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1 <br /> Jerry Lile <br /> ' December 10, 2003 <br /> Page 3 <br /> ' 2. The West Side Irrigation District feature depicted in Figure 2 is to be described in the <br /> text, including its uses. When and how will potential contamination in this area be <br /> addressed? <br /> ' 3. The text discusses pipelines located adjacent to the Union Pacific Railroad right-of- <br /> way, as compared to the maps depicting a Southern Pacffi Railroad feature. Please <br /> ' rectify to ensure transparency and consistency in the document. <br /> 4. Polynuclear Aromatic Hydrocarbons (PAHs) <br /> ' ai EPA Method 82TO SIM, as recommended by HERD for PAHs analyses was <br /> employed in the soil and groundwater Investigations. <br /> ' b. Detection limits were elevated for soil sample GB-3 from 7 ft bgs; benzo(a)pyrene <br /> may be present in soil at a risk of approximately 4 x 10-6, although not detected due <br /> to the elevated detection limits; the detection limit was 4 fold higher than the U.S. <br /> ' EPA Region IX Preliminary Remediation Goal (PRG)that corresponds to a risk of 1 <br /> x 10'6. <br /> c. Detection limits for groundwater analyses were 0.1 µg/l, as compared to the U.S. <br /> EPA Region IX PRG for benzo(a)pyrene in tap water, 0.0092 µg/I, which <br /> corresponds to a risk of 1 x 10 . Consequently, although benzo(a)pyrene was not <br /> detected in groundwater, it may be present at levels corresponding to risks in the <br /> ' range of 1 x 10-4. Similarly, other carcinogenic PAHs may be present in <br /> groundwater at risks in the 104 to 10'5 risk range, yet not detectable due to the <br /> restrictive sensitivity of the analytical method. <br /> 5. Metals <br /> ' a. Analyses for metals in soil and/or groundwater were not conducted and metals <br /> were not included in the screening risk evaluation. <br /> b. HERD previously reviewed numerous documents submitted by ChevronTexaco <br /> ' and addressed the issue of metals as chemicals of potential concern at OVP sites in <br /> a June 11, 2003 memorandum to Michael Pfister regarding the Gonzales property. <br /> Briefly, HERD's findings were as follow. Metals concentrations In crude oil vary, <br /> depending on geological and geochemical features at the source of the oil <br /> extraction. The 1993 Metcalf& Eddy publication cited is not specific to Central <br /> Valley crude, but rather is from a compilation of sources as published by <br /> International Agency for Research on Cancer(IARC). Data on metals <br /> concentrations in McMillan et al. (2001) only contain one sample from California. <br /> Data on metals concentrations in oil were also submitted in the form of analytical <br />