ARCHIVED REPORTS_DRAFT - PHASE I REMEDIAL INVESTIGATION REPORT

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Kennedy/Jenks Consultants • (500-gallon unleaded gasoline and 1,000-gallon diesel), which were removed in 1989 (Industrial Compliance [IC] 1992a). ' As part of the UST removal, 16 cubic yards (cy) of soil containing petroleum hydrocarbons were excavated and transported offsite for disposal. Three groundwater monitoring wells, designated MW-1(RMC), MW-2(RMC) and MW-3(RMC), were installed in this southeastern corner of OU-1 and sampled for three consecutive calendar quarters. Samples were analyzed for total petroleum hydrocarbons (TPH) as gasoline and diesel (TPHg and TPHd) and benzene, toluene, ethylbenzene, and xylenes (BTEX). No analytes were detected above laboratory reporting limits, and the wells were reportedly abandoned in late 1992 (Terranext [formerly IC] 1996a). Past reports do not indicate how the wells were abandoned. In 1992, a Phase 11 Site Investigation of the OU-1 area (Phase II) was conducted to address applicable findings from the initial Level One Environmental Site Investigation for the Railyard (IC 1992a). The Phase II Investigation entailed advancing six borings (MW-1, MW-2 and B1 through 134) and completing two borings (MW-1 and MW-2) as groundwater monitoring wells. Well MW-1 was located in the northern-central portion of OU-1, and Well MW-2 was located in the approximate location of the former refuse pit. Soil samples were collected from the borings and analyzed for metals; polynuclear aromatic hydrocarbons (PAHs); TPHg and TPHd; BTEX; and volatile organic compounds (VOCs). Selected samples, including those with total lead concentrations greater than 50 milligrams per �• kilogram (mg/kg), were also analyzed for California Code of Regulations (CCR) Title 22 metals. Groundwater samples were analyzed for TPHg and TPHd, BTEX and VOCs. Results are highlighted below, and summary tables from the previous report were reproduced in Appendices D and E of the RI Work Plan: ' • Lead was detected in soil samples at concentrations ranging from 19 to 2,100 mg/kg. The highest concentration was found in a sample from boring MW-1, located adjacent to ' the railroad tracks along Sixth Street, at a depth of 0.5 feet below ground surface (bgs). Other metals were also detected. • The highest soluble lead concentration among these samples, 110 milligrams per liter (mg/1), correlated with the highest total lead concentration, from boring MW-1. • PAHs (fluoranthene and pyrene) were detectable at trace concentrations (up to 0.3 mg/kg) in one soil sample, from boring MW-1. • TPH was not detected in any of the soil samples. • VOCs (toluene and xylenes) were detected at trace concentrations (up to 0.01 mg/kg) in samples from one boring, MW-2, which was adjacent to the former refuse pit in apparent fill material. No VOCs were detected in soil samples from underlying native soil. • None of the target analytes were detectable in the groundwater samples. Oil was not detected in soil samples collected adjacent to the oil-filled sump previously identified in the Engeo Level One Environmental Site Investigation. The sump did not contain oil or evidence of oil residual at the time of this investigation; the sump appeared to be a utility access box. DRAFT Phase I Remedial Investigation Report Page 3 Former Tracy Railyard, Tracy, California g:lis-groupkadminl obk0510565777.18_uprr109-reportslri rptltext.doc