FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

• • • 0 Geosyntec'-' consultants Anions, including chloride and sulfate were detected in all groundwater samples at concentrations ranging from 53 mg/L to 360 mg/L for chloride and 120 mg/L to 440 mg/L for sulfate. Nitrate as N was reported in groundwater samples collected from GSB-1 and GSB-2 at concentrations of 0.33 mg/L and 51 mg/L, respectively. One groundwater sample collected from GSB-2 exceeded the MCL of 10 mg/L for nitrate as N (Cal EPA, 2008). Chloride and sulfate concentrations in groundwater samples collected from GSB-2 and GSB-3 exceeded the SMCL of 250 mg/L for both chloride and sulfate (Cal EPA, 2006). Reported alkalinity and bicarbonate alkalinity concentrations in groundwater ranged from 400 mg/L in GSB-1 to 990 mg/L in GSB-3. Reported TDS concentrations ranged from 650 mg/L in GSB-1 to 2,000 mg/L in GSB-2 and exceeded the SMCL of 500 mg/L (Cal EPA, 2006). Alkalinity and bicarbonate alkalinity do not have MCLs, SMCLs,water quality goals, or health advisory levels. Ammonia was reported at concentrations ranging from 0.56 mg/L in GSB-2 to 6.2 mg/L in GSB-3. The USEPA has established a health advisory level of 30 mg/L for ammonia (USEPA, 2012). All reported ammonia concentrations were below the health advisory level. 4.4 Quality Assurance and Data Validation Quality assurance/quality control (QA/QC) measures were implemented in the field to ensure that proper sample collection and handling procedures were used. These measures included collection and analysis of a blind duplicate groundwater sample from GSB-3 and an equipment rinsate blank collected in the field (for non-dedicated sampling equipment). Low levels of barium and sodium were reported in the equipment blank; however, primary sample concentrations were greater than ten times the reported equipment blank concentrations and therefore did not require qualification. The calculated relative percent differences for the primary and blind duplicate groundwater samples were found to be acceptable, demonstrating appropriate precision during field collection and laboratory testing procedures. The duplicate sample results are included in Table 1. The laboratory reported all requested analyses, the data reports were complete, and all quality assurance data met the acceptance criteria for the samples collected. The results of the data QA/QC and validation activities performed are summarized in Data Quality Phase II ESA_1351 Dupont_FINAL_12302013 8 1/2/14