SITE INFORMATION AND CORRESPONDENCE 1988 - 2001

Home Browse Search

Ms. Diane Hinson San Joaquin County Department of Environmental Health April 14, 1993 Page 2 • After recovery of the water level in the well to 80 % of its pre-cleaning level, the well will be purged off a minimum additional three well volumes of water with an electric submersible pump. The purpose of this purging is to test the use of an electric submersible pump for evacuation of the well on a short term basis and to purge the well for the purpose of sampling. During the purging process, pH, temperature and conductivity will be measured and documented. When these parameters show change within 10% of the previous reading, and the minimum volume of water has been evacuated, a ground water sample will be collected. All purge water will be placed in labeled drums in a secure area of the site. • A ground water sample will then be collected from the purged well. Ground water samples will be collected by lowering a new (precleaned), disposable polyethylene bailer into the well using new, disposable nylon cord. The filled bailer will be retrieved, emptied, then filled again. The ground water from this bailer will be decanted into appropriate laboratory supplied glassware and/or plastic containers (if sample preservatives are required, they will be added to the empty containers at the laboratory prior to the sampling event). The containers will be filled carefully so that no headspace is present to avoid volatilization of the sample. The filled sample containers will then be labeled and placed in a cooler with ice for transport under chain of custody documentation to the designated analytical laboratory. The ESE staff member will document the time and method of sample collection, and the type of sample containers and preservatives (if any) used. These facts will appear on the ESE Ground Water Sampling Data Forms. ESE will collect a duplicate ground- water sample, which will be a blind sample (its well designation will be unknown to the laboratory). The duplicate sample is for Quality Assurance and Quality Control (QA/QC) purposes, and provides a check on. ESE sampling procedures and laboratory sample handling procedures. ESE will include a trip blank in the cooler with the ground water samples for analysis for volatile components. The trip blank is supplied by the laboratory and consists of deionized water. The trip blank is for QA/QC purposes and provides a check on both ESE and laboratory sample handling and storage procedures. Since disposable bailers will be used for sample collection, and will not be reused, no equipment blank (rinsate) samples are collected. • The ground water sample and duplicate will be analyzed at-the laboratory for Total Petroleum Hydrocarbons (TPH) as gasoline, diesel,using methods in 3550/8015 and 5030/8015m, and Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) using Method 8020. • Upon receipt of analyses, ESE will prepare a quarterly report.