SITE INFORMATION AND CORRESPONDENCE_FILE 1

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electrical tape. The tubes will then be labeled, inserted into ziplock baggies and placed on ice in an insulated cooler for delivery to the laboratory within 24 hours of collection. Soil from tubes not submitted for chemical analysis will be used to provide lithologic information. All soil samples submitted for chemical analysis will be labeled in the field with an indelible ink pen as they are collected. For each sample, the date and time of sample collection, the sampler's initials, the project name and the designated analyses will be recorded on the label and in the field log book. Soil samples will be identified by a well number -depth combination; for example, a soil sample numbered MW1-5 would indicate a soil sample collected at monitor well MW -1 from 5 feet BGS. 5.4 Soil Sample Analytical Protocol The soil samples submitted for chemical analysis will be trans- ported under chain -of -custody to the WESTON Analytics' Stockton, CA. laboratory. The analytical suite will include benzene, toluene, xylene isomers and ethylbenzene by EPA Method 8020 (aromatic volatile organics) and total petroleum hydrocarbons by Method 8015 modified. WESTON Analytics' Stockton Laboratory is a California certified laboratory. 5.5 Water Sampling At the time of water sampling, the wells will first be checked for the existence of a floating product layer by the use of an oil -water interface probe. If the probe indicates product is present, its thickness will be measured using the probe, and the depth to product and depth to water will be recorded. Regardless of the presence or absence of visually detectable floating product, the total petroleum hydrocarbons sample will then be collected. The sample will be obtained using a clean, transpar- ent teflon bailer lowered into well using new, clean monofill- ament line until the bailer is partially submerged. The bailer will be retrieved and inspected for visual confirmation of the oil -water probe results and its contents will be poured into the appropriate sample container. It may be necessary to lower the bailer more than once in order to obtain enough water to satisfy the analytical method requirements. Once the total petroleum hydrocarbons sample has been collected, the total well depth will be verified. In conjunction with the depth to water measurement, the volume of standing water in the well and the required purge volume will be calculated and record- ed on a standardized well sampling log sheet. It is proposed to purge three standing well casing volumes with a 3 inch submers- ible pump prior to collection of the water samples. The pump will be thoroughly cleaned prior to use with a high pressure potable water spray rinse, and will be cleaned after each well is purged in the same fashion. In the last moments of well purging, - 13 -