Laserfiche WebLink
Date: October 27,2003 <br /> Quarter: 3'd Quarter,2003 <br /> • ARCO QUARTERLY GROUNDWATER MONITORING REPORT <br /> Facility No.: 5450 <br /> Address: 1617 Wesi Fremont Street, Stockton, CA <br /> ARCO Environmental Engineer: Paul Supple _ <br /> Consulting Co./Contact Person: URSNernon Elarth <br /> Consultant Project No.: 38466255.OL058 <br /> Primary Agency/Regulatory ID No.: San Joaquin County Environmental Health Dept. (SJCEHD) <br /> Assembly Bill 681 Status: Property owned_by Atlantic Richfield Company <br /> WORK PERFORMED THIS QUARTER (Third 2003): <br /> 1. Performed quarterly groundwater monitoring and sampling. <br /> 2. Prepared and submitted quarterly groundwater monitoring report. <br /> WORK PROPOSED FOR NEXT QUARTER (Fourth 2003): <br /> 1. Perform quarterly groundwater monitoring and sampling. <br /> 2. Prepare and submit quarterly groundwater monitoring report. <br /> QUARTERLY RESULTS SUMMARY (Third 2003): <br /> • Current Phase of Project: Monitoring <br /> Frequency of Groundwater Sampling: MW-2 through MW-4 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: 11.23—11.30 feet below ground surface <br /> Groundwater Flow and Gradient: Northwest G 0.003 ft/ft <br /> ANALYTICAL DATA REVIEW: <br /> Based on the review of the analytical and hardcopy data (chain-of-custody records,blanks,dilutions, holding times, <br /> LCS/LCSD results, MS/MSD results, and surrogate recoveries), the data are acceptable as reported by the <br /> laboratory. <br /> DISCUSSION: <br /> Total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene,ethylbenzene, and total xylenes (BTEX) were <br /> reported as below laboratory detection limits in all groundwater samples collected from site wells. Methyl ter -butyl <br /> ether (MtBE) was detected in MW-2 and MW-4 at concentrations of 18 and 1.5 micrograms per liter (lag/L), <br /> respectively. A decreasing trend in MtBE concentrations for MW-2, a slight increase in concentration for MW-4 <br /> relative to the previous sampling events. No other analytes were detected above method detection limits. <br /> Groundwater elevations in site wells decreased relative to the previous quarter. The approximate groundwater flow <br /> direction was to the northwest at an average gradient of 0.003 ft/ft. <br /> This report is based on data,site conditions,and other information that are generally applicable as of the date of the <br /> report,and the conclusions and recommendations herein are therefore applicable only to that time frame. <br /> KAWpr cmUS BP ARC0054501Qumerlyl3 QTR 03 5450 GWMR 3QW&c Page 1 <br />