ARCHIVED REPORTS_XR0006498 - Laserfiche WebLink

Home Browse Search

CLEARWATER G R O U P, I N C // Environmental Services f� Clearwater responded to the County's request with a letter workplan dated June 1, 1998 proposing the collection of a final round of samples, including the requested additional analytes This letter report serves to evaluate and present the results of this final round of groundwater;sampling Objective of Additional Assessment As requested by the County, additional groundwater sampling activities included the following • Collection of groundwater samples using well purging methods from eight(8)wells • Laboratory analysis of groundwater samples for total petroleum hydrocarbons as gasoline (TPH-G) by EPAM 8015M, and benzene, toluene, ethylbenzene, xylenes (BTEX) and methyl tert butyl ether (MTBE) by EPAM 8020 • Additional requested analysis for fuel additives by EPAM 8260 for tert-butanol, MTBE, diisopropyl ether,ethyl-tert-butyl ether, tert-Amylmethyl ether Groundwater Monitoring Field Activities On December 10, 1998, all eight monitoring wells (MW-1 through MW-8) were gauged and sampled These wells are shown on the attached site plan (Figure 2) An electronic water level indicator, accurate to within ±0 01-foot, was used to gauge depth to water All wells were checked for the presence of SPH prior to purging No measurable thicknesses of SPH were observed on groundwater in any`of the wells The wells were purged of groundwater according to CRWQCB and County guidelines Each well was purged of three well casing volumes, at which point sampling parameters (temperature, pH, and conductivity) had stabilized Field activities were performed in accordance with Clearwater's Field Procedures (Appendix A) Groundwater monitoring and well purging information are presented on Gauge Data/Purge Calculations and Purge Data sheets (Appendix B) Following recovery of water levels to at least 90% of their static levels, groundwater samples were I collected from the wells using dedicated polyethylene bailers and transferred to laboratory supplied containers' Sample containers were labeled, documented on a chain-of-custody form, and placed on ice in a cooler For 'transport to the project laboratory Groundwater samples were analyzed for' concentrations of TPHg, BTl and;'MTBE using EPA Method's 8015/8020 (modified) and for five selected fuel additives by EPAM 8260 The laboratory samples were analyzed by Entech Analytical Labs, Inc (Entech), a DHS-certified laboratory located in Sunnyvale, California age,31