ARCHIVED REPORTS_XR0003971 - Laserfiche WebLink

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1 �^ September 3, 1992 ��S4 ACOR 1F Ms. Mary Ways SEP 4 8 9992 , San Joaquin County Public Health Services ENVIRONMENTAL HEALTH 1601 East Hazelton Avenue PERMIT/SERVICES $. . Stockton, California 95201 QUARTERLY STATUS REPORT FOR 429 WEST LOCKEFORD STREET, LODI, CALIFORNIA, SITE # 1354 Dear Ms. Meays: i y 4 On behalf of Mr. Mardee Kidd, Science & Engineering Analysis Corporation (SEACOR) is pleased to submit this status report summarizing activities conducted at the above referenced site from June 1, 1992 to August 28, 1992. During this time, SEACOR performed quarterly groundwater sampling of the existing groundwater monitoring well and continued operating a soil vapor extractions stem. k The details for each of these activities is provided below. r k f QUARTERLY GROUNDWATER MONITORING t On August 12, 1992, SEACOR collected a groundwater sample from monitoring well MW-1A_ Prior to sampling of the well, SEACOR measured the depth to groundwater in the well using an electronic water level indicator. Groundwater was measured at a depth of 46.83 feet below ground surface. Groundwater sampling was conducted in accordance with the procedures described in SEACOR's . technical report dated June 11, 1991. A copy of the water sample field data sheet is attached. G. The groundwater sample, identified as MW-1A-0892 was submitted to GTEL Environmental Laboratory (GTEL) of Concord, California for analysis of total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethylbenzene, and xylenes (BTEX) in accordance with EPA methods 8015, modified and 8020. The results of the current sampling event as well as historical groundwater quality data are presented in the attached Table 1. A complete laboratory report and chain-of- R custody record are also included as an attachment to this report. As shown in Table 1, the only analyte detected during the current sampling event was xylenes (total) „T at a concentration of 0.8 micrograms per liter (,ug/l) or parts per billion (ppb). These results are consistent with groundwater quality data from May 1992 and further indicate that fuel hydrocarbon ry ; concentrations in groundwater underlying the former underground storage tank have decreased to m non-detectable or trace levels. BTEX concentrations remain well below the State of California `x{ Maximum Contaminant Levels MCLS for drinking water. The non-detectable to trace Ievels of BTEX compounds reported during the last two quarterly groundwater monitoring events suggest that operation of the soil vapor extraction system may be enhancing volatilization of dissolved fuel hydrocarbons present in groundwater underlying the former underground storage tank. This conclusion will be evaluated further with additional groundwater f p monitoring data. The next quarterly groundwater monitoring event is scheduled for November 1992. r ' 100 Pine Street t: MAY.QSR Suite 2025 z . 50014-001-05 MKOI San Francisco, CA 94111 r (415)296-7877 (415)677-9694 FAX