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08/21/97 THU 09:06 FAX 909 335 6120 SECOR REDLANDS Z002 INTRODUCTION SECOR International Incorporated (SECOR) has completed two episodes of groundwater sampling and analysis of four monitoring wells installed at the property located on the northeast corner of the intersection of Grant Line Road and proposed Pombo Road, Tracy, California. The following sections present data collected from the referenced sampling episodes along with groundwater chemical data obtained during the installation of the four wells in May 1997. MethodoloQy Well purging and sampling at the propertywas performed at monitoring wells MW-1 through MW-4 on June-24, 1997, and July 9, 1997, respectively. Prior to purging, the depth of groundwater at each well was sounded using a Solinst-brand electronic water level indicator, recorded to the nearest 0.01 foot. Purging of the four wells was accomplished using a 1.5-inch outer-diameter by 3-foot long stainless steel bailer lowered by hand into each well casing with a nylon rope. Prior to initiation of field operations, the bailer was decontaminated by scrubbing with a Liquinox or Alconox detergent solution, double rinsed using distilled water and allowed to dry. Between each well purged and sampled, the bailer was decontaminated following the methods described above. In addition, a new rope was used between each well to minimize potential cross contamination. Prior to sampling each well, approximately three well volumes of water were removed (measured as the annular space of the well casing below the water table) and stored in labeled, 55-gallon steel drums. During purging operations, the groundwater, temperature, conductivity and pH measured using a Cambridge Hydac meter. In addition, the turbidity of the removed water was visually monitored and recorded. The wells were sampled after each of the three parameters of temperature,conductivity and pH had stabilized. Copies of the water sample field data sheets are attached to this report as Appendix A. Groundwater samples were obtained from each of the wells, at the air-water interface, utilizing 1-foot long by 1.5-inch diameter polypropylene bailers. Collected water samples were placed directly into precleaned containers provided by the laboratory. After expelling any trapped air bubbles, the containers were sealed with Teflon-lined septum,screw-on lids. Labels containing sample number,well identification,date and time collected,type of sample, and type of preservative were then affi=d to each container. The sample containers were then placed into a cooler containing ice for delivery under Chain-of-Custody to a laboratory certified to perform hazardous waste testing by the State of California Department of Health Services,Environmental Laboratory Accreditation Program. Copies of the Chain-of-Custody Records are attached to this report as Appendix B. JN 40W7.M-01 TMcr.xrr 1