ARCHIVED REPORTS_XR0012711 - Laserfiche WebLink

Home Browse Search

�. . E V Quik Stop Market No. 132 August 14, 1990 Job No. 349132-31 Page 3 r- hollow-stem auger. The screened interval of the casing will extend sufficiently above the water table so that the presence of free floating product can investigated. As the auger is withdrawn, sand will be slowly poured down the borehole annulus to approximately 2 feet above the slotted screen section. Bentonite pellets will be placed on top of the sand and hydrated to form an annular seal. The remaining portion of the annular space will be sealed with a neat cement and bentonite grout. The top of the well will be set in a waterproof traffic-rated vault box slightly above grade with a locking cover to provide security and protect the PVC wellhead. A concrete surface seal will be installed to complete the well construction. Well Development After construction, the well will be developed using a surge block to agitate and set the } sand pack around the annulus of the well casing. A bailer will be used to remove water manually after each surge. Well development (a) removes residual silts and clays left from the drilling and (b) improves the hydraulic conductivity between the wells and the natural formation. After development, the well will be allowed to recharge with water from the surrounding formation (approximately 72 hours), enabling Exceltech to collect a representative water sample and to measure the thickness of any floating f product encountered. All water collected during well development will be placed in DOT 17E drums and left (7. on-site until laboratory analyses are complete. At that time, the d.ums and water may be properly disposed of by the client. Groundwater Sampling Before sampling groundwater, an Exceltech geologist will field-check the monitoring wells with an interface probe or a clear acrylic bailer to check for the presence of free- floating product: In monitoring wells where no floating product is observed, each well will be purged of a minimum of 4 well casing volumes of groundwater before sampling. Purged water will be placed in DOT 17E drums. All important well s sampling information will be included in the final report. The information will include u pH, temperature, conductivity,and water volume removed. a Samples will then be collected with a clean Teflon bailer and transferred to - appropriate laboratory-supplied bottles. The samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHG); benzene, toluene, ethyl benzene, and xylenes @TE7C�; total lead; and organic lead. Each bottle will be labeled and logged on _ a chain-of-custody._.form and placed in a cooler containing ice for transport to a California-certified.laboratory. Appendix A includes the Exceltech Groundwater------- Sampling Protocols.. k i `