Laserfiche WebLink
Date April 29,2002 <br /> • Quarter 1Q02 <br /> FORMER ATLANTIC RICHFIELD COMPANY QUARTERLY GROUNDWATER <br /> MONITORING REPORT <br /> Facility No 4493 Address 205 N Center St,Stockton,CA <br /> Environmental Engineer Paul Supple <br /> Consulting Co/Contact Person SECOR/Rusty Benkosky <br /> Consultant Project No 77BP 54493 00 0701 <br /> Primary Agency/Regulatory ID No San Joaquin County Environmental Health Department(SJCEHD) <br /> Assembly Bill 681 Status Property owned by Cit of Stockton <br /> WORK PERFORMED THIS QUARTER (First Quarter- 2002): <br /> 1 Performed quarterly groundwater monitoring and sampling <br /> 2 Prepared and submitted quarterly groundwater monitoring report <br /> 3 Prepared and submitted"Addendum#2 to Work Plan for Installation of Multi-Completion Wells, Dated <br /> November 16, 2000"on March 22,2002 <br /> WORK PROPOSED FOR NEXT QUARTER (Second Quarter - 2002): <br /> . 1 Conduct quarterly groundwater monitoring and sampling <br /> 2 Prepare and submit quarterly groundwater monitoring report <br /> 3 Install multi-casing wells <br /> 4 Prepare and submit work plan for additional lateral assessment <br /> QUAR'T`ERLY RESULTS SUMMARY <br /> Current Phase of Project Monitoring/Assessment <br /> Frequency of Groundwater Sampling MW-1 through MW-7 sampled quarterly <br /> Frequency of Groundwater Monitoring Quarterly <br /> Is Free Product(FP)Present Onsite No <br /> Current Remediation Techniques Natural attenuation <br /> Approximate Depth to Groundwater 13 3/4 to 18 3/a ft <br /> Groundwater Flow and Gradient East @ 0 022 ft/ft <br /> DISCUSSION: <br /> Total petroleum hydrocarbons as gasoline(TPHg)were reported in three of the seven monitoring wells sampled this <br /> quarter at concentrations ranging from 370 ppb(MW-5) to 960 ppb(MW-4) Benzene,analyzed by EPA Method <br /> 8260B,was reported in four of the seven wells at concentrations ranging from 0 62 ppb(MW-1)to 27 ppb(MW-5) <br /> Methyl tert-butyl ether(MtBE),analyzed using EPA Method 8260B,was reported in all seven wells analyzed this <br /> . quarter at concentrations ranging from 0 66 ppb (MW-6)to 200 ppb(MW-5) Tert-butyl alcohol(TBA) was <br /> detected in two wells MW-4 at 33 ppb and MW-5 at 23 ppb 1,2-dichloroethane(1,2-DCA)was detected in well <br /> MW-5 at a concentration of 0 77 ppb,this is the first detection of 1,2-DCA at this site Other fuel oxygenates were <br /> not detected in the wells,however,some volatile orgaimc compounds were detected at low concentrations(Table 3) <br /> Chemical concentrations were generally consistent with previous quarterly data with the following exceptions <br />