ARCHIVED REPORTS_SECOND QUARTER GROUNDWATER MONITORING REPORT MAY 2010

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' Second Quarter Groundwater Monitoring Report—May 2010 Sutter Home Winery ' Page 7 Table 5: Wastewater Pond' Standard Minerals Monitoring Results—Second Quarter 2010 ' WDR R5-2009-0073 Alkatini Date Boron Ca Iron Mg Mn K Sulfate Total H droxide Carbonate Bicarbonate Hardness 5/6/10 0.43 41 0.62 12 0.17 630 8.3 1000 <1 <1 1000 150 Samples collected from Pond 2. All results reported in milligrams per liter(mg/L) Ca=calcium Mg=magnesium Mn=manganese K=potassium ' SUMMARY/DISCUSSION OF RESULTS ' Provision F.1 of WDR Order No. R5-2009-0073 states that wastewater discharge, in combination with other sources, shall not cause underlying groundwater to contain waste constituents in concentrations statistically greater than background water quality. Groundwater quality is highly variable across the Site. In general, many of the highest salinity-indicators (TDS, FDS, EC, sodium, and chloride) and nitrate values occur in areas where no or limited land application of wastewater has occurred. The Site is preparing a Background Groundwater Quality Standard Report which is due July 1, 2013, to determine the Site's background ' groundwater quality and verify the Antidegradation Study previously submitted. Effective July 1, 2014, final groundwater limits will be the numeric groundwater quality objectives or background groundwater quality as determined by the background evaluation,whichever is greater. ' Prior to completion of the Background Groundwater Quality Standard Report, interim background concentrations of groundwater constituents are established as the highest concentration from the second through ninth monitoring events (eight monitoring events total) conducted for each of these wells. The first sampling event following installation of the monitoring wells was not used to decrease the potential of well construction materials having influenced the groundwater quality (principally salinity)proximal to the wells. Groundwater data from two hydrologic cycles early in the land application history are expected to be the ' most consistent with background constituent concentrations prior to wastewater application and to account for seasonal fluctuations in groundwater levels and constituent concentrations. The limited sample dataset precludes a more rigorous statistical treatment. ' In general, review of laboratory analytical results indicates that current concentrations are consistent with historic values (Historic Groundwater Monitoring Data, Appendix B). The groundwater samples collected ' from GW-3 and GW-7 in May 2010 exceeded their intra-well background concentrations of 18 milligrams per liter (mg/L) and 14 mg/L, respectively, for Nitrate-N. The groundwater sample collected from GW-6 exceeded its intra-well background concentration of 1,280 micro-mhos per centimeter(µmhos/cm)for EC. ' Salinity indicators TDS and EC exceeded the California Secondary Maximum Contaminant Levels (MCLS) for drinking water of 500 mg/L and 900 µmhos/cm, respectively, in monitoring wells GW-2, GW-5, GW-6, GW-8, GW-10, GW-11, GW-13, GW-14, GW-15, and GW-18. The samples collected from GW-1, GW-7, ' GW-9, GW-16, and GW-17 exceeded the secondary MCL for TDS but not for EC.Nitrate-N concentrations exceeded the primary MCL of 10 mg/L in monitoring wells GW-3, GW-5, and GW-7 through GW-15. ' Fixed dissolved solids are the portion of total dissolved solids generally not subject to biologic treatment by soil microorganisms. Concentrations of FDS in monitoring wells GW-5, GW-6, GW-8, GW-14, and GW-15 exceed the agricultural water quality screening level of 450 mg/L for TDS; however, none of the wells ' exceed their intra-well background concentration for FDS. In general, FDS concentrations observed in monitoring wells GW-1 through GW-7 are trending flat or downward since inception of monitoring in 2002 (Figure 7,Appendix A). ' 4M 116,10 CONDOR