ARCHIVED REPORTS_REMEDIAL INVESTIGATION REPORT 2000

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r , Quarterly Report - November 1999 FORMER CHASE CHEVROLET(VAN BUREN) FACILITY 424 North Van Buren Street, Stockton, California 1.0. INTRODUCTION At the request of Mr. Jeffery Setness of Jeff B. Setness Professional Law Corp., Advanced GeoEnvironmental, Inc. (AGE) has prepared this quarterly report summarizing field activities performed during the fourth quarter of 1999 at 424 North Van Buren Street, Stockton, California (Figure 1 -Location Map).The scope of work included quarterly ground water monitoring,obtaining laboratory analyses of the samples, start-up of the soil vapor extraction (SVE) and in-situ air sparging(IAS) systems and preparation of this report. Structures and monitoring well locations on the site and adjacent area are illustrated in Figure 2 - Vicinity Map and Figure 3 - Remediation System. Background information was summarized in Corrective Action Plan -December 1996 and in Quarterly Report -May 1999, both prepared by AGE. 2.0. PROCEDURES Field activities were performed in accordance with guidelines established by the Regional Water Quality Control Board - Central Valley Region (RWQCB-CVR) and by the San Joaquin County Public Health Services - Environmental Health Division (PHS-EHD) for the investigation of underground storage tank(UST)sites.Field procedures for the monitoring of the remediation system and performance of ground water monitoring and sampling are described below. 2.1. MONITORING WELL PURGE PROCEDURES On 08 November 1999, a Solinst water level meter was used to measure the depth to ground water in eight monitoring wells and one vapor extraction wells at the site and fourteen monitoring wells at the Madison site relative to the tops of the well casings. An Ullage interface probe was used to measure the depth to ground water in wells MW-3,VW-2, VW-3, and VW-5 and to check for the presence of free product in MW-3,MW-9, VW-2, VW-3, and VW-5. The ground water elevations and hydraulic gradient were determined from these data(Table 1). The well box cover and locking cap were missing from MW-14 upon arrival at the site and were replaced at this time. No obvious infiltration of surface water was observed. After measurement of depths to water,each monitoring well at the site was purged using a two-stage submersible purge pump. The pump was decontaminated prior to purging each well using an Alconox solution and clean tap water. Temperature,pH and conductivity of the purged water were measured at regular intervals during purging using a Hydac water analyzer. Dissolved oxygen was measured in the final purge water using a YSI model 55 dissolved oxygen meter. Approximately ten to fifteen gallons of water were removed from each well except MW-9, from which sixty gallons of water were purged (approximately three well volumes). All purged water was stored in 55-gallon Advanced GeoEnvironmental,Inc.