SITE INFORMATION AND CORRESPONDENCE FILE 1

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11/08/1996 08:57 120983-52 WRIGHT ENVIKUNt AL rHuc off Classification System under the supervision of a registered geologist using the Wright Sampling Geoscience Probbcols(see Attachment B). The samples will be collected at a minimum of five foot intervals. at intervals of obvious contamination and at stratigraphic features of hvietest. Additional lithologic information will be collected to describe the subsurface ;boiogy at the discretion of the supervising geologist. Selected samples may be field wswd using the Hanby' Field Colorimetric Test, a semi- quantitative field laboratoty test for presence of hydrocarbons. 'These tests provide rapid reconnaissance data:oft estimated hydrocarbon concentrations present in soil a groundwater. The ultimift boring depths are estimated to be 15 to 25 feet. When soil samples arc rifted for laboratory chemical analysis the sampler will be equipped with clean smite-steel or brass liner will be sealed with Teflon'"paper and plastic endcaps. All smokes will be immediately labeled, logged onto chain-of-custody forms and placed in a ehffled ice chest for delivery to a state-certified laboratory for analysis, Task 1.2 - Monitoa'iag'M►rill Construction: Monitoring wells will be*mstructed using precleaned, threaded 2-ineb diameter schedule 40 PVC well caadttg, screening the entire thickness of the aquifer, and a portion above the eaplllar�fringe to allow observation for possible floating product. Final well design and phoement will depend upon subsurface conditions encountered. The annulus between diecasing and the borehole will be backfilled with 2112 sand to about two feet above the gens. A bentonite clay spacer about two feet thick will be placed above the sand petit;and torment grout will be pumped from above the bentonite to the surface using a U*Oe pipe. A traffic rated access vault box with locking device will cap the well. The wells will be developed to removed the drilling muck, grade the sand pack and provide a there complete hydraulic connection to the aquifer. The well volume will be calculatedvid a number of those volumes well be removed until the water becomes clear and braes amount of sand pumped is minimal. The well will be allowed to recover prior to sampling. A log of the development will be kept for the well. Newly constructed%yells will be surveyed to a known reference. Task 1.3 - Well Satter: Groundwater samples wl#!'bes collected from existing and newly constructed wells on a quarterly basis. Each monitoring well will be purged using calculated well volumes based on the depth m wa*r in each casing. As each purge volume is removed, measureatents of pH, temperature, and conductivity will be taken until these parameters stabilize, which is inserprtiod to be aquifer water entering the casing. Field testing of physical and biologic peam:mrs will be conducted and or collected immediately (i.e., dissolved oxygen, oxidad i-tedtwtion potential, pH, conductivity, temperature, alkalinity). Samples eolk**d for chemical analysis will be carefully collected with a C'ox&Cox A^tPr pmject No. 4090 DJUFT Page 3