SITE INFORMATION AND CORRESPONDENCE

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APR 19 194 15=41 AT&T FAX 9CeOFX r 2. FMCON proposes to analyze for benzene, toluene, ethylbenzene, and xylenes using EPA method 9020 and total recoverable petroleum hydrocarbons ('I'RPH) using EPA method 418.1 to define the extent of petroleum hydr®carbon impact during Phase L EMCON and CPL do not feel itis necessary to speciate every sample aualyzed from the site. Therefore, total petroleum hydrocarbons as diesel(TPH-D)by EPA method 8015M, and semivolatile organics by EPA method 8270 will be performed on only two samples from one location where significant petroleum hydrocarbou impacts as identified TM or BTEX analysis are present. It should be noted that EPA method 8270 was performed on selected samples during the initial site investigation. A sample collected from boring B-6 at a depth of 15 feet had a TPH-D concentration of 330 rnilligrams"ogram. but no setnivolatile organic constituents were detected. Soil samples collected during Phase II will be analyzed for TRPIT and BTEX by the methods described in Phase L One round of groundwater samples will be collected from all of the existing and new wells (even if floating petroleum hydrocarbons are present) and will be analyzed for BTEX, TRPH,TPH-D,and semivolatile organics using the same methods as in Phase I. 3. EMCON will continuously core any borings drilled for the purpose of installing monitoring wells during the Phase lI program. 4. The filter pack and screen slot size will be selected based on the physical characteristics of the soil encountered in each boring. It is likely that the primary water-bearing unit encountered will be the same gravelly-sand (SW) unit that is being monitored by wells MW-1 and MW-2. A number 3 sand pack and a 0.020-inch slotted screen were used in wells MW-1 and MW-2. 5. EMCON will wait a minimum of 48 hours between development and sampling.EMCON will measure and record EC, temperature, and pH during well purging and will collect a sample after these parameters have stabilized and four casing volumes of groundwater have been purged- 6. EMCON is prepared to begin held work on this project two weeks after obtaining approval from CPL (after CPL obtains final written approval from RWQCB). After Phase I of the investigation is completed. an interim report will be prepared. The report will show the sampling locations and proposed monitoring well locations, as well as the results of soil and water analyses. We would like to thank you once again for granting Chevron Pipe Line Company an extension in the time period allowed to respond to your concerns. As stated in the 10 March 1994 telephone message and fax from Mt. Sint Waldron to you, CPL did not receive your original I I February 1994 letter uulil lain February. Instead, CPL received a letter of that same date addressed Sheila lamb Carroll of Knox, Lemmon, Brady, Anapol*Y & Sheridan (copy }