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rs 4 The depth to water measurements and the elevations of the well casings (Table 1) were used to evaluate the groundwater flow direction and gradient beneath the site (refer to attached Field Procedures). Groundwater elevation beneath the site rose an average of 0 41 feet since September 28, 1994. The groundwater gradient magnitude and direction was generally consistent during the reporting period. The calculated gradients for October (0 004 ft/ft), November (0 005 ft/ft), and December (0 004 ft/ft) are depicted on Plates 3, 4 and 5, respectively Groundwater flow direction was to the northeast during the reporting period The direction of groundwater flow has ranged from southeast to northeast since groundwater monitoring was initiated in December 1988. On December 30, 1994, groundwater samples were collected from wells MW-1 through MW- 5 for laboratory analyses. The field methods used are presented in Attachment 1 Field purge logs are included in Attachment 2. Groundwater samples were analyzed by Sequoia Analytical for total purgeable petroleum hydrocarbons (equivalent to total petroleum hydrocarbons as gasoline [TPHgl) using Environmental Protection Agency (EPA) Method 5030/8015, total extractable petroleum hydrocarbons (equivalent to total petroleum hydrocarbons as diesel [TPHd] using EPA Method 3520/8015 (modified for gasoline and diesel), and for benzene, toluene, ethylbenzene, and total (BTEX) isomers using EPA Method 8020 Copies of the laboratory reports and chain of custody documentation are included in Attachment 3 0 Results of laboratory analyses indicated dissolved TPHg was detected in the sample from well MW-1 at 1,700 parts per billion (ppb). BTEX constituents were also detected in well MW-1, most notably benzenle at 310 ppb. Hydrocarbon constituents detected in well MW-1 decreased an average of 56% since September 1994. No TPHg or BTEX constituents were detected in any other well. TPHd was detected in wells MW-1, MW-2, MW-3 and MW-5 at 300 ppb, 57 ppb, 120 ppb, and 260 ppb, respectively. The laboratory results of TPHd were reported as non-diesel mix Dissolved TPHd and TPHg concentrations were below laboratory detection limits in monitoring well MW-4. Results of laboratory analyses are summarized in Table 2 SUMMARY AND REC01 EMEE.NDATIONS The groundwater flow direction and gradient were generally consistent with those evaluated during previous events. Dissolved gasoline hydrocarbons were detected in the sample from well MW-1. Dissolved hydrocarbons reported as diesel were detected in wells MW-1, MW-2, MW-3 and MW-5 during flus sampling event Dissolved TPHg and TPHd concentrations were below laboratory detection limits in monitoring well MW-4 Canome recommends forwarding signed copies of this report to Ms. Linda Turkatte of the San Joaquin County Public Health Services, Environmental Health Division, P.O. Box 2009, Stockton, California 95201, and Ms. Elizabeth Thayer of the California Regional Water 38004-IOWQSR44 dae CanonleEnviro=ertal