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1 <br /> 2. METHODS <br /> Groundwater samples were collected by an OSHA-certified environmental technician on 3 <br /> June 2004 The technician measured water levels and sampled groundwater in all seven <br /> ' monitoring wells at the Penny Newman Grain Elevator site The wells are labeled MW-1 <br /> through MW-7 The wells MW-1 through MW-6 have 20-Foot screen intervals ranging <br /> between 5 and 28 ft bgs, whereas well MW-7 is screened from 30 to 35 ft bgs to assess <br /> groundwater quality in the deeper portion of the aquifer Table 3 provides construction <br /> details for the monitoring wells at this site <br /> 2.1 Sampling Procedure <br /> Depth to water was measured from the top of each monitoring well casing using an <br /> ' electronic water level indicator accurate to 0 01 foot The top of each casing has been <br /> surveyed so we are able to calculate the elevation of the water levels relative to mean sea <br /> level (MSL) After the technician measured static water levels in the wells, each well was <br /> ' purged and then samples were collected for chemical analyses <br /> Wells were purged to remove stagnant water from the casing in order to collect a sample <br /> representative of aquifer conditions Purging involved removing three casing volumes of <br /> water from each well Purging was accomplished utilizing a Grundfos Redi-Flo2 <br /> groundwater pump Measurements of the pH, conductivity, and temperature were collected <br /> and evaluated during purging to ensure that fresh formation water was flowing into the well <br /> Groundwater sampling sheets are presented in Appendix A <br /> A groundwater sample was collected from each well after the water level recovered from <br /> purging to at least 80 percent of pre-purging level Each sample was collected using a new <br /> disposable polyethylene bailer Samples were transferred from the bailer to laboratory- <br /> provided sample containers with a slow-emptying device to minimize turbulence and volatile <br /> losses Sample containers were labeled with the location, date, time, sampler name, <br /> analyses to be performed, and preservatives that had been added to the sample containers <br /> After labeling, the samples were placed in a cooler chilled to at least 37'F for delivery to a <br /> California-certified laboratory under a standard chain-of-custody procedure All <br /> groundwater samples were analyzed by EPA method 8260B for BTEX and 8015M for TPHd <br /> ' and TPHg <br /> 2.2 Quahty Control/Quality Assurance <br /> We utilize a blind duplicate and trip blanks as part of the quality assurance program for this <br /> project A duplicate groundwater sample is collected from one monitoring well at the site <br /> The sample is labeled with the same information as the other groundwater samples, but is <br /> given a fictitious name The true identity of the sample is not disclosed to the laboratory <br /> This quarter, a duplicate sample was collected from MW-4 and was labeled "MW-8" on the <br /> 1 chain-of custody form Trip blanks were also prepared and labeled by the analytical <br /> laboratory and transported to the site along with the empty groundwater sampling <br /> containers The trip blanks remain unopened and are transported back to the laboratory with <br /> the other groundwater samples, one trip blank is submitted to the Iaboratory for each sample <br /> cooler delivered to the laboratory The laboratory adheres to its own quality control and <br /> HALEY& <br /> ' ALDRICH 4 <br />