Laserfiche WebLink
Metadata
Document management portal powered by Laserfiche WebLink 9 © 1998-2015 Laserfiche. All rights reserved.
Brown and Caldwell <br /> BG <br /> Consultants <br /> ' 723 S Sl,eei <br /> Sacramento ,+ t7 ,-r2-+► <br /> Caldornia 95814 7092 <br /> (916)444 0123Ail " <br /> FAX 19161 444 8437 *+ '� <br /> Z � t�9Z <br /> February 24, 1992 FE� <br /> ENVIRpNt,4EN rAL HtAL1'H <br /> PERMIT/SEROCES <br /> Mr Chuck Carmel <br /> ARCO Products Company <br /> Post Office Box 5811 <br /> San Mateo, California 94402 017-5690-04/1 <br /> Subject 1991 Fourth Quarterly Report for ARCO Station 2133, <br /> 2908 Benjamin Holt Drive, Stockton, California <br /> Dear Mr Carmel <br /> This report presents the fourth quarterly water levels and analytical results of groundwater <br /> sampling performed at ARCO Products Company (ARCO) Station 2133 located at 2908 <br /> Benjamin Holt Drive in Stockton, Califorrua The work was performed on October 8 and 9, <br /> 1991, under Task Order 2133-91-5A There are fifteen on-site wells E-2 through E-12, <br /> PR-1, PR-2, BHD-1, and BHD-2 (Figure 1) Although all of the wells were scheduled to be <br /> sampled during this sampling event, eight (E-3, E-4, E-5, E-6, E-7, E-9, PR-2, and BHD-2) <br /> of the fifteen wells were dry or did not recharge enough for sampling after purging <br /> Therefore, a total of six wells were sampled The most likely cause of some of the wells near <br /> the extraction well going dry is the operation of the groundwater extraction system <br /> Field and Analytical Methods <br /> Brown and Caldwell personnel measured depth-to-water levels, supervised purging of each <br /> well, and collected groundwater samples at the site Refer to Exhibit A for detailed field <br /> methods description A copy of the field notes containing the pH, electrical conductivity, and <br /> temperature readings is included as Exhibit B <br /> All groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPH-G) <br /> and benzene, ethylbenzene, toluene, and xylenes (BETX) by Modified U S Environmental <br /> Protection Agency Method 8015/5030/8020 In addition, groundwater from sample wells E-8 <br /> and BHD-1 were analyzed for nitrates by EPA Method 3000 <br /> Results <br /> The groundwater extraction system at this site has been in operation since .lune 1991 Since <br /> the start-up, the system has been pumping at a rate of approximately 10 1 ggillons per minute <br /> (gpm) The groundwater extraction system has influenced the groundwater flow pattern <br /> locally, as shown on Figure 1 In September 1991, the pumping rate -%vas reduced to <br /> approximately 5 5 gpm because too large of an area was being influenced when the pumping <br /> rate was 10 1 gpm Table 1 (Exhibit C) presents the water-level data for this site in tabular <br /> form, and Table 2 (Exhibit D) presents historical flow direction and gradient data for this site <br /> 569ONRF.PORTs\OCT91 QrRPFr <br />