Laserfiche WebLink
09/25/97 In. "5.4o FAX 510 351 0221 TERRA VAC NOR CAL X001 <br /> tM <br /> VA 1651 Alvarado Street, San Leandro, CA 94577-2636 <br /> 1 Tel (510) 351-8900 U Fax(510) 351-0221 <br /> Mr. Michael hifuma Jr. September 24, 1997 <br /> Senior REHS <br /> LOP/Site Mitigation Unit IV <br /> Public Health Services-Environmental Health Division RPSIVEg <br /> San Joaquin County <br /> 304 East Weber Ave.,Third Floor <br /> Stockton,CA 95202 SEP 2 5 1997 <br /> RE: Former Chevron Station 9-4054 ENVIRONMENTAL HEALTH <br /> 2103 Country Club Boulevard PERMIT/SERVICES <br /> Stockton, CA 95204 <br /> This addendum to the "Additional Soil and Groundwater Investigation Workplan", at the above <br /> referenced location, is prepared in response to your letter dated September 17, 1997. The format <br /> for this addendum is to state the specific concern of Public Health Services-Environmental <br /> Health Division(PHS-EHD)followed by the proposed addenda. <br /> "PHS-EHD recommends that you have your consultant performing this phase of investigation <br /> utilize technology that will also allow groundwater samples to be collected at discreet depths <br /> without cross-contamination from contaminated groundwater at shallower depths. " <br /> Terra Vac is aware of the possibility of cross-contamination during groundwater sample <br /> collection. As a result, intermediate soil samples will not be collected from borings intended for <br /> the collection of discrete groundwater samples. Additionally, Geoprobe sampling equipment <br /> specifically designed for the collection of discrete groundwater samples will be used. <br /> "Although the workplan mentioned "historical low water", it did not specify the maximum depth <br /> at which soil samples would be collected, nor whether or not deep/discreet groundwater samples <br /> would be collected. PHS-EHD is requiring saturated soil and discreet groundwater sampling <br /> from depths below grade known to be "historical drought" depths to groundwater during this <br /> stations operating period. <br /> Terra Vac, subsequent to your letter, has found documentation at the San Joaquin County Flood <br /> Control and Water Conservation Department (SJCFC) indicating that the maximum "historical <br /> drought" occurred in the fall of 1977. The depth to water map included in the Semi Annual <br /> Ground Water Report, Fall 1977 (published by SJCFC) shows the depth of water in proximal to <br /> the site to be between 35 and 40 feet below grade. As a result, Terra Vac is amending the <br /> workplan as follows: <br /> Pinted on teemed paver <br />