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APPENDIX A: METHODS AND PROCEDURES QA/QC This Appendix documents the specific methods, procedures, and matenals used to collect and analyze groundwater samples GAUGING AND MEASURING INIONITOR '4'4'ELLS Prior to sampling a well WEGE personnel obtain three measurements I the depth to groundwater (DTN'0, 2 the product thickness using a batter), po«ered depth to eater-product interface probe andJor by using a specially designed bailer 3 the total depth"of casing, to calculate the total wvater volume in the «ell The DTW-product interface probe is lowered into the dell casing until the instrument signals when the top of free phase floating product (if present) and/or the top of eater is reached The distance from the top of free phase floating product and/or wafer 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 NAell and the tape is read again The tape is calibrated in Q 41-foot intervals for accuracy to 4 41 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 bem een the top of groundwater and the base of the w ell is noted to establish w ater volume in the ik ell The probe and tape is washed with TSP (Tri Sodium Phosphate) and rinsed in distilled eater before each measurement WEGE has designed and built bailers that will collect a sample of the contents of a «ell to show the exact thickness of any floating product Some of the abbreviations used in eater sampling and or measuring or morutoring are BGS, Below Ground Surface, DTW, Depth to Water (front surface reference i e usually TOC), TOC, Top of Casing, MSL Mean Sea Level, AMSL and BMSL, Aboj e and Below MSL, BS, Below Surface, TOW, Top of Water, TSP, Tri Sodium Phosphate PURGING STANDING WATER FROM IMONITOR WELLS If no pi oduct is present «,EGE personnel purge the is ell by remoN mg groundNN ater until the water quality 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 14onitor 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 usualamount of water removed is three borehole volumes, unless otherwise stated.