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r GBOAAATRIX € Mr. Michael Infurna of SJCEHD was present to observe well location activities. All four monitoring wells were surveyed.on 23 May 1996 by Thompson-Hysell Engineers, Inc. of Modesto, California for Pvertical and horizontal control. �' 3.2 Groundwater Monitoring Field Methods F ! Groundwater monitoring wells MW-3 and MW-4 were sampled on 5 April 1995, well MW-1 was Fsampled on 25 April 1996, and well MW-2 was sampled on 3 May 1996. At the request of Mr. Infurna, groundwater monitoring was performed again in all four wells on 4 June 1996. Groundwater monitor- ing consisted of measuring groundwater levels using an electric sounder, observing the groundwater for the presence of separate-phase petroleum hydrocarbons, and collecting groundwater samples from each well. Prior to collecting groundwater samples, at least four casing volumes of groundwater were purged from each well. Purging was performed using a diaphragm pump and groundwater-samples were collected with a Teflon bailer. During purging, field water quality parameters were monitored and the clarity of the water was observed. Groundwater samples were placed in laboratory-prepared Fcontainers, sealed, labeled, and stored in an ice-cooled chest for subsequent delivery to the laboratory using chain-of-custody procedures. F3.3 Laboratory Analysis Groundwater samples were analyzed using a modified version of EPA Method 8015 for total extract- able hydrocarbons in the C8 to C36 carbon range quantified as crude oil (TEH-C), total extractable hydrocarbons in the C10 to C24 carbon range quantified against a diesel standard (TEH-D), and total `� purgeable hydrocarbons in the C4 to C12 carbon range quantified against a gasoline standard (TPH-G). R : Groundwater samples were also analyzed for BTEX using EPA Method 8020 and PAHs using EPA Method 8310. Laboratory services were provided by Friedman and Bruya, Inc. of Seattle, Washington; American Environmental Network of Pleasant Hill, California; and North Coast Laboratories, LTD., of Arcata, California. Analytical data sheets provided by the laboratories are included in Appendix B. F13.4 Results Analytical results confirm that groundwater at the Monterosso parcel is not impacted by petroleum FA hydrocarbons. Petroleum hydrocarbons were not detected at concentrations above the method detec- tion limits for each analysis in any of the eight samples collected from the groundwater monitoring wells at the site. These results are consistent with those generated by L•F in 1990. Analytical results �# for samples collected by Geomatrix are summarized in Table 4. Groundwater levels are summarized in Table 3. The groundwater gradient on 4 June 1996 was approx- imately 0.001 to the north-northwest. A northerly gradient of low magnitude is consistent with that observed at the Dividend property. Groundwater elevation contours based on water levels measured on 4 June 1996 are shown on Figure 3. 5 1 F '