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Erriie's General Store - 4 - 22 November 2011 <br /> 4407' E. Waterloo Rd., StodOn <br /> San Joaquin County <br /> Goals as 2032, based on the line starting with the peak concentration in 2005, extended along <br /> the slope of the 2004-2010 data linear trend line (Graph 2). <br /> Public Participation <br /> Public participation was conducted from 1 April 2011 to 31 April 2011 with no comments <br /> received by this agency. <br /> Summary and Recommendations <br /> The Ernie's General Store has complied with all of the requirements in Regional Board staff <br /> letters. Peak concentrations of petroleum hydrocarbons in groundwater decreased <br /> approximately 66% between 2005 and 2010, and monitoring shows contamination will <br /> continue to decline without active remediation. The petroleum hydrocarbons plume is <br /> estimated to reach and remain below water quality goals (WQGs) by 2032. Additional soil or <br /> groundwater remediation are not cost effective or necessary, as residual soil and groundwater <br /> contamination poses minimal risk to sensitive receptors, human health, or other beneficial <br /> uses of groundwater in the area. Site use (commercial as a service station and convenient <br /> mart) is not expected to change in the foreseeable future. Based on the minimal residual <br /> contamination in groundwater, lack of threats from vapor intrusion or residual soil <br /> contamination, a stable plume with slowly declining groundwater concentrations, compliance <br /> with the tasks of Regional Board directives, and a well-defined vertical and lateral extent of <br /> pollution, no further action is warranted for the Site. Staff recommends closure of this Site. <br /> The required public participation comment period was conducted with no adverse comments. <br /> The monitoring and remediation wells were properly abandoned on 20 September 2011. The <br /> RP and San Joaquin County Environmental Health Department concur with closure. <br /> Attachments: Figure 1: Site Location <br /> Figure 2: Site Plan with borings, grab groundwater sample locations, and wells <br /> Figure 9: Estimated Lateral Extent of Absorbed TPHg <br /> Figure 10: Estimated Extent of Dissolved MTBE <br /> Table 2: Historic Soil Analytical Data <br /> Table 3: Groundwater monitoring results 2003-2010 <br /> Graph 1: Groundwater Concentrations and Water Levels versus Time <br /> Graph 2: Time to Reach Water Quality Goals <br />