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APPENDIX A: METHODS AND PROCEDURES QA/QC This Appendix documents the specific methods, procedures, and materials used to collect and analyze groundwater samples GAUGING AND MEASURING MONITOR WELLS Prior to sampling a well, WEGE personnel obtain three measurements 1 the depth to groundwater (DTW), 2 the product thickness using a battery powered depth to water-product interface probe and/or by using a specially designed bailer, 3 the total depth of casing, to calculate the total water volume in the well The DTW-product interface probe is lowered into the well casing until the instrument signals when the top of free phase floating product (if present) and/or the top of water is reached The distance from the top of free phase floating product and/or water to the top of casing is read from the tape that is attached to the probe The probe is then lowered to the bottom of the well and the tape is read again The tape is calibrated in 0 01-foot intervals for accuracy to 0 01 foot The measured distance is subtracted from the established elevation at the top of casing to determine the elevation of groundwater with respect to mean sea level and the difference between the top of groundwater and the base of the well is noted to establish water volume in the well The probe and tape is washed with TSP (Tri Sodium Phosphate) and rinsed in distilled water before each measurement WEGE has designed and built bailers that will collect a sample of the contents of a well to show the exact thickness of any floating product Some of the abbreviations used in water sampling and or measuring or monitoring are BGS, Below Ground Surface, DTW, Depth to Water (from surface reference i e usually TOC), TOC, Top of Casing, MSL, Mean Sea Level, AMSL and BMSL, Above and Below MSL, BS, Below Surface, TOW, Top of Water, TSP, Tri Sodium Phosphate PURGING STANDING WATER FROM MONITOR WELLS If no product is present, WEGE personnel purge the well by removing groundwater until the water duality parameters (temperature, pH, and conductivity) stabilize, or until the well is emptied of water Periodic measurements of groundwater temperature, pH, and conductivity are taken with a Hydac Monitor or other meter and recorded along with the volume of groundwater removed from the well Purging is done by one or more methods singularly or in combination Bailers, pneumatic or electric sample pumps, or vacuum pump tanks or trucks may be used The usual amount of water removed is three borehole volumes, unless otherwise stated