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TABLE 8 ANALYSIS OF CHROMIUM CONCENTRATIONS AND REDUCTION POTENTIAL FORMER MARLEY COOLING TOWER SITE STOCKTON,CALIFORNIA Page 3 of 3 Percent Change in Most Recent Concentration Description of Trend for Key Indicator Parameters Potential for Monitoring Concentration(µ Concentrations fromg/L) has been Further Maximum Oxidation Reduction Recommendation` Well Total Chromium Total Chromium Below 50µg/L Chromium Iron Manganese Total Organic Carbon Chromium Potential Chromium VI Chromium VI Since' Reduction Background and Compliance Wells 1/2009(Before Reverted to MRP Section I Groundwater MW-7 9J 4.96 -83% -75% 2008) Stable below WQO Near baseline Near baseline Low Positive Low Monitorign Requirements MW-201 14 8.48 -78% -21% 1/2009(Before Stable below WQO Near baseline Near baseline Low Positive Low Continue performance monitoring per the MRP 2008) MW-202 4J 4.41 -88% -1% Before 2008 Stable below WQO baseline Near WQO and Baseline(ND) Low Positive Low Reverted to MRP Section I Groundwater Monitorign Requirements MW-210 <10 0.93 -76% -29% Before 2008 Stable below WQO baseline Below WQO,Near Below WQO Low Positive Low Reverted to MRP Section I Groundwater Monitorign Requirements MW-302 <10 1.02 -100% -52% Before 2008 Stable below WQO baseline Below WQO,Near Baseline(ND) Low Positive Low Reverted to MRP Section I Groundwater Monitorign Requirements MW-304 11 8.32 -69% -17% Before 2008 Stable below WQO Abovebaselineand Baseline(ND) Low Positive Low Continue performance monitoring per the MRP MW-401 <10 1.22 -100% 0% Before 2008 Stable below WQO Below WQO Baseline(ND) Low Positive Low Reverted to MRP Section I Groundwater Monitorign Requirements MW-310 91 7.82 -80% -6% Before 2008 Stable below WQO Above baseline,above Baseline(ND) Low Positive Low Continue performance monitoring per the MRP but near WQO MW-211 3J 2.06 -82% -1% Before 2008 Stable below WQO Below WQO Baseline(ND) Low Positive Low Reverted to MRP Section I Groundwater Monitorign Requirements MW-325 8J 5.57 -74% -29% Before 2008 Stable below WQO Above baseline,below Baseline(ND) Low Positive Low Continue performance monitoring per the MRP WQO Notes: a =Dates in parentheses represent chromium VI,if the date is different than for total chromium. n =Potential for further chromium reduction is based on the presence of iron,manganese,total organic carbon,and depressed oxidation reduction potential readings,as discussed by chemical in Section 4.0. =Recommendation is based on analytical concentrations and when the last injection occured. a =Well will continue to be routinely sampled for chromium and other parameters as specified for the sitewide groundwater monitoring program in the MRP. Bold=Concentration greater than the WQO gg/L=microgram per liter J=Estimated laboratory value MRP=Monitoring and Reporting Program No.R5-2012-0814 issued by the California Regional Water Quality Control Board,Central Valley Region,September 5,2012. NS=not sampled ND=not detected NM=not meaningful because the chemical has not been detected above the laboratory analytical reporting limit. WQO=water quality objective