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<br />Mr. Robert McClellon
<br />October 23, 2009
<br />Page 3 of 4
<br />sample locations during the quarter ranged from 0% to 19.6%. Carbon dioxide concentrations measured at
<br />all sample locations during the quarter ranged from 0.9% to 26.5%. Results for each probe, each
<br />extraction well, and each passive vent are summarized in Table 1.
<br />Groundwater. An interpreted groundwater contour map was prepared using the data collected on
<br />September 9, 2009 (Figure 2). The groundwater flow direction is to the west at a gradient of 0.00106. For
<br />comparison, the groundwater flow direction varies from the northeast to the southwest (September 29,
<br />2006), from the east to west (June 10, 2008), from the east-southeast to the west-northwest (September
<br />10, 2008), from southeast to the northwest (September 20, 2007), from the southwest to the northeast
<br />(June 29, 2006, December 15, 2006, March 14, 2007, December 9, 2008, and March 11, 2009), from the
<br />west-southwest to the east-northeast (June 14, 2007, December 13, 2007, March 13, 2008 and June 10,
<br />2009).
<br />The following metals were not detected above the analyses reporting limit: aluminum, cadmium, copper,
<br />mercury, selenium and silver. The highest detected concentration of the remaining 11 metals are
<br />0.0218 milligrams per liter (mg/L) for arsenic (MW -1), 0.771 mg/L for barium (MW -2), 0.00317J mg/L
<br />for chromium (MW -3), 0.00660) mg/L for cobalt (MW -1), 0.472 mg/L for iron (MW -2), 0.00466) mg/L
<br />for lead (MW -2), 4.45 mg/L for manganese (MW -2), 0.00777J mg/L for nickel (MW -2), 0.00841J mg/L
<br />for thallium (MW -2), 0.0171 mg/L for vanadium (MW -3) and 0.00619J mg/L for zinc (MW -2). The
<br />highest TDS concentration of 2,330 mg/L was found in MW -2. The field measurements for pH ranged
<br />from 6.72 to 6.75, and specific conductance ranged from 1,910 to 3,520 micromhos (µmhos).
<br />Of the 11 reported metals constituents, primary maximum contaminant levels (MCLS) are established for
<br />6 constituents (arsenic at 0.01 mg/L by EPA and 0.05 mg/L by California Department of Health Services
<br />[DHS], barium at 2 mg/L by EPA and 1 mg/L by DHS, chromium [total] at 0.1 mg/L by EPA and
<br />0.05 mg/L by DHS, lead at 0.015 mg/L by EPA and DHS, nickel at 0.1 mg/L by DHS, and thallium at
<br />0.002 mg/L by EPA and DHS). For the remaining five metal constituents, secondary MCLS are
<br />established for three (iron at 0.3 mg/L by EPA and DHS, manganese at 0.05 mg/L by EPA and DHS and
<br />zinc at 5 mg/L by EPA and DHS). For the two remaining constituents, the California State Action Level
<br />for Drinking Water is established for vanadium at 0.05 mg/L. For the remaining constituent, the
<br />Agricultural Water Quality Limits is established at 0.05 mg/L for cobalt. Secondary MCLs are established
<br />for TDS at 500 mg/L by EPA and DHS and specific conductance at 900 µmhos by EPA. The dissolved
<br />metal results, TDS results, and the field measurements are summarized in Table 2.
<br />The analytical report is provided as Attachment 2.
<br />CONCLUSIONS AND RECOMMENDATIONS
<br />Eleven metals (arsenic, barium, chromium, cobalt, iron, lead, manganese, nickel, thallium, vanadium and
<br />zinc) and TDS were detected above the analytical reporting limits in the groundwater samples collected
<br />on September 9, 2009. Of these constituents, four (iron, manganese, thallium and TDS) were above their
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