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Forward Landfill Water Quality Monitoring Report
<br />Fourth Quarter/Annual 2023
<br />www.arcadis.com
<br />Forward Landfill 4Q23 Water Quality Mon Report_02012024 7
<br />No organic constituents were detected in the the field blanks, or the equipment blank. No VOCs were
<br />measured in the laboratory method blanks analyzed with the groundwater samples. Inorganic constituents
<br />(chloride, dissolved aluminum, dissolved calcium, dissolved copper, dissolved magnesium, dissolved nickel,
<br />dissolved sodium, dissolved potassium, and sulfate) were measured at estimated trace concentrations in one
<br />or more of the laboratory method blanks analyzed with the groundwater samples. Several samples contained
<br />similar reported concentrations of these compounds, which are considered suspected laboratory
<br />contaminants.
<br />Results from the duplicate groundwater sample collected from monitoring well MW-22 are presented in Table
<br />4 along with the primary results for the well. Comparison of the primary and duplicate results for this well
<br />indicates a relative percent difference (RPD) of 20% or less for the routine monitoring parameters (i.e., ORP,
<br />turbidity, temperature, specific conductance, and pH). All results had an RPD of 20% or less, except for
<br />dissolved potassium. Based on evaluation of the laboratory QA/QC data, the laboratory results generated for
<br />the fourth quarter of 2023 were deemed acceptable, and the water quality samples collected from the
<br />Forward Unit are representative of water quality at the Site.
<br />Austin Road Unit
<br /> QA/QC samples at the Austin Road Unit included two trip blanks, six field blanks, one equipment blank,
<br />laboratory method blanks, and one duplicate sample. The method blanks were analyzed for all required
<br />analytes included in the MRP (RWQCB 2014); equipment, field, and trip blanks were analyzed for VOCs by
<br />USEPA Method 8260.
<br />No organic constituents were measured in the trip blanks. PCE was measured in one of the field blanks at a
<br />quantifiable concentration of 0.80 µg/L and chloroform were measured in two of the field blanks at quantifiable
<br />concentrations of 13 µg/L and 4.4 µg/L. Chloroform was also measured in the equipment blank at a
<br />quantifiable concentration of 9.3 µg/L. No VOCs were measured in the laboratory method blanks analyzed
<br />with the groundwater samples. Inorganic constituents (chloride, dissolved aluminum, dissolved antimony,
<br />dissolved barium, dissolved calcium, dissolved chromium, dissolved copper, dissolved cyanide, dissolved
<br />magnesium, dissolved manganese, dissolved potassium, dissolved sodium, dissolved tin, sulfate, , and total
<br />iron) were measured at estimated trace concentrations in one or more of the laboratory method blanks
<br />analyzed with the groundwater samples. Several samples contained similar reported concentrations of these
<br />compounds, which are considered suspected laboratory contaminants.
<br />Results from the duplicate groundwater sample collected from monitoring well AMW-37S are presented in
<br />Table 8a along with the primary results for the well. Comparison of the primary and duplicate results for this
<br />well indicates an RPD of 20% or less for the routine monitoring parameters (i.e., ORP, turbidity, temperature,
<br />specific conductance, and pH). Based on evaluation of the laboratory QA/QC data, the laboratory results
<br />generated for the third quarter of 2023 were deemed acceptable, and the water quality samples collected
<br />from the Austin Road Unit are representative of water quality at the Site.
<br />2.2 Unsaturated Zone Monitoring
<br />This section describes the monitoring conducted within the vadose zone of the Forward Unit during the fourth
<br />quarter of 2023 and the associated monitoring results.
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