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Ciealogfut Teeknccs Itm Page 3 2"d Quarter 2003 Groundwater Momtoruig Report Project No 507 2 September 24, 2003 ' Figure 2 shows the location of the well cluster routinely used for calculating the vertical groundwater gradients, MW-9 and MW-109 Table 1 shows Summary of Water Level and ' Gradients Slope and. Bearing, and Table 2 shows the calculated vertical gradients The information used in the calculations is shown below ' Vertical gradient calculation formulas are as follows • Vertical correction for gradient [(gw gradient slope) x (distance) = vertical correction] ' • Vertical head [(head of deep well) - (head of shallow + correction) = vertical head] • Vertical gradient [(vertical head) / (vertical distance) = vertical gradient] For the June 2003 monitoring event a vertical gradient was not calculated for the MW- 9/MW-109 pair due to the variable gradients noted above The historical vertical gradients are negative (a downward direction) and of larger magnitude than the horizontal water table gradients ' 1.2 Groundwater Sampling Procedure On June 24, 2003, Don Light of Del-Tech mobilized to the site to conduct groundwater monitoring of the site's eleven monitoring wells Before sampling was attempted, the wells were sounded for depth to water and then a clear disposable bailer was used to determine if floating product was present No free product was noted for this event The wells were ' purged of at least three well volumes of stagnant water using a dedicated Waterra check-ball assembly and 1/2 inch tubing Purging continued until the temperature, conductivity, and pH of the groundwater stabilized ( ' formation water representative of aquifer conditions was entering the wells These water quality parameters were measured at intervals of each well volume purged ' Once purging was complete, a water sample was collected from the Waterra tube Care was taken to minimize sample agitation Once the sample container was filled and capped, the bottle was inverted, tapped and checked for headspace bubbles The sample container was ' identified and labeled with a unique designation, inserted into a foam holder and placed into an ice chest cooled to 4°C for transport to the laboratory ' All non-disposable sampling equipment was decontaminated using a hot water washer and detergent before and between uses Disposable gloves were used by the technician to collect all samples and were changed with each sample collection A chain of custody document, listing all samples collected, accompanied the samples from ' field to laboratory, thereby providing a means to track the movement of and insure the integrity of the samples