Laserfiche WebLink
three irrigation wells located down gradient of the site. The closest irrigation well <br /> should be investigated and times and periods of this operation should be determined. <br /> EHD will require the closest irrigation well, located at Lathrop Grammar School 1584 <br /> feet northeast of the site, to be sampled and analyzed for the same petroleum <br /> constituents being analyzed for in samples from the monitoring wells on site. <br /> You are hereby directed to contact the owner of the well and gain access for sampling <br /> the groundwater from it. The sample should be collected at the end of the period the <br /> well has been operating to ensure that any pumping influence this well may have on <br /> the shallow groundwater will be represented. If this well is impacted with petroleum <br /> constituents, you are to take actions to also obtain access to the next, further out, <br /> irrigation well, and have the sample from it analyzed for petroleum. <br /> The extent of the influence from these large pumping wells should be evaluated with <br /> respect to the offsite migration of the petroleum plume as soon as possible. <br /> Developing effective corrective actions for the site depend on a through <br /> understanding of the influence effecting plume migration. If the petroleum plume has <br /> migrated to these irrigation wells, you are to immediately evaluate an interim remedial <br /> action that will effectively control the offsite migration. The interim plan should be <br /> submitted to EHD as soon as the need is determined and the action evaluated. <br /> ConocoPhillips consultant is currently investigating the irrigation wells at Lathrop Grammar <br /> School and will determine pumping rates, times of operation, and the influence these wells <br /> may have on the hydrocarbon plume at 16470 Cambridge Street. Additionally, <br /> ConocoPhillips has made initial contact with the Lathrop Grammar School and will collect a <br /> groundwater sample from the nearest irrigation well and analyze for the same constituents <br /> that site groundwater monitoring wells are analyzed for upon receipt of an access agreement. <br /> On March 7, 2002, EHD approved the work plan to install MW-10 thru MW-15. <br /> Conditions of the approval included a requirement to analyze "a representative <br /> groundwater sample for Total Lead by EPA 6010 and Methanol by EPA 8015m." The <br /> report of the monitoring well installation and groundwater data did not include this <br /> required data. <br /> You are hereby directed to additionally sample and analyze a groundwater sample <br /> from each monitoring well associated with this site for Total Lead by EPA "LUFT" <br /> method and Methanol by EPA 8015m at the next quarterly monitoring and sampling <br /> event. <br /> The lack of analysis for Total lead and Methanol during the last investigation was an <br /> oversight by our consultant. ConocoPhillips has instructed our groundwater sampling <br /> contractor to analyze all groundwater samples from the next sampling event for Total Lead <br /> and Methanol. If Total Lead or Methanol is not detected, ConocoPhillips requests that these <br /> analyses be discontinued. <br /> When the lateral and vertical extents of the petroleum constituents associated with <br /> this site have been defined, you should present the report of findings to EHD in the <br /> context of a site conceptual model. Conclusions for delineation of petroleum in the <br />