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j SITE ACTIVITIES SINCE SUBMITTAL OF REIMBURSEMENT REQUEST 5 JACKPOT FOOD MART, 14000E HIGHWAY 88, LOCKEFORD, CALIFORNIA TIME OIL PROPERTY NO. 04-049 Second Quarter 1999 Groundwater Sampling Results—April 1999 On April 26, 1999, samples were collected from.each of the groundwater monitoring wells (MW-1 through MW-10) at the subject site by a representative of SECOR. Prior to purging, the depth to water in each well was measured to evaluate elevation, flow direction, and gradient. Groundwater with a southerly flow direction and a gradient of 0.03;ft./ft. was encountered in the wells at depths of 64.96 feet to 77.00 feet below ground surface. Free product was not encountered in any of the wells. Since the January 1999 sampling event, groundwater elevation increased in MW-3 by 0.02 feet and in VW-9 by 0.06 feet, while it decreased in the remaining wells by 0.01 feet to 1.00 feet. These changes resulted in an -overall-average;decrease_mgroundwater-elevatiort-'of'0.23 feet�acrflssthe=site`�'Changes'in graundwater -� -- `elevation are most likely a result of seasonal variation. Gr'oundwater gradient and flow direction remained consistent with previously collected data. . Analyses performed by Excelchem identified elevated concentrations of hydrocarbons in the samples y collected from MW-1 (2,780 ppb gasoline, 97 ppb.-benzene, 96 ppb toluene, 216 ppb ethylbenzene, 163 ppb xylenes), MW-2 (515 ppb gasoline, 5.2 ppb benzene, 1.0 Ppb toluene, 0.8 Ppb ethylbenzene, and 43.8 ppb l xylenes), MW-3 (306 ppb gasoline, 28.3 ppb benzene, 11.7 ppb toluene, 10.1 ppb ethylbenzene, and 26.5 ppb xylenes), MW-4 (1,810 ppb gasoline, 300 pp6benzene;3.9 ppb toluene, 151 ppb ethylbenzene, and 7,1 ' ppb xyienes), and MW=5 (4,050 ppb gasoline, 395'ppb benzene, 22 ppb toluene, 177 ppb ethylbenzene, and 608 ppb xylenes).: Lower concentrations of hydrocarbons were found in the samples collected from MW-6 (73 ppb gasoline, 5.2 ppb benzene, 0.8 ppb ethylbenzene, and 5.3 ppb xylenes), MW-8 (78 ppb gasoline and 0.9 ppb benzene) and MW-9 (91 ppb gasoline and 2.0 ppb benzene). Hydrocarbons were not detected in the samples collected from MW-7 and MW-10,: Low concentrations of MTBE were detected in the groundwater sample -collected from MWS (25.8 ppb); however, it was not detected in any of the other samples. The highest concentrations.of hydrocarbons appear to remain onsite in the vicinity of the pump islands (MW- 1) and sidegradient of the former tank bed.(MW-5). When compared to the January 1999 sampling event, hydrocarbon concentrations decreased in MW-1I and MW-2 while they decreased in MW-4 and MW-5, Hydrocarbon concentrations remained relatively unchanged in each of the wells. A copy of SECOR's "Quarterly Monitoring Report,"April - June 1999" dated July 28, 1999, was forwarded to the-a ro riate-re ulato a encies on-,-August-2-,,,4999i= Third Quarter 1999 Groundwater Sampling Results and Remediation Activities Third Quarter 1999 Groundwater Sampling Results—July 1999 On July 14, 1999, samples were collected from each of the groundwater monitoring wells (MW-1 through MW-10) at the subject site by a representative of SECOR. Prior to purging, the depth to water in each well was measured to evaluate elevation, flow direction, and gradient. Groundwater with a south-southwesterly flow direction and a gradient of 0.04 ft./ft. was encountered in the wells at depths of 6521 feet to 78.34 feet below ground surface. Free product was not encountered in any of the wells. Since the April 1999 sampling event, groundwater elevation increased in MW-5 by 0.57 feet, while it decreased in the remaining wells by 0.14 feet to 1.34 feet. These changes resulted in an overall average decrease in groundwater elevation of 0.23 feet across the site. Changes in groundwater elevation are most likely a result of seasonal variation. Groundwater gradient and flow direction remained consistent with '` previously collected data.