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LEEDSHILL•HERKENHOFF, INC. <br /> A bentonite seal was placed above the sand pack and the remaining annular <br /> space was filled with a cement-grout mixture. Finally, a cap and locking <br /> metal surface casing and a Christy box was installed to protect the well . <br /> The well construction details are shown on Figure 3.5. <br /> ' All wells were developed by repeated cycles of pumping or bailing the well <br /> dry and allowing it to recover. Monitoring wells #1, #2, and #3 were devel - <br /> oped using an stainless steel bailer. Monitoring wells #1 and #3 recovered <br /> quickly after bailing allowing in excess of 100 gallons to be removed from <br /> ' each well . Monitoring well #2 did not produce as well as the other wells, <br /> therefore it was developed to a point of being able to sample, after 30 <br /> gallons were removed. Monitoring well #4 had sufficient head and production <br /> .' such that a Grundfos stainless steel submersible pump could be used for <br /> development. Several hundred gallons were removed during development. <br /> After development, representative groundwater samples were collect. Prior <br /> to sampling, an additional one to two well bore volumes were removed from <br /> ' each well using a three-inch Teflon hand bailer. While the wells were being <br /> purged, field measurements of electrical conductivity, temperature, pH, and <br /> depth to water were monitored to ensure the collection of stable, represen- <br /> tative groundwater samples. The water samples were collected in sterile <br /> sampling bottles, appropriately labeled and cooled until they reached APPL <br /> laboratory. The samples were tested for purgeable halocarbons (EPA Method <br /> ' No. 601) . A confirmation sample was also collected in July 1988, from <br /> monitoring well #4. <br /> ' An identical Health and Safety program and Quality Control/Quality Assurance <br /> program as used in the source identification field work, was enacted in the <br /> groundwater investigation field work. An additional quality control measure <br /> was undertaken by collecting a confirmation sample from monitoring well #4. <br /> ' The depth to water in the four monitoring wells and three municipal wells <br /> were measured to determine the groundwater gradient and direction of flow. <br /> The measurements were first taken on June 2 and 3, 1988, after the monitor- <br /> ing wells had recovered at least twelve hours after development. Subsequent <br /> confirmation measurements were taken on June 22, and July 25, 1988. This <br /> ' data is presented on Table 3.1. <br /> ' 3-9 <br />