|
r
<br /> PHONE 285 2400
<br /> CABLE ADDRESS Tily OIL
<br /> t SEATTLE TE (FAX) 206 283 8036
<br /> TACOMA N
<br /> PORTLAND _
<br /> STOCKTON T6
<br /> RENO ' J• +
<br /> 2
<br /> RICHMOND
<br /> LOS ANGELES y I � "E TIME �n,J li � � �i/—
<br /> o
<br /> K { l
<br /> b 5 TS
<br /> T 2737 WEST COMMODORE WAY SEATLE 98199 1233
<br /> PRODUCTS P O BOX 24447 SEATTLE WA 98124 0447
<br /> TIMETESTED "
<br /> E
<br /> November 2, 1995
<br /> Mr Harlan Knoll
<br /> San Joaquin County Public Health Services
<br /> Environmental Health Division
<br /> P O Box 2009
<br /> Stockton, California 95201
<br /> RE Quarterly Status Report-Thad Quarter 1995 for
<br /> Jackpot Food Mart, 14000 E Highway 88, Lockeford, California (Property No 04-049)
<br /> Dear Mr Knoll,
<br /> At the request of the San Joaquin County Public Health Services Environmental Health Division
<br /> (PHS/EHD), an additional environmental investigation was implemented at the subject site in December
<br /> 1994 to evaluate the extent of hydrocarbon-impacted soils and to determine whether or not groundwater
<br /> had been impacted Based on the results of the investigation, Time Oil has implemented quarterly status
<br /> reporting and quarterly groundwater monitoring
<br /> For your convenience a summary of previous site activities is attached
<br />•
<br /> Groundwater Sampling.Results - October 1995
<br /> On October 4, 1995, samples were collected from each of the groundwater monitoring wells (MW-1
<br /> through MW-4) at the subject site Prior to purging, the depth to water in each well was measured to
<br /> evaluate elevation, flow direction, and gradient
<br /> Analyses identified gasoline and its constituents in groundwater samples collected from each of the
<br /> monitoring wells MW-1, located nearest to the existing pump islands was found to contain 8,200 ppb
<br /> gasoline, 500 ppb benzene, 2,400 ppb toluene, 300 ppb ethylbenzene, and 1,400 ppb xylenes MW-2,
<br /> located on the northeast corner of the property and upgradient of the former tank bed, contained 320 ppb
<br /> gasoline, 9 ppb benzene, 35 ppb toluene, 5 ppb ethylbenzene, and 92 ppb xylenes The sample
<br /> collected from MW-3, located to the southeast of the former tank bed (sidegradient), contained 8,000
<br /> ppb gasoline, 560 ppb benzene, 1,400 ppb toluene, 360 ppb ethylbenzene, and 1,900 ppb xylenes The
<br /> sample collected from MVV-4, locates to the southwest of the former tank bed (sidegradient), contained
<br /> 180 ppb gasoline, 47 ppb benzene, 8 5 ppb toluene, 6 ppb ethylbenzene, and 15 ppb xylenes The
<br /> attached table summarizes all groundwater data collected to date
<br /> Conclusions
<br /> To date, the extent of groundwater impacts have not been defined in any direction Since the previous
<br /> sampling event, gasoline concentrations in MW-1, MW-2, and MW-4 have remained relatively
<br /> unchanged, although BTEX concentrations have increased somewhat in each of the wells Additionally,
<br /> concentrations of gasoline and BTEX have increased in MW-3 by two orders of magnitude The
<br /> observed increases of hydrocarbon constituents in each well may be a result of seasonal variation in
<br /> groundwater levels, however, not enough data has been collected to evaluate the significance of these
<br />. variations Future data will be used to evaluate if significant trends in hydrocarbon concentrations in
<br /> groundwater exist
<br />
|