Laserfiche WebLink
Date: October 31, 2000 <br /> Quarter: 3Q00 <br /> ARCO QUARTERLY GROUNDWATER MONITORING REPORT <br /> Facility No.: 4493 Address: 205 North Center Street,Stockton,CA <br /> ARCO Environmental Engineer: Paul Supple <br /> Consulting Co./Contact Person: SECOR International Incorporated/Rusty Benkosky <br /> Consultant Project No.: 077.41907.703 <br /> Primary Agency/Regulatory ID No.: San Joaquin County Environmental Health Department <br /> Assembly Bill 681 Status: Property Owned by City of Stockton <br /> WORK PERFORMED THIS QUARTER (Third Quarter—2000): <br /> 1. Conducted quarterly groundwater monitoring and sampling. <br /> 2. Prepared and submitted quarterly groundwater monitoring report. <br /> 3. Prepared and submitted site assessment report. <br /> WORK PROPOSED FOR NEXT QUARTER (Fourth Quarter—2000): <br /> 1. Conduct quarterly groundwater monitoring and sampling. <br /> 2. Prepare and submit quarterly groundwater monitoring report. <br /> 3. Prepare and submit work plan for additional site assessment. <br /> QUARTERLY RESULTS SUMMARY <br /> Current Phase of Project: Monitoring/Assessment <br /> Frequency of Groundwater Sampling: MW-1 through MW-7 are sampled quarterly. <br /> Frequency of Groundwater Monitoring: Quarterly <br /> Is Free Product(FP)Present On-Site: No <br /> Current Remediation Techniques: Natural Attenuation <br /> Approximate Depth to Groundwater: 12.5 to 14.5 <br /> Groundwater Gradient: Southeast 0 0.012 <br /> DISCUSSION: <br /> TPHg was reported in three of the seven groundwater monitoring wells sampled this quarter at concentrations ranging <br /> from 75.7 ppb(MW-3)to 3,460 ppb(MW-4). Benzene was reported in five of the seven wells sampled this quarter at <br /> concentrations ranging from 0.512 ppb(MW-3)to 234 ppb(MW-4). MtBE(EPA Method 8260) was reported in three <br /> wells sampled this quarter at concentrations ranging from 102 ppb(MW-6)to 1,710 ppb(MW-4). Trichloroethene <br /> (TCE) was reported in three of the seven wells sampled this quarter at a maximum concentration of 185 ppb(MW-1). <br /> Cis-1,2-Dichloroethene was reported in five of the seven wells sampled at concentrations ranging from 3.40(MW-5) <br /> to 361 ppb(MW-1). Groundwater elevations across the site decreased by an average of.63 feet this quarter,and flow <br /> was to the southeast with a hydraulic gradient of approximately 0.0 12 ft/ft. <br />