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2.5.2 Groundwater Assessment Data
<br /> Recent (February 2012) groundwater data for samples collected from A, B, C, and
<br /> D Zone wells located on the former Time Oil terminal are included in Stantec's First
<br /> Quarter 2012 Site Status, Groundwater Monitoring and Remedial Summary Report,
<br /> Stockton Terminals Technical Committee Facilities, Port of Stockton, Stockton,
<br /> California (Stantec, 2012). Samples were analyzed for TPH-g, TPH-d, BTEX, methyl
<br /> tert butyl ether (MTBE), di-isopropyl ether(DIPE), ethyl tert butyl ether(ETBE), tertiary
<br /> amyl methyl ether (TAME), tertiary butyl alcohol (TBA), methanol, ethanol,
<br /> 1,2-dichloroethane (1,2-DCA), ethylene dibromide (EDB), and naphthalene.
<br /> A Zone: There are currently 11 A Zone wells on the former Time Oil terminal site
<br /> (TO/T-2R, TO/T-3R, TO/T-5R, TO/R-2R, TO/R-3R, TO/R-5R, TO/R-6R, TO/MW-1,
<br /> TO/MW-2, TO-MW-3, and TO/WC-1S). Laboratory analytical results for the February
<br /> 2012 groundwater monitoring event reported benzene concentrations ranging from not
<br /> reported above the method reporting limit (<0.50)to 12,000 micrograms per liter (pg/L),
<br /> toluene ranging from not reported above the method reporting limit (<0.50) to 980 gg/L,
<br /> ethylbenzene ranging from not reported above the method reporting limit (<0.50) to
<br /> 1,200 µg/L, and total xylenes ranging from not reported above the method reporting limit
<br /> (<0.50) to 4,100 gg/L. TPH-g concentrations ranged from not reported above the method
<br /> reporting limit (<50) to 44,000 pg/L, and TPH-d concentrations ranged from 100 to
<br /> 160,000 µg/L. MTBE concentrations ranged from not reported above the method
<br /> reporting limit (<0.50) to 7,400 gg/L, and TBA concentrations ranged from not reported
<br /> above the method reporting limit (<0.50) to 870 pg/L. Other oxygenates and fuel
<br /> additives reported in the sample collected from well TONT-3R included DIPE (estimated
<br /> at 0.14 pg/L), ETBE (0.66 µg/L), and TAME (1.8 gg/L). Naphthalene concentrations
<br /> ranged from not reported above the method reporting limit(<0.50)to 710 µg/L.
<br /> B Zone: There are two B Zone wells on the former Time Oil terminal site, TO/WC-1M,
<br /> located in the north-central portion of the site, and TO/WC-213, located in the
<br /> southwestern portion of the property. Laboratory analytical results for the February 2012
<br /> groundwater monitoring event reported benzene at an estimated concentration of
<br /> 0.27 pg/L, TPH-d at 190 µg/L, and MTBE at 0.78 gg/L in the sample collected from well
<br /> TO/WC-1M. In the groundwater sample collected from well TO/WC-213, benzene
<br /> (1,400 gg/L),toluene (2 µg/L), ethylbenzene (estimated concentration of 0.94 µg/L), total
<br /> xylenes (12 Itg/L), TPH-g (3,300 pg/L), TPH-d (4,700 µg/L), MTBE (420 pg/L), TBA
<br /> (110 pg/L), ethanol (estimated concentration of 6.5 µg/L), 1,2-DCA (estimated
<br /> concentration of 0.47 pg/L), and naphthalene (4.5 µg/L)were reported.
<br /> C Zone: There is one C Zone well installed at the former Time Oil terminal,
<br /> TO/WC-1C, located in the north-central portion of the property. Laboratory analytical
<br /> results for the February 2012 groundwater monitoring event reported benzene at an
<br /> estimated concentration of 0.44 pg/L, TPH-d at 230 pg/L, MTBE at an estimated
<br /> concentration of 0.22 gg/L, and naphthalene at an estimated concentration of 0.48 µg/L.
<br /> Site Characterization Work Plan,Final, May 18,2012
<br /> 1007-012.002 2-9
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