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CA ARNG Field Quality Assurance Project Plan • Water level sounder; • Plastic buckets; • Bailing frame; • Hand reel; • Large volume stainless steel bailer or PVC bailer; and • Teflon® sample bailer, point source check valve and flow control bottom emptying assembly. Hand Bailing Pre -Sampling Procedures 9.1.5.16 Prior to initiating a well purging, all sampling equipment that may come in contact with well water are decontaminated following the procedure described in Section 9.3 of this field QAPP. Once decontamination is complete, the following steps will be followed prior to purging the well. 1. Measure static water level to determine the minimum volume of water that needs to be purged from the well prior to collection of groundwater samples. Water level measurements will be measured to the nearest 0.01 foot using an electronic water level sounder. The water level is recorded on the groundwater sampling data sheet. 2. Calculate the volume of water to be purged from the well using the minimum purge volume formula. 3. Secure large volume stainlesssteel or PVC bailer to a stainless steel cable. Using a winch or hand reel, slowly lower the bailer to water level. 4. Purge a minimum of three times the volume water in the casing using the stainless steel or PVC bailer. Hand Bailing Well Purging Procedures 9.1.5.17 During purging, water quality measurements, including pH, SC, temperature, and turbidity are performed periodically on samples of the purge water. These measurements are collected six times over an evenly spaced time interval of the required purge. Measurements are noted on the groundwater purge log. 9.1.5.18 Once the minimum three well volumes have been purged and the measured groundwater parameters have been stabilized, the well is considered ready for sampling. Field parameters are considered stabilized when there is less than a 10% change in SC; less than 0.2 unit change in pH; and less than 1 °C change in temperature between consecutive measurements. Sampling will proceed if at least three well volumes have been purged and all other parameters are stabilized. If the water level in a well does not recharge to within 80% of the static water level within one hour, the well is purged dry once more and sampled as soon as 80% recharge has occurred. Hand Bailing Sample Collection Procedures 9.1.5.19 Groundwater samples are collected from all wells by carefully lowering a Teflon® bailer into the water column and allowing the bailer to fill with water. A flow control valve at the bottom of the field QAPP.DOC 9-8 May 2000