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V. Local Agency Representative Data <br /> Name: Donna Heran, REHS Title: Director <br /> Sign e: Date: July 30, 2013 <br /> VI. Central Valley Regional Water Quality Control Board RB Notification <br /> Date Submitted to RB: 05 March 2013 Response Date: 22 March 2013 <br /> RB Staff: James L.L. Barton, PG Response: Concurrence <br /> Title: Engineering Geologist <br /> VII. Additional Comments, Data, etc. <br /> There is some discrepancy in records on UST sizes and contents; those reported above are from EHD UST Unit records; <br />�i. other records (i.e. manifests, tables, field notes, etc) gives saes and contents as follows: tank 391800-07 — 2500-galllon; <br /> tank 39-1800-08— 1,000-gallon waste oil; tank 39-.1.800-10-500-gallon. <br /> Residual contaminant-mass estimate in 2001 was 3,987 pounds of TPHg and 40,576 pounds of TPHd. A SESOIL model <br /> in to groundwater and an AT123D model predicted no impact to down gradient receptors. <br /> predicted no contaminant load g <br /> p <br /> 9 , <br /> based on benzene excluding high data from `hot spot area (UST, line <br /> Fate and Transport model in RISC5 Workbench, 9 9 <br /> p � <br /> sample, MW-5 and VW-11) found the exposure point concentration to be 3.69 x 10-3 (no units provided) and non- <br /> carcinogenetic was 5.25 x 10-3 (no units); exposure point was an indoor worker. Consultant states that carcinogenetic risk is <br /> less than 1x10-6 and non-carcinogenetic risk was 0.004. Human health risk assessment was not performed for.a <br /> construction worker or resident as the site is commercial and paved. Consultant predicts achievement of WQOs in 2020 (7 <br /> years) for 1,2-DCA, the only contaminant currently impacting groundwater. <br /> The benzene and ethylbenzene concentrations in shallow soil were evaluated against the LTCP risk numbers by the EHD. <br /> There is a paucity of 5-ft data and limited 10-ft data. The 5-ft data for HA-1, B7-5, B-18-5, B20-5, VEW1-5, VEW2-5, <br /> VEW3-5 and MW5-5.pass for residential and commercial use; soil data from 10-ft samples passed for both concerns except <br /> benzene in MW5-10 and ethylbenzene in MW5-10 and VW1-10,do not pass either residential concern. <br /> The State Water Board Cleanup Fund Staff has recommended site closure. <br /> This document and the related Case Closure Letter shall be retained by the lead agency as part of the official site file. <br /> i <br /> -Page 3 <br />