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APPENDIX A: METHODS AND PROCEDURES QAJQC This Appendi\ documents the specific methods, procedures, and materials used to collect and analyze groundwater samples GAUGING AND MEASURING ,%IO 'ITOR WELLS Prior to sampling a-,yell. WAGE personnel obtain three measurements 1 the depth to ground%,,ater (DTN�0, 2 the product thickness using a battery po«ered depth to eater-product interface probe and/or by using a specially designed bailer 3 the total depth-of casing, to calculate the total eater rolume in the �Nell The DTW-product interface probe is 101Nered into the v�ell casing until the instrument signals when the top of free phase floating product (if present) and/or the top of\Nater is reached Tlie 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 bottoin of the well and the tape is read again The tape is calibrated in 0 O1-foot inters 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 level and the difference bem een the top of groundwater and the base of the N�ell is noted to establish -,\ater volume in the 1N ell The probe and tape is washed voth TSP (Tri Sodium Phosphate) and rinsed in distilled water before each measurement WEGE has designed and built bailers that «ill collect a sample of the contents of a \Nell 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, Abo%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 WEGE persorwel purge the %yell by renio-%ing ground"Nater 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 amount of water removed is three borehole volumes, unless otherwise stated