WORK PLANS - Laserfiche WebLink

Home Browse Search

All drilling equipment and sampling tools will be cleaned prior to arriving, and before leaving the site. The sample devices will be advanced to the desired sampling depth interval, and a soil drive sampler equipped with acetate liner will be driven into undisturbed soil. The sampler will then be retrieved and dissembled, and the soil filled liners, if retained for chemical analysis, will be sealed with Teflon© paper or foil and plastic end caps, labeled, logged onto chain-of-custody forms and place in a chilled ice chest on crushed ice. The boreholes will be logged using the Unified Soil Classification System under the supervision of a registered geologist using the attached Geoscience protocols Wright has developed for drilling, sealing, temporary well construction, well construction and sampling. Additional lithologic information will be collected to describe the subsurface geology. The samples will be collected at minimum five-foot intervals, at intervals of obvious contamination (field screened by vapor photoionization meter, PID) and at stratigraphic features of interest. Additional soil samples may be collected at intervals closer than 5-feet at the discretion of the logging geologist dependiong upon field conditions encountered. Reconnaissance Groundwater Sampling The groundwater sampling uses a "slip-sleeve" type water sampling device of GeoProbe design. The water sampling device can allow "discrete" water samples to be collected by advancing the device to the aquifer interval of interest, pulling the sleeve back to open a screen for about one-foot length, and then collecting a sample with a bailer lowered through the sleeve. Additional samples deeper in the aquifer can be attempted depending upon the thickness of the aquifer strata, uncased borehole stability, flowing conditions and local aquifer water yield in the specific borehole. At least one groundwater sample will be collected from each borehole and one sample will be collected from the existing water production well. Depth to groundwater measurements will be made to the nearest one-one hundredth of one foot from existing grade. The reconnaissance boreholes will be checked for the presence of separate phase product during the sampling with a bailer (see GeoProbe sampling procedures above). The groundwater sample will be carefully collected with a clean bailer and poured into the appropriate laboratory prepared container with minimum cavitation. Each water sample will be labeled, logged onto a chain-of-custody form, and placed in a chilled ice chest for transportation to a state certified laboratory for analyses as indicated below. Estimate of Groundwater Flow Direction Information relayed to Wright from PHS-EHD indicates that the groundwater flow direction in the immediate site area is north-northwesterly. An estimate of groundwater flow direction will be made from field measurements of depth to groundwater in the uncased boreholes. The depth to water measurements will be made to an arbitrary datum to estimate a flow direction. Groundwater flow contours will be attempted from this data to plot a groundwater flow direction. Please note that groundwater levels may not have sufficient time to completely stabilize so the contoured flow direction will be an estimate only. Borehole Sealing and Drill Cuttings Storage Upon completion of the borehole drilling and collection of information, all boreholes will be backfilled with cement grout,placed from the bottom to top of each borehole. Soil cuttings, decontamination water, cement cleanup water and other debris from this study will be placed in labeled steel 55-gallon drums and stored on-site. The paved surface will be patched with quick setting concrete or asphalt, to match existing. Chemical Analysis Up to six (6) capillary fringe soil samples, six (6) vadose zone soil samples, one (1) aquitard soil sample and seven (7) groundwater samples will be analyzed at a State certified analytical laboratory from the exploratory borings. These samples will be tested for the following: Total Petroleum Hydrocarbons as Gasoline (TPHG), Diesel (TPHD), Benzene(B). Toluene (T), Ethyl-benzene (E) and Xylene (X), Methyl- tert-butyl-ether (MTBE) and fuel Oxygenates, 1,2-Dichloroethane and Ethylene Dibromide using EPA Methods 3510/8015,8020,and 8260. The analyses will be run on a normal turnaround. Page 3