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PUBLIC HEALTH SERVYCES <br /> SAN JOAQUIN COUNTY <br /> ENVIRONMENTAL HEALTH DIVISION H ; <br /> Ernest M. Fujimoto, M. D., M.P.H., Acting Health Officer <br /> 304 East Weber Avenue, Third Floor • Stockton, CA 95202 . ``R ' �►`! <br /> 2091468-3420 <br /> JONATHAN MARLOWE JUN 2 5 07 <br /> MARLOWE PROPERTIES <br /> PO SOX 150211 <br /> SAN RAFAEL CA 94915-4211 <br /> Re: Marlowe Property Site Code: 1828 <br /> 4648 Waterloo Road <br /> Stockton CA 95215 <br /> San Joaquin County Public Health Services, Environmental Health Division has completed review of the following <br /> reports that were prepared by Advanced GeoEnvironmental: <br /> "Revised Corrective Action Plan-January 1997"dated February 18, 1997; and <br /> "Quarterly Report- December 1996"dated February 19, 1997;and <br /> "Quarterly Report-March 1997"dated May 8, 1997. <br /> The December Quarterly Report included the results of soil sampling conducted during the installation of <br /> monitoring wells, MW5 and MW6. No petroleum hydrocarbons were detected in any of the soil samples which <br /> were submitted for analysis. Two soil samples were submitted for total organic carbon analysis and one soil sample <br /> was submitted for average permeability and percent porosity. Please submit the chain of custody for the sample <br /> submitted to Cooper Testing Lab since the report failed to include this chain of custody. <br /> The March quarterly report included the results of the March 14, 1997 groundwater sampling event. The depth to <br /> water ranged from 60.65 to 61.92 feet below ground surface(bgs). Since this level is significantly above the <br /> screened interval of MW2, MW3 and MW4(from 80 to 110 feet bgs)groundwater samples were not collected from <br /> these wells. The groundwater samples collected from MW I,MWS, MW6 and VW1 continue to evidence <br /> groundwater contamination up to 5,600 ppb TPH-gas and 40 ppb benzene. Please include the halogenated volatile <br /> organic compounds that have been detected in the petroleum hydrocarbon contaminants summary table. <br /> There has been considerable fluctuation in the concentrations of petroleum hydrocarbons that have been detected at <br /> this site primarily due to the dramatic fluctuations of the groundwater level. Groundwater was observed as low as <br /> 91.90 feet bgs on January 8, 1993 and as high as 60.65 feet bgs on March 14, 1996.The depth to water <br /> measurements should be included on summary tables even if groundwater samples are not submitted for analysis. <br /> The revised corrective action plan(CAP)failed to include an inventory of all the nearby domestic wells. PHS/EHD <br /> performed a limited well survey in association with the detection of volatile organic compounds in the monitoring <br /> wells and the former drinking water well which served the commercial businesses on site. A map illustrating nearby <br /> well locations and a summary table of well construction information should be submitted as addendum to the <br /> revised CAP. <br /> The revised CAP indicated that approximately 220 cubic yards of contaminated soil remains: 58 cubic yards <br /> between 15 and 30 feet bgs and 160 cubic yards between 30 and 45 feet bgs. The calculation of the remaining <br /> petroleum hydrocarbon mass utilized the assumptions that the average concentration of TPH-gas contamination was <br /> 14,000 ppm for the soil between 15 and 30 feet bgs and 1.1 ppm for the soil between 30 and 45 feet bgs. <br /> The revised CAP failed to include the construction costs associated with the proposed vapor extraction system, but <br /> the maintenance costs were estimated to range from$12,000 to 530,000 per year. It is unclear how much a vapor <br /> extraction system would cost to install and to subsequently monitor with additional soil sampling. <br /> A Division of San Joaquin County Health Care Services <br />