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Evaluation ofNatural Attenuation_7500 West Eleventh Street, Tracy, Cry. Page 53 • MWFP-1 though MWFP-5 to monitor conditions in and around the 3 area of relatively-elevated concentrations of components of fuel . hydrocarbons that is centered around Monitoring Wells MWFP-1 and MW-7; and 1 • MW-12, located in the secondary plume of affected groundwater that == is present at the site. The scope of groundwater-quality monitoring described above is greatly in excess of the scopes recommended by either the ASTM guidance or the results of the MAROS analysis. It is not intended as a final monitoring program design but as a conservative interim step that will permit additional data to be gathered that can be expected to add confidence to a later decision to adopt a ground-water quality monitoring program for the site that incorporates all of the MAROS recommendations. -,: The revised monitoring program will be initiated at the time of the June 2005 groundwater sampling round and ran through the March 2006 monitoring round. 10.2.2 March 2006 MAROS Analysis Following the planned March 2006 monitoring round, a complete MAROS analysis will again be performed using all of the quarterly geochemical data gathered from the site r through that time. ` 10.2.3 Optimal Scope and Frequency of Long Terra Monitoring If, as is expected, the second MAROS analysis produces recommendations that the frequency of recovery of groundwater samples from the majority, if not all, wells should be reduced to once per year or once every two years, a revised groundwater-quality rin monitoprogram should be adopted that complies with the results of that analysis. monitoring � P p Y To obtain measurements of the concentrations of analytes of concern in groundwater when they are likely to be the highest that occur over the annual cycle of rise and fall in the elevation of the groundwater table, annual and/or biennial monitoring rounds should be conducted in July. 10.2.4 Suite of Analytes to be Monitored The next round of groundwater-quality monitoring at the site is planned for June 2005. Because the results of the analyses of the groundwater samples recovered during the March 2005 sampling round again demonstrated that there are no lead scavengers or �f alcohol gasoline additives in the groundwater, the samples recovered in June 2005 will be analyzed for the following suite of analytes: sic