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APPENDIX A: METHODS ANM PROCEDURES QA/QC This Appendi\ documents the specific methods, procedures, and materials used to collect and analyze groundwater samples GAUGING AND MEASURING INIONITOR WELLS Prior to sampling a well WEGE personnel obtain three measurements 1 the depth to groundv�ater (DTV+'), 2 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 NN ater N olume in the NN ell The DTW-product interface probe is lo\;ered into the «ell casing until the instrument signals NN hen the top of free phase floating product (if present) and/or the top of\;ater is reached The distance from the top of free phase floating product and/or \N ater to the tap of casing is read from the tape that is attached to the probe The probe is then lo"�ered 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 bem een the top of groundNN ater and the base of the �N ell is noted to establish \\ater N plume in the ,N ell The probe and tape is ,vashed NN ith TSP (Tri Sodium Phosphate) and rinsed in distilled water before each measurement WEGE has designed and built bailers that \N ill 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 TOC), TOC, Top of Casing, MSL Mean Sea Level, AMSL and BMSL, Abo1 e and Below MSL, BS, Below Surface, TOW, Top of Water, TSP, Tri Sodium Phosphate PURGING STANDING WATER FROM MONITOR WELLS It no product is present \VEGE peisoninel ourQe the \\ell by iemo,, ing ground\�ater until the water quality parameters (temperature, pH, and conductivity) stabilize, or until the «ell is emptied of water Periodic measurements of groundwater temperature, pH, and conductivity are taken with a Hydac Morutor 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 otherwise stated