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UST Closure Report ABF Freight System,Inc. Manteca,California Page 5 • 4.1 Sampling On March 18, 1998, Ceres Associates, of Concord, California, collected six soil samples and one groundwater sample from the excavation area after the removal of the UST. However, en route to the laboratory the labels of the soil samples were rendered indistinguishable. As such, the groundwater sample (Excavation 11')was the only sample analyzed. On March 20, 1998, North State Environmental collected six additional soil samples and one additional groundwater sample. All the soil samples but one were analyzed. The excavation samples (TI-NW-10'4" and TI-SE-10'4" #2) were collected from the side walls of the excavation at the soil groundwater interface. The sample (D1-4') was collected from the dispenser area by hand auguring 4 feet below the surface of the ground. The stockpile samples (SP1-S and SP1-N) were collected from either side of the stockpile. Soil samples were collected in a 6-inch long, 2-inch diameter brass tube. Upon retrieval of the sample tube, the tube was capped using Teflon tape and a plastic cap, appropriately labeled, and refrigerated pending shipment to the analytical laboratory. The first groundwater sample (Excavation 11') was collected from the bottom of the excavation after the removal of the UST on March 18, 1998. The second groundwater sample (Pit Water) was collected after purging 375 gallons of water from the excavation on March 20, 1998. 4.2 Sample Handling All samples were packaged with fresh ice and packing material. Ice chests used for transporting samples were waterproof and made of plastic. Samples were packed in such a way that they did not touch during shipment. Chain-of-custody forms were signed and sealed in "zip-lock" plastic bags and affixed to the top, inside lid of each ice chest. Laboratory personnel transported the ice chests to the analytical laboratory. Chain-of-custody procedures were used for tracing the possession and handling of individual samples from the time of field collection through laboratory analysis. Documentation of custody is accomplished through a chain-of-custody record that lists each sample and the names of individuals responsible for sample collection, shipment, and receipt. Copies of chain-of-custody forms are given in Appendix 4. Samples submitted to North State Environmental Lab included chain-of-custody records. The chain-of-custody records were properly signed and the date of collection and shipment recorded, along with the sample site identifications and requested analyses for each sample. The laboratory used the chain-of-custody form to document the condition of samples on arrival at the laboratory. Sample labels were affixed to all sample tubes. The sample labels marked in indelible ink with the field sample number and other required information. All labels used on the containers were of a permanent type. • NAPR07ECTS\3272\Plans and Reports\UST Closure Report.doc May 22,1998