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:p <br /> City of Stockton TL# 394-0192-01 <br /> September 16, 1994 Page 12 <br /> i <br /> �1 <br /> measured using an electronic water sensing meter with a precision <br /> accuracy of + 0.01 feet: The depth to wager in each well at a site <br /> will be measured in a single day. Measurements will be recorded on <br /> the daily field log. <br /> If floating hydrocarbons are suspected, ] a bottom-filling clear <br /> bailer or hydrocarbon detecting paste bailer may be used to record <br /> floating hydrocarbon thickness. The bailer will be lowered to a <br /> point just below the liquid level, retrieved, and observed for <br /> floating hydrocarbon. <br /> ' Groundwater elevations will be calculated by subtracting measured <br /> J <br /> water depths from surveyed casing rim (measuring point) elevations. <br /> The direction of groundwater flow and gradient will be calculated <br /> using the groundwater elevation data. V <br /> A-5 Decontamination: Decontamination procedures will be <br /> implemented to reduce the potential for cross-contamination between <br /> soil borings. <br /> Before, during, and following drilling operations, the augers and <br /> associated drilling and sampling equipment ;� will be thoroughly <br /> cleaned using a high pressure hot water '(steam) washer. The hot <br /> water washer has a pressure of approximately 1, 200 pounds per <br /> square inch and a water temperature of approximately 100 degrees . <br /> Centigrade ( °C) . The sampler and brass sleeves will be washed in <br /> a AlconoxO detergent solution, rinsed with clean tap water, and <br /> air-dried prior to initial use and between each sampling event. <br /> The augers will be steam cleaned prior to the drilling of each soil <br /> boring. <br /> �3I <br /> Prior to construction of monitoring wells, all casings will be <br /> cleaned in the same manner as the drilling equipment. <br /> A-6 Sample Handling and Chain-of-Custody: Records will be <br /> developed for soil and groundwater samples <br /> including: sampling <br /> date, sample type, location, depth, job number, name of sampling <br /> personnel, and method of preservation. Each sample container will <br /> be labelled immediately following collection in the field. Chain- <br /> of-custody protocol, described in United States Environmental <br /> Protection Agency (U.S. EPA) , 1986, Test Methods for Evaluating <br /> Solid Waste, SW-846, 3rd edition, will be followed. Samples will <br /> be placed in an ice chest and maintained at approximately 4°C until <br /> they are delivered to the laboratory. Tlie temperature within the <br /> ice chest will be monitored and recorded during the course of <br /> transport and delivery. Samples will, be accompanied by proper <br /> chain-of-custody documentation. Upon arrival at the laboratory, <br /> the samples will be preserved for analysis infaccordance with U.S. <br /> EPA and state of California requirements�t <br /> i <br /> I <br />