Laserfiche WebLink
y �✓ <br /> First Semiannual 2012 Groundwater Monitoring Report <br /> Former Texaco Service Station <br /> ` Chevron Site ID 309075 <br /> June 21, 2012 <br /> V <br /> The groundwater samples collected from the site monitoring well network did not contain <br /> concentrations of toluene, ethylbenzene, total xylenes, MTBE, DIPE, ETRE, TAME, EDB, <br /> ethanol, and methanol or above their respective laboratory MDL. <br /> 5.1.3 Remediation System Updates <br /> A remedial system is not associated with the site. <br /> 5.1.4 Plume Stability <br /> V <br /> Data gathered during the semiannual monitoring and sampling event indicates that the plume <br /> is stable. <br /> Dissolved TPH-MO Distribution <br /> Concentrations of TPH-MO with SGC were detected above the laboratory MDL in the <br /> groundwater samples collected from site monitoring wells MW-2, MW-5, MW-6, and MW-6D. <br /> hissolved TPH-DRO Distribution <br /> Concentrations of TPH-DRO with SGC was detected above the laboratory MDL in the <br /> groundwater samples collected from site monitoring wells MW-6 and MW-6D. <br /> J Dissolved TPH-GRO Distribution <br /> A concentration of TPH-GRO was detected above the laboratory MDL in the groundwater <br /> sample collected from site monitoring well MW-1. <br /> Dissolved BTEX Distribution <br /> A concentration of benzene was detected above the laboratory MDL in the groundwater sample <br /> collected from site monitoring well MW-6D. Concentrations of toluene, ethylbenzene and total <br /> r, xylenes were not detected above their respective laboratory MDLs in the groundwater samples <br /> collected from the site monitoring network. <br /> Dissolved MTBE, TBA, DIPE, ETBE, TAME, 1,2-DCA, EDB, Ethanol, and Methanol <br /> Distribution <br /> Concentrations of TBA were detected above the laboratory MDL in the groundwater samples <br /> collected from site monitoring wells MW-1 and MW-6D. A concentration of 1,2-DCA was <br /> detected above the California Primary MCL in the groundwater sample collected from site <br /> monitoring well MW-1. Concentrations of MTBE, DIPE, ETBE, TAME, EDB, ethanol, and <br /> methanol were not detected above the laboratory MDL in the groundwater samples collected <br /> from the site monitoring well network. Concentration maps of the site are presented as Figures <br /> 4 and 5. Concentration versus time graphs for the wells in the site monitoring well network are <br /> presented as Figures 1 through 7 of Attachment G. <br /> `r 5.1.5 Site Conceptual Model Updates <br /> There are no site conceptual model (SCM) updates. Historical analytical soil data, groundwater <br /> gradient and flow direction data, and soil boring and well construction details are presented as <br /> Tables 2, 3 and 4, respectively. Information regarding the collection of soil samples associated <br /> g:\aproject\env\chevron\309075\6 deliverables\periodic monitoring\2012\1sa12\text\309075 I W2 gmrfin 06212012.doe 6 <br /> 1� <br />