ARCHIVED REPORTS_XR0010562 - Laserfiche WebLink

Home Browse Search

FIELD PROCEDURES . Page 2 Soil borings were sealed to the surface by pumping a slurry of Portland Cement and bentomte into the boring through a tremae pipe Soil generated during drilling activities was placed in sealed, labeled 55- gallon drums and stored on site Monitoring Well Construction Monitoring Well MW i was constructed using four-inch diameter, flush-jointed, Schedule 40 PVC casing, 0 02-inch slotted casing was used for the screened interval Number 3 Monterey sand was placed in the well annulus as a filter pack The filter pack extends from the bottom of the screened interval to approximately two feet above the top of the screened interval A two-foot thick bentonite seal was placed in the well annulus above the filter pack A grout seal consisting of a Portland Cement and bentonite slurry was tremied into the well annulus above the bentonite seal The well was completed with a locking well cap and a flush-mounted, traffic-rated well cover An as-built well diagram is shown on Plate 11 The wells were constructed under the supervision of a California Registered Geologist . Monitoring Well Development, Purging and Sampling After well construction was completed, the water level in each well was measured with an electronic well sounder and the well was checked for free product using a clear bailer The well was subsequently developed using a vented surge block Approximately three well volumes of water were then removed with a suction pump until temperature, pH and conductivity readings stabilized and/or the water cleared of sediment After a minimum of 24 hours from the time of development, the water level in the well was measured, and the water checked for visual signs of free product using a clear bailer Approximately three to five additional well volumes of water were purged using a clean, submersible pump until temperature, pH, and conductivity readings stabilized and/or the water cleared of sediment The water sample was then collected using a new polyethylene disposable bailer Water from the bailer was decanted into appropriate sample containers provided by the laboratory The samples were immediately placed in an ice-chest with "blue ice," along with a travel blank, and submitted under chain-of-custody to a California-certified laboratory for analysis of Total Petroleum Hydrocarbons {TPH) using EPA test method 8015/Purge and Trap, and Benzene, Toluene, Ethylbenzene and Total Xylenes (BTEX)using EPA test method 602/Purge and Trap A travel blank prepared by the laboratory also was analyzed for BTEX, and TPH Pumping equipment was cleaned prior to development/purging of each well with a solution of trisodium phosphate and distilled water to minimize the potential for cross contamination All water removed during development and purging operations was stored in sealed, labeled 55-gallon drums • DDDD°� WAL.LRCS•:(UHL R,c)dedpaps-r &ASSOCIATES INC