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Ms. Kristin Shelton
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<br /> presence of free floating hydrocarbon product; and well VEW 1-D was not sampled because the
<br /> well was actively being used for soil vapor extraction.
<br /> No analytes were detected in the samples collected from wells MW5, MW 11, MW 12, MW 14
<br /> and MW1D. TPHg and benzene were detected in the sample collected from well MW3 at
<br /> concentrations of 74 parts per billion (ppb) and 2.6 ppb, respectively. A low level of xylenes
<br /> was also present in the sample from MW3. TPHg and benzene were detected in the sample from
<br /> ' well MW6R at concentrations of 9,100 ppb and 900 ppb, respectively. Moderate to high levels
<br /> of toluene, ethylbenzene and xylenes were also present. TPHd was detected in the sample from
<br /> ' MW6R at a concentration of 190 ppb. TPHg and benzene were detected in the sample from well
<br /> MW8 at concentrations of 38,000 ppb and 6,600 ppb, respectively. Moderate to high levels of
<br /> toluene, ethylbenzene and xylenes were also present. TPHd was detected in the sample from
<br /> MW8 at a concentration of 4,500 ppb. TPHg and benzene were detected in the sample from well
<br /> MW 13 at concentrations of 290 ppb and 18 ppb, respectively. Low levels of toluene,
<br /> ethylbenzene and xylenes were also present.
<br /> ' MTBE was reported in well MW3 at a concentration of 7.2 ppb, in well MW6R at a
<br /> concentration of 4,800 ppb, in well MW8 at a concentration of 31,000 ppb and in well MW 13 at
<br /> ' a concentration of 11 ppb. No other gasoline oxygenates or additives were detected. Results
<br /> were reported in the Semi-Annual Groundwater Sampling and Remediation Status Report, dated
<br /> July 15, 2015.
<br /> Groundwater analytical results for the first quarter of 2015 are presented in Table 9 and
<br /> cumulative analytical results are summarized in Tables 13 and 14 (Attachment B).
<br /> Isoconcentration maps for TPHg, TPHd, benzene and MTBE are presented on Figures 4, 5, 6 and
<br /> 7, respectively (Attachment A).
<br /> ' Second Quarter 2015
<br /> On June 4, 2015, shallow groundwater was interpreted to flow generally in a southerly to
<br /> ' southwesterly direction, with a mound of high groundwater elevation around well MW8, at a
<br /> gradient ranging from approximately 0.006 ft/ft in the area south of the site to 0.018 ft/ft in the
<br /> central and southern portions of the site. Figure 8 in Attachment A depicts the potentiometric
<br /> surface on June 4, 2015.
<br /> On June 4 and 5, 2015, groundwater samples were collected from wells MW2, MW3, MW4,
<br /> ' MW5, MW6R, MW8, MW10, MW11, MW 12, MW 13, MW 14 and MW1D for analysis. Well
<br /> MW7 was not sampled because the well was dry; well MW9R was not sampled due to the
<br /> presence of free floating hydrocarbon product; and well VEWI-D was not sampled because the
<br /> well was actively being used for soil vapor extraction.
<br /> No analytes were detected in the samples collected from wells MW2, MW4, MW5, MW10,
<br /> ' MW 11, MW 12, MW 14 and MW 1 D. TPHg and benzene were detected in the sample from well
<br /> MW3 at concentrations of 84 ppb and 6.2 ppb, respectively. Low levels of ethylbenzene and
<br /> xylenes were also detected. TPHg and benzene were detected in the sample from well MW6R at
<br /> G:Data\GROUNDZE\WOOLSEY.ROBUdepom\QMR\2015 QMRs\ANNUAL REPORTTiml Textjw.doc
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