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{ 1 A S S O C I A T E S I N C 2�3 Groundwater Monitorin2 Well Construction ' Soil borings MW2, MW3, and MW4 were subsequently completed as a groundwater monitoring wells to evaluate the extent of impacted groundwater beneath the site The wells were constructed with 2-inch PVC casing The screened interval of the wells were positioned from ' approximately 5 feet above to 15 feet below the encountered water table to allow for seasonal water level fluctuations, or approximately 45 to 65 feet bgs The screen slot size is 0 010-inch Well construction details are depicted on the well logs contained in Appendix A 2.4 Monitoring Well Reinstallation On December 16, 1999, a field sampling specialist from ATC arrived on site to develop and sample wells MVV2, MW3, and MW4 The depth to bottom of the new wells was measured at depths ranging from 55 46 to 58 14 ATC was unable to develop the wells due to the presence of grout in the bottom of the wells ' On December 18, 1999, a geologist from ATC and V&W Drilling returned to the site to destroy and reinstall the wells The casing and sandpack were overdnlled and new monitoring wells were installed in accordance with the methods described in Section 2 3 2;_5 Monitorina Well Develoi3ment ' Groundwater monitoring wells MW2, MW3, and MW4 were developed on December 22, 1999 Each well was purged until the extracted water was relatively sediment free Development/purge logs are included in Appendix B Purge water was temporarily stored on site in 55-gallon drums ' After fluid levels had been allowed to stabilize, groundwater levels were obtained from existing well MW 1 and new wells MW2, MW3 and MW4 Fluid Ievels were taken on December 22, 1999, utilizing an electronic water probe capable of measuring with an accuracy of 1/100 of a ' foot Groundwater elevation data are presented in Table 2 The new wells were surveyed on December 22, 1999 and tied into the existing monitoring well ' Survey data is also contained in Table 2 ' 2„6 Groundwater Sampling and Analvsis On December 22, 1999, groundwater samples were collected from wells MW1, MW2, MW3, and MW4 The samples were collected after purging a minimum of three well volumes and stabilization of electric conductivity, pH, and temperature Field development/purge logs are presented in Appendix B Subsequent to purging, groundwater was sampled and transferred to ' appropriate sample containers, using clean, disposable bailers with bottom emptying devices to reduce volatilization Sample containers were then labeled with sample identification, placed on ice, and shipped under chain-of-custody to Sequoia Analytical W w2577veports\sumn doc 3