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5.0 GROUNDWATER GRADIENT AND FLOW DIRECTION Groundwater depths were measured in each well, prior to purging and sampling on September 25, 1999 Depths were measured relative to the north side of the top of each well casing The monitoring well top-of-casing (TOC) elevations were surveyed relative to an arbitrary benchmark (cluseled square set at southeast corner of residence, assumed elevation of 100 00 feet) on February 19, 1999 by Quartaroh & Associates In each well, groundwater depth was subtracted from the respective well casing elevation to establish a groundwater elevation Cumulative groundwater elevation and gradient data is summarized in Table 3 On the basis of the September 1999 groundwater measurements, groundwater flows to the east- southeast with a surface gradient of 0 03 Figure 3 presents a Generalized Potentiometric Surface Map for the September 1999 groundwater monitoring event 6.0 GROUNDWATER MONITORING WELL SAMPLING BSK performed well sampling activities on September 25, 1999 Prior to purging of the wells for sampling, water from each well was observed for floating product Floating product was not observed in the four monitoring wells The monitoring wells were purged of at least four well- casing volumes Measurements of temperature, conductivity, and pH were measured and recorded after each approximate well volume After tq purging, each monitoring well was allowed to recover, then water samples were collected from each well using a clean disposable bailer The samples were labeled, placed in an ice chest cooled with "blue ace", and submitted to a State-certified analytical laboratory for ' chemical analysis of TPHg and BTEX by EPA Method 8015/8020 (Modified), and fuel oxygenates and 1,2-DCA by EPA Method 8260 Equipment used during purging and sampling activities was cleaned with non-phosphate detergent wash and rinsed prior to use at each well ' location The purged groundwater was stored in appropriately labeled 55-gallon drums at the Site Water Sampling Logs are included in Appendix A 7.0 ANALYTICAL RESULTS A summary of analytical results for the third quarter of 1999 are presented in the following Table A A cumulative summary of quarterly monitoring analytical results as presented an Table 2 Laboratory Data Reports and Cham-of-Custody documentation are included in Appendix B Status Report_07400178 Third Quarts 1999 3