACTERIZATION/REMEDIATION, CENTRAL VALLEY CONSTRUCTION, 12565 SOUTH MANTHEY ROAD,LATHROP,SANJOAQUIN COUNTY I reviewed the 26 June 1998 Tank Closure and Site Investigation Report submitted by Geological Technics Incorporated(GTI), the 7 May 2001 Phase II Environmental Assessment, and the 11 June 2001 Characterization /Remediation Proposal, Former USTArea (Workplan), both submitted by John Cummings &Associates (JCA) for the South Manthey Road site. The site is a former poultry and egg farm. In August 1989, four underground storage tanks (USTs) (two 1,000-gallon, and two 10,000-gallon) were reportedly removed from the site under the direction of San Joaquin County Environmental Health Division (County). In May 1998, GTI completed an investigation of the four USTs, the former 10,000-gallon above ground storage tank(AGT), an on-site domestic well(DW-1),retention pond soils, and a sump. GTI identified soil and groundwater contamination at 10 feet below the former 10,000-gallon USTs and at 10 feet below the former AGT. MtBE was identified in one soil sample at 0.0082 milligrams per kilogram(mg/kg)below one of the former 1,000-gallon USTs. Low concentrations of gasoline and BTEX constituents were identified in a water sample collected from the domestic well, which is located in close proximity to the former USTs and AGT. Concentrations of oil as total extractable petroleum hydrocarbons (TEPH)were also identified in retention pond soil samples, and from a water sample taken from the sump. As a follow-up to GTI's investigation, JCA re-sampled DW-1 in January 2001, and TPH and BTEX constituents were not detected. In April 2001, JCA completed trenches at the former USTs and AGT areas using a backhoe. Soil contamination was identified at 14 to 18 feet at the former USTs, where first groundwater was encountered. JCA reported a 2.5-foot thick sand lens starting at 15 feet that showed high concentrations of TPHd and TPHg. A groundwater grab sample collected at 18 feet in the open trench showed TPHd at 21,000 micrograms per liter (µg/1), and TPHg at 30,000 µg/1. MtBE and other oxygenates were non-detect at<20 to<100 µg/1. TPHd contamination was identified in soil to a depth of 3 feet at the former AGT area. California Environmental Protection Agency �a Recycled Paper The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. For a list of simple ways you can reduce demand and cut your energy costs,see our Web-site at http://www.swrcb.ca.gov/rwgcb5