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1 � • <br /> 1 I <br /> \- Department of Toxic Substances Control <br /> ' Edwin F. Lowry, Director <br /> Terry Tamminen 8800 Cal Center Drive Amold Schwarzenegger <br /> Agency Secretary Sacramento, California 95826-3200 Govema <br /> ' CaIJEPA <br /> MEMORANDUM <br /> ' TO: Jerry Lile <br /> Project Manager <br /> Northern California Site Mitigation Branch <br /> 8800 Cal Center Drive, 2nd Floor <br /> Sacramento, CA 95826-3200 <br /> FROM: Karen W. Di,3iasio, Ph.D: w 6, � U - <br /> Staff Toxicologist <br /> Science, Pollution Prevention and Technology Program <br /> Human and Ecological Risk Division <br /> DATE: December 10, 2003 <br /> ' SUBJECT: OLD VALLEY PIPELINE- LAURELBROOK (SURLAND HOMES) <br /> PCA Code: 12045 Site Code: 101556 WP: 11 <br /> ' BACKGROUND <br /> ' The Human and Ecological Risk Division (HERD)was requested to provide toxicology and <br /> risk assessment support for the screening-level health risk assessment for the Laurelbrook <br /> (Sudand Homes) property by the Site Mitigation Program at the Region 1 Sacramento <br /> ' Office. The property is located in Tracy, California. Chevron's Old Valley Pipeline (OVP) <br /> was located adjacent to the Union Pacific Railroad right-of-way along the southern <br /> boundary of the current Surland Homes residential development. Also present in the right- <br /> of-way was the former Associated Pipe Line (APL) Company's pipeline which was <br /> subsequently acquired by ChevronTexaco. ChevronTexaco and the property owner <br /> seek a risk-based no further action determination of the site under DTSC's Voluntary <br /> Cleanup Program. The Regional Water Quality Control Board (RWQCB) is the lead <br /> ' regulatory agency for oversight of OVP sites. <br /> The former OVP transported heavy petroleum (crude and fuel oil)from the early 1900's <br /> to the 1950's. The former APL transported heavy crude from the early 1900's to the <br /> 1970's when it was decommissioned. Degraded crude or Bunker C :oil has been <br /> observed in the sub-surface soil along the OVP. Affected soil has been reportedly <br /> observed from 4.5 to 13.5 ft below ground surface (bgs), extending below the current <br /> water table elevation which is 5 to 7 ft bgs. Groundwater flows generally to the north- <br /> ' ® Printed on Recycled Paper <br />