ARCHIVED REPORTS_XR0010388 - Laserfiche WebLink

Home Browse Search

1 Table 1-1 2004 Sampling Schedule San Joaquin County Human Services Agency Quarter Monitoring Wells to be Sampled First MW-2,MW-2A and MW-9 ' Second MW-2,MW-2A,MW-3A,MW-4,MW-6,MW-7 and MW-9 Thtrd MW-2,MW-2A and MW-9 Fourth MW-2,MW-2A,MW-3A,MW-4,MW-5,MW-6,MW-7,and MW-9 2.0 FIELD SAMPLING SUMMARY ' Groundwater samples were collected from monitoring wells MW-2,MW-2A,MW-3A,MW4,MW-5,MW- 6,MW-7,and MW-9 (Figure 1-1) on December 16 and 17,2004 Groundwater sampling field data sheets for the monitoring wells are presented in Appendix B In addition, an equipment blank water sample and a sample from the on-site monitoring well purge water holding tank were collected and submitted for analysis ' Prior to well purging, water levels were measured in all wells on December 16 and 17,2004 to collect data for potentiometric contouring The standing water volumes within wells scheduled for sampling were calculated using water levels measured in each well at the time of sampling and total well depths A submersible pump attached to a dedicated discharge hose was then lowered into the well and used to purge three well casing volumes from each of the monitoring wells ' At the beginning and during the purge process,the temperature,pH,specific conductance,dissolved oxygen, and turbidity of the purge water were measured and recorded on a sampling data sheet The pump was then ' removed and a disposable bailer was lowered into the well for the collection of groundwater samples for benzene,toluene,ethylbenzene,and total xylene(BTEX),and for total petroleum hydrocarbons as gasoline (TPH-g)analysis The groundwater sample was transferred from the disposable bailer into 40-milliliter(mL) glass sample containers Sample containers containing air bubbles were discarded and recollected Samples ' were then 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 with non-phosphate detergent and washing the outside of the pump Dedicated purge tubing was used for each well ' Purge water from monitoring wells MW-2 and MW-2A was stored in 55-gallon drums in the San Joaquin County garage located at 130 North Hunter Street and meets the requirements for transfer and disposal at a ' licensed treatment facility All drums at this location were removed on December 23, 2004 prior to demolition of the former San Joaquin County garage A new location for drum storage is pending ' The groundwater samples were analyzed by United States Environmental Protection Agency(EPA)Method 8015B/8021B for BTEX and TPH-g Groundwater sample analyses were performed by Sequoia Analytical Laboratory in Sacramento, California Additionally, WESTON collected a sample of water stored in the holding tank staged at the loading dock of the San Joaquin Human Services Agency building at 145 South