SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

• • San Joaquin County DIRECTOR Fp U,I N Donna Heran,REHS 0. 0 Env ronmental Health Department ASSISTANT DIRECTOR Z. r - 600 East Main Street Laurie Cotulla,REHS Stockton, California 95202-3029 PROGRAM COORDINATORS 111a.1,�. Carl Borgman,REHS c. . . - -._.�P • Mike Huggins, REHS,RDI Website: www.Slgov.org/ehd Margaret Lagorio, REHS Phone: (209)468-3420 Robert McClellon,REHS Fax: (209) 464.0138 Jeff Carruesco, REHS,RDI Kasey Foley,REHS June 16, 2008 Mr. Greg Gaut Comfort Air 1607 Turnpike Road Stockton, California 115206 Subject: Comfort Av r, Incorporated 1607 Turni like Road Stockton, C A 95206-1960 The San Joaquin Cot nty Environmental Health Department (EHD) has reviewed Additional Site Assessment Work Plan dated June 5, 2008, prepared by Advanced GeoEnvironrnental, Inc. (AGE) on your behalf for the above-referenced site. The work plan was submitted in response to an EHD letter datec February 7, 2008, directing additional site investigation be performed to determine if a comin led plume exists between the adjacent property at 1601 Turnpike Road and your property, at d to define the vertical extent of chemicals of concern (COC) in the source area by install g a monitoring well screened between approximately 112 and 117 feet below surface grade (I sg) to monitor the groundwater at this depth. In the work plan A E proposes to advance one cone penetration test (CPT) boring to approximately 130 fei t bsg to electronically characterize subsurface lithological behavior and pore pressures at the 1 cation illustrated on Figure 2 of the work plan. The EHD approves the advancement of the C T boring as presented in the work plan. The EHD has reconsi ered its position that a monitoring well, screened between approximately 112 and 117 feet bsg, is needed in the source area. Instead, the EHD believes the monitoring well installed in the s uree area should be screened within the interval of 80 to 100 feet bsg. This is based on the f lowing: • Analytical res ilts for groundwater samples collected quarterly from MW-13, screened at the same ii iterval proposed by the EHD for the newly-installed monitoring well, have been no detect since May 2005. • Soil samples i ccovered at five-foot intervals while installing monitoring well MW-13, located appro imately thirty-five feet from the proposed well, were described as "gray, sand, medium to coarse grained, some silt, moderately graded (SP)" at 80 to 100 feet bsg. This inl -rval may be a significant lateral contaminant migration pathway.