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<br />San Joaquin County
<br />Environmental Health Department
<br />600 East Main Street
<br />Stockton, California 95202-3029
<br />Website: www.sjgov.org/ehd
<br />Phone: (209) 468-3420
<br />Fax: (209) 464-0138
<br />July 13, 2009
<br />Mr. Donald Helsel
<br />Earthgrains Baking Companies, Incorporated
<br />2651 South Airport Way
<br />Stockton, California 95206
<br />Subject: Earthgrains Baking Companies, Incorporated
<br />2651 South Airport Way
<br />Stockton, California 95206
<br />DIRECTOR
<br />Donna Heran, REHS
<br />ASSISTANT DIRECTOR
<br />Laurie Cotulla, REHS
<br />PROGRAM COORDINATORS
<br />Mike Huggins, RENS, RDI
<br />Margaret Lagorio, REHS
<br />Robert McClellon, REHS
<br />Jeff Carruesco, REHS, RDI
<br />Kasey Foley, REHS
<br />By letter dated June 18, 2009, Philip Environmental Services Corporation Industrial
<br />Outsourcing, LP (PSC) requested a reduction of sampling of wells associated with the
<br />above -referenced site, from quarterly to annually, to comply with the State of California
<br />Water Resources Control Board Resolution No. 2009-0042. In addition, PSC recommended
<br />that only wells: MW -1, MW -7, MW -12, SP -1, SP -2, PZ -1, and PZ -2 be sampled during the
<br />second quarter of each year and analyzed for total petroleum hydrocarbons quantified as
<br />gasoline (TPH-g), benzene, toluene, ethyl benzene, and total xylenes (BTEX), di -isopropyl
<br />ether (DIPE), and 1,2-dichloroethane (1,2 -DCA).
<br />The San Joaquin County Environmental Health Department (EHD) approves the proposed
<br />sampling schedule presented by PSC with the condition that MW -4 and MW -8 be included
<br />in the annual sampling event. Modest concentrations of TPH-g, toluene, ethyl benzene, and
<br />total xylenes continue to be detected in groundwater collected from MW -4, screened
<br />between 23 and 53 feet below ground surface (bgs), and located approximately sixty feet
<br />up -gradient of cone penetration test (CPT) boring CPT -M6 where high concentrations of
<br />contaminants of concern were detected in grab groundwater samples collected at
<br />approximately 53-58 feet bgs. MW -4 is the only well in proximity to CPT -M6 that can
<br />provide needed information since a building prevents further delineation of the petroleum
<br />hydrocarbon plume north of CPT -M6. Although analytical results for groundwater collected
<br />from MW -8 during 2008 and first quarter 2009 indicate that only DIPE is detected at very low
<br />concentrations, MW -8 is the farthest down -gradient well from the source area and continues
<br />to provide information about the plume migration. In summation, annually collect
<br />groundwater during the second quarter of each year from MW -1, MW -4, MW -7, MW -8,
<br />MW -12, SP -1, SP -2, PZ -1, and PZ -2 and analyze the samples from TPH-g, BTEX, DIPE,
<br />and 1.2 -DCA.
<br />The EHD has reviewed Subsurface Investigation Report dated January 16, 2009, and
<br />concurs with the recommendation presented by PSC to conduct a soil vapor evaluation.
<br />Submit an evaluation of the potential for vapor intrusion inside structures at this site.
<br />Residual contaminant concentrations should be compared to Environmental Screening
<br />
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