SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

ENVIRO"ENTAL HEALTH bEPARTMENT PQu`" SAN JOAQUIN COUNTY --, Program Coordinators a Donna K. Heran, R.E.H.S. g �. Director 304 East Weber Avenue,Third Floor Carl Borgman, R.E.H.S. Laurie A. Cotulla, R.E.H.S. Stockton,California 95202-2708 Mice Huggins, R.E.H.S., R.D.J. �• • oria, R.E.H.S. La • c4tl FVR� Q Assistant Director Telephone: (209)468-3420 Margaret g Robert McClellon, R,E.H.S. Fax: (209) 464-0138 Jeff Carruesco, R.E.H.S. Website:www.sjgov.org/ehd/ Kasey Foley, R.E.H.S. MS SANDI SARALE DEC 0 4 2006 P O BOX 6066 STOCKTON CA 95206 RE: SARALE FARMS Site Code: 0850 16500 CLIFTON COURT RD STOCKTON CA 95206 San Joaquin County Environmental Health Department (EHD) has received and reviewed Additional Monitoring Well Installation Work Plan Addendum (WPA), dated 17 August 2006, and Monitoring Well Installation Report (MWIR) dated 17 November 2006, both prepared by Advanced GeoEnvironmental, Inc. (AGE) for the above-referenced site. In the WPA, AGE proposes to install an additional groundwater monitoring well screened from 5 to 20 feet below surface grade (bsg) approximately 65 feet north of monitoring well MW-1. Soil samples are proposed to be collected at 5-foot intervals. The purpose of the well is to delineate the northern boundary of the plume of dissolved contaminants released from the underground storage tank (UST) system formerly on your site. During August 2006, additional groundwater monitoring wells (MW-5 through MW-9) were installed on site to assess the sand units underlying the fine grained soil that monitoring wells MW-1 through MW-4 were completed in for dissolved contaminants. Data on Geotracker for the third quarter 2006 groundwater monitoring event shows that the wells on the north side of the buildings were impacted by total petroleum hydrocarbons quantified as gasoline (TPHg), surprisingly, none of the wells sampled during the third quarter 2006 was impacted by 1,2-dichloroethane (1,2-DCA), which has been fairly persistently present in MW-1 through MW-4 at concentrations as high as 71 micrograms per liter. The data indicate to the EHD that the proposed well north of MW-1 is justified to delineate shallow impacted groundwater in fine grained soil, but an additional well in the underlying sand, constructed similar to MW-6 through .MW-9 also appears to be necessary to delineate the northern extent of impacted groundwater as the sand is a potential preferred migration pathway for dissolved contaminants. The EHD believes it would be prudent to monitor MW-5 for a few quarters before deciding on the necessity for additional wells in the second sand interval approximately 50 to 55 feet bsg.