SITE INFORMATION AND CORRESPONDENCE FILE 2

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Cambridge Drive (CVRWQCB case #391002 and Geotracker ID# T0607700822). They started injecting ozone August 2010 and then manganese (Mn) started showing up in gw samples from September 2010. They shutdown the ozone on June 15, 2011 when Mn actually increasing in most wells, as in NOT attenuating. There were three Mn sampling events for some wells, two sampling events for other wells. They were September 28, 2010, March 23, 2011 and Sept 22, 2011 . MW-1 , 2, 3, & 4 had only two events. The other wells had all three events . Except for MW-3 and MW-4, the other wells all went up in concentrations. For example, September 2010 data showed Mn in MW-1 at 1800 ug/I. Then in March 2011 it was up to 13,000 ug/I. MW-2 up from 820 to 4600 ug/I for the same events. MW-7 was the biggest hit. Sept 2010 Mn was at 2700 ug/I. Then up to 14,000 on March 2011 and then to 17,000 on Sept 22, 2011 . There has not been another gw sampling event for Mn since Sept 22, 2011 . Ben Chevlen plans on sampling next for Mn during First Quarter, 2012. 1 questioned if his contingency plan had a plan for what to do if the rise in Mn continues? Short of just turning off the ozone (they did, June 2011), he didn't know of another plan. Plus he won't know until after the First quarter data is in if Mn is a significant concern. Jim, do you think waiting til Jan or Feb 2012 is good enough for what little hx we're seeing at this site for Mn? I recommended he check with you and his boss, Shelby Lathrop to see if a Fourth Quarter Mn sampling event could be done on the wells still at high Mn levels. What do you think? As if this wasn't enough, they're thinking NFA..... 3