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' Severn Trent Laboratories (STL) of Pleasanton California analyzed the soil samples <br />' STL is a California Department of Health Services (DHS) certified laboratory <br /> 4.1.1 Soil Sampling and Drilling Equipment Decontamination <br /> Prior to and between soil bonngs for monitoring well installation, all down-hole soil <br />' sampling equipment was thoroughly cleaned using a dilute solution of phosphate-free <br /> detergent then rinsed with potable water <br />' 4.1.2 Disposal of Soil Cuttings and Drilling Fluids <br />' Soil cuttings and decontamination water were collected in Department of Transportation <br /> (DOT)-approved 55-gallon drums and have been stored onsite pending review of <br />' analytical data and approval for disposal <br /> 4.2 MONITORING WELL INSTALLATION <br />' Monitoring well construction, development, and sampling procedures are discussed in <br />' detail in the following sections <br /> 4.2.1 Monitoring Well Installation Procedures <br />' A total of four monitoringwells (MW-1 through MW-4) was installed at the site in the <br /> g <br />' locations previously reviewed and approved by SJCEHD The monitoring wells were <br /> constructed of 2-inch diameter Schedule 40 polyvinyl chloride (PVC) well casing and <br /> machine slotted screen Because it was anticipated that groundwater is likely to occur <br /> under semi-confined conditions, the screened interval for the wells consists of 20-feet of <br /> machine slotted 0 010-inch screen to allow for a portion of the well's effective interval to <br />' extend above the potentiometric surface This was done in order to allow for monitoring <br /> for the potential presence of free-phase petroleum hydrocarbons <br />' During installation, the well casings remained suspended while the filter pack was being <br /> placed The augers were withdrawn from the borehole incrementally during placement of <br />' the filter pack material Filter pack depths were monitored frequently during placement <br /> Due to the limitations of the limited access drill ng used for the installation of MW-4, <br /> surging of the well during filter pack installation could not be accomplished The SJCEHD <br />' approved the use of a small amount of potable water added to the borehole annulus to <br /> • facilitate efficient placement of the filter pack In wells MW-1 through MW-3, the wells <br />' were surged during filter pack placement in order to facilitate placement of the filter pack <br />' 5 V\Goodwin ProctorTinaiReport doc <br />