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STATE OF CALIFORNIA-Environmental P. on Agency PETE WILSON,Govemor <br /> CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD <br /> CENTRAL VALLEY REGION <br /> 3443 Routier Road,Suite A <br /> Sacramento,CA 95827-3098 --- <br /> PHONE:(916)255-3000 <br /> FAX:(916)255-3015 RECEi V' L. \ <br /> Mr. Randy Smith <br /> MAR 0 11996 29 February 1996 <br /> Southern Pacific Transportation Company ENVIRONMENTAL_ HEALTH <br /> One Market Plaza PERMIT/ SERVICES <br /> San Francisco, CA 94105 <br /> MODIFICATION OF SITE REMEDIATION PLAN,SOUTHERN PACIFIC TRANSPORTATION <br /> COMPANY, OLD TRACY YARD,SAN JOAQUIN COUNTY <br /> 1 have reviewed the 15 February 1996 letter prepared by Terranext regarding your proposed modification of the <br /> site remediation program for lead-impacted soils at the old Tracy yard. Southern Pacific Transportation <br /> Company(SPTCo)has decided to cancel the sale of the property for residential use. SPTCo holds that the <br /> remaining lead concentrations in the in-situ soils do not pose a threat to ground water. Instead of conducting <br /> additional off-site disposal, SPTCo proposes to treat the approximately 15,600 cubic yards of stockpiled soil to <br /> immobilize the lead, and then use the soil as backfill onsite. SPTCo proposes to analyze the treated soil for <br /> leachable lead using the waste extraction test(WET)with a citrate leach and proposes five mgLas the cleanup <br /> level. SPTCo also has agreed to install four temporary well below lead-impacted areas of the site to determine <br /> if the ground water is contaminated. Ground water monitoring data from two existing wells show no lead <br /> contamination in ground water. <br /> I agree that the concentrations of lead still in the in-situ soils at the yard probably do not pose a threat to ground <br /> water. This is based on the leachable concentrations found, ground water data obtained so far, and <br /> consideration of the historical use of the site. Treating the lead-contaminated soil and using it for backfill <br /> onsite is appropriate. However, the sampling protocol should include analyzing the soil by the WET using <br /> deionized water because it more closely represents natural leaching processes. Also, a cleanup level of one <br /> mg/1 will be required which equals the USEPA Drinking Water Action Level of 15 mg/1 multiplied by an <br /> environmental attenuation factor of 67. The four temporary wells should be sampled for at least three <br /> consecutive quarters. Once a future land use for the property is determined, a health risk assessment may be <br /> needed to determine if the residual contamination poses a risk for that use. <br /> The work plan is hereby approved on condition that the above directives are followed. By 27 March 1996, <br /> please submit a schedule for the proposed work including a date for submittal of a final remedial action report. <br /> Please contact me at least 48 hours prior to field work in case I wish to observe the work or obtain split samples. <br /> If you have any questions, you may call me at(916) 255-3077. <br /> Vv � <br /> J L M. WEISS <br /> Engineering Geologist <br /> JMW:jmw/lsb <br /> cc: Mr. Eric Garcia, Department of Toxic Substances Control, Sacramento <br /> San Joaquin County Department of Public Health Services, Stockton <br /> Mr. Dick Bateman, Terranext,Sacramento <br />