ARCHIVED REPORTS_XR0010378 - Laserfiche WebLink

Home Browse Search

3 YMNGERS CESCEa5 C0611LiNR5 ' 2.0 FIELD SAMPLING SUMMARY • ' Groundwater samples were collected from monitor wells MW-2A, MW-7, and MW-9 (Figure 1-1) on 19 September 1997 Only wells MW-2A and MW-9 were scheduled for sampling, however, MW-7 was also sampled to provide additional data for the CAP. Groundwater ' sampling data sheets are presented in Appendix B. ' Prior to sampling water levels in all wells were measured on 18 September. The standing water volumes within wells scheduled for sampling were then calculated using the water level ' measurements and total well depths A submersible pump was used to purge three well casing volumes from monitor wells MW-2A and MW-9. A micropurge method was used for well MW- 7 With the micropurge method groundwater is pumped at less than 1 liter per minute from the ' screened interval until groundwater parameters stabilize. ' At the beginning and during the purge process, the temperature, pH, specific conductance, dissolved oxygen, oxydation/reduction potential, salinity, total dissolved solids of the purge ' water were measured This information was recorded on a sampling data sheet Groundwater samples for benzene, toluene, ethylbenzene, and xylene (BTEX) and purgable petroleum hydrocarbons as gasoline (TPH-G) analysis were collected from wells MW-2A and MW-9 with '• a disposable bailer and nylon string Groundwater samples collected from wells MW-2A, MW-7 and MW-9 for methane, iron, nitrate, and sulfate were collected directly from the pump The groundwater sample was transferred into 40 ml glass sample containers. Sample containers were checked for air bubbles The sample containers were sealed in a plastic bag, placed with ice in ' an insulated chest, and logged on a chain-of-custody form for delivery to the analytical laboratory The pump used to purge and sample the wells was thoroughly cleaned prior to each use by placing it into a container of tap water, washing the outside, and pumping water and Alconox ' through the pump and attached hose Tap water was then pumped through the pump and hose ' Purge water from monitor wells MW-7 and MW-9 was stored in a holding tank located at 222 E Weber Avenue The purge water stored in the holding tank was sampled and discharged to the sanitary sewer on 1 October 1997 under a permit from the City of Stockton Department of ' Municipal Utilities Purge water from MW-2A was stored in a 55 gallon drum located at 100 N Hunter Street MW-2A purge water will be disposed of at a licensed treatment facility collected from wells MW-2A and MW-9 were analyzed b • All groundwater samples c Y Y EPA ' Method 8020 for BTEX and by EPA Method 8015M for TPH-G Groundwater samples L�PROIECMSANJOQ5HSA\HSq 47S£P 4 Nawmber IW7