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T <br /> V. EUMUNU G. BHVWN JH. <br /> PE�jy EIV t��� • GOVENNOH <br /> ■V/ /�, <br /> c A L I r O R H 1 A MATTHEW nODRIOUEZ <br /> ARY Epfl <br /> WaterBoards 'FEB 10 2M ENVIAOENVIPpNMfiNTAt PP0T6CTION <br /> Central Valley Regional Water Quality Control Board ENVaRONMENTALHEALTH <br /> a <br /> 'PERMIT/SERVICES <br /> f�9� <br /> 7 February 2014 <br /> Michael Oliphant <br /> Chevron Environmental Management Company <br /> P.O. Box 6012 <br /> San Ramon, CA 94583 <br /> HUMAN HEALTH AND ECOLOGICAL SCREENING EVALUATION (HHESE), TIDEWATER <br /> ASSOCIATED OIL COMPANY (TAOC) 6T" STREET TRACY RAIL YARD PROPERTY, TRACY, <br /> SAN JOAQUIN COUNTY <br /> Central Valley Regional Water Quality Control Board staff (Staff) have reviewed the subject HHESE <br /> submitted on behalf of Chevron Environmental Management Company (Chevron) by AMEC <br /> Environment & Infrastructure, Inc. (AMEC). Staff's comments are provided in the enclosed <br /> memorandum. <br /> The HHESE, dated 30 September 2013 concluded that there is minimal risk exposure to human <br /> health as well as the environment from the historical crude oil pipeline releases found within <br /> investigative area operable unit 2 (OU-2). However, within OU-5, AMEC's report estimated that <br /> based on the findings, the cancer risk was above the acceptable de minimus target level of one in <br /> one million, i.e., 1 E-06. However, the report indicated that if exposure is re-evaluated without using <br /> analytical results from boring TRY-29, the non-cancer risk and cancer risk estimate for each <br /> receptor evaluated were well below the target levels of 1 and 1 E-06, respectively. The report states <br /> that site-related chemicals are unlikely to result in unacceptable non-cancer health hazards of <br /> cancer risk if future exposure to soil at boring TRY-29 is mitigated. <br /> Based on our review, Staff finds the following: <br /> • Preparation and submission of the soil and groundwater management plan should be <br /> delayed until after the conditions identified at boring TRY-29 are resolved either by: 1) an <br /> acceptable plan for mitigation at boring TRY-29 is addressed/approved, or 2) removal of the <br /> PAH affected soil at boring TRY-29 is completed. <br /> • Regardless of which path forward is chosen, an amendment to the September 2013 HHESE <br /> will be required to reflect conditions once mitigation is conducted or the PAH affected soil is <br /> removed. <br /> KAr+I E. LONOLEY SLD, P.E.,CnAM I PAMELA C. CnGEOON P,fi., BGEE, mou7lvc Oman <br /> 1685 c Street,Fresno.CA 93706 1 www,waierboarde.ca.gov/centralvalley <br /> Y.X RECYCLED PA"" <br />