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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 IMEASURING ItIONITOR WELLS Prior to sampling a�%,ell WEGE personnel obtain three measurements 1 the depth to groundv ater (DT'NN% ? the product thickness using a batter), po«ered depth to N\ater-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 NN ell The DTW-product interface probe is to«ered into the «ell 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 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 inter\als 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.Ievel and the difference between the top of groundwater and the base of the NN ell is noted to establish «ater volume in the v�ell The probe and tape is washed «ith 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 «ell to show the exact thickness of any floating product Some of the abbreviations used in eater sampling and or measuring or monitoring are BGS, Below Ground Surface, DTW, Depth to Water (from surface reference i e usually TQC), TOC, Top of Casing, MSL Mean Sea Level, AMSL and BMSL, Aboxe and Below MSL, BS, Below Surface, TOW, Top of Water, TSP, Tri Sodium Phosphate PURGING STANDING NATER FROM MONITOR WELLS It no product is present NVEGE personnel purge the «ell by renaming ground%%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 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, mount of water removed is three borehole volumes, unless othenvise stated